Clean Room Tour with NASA’s Next Gen Tracking Data Relay Satellite TDRS-M, Closeout Incident Under Review – Photos

Inside the Astrotech payload processing facility in Titusville, FL,NASA’s massive, insect like Tracking and Data Relay Satellite, or TDRS-M, spacecraft is undergoing preflight processing during media visit on 13 July 2017. TDRS-M will transmit critical science data gathered by the ISS, Hubble and numerous NASA Earth science missions. It is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station for launch on a United Launch Alliance (ULA) Atlas V rocket on 3 August 2017. Credit: Ken Kremer/kenkremer.com

ASTROTECH SPACE OPERATIONS/KENNEDY SPACE CENTER, FL – The last of NASA’s next generation Tracking and Data Relay Satellites (TRDS) designed to relay critical science data and research observations gathered by the International Space Station (ISS), Hubble and dozens of Earth-orbiting Earth science missions is undergoing final prelaunch clean room preparations on the Florida Space Coast while targeting an early August launch – even as the agency reviews the scheduling impact of a weekend “closeout incident” that “damaged” a key component.

Liftoff of NASA’s $408 million eerily insectoid-looking TDRS-M science relay comsat atop a United Launch Alliance (ULA) Atlas V rocket currently scheduled for August 3 may be in doubt following a July 14 work related incident causing damage to the satellite’s Omni S-band antenna while inside the Astrotech Space Operations facility in Titusville, Florida.

“The satellite’s Omni S-band antenna was damaged during final spacecraft closeout activities,” NASA said in an updated status statement provided to Universe Today earlier today, July 16. NASA did not provide any further details when asked.

Everything had been perfectly on track as of Thursday, July 13 as Universe Today participated in an up close media tour and briefing about the massive probe inside the clean room processing facility at Astrotech Space Operations in Titusville, Fl.

On July 13, technicians were busily working to complete final spacecraft processing activities before its encapsulation inside the nose cone of the ULA Atlas V rocket she will ride to space, planned for the next day on July 14. The satellite and pair of payload fairings were stacked in separate high bays at Astrotech on July 13.

Alas the unspecified “damage” to the TDRS-M Omni S-band antenna unfortunately took place on July 14.

Up close clean room visit with NASA’s newest science data relay comsat – Tracking and Data Relay Satellite-M (TDRS-M) inside the Astrotech payload processing facility high bay in Titusville, FL. Two gigantic fold out antennae’s, plus space to ground antenna dish visible inside the ‘cicada like cocoon’ with solar arrays below. Omni S-band antenna at top. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com

TDRS-M was built by Boeing and engineers are now analyzing the damage in a team effort with NASA. However it’s not known exactly during which closeout activity or by whom the damage occurred.

ULA CEO Tory Bruno tweeted that his company is not responsible and referred all questions to NASA. This may indicate that the antennae was not damaged during the encapsulation procedures inside the ULA payload fairing halves.

“NASA and Boeing are reviewing an incident that occurred with the Tracking and Data Relay Satellite (TDRS-M) on July 14 at Astrotech Space Operations in Titusville, Florida. The satellite’s Omni S-band antenna was damaged during final spacecraft closeout activities” stated NASA.

Up close look at the NASA TDRS-M satellite Omni S-band antenna damaged during clean room processing on July 14, 2017. Launch on ULA Atlas V is slated for Aug. 2017. Credit: Julian Leek

TDRS-M looks like a giant insect – or a fish depending on your point of view. It was folded into flight configuration for encapsulation in the clean room and the huge pair of single access antennas resembled a cocoon or a cicada. The 15 foot diameter single access antennas are large parabolic-style antennas and are mechanically steerable.

What does TDRS do? Why is it important? How does it operate?

“The existing Space Network of satellites like TDRS provide constant communications from other NASA satellites like the ISS or Earth observing satellites like Aura, Aqua, Landsat that have high bandwidth data that needs to be transmitted to the ground,” TDRS Deputy Project Manager Robert Buchanan explained to Universe Today during an interview in the Astrotech clean room.

“TRDS tracks those satellites using antennas that articulate. Those user satellites send the data to TDRS, like TDRS-M we see here and nine other TDRS satellites on orbit now tracking those satellites.”

“That data acquired is then transmitted to a ground station complex at White Sands, New Mexico. Then the data is sent to wherever those user satellites want the data to be sent is needed, such as a science data ops center or analysis center.”

Once launched and deployed in space they will “take about 30 to 40 days to fully unfurl,” Buchanan told me in the Astrotech clean room.

Astrotech is located just a few miles down the road from NASA’s Kennedy Space Center and the KSC Visitor Complex housing the finest exhibits of numerous spaceships, hardware items and space artifacts.

Preflight clean room processing inside the Astrotech payload processing facility preparing NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft for launch on ULA Atlas V in Aug. 2017. Credit: Julian Leek

At this time, the TDRS-M website countdown clock is still ticking down towards a ULA Atlas V blastoff on August 3 at 9:02 a.m. EDT (1302 GMT) from Space Launch Complex 41 (SLC-41) on Cape Canaveral Air Force Station, for a late breakfast delight.

The Aug. 3 launch window spans 40 minutes from 9:02 to 9:42 a.m. EDT.

Whether or not the launch date will change depends on the results of the review of the spacecraft’s health by NASA and Boeing. Several other satellites are also competing for launch slots in August.

“The mission team is currently assessing flight acceptance and schedule. TDRS-M is planned to launch Aug. 3, 2017, on an United Launch Alliance (ULA) Atlas V rocket from Cape Canaveral Air Force Station in Florida,” NASA explained.

NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft will be encapsulated inside these two protective payload fairing halves inside the Astrotech payload processing facility high bay in Titusville, FL. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com

TDRS-M, spacecraft, which stands for Tracking and Data Relay Satellite – M is NASA’s new and advanced science data relay communications satellite that will transmit research measurements and analysis gathered by the astronaut crews and instruments flying abroad the International Space Station (ISS), Hubble Space Telescope and over 35 NASA Earth science missions including MMS, GPM, Aura, Aqua, Landsat, Jason 2 and 3 and more.

The TDRS constellation orbits 22,300 miles above Earth and provide near-constant communication links between the ground and the orbiting satellites.

Preflight clean room processing inside the Astrotech payload processing facility preparing NASA’s Tracking and Data Relay Satellite, or TDRS-M, spacecraft for launch on ULA Atlas V in Aug. 2017. Credit: Julian Leek

TRDS-M will have S-, Ku- and Ka-band capabilities. Ka has the capability to transmit as much as six-gigabytes of data per minute. That’s the equivalent of downloading almost 14,000 songs per minute says NASA.

The TDRS program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

TDRS-M is the third satellite in the third series of NASA’s American’s most powerful and most advanced Tracking and Data Relay Satellites. It is designed to last for a 15 year orbital lifetime.

The first TDRS satellite was deployed from the Space Shuttle Challenger in 1983 as TDRS-A.

TDRS-M was built by prime contractor Boeing in El Segundo, California and is the third of a three satellite series – comprising TDRS -K, L, and M. They are based on the Boeing 601 series satellite bus and will be keep the TDRS satellite system operational through the 2020s.

TDSR-K and TDRS-L were launched in 2013 and 2014.

The Tracking and Data Relay Satellite project is managed at NASA’s Goddard Space Flight Center.

TDRS-M was built as a follow on and replacement satellite necessary to maintain and expand NASA’s Space Network, according to a NASA description.

The gigantic satellite is about as long as two school buses and measures 21 meters in length by 13.1 meters wide.

It has a dry mass of 1800 kg (4000 lbs) and a fueled mass of 3,454 kilogram (7,615 lb) at launch.

Tracking and Data Relay Satellite artwork explains how the TDRS constellation enables continuous, global communications coverage for near-Earth spacecraft. Credit: NASA

TDRS-M will blastoff on a ULA Atlas V in the baseline 401 configuration, with no augmentation of solid rocket boosters on the first stage. The payload fairing is 4 meters (13.1 feet) in diameter and the upper stage is powered by a single-engine Centaur.

TDRS-M will be launched to a Geostationary orbit some 22,300 miles (35,800 km) above Earth.

“The final orbital location for TDRS-M has not yet been determined,” Buchanen told me.

The Atlas V booster is being assembled inside the Vertical Integration Facility (VIF) at SLC-41 and will be rolled out to the launch pad the day before liftoff with the TDRS-M science relay comsat comfortably encapsulated inside the nose cone.

NASA/contractor team poses with the Boeing built and to be ULA launched Tracking and Data Relay Satellite-M inside the inside the Astrotech payload processing facility clean room high bay in Titusville, FL, on July 13, 2017. Launch on ULA Atlas V slated for August 2017 from Cape Canaveral Air Force Station, Fl. Credit: Ken Kremer/kenkremer.com

Carefully secured inside its shipping container, the TDRS-M satellite was transported on June 23 by a US Air Force cargo aircraft from Boeing’s El Segundo, California facility to Space Coast Regional Airport in Titusville, Florida, for preflight processing at Astrotech.

Watch for Ken’s onsite TDRS-M and space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Trump Proposes $19.1 Billion 2018 NASA Budget, Cuts Earth Science and Education

NASA acting administrator Robert Lightfoot outlines NASA’s Fiscal Year 2018 budget proposal during a ‘State of NASA’ speech to agency employees held at NASA HQ on May 23, 2017. Credit: NASA TV/Ken Kremer

The Trump Administration has proposed a $19.1 Billion NASA budget request for Fiscal Year 2018, which amounts to a $0.5 Billion reduction compared to the recently enacted FY 2017 NASA Budget. Although it maintains many programs such as human spaceflight, planetary science and the Webb telescope, the budget also specifies significant cuts and terminations to NASA’s Earth Science and manned Asteroid redirect mission as well as the complete elimination of the Education Office.

