Another Juno Flyby, Another Amazing Sequence of Images of Jupiter

In July of 2016, the Juno spacecraft established orbit around Jupiter, becoming the first spacecraft since the Galileo probe to study the planet directly. Since that time, the probe has been sending back vital information about Jupiter’s atmosphere, magnetic field and weather patterns. With every passing orbit – known as perijoves, which take place every 53 days – the probe has revealed more exciting things about this gas giant.
Continue reading “Another Juno Flyby, Another Amazing Sequence of Images of Jupiter”

Pluto is What You Get When a Billion Comets Smash Together

Pluto has been the focus of a lot of attention for more than a decade now. This began shortly after the discovery of Eris in the Kuiper Belt, one of many Kuiper Belt Objects (KBOs) that led to the “Great Planetary Debate” and the 2006 IAU Resolution. Interest in Pluto also increased considerably thanks to the New Horizons mission, which conducted the first flyby of this “dwarf planet” in July of 2015.

The data this mission provided on Pluto is still proving to be a treasure trove for astronomers, allowing for new discoveries about Pluto’s surface, composition, atmosphere, and even formation. For instance, a new study produced by researchers from the Southwest Research Institute (and supported by NASA Rosetta funding) indicates that Pluto may have formed from a billion comets crashing together.

The study, titled “Primordial N2 provides a cosmochemical explanation for the existence of Sputnik Planitia, Pluto“, recently appeared in the scientific journal Icarus. The study was authored by Dr. Christopher R. Glein – a researcher with the Southwest Research Institute’s Space Science and Engineering Division – and Dr. J. Hunter Waite Jr, an SwRI program director.

The first Kuiper Belt is home to more than 100,000 asteroids and comets there over 62 miles (100 km) across. Credit: JHUAPL

The origin of Pluto is something that astronomers have puzzled over for some time. An early hypothesis was that it was an escaped moon of Neptune that had been knocked out of orbit by Neptune’s current largest moon, Triton. However, this theory was disproven after dynamical studies showed that Pluto never approaches Neptune in its orbit. With the discovery of the Kuiper Belt in 1992, the true of origin of Pluto began to become clear.

Essentially, while Pluto is the largest object in the Kuiper Belt, it is similar in orbit and composition to the icy objects that surround it. On occasion, some of these objects are kicked out of the Kuiper Belt and become long-period comets in the Inner Solar System. To determine if Pluto formed from billions of KBOs, Dr. Glein and Dr. Waite Jr. examined data from the New Horizons mission on the nitrogen-rich ice in Sputnik Planitia.

This large glacier forms the left lobe of the bright Tombaugh Regio feature on Pluto’s surface (aka. Pluto’s “Heart”). They then compared this to data obtained by the NASA/ESA Rosetta mission, which studied the comet 67P/Churyumov–Gerasimenko (67P) between 2014 and 2016. As Dr. Glein explained:

“We’ve developed what we call ‘the giant comet’ cosmochemical model of Pluto formation. We found an intriguing consistency between the estimated amount of nitrogen inside the glacier and the amount that would be expected if Pluto was formed by the agglomeration of roughly a billion comets or other Kuiper Belt objects similar in chemical composition to 67P, the comet explored by Rosetta.”

New Horizon’s July 2015 flyby of Pluto captured this iconic image of the heart-shaped region called Tombaugh Regio. Credit: NASA/JHUAPL/SwRI

This research also comes up against a competing theory, known as the “solar model”. In this scenario, Pluto formed from the very cold ices that were part of the protoplanetary disk, and would therefore have a chemical composition that more closely matches that of the Sun. In order to determine which was more likely, scientists needed to understand not only how much nitrogen is present at Pluto now (in its atmosphere and glaciers), but how much could have leaked out into space over the course of eons.

They then needed to come up with an explanation for the current proportion of carbon monoxide to nitrogen. Ultimately, the low abundance of carbon monoxide at Pluto could only be explained by burial in surface ices or destruction from liquid water. In the end, Dr. Glein and Dr. Waite Jr.’s research suggests that Pluto’s initial chemical makeup, which was created by comets, was modified by liquid water, possibly in the form of a subsurface ocean.

“This research builds upon the fantastic successes of the New Horizons and Rosetta missions to expand our understanding of the origin and evolution of Pluto,” said Dr. Glein. “Using chemistry as a detective’s tool, we are able to trace certain features we see on Pluto today to formation processes from long ago. This leads to a new appreciation of the richness of Pluto’s ‘life story,’ which we are only starting to grasp.”

While the research certainly offers an interesting explanation for how Pluto formed, the solar model still satisfies some criteria. In the end, more research will be needed before scientists can conclude how Pluto formed. And if data from the New Horizons or Rosetta missions should prove insufficient, perhaps another to New Frontiers mission to Pluto will solve the mystery!

Further Reading: SwRI, Icarus

NASA’s Experimental Hurricane Monitoring Fleet Launched by Pegasus rocket

Launch of the Orbital ATK Pegasus XL rocket carrying NASA’s CYGNSS spacecraft at 8:37 a.m. EST on Dec. 15, 2016.  Credit: NASA TV/Ken Kremer
Launch of the Orbital ATK Pegasus XL rocket carrying NASA’s CYGNSS spacecraft at 8:37 a.m. EST on Dec. 15, 2016. Credit: NASA TV/Ken Kremer

KENNEDY SPACE CENTER, FL – NASA’s constellation of experimental hurricane monitoring CYGNSS microsatellites was successfully air launched by the unique Orbital ATK winged Pegasus rocket on Thursday, Dec 15 – opening a new era in weather forecasters ability to measure the buildup of hurricane intensity in the tropics from orbit that will eventually help save lives and property from impending destructive storms here on Earth.

The agency’s innovative Cyclone Global Navigation Satellite System (CYGNSS) earth science mission was launched at 8:37 a.m. EST, Dec. 15, aboard a commercially developed Orbital ATK Pegasus XL rocket from a designated point over the Atlantic Ocean off the east coast of Florida.

Officials just announced this morning Dec. 16 that the entire fleet is operating well.

“NASA confirmed Friday morning that all eight spacecraft of its latest Earth science mission are in good shape.”

“The launch of CYGNSS is a first for NASA and for the scientific community,” said Thomas Zurbuchen, associate administrator for the agency’s Science Mission Directorate in Washington.

“As the first orbital mission in our Earth Venture program, CYGNSS will make unprecedented measurements in the most violent, dynamic, and important portions of tropical storms and hurricanes.”

An Orbital ATK L-1011 “Stargazer” aircraft carrying a Pegasus XL rocket with NASA’s CYGNSS spacecraft takes off from the Skid Strip at Cape Canaveral Air Force Station, Florida on Dec. 15, 2016 and successfully launches the spacecraft. Credit: Ken Kremer/kenkremer.com
An Orbital ATK L-1011 “Stargazer” aircraft carrying a Pegasus XL rocket with NASA’s CYGNSS spacecraft takes off from the Skid Strip at Cape Canaveral Air Force Station, Florida on Dec. 15, 2016 and successfully launches the spacecraft. Credit: Ken Kremer/kenkremer.com

Late Thursday, NASA announced that contact had been made with the entire fleet of eight small satellites after they had been successfully deployed and safely delivered to their intended position in low Earth orbit.

“We have successfully contacted each of the 8 observatories on our first attempt,” announced Chris Ruf, CYGNSS principal investigator with the Department of Climate and Space Sciences and Engineering at the University of Michigan.

“This bodes very well for their health and “status, which is the next thing we will be carefully checking with the next contacts in the coming days.”

The three stage Pegasus XL rocket housing the CYGNSS earth science payload inside the payload fairing had been carried aloft to 39,000 feet by an Orbital ATK L-1011 Tristar and dropped from the aircrafts belly for an air launch over the Atlantic Ocean and about 110 nautical miles east-northeast of Daytona Beach.

The Orbital ATK Pegasus XL rocket with NASA’s CYGNSS hurricane observing microsatellites  is attached to the belly of the Stargazer L-1011 as technicians work at the Skid Strip at Cape Canaveral Air Force Station in Florida.  It launched the payload to orbit on Dec. 15, 2016.  Credit: Ken Kremer/kenkremer.com
The Orbital ATK Pegasus XL rocket with NASA’s CYGNSS hurricane observing microsatellites is attached to the belly of the Stargazer L-1011 as technicians work at the Skid Strip at Cape Canaveral Air Force Station in Florida. It launched the payload to orbit on Dec. 15, 2016. Credit: Ken Kremer/kenkremer.com

The L-1011 nicknamed Stargazer took off at about 7:30 a.m. EST from NASA’s Skid Strip on Cape Canaveral Air Force Station in Florida as the media including myself watched the events unfold under near perfect Sunshine State weather with brilliantly clear blue skies.

After flying to the dropbox point – measuring about 40-miles by 10-miles (64-kilometers by 16-kilometers) – the Pegasus rocket was dropped from the belly, on command by the pilot, for a short freefall of about 5 seconds to initiate the launch sequence and engine ignition.