Overall NASA’s FY 2018 budget is cut approximately 3%, or $560 million, for the upcoming fiscal year starting in October 2017 as part of the Trump Administration’s US Federal Budget proposal rolled out on May 23, and quite similar to the initial outline released in March.

The cuts to NASA are smaller compared to other Federal science agencies also absolutely vital to the health of US scientific research – such as the NIH, the NSF, the EPA, DOE and NIST which suffer unconscionable double digit slashes of 10 to 20% or more.

The highlights of NASA’s FY 2018 Budget were announced by NASA acting administrator Robert Lightfoot during a ‘State of NASA’ speech to agency employees held at NASA HQ, Washington, D.C. and broadcast to the public live on NASA TV.

Lightfoot’s message to NASA and space enthusiasts was upbeat overall.

“What this budget tells us to do is to keep going!” NASA acting administrator Robert Lightfoot said.

“Keep doing what we’ve been doing. It’s very important for us to maintain that course and move forward as an agency with all the great things we’re doing.”

“I want to reiterate how proud I am of all of you for your hard work – which is making a real difference around the world. NASA is leading the world in space exploration, and that is only possible through all of your efforts, every day.”

“We’re pleased by our top line number of $19.1 billion, which reflects the President’s confidence in our direction and the importance of everything we’ve been achieving.”

Lightfoot recalled the recent White House phone call from President Trump to NASA astronaut & ISS Station Commander Peggy Whitson marking her record breaking flight for the longest cumulative time in space by an American astronaut.

Thus Lightfoot’s vision for NASA has three great purposes – Discover, Explore, and Develop.

“NASA has a historic and enduring purpose. It can be summarized in three major strategic thrusts: Discover, Explore, and Develop. These correspond to our missions of scientific discovery, missions of exploration, and missions of new technology development in aeronautics and space systems.”

Lightfoot further recounted the outstanding scientific accomplishments of NASA’s Mars rover and orbiters paving the path for the agencies plans to send humans on a ‘Journey to Mars’ in the 2030s.

“We’ve had a horizon goal for some time now of reaching Mars, and this budget sustains that work and also provides the resources to keep exploring our solar system and look beyond it.”

Lightfoot also pointed to upcoming near term science missions- highlighting a pair of Mars landers – InSIGHT launching next year as well as the Mars 2020 rover. Also NASA’s next great astronomical observatory – the James Webb Space Telescope (JWST).

“In science, this budget supports approximately 100 missions: 40 missions currently preparing for launch & 60 operating missions.”

“The James Webb Space Telescope is built!” Lightfoot gleefully announced.

“It’s done testing at Goddard and now has moved to Johnson for tests to simulate the vacuum of space.”

JWST is the scientific successor to the Hubble Space Telescope and slated for launch in Oct. 2018. The budget maintains steady support for Webb.

The 18-segment gold coated primary mirror of NASA’s James Webb Space Telescope is raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on Nov. 2, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

The Planetary Sciences division receives excellent support with a $1.9 Billion budget request. It includes solid support for the two flagship missions – Mars 2020 and Europa Clipper as well as the two new Discovery class missions selected -Lucy and Psyche.

“The budget keeps us on track for the next selection for the New Frontiers program, and includes formulation of a mission to Jupiter’s moon Europa.”

SLS and Orion are making great progress. They are far beyond concepts, and as I mentioned, components are being tested in multiple ways right now as we move toward the first flight of that integrated system.”

NASA is currently targeting the first integrated launch of SLS and Orion on the uncrewed Exploration Mission-1 (EM-1) for sometime in 2019.

Top NASA managers recently decided against adding a crew of two astronauts to the flight after conducting detailed agency wide studies at the request of the Trump Administration.

NASA would have needed an additional $600 to $900 to upgrade EM-1 with humans.

Unfortunately Trump’s FY 2018 NASA budget calls for a slight reduction in development funding for both SLS and Orion – thus making a crewed EM-1 flight fiscally unviable.

The newly assembled first liquid hydrogen tank, also called the qualification test article, for NASA’s new Space Launch System (SLS) heavy lift rocket lies horizontally beside the Vertical Assembly Center robotic weld machine (blue) on July 22, 2016. It was lifted out of the welder (top) after final welding was just completed at NASA’s Michoud Assembly Facility in New Orleans. Credit: Ken Kremer/kenkremer.com

The budget request does maintain full funding for both of NASA’s commercial crew vehicles planned to restore launching astronauts to low Earth orbit (LEO) and the ISS from US soil on US rockets – namely the crewed Dragon and CST-100 Starliner – currently under development by SpaceX and Boeing – thus ending our sole reliance on Russian Soyuz for manned launches.

“Working with commercial partners, NASA will fly astronauts from American soil on the first new crew transportation systems in a generation in the next couple of years.”

“We need commercial partners to succeed in low-Earth orbit, and we also need the SLS and Orion to take us deeper into space than ever before.”

Orion crew module pressure vessel for NASA’s Exploration Mission-1 (EM-1) is unveiled for the first time on Feb. 3, 2016 after arrival at the agency’s Kennedy Space Center (KSC) in Florida. It is secured for processing in a test stand called the birdcage in the high bay inside the Neil Armstrong Operations and Checkout (O&C) Building at KSC. Launch to the Moon is slated in 2018 atop the SLS rocket. Credit: Ken Kremer/kenkremer.com

However the Trump Administration has terminated NASA’s somewhat controversial plans for the Asteroid Redirect Mission (ARM) – initiated under the Obama Administration – to robotically retrieve a near Earth asteroid and redirect it to lunar orbit for a visit by a crewed Orion to gather unique asteroidal samples.

“While we are ending formulation of a mission to an asteroid, known as the Asteroid Redirect Mission, many of the central technologies in development for that mission will continue, as they constitute vital capabilities needed for future human deep space missions.”

Key among those vital capabilities to be retained and funded going forward is Solar Electric Propulsion (SEP).

“Solar electric propulsion (SEP) for our deep space missions is moving ahead as a key lynchpin.”

The Trump Administration’s well known dislike for Earth science and disdain of climate change has manifested itself in the form of the termination of 5 current and upcoming science missions.

NASA’s FY 2018 Earth Science budget suffers a $171 million cut to $1.8 Billion.

“While we are not proposing to move forward with Orbiting Carbon Observatory-3 (OCO-3), Plankton, Aerosol, Cloud, ocean Ecosystem (PACE), Climate Absolute Radiance and Refractivity Observatory Pathfinder (CLARREO PF), and the Radiation Budget Instrument (RBI), this budget still includes significant Earth Science efforts, including 18 Earth observing missions in space as well as airborne missions.”

The DSCOVR Earth-viewing instruments will also be shut down.

NASA’s Office of Education will also be terminated completely under the proposed FY 2018 budget and the $115 million of funding excised.

“While this budget no longer supports the formal Office of Education, NASA will continue to inspire the next generation through its missions and the many ways that our work excites and encourages discovery by learners and educators. Let me tell you, we are as committed to inspiring the next generation as ever.”

Congress will now have its say and a number of Senators, including Republicans says Trumps budget is DOA.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

Early Earth Was Almost Entirely Underwater, With Just A Few Islands

Earth's Hadean Eon is a bit of a mystery to us, because geologic evidence from that time is scarce. Researchers at the Australian National University have used tiny zircon grains to get a better picture of early Earth. Credit: NASA

It might seem unlikely, but tiny grains of minerals can help tell the story of early Earth. And researchers studying those grains say that 4.4 billion years ago, Earth was a barren, mountainless place, and almost everything was under water. Only a handful of islands poked above the surface.

Scientists at the Australian National University are behind this study, led by researcher Dr. Antony Burnham. The mineral grains in the study are the oldest rocks ever found. They’re 4.4 billion year old zircon mineral grains from the Jack Hills of Western Australia, where they were preserved in sandstone formations.

4.4 billion years ago, the Earth was in what is called the ‘Hadean Eon’. This time period is poorly understood, because there is no rock record dating from that time. This is where the zircon mineral grains come in.

“The history of the Earth is like a book with its first chapter ripped out with no surviving rocks from the very early period, but we’ve used these trace elements of zircon to build a profile of the world at that time.” – Lead Researcher Dr. Antony Burnham, Australian National University

In a sense, these zircon grains are the missing pages.

Zircon’s chemical name is zirconium silicate, and it’s found almost everywhere in the Earth’s crust. This study focuses on what’s called detrital zircon, which is formed in igneous rocks, but then survives over time until deposited in sedimentary rocks. Zircon grains are typically very small, about 0.1 to 0.3 mm in size.

Zircon crystals from the Jack Hills in western Australia are the oldest rock fragments ever found. Image: Stuart Hay, ANU
Zircon crystals from the Jack Hills in western Australia are the oldest rock fragments ever found. Image: Stuart Hay, ANU

Zircon commonly contains traces of thorium and uranium, which means they can be easily dated by modern dating methods. Zircon can survive a lot of geologic processes like metamorphism, which explains their usefulness in studying the early Earth. They’re not easily destroyed, and they have a story to tell us.

The zircon grains were crystallized in magma about 500 million years after the Earth formed. As a result, they offer rare insights into conditions on Earth at the time. The zircon grains in question are referred to as detritus, because they formed in magma but were deposited in the geologically-important sandstone at Jack Hills, Australia. The detritus grains were compared to a second type of zircon grain which were formed directly in the sedimentary formations.

By distinguishing between the two types, researchers gain a new geochemical tool to understand early Earth.

The Jack Hills in Western Australia contain the oldest rocks known to exist on Earth. A team studying them concludes that early Earth was mostly a water world. By NASA Earth Observatory - http://earthobservatory.nasa.gov/Study/Zircon/zircon.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=738512
The Jack Hills in Western Australia contain the oldest rocks known to exist on Earth. A team studying them concludes that early Earth was mostly a water world. By NASA Earth Observatory – http://earthobservatory.nasa.gov/Study/Zircon/zircon.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=738512

“We used the granites of southeast Australia to decipher the link between zircon composition and magma type, and built a picture of what those missing rocks were,” he said.

“Our research indicates there were no mountains and continental collisions during Earth’s first 700 million years or more of existence – it was a much more quiet and dull place,” says Dr. Burnham from the ANU Research School of Earth Sciences.

The detrital zircons formed elsewhere, but were deposited in the Jack Hills formation. By Robert Simmon, NASA - http://earthobservatory.nasa.gov/Study/Zircon/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4258701
The detrital zircons formed elsewhere, but were deposited in the Jack Hills formation. By Robert Simmon, NASA – http://earthobservatory.nasa.gov/Study/Zircon/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4258701

“Our findings also showed that there are strong similarities with zircon from the types of rocks that predominated for the following 1.5 billion years, suggesting that it took the Earth a long time to evolve into the planet that we know today.” The team’s results are published in the journal Nature Geoscience, and is titled “Formation of Hadean granites by melting of igneous crust.”

Dr. Antony Burnham from the Australian National University's Research School of Earth Sciences, led this study. Image: Stuart Hay, ANU.
Dr. Antony Burnham from the Australian National University’s Research School of Earth Sciences, led this study. Image: Stuart Hay, ANU.

This is not the first time that ancient, detrital zircons have been at the center of scientific studies of early Earth. In a previous study, they were used to conclude that Earth had a significant hydrosphere 4.3 billion years ago.

SpaceX Launching NASA Jason-3 Ocean Surveillance Satellite Jan. 17; with Barge Rocket Landing – Watch Live

The joint NASA-European ocean surveillance satellite named Jason-3 is poised for blastoff from SpaceX’s California launch pad on Sunday, Jan. 17 – followed immediately by another Falcon 9 rocket recovery landing on a barge at sea.

The weather forecast is outstanding! And you can watch all the excitement live!

The primary goal is to deliver Jason-3 to low Earth orbit, where it will gather global measurements of ocean topography, or wave heights, using radar altimitry. These data provide scientists with essential information about global and regional changes in the Earth’s seas such as tracking sea level rise that threatens the resilience of coastal communities and the health of our environment. Continue reading “SpaceX Launching NASA Jason-3 Ocean Surveillance Satellite Jan. 17; with Barge Rocket Landing – Watch Live”

Who Was Democritus?

As the philosopher Nietzsche famously said “He who would learn to fly one day must first learn to stand and walk and run and climb and dance; one cannot fly into flying.” This is certainly true when it comes to humanity’s understanding of the universe, something which has evolved over many thousands of years and been the subject of ongoing discovery.

And along the way, many names stand out as examples of people who achieved breakthroughs and helped lay the foundations of our modern understanding. One such person is Democritus, an ancient Greek philosopher who is viewed by many as being the “father of modern science”. This is due to his theory of universe that is made up of tiny “atoms”, which bears a striking resemblance to modern atomic theory.

Though he is typically viewed as one of Greece’s many pre-Socratic natural philosopher, many historians have argued that he is more rightly classified as a scientist, at least when compared to his contemporaries. There has also been significant controversy – particularly in Germany during the 19th century – over whether or not Democritus deserves credit for atomic theory.

This argument is based on the relationship Democritus had with contemporary philosopher Leucippus, who is renowned for sharing his theory about atoms with him. However, their theories came down to a different basis, a distinction that allows Democritus to be given credit for a theory that would go on to become a staple of the modern scientific tradition.

Hendrik ter Brugghen - Heraclitus, 1628. Credit: rijksmuseum.nl
Democritus, by Hendrik ter Brugghen – Heraclitus, 1628. Credit: rijksmuseum.nl

Birth and Early Life:

The precise date and location of Democritus birth is the subject the debate. While most sources claim he was born in Abdera, located in the northern Greek province of Thrace, around 460 BCE. However, other sources claim he was born in Miletus, a coastal city of ancient Anatolia and modern-day Turkey, and that he was born in 490 BCE.

It has been said that Democritus’ father was from a noble family and so wealthy that he received the Persian king Xerxes on the latter’s march through Abdera during the Second Persian War (480–479 BC). It is further argued that as a reward for his service, the Persian monarch gave his father and other Abderites gifts, and left several Magi among them. Democritus was apparently instructed by these Magi in astronomy and theology.

After his father had died, Democritus used his inheritance to finance a series of travels to distant countries. Desiring to feed his thirst for knowledge, Democritus traveled extensively across the known world, traveling to Asia, Egypt and (according to some sources) venturing as far as India and Ethiopia. His writings include descriptions of the the cities of Babylon and Meroe (in modern-day Sudan).

Upon returning to his native land, he occupied himself with the study of natural philosophy. He also traveled throughout Greece to acquire a better knowledge of its cultures and learned from many of Greece’s famous philosophers. His wealth allowed him to purchase their writings, and he wrote of them in his own works. In time, he would become one of the most famous of the pre-Socratic philosophers.

The ruins of the ancient Greeof Abdera, with the west gate shown. Credit:
The ruins of the ancient Greek city of Abdera, with the west gate shown. Credit: Wikipedia Commons/Marysas

Leucippus of Miletus had the greatest influence on him, becoming his mentor and sharing his theory of atomism with him. Democritus is also said to have known Anaxagoras, Hippocrates and even Socrates himself (though this remains unproven). During his time in Egypt, he learned from Egyptian mathematicians, and is said to have become acquainted with the Chaldean magi in Assyria.

In the tradition of the atomists, Democritus was a thoroughgoing materialists who viewed the world in terms of natural laws and causes. This differentiated him from other Greek philosophers like Plato and Aristotle, for whom philosophy was more teleological in nature – i.e. more concerned with the purpose of events rather than the causes, as well things like essence, the soul, and final causes.

According to the many descriptions and anecdotes about Democritus, he was known for his modesty, simplicity, and commitment to his studies. One story claims he blinded himself on purpose in order to be less distracted by worldly affairs (which is believed to be apocryphal). He was also known for his sense of humor and is commonly referred to as the “Laughing Philosopher” – for his capacity to laugh at human folly. To his fellow citizens, he was also known as “The Mocker”.

Scientific Contributions:

Democritus is renowned for being a pioneer of mathematics and geometry. He was among the first Greek philosophers to observe that a cone or pyramid has one-third the volume of a cylinder or prism with the same base and height. While none of his works on the subject survived the Middle Ages, his mathematical proofs are derived from other works with contain extensive citations to titles like On Numbers, On Geometrics, On Tangencies, On Mapping, and On Irrationals.

Right circular and oblique circular cones. Credit: Dominique Toussaint
Right circular and oblique circular cones. Credit: Dominique Toussaint

Democritus is also known for having spent much of his life experimenting with and examining plants and minerals. Similar to his work in mathematics and geometry, citations from existing works are used to infer the existence of works on the subject. These include On the Nature of Man, the two-volume collection On Flesh, On Mind, On the Senses, On Flavors, On Colors, Causes concerned with Seeds and Plants and Fruits, and to the three-volume collection Causes concerned with Animals.

From his examination of nature, Democritus developed what could be considered some of the first anthropological theories. According to him, human beings lived short lives in archaic times, forced to forage like animals until fear of wild animals then drove them into communities. He theorized that such humans had no language, and only developed it through the need to articulate thoughts and ideas.

Through a process of trial and error, human beings developed not only verbal language, but also symbols with which to communicate (i.e. written language), clothing, fire, the domestication of animals, and agriculture. Each step in this process led to more discoveries, more complex behaviors, and the many things that came to characterize civilized society.

In terms of astronomy and cosmology, Democritus was a proponent of the spherical Earth hypothesis. He believed that in the original chaos from which the universe sprang, the universe was composed of nothing but tiny atoms that came together to form larger units (a theory which bears a striking resemblance to The Big Bang Theory and Nebular Theory). He also believed in the existence of many worlds, which were either in state of growth or decay.

In a similar vein, Democritus advanced a theory of void which challenged the paradoxes raised by his fellow Greek philosophers, Parmenides and Zeno – the founders of metaphysical logic. According to these men, movement cannot exist because such a thing requires there to be a void – which is nothing, and therefore cannot exist. And a void cannot be termed as such if it is in fact a definable, existing thing.

To this, Democritus and other atomists argued that since movement is an observable phenomena, there must be a void. This idea previewed Newton’s theory of absolute space, in which space exists independently of any observer or anything external to it. Einstein’s theory of relativity also provided a resolution to the paradoxes raised by Parmenides and Zeno, where he asserted that space itself is relative and cannot be separated from time.

Democritus’ thoughts on the nature of truth also previewed the development of the modern scientific method. According to Democritus, truth is difficult, because it can only be perceived through senses-impressions which are subjective. Because of this, Aristotle claimed in his Metaphysics that Democritus was of the opinion that “either there is no truth or to us at least it is not evident.”

However, as Diogenes Laertius quoted in his 3rd century CE tract, Lives and Opinions of Eminent Philosophers: “By convention hot, by convention cold, but in reality atoms and void, and also in reality we know nothing, since the truth is at bottom.”