Pegasus launches horizontally in midair with ignition of the first stage engine burn, and then tilts up to space to begin the approximate ten minute trek to LEO.

The rocket launch and satellite release when exactly as planned with no hiccups.

It’s a beautiful day, with gorgeous weather,” said NASA CYGNSS launch director Tim Dunn. “We had a nominal flyout, and all three stages performed beautifully. We had no issues at all with launch vehicle performance.”

Deployment of the first pair of CYGNSS satellites in the eight satellite fleet started just 13 minutes after launch. The other six followed sequentially staged some 30 seconds apart.

“It’s a great event when you have a successful spacecraft separation – and with eight microsatellites, you get to multiply that times eight,” Dunn added.

“The deployments looked great — right on time,” said John Scherrer, CYGNSS Project Manager at the Southwest Research Institute and today’s CYGNSS mission manager, soon after launch.

“We think everything looks really, really good. About three hours after launch we’ll attempt first contact, and after that, we’ll go through a series of four contacts where we hit two [observatories] each time, checking the health and status of each spacecraft,” Scherrer added several prior to contact..

CYGNSS small satellite constellation launch came after a few days postponement due to technical issues following an aborted attempt on Monday, when the release mechanism failed and satellite parameter issues cropped up on Tuesday, both of which were rectified.

NASA’s innovative Cyclone Global Navigation Satellite System (CYGNSS) mission is expected to revolutionize hurricane forecasting by measuring the intensity buildup for the first time.

“The CYGNSS constellation consists of eight microsatellite observatories that will measure surface winds in and near a hurricane’s inner core, including regions beneath the eyewall and intense inner rainbands that previously could not be measured from space,” according to a NASA factsheet.

CYGNSS is an experimental mission to demonstrate proof-of-concept that could eventually turn operational in a future follow-up mission if the resulting data returns turn out as well as the researchers hope.

The CYGNSS constellation of 8 identical satellites works in coordination with the Global Positioning System (GPS) satellite constellation.

The eight satellite CYGNSS fleet “will team up with the Global Positioning System (GPS) constellation to measure wind speeds over Earth’s oceans and air-sea interactions, information expected to help scientists better understand tropical cyclones, ultimately leading to improved hurricane intensity forecasts.”

They will receive direct and reflected signals from GPS satellites.

“The direct signals pinpoint CYGNSS observatory positions, while the reflected signals respond to ocean surface roughness, from which wind speed is retrieved.”

This schematic outlines the key launch events:

Schematic of Orbital ATK L-1011 aircraft and Pegasus XL rocket air drop launch of NASA’s CYGNSS microsatellite fleet.  Credit: Orbital ATK
Schematic of Orbital ATK L-1011 aircraft and Pegasus XL rocket air drop launch of NASA’s CYGNSS microsatellite fleet. Credit: Orbital ATK

The $157 million fleet of eight identical spacecraft comprising the Cyclone Global Navigation Satellite System (CYGNSS) system were all delivered to low Earth orbit by the Orbital ATK Pegasus XL rocket.

The nominal mission lifetime for CYGNSS is two years but the team says they could potentially last as long as five years or more if the spacecraft continue functioning.

Artist's concept of the deployment of the eight Cyclone Global Navigation Satellite System (CYGNSS) microsatellite observatories in space.  Credits: NASA
Artist’s concept of the deployment of the eight Cyclone Global Navigation Satellite System (CYGNSS) microsatellite observatories in space. Credits: NASA

Pegasus launches from the Florida Space Coast are infrequent. The last once took place over 13 years ago in late April 2003 for the GALEX mission.

Typically they take place from Vandenberg Air Force Base in California or the Reagan Test Range on the Kwajalein Atoll.

An Orbital ATK L-1011 “Stargazer” aircraft carrying a Pegasus XL rocket with NASA’s CYGNSS spacecraft takes off from the Skid Strip at Cape Canaveral Air Force Station, Florida on Dec. 12, 2016. Credit: Ken Kremer/kenkremer.com
An Orbital ATK L-1011 “Stargazer” aircraft carrying a Pegasus XL rocket with NASA’s CYGNSS spacecraft takes off from the Skid Strip at Cape Canaveral Air Force Station, Florida on Dec. 12, 2016. Credit: Ken Kremer/kenkremer.com

CYGNSS counts as the 20th Pegasus mission for NASA and the 43rd mission overall for Orbital ATK.

The CYGNSS spacecraft were built by Southwest Research Institute in San Antonio, Texas.

The solar panels and spacecraft dispenser were built by Sierra Nevada Corporation (SNC).

Each one weighs approx 29 kg. The deployed solar panels measure 1.65 meters in length.

The solar panels measure 5 feet in length and will be deployed within about 15 minutes of launch.

“We are thrilled to be a part of a project that helps gain better hurricane data that can eventually help keep a lot of people safe, but from a business side, we are also glad we could help SwRI achieve their mission requirements with better performance and lower cost and risk,” said Bryan Helgesen, director of strategy and business development for Space Technologies in SNC’s Space Systems business area, in a statement.

Rear view into the first stage engine of Orbital ATK Pegasus XL rocket that will launch NASA's CYGNSS experimental hurricane observation payload on Dec. 14, 2016. They are mated to the bottom of the Orbital ATK L-1011 Stargazer aircraft at the Skid Strip at Cape Canaveral Air Force Station in Florida.  Credit: Ken Kremer/kenkremer.com
Rear view into the first stage engine of Orbital ATK Pegasus XL rocket that will launch NASA’s CYGNSS experimental hurricane observation payload on Dec. 14, 2016. They are mated to the bottom of the Orbital ATK L-1011 Stargazer aircraft at the Skid Strip at Cape Canaveral Air Force Station in Florida. Credit: Ken Kremer/kenkremer.com

The Space Physics Research Laboratory at the University of Michigan College of Engineering in Ann Arbor leads overall mission execution in partnership with the Southwest Research Institute in San Antonio, Texas.

The Climate and Space Sciences and Engineering Department at the University of Michigan leads the science investigation, and the Earth Science Division of NASA’s Science Mission Directorate oversees the mission.

The Orbital ATK L-1011 Stargazer aircraft at the Skid Strip at Cape Canaveral Air Force Station in Florida. Attached beneath the Stargazer is the Orbital ATK Pegasus XL with NASA's CYGNSS payload on board, being processed for launch on Dec. 12, 2016.  Credit: Ken Kremer/kenkremer.com
The Orbital ATK L-1011 Stargazer aircraft at the Skid Strip at Cape Canaveral Air Force Station in Florida. Attached beneath the Stargazer is the Orbital ATK Pegasus XL with NASA’s CYGNSS payload on board, being processed for launch on Dec. 12, 2016. Credit: Ken Kremer/kenkremer.com

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

Ken Kremer

An Orbital ATK technician checks the installation of two of the eight the CYGNSS microsatellites on their deployment module at Vandenberg Air Force Base in California.  Credits: Photo credit: USAF
An Orbital ATK technician checks the installation of two of the eight the CYGNSS microsatellites on their deployment module at Vandenberg Air Force Base in California. Credits: Photo credit: USAF

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Scientists Assemble Fresh Global Map of Pluto Comprising Sharpest Flyby Images

NASA’s New Horizons mission science team has produced this updated panchromatic (black-and-white) global map of Pluto. The map includes all resolved images of Pluto’s surface acquired at pixel resolutions ranging from 18 miles (30 kilometers) on the Charon-facing hemisphere (left and right edges of the map) to 770 feet (235 meters) on the hemisphere facing New Horizons during the closest approach on July 14, 2015 (map center).  Credits: NASA/JHUAPL/SWRI
NASA’s New Horizons mission science team has produced this updated panchromatic (black-and-white) global map of Pluto. Credits: NASA/JHUAPL/SWRI

The science team leading NASA’s New Horizons mission that unveiled the true nature of Pluto’s long hidden looks during the history making maiden close encounter last July, have published a fresh global map that offers the sharpest and most spectacular glimpse yet of the mysterious, icy world.

The newly updated global Pluto map is comprised of all the highest resolution images transmitted back to Earth thus far and provides the best perspective to date.

Click on the lead image above to enjoy Pluto revealed at its finest thus far. Click on this link to view the highest resolution version.

Prior to the our first ever flyby of the Pluto planetary system barely 8 months ago, the planet was nothing more than a fuzzy blob with very little in the way of identifiable surface features – even in the most powerful telescopic views lovingly obtained from the Hubble Space Telescope (HST).

Dead center in the new map is the mesmerizing heart shaped region informally known as Tombaugh Regio, unveiled in all its glory and dominating the diminutive world.

The panchromatic (black-and-white) global map of Pluto published by the team includes the latest images received as of less than one week ago on April 25.

The images were captured by New Horizons’ high resolution Long Range Reconnaissance Imager (LORRI).

The science team is working on assembling an updated color map.