Diogenes Laërtius: Lives and Opinions of Eminent Philosophers. A biography of the Greek philosophers. Title page from year 1594. Credit: Public Domain
Diogenes Laertius, Lives and Opinions of Eminent Philosophers, makes mention of Democritus and his theories. Credit: Public Domain

Ultimately, Democritus’ opinion on truth came down to a distinction between two kinds of knowledge – “legitimate” (or “genuine”) and bastard (or “secret”). The latter is concerned with perception through the senses, which is subjective by nature. This is due to the fact that our sense-perception are influence by the shape and nature of atoms as they flow out from the object in question and make an impression on our senses.

“Legitimate” knowledge, by contrast, is achieved through the intellect, where sense-data is elaborated through reasoning. In this way, one can get from “bastard” impressions to the point where things like connections, patterns and causality can be determined. This is consistent with the inductive reasoning method later elaborated by Renee Descartes, and is a prime example of why Democritus is considered to be an early scientific thinker.

Atomic Theory:

However, Democritus greatest contribution to modern science was arguably the atomic theory he elucidated. According to Democritus’ atomic theory, the universe and all matter obey the following principles:

  • Everything is composed of “atoms”, which are physically, but not geometrically, indivisible
  • Between atoms, there lies empty space
  • Atoms are indestructible
  • Atoms have always been, and always will be, in motion
  • There are an infinite number of atoms, and kinds of atoms, which differ in shape, and size.

He was not alone in proposing atomic theory, as both his mentor Leucippus and Epicurus are believed to have proposed the earliest views on the shapes and connectivity of atoms. Like Democritus, they believed that the solidity of a material corresponded to the shape of the atoms involved – i.e. iron atoms are hard, water atoms are smooth and slippery, fire atoms are light and sharp, and air atoms are light and whirling.

Democritus' model of an atom was one of an intert solid that ineracted mechanically with other atoms. Credit: .science.edu.sg
Democritus’ model of an atom was one of an inert solid that interacted mechanically with other atoms. Credit: .science.edu.sg

However, Democritus is credited with illustrating and popularizing the concept, and for his descriptions of atoms which survived classical antiquity to influence later philosophers. Using analogies from our sense experiences, Democritus gave a picture or an image of an atom that distinguished them from each other by their shape, size, and the arrangement of their parts.

In essence, this model was one of an inert solid that excluded other bodies from its volume, and which interacted with other atoms mechanically. As such, his model included physical links (i.e. hooks and eyes, balls and sockets) that explained how connections occurred between them. While this bears little resemblance to modern atomic theory (where atoms are not inert and interact electromagnetically), it is more closely aligned with that of modern science than any other theory of antiquity.

While there is no clear explanation as to how scholars of classical antiquity came to theorize the existence of atoms, the concept proved to be influential, being picked up by Roman philosopher Lucretius in the 1st century CE and again during the Scientific Revolution. In addition to being indispensable to modern molecular and atomic theory, it also provided an explanation as to why the concept of a void was necessary in nature.

If all matter was composed of tiny, indivisible atoms, then there must also be a great deal of open space between them. This reasoning has also gone on to inform out notions of cosmology and astronomy, where Einstein’s theory of special relativity was able to do away with the concept of a “luminiferous aether” in explaining the behavior of light.

Early atomic theory stated that different materials had differently shaped atoms. Credit: github.com
Early atomic theory stated that different materials had differently shaped atoms. Credit: github.com

Diogenes Laertius summarized Democritus atomic theory as follows in Lives and Opinions of Eminent Philosophers:

“That atoms and the vacuum were the beginning of the universe; and that everything else existed only in opinion. That the worlds were infinite, created, and perishable. But that nothing was created out of nothing, and that nothing was destroyed so as to become nothing. That the atoms were infinite both in magnitude and number, and were borne about through the universe in endless revolutions. And that thus they produced all the combinations that exist; fire, water, air, and earth; for that all these things are only combinations of certain atoms; which combinations are incapable of being affected by external circumstances, and are unchangeable by reason of their solidity.”

Death and Legacy:

Democritus died at the age of ninety, which would place his death at around 370 BCE; though some writers disagree, with some claiming he lived to 104 or even 109. According to Marcus Aurelius’ book Meditations, Democritus was eaten by lice or vermin, although in the same passage he writes that “other lice killed Socrates”, implying that this was meant metaphorically. Since Socrates died at the hands of the Athenian government who condemned him, it is possible that Aurelius attributed Democritus death to human folly or politics.

While Democritus was highly esteemed amongst his contemporaries, there were also those who resented him. This included Plato who, according to some accounts, disliked him so much that he wished that all his books would be burned. However, Plato’s pupil Aristotle was familiar with the works of Democritus and mentioned him in both Metaphysics and Physics, where he described him as a “physicist” who did not concern himself with the ideals of form or essence.

Democritus meditating on the seat of the soul by Léon-Alexandre Delhomme (1868). Credit: Pubic Domain
Democritus meditating on the seat of the soul, by Léon-Alexandre Delhomme (1868). Credit: Pubic Domain

Ultimately, Democritus is credited as being one of the founders of the modern science because his methods and theories closely resemble those of modern astronomers and physicists. And while his version of the atomic model differs greatly from our modern conceptions, his work was of undoubted value, and was a step in an ongoing process that included such scientists as John Dalton, Neils Bohr and even Albert Einstein.

As always, science is an process of continuing discovery, where new breakthroughs are built upon the foundations of the old and every generations attempts to see a little farther by standing on the shoulders of those who came before.

We have many interesting articles about atomic theory here at Universe Today. Here’s one about John Dalton’s atomic model, Neils Bohr’s atomic model, the “Plum Pudding” atomic model.

For more information, check out The History of the Atom – Democritus.

Astronomy Cast has a wonderful episode on the subject, titled Episode 392: The Standard Model – Intro

What are the Earth’s Layers?

The Earth's layers, showing the Inner and Outer Core, the Mantle, and Crust. Credit: discovermagazine.com

There is more to the Earth than what we can see on the surface. In fact, if you were able to hold the Earth in your hand and slice it in half, you’d see that it has multiple layers. But of course, the interior of our world continues to hold some mysteries for us. Even as we intrepidly explore other worlds and deploy satellites into orbit, the inner recesses of our planet remains off limit from us.

However, advances in seismology have allowed us to learn a great deal about the Earth and the many layers that make it up. Each layer has its own properties, composition, and characteristics that affects many of the key processes of our planet. They are, in order from the exterior to the interior – the crust, the mantle, the outer core, and the inner core. Let’s take a look at them and see what they have going on.

Modern Theory:

Like all terrestrial planets, the Earth’s interior is differentiated. This means that its internal structure consists of layers, arranged like the skin of an onion. Peel back one, and you find another, distinguished from the last by its chemical and geological properties, as well as vast differences in temperature and pressure.

Our modern, scientific understanding of the Earth’s interior structure is based on inferences made with the help of seismic monitoring. In essence, this involves measuring sound waves generated by earthquakes, and examining how passing through the different layers of the Earth causes them to slow down. The changes in seismic velocity cause refraction which is calculated (in accordance with Snell’s Law) to determine differences in density.

Model of a flat Earth
Model of a flat Earth, with the continents modeled in a disk-shape and Antarctica as an ice wall. Credit: Wikipedia Commons

These are used, along with measurements of the gravitational and magnetic fields of the Earth and experiments with crystalline solids that simulate pressures and temperatures in the Earth’s deep interior, to determine what Earth’s layers looks like. In addition, it is understood that the differences in temperature and pressure are due to leftover heat from the planet’s initial formation, the decay of radioactive elements, and the freezing of the inner core due to intense pressure.

History of Study:

Since ancient times, human beings have sought to understand the formation and composition of the Earth. The earliest known cases were unscientific in nature – taking the form of creation myths or religious fables involving the gods. However, between classical antiquity and the medieval period, several theories emerged about the origin of the Earth and its proper makeup.

Most of the ancient theories about Earth tended towards the “Flat-Earth” view of our planet’s physical form. This was the view in Mesopotamian culture, where the world was portrayed as a flat disk afloat in an ocean. To the Mayans, the world was flat, and at it corners, four jaguars (known as bacabs) held up the sky. The ancient Persians speculated that the Earth was a seven-layered ziggurat (or cosmic mountain), while the Chinese viewed it as a four-side cube.

By the 6th century BCE, Greek philosophers began to speculate that the Earth was in fact round, and by the 3rd century BCE, the idea of a spherical Earth began to become articulated as a scientific matter. During the same period, the development of a geological view of the Earth also began to emerge, with philosophers understanding that it consisted of minerals, metals, and that it was subject to a very slow process of change.

Edmond Halley's model of a Hallow Earth, one that was made up of concentric spheres.
Illustration of Edmond Halley’s model of a Hallow Earth, one that was made up of concentric spheres. Credit: Wikipedia Commons/Rick Manning

However, it was not until the 16th and 17th centuries that a scientific understanding of planet Earth and its structure truly began to advance. In 1692, Edmond Halley (discoverer of Halley’s Comet) proposed what is now known as the “Hollow-Earth” theory. In a paper submitted to Philosophical Transactions of Royal Society of London, he put forth the idea of Earth consisting of a hollow shell about 800 km thick (~500 miles).

Between this and an inner sphere, he reasoned there was an air gap of the same distance. To avoid collision, he claimed that the inner sphere was held in place by the force of gravity. The model included two inner concentric shells around an innermost core, corresponding to the diameters of the planets Mercury, Venus, and Mars respectively.

Halley’s construct was a method of accounting for the values of the relative density of Earth and the Moon that had been given by Sir Isaac Newton, in his Philosophiæ Naturalis Principia Mathematica (1687) – which were later shown to be inaccurate. However, his work was instrumental to the development of geography and theories about the interior of the Earth during the 17th and 18th centuries.