During its closest approach at approximately 7:49 a.m. EDT (11:49 UTC) on July 14, 2015, the New Horizons spacecraft swoop to within about 12,500 kilometers (nearly 7,750 miles) of Pluto’s surface and about 17,900 miles (28,800 kilometers) from Charon, the largest moon.

The map includes all resolved images of Pluto’s surface acquired in the final week of the approach period ahead of the flyby starting on July 7, and continuing through to the day of closest approach on July 14, 2015 – and transmitted back so far.

The pixel resolutions are easily seen to vary widely across the map as you scan the global map from left to right – depending on which Plutonian hemisphere was closest to the spacecraft during the period of close flyby.
They range from the highest resolution of 770 feet (235 meters), at center, to 18 miles (30 kilometers) at the far left and right edges.

The Charon-facing hemisphere (left and right edges of the map) had a pixel resolution of 18 miles (30 kilometers).

“This non-encounter hemisphere was seen from much greater range and is, therefore, in far less detail,” noted the team.

However the hemisphere facing New Horizons during the spacecraft’s closest approach on July 14, 2015 (map center) had a far higher pixel resolution reaching to 770 feet (235 meters).

Coincidentally and fortuitously the spectacularly diverse terrain of Tombaugh Regio and the Sputnik Planum area of the hearts left ventricle with ice flows and volcanoes, mountains and river channels was in the region facing the camera and sports the highest resolution imagery.

See below a newly released shaded relief map of Sputnik Planum.

This new shaded relief view of the region surrounding the left side of Pluto’s heart-shaped feature – informally named Sputnik Planum – shows that the vast expanse of the icy surface is on average 2 miles (3 kilometers) lower than the surrounding terrain.  Angular blocks of water ice are “floating” in the bright deposits of softer, denser solid nitrogen.   Credits:  NASA/JHUAPL/SwRI
This new shaded relief view of the region surrounding the left side of Pluto’s heart-shaped feature – informally named Sputnik Planum – shows that the vast expanse of the icy surface is on average 2 miles (3 kilometers) lower than the surrounding terrain. Angular blocks of water ice are “floating” in the bright deposits of softer, denser solid nitrogen. Credits: NASA/JHUAPL/SwRI

“Sputnik Planum – shows that the vast expanse of the icy surface is on average 2 miles (3 kilometers) lower than the surrounding terrain. Angular blocks of water ice along the western edge of Sputnik Planum can be seen “floating” in the bright deposits of softer, denser solid nitrogen,” according to the team.

Even more stunning images and groundbreaking data will continue streaming back from New Horizons until early fall, across over 3 billion miles of interplanetary space.

Thus the global map of Pluto will be periodically updated.

Its taking over a year to receive the full complement of some 50 gigabits of data due to the limited bandwidth available from the transmitter on the piano-shaped probe as it hurtled past Pluto, its largest moon Charon and four smaller moons.

Pluto is the last planet in our solar system to be visited in the initial reconnaissance of planets by spacecraft from Earth since the dawn of the Space Age.

This new global mosaic view of Pluto was created from the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft and released on Sept. 11, 2015. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). This new mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com
This new global mosaic view of Pluto was created from the latest high-resolution images to be downlinked from NASA’s New Horizons spacecraft and released on Sept. 11, 2015. The images were taken as New Horizons flew past Pluto on July 14, 2015, from a distance of 50,000 miles (80,000 kilometers). This new mosaic was stitched from over two dozen raw images captured by the LORRI imager and colorized. Annotated with informal place names. Credits: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Marco Di Lorenzo/Ken Kremer/kenkremer.com

New Horizons remains on target to fly by a second Kuiper Belt Object (KBO) on Jan. 1, 2019 – tentatively named PT1, for Potential Target 1. It is much smaller than Pluto and was recently selected based on images taken by NASA’s Hubble Space Telescope.

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

Ken Kremer

2015: NASA’s Year of the Dwarf Planet

Together, the space probes Dawn and New Horizons have been in flight for a collective 17 years. One remained close to home and the other departed to parts of the Solar System of which little is known. They now share a common destination in the same year: dwarf planets.

At the time of these NASA probes’ departures, Ceres had just lost its designation as the largest asteroid in our Solar System. Pluto was the ninth planet. Both probes now stand to deliver measures of new data and insight that could spearhead yet another revision of the definition of planet.

A comparison of the trajectories of New Horizon (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes)
A comparison of the trajectories of New Horizons (left) and the Dawn missions (right). (Credit: NASA/JPL, SWRI, Composite- T.Reyes)

Certainly, NASA’s Year of the Dwarf Planet is an unofficial designation and NASA representatives would be quick to emphasize another dozen or more missions that are of importance during the year 2015. However, these two missions could determine the fate of billions or more small bodies just within our galaxy, the Milky Way.

If Ceres and Pluto are studied up close – mission success is never a sure thing – then what is observed could lead to a new, more certain and accepted definition of planet, dwarf planet, and possibly other new definitions.

The New Horizons mission became the first mission of NASA’s New Frontiers program, beginning development in 2001. The probe was launched on January 19, 2006, atop an Atlas V 551 (5 solid rocket boosters plus a third stage). Utilizing more compact and lightweight electronics than its predecessors to the outer planets – Pioneer 10 & 11, and Voyager 1 & 2 – the combination of reduced weight, a powerful launch vehicle, plus a gravity assist from Jupiter has lead to a nine year journey. On December 6, 2014, New Horizons was taken out of hibernation for the last time and now remains powered on until the Pluto encounter.

This "movie" of Pluto and its largest moon, Charon b yNASA's New Horizons spacecraft taken in July 2014 clearly shows that the barycenter -center of mass of the two bodies - resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto's surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
This “movie” of Pluto and its largest moon, Charon, by NASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter – the center of mass of the two bodies – resides outside (between) both bodies. The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera – the Long Range Reconnaissance Imager (LORRI) – at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

The arrival date of New Horizon is July 14, 2015. A telescope called the Long Range Reconnaissance Imager (LORRI) has permitted the commencement of observations while still over 240 million kilometers (150 million miles) from Pluto. The first stellar-like images were taken while still in the Asteroid belt in 2006.

Pluto was once the ninth planet of the Solar System. From its discovery in 1930 by Clyde Tombaugh until 2006, it maintained this status. In that latter year, the International Astronomical Union undertook a debate and then a membership vote that redefined what a planet is. The change occurred 8 months after New Horizons’ launch. There were some upset mission scientists, foremost of which was the principal investigator, Dr. Alan Stern, from the Southwest Research Institute in San Antonio, Texas. In a sense, the rug had been pulled from under them.

A gentleman’s battle ensued between opposing protagonists Dr. Stern and Dr. Michael Brown from Caltech. In 2001, Dr. Brown’s research team began to discover Kuiper belt objects (Trans-Neptunian objects) that rivaled the size of Pluto. Pluto suddenly appeared to be one of many small bodies that could likely number in the trillions within just one galaxy – ours. According to Dr. Brown, there could be as many as 200 objects in our Solar System similar to Pluto that, under the old definition, could be defined as planets. Dr. Brown’s work was the straw that broke the camel’s back – that is, it led to the redefinition of planet, and the native of Huntsville, Alabama, went on to write a popular book, How I Killed Pluto and Why It Had It Coming.

Dr. Stern’s story involving Pluto and planetary research is a longer and more circuitous one. Stern was the Executive Director of the Southwest Research Institute’s Space Science and Engineering Division and then accepted the position of Associate Administrator of NASA’s Science Mission Directorate in 2007. Clearly, after a nine year journey, Stern is now fully committed to New Horizons’ close encounter. More descriptions of the two protagonists of the Pluto debate will be included in a follow on story.

Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL)
Artist’s concept depicting the Dawn spacecraft thrusting with its ion propulsion system as it travels from Vesta (lower right) to Ceres (upper left). The galaxies in the background are part of the Virgo supercluster. Dawn, Vesta, and Ceres are currently in the constellation Virgo from the perspective of viewers on Earth. (Image credit: NASA/JPL)

The JPL and Orbital Science Corporation developed Dawn space probe began its journey to the main asteroid belt on September 27, 2007. It has used gravity assists and flew by the planet Mars. Dawn spent 14 months surveying Vesta, the 4th largest asteroid of the main belt (assuming Ceres is still considered the largest). While New Horizons has traveled over 30 Astronomical Units (A.U.) – 30 times the distance from the Earth to the Sun – Dawn has remained closer and required reaching a little over 2 A.U. to reach Vesta and now 3 A.U. to reach Ceres.

The Dawn mission had the clear objective of rendezvous and achieving orbit with two asteroids in the main belt between Mars and Jupiter. Dawn was also sent packing the next generation of Ion Propulsion. It has proven its effectiveness very well, having used ion propulsion for the first time to achieve an orbit. Pretty simple, right? Not so fast.