Another important factor was the debate during the 17th and 18th centuries about the authenticity of the Bible and the Deluge myth. This propelled scientists and theologians to debate the true age of the Earth, and compelled the search for evidence that the Great Flood had in fact happened. Combined with fossil evidence, which was found within the layers of the Earth, a systematic basis for identifying and dating the Earth’s strata began to emerge.

Credit: minerals.usgs.gov
The growing importance of mining in the 17th and 18th centuries, particularly for precious metals, led to further developments in geology and Earth sciences. Credit: minerals.usgs.gov

The development of modern mining techniques and growing attention to the importance of minerals and their natural distribution also helped to spur the development of modern geology. In 1774, German geologist Abraham Gottlob Werner published Von den äusserlichen Kennzeichen der Fossilien (On the External Characters of Minerals) which presented a detailed system for identifying specific minerals based on external characteristics.

In 1741, the National Museum of Natural History in France created the first teaching position designated specifically for geology. This was an important step in further promoting knowledge of geology as a science and in recognizing the value of widely disseminating such knowledge. And by 1751, with the publication of the Encyclopédie by Denis Diderot, the term “geology” became an accepted term.

By the 1770s, chemistry was starting to play a pivotal role in the theoretical foundation of geology, and theories began to emerge about how the Earth’s layers were formed. One popular idea had it that liquid inundation, like the Biblical Deluge, was responsible for creating all the geological strata. Those who accepted this theory became known popularly as the Diluvianists or Neptunists.

Another thesis slowly gained currency from the 1780s forward, which stated that instead of water, strata had been formed through heat (or fire). Those who followed this theory during the early 19th century referred to this view as Plutonism, which held that the Earth formed gradually through the solidification of molten masses at a slow rate. These theories together led to the conclusion that the Earth was immeasurably older than suggested by the Bible.

HMS Beagle in the Galapagos (painted by John Chancellor) - Credit: hmsbeagleproject.otg
HMS Beagle in the Galapagos Islands, painted by John Chancellor. Credit: hmsbeagleproject.otg

In the early 19th century, the mining industry and Industrial Revolution stimulated the rapid development of the concept of the stratigraphic column – that rock formations were arranged according to their order of formation in time. Concurrently, geologists and natural scientists began to understand that the age of fossils could be determined geologically (i.e. that the deeper the layer they were found in was from the surface, the older they were).

During the imperial period of the 19th century, European scientists also had the opportunity to conduct research in distant lands. One such individual was Charles Darwin, who had been recruited by Captain FitzRoy of the HMS Beagle to study the coastal land of South America and give geological advice.

Darwin’s discovery of giant fossils during the voyage helped to establish his reputation as a geologist, and his theorizing about the causes of their extinction led to his theory of evolution by natural selection, published in On the Origin of Species in 1859.

During the 19th century, the governments of several countries including Canada, Australia, Great Britain and the United States began funding geological surveys that would produce geological maps of vast areas of the countries. Thought largely motivated by territorial ambitions and resource exploitation, they did benefit the study of geology.

The Earth's Tectonic Plates. Credit: msnucleus.org
The Earth’s Tectonic Plates. Credit: msnucleus.org

By this time, the scientific consensus established the age of the Earth in terms of millions of years, and the increase in funding and the development of improved methods and technology helped geology to move farther away from dogmatic notions of the Earth’s age and structure.

By the early 20th century, the development of radiometric dating (which is used to determine the age of minerals and rocks), provided the necessary the data to begin getting a sense of the Earth’s true age. By the turn of the century, geologists now believed the Earth to be 2 billion years old, which opened doors for theories of continental movement during this vast amount of time.

In 1912, Alfred Wegener proposed the theory of Continental Drift, which suggested that the continents were joined together at a certain time in the past and formed a single landmass known as Pangaea. In accordance with this theory, the shapes of continents and matching coastline geology between some continents indicated they were once attached together.

The super-continent Pangea during the Permian period (300 - 250 million years ago). Credit: NAU Geology/Ron Blakey
The super-continent Pangea during the Permian period (300 – 250 million years ago). Credit: NAU Geology/Ron Blakey

Research into the ocean floor also led directly to the theory of Plate Tectonics, which provided the mechanism for Continental Drift. Geophysical evidence suggested lateral motion of continents and that oceanic crust is younger than continental crust. This geophysical evidence also spurred the hypothesis of paleomagnetism, the record of the orientation of the Earth’s magnetic field recorded in magnetic minerals.

Then there was the development of seismology, the study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies, in the early 20th century. By measuring the time of travel of refracted and reflected seismic waves, scientists were able to gradually infer how the Earth was layered and what lay deeper at its core.

For example, in 1910, Harry Fielding Ried put forward the “elastic rebound theory”, based on his studies of the 1906 San Fransisco earthquake. This theory, which stated that earthquakes occur when accumulated energy is released along a fault line, was the first scientific explanation for why earthquakes happen, and remains the foundation for modern tectonic studies.

Earth viewed from the Moon by the Apollo 11 spacecraft. Credit: NASA
Earth viewed from the Moon by the Apollo 11 spacecraft. Credit: NASA

Then in 1926, English scientist Harold Jeffreys claimed that below the crust, the core of the Earth is liquid, based on his study of earthquake waves. And then in 1937, Danish seismologist Inge Lehmann went a step further and determined that within the earth’s liquid outer core, there is a solid inner core.

By the latter half of the 20th century, scientists developed a comprehensive theory of the Earth’s structure and dynamics had formed. As the century played out, perspectives shifted to a more integrative approach, where geology and Earth sciences began to include the study of the Earth’s internal structure, atmosphere, biosphere and hydrosphere into one.

This was assisted by the development of space flight, which allowed for Earth’s atmosphere to be studied in detail, as well as photographs taken of Earth from space. In 1972, the Landsat Program, a series of satellite missions jointly managed by NASA and the U.S. Geological Survey, began supplying satellite images that provided geologically detailed maps, and have been used to predict natural disasters and plate shifts.

Earth’s Layers:

The Earth can be divided into one of two ways – mechanically or chemically. Mechanically – or rheologically, meaning the study of liquid states – it can be divided into the lithosphere, asthenosphere, mesospheric mantle, outer core, and the inner core. But chemically, which is the more popular of the two, it can be divided into the crust, the mantle (which can be subdivided into the upper and lower mantle), and the core – which can also be subdivided into the outer core, and inner core.

The inner core is solid, the outer core is liquid, and the mantle is solid/plastic. This is due to the relative melting points of the different layers (nickel–iron core, silicate crust and mantle) and the increase in temperature and pressure as depth increases. At the surface, the nickel-iron alloys and silicates are cool enough to be solid. In the upper mantle, the silicates are generally solid but localized regions of melt exist, leading to limited viscosity.

In contrast, the lower mantle is under tremendous pressure and therefore has a lower viscosity than the upper mantle. The metallic nickel–iron outer core is liquid because of the high temperature. However, the intense pressure, which increases towards the inner core, dramatically changes the melting point of the nickel–iron, making it solid.

The differentiation between these layers is due to processes that took place during the early stages of Earth’s formation (ca. 4.5 billion years ago). At this time, melting would have caused denser substances to sink toward the center while less-dense materials would have migrated to the crust. The core is thus believed to largely be composed of iron, along with nickel and some lighter elements, whereas less dense elements migrated to the surface along with silicate rock.

Earth’s Crust:

The crust is the outermost layer of the planet, the cooled and hardened part of the Earth that ranges in depth from approximately 5-70 km (~3-44 miles). This layer makes up only 1% of the entire volume of the Earth, though it makes up the entire surface (the continents and the ocean floor).

The Earth's layers (strata) shown to scale. Credit: pubs.usgs.gov
The Earth’s layers (strata) shown to scale. Credit: pubs.usgs.gov

The thinner parts are the oceanic crust, which underlies the ocean basins at a depth of 5-10 km (~3-6 miles), while the thicker crust is the continental crust. Whereas the oceanic crust is composed of dense material such as iron magnesium silicate igneous rocks (like basalt), the continental crust is less dense and composed of sodium potassium aluminum silicate rocks, like granite.

The uppermost section of the mantle (see below), together with the crust, constitutes the lithosphere – an irregular layer with a maximum thickness of perhaps 200 km (120 mi). Many rocks now making up Earth’s crust formed less than 100 million (1×108) years ago. However, the oldest known mineral grains are 4.4 billion (4.4×109) years old, indicating that Earth has had a solid crust for at least that long.

Upper Mantle:

The mantle, which makes up about 84% of Earth’s volume, is predominantly solid, but behaves as a very viscous fluid in geological time. The upper mantle, which starts at the “Mohorovicic Discontinuity” (aka. the “Moho” – the base of the crust) extends from a depth of 7 to 35 km (4.3 to 21.7 mi) downwards to a depth of 410 km (250 mi). The uppermost mantle and the overlying crust form the lithosphere, which is relatively rigid at the top but becomes noticeably more plastic beneath.

Compared to other strata, much is known about the upper mantle, thanks to seismic studies and direct investigations using mineralogical and geological surveys. Movement in the mantle (i.e. convection) is expressed at the surface through the motions of tectonic plates. Driven by heat from deeper in the interior, this process is responsible for Continental Drift, earthquakes, the formation of mountain chains, and a number of other geological processes.

Computer simulation of the Earth's field in a period of normal polarity between reversals.[1] The lines represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and vertical. The dense clusters of lines are within the Earth's core
Computer simulation of the Earth’s field in a period of normal polarity between reversals.  Credit: science.nasa.gov
The mantle is also chemically distinct from the crust, in addition to being different in terms of rock types and seismic characteristics. This is due in large part to the fact that the crust is made up of solidified products derived from the mantle, where the mantle material is partially melted and viscous. This causes incompatible elements to separate from the mantle, with less dense material floating upward and solidifying at the surface.