As Dawn was passing critical design reviews during development, the redefinition of planet lofted its second objective – the asteroid 1 Ceres – to a new status. While Pluto was demoted, Ceres was promoted from its scrappy status of biggest of the asteroids – the debris, the leftovers of our solar system’s development – to dwarf planet. Even 4 Vesta is now designated a proto-planet.

Artist rendition of Dawn spacecraft orbiting Vesta(Credit: NASA/JPL-Caltech)
Artist rendition of Dawn spacecraft orbiting Vesta. (Credit: NASA/JPL-Caltech)

So now the stage is set. Dawn will arrive first at a dwarf planet – Ceres – in April. With a small, low gravity body and ion propulsion, the arrival is slow and cautious. If the two missions fair well and achieve their goals, 2015 is likely to become a pivotal year in the debate over the classification of non-stellar objects throughout the universe.

Just days ago, at the American Geophysical Union Conference in San Francisco, Dr. Stern and team described the status and more details of the goals of New Horizons. Since arriving, more moons of Pluto have been discovered. There is the potential that faint rings exist and Pluto may even harbor an interior ocean due to the tidal forces from its largest moon, Charon. And Dawn mission scientists have seen the prospects for Ceres’ change. Not just the status, the latest Hubble images of Ceres is showing bright spots which could be water ice deposits and could also harbor an internal ocean.

The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth's Moon, here called "Luna." None of the distances between objects are to scale. (Credit: NASA)
The Solar System is becoming a more crowded place. This picture shows the sizes of dwarf planets Pluto, Ceres, Eris, and Makemake as compared to Earth and Earth’s Moon, here called “Luna.” None of the distances between objects are to scale. (Credit: NASA)

So other NASA missions notwithstanding, this is the year of the dwarf planet. NASA will provide Humanity with its first close encounters with the most numerous of small round – by their self-gravity – bodies in the Universe. They are now called dwarf planets but ask Dr. Stern and company, the public, and many other planetary scientists and you will discover that the jury is still out.

References:

JHU/APL New Horizons Mission Home Page

NASA Dawn Mission Home Page

Related Universe Today articles:

NASA’s New Horizons

NASA’s Dawn Mission

Hubble Discovers Water Plumes Erupting from Europa

It’s been known since 2005 that Saturn’s 300-mile-wide moon Enceladus has geysers spewing ice and dust out into orbit from deep troughs that rake across its south pole. Now, thanks to the Hubble Space Telescope (after 23 years still going strong) we know of another moon with similar jets: Europa, the ever-enigmatic ice-shelled moon of Jupiter. This makes two places in our Solar System where subsurface oceans could be getting sprayed directly into space — and within easy reach of any passing spacecraft.

(Psst, NASA… hint hint.)

The findings were announced today during the meeting of the American Geophysical Union in San Francisco.

“The discovery that water vapor is ejected near the south pole strengthens Europa’s position as the top candidate for potential habitability,” said lead author Lorenz Roth of the Southwest Research Institute (SwRI) in San Antonio, Texas. “However, we do not know yet if these plumes are connected to subsurface liquid water or not.”

The 125-mile (200-km) -high plumes were discovered with Hubble observations made in December 2012. Hubble’s Space Telescope Imaging Spectrograph (STIS) detected faint ultraviolet light from an aurora at the Europa’s south pole. Europa’s aurora is created as it plows through Jupiter’s intense magnetic field, which causes particles to reach such high speeds that they can split the water molecules in the plume when they hit them. The resulting oxygen and hydrogen ions revealed themselves to Hubble with their specific colors.

Unlike the jets on Enceladus, which contain ice and dust particles, only water has so far been identified in Europa’s plumes. (Source)

Rendering showing the location and size of water vapor plumes coming from Europa's south pole.
Rendering showing the location and size of water vapor plumes coming from Europa’s south pole.

The team suspects that the source of the water is Europa’s long-hypothesized subsurface ocean, which could contain even more water than is found across the entire surface of our planet.

Read more: Europa’s Hidden Great Lakes May Harbor Life

“If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice,” Roth said. “And that is tremendously exciting.”

One other possible source of the water vapor could be surface ice, heated through friction.

Cassini image of ice geysers on Enceladus (NASA/JPL/SSI)
Cassini image of ice geysers on Enceladus (NASA/JPL/SSI)

In addition the Hubble team found that the intensity of Europa’s plumes, like those of Enceladus, varies with the moon’s orbital position around Jupiter. Active jets have been seen only when Europa is farthest from Jupiter. But the researchers could not detect any sign of venting when Europa is closer.

One explanation for the variability is Europa undergoes more tidal flexing as gravitational forces push and pull on the moon, opening vents at larger distances from Jupiter. The vents get narrowed or even seal off entirely when the moon is closest to Jupiter.

Still, the observation of these plumes — as well as their varying intensity — only serves to further support the existence of Europa’s ocean.

“The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean,” said Kurt Retherford, also of SwRI.

(Science buzzkill alert: although exciting, further observations will be needed to confirm these findings. “This is a 4 sigma detection, so a small uncertainly that the signal is just noise in the instruments,” noted Roth.)

“If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system.”

– John Grunsfeld, NASA’s Associate Administrator for Science

Read more: Hydrogen Peroxide Could Feed Life on Europa

So. Who’s up for a mission to Europa now? (And unfortunately in this case, Juno doesn’t count.)

“Juno is a spinning spacecraft that will fly close to Jupiter, and won’t be studying Europa,” Kurt Retherford told Universe Today. “The team is looking hard how we can optimize, maybe looking for gases coming off Europa and look at how the plasma interacts with environment, so we really need a dedicated Europa mission.”

We couldn’t agree more.

The findings were published in the Dec. 12 online issue of Science Express.

Sources: Hubble news releases (US and ESA)

Image credits:
Graphic Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany)
Science Credit: NASA, ESA, L. Roth (Southwest Research Institute and University of Cologne, Germany), J. Saur (University of Cologne, Germany), K. Retherford (Southwest Research Institute), D. Strobel and P. Feldman (Johns Hopkins University), M. McGrath (Marshall Space Flight Center), and F. Nimmo (University of California, Santa Cruz)

Plastic Protection Against Cosmic Rays?

It could work, say researchers from the University of New Hampshire and the Southwest Research Institute.

One of the inherent dangers of space travel and long-term exploration missions beyond Earth is the constant barrage of radiation, both from our own Sun and in the form of high-energy particles originating from outside the Solar System called cosmic rays. Extended exposure can result in cellular damage and increased risks of cancer at the very least, and in large doses could even result in death. If we want human astronauts to set up permanent outposts on the Moon, explore the dunes and canyons of Mars, or mine asteroids for their valuable resources, we will first need to develop adequate (and reasonably economical) protection from dangerous space radiation… or else such endeavors will be nothing more than glorified suicide missions.

While layers of rock, soil, or water could protect against cosmic rays, we haven’t yet developed the technology to hollow out asteroids for spaceships or build stone spacesuits (and sending large amounts of such heavy materials into space isn’t yet cost-effective.)  Luckily, there may be a much easier way to protect astronauts from cosmic rays — using lightweight plastics.

While aluminum has always been the primary material in spacecraft construction, it provides relatively little protection against high-energy cosmic rays and can add so much mass to spacecraft that they become cost-prohibitive to launch.

Using observations made by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) orbiting the Moon aboard LRO, researchers from UNH and SwRI have found that plastics, adequately designed, can provide better protection than aluminum or other heavier materials.

“This is the first study using observations from space to confirm what has been thought for some time—that plastics and other lightweight materials are pound-for-pound more effective for shielding against cosmic radiation than aluminum,” said Cary Zeitlin of the SwRI Earth, Oceans, and Space Department at UNH. “Shielding can’t entirely solve the radiation exposure problem in deep space, but there are clear differences in effectiveness of different materials.”

Zeitlin is lead author of a paper published online in the American Geophysical Union journal Space Weather.

A block of tissue-equivalent plastic (Credit: UNH)
A block of tissue-equivalent plastic (TEP) Credit: UNH

The plastic-aluminum comparison was made in earlier ground-based tests using beams of heavy particles to simulate cosmic rays. “The shielding effectiveness of the plastic in space is very much in line with what we discovered from the beam experiments, so we’ve gained a lot of confidence in the conclusions we drew from that work,” says Zeitlin. “Anything with high hydrogen content, including water, would work well.”

The space-based results were a product of CRaTER’s ability to accurately gauge the radiation dose of cosmic rays after passing through a material known as “tissue-equivalent plastic,” which simulates human muscle tissue.

(It may not look like human tissue, but it collects energy from cosmic particles in much the same way.)

Prior to CRaTER and recent measurements by the Radiation Assessment Detector (RAD) on the Mars rover Curiosity, the effects of thick shielding on cosmic rays had only been simulated in computer models and in particle accelerators, with little observational data from deep space.

The CRaTER observations have validated the models and the ground-based measurements, meaning that lightweight shielding materials could safely be used for long missions — provided their structural properties can be made adequate to withstand the rigors of spaceflight.

Sources: EurekAlert and [email protected]