The crystallized melt products near the surface, upon which we live, are typically known to have a lower magnesium to iron ratio and a higher proportion of silicon and aluminum. These changes in mineralogy may influence mantle convection, as they result in density changes and as they may absorb or release latent heat as well.

In the upper mantle, temperatures range between 500 to 900 °C (932 to 1,652 °F). Between the upper and lower mantle, there is also what is known as the transition zone, which ranges in depth from 410-660 km (250-410 miles).

Lower Mantle:

The lower mantle lies between 660-2,891 km (410-1,796 miles) in depth. Temperatures in this region of the planet can reach over 4,000 °C (7,230 °F) at the boundary with the core, vastly exceeding the melting points of mantle rocks. However, due to the enormous pressure exerted on the mantle, viscosity and melting are very limited compared to the upper mantle. Very little is known about the lower mantle apart from that it appears to be relatively seismically homogeneous.

The internal structure of Earth. Credit: Wikipedia Commons/Kelvinsong
The internal structure of Earth. Credit: Wikipedia Commons/Kelvinsong

Outer Core:

The outer core, which has been confirmed to be liquid (based on seismic investigations), is 2300 km thick, extending to a radius of ~3,400 km. In this region, the density is estimated to be much higher than the mantle or crust, ranging between 9,900 and 12,200 kg/m3. The outer core is believed to be composed of 80% iron, along with nickel and some other lighter elements.

Denser elements, like lead and uranium, are either too rare to be significant or tend to bind to lighter elements and thus remain in the crust. The outer core is not under enough pressure to be solid, so it is liquid even though it has a composition similar to that of the inner core. The temperature of the outer core ranges from 4,300 K (4,030 °C; 7,280 °F) in the outer regions to 6,000 K (5,730 °C; 10,340 °F) closest to the inner core.

Because of its high temperature, the outer core exists in a low viscosity fluid-state that undergoes turbulent convection and rotates faster than the rest of the planet. This causes eddy currents to form in the fluid core, which in turn creates a dynamo effect that is believed to influence Earth’s magnetic field. The average magnetic field strength in Earth’s outer core is estimated to be 25 Gauss (2.5 mT), which is 50 times the strength of the magnetic field measured on Earth’s surface.

Inner Core:

Like the outer core, the inner core is composed primarily of iron and nickel and has a radius of ~1,220 km. Density in the core ranges between 12,600-13,000 kg/m³, which suggests that there must also be a great deal of heavy elements there as well – such as gold, platinum, palladium, silver and tungsten.

Artist’s illustration of Earht's core via Huff Post Science
Artist’s illustration of Earth’s core, inner core, and inner-inner core. Credit: Huff Post Science

The temperature of the inner core is estimated to be about 5,700 K (~5,400 °C; 9,800 °F). The only reason why iron and other heavy metals can be solid at such high temperatures is because their melting temperatures dramatically increase at the pressures present there, which ranges from about 330 to 360 gigapascals.

Because the inner core is not rigidly connected to the Earth’s solid mantle, the possibility that it rotates slightly faster or slower than the rest of Earth has long been considered. By observing changes in seismic waves as they passed through the core over the course of many decades, scientists estimate that the inner core rotates at a rate of one degree faster than the surface. More recent geophysical estimates place the rate of rotation between 0.3 to 0.5 degrees per year relative to the surface.

Recent discoveries also suggest that the solid inner core itself is composed of layers, separated by a transition zone about 250 to 400 km thick. This new view of the inner core, which contains an inner-inner core, posits that the innermost layer of the core measures 1,180 km (733 miles) in diameter, making it less than half the size of the inner core. It has been further speculated that while the core is composed of iron, it may be in a different crystalline structure that the rest of the inner core.

What’s more, recent studies have led geologists to conjecture that the dynamics of deep interior is driving the Earth’s inner core to expand at the rate of about 1 millimeter a year. This occurs mostly because the inner core cannot dissolve the same amount of light elements as the outer core.

The freezing of liquid iron into crystalline form at the inner core boundary produces residual liquid that contains more light elements than the overlying liquid. This in turn is believed to cause the liquid elements to become buoyant, helping to drive convection in the outer core. This growth is therefore likely to play an important role in the generation of Earth’s magnetic field by dynamo action in the liquid outer core. It also means that the Earth’s inner core, and the processes that drive it, are far more complex than previously thought!

Yes indeed, the Earth is a strange and mysteries place, titanic in scale as well as the amount of heat and energy that went into making it many billions of years ago. And like all bodies in our universe, the Earth is not a finished product, but a dynamic entity that is subject to constant change. And what we know about our world is still subject to theory and guesswork, given that we can’t examine its interior up close.

As the Earth’s tectonic plates continue to drift and collide, its interior continues to undergo convection, and its core continues to grow, who knows what it will look like eons from now? After all, the Earth was here long before we were, and will likely continue to be long after we are gone.

We have written many articles about Earth for Universe Today. Here’s are some Interesting Facts about Earth, and here’s one about the Earth’s inner inner core, and another about how minerals stop transferring heat at the core.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

If you’d like more info on Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an episode of Astronomy Cast all about Earth. Listen here, Episode 51: Earth.

See EPIC Views of Rotating Earth Daily from NASA’s New DSCOVR Observatory Website

At long last, beautiful new high resolution views of the rotating Earth can be seen daily by everyone at a new NASA website – all courtesy of images taken by NASA’s EPIC camera on board the Deep Space Climate Observatory (DSCOVR) spacecraft. And as seen in the time-lapse animation above, they provide a wonderful new asset for students everywhere to learn geography that’s just a finger tip away!

The EPIC camera, which stands for Earth Polychromatic Imaging Camera (EPIC), is located a million miles away on the DSCOVR real time space weather monitoring satellite and is designed to take full disk color images of the sunlit side of our home planet multiple times per day.

The EPIC NASA images are literally just a finger tip away, after a 17 year wait to get the satellite into the launch queue since it was first proposed by former VP Al Gore. They are all easily viewed at NASA’s new EPIC camera website which went online today, Monday, October 19, 2015.

To see the daily sequence of rotating images, visit the EPIC website link: http://epic.gsfc.nasa.gov/

This EPIC image was taken on Oct.17 and shows the Australian continent and a portion of Asia.

EPIC image taken on Oct. 17, 2015 showing the continent of Australia and a portion of Asia. Credit: NASA
EPIC image taken on Oct. 17, 2015 showing the continent of Australia and a portion of Asia. Credit: NASA

An annotated guide map illustration identifying the visible land masses accompanies each EPIC image and follows along as the Earth rotates daily.

What a great geography learning tool for student classrooms worldwide!

Annotated guide map identifying the visible land masses accompanies each EPIC image. Credit: NASA
Annotated guide map identifying the visible land masses accompanies each EPIC image. Credit: NASA

DSCOVR is a joint mission between NOAA, NASA, and the U.S Air Force (USAF) that is managed by NOAA. The satellite and science instruments were provided by NASA and NOAA.

EPIC is a four megapixel CCD camera and telescope mounted on DSCOVR and orbiting around the L1 Lagrange Point – a neutral gravity point that lies on the direct line between Earth and the sun.

NASA says that once per day they will post “at least a dozen new color images of Earth acquired from 12 to 36 hours earlier” taken by the agency’s EPIC camera. The EPIC images will be stored in an archive searchable by date and continent.

The image sequence will show “the Earth as it rotates, thus revealing the whole globe over the course of a day.”

“The effective resolution of the DSCOVR EPIC camera is somewhere between 6.2 and 9.4 miles (10 and 15 kilometers),” said Adam Szabo, DSCOVR project scientist at NASA’s Goddard Space Flight Center, Greenbelt, Maryland, in a statement.

“The color Earth images are created by combining three separate single-color images to create a photographic-quality image equivalent to a 12-megapixel camera. The camera takes a series of 10 images using different narrowband filters — from ultraviolet to near infrared — to produce a variety of science products. The red, green and blue channel images are used to create the color images. Each image is about 3 megabytes in size.”

EPIC will capture “a constant view of the fully illuminated Earth as it rotates, providing scientific observations of ozone, vegetation, cloud height and aerosols in the atmosphere.”

Technician works on NASA Earth science instruments and Earth imaging EPIC camera (white circle) housed on NOAA/NASA Deep Space Climate Observatory (DSCOVR) inside NASA Goddard Space Flight Center clean room in November 2014.  Credit: Ken Kremer/kenkremer.com
Technician works on NASA Earth science instruments and Earth imaging EPIC camera (white circle) housed on NOAA/NASA Deep Space Climate Observatory (DSCOVR) inside NASA Goddard Space Flight Center clean room in November 2014. Credit: Ken Kremer/kenkremer.com

The couch sized probe was launched atop a SpaceX Falcon 9 on Feb. 11, 2015 from Cape Canaveral, Florida, to start the million mile journey to its deep space observation post at L1. The rocket was funded by the USAF.

The primary goal of the $340 million DSCOVR satellite is to monitor the solar wind and aid very important forecasts of space weather at Earth from L1.

L1 is located 1.5 million kilometers (932,000 miles) sunward from Earth. At L1 the gravity between the sun and Earth is perfectly balanced and the DSCOVR satellite orbits about that spot just like a planet.

The mission is vital because its solar wind observations are crucial to maintaining accurate space weather forecasts to protect US infrastructure such as power grids, aviation, planes in flight, all types of Earth orbiting satellites for civilian and military needs, telecommunications, ISS astronauts and GPS systems.

This animation shows images of the far side of the moon, illuminated by the sun, as it crosses between the DISCOVR spacecraft's Earth Polychromatic Imaging Camera (EPIC) camera and telescope, and the Earth - one million miles away.  Credit: NASA/NOAA
This animation shows images of the far side of the moon, illuminated by the sun, as it crosses between the DISCOVR spacecraft’s Earth Polychromatic Imaging Camera (EPIC) camera and telescope, and the Earth – one million miles away. Credit: NASA/NOAA

DSCOVR was first proposed in 1998 by then US Vice President Al Gore as the low cost ‘Triana’ satellite to take near continuous views of the Earth’s entire globe to feed to the internet as a means of motivating students to study math and science.

It was also dubbed “Goresat.”

The probe was eventually resurrected and partially rebuilt at NASA Goddard Space Flight Center as a much more capable Earth science satellite that would also conduct the space weather observations.

But Triana was shelved for purely partisan political reasons and the satellite was placed into storage at NASA Goddard.

Thus the practical and teachable science and daily scenes of the gorgeously rotating Earth were lost – until now!

Former VP Al Gore was clearly delighted with today’s launch of NASA’s EPIC website in this pair of tweets:

“Today @NASA launched its site for #DSCOVR’s daily images. I look forward to seeing more from #DSCOVR,” tweeted Al Gore.

“DSCOVR’s site displaying new daily images of Earth from L1 was launched today! Congratulations to all those who made this happen!”

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

NOAA/NASA Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room. Solar wind instruments at right. DSCOVER will launch in February 2015 atop SpaceX Falcon 9 rocket.  Credit: Ken Kremer/kenkremer.com
NOAA/NASA Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room. Solar wind instruments at right. DSCOVER launched in February 2015 atop SpaceX Falcon 9 rocket. Credit: Ken Kremer/kenkremer.com
NOAA/NASA/USAF Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room.  Probe will launch in February atop SpaceX Falcon 9 rocket.  Credit: Ken Kremer - kenkremer.com
NOAA/NASA/USAF Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room. Probe launched in February 2015 atop SpaceX Falcon 9 rocket. Credit: Ken Kremer/kenkremer.com

Space Weather Storm Monitoring Satellite Blasts off for Deep Space on SpaceX Rocket

After a 17 year long wait, a new American mission to monitor intense solar storms and warn of impeding space weather disruptions to vital power grids, telecommunications satellites and public infrastructure was launched atop a SpaceX Falcon 9 on Wednesday, Feb. 11, from Cape Canaveral, Florida, to start a million mile journey to its deep space observation post.

The third time proved to be the charm when the Deep Space Climate Observatory, or DSCOVR science satellite lifted off at 6:03 p.m. EST Wednesday from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

The spectacular sunset blastoff came after two scrubs this week forced by a technical problem with the Air Force tracking radar and adverse weather on Sunday and Tuesday.

The $340 million DSCOVR has a critical mission to monitor the solar wind and aid very important forecasts of space weather at Earth at an observation point nearly a million miles from Earth. It will also take full disk color images of the sunlit side of Earth at least six times per day that will be publicly available and “wow” viewers.

Launch of NOAA DSCOVR satellite from Cape Canaveral Air Force Station on Feb. 11, 2015 to monitor solar storms and space weather.   Credit:  Julian Leek
Launch of NOAA DSCOVR satellite from Cape Canaveral Air Force Station on Feb. 11, 2015 to monitor solar storms and space weather. Credit: Julian Leek

The couch sized probe was targeted to the L1 Lagrange Point, a neutral gravity point that lies on the direct line between Earth and the sun located 1.5 million kilometers (932,000 miles) sunward from Earth. At L1 the gravity between the sun and Earth is perfectly balanced and the satellite will orbit about that spot just like a planet.

L1 is a perfect place for the science because it lies outside Earth’s magnetic environment. The probe will measure the constant stream of solar wind particles from the sun as they pass by.

The DSCOVR spacecraft (3-axis stabilized, 570 kg) will be delivered to the Sun-Earth L1 point, 1.5 million km (1 million miles) from the Earth, directly in front of the Sun. A Halo (Lissajous) orbit will stabilize the craft's position around the L1 point while keeping it outside the radio noise emanating from the Sun. (Illustratin Credit: NASA)
The DSCOVR spacecraft (3-axis stabilized, 570 kg) will be delivered to the Sun-Earth L1 point, 1.5 million km (1 million miles) from the Earth, directly in front of the Sun. A Halo (Lissajous) orbit will stabilize the craft’s position around the L1 point while keeping it outside the radio noise emanating from the Sun. (Illustratin Credit: NASA)

DSCOVR is a joint mission between NOAA, NASA, and the U.S Air Force (USAF) that will be managed by NOAA. The satellite and science instruments are provided by NASA and NOAA. The rocket was funded by the USAF.

The mission is vital because its solar wind observations are crucial to maintaining accurate space weather forecasts to protect US infrastructure such as power grids, aviation, planes in flight, all types of Earth orbiting satellites for civilian and military needs, telecommunications, ISS astronauts and GPS systems.

It will take about 150 days to reach the L1 point and complete satellite and instrument checkouts.

DSCOVR will then become the first operational space weather mission to deep space and function as America’s primary warning system for solar magnetic storms.

It will replace NASA’s aging Advanced Composition Explorer (ACE) satellite which is nearly 20 years old and far beyond its original design lifetime.

“DSCOVR is the latest example of how NASA and NOAA work together to leverage the vantage point of space to both understand the science of space weather and provide direct practical benefits to us here on Earth,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington.

DSCOVR was first proposed in 1998 by then US Vice President Al Gore as the low cost ‘Triana’ satellite to take near continuous views of the Earth’s entire globe to feed to the internet as a means of motivating students to study math and science. It was eventually built as a much more capable Earth science satellite that would also conduct the space weather observations.

But Triana was shelved for purely partisan political reasons and the satellite was placed into storage at NASA Goddard and the science was lost until now.

DSCOVR mission logo.  Credit: NOAA/NASA/U.S. Air Force
DSCOVR mission logo. Credit: NOAA/NASA/U.S. Air Force

DSCOVR is equipped with a suite of four continuously operating solar science and Earth science instruments from NASA and NOAA.

It will make simultaneous scientific observations of the solar wind and the entire sunlit side of Earth.

The 750-kilogram (1250 pound) DSCOVR probe measures 54 inches by 72 inches.

Technician works on NASA Earth science instruments and Earth imaging EPIC camera (white circle) housed on NOAA/NASA Deep Space Climate Observatory (DSCOVR) inside NASA Goddard Space Flight Center clean room in November 2014.  Credit: Ken Kremer/kenkremer.com/AmericaSpace
Technician works on NASA Earth science instruments and Earth imaging EPIC camera (white circle) housed on NOAA/NASA Deep Space Climate Observatory (DSCOVR) inside NASA Goddard Space Flight Center clean room in November 2014. Credit: Ken Kremer/kenkremer.com/AmericaSpace

The two Earth science instruments from NASA are the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology Advanced Radiometer (NISTAR).

EPIC will provide true color spectral images of the entire sunlit face of Earth at least six times per day, as viewed from an orbit around L1. They will be publically available within 24 hours via NASA Langley.

It will view the full disk of the entire sunlit Earth from sunrise to sunset and collect a variety of science measurements including on ozone, aerosols, dust and volcanic ash, vegetation properties, cloud heights and more.

Listen to my post launch interview with the BBC about DSCOVR and ESA’s successful IXV launch on Feb. 11.

A secondary objective by SpaceX to recover the Falcon 9 first stage booster on an ocean going barge had to be skipped due to very poor weather and very high waves in the Atlantic Ocean making a safe landing impossible. The stage did successfully complete a soft landing in the ocean.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

NOAA/NASA Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room. Solar wind instruments at right. DSCOVER will launch in February 2015 atop SpaceX Falcon 9 rocket.  Credit: Ken Kremer/kenkremer.com/AmericaSpace
NOAA/NASA Deep Space Climate Observatory (DSCOVR) undergoes processing in NASA Goddard Space Flight Center clean room. Solar wind instruments at right. DSCOVER will launch in February 2015 atop SpaceX Falcon 9 rocket. Credit: Ken Kremer/kenkremer.com/AmericaSpace
Launch of NOAA DSCOVR satellite from Cape Canaveral Air Force Station on Feb. 11, 2015 to monitor solar storms and space weather.   Credit:  John Studwell
Launch of NOAA DSCOVR satellite from Cape Canaveral Air Force Station on Feb. 11, 2015 to monitor solar storms and space weather. Credit: John Studwell
Prelaunch view of SpaceX rocket on Cape Canaveral launch pad taken from LC-39 at the Kennedy Space Center.  Credit: Chuck Higgins
Prelaunch view of SpaceX rocket on Cape Canaveral launch pad taken from LC-39 at the Kennedy Space Center. Credit: Chuck Higgins

NASA Launches Revolutionary Earth Science Satellite Measuring Soil Moisture Cycle

NASA’s Soil Moisture Active Passive (SMAP) observatory, on a United Launch Alliance Delta II rocket, is seen after the mobile service tower was rolled back Friday, Jan. 30 at Space Launch Complex 2, Vandenberg Air Force Base, Calif.
Image Credit: NASA/Bill Ingalls
Story updated[/caption]

At dawn this morning (Jan. 31) NASA launched an advanced Earth science satellite aimed at making measurements of our planet’s surface soil moisture and freeze/thaw states from space that will revolutionize our understanding of the water, energy, and carbon cycles driving all life on Earth, aid weather forecasting and improve climate change models.

NASA’s new Soil Moisture Active Passive (SMAP) observatory thundered off the pad at 6:22 a.m. PST (9:22 a.m. EST) Saturday atop a two stage United Launch Alliance Delta II rocket from Space Launch Complex 2 on Vandenberg Air Force Base, California.

The $916 million satellite successfully separated from the rocket’s second stage some 57 minutes after the flawless liftoff and was injected into an initial 411- by 425-mile (661- by 685-kilometer) orbit. The spacecraft then deployed its solar arrays and telemetry indicated it was in excellent health.

“We’re in contact with SMAP and everything looks good right now,” NASA Launch Manager Tim Dunn said.

“Deployment of the solar arrays is underway. We just couldn’t be happier.”

SMAP separated from the second stage while pointed toward the sun as seen in the video below from a rocket mounted camera:

Video Caption: A camera on the second stage of the Delta II rocket captured this footage as the SMAP spacecraft pushed itself away from the rocket to complete the delivery of the Earth-observing spacecraft to its proper orbit following Jan. 31, 2015 liftoff. Credit: NASA TV/ULA

SMAP is NASA’s 1st Earth observing satellite designed to make high resolution global observations of Earth’s vital surface soil moisture content and freeze/thaw cycle just below your feet. It will aid global forecasting and have broad applications for science and society.

SMAP’s combined radar and radiometer instruments will peer into the top 2 inches (5 centimeters) of soil, through clouds and moderate vegetation cover, day and night, to produce the highest-resolution, most accurate soil moisture maps ever obtained from space, says NASA.

The blastoff of SMAP successfully concluded NASA’s ambitious plans to launch a record breaking total of five Earth science satellites in less than a year’s time.

“The launch of SMAP completes an ambitious 11-month period for NASA that has seen the launch of five new Earth-observing space missions to help us better understand our changing planet,” said NASA Administrator Charles Bolden.

“Scientists and policymakers will use SMAP data to track water movement around our planet and make more informed decisions in critical areas like agriculture and water resources.”

Artist's rendering of the Soil Moisture Active Passive satellite. The width of the region scanned on Earth’s surface during each orbit is about 620 miles (1,000 kilometers).  Image credit: NASA/JPL-Caltech
Artist’s rendering of the Soil Moisture Active Passive satellite. The width of the region scanned on Earth’s surface during each orbit is about 620 miles (1,000 kilometers). Image credit: NASA/JPL-Caltech

SMAP is projected to last for at least a three year primary mission.

The prior NASA Earth science instrument launched was the Cloud Aerosol Transport System (CATS) payload hauled to space by the SpaceX CRS-4 Dragon on Jan. 10, 2015 and recently installed on the exterior of the ISS. Read my CATS installation story – here.

The three earlier NASA Earth science missions launched over the past year included ISS-RapidScat in September 2014, the Global Precipitation Measurement (GPM) Core Observatory, a joint mission with the Japan Aerospace Exploration Agency, in February 2014, and the Orbiting Carbon Observatory-2 (OCO-2) carbon observatory in July 2014.

“Congratulations to the NASA Launch Services Program team, JPL and all of our mission partners on today’s successful launch of the SMAP satellite,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs.

“It is our honor to launch this important Earth science mission to help scientists observe and predict natural hazards, and improve our understanding of Earth’s water, energy and carbon cycles.”

SMAP will provide high-resolution, space-based measurements of soil moisture and its state — frozen or thawed — a new capability that will allow scientists to better predict natural hazards of extreme weather, climate change, floods and droughts, and help reduce uncertainties in our understanding of Earth’s water, energy and carbon cycles, according to a NASA description.

The mission will map the entire globe every two to three days for at least three years and provide the most accurate and highest-resolution maps of soil moisture ever obtained. The spacecraft’s final circular polar orbit will be 426 miles (685 kilometers), at an inclination of 98.1 degrees. The spacecraft will orbit Earth once every 98.5 minutes and repeat the same ground track every eight days.

“All subsystems are being powered on and checked out as planned,” Kent Kellogg, the SMAP project manager, during a post-launch press conference.

“Communications, guidance and control, computers and power are all operating nominally.”

The observatory is in excellent health. Its instruments will be turned on in 11 days.

Today’s blastoff of SMAP marks ULA’s second successful launch this month as well as the second of 13 planned for 2015. ULA’s first launch of 2015 was MUOS-3 from Cape Canaveral on Jan. 20.

ULA’s next launch involves NASA’s Magnetospheric Multiscale Mission (MMS) to study Earth’s magnetic reconnection. It is scheduled for launch on an Atlas V 421 booster on March 12 from Cape Canaveral. See my up close visit with MMS and NASA Administrator Charles Bolden at NASA Goddard Space Flight Center detailed in my story – here.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

NASA’s RapidScat Ocean Wind Watcher Starts Earth Science Operations at Space Station

Barely two months after being launched to the International Space Station (ISS), NASA’s first science payload aimed at conducting Earth science from the station’s exterior has started its ocean wind monitoring operations two months ahead of schedule.

Data from the ISS Rapid Scatterometer, or ISS-RapidScat, payload is now available to the world’s weather and marine forecasting agencies following the successful completion of check out and calibration activities by the mission team.

Indeed it was already producing high quality, usable data following its power-on and activation at the station in late September and has monitored recent tropical cyclones in the Atlantic and Pacific Oceans prior to the end of the current hurricane season.

RapidScat is designed to monitor ocean winds for climate research, weather predictions, and hurricane monitoring for a minimum mission duration of two years.

“RapidScat is a short mission by NASA standards,” said RapidScat Project Scientist Ernesto Rodriguez of JPL.

“Its data will be ready to help support U.S. weather forecasting needs during the tail end of the 2014 hurricane season. The dissemination of these data to the international operational weather and marine forecasting communities ensures that RapidScat’s benefits will be felt throughout the world.”

ISS-RapidScat instrument, shown in this artist's rendering, was launched to the International Space Station aboard the SpaceX CRS-4 mission on Sept. 21, 2014 and attached at ESA’s Columbus module.  It will measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. Credit: NASA/JPL-Caltech/Johnson Space Center.
ISS-RapidScat instrument, shown in this artist’s rendering, was launched to the International Space Station aboard the SpaceX CRS-4 mission on Sept. 21, 2014, and attached at ESA’s Columbus module. It will measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. Credit: NASA/JPL-Caltech/Johnson Space Center.

The 1280 pound (580kilogram) experimental instrument was developed by NASA’s Jet Propulsion Laboratory. It’s a cost-effective replacement to NASA’s former QuikScat satellite.

The $26 million remote sensing instrument uses radar pulses reflected from the ocean’s surface at different angles to calculate the speed and direction of winds over the ocean for the improvement of weather and marine forecasting and hurricane monitoring.

The RapidScat, payload was hauled up to the station as part of the science cargo launched aboard the commercial SpaceX Dragon CRS-4 cargo resupply mission that thundered to space on the company’s Falcon 9 rocket from Space Launch Complex-40 at Cape Canaveral Air Force Station in Florida on Sept. 21.

ISS-RapidScat is NASA’s first research payload aimed at conducting near global Earth science from the station’s exterior and will be augmented with others in coming years.

ISS-RapidScat viewed the winds within post-tropical cyclone Nuri as it moved parallel to Japan on Nov. 6, 2014 05:30 UTC. Image Credit: NASA/JPL-Caltech
ISS-RapidScat viewed the winds within post-tropical cyclone Nuri as it moved parallel to Japan on Nov. 6, 2014, 05:30 UTC. Image Credit: NASA/JPL-Caltech

It was robotically assembled and attached to the exterior of the station’s Columbus module using the station’s robotic arm and DEXTRE manipulator over a two day period on Sept 29 and 30.

Ground controllers at Johnson Space Center intricately maneuvered DEXTRE to pluck RapidScat and its nadir adapter from the unpressurized trunk section of the Dragon cargo ship and attached it to a vacant external mounting platform on the Columbus module holding mechanical and electrical connections.

The nadir adapter orients the instrument to point its antennae at Earth.

The couch sized instrument and adapter together measure about 49 x 46 x 83 inches (124 x 117 x 211 centimeters).

“The initial quality of the RapidScat wind data and the timely availability of products so soon after launch are remarkable,” said Paul Chang, ocean vector winds science team lead at NOAA’s National Environmental Satellite, Data and Information Service (NESDIS)/Center for Satellite Applications and Research (STAR), Silver Spring, Maryland.

“NOAA is looking forward to using RapidScat data to help support marine wind and wave forecasting and warning, and to exploring the unique sampling of the ocean wind fields provided by the space station’s orbit.”

A SpaceX Falcon 9 rocket carrying a Dragon cargo capsule packed with science experiments and station supplies blasts off from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida, at 1:52 a.m. EDT on Sept. 21, 2014 bound for the ISS.  Credit: Ken Kremer/kenkremer.com
A SpaceX Falcon 9 rocket carrying a Dragon cargo capsule packed with science experiments and station supplies blasts off from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida, at 1:52 a.m. EDT on Sept. 21, 2014, bound for the ISS. Credit: Ken Kremer/kenkremer.com

This has been a banner year for NASA’s Earth science missions. At least five missions will be launched to space within a 12 month period, the most new Earth-observing mission launches in one year in more than a decade.

ISS-RapidScat is the third of five NASA Earth science missions scheduled to launch over a year.

NASA has already launched the of the Global Precipitation Measurement (GPM) Core Observatory, a joint mission with the Japan Aerospace Exploration Agency, in February and the Orbiting Carbon Observatory-2 (OCO-2) carbon observatory in July 2014.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer