The Managed, Reconfigurable, In-space Nodal Assembly (MARINA), developed by MIT graduate students, is designed as a habitable commercially owned module for use in low Earth orbit. Credit: MIT/MARINA team
Looking to the future of space exploration, there really is no question that it will involve a growing human presence in Low Earth Orbit (LEO). This will include not only successors to the International Space Station, but most likely commercial habitats and facilities. These will not only allow for ventures like space tourism, but will also facilitate missions that take us back to the Moon, to Mars, and even beyond.
With this purpose in mind, an interdisciplinary team of MIT graduate students designed a space habitat known as the Managed, Reconfigurable, In-space Nodal Assembly (MARINA). This module would serve as an privately-owned space station that would be occupied by two anchor-tenants for a period of ten years; a luxury hotel that would provide orbital accommodations, and NASA.
For their invention, the team won first prize in the graduate division of the Revolutionary Aerospace Systems Concepts-Academic Linkage Design Competition Forum (RASC-AL), a yearlong graduate-level competition hosted by NASA. This challenge involved designing a commercial module for use in low Earth orbit that could also serve as a Mars transit vehicle in the future.
In the future, LEO will become home to commercial modules (like the Bigelow Aerospace B330 expandable module, shown here), will become a reality. Credit: Bigelow Aerospace
Since 2002, RASC-AL competitions have sought to engage university students and advisors for the purpose of coming up with ideas that could enhancing future NASA missions. For this year’s competition, NASA asked teams to develop human spaceflight concepts that focused on operations in cislunar space – i.e. in, around, and beyond the Moon – that could also facilitate their proposed “Journey to Mars” by the 2030s.
Specifically, they were tasked with finding ways to leverage innovations and new technologies to improve humanity’s ability to work more effectively in microgravity. With this in mind, the themes for this year’s competition ranged from from the design of more efficient subsystems to the development of architectures that support NASA’s goal of extending humanity’s reach into space.
These included new designs for a Lightweight Exercise Suite, Airlock Design, concepts for a Commercially Enabled LEO/Mars Habitable Module, and concepts for a new Logistics Delivery System. As Pat Troutman, the Human Exploration Strategic Analysis lead at NASA’s Langley Research Center, said in a NASA press statement:
“We are carefully examining what it will take to establish a presence beyond low-Earth orbit, where astronauts will build and begin testing the systems needed for challenging missions to distant destinations, including Mars. The 2017 RASC-AL university teams have developed exciting concepts with supporting engineering analysis that may influence how future deep space infrastructure will look and operate.”
Members of the MIT team (from left to right): Caitlin Mueller (faculty advisor), Matthew Moraguez, George Lordos, and Valentina Sumini. Credit: MIT/MARINA team
Led by Matthew Moraguez, a graduate student at MIT’s Department of Aeronautics and Astronautics (AeroAstro) and a member of the Strategic Engineering Research Group (SERG), the MIT team focused on the theme of creating a Commercially Enabled LEO Habitat Module. Their concept, which incorporates lessons that have been learned from the ISS, was designed with the needs of both the private and public space sectors in mind.
“Just like a yacht marina, MARINA can provide all essential services, including safe harbor, reliable power, clean water and air, and efficient logistics and maintenance. This will facilitate design simplicity and savings in construction and operating costs of customer-owned modules. It will also incent customers to lease space inside and outside MARINA’s node modules and make MARINA a self-funded entity that is attractive to investors.”
To meet their goals for the competition , the team came up with a modular design for MARINA that featured several key innovations. These included extensions to the International Docking System Standard (IDSS) interface (used aboard the ISS), modular architecture, and a distribution of subsystem functions throughout these modules. As Moraguez explained, their design will allow for some wide-ranging opportunities.
“Modularized service racks connect any point on MARINA to any other point via the extended IDSS interface,” he said. “This enables companies of all sizes to provide products and services in space to other companies, based on terms determined by the open market. Together these decisions provide scalability, reliability, and efficient technology development benefits to MARINA and NASA.”
Another important benefit comes in the form of cost-savings. According to NASA estimates, the recurring cost of MARINA will be about $360 million per year, which represents a significant reduction over the current costs of maintaining and operating the ISS. In total, it would offer NASA a savings of about $3 billion per year, which is approximately 16% of the agency’s annual budget.
But what is perhaps most interesting about the MARINA concept is the fact that it could serve as the world’s first space hotel. According to Valentina Suminia, a postdoc at MIT who contributed to the architectural concept, the space hotel will be “a luxury Earth-facing eight-room space hotel complete with bar, restaurant, and gym, will make orbital space holidays a reality.”
Other commercial features include serviced berths that would be rented out to accommodate customer-owned modules. This goes for the station’s interior modularized rack space as well, where smaller companies that provide contract services to on-board occupants would be able to rent out space. Would it be too much to ask that it also has robot butlers?
The RASCAL competition began in August of 2016 in Cocoa Beach, Florida, and concluded on June 2nd, 2017. The top overall honors were awarded to the teams from Virginia Tech and the University of Maryland for their space habitat concepts, known as Project Theseus and Ultima Thule, respectively.
The Milky Way is an extremely big place. Measured from end to end, our galaxy in an estimated 100,000 to 180,000 light years (31,000 – 55,000 parsecs) in diameter. And it is extremely well-populated, with an estimated 100 to 400 million stars contained within. And according to recent estimates, it is believed that there are as many as 100 billion planets in the Milky Way. And our galaxy is merely one of trillions within the Universe.
So if we were to break it down, just how much matter would we find out there? Estimating how much there is overall would involve some serious math and incredible figures. But what about a single light year? As the most commonly-used unit for measuring the distances between stars and galaxies, determining how much stuff can be found within a single light year (on average) is a good way to get an idea of how stuff is out there.
Light Year:
Even though the name is a little confusing, you probably already know that a light year is the distance that light travels in the space of a year. Given that the speed of light has been measured to 299,792, 458 m/s (1080 million km/h; 671 million mph), the distance light travels in a single year is quite immense. All told, a single light year works out to 9,460,730,472,580.8 kilometers (5,878,625,373,183.6 mi).
Diagram showing the distance light travels between the Sun and the Earth. Credit: Wikipedia Commons/Brews ohare
So to determine how much stuff is in a light year, we need to take that distance and turn it into a cube, with each side measuring one light year in length. Imagine that giant volume of space (a little challenging for some of us to get our heads around) and imagine just how much “stuff” would be in there. And not just “stuff”, in the sense of dust, gas, stars or planets, either. How much nothing is in there, as in, the empty vacuum of space?
There is an answer, but it all depends on where you put your giant cube. Measure it at the core of the galaxy, and there are stars buzzing around all over the place. Perhaps in the heart of a globular cluster? In a star forming nebula? Or maybe out in the suburbs of the Milky Way? There’s also great voids that exist between galaxies, where there’s almost nothing.
Density of the Milky Way:
There’s no getting around the math in this one. First, let’s figure out an average density for the Milky Way and then go from there. Its about 100,000 to 180,000 light-years across and 1000 light-years thick. According to my buddy and famed astronomer Phil Plait (of Bad Astronomy), the total volume of the Milky Way is about 8 trillion cubic light-years.
And the total mass of the Milky Way is 6 x 1042 kilograms (that’s 6,000 trillion trillion trillion metric tons or 6,610 trillion trillion trillion US tons). Divide those together and you get 8 x 1029 kilograms (800 trillion trillion metric tons or 881.85 trillion trillion US tons) per light year. That’s an 8 followed by 29 zeros. This sounds like a lot, but its actually the equivalent of 0.4 Solar Masses – 40% of the mass of our Sun.
Millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture. Credit: ESO
In other words, on average, across the Milky Way, there’s about 40% the mass of the Sun in every cubic light year. But in an average cubic meter, there’s only about 950 attograms, which is almost one femtogram (a quadrillionth of a gram of matter), which is pretty close to nothing. Compare this to air, which has more than a kilogram of mass per cubic meter.
To be fair, in the densest regions of the Milky Way – like inside globular clusters – you can get densities of stars with 100, or even 1000 times greater than our region of the galaxy. Stars can get as close together as the radius of the Solar System. But out in the vast interstellar gulfs between stars, the density drops significantly. There are only a few hundred individual atoms per cubic meter in interstellar space.
And in the intergalactic voids; the gulfs between galaxies, there are just a handful of atoms per meter. Like it or not, much of the Universe is pretty close to being empty space, with just trace amounts of dust or gas particles to be found between all the stars, galaxies, clusters and super clusters.
So how much stuff is there in a light year? It all depends on where you look, but if you spread all the matter around by shaking the Universe up like a snow globe, the answer is very close to nothing.
Mercury and Earth, size comparison. Credit: NASA / APL (from MESSENGER)
Mercury was appropriately named after the Roman messenger of the Gods. This is owed to the fact that its apparent motion in the night sky was faster than that of any of the other planets. As astronomers learned more about this “messenger planet”, they came to understand that its motion was due to its close orbit to the Sun, which causes it to complete a single orbit every 88 days.
Mercury’s proximity to the Sun is merely one of its defining characteristics. Compared to the other planets of the Solar System, it experiences severe temperature variations, going from very hot to very cold. It’s also very rocky, and has no atmosphere to speak of. But to truly get a sense of how Mercury stacks up compared to the other planets of the Solar System, we need to a look at how Mercury compares to Earth.
Size, Mass and Orbit:
The diameter of Mercury is 4,879 km, which is approximately 38% the diameter of Earth. In other words, if you put three Mercurys side by side, they would be a little larger than the Earth from end to end. While this makes Mercury smaller than the largest natural satellites in our system – such as Ganymede and Titan – it is more massive and far more dense than they are.
Mercury, as imaged by the MESSENGER spacecraft, revealing parts of the never seen by human eyes. Image Credit: NASA/JHUAPL/Carnegie Institution of Washington
In fact, Mercury’s mass is approximately 3.3 x 1023 kg (5.5% the mass of Earth) which means that its density – at 5.427 g/cm3 – is the second highest of any planet in the Solar System, only slightly less than Earth’s (5.515 g/cm3). This also means that Mercury’s surface gravity is 3.7 m/s2, which is the equivalent of 38% of Earth’s gravity (0.38 g). This means that if you weighed 100 kg (220 lbs) on Earth, you would weigh 38 kg (84 lbs) on Mercury.
Meanwhile, the surface area of Mercury is 75 million square kilometers, which is approximately 10% the surface area of Earth. If you could unwrap Mercury, it would be almost twice the area of Asia (44 million square km). And the volume of Mercury is 6.1 x 1010 km3, which works out to 5.4% the volume of Earth. In other words, you could fit Mercury inside Earth 18 times over and still have a bit of room to spare.
In terms of orbit, Mercury and Earth probably could not be more different. For one, Mercury has the most eccentric orbit of any planet in the Solar System (0.205), compared to Earth’s 0.0167. Because of this, its distance from the Sun varies between 46 million km (29 million mi) at its closest (perihelion) to 70 million km (43 million mi) at its farthest (aphelion).
This puts Mercury much closer to the Sun than Earth, which orbits at an average distance of 149,598,023 km (92,955,902 mi), or 1 AU. This distance ranges from 147,095,000 km (91,401,000 mi) to 152,100,000 km (94,500,000 mi) – 0.98 to 1.017 AU. And with an average orbital velocity of 47.362 km/s (29.429 mi/s), it takes Mercury a total 87.969 Earth days to complete a single orbit – compared to Earth’s 365.25 days.
The Orbit of Mercury during the year 2006. Credit: Wikipedia Commons/Eurocommuter
However, since Mercury also takes 58.646 days to complete a single rotation, it takes 176 Earth days for the Sun to return to the same place in the sky (aka. a solar day). So on Mercury, a single day is twice as long as a single year. Meanwhile on Earth, a single solar day is 24 hours long, owing to its rapid rotation of 1674.4 km/h. Mercury also has the lowest axial tilt of any planet in the Solar System – approximately 0.027°, compared to Earth’s 23.439°.
Structure and Composition:
Much like Earth, Mercury is a terrestrial planet, which means it is composed of silicate minerals and metals that are differentiated between a solid metal core and a silicate crust and mantle. For Mercury, the breakdown of these elements is higher than Earth. Whereas Earth is primarily composed of silicate minerals, Mercury is composed of 70% metallic and 30% of silicate materials.
Also like Earth, Mercury’s interior is believed to be composed of a molten iron that is surrounded by a mantle of silicate material. Mercury’s core, mantle and crust measure 1,800 km, 600 km, and 100-300 km thick, respectively; while Earth’s core, mantle and crust measure 3478 km, 2800 km, and up to 100 km thick, respectively.
What’s more, geologists estimate that Mercury’s core occupies about 42% of its volume (compared to Earth’s 17%) and the core has a higher iron content than that of any other major planet in the Solar System. Several theories have been proposed to explain this, the most widely accepted being that Mercury was once a larger planet that was struck by a planetesimal that stripped away much of the original crust and mantle.
Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL
Surface Features:
In terms of its surface, Mercury is much more like the Moon than Earth. It has a dry landscape pockmarked by asteroid impact craters and ancient lava flows. Combined with extensive plains, these indicate that the planet has been geologically inactive for billions of years.
Names for these features come from a variety of sources. Craters are named for artists, musicians, painters, and authors; ridges are named for scientists; depressions are named after works of architecture; mountains are named for the word “hot” in different languages; planes are named for Mercury in various languages; escarpments are named for ships of scientific expeditions, and valleys are named after radio telescope facilities.
During and following its formation 4.6 billion years ago, Mercury was heavily bombarded by comets and asteroids, and perhaps again during the Late Heavy Bombardment period. Due to its lack of an atmosphere and precipitation, these craters remain intact billions of years later. Craters on Mercury range in diameter from small bowl-shaped cavities to multi-ringed impact basins hundreds of kilometers across.
The largest known crater is Caloris Basin, which measures 1,550 km (963 mi) in diameter. The impact that created it was so powerful that it caused lava eruptions on the other side of the planet and left a concentric ring over 2 km (1.24 mi) tall surrounding the impact crater. Overall, about 15 impact basins have been identified on those parts of Mercury that have been surveyed.
Enhanced-color image of Munch, Sander and Poe craters amid volcanic plains (orange) near Caloris Basin. Credit: NASA/JHUAPL/Carnegie Institution of Washington
Earth’s surface, meanwhile, is significantly different. For starters, 70% of the surface is covered in oceans while the areas where the Earth’s crust rises above sea level forms the continents. Both above and below sea level, there are mountainous features, volcanoes, scarps (trenches), canyons, plateaus, and abyssal plains. The remaining portions of the surface are covered by mountains, deserts, plains, plateaus, and other landforms.
Mercury’s surface shows many signs of being geologically active in the past, mainly in the form of narrow ridges that extend up to hundreds of kilometers in length. It is believed that these were formed as Mercury’s core and mantle cooled and contracted at a time when the crust had already solidified. However, geological activity ceased billions of years ago and its crust has been solid ever since.
Meanwhile, Earth is still geologically active, owning to convection of the mantle. The lithosphere (the crust and upper layer of the mantle) is broken into pieces called tectonic plates. These plates move in relation to one another and interactions between them is what causes earthquakes, volcanic activity (such as the “Pacific Ring of Fire“), mountain-building, and oceanic trench formation.
Atmosphere and Temperature:
When it comes to their atmospheres, Earth and Mercury could not be more different. Earth has a dense atmosphere composed of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. Earth’s atmosphere is also primarily composed of nitrogen (78%) and oxygen (21%) with trace concentrations of water vapor, carbon dioxide, and other gaseous molecules.
The Fast Imaging Plasma Spectrometer on board MESSENGER has found that the solar wind is able to bear down on Mercury enough to blast particles from its surface into its wispy atmosphere. Credit: Shannon Kohlitz, Media Academica, LLC
Because of this, the average surface temperature on Earth is approximately 14°C, with plenty of variation due to geographical region, elevation, and time of year. The hottest temperature ever recorded on Earth was 70.7°C (159°F) in the Lut Desert of Iran, while the coldest temperature was -89.2°C (-129°F) at the Soviet Vostok Station on the Antarctic Plateau.
Mercury, meanwhile, has a tenuous and variable exosphere that is made up of hydrogen, helium, oxygen, sodium, calcium, potassium and water vapor, with a combined pressure level of about 10-14 bar (one-quadrillionth of Earth’s atmospheric pressure). It is believed this exosphere was formed from particles captured from the Sun, volcanic outgassing and debris kicked into orbit by micrometeorite impacts.
Because it lacks a viable atmosphere, Mercury has no way to retain the heat from the Sun. As a result of this and its high eccentricity, the planet experiences far more extreme variations in temperature than Earth does. Whereas the side that faces the Sun can reach temperatures of up to 700 K (427° C), the side that is in darkness can reach temperatures as low as 100 K (-173° C).
Despite these highs in temperature, the existence of water ice and even organic molecules has been confirmed on Mercury’s surface. The floors of deep craters at the poles are never exposed to direct sunlight, and temperatures there remain below the planetary average. In this respect, Mercury and Earth have something else in common, which is the presence of water ice in its polar regions.
Mercury’s Magnetic Field. Credit: NASA
Magnetic Fields:
Much like Earth, Mercury has a significant, and apparently global, magnetic field, one which is about 1.1% the strength of Earth’s. It is likely that this magnetic field is generated by a dynamo effect, in a manner similar to the magnetic field of Earth. This dynamo effect would result from the circulation of the planet’s iron-rich liquid core.
Mercury’s magnetic field is strong enough to deflect the solar wind around the planet, thus creating a magnetosphere. The planet’s magnetosphere, though small enough to fit within Earth, is strong enough to trap solar wind plasma, which contributes to the space weathering of the planet’s surface.
All told, Mercury and Earth are in stark contrast. While both are terrestrial in nature, Mercury is significantly smaller and less massive than Earth, though it has a similar density. Mercury’s composition is also much more metallic than that of Earth, and its 3:2 orbital resonance results in a single day being twice as long as a year.
But perhaps most stark of all are the extremes in temperature variations that Mercury goes through compared to Earth. Naturally, this is due to the fact that Mercury orbits much closer to the Sun than the Earth does and has no atmosphere to speak of. And its long days and long nights also mean that one side is constantly being baked by the Sun, or in freezing darkness.
Diagram showing the distance light travels between the Sun and the Earth. Credit: Wikipedia Commons/Brews ohare
The Universe is an extremely big place. As astronomers looked farther into space over the centuries, and deeper into the past, they came to understand just how small and insignificant our planet and our species seem by comparison. At the same time, ongoing investigations into electromagnetism and distant stars led scientists to deduce what the the speed of light is – and that it is the fastest speed obtainable.
As such, astronomers have taken to using the the distance light travels within a single year (aka. a light year) to measure distances on the interstellar and intergalactic scale. But how far does light travel in a year? Basically, it moves at a speed of 299,792,458 meters per second (1080 million km/hour; 671 million mph), which works out to about 9,460.5 trillion km (5,878.5 trillion miles) per year.
The Speed of Light:
Calculating the speed of light has been a preoccupation for scientists for many centuries. And prior to the 17th century, there was disagreement over whether the speed of light was finite, or if it moved from one spot to the next instantaneously. In 1676, Danish astronomer Ole Romer settled the argument when his observations of the apparent motion of Jupiter’s moon Io revealed that the speed of light was finite.
Light moves at different wavelengths, represented here by the different colors seen in a prism. Credit: NASA/ESA
From his observations, famed Dutch astronomer Christiaan Huygens calculated the speed of light at 220,000 km/s (136,701 mi/s). Over the course of the nest two centuries, the speed of light was refined further and further, producing estimates that ranged from about 299,000 to 315,000 km/s (185,790 to 195,732 mi/s).
This was followed by James Clerk Maxwell, who proposed in 1865 that light was an electromagnetic wave. In his theory of electromagnetism, the speed of light was represented as c. And then in 1905, Albert Einstein proposed his theory of Special Relativity, which postulated that the speed of light (c) was constant, regardless of the inertial reference frame of the observer or the motion of the light source.
By 1975, after centuries of refined measurements, the speed of light in a vacuum was calculated at 299,792,458 meters per second. Ongoing research also revealed that light travels at different wavelengths and is made up of subatomic particles known as photons, which have no mass and behave as both particles and waves.
Light-Year:
As already noted, the speed of light (expressed in meters per second) means that light travels a distance of 9,460,528,000,000 km (or 5,878,499,817,000 miles) in a single year. This distance is known as a “light year”, and is used to measure objects in the Universe that are at a considerable distances from us.
Examples of objects in our Universe, and the scale of their distances, based on the light year as a standard measure. Credit: Bob King.
For example, the nearest star to Earth (Proxima Centauri) is roughly 4.22 light-years distant. The center of the Milky Way Galaxy is 26,000 light-years away, while the nearest large galaxy (Andromeda) is 2.5 million light-years away. To date, the candidate for the farthest galaxy from Earth is MACS0647-JD, which is located approximately 13.3 billion light years away.
And the Cosmic Microwave Background, the relic radiation which is believed to be leftover from the Big Bang, is located some 13.8 billion light years away. The discovery of this radiation not only bolstered the Big Bang Theory, but also gave astronomers an accurate assessment of the age of the Universe. This brings up another important point about measuring cosmic distances in light years, which is the fact that space and time are intertwined.
You see, when we see the light coming from a distant object, we’re actually looking back in time. When we see the light from a star located 400 light-years away, we’re actually seeing light that was emitted from the star 400 years ago. Hence, we’re seeing the star as it looked 400 years ago, not as it appears today. As a result, looking at objects billions of light-years from Earth is to see billions of light-years back in time.
Yes, light travels at an extremely fast speed. But given the sheer size and scale of the Universe, it can still take billions of years from certain points in the Universe to reach us here on Earth. Hence why knowing how long it takes for light to travel a single year is so useful to scientists. Not only does it allow us to comprehend the scale of the Universe, it also allows us to chart the process of cosmic evolution.
Never used SpaceX Falcon 9 is seen rising to launch position and now stands erect and poised for liftoff Intelsat 35e on July 3, 2017 at Launch Complex 39A at NASA's Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
Never used SpaceX Falcon 9 is seen rising to launch position and now stands erect and poised for Intelsat 35e liftoff on July 5, 2017 at Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – Spectacular 4th of July fireworks are coming tonight, July 3,[reset to July5] to the Florida Space Coast courtesy of SpaceX and Intelsat with the planned near dusk launch of the commercial Epic 35e next-generation high throughput satellite to geostationary orbit for copious customers in the Americas, Europe and Africa. UPDATE: After a 2nd abort launch is now NET July 5.
JULY 5 UPDATE: GO for launch attempt tonight at 7:37 PM. Weather looks good at this time.
“SpaceX, confirms that we are ‘Go’ for a launch tonight, 5 July, at approximately 23:37:00 UTC (7:37pm EDT), GO INTELSAT 35E!!” Intelsat announced.
Originally slated for Sunday evening, July 2, the launch was automatically aborted by the computer control systems literally in the final moments before the scheduled liftoff due to a guidance issue, and under picture perfect weather conditions – which would have resulted in 3 launches in 9 days.
Following the 24 hour scrub turnaround, blastoff of the Intelsat 35e communications satellite for commercial broadband provider Intelsat is now slated for dinnertime early Monday evening, July 3 at 7:37 p.m. EDT, or 2337 UTC from SpaceX’s seaside Launch Complex 39A on NASA’s Kennedy Space Center in Florida.
Up close view of payload fairing encapsulating Intelsat 35e comsat launching atop expendable SpaceX Falcon 9 booster at Launch Complex 39A at NASA’s Kennedy Space Center in Florida. This booster is not equipped with grid fins or landing legs. Credit: Ken Kremer/kenkremer.com
The first stage will not be recovered for this launch because the massive 6800 kg Intelsat 35e comsat requires every drop of fuel to get to the desired orbit.
“There will be no return of the booster for this mission, “ Ken Lee, Intelsat’s senior vice president of space systems, told Universe Today in a prelaunch interview on Sunday.
“We [Intelsat] need all the fuel to get to orbit.”
By using all available fuel on board the Falcon 9, Intelsat 35e will be delivered to a higher orbit.
“This will enable us to use less fuel for orbit raising maneuvers and make more available for station keeping maneuvers,” Lee told me.
“We hope this will potentially extend the satellites lifetime by 1 or 2 years.”
“Intelsat 35e is the fourth in the series of our ‘Epic’ satellites. It will provide the most advanced digital services ever and a global footprint.”
You can watch the launch live on a SpaceX dedicated webcast starting about 15 minutes prior to the opening of the launch window at 7:37 p.m. EDT, or 2337 UTC
The never before used Falcon 9’s launch window extends for nearly an hour – 58 minutes – until 8:35 p.m. EDT, July 5, or 0035 UTC
Expendable SpaceX Falcon 9 is seen rising to launch position and is now erected to launch position and poised for liftoff with Intelsat 35e on July 5, 2017 at Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
“Our whole team had to activate quickly to get Intelsat 35e into this window and ready for launch. The good news is we partnered with SpaceX and Boeing, the satellite builder,” said Kurt Riegel Sr VP Intelsat Sales & Markenting, in an interview with Universe Today at the countdown clock at the KSC Press Site.
There was barely a week to turn around the Falcon 9 rocket and launch pad sinevc the blastoff of BulgariaSat-1.
“Boeing got everything accomplished on time and not give an inch on our test schedule or our quality which is so important to us.”
Monday’s [now Wednesday July] weather forecast is currently 70% GO for favorable conditions at launch time.
The weather odds have changed dramatically all week – trending more favorable.
The concern is for the Cumulus Cumulus Cloud Rule according to Air Force meteorologists with the 45th Space Wing at Patrick Air Force Base.
Monday’s abort took place 10 seconds before liftoff but was called at T-Zero by the SpaceX launch director. A problem was detected with the GNC system, which stands for guidance, navigation and control.
“We had a vehicle abort criteria violated at T-minus 10 seconds, a GNC criteria,” the launch director announced on the SpaceX webcast soon after the abort was called.
“We’re still looking into what that is at this time.
He then announced a scrub for the day.
“We’re not going to be able to get a recycle in today without going past the end of the window, so we’re officially scrubbed,” he stated on the webcast.
“Go ahead and put a 24-hour recycle into work.”
SpaceX Falcon 9 is poised for liftoff with Intelsat 35e – 4th next gen ‘Epic’ comsat on July 5, 2017 at Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
The brand new 29 story tall SpaceX Falcon 9 will deliver Intelsat 35e to a Geostationary Transfer Orbit (GTO).
The geostationary comsat will provide high performance services in the C- And Ku-bands to customers in North and South America, the Caribbean, as well as the continents of Europe and Africa.
Artists concept of Intelsat 35e in geostationary Earth orbit. Credit: Intelsat
The Ku band service includes a customized high power beam for direct-to-home television (DTH) and data communications services in the Caribbean as well as mobility services in Europe and Africa.
Hordes of spectators lined local area beaches and causeways north and south of the launch pad in anticipation of Sunday’s launch.
Many are expected to return given the promising weather forecast and July 4th holiday weekend.
The 229-foot-tall (70-meter) Falcon 9/Intelsat 353e rocket was raised erect Sunday morning, July 2 and is poised for liftoff and undergoing final prelaunch preparations.
The first and second stages will again be fueled with liquid oxygen and RP-1 propellants starting about one hour before liftoff.
Intelsat 35e marks the tenth SpaceX launch of 2017 – establishing a new single year launch record for SpaceX.
Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
The recent BulgariaSat-1 and Iridium-2 missions counted as the eighth and ninth SpaceX launches of 2017.
SpaceX conducts successful static hot fire test of Falcon 9 booster atop Launch Complex 39A at the Kennedy Space Center on 29 June 2017 as seen from Banana River lagoon, Titusville, FL. The Falcon 9 is slated to launch Intelsat 35e on July 3, 2017. Credit: Ken Kremer/Kenkremer.comSpaceX conducts successful static hot fire test of Falcon 9 booster atop Launch Complex 39A at the Kennedy Space Center on 29 June 2017 as seen from Banana River lagoon, Titusville, FL. The Falcon 9 is slated to launch Intelsat 35e on July 3, 2017. Credit: Ken Kremer/Kenkremer.com
Including those last two ocean platform landings, SpaceX has now successfully recovered 13 boosters; 5 by land and 8 by sea, over the past 18 months.
Watch for Ken’s onsite Intelsat 35e 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.
What a magnificent space sight to behold ! Cruise Ships and Recycled Rockets float side by side in Port Canaveral after recycled SpaceX Falcon 9 1st stage from BulgariaSat-1 launch from KSC on 23 June floats into port atop droneship on 29 June 2017. Credit: Ken Kremer/kenkremer.comSpaceX Falcon 9 Booster leaning atop OCISLY droneship upon which it landed after 23 June launch from KSC floats into Port Canaveral, FL, on 29 June 2017, hauled by tugboat as seen from Jetty Park Pier. Credit: Ken Kremer/kenkremer.com
The location of M49, in proximity to other Messier Objects and major stars. Credit: Wikisky
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at Orion’s Nebula’s “little brother”, the De Marian’s Nebula!
During the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the Messier Catalog) would come to include 100 of the most fabulous objects in the night sky.
One of these objects is the elliptical galaxy known as Messier 49 (aka. NGC 4472). Located in the southern skies in the constellation of Virgo, this galaxy is one several members of the Virgo Cluster of galaxies and is located 55.9 million light years from Earth. On a clear night, and allowing for good light conditions, it can be seen with binoculars or a small telescope, and will appear as a hazy patch in the sky.
Description:
Messier 49 is the brightest of the Virgo Cluster member galaxies, which is pretty accurate considering it’s only about 60 million light years away and may span an area as large as 160,000 light years. It is a huge system of globular clusters, much less concentrated than Virgo cluster member M87 – but a giant none the less. As Stephen E. Zep (et al) wrote in a 2000 study:
“We present new radial velocities for 87 globular clusters around the elliptical galaxy NGC 4472 and combine these with our previously published data to create a data set of velocities for 144 globular clusters around NGC 4472. We utilize this data set to analyze the kinematics of the NGC 4472 globular cluster system. The new data confirm our previous discovery that the metal-poor clusters have significantly higher velocity dispersion than the metal-rich clusters in NGC 4472. The very small angular momentum in the metal-rich population requires efficient angular momentum transport during the formation of this population, which is spatially concentrated and chemically enriched. Such angular momentum transfer can be provided by galaxy mergers, but it has not been achieved in other extant models of elliptical galaxy formation that include dark matter halos. We also calculate the velocity dispersion as a function of radius and show that it is consistent with roughly isotropic orbits for the clusters and the mass distribution of NGC 4472 inferred from X-ray observations of the hot gas around the galaxy.”
This ground-based image shows the Small Magellanic Cloud. The area of the SMIDGE survey is highlighted, as well as the position of NGC 248. Credit: NASA/ESA/Hubble/Digitized Sky Survey 2
However, there was something going on in the mass structure of M49 that astronomers were curious about… Something they couldn’t quite explain. Was it dark matter? As M. Lowenstein wrote in a 1992 study:
“An attempt to constrain the total mass distribution of the well-observed giant elliptical galaxy NGC 4472 is realized by constructing simultaneous equilibrium models for the gas and stars using all available relevant optical and X-ray data. The value of <?>, the emission-weighted average value of kT, derived from the Ginga spectrum, <?> = 1.9 ± 0.2 keV, can be reproduced only in hydrostatic models where nonluminous matter comprises at least 90% of the total mass. However, in general, these mass models are not consistent with observed projected stellar and globular cluster velocity dispersions at moderate radii.”
The next thing you know, nuclear outburst were discovered – the product of interaction with a neighboring galaxy. As B. Biller (et al) indicated in a 2004 study:
“We present the analysis of the Chandra ACIS observations of the giant elliptical galaxy NGC 4472. The Chandra Observatory’s arcsec resolution reveals a number of new features. Specifically: 1) an ~8 arc min streamer or arm (this corresponds to a linear size of 36 kpc) extending southwest of the galaxy and an assymetrical, somewhat truncated streamer to the northeast. Smaller, morphologically similar structures are observed in NGC 4636 and are explained as shocks from a nuclear outburst in the recent past. The larger size of the NGC 4472 streamers requires a correspondingly higher energy input compared to the NGC 4636 case. The asymmetry of the streamers may be due to the interaction of NGC 4472 with the ambient Virgo cluster gas. 2) A string of small, extended sources south of the nucleus. These sources may stem from an interaction of NGC 4472 with the galaxy UGC 7637. 3) X-ray cavities corresponding to radio lobes, where expanding radio plasma has evacuated the X-ray emitting gas. We also present a luminosity function for the X-ray point sources detected within NGC 4472 which we compare to that for other early type galaxies.”
Chandra images showing 4 of the 9 galaxies discovered (left), and an artist’s impression on showing how gas falls towards a black hole and becomes a rapidly spinning disk of matter near the center (right). Credit: NASA/Chandra
But the very best was yet to come… the discovery of a black hole! According to NASA, the results from NASA’s Chandra X-ray Observatory, combined with new theoretical calculations, provide one of the best pieces of evidence yet that many supermassive black holes are spinning extremely rapidly. The images on the left show 4 out of the 9 large galaxies included in the Chandra study, each containing a supermassive black hole in its center.
The Chandra images show pairs of huge bubbles, or cavities, in the hot gaseous atmospheres of the galaxies, created in each case by jets produced by a central supermassive black hole. Studying these cavities allows the power output of the jets to be calculated. This sets constraints on the spin of the black holes when combined with theoretical models. The Chandra images were also used to estimate how much fuel is available for each supermassive black hole, using a simple model for the way matter falls towards such an object.
The artist’s impression on the right side of the main graphic shows gas within a “sphere of influence” falling straight inwards towards a black hole before joining a rapidly spinning disk of matter near the center. Most of the material in this disk is swallowed by the black hole, but some of it is swept outwards in jets (colored blue) by quickly spinning magnetic fields close to the black hole.
Previous work with these Chandra data showed that the higher the rate at which matter falls towards these supermassive black holes, the higher their power output is in jets. However, without detailed theory the implications of this result for black hole behavior were unclear. The new study uses these Chandra results combined with leading theoretical models for the production of jets, plus general relativity, to show that the supermassive black holes in these galaxies must be spinning at close to the maximum rate. If black holes are spinning at this limit, material can be dragged around them at close to the speed of light, the speed limit from Einstein’s theory of relativity.
Atlas Image obtained of Messier 49, taken by the Two Micron All Sky Survey (2MASS). Credit: NASA/UofMass/IPAC/Caltech/NASA/NSF/2MASS
History of Observation:
According to SEDS, M49 was the first member of the Virgo cluster of galaxies to be discovered, by Charles Messier, who cataloged it on February 19th, 1771. As he recorded in his notes at the time:
“Nebula discovered near the star Rho Virginis. One cannot see it without difficulty with an ordinary telescope of 3.5-feet [FL]. The Comet of 1779 was compared by M. Messier with this nebula on April 22 and 23: The comet and the nebula had the same light. M. Messier has reported this nebula on the chart of the route of the comet, which appeared in the volume of the Academy of the same year 1779. Seen again on April 10, 1781.” Eight years later, on April 22, 1779, on the occasion of following the comet of that year, and on the hunt for finding more nebulous objects in competition to other observers, Barnabas Oriani independently rediscovered this ‘nebula’: “Very pale and looking exactly like the comet [1779 Bode, C/1779 A1].”
In his Bedford Catalogue of 1844, Admiral William H. Smyth confused this finding with Messier’s discovery:
“A bright, round, and well-defined nebula, on the Virgin’s left shoulder; exactly on the line between Delta Virginis and Beta Leonis, 8deg, or less than half-way, from the former star. With an eyepiece magnifying 93 times, there are only two telescopic stars in the field, one of which is in the sp and the other in the sf quadrant; and the nebula has a very pearly aspect. This object was discovered by Oriani in 1771 [this is wrong: it was Messier who discovered it that year; Oriani found it only in 1779], and registered by Messier as a “faint nebula, not seen without difficulty,” with a telescope of 3 1/2 feet in length. It is a pity that this active and very assiduous astronomer could not have been furnished with one of the giant telescopes of the present days. Had he possessed efficient means, there can be no doubt of the augmentation of his useful and, in its day, unique Catalogue: a collection of objects for which sidereal astronomy must ever remain indebted to him.” This error was repeated by John Herschel in his General Catalogue of 1864 (GC), who also erroneously assigned this object to “1771 Oriani,” and also found its way into J.L.E. Dreyer’s NGC.
Let’s hope you don’t mistake it with the many other galaxies nearby!
The location of Messier 49 within the Virgo constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
Locating Messier 49:
Galaxy hopping isn’t an easy chore and it takes some practice. Starting looking for M49 about halfway between Epsilon and Beta Virginis. Use Gamma to help triangulate your position. At near magnitude 8, Messier 49 is quite binocular possible and would show under dark sky conditions as a faint, very small egg shaped fog. However, it will not show in a finderscope of a telescope – but the nearby stars will.
Use their patterns to help guide you there. Because galaxies require dark skies, M49 cannot be found under urban conditions or during moonlit nights. In telescopes as small as 70mm, it will appear as a nebulous egg shape and become brighter – but no more resolved to larger instruments. To assist in location, begin with lowest magnification and increase magnification once found to darken background field.
And here are the quick facts to help you get started!
Object Name: Messier 49 Alternative Designations: M49, NGC 4472 Object Type: Elliptical Galaxy Constellation: Virgo Right Ascension: 12 : 29.8 (h:m) Declination: +08 : 00 (deg:m) Distance: 60000 (kly) Visual Brightness: 8.4 (mag) Apparent Dimension: 9×7.5 (arc min)
What a magnificent space sight to behold ! Cruise Ships and Recycled Rockets float side by side in Port Canaveral after recycled SpaceX Falcon 9 1st stage from BulgariaSat-1 launch from KSC on 23 June floats into port atop droneship on 29 June 2017. Credit: Ken Kremer/kenkremer.com
What a magnificent space sight to behold ! Cruise Ships and Recycled Rockets float side by side in Port Canaveral after recycled SpaceX Falcon 9 1st stage from BulgariaSat-1 launch from KSC on 23 June floats into port atop droneship on 29 June 2017. Credit: Ken Kremer/kenkremer.com
PORT CANAVERAL/KENNEDY SPACE CENTER, FL – The launch cadence at Elon Musk’s SpaceX is truly ramping up with Falcon 9 boosters rapidly coming and going in all directions from ground to space as the firm audaciously sets its sight on a third commercial payload orbital launch on July 2 in the span of just 9 days from its East and West Coast launch bases.
It was a magnificent sight to behold !! Seeing commercial passenger carrying cruise ships and commercial recycled rockets that will one day carry paying passenger to space, floating side by side in the busy channel of narrow Port Canaveral, basking in the suns glow from the sunshine state.
The doubly ‘flight-proven’ SpaceX Falcon 9 booster portends a promising future for spaceflight that Elon Musk hopes and plans will drastically slash the high cost of rocket launches and institute economic savings that would eventually lead to his dream of a ‘City on Mars!’ – sooner rather than later.
SpaceX Falcon 9 Booster leaning atop OCISLY droneship upon which it landed after 23 June launch from KSC floats into Port Canaveral, FL, on 29 June 2017, hauled by tugboat as seen from Jetty Park Pier. Credit: Ken Kremer/kenkremer.com
Thursday, June 29, serves as a perfect example of how SpaceX is rocking the space industry worldwide.
First, the reused first stage Falcon 9 booster from last Friday’s (June 23) SpaceX launch of the BulgariaSat-1 HD television broadcast satellite floated magnificently into Port Canaveral early Thursday morning atop the diminutive oceangoing droneship upon which it safely touched down upright on a quartet of landing legs some eight minutes after launch.
SpaceX Falcon 9 Booster leaning atop OCISLY droneship upon which it landed after 23 June launch from KSC floats into Port Canaveral, FL, on 29 June 2017, hauled by tugboat as seen from Jetty Park Pier. Credit: Ken Kremer/kenkremer.com
Second, SpaceX engineers then successfully conducted a late in the day static hot fire test of the Falcon 9 first stage engines and core that will power the next launch of the Intelsat 35e commercial comsat to orbit this Sunday, July 2.
So the day was just chock full of nonstop SpaceX rocketry action seeing a full day of rocket activities from dawn to dusk.
SpaceX Falcon 9 Booster and Canaveral Lighthouse together- Twice used SpaceX Falcon 9 which launched BulgariaSat-1 into orbit from KSC on 23 June floats into Port Canaveral with Cape Canaveral LIghthouse seen between landing legs in the distance as OCISLY drone ship crew on which she landed are working on deck on June 29, 2017. Credit: Ken Kremer/kenkremer.com
Thursday’s nonstop Space Coast action spanning from the north at the Kennedy Space Center and further south to Cape Canaveral Air Force Station and Port Canaveral was the culmination of space launch flow events that actually began days, weeks and months earlier.
The 156 foot- tall Falcon 9 booster had successfully landed on the tiny rectangular shaped “Of Course I Still Love You” or OCISLY droneship less than nine minutes after liftoff on Friday, June 23 on the BulgariaSat-1 flight.
That mission began with the picture perfect liftoff of the BulgariaSat-1 communications satellite for East European commercial broadband provider BulgariaSat at 3:10 p.m. EDT, or 19:10 UTC, June 23, with ignition of all nine of the ‘flight-proven’ Falcon 9 first stage engines on SpaceX’s seaside Launch Complex 39A at NASA’s Kennedy Space Center in Florida.
BulgariaSat is an affiliate of Bulsatcom, Bulgaria’s largest digital television provider.
The 15 story tall first stage touched down with a slight tilt of roughly eight degrees as a direct result of the extremely demanding landing regime.
Then after spending several post landing and launch days at sea due to stormy weather along the Florida Space Coast and to accommodate local shipping traffic and SpaceX planning needs, the booster at last neared shore from the south off the coast of Melbourne, FL.
Accompanied by a small armada of support vessels it was slowly towed to port by the Elsbeth III.
The SpaceX flotilla arrived at last at the mouth of Port Canaveral and Jetty Park Pier jutting into the Atlantic Ocean at about 830 a.m. EDT – offering a spectacular view at to a flock of space enthusiasts and photographers including this author.
SpaceX Booster arrival on 30 June 2017. Credit: Dawn Leek Taylor
I highly recommend you try and see a droneship arrival if all possible.
The leaning boosters – of which this is only the second – are even more dramatic!
Because the Falcon 9 barely survived the highest ever reentry force and landing heat to date, Musk reported.
The rectangularly shaped OCISLY droneship is tiny – barely the size of a moderately sized apartment complex parking lot.
Credit: Ken Kremer/kenkremer.com
Falcon 9’s first stage for the BulgariaSat-1 mission previously supported the Iridium-1 mission from Vandenberg Air Force Base in January of this year.
Some two minutes and 40 seconds after liftoff the first and second stages separated.
As the second stage continued to orbit, the recycled first stage began the daunting trip back to Earth on a very high energy trajectory that tested the limits of the boosters landing capability.
“Falcon 9 will experience its highest ever reentry force and heat in today’s launch. Good chance rocket booster doesn’t make it back,” SpaceX founder and CEO Elon Musk wrote in a prelaunch tweet.
Following stage separation, Falcon 9’s first stage carried out two burns, the entry burn and the landing burn using a trio of the Merlin 1D engines.
Ultimately the 15 story tall booster successfully landed on the “Of Course I Still Love You” or OCISLY droneship, stationed in the Atlantic Ocean about 400 miles (600 km) offshore and east of Cape Canaveral.
“Rocket is extra toasty and hit the deck hard (used almost all of the emergency crush core), but otherwise good,” Musk tweeted shortly after the recycled booster successfully launched and landed for its second time.
Up close view of blackened Aluminum grid fins on twice used SpaceX Falcon 9 1st stage which just sailed into Port Canaveral on 29 June after launching BulgariaSat-1 23 June 2017 from pad 39A on NASA’s Kennedy Space Center. The fins are being replaced by more resilient units made of Titanium as demonstrated 1st during the recent Iridium 2 launch. Credit: Ken Kremer/kenkremer.com
BulgariaSat-1 and Iridium-2 counted as the eighth and ninth SpaceX launches of 2017.
Including those two ocean platform landings, SpaceX has now successfully recovered 13 boosters; 5 by land and 8 by sea, over the past 18 months.
Both landing droneships are now back into their respective coastal ports.
It’s a feat straight out of science fiction but aimed at drastically slashing the cost of access to space as envisioned by Musk.
Watch my BulgariaSat-1 launch video from KSC pad 39A
Video Caption: Launch of SpaceX Falcon 9 on June 23, 2017 from pad 39A at the Kennedy Space Center carrying BulgariaSat-1 TV broadband satellite to geosynchronous orbit for BulgariaSat, which is Bulgaria’s 1st GeoComSat – as seen in this remote video taken at the pad. Credit: Ken Kremer/kenkremer.com
Watch for Ken’s onsite BulgariaSat-1 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.
Blastoff of 2nd flight-proven SpaceX Falcon 9 with 1st geostationary communications for Bulgaria at 3:10 p.m. EDT on June 23, 2017, carrying BulgariaSat-1 to orbit from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Credit: Ken Kremer/kenkremer.com
I look forward to all the future missions that NASA is going to be sending out in the Solar System. Here, check this out. You can use NASA’s website to show you all the future missions. Here’s everything planned for the future, here’s everything going to Mars.
Now, let’s look and see what missions are planned for the outer planets of the Solar System, especially Uranus and Neptune. Oh, that’s so sad… there’s nothing.
Uranus, seen by Voyager 2. Image credit: NASA/JPL
It’s been decades since humanity had an up close look at Uranus and Neptune. For Uranus, it was Voyager 2, which swept through the system in 1986. We got just a few tantalizing photographs of the ice giant planet and it’s moons.
Mosaic of the four highest-resolution images of Ariel taken by the Voyager 2 space probe during its 1986 flyby of Uranus. Credit: NASA/JPL
What’s that?
Oberon, as imaged by the Voyager 2 probe during its flyby on Jan. 24, 1986. Credit: NASA
What’s going on there?
Color composite of the Uranian satellite Miranda, taken by Voyager 2 on Jan. 24, 1986, from a distance of 147,000 km (91,000 mi). Credit: NASA/JPL
What are those strange features? Sorry, insufficient data.
And then Voyager 2 did the same, zipping past Neptune in 1989.
Reconstruction of Voyager 2 images showing the Great Black spot (top left), Scooter (middle), and the Small Black Spot (lower right). Credit: NASA/JPL
Check this out.
Neptune’s largest moon Triton photographed on August 25, 1989 by Voyager 2. Credit: NASA
What’s going here on Triton? Wouldn’t you like to know more? Well, too bad! You can’t it’s done, that’s all you get.
Don’t get me wrong, I’m glad we’ve studied all these other worlds. I’m glad we’ve had orbiters at Mercury, Venus, everything at Mars, Jupiter, and especially Saturn. We’ve seen Ceres and Vesta, and the Moon up close. We even got a flyby of Pluto and Charon.
It’s time to go back to Uranus and Neptune, this time to stay.
And I’m not the only one who feels this way.
Scientists at NASA recently published a report called the Ice Giant Mission Study, and it’s all about various missions that could be sent to explore Uranus, Neptune and their fascinating moons.
The team of scientists who worked on the study considered a range of potential missions to the ice giants, and in the end settled on four potential missions; three that could go to Uranus, and one headed for Neptune. Each of them would cost roughly $2 billion.
Uranus is closer, easier to get to, and the obvious first destination of a targeted mission. For Uranus, NASA considered three probes.
The first idea is a flyby mission, which will sweep past Uranus gathering as much science as it can. This is what Voyager 2 did, and more recently what NASA’s New Horizons did at Pluto. In addition, it would have a separate probe, like the Cassini and Galileo missions, that would detach and go into the atmosphere to sample the composition below the cloudtops. The mission would be heavy and require an Atlas V rocket with the same configuration that sent Curiosity to Mars. The flight time would take 10 years.
NASA’s Curiosity Mars Science Laboratory (MSL) rover blasts off for Mars atop a stunningly beautiful Atlas V rocket. Credit: Ken Kremer – kenkremer.com
The main science goal of this mission would be to study the composition of Uranus. It would make some other measurements of the system as it passed through, but it would just be a glimpse. Better than Voyager, but nothing like Cassini’s decade plus observations of Saturn.
I like where this is going, but I’m going to hold out for something better.
The next idea is an orbiter. Now we’re talking! It would have all the same instruments as the flyby and the detachable probe. But because it would be an orbiter, it would require much more propellant. It would have triple the launch mass of the flyby mission, which means a heavier Atlas V rocket. And a slightly longer flight time; 12 years instead of 10 for the flyby.
Because it would remain at Uranus for at least 3 years, it would be able to do an extensive analysis of the planet and its rings and moons. But because of the atmospheric probe, it wouldn’t have enough mass for more instruments. It would have more time at Uranus, but not a much better set of tools to study it with.
Okay, let’s keep going. The next idea is an orbiter, but without the detachable probe. Instead, it’ll have the full suite of 15 scientific instruments, to study Uranus from every angle. We’re talking visible, doppler, infrared, ultraviolet, thermal, dust, and a fancy wide angle camera to give us those sweet planetary pictures we like to see.
Study Uranus? Yes please. But while we’re at it, let’s also sent a spacecraft to Neptune.
The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into a equivalent 95 minute exposure, and the ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute).
As part of the Ice Giants Study, the researchers looked at what kind of missions would be possible. In this case, they settled on a single recommended mission. A huge orbiter with an additional atmospheric probe. This mission would be almost twice as massive as the heaviest Uranus mission, so it would need a Delta IV Heavy rocket to even get out to Neptune.
As it approached Neptune, the mission would release an atmospheric probe to descend beneath the cloudtops and sample what’s down there. The orbiter would then spend an additional 2 years in the environment of Neptune, studying the planet and its moons and rings. It would give us a chance to see its fascinating moon Triton up close, which seems to be a captured Kuiper Belt Object.
Unfortunately there’s no perfect grand tour trajectory available to us any more, where a single spacecraft could visit all the large planets in the Solar System. Missions to Uranus and Neptune will have to be separate, however, if NASA’s Space Launch System gets going, it could carry probes for both destinations and launch them together.
The goal of these missions is the science. We want to understand the ice giants of the outer Solar System, which are quite different from both the inner terrestrial planets and the gas giants Jupiter and Saturn.
The Solar System. Credit: NASA
The gas giants are mostly hydrogen and helium, like the Sun. But the ice giants are 65% water and other ices made from methane and ammonia. But it’s not like they’re big blobs of water, or even frozen water. Because of their huge gravity, the ice giants crush this material with enormous pressure and temperature.
What happens when you crush water under this much pressure? It would all depend on the temperature and pressure. There could be different types of ice down there. At one level, it could be an electrically conductive soup of hydrogen and oxygen, and then further down, you might get crystallized oxygen with hydrogen ions running through it.
Hailstones made of diamond could form out of the carbon-rich methane and fall down through the layers of the planets, settling within a molten carbon core. What I’m saying is, it could be pretty strange down there.
We know that ice giants are common in the galaxy, in fact, they’ve made up the majority of the extrasolar planets discovered so far. By better understanding the ones we have right here in our own Solar System, we can get a sense of the distant extrasolar planets turning up. We’ll be better able to distinguish between the super earths and mini-neptunes.
Artist’s impression of the Milky Way’s 100 billion exoplanets. Credit: NASA, ESA, and M. Kornmesser (ESO)
Another big question is how these planets formed in the first place. In their current models, most planetary astronomers think these planets had very short time windows to form. They needed to have massive enough cores to scoop up all that material before the newly forming Sun’s solar wind blasted it all out into space. And yet, why are these kinds of planets so common in the Universe?
The NASA mission planners developed a total of 12 science objectives for these missions, focusing on the composition of the planets and their atmospheres. And if there’s time, they’d like to know about how heat moves around, their constellations of rings and moons. They’d especially like to investigate Neptune’s moons Triton, which looks like a captured Kuiper Belt Object, as it orbits in the reverse direction from all the other moons in the Solar System.
In terms of science, the two worlds are very similar. But because Neptune has Triton. If I had to choose, I’d go with a Neptune mission.
Neptune and its large moon Triton as seen by Voyager 2 on August 28th, 1989. (Credit: NASA).
Are you excited? I’m excited. Here’s the bad news. According to NASA, the best launch windows for these missions would be 2029 or 2034. And that’s just the launch time, the flight time is an additional decade or more on top of that. In other words, the first photos from a Uranus flyby could happen in 2039 or 2035, while orbiters could arrive at either planet in the 2040s. I’m sure my future grandchildren will enjoy watching these missions arrive.
But then, we have to keep everything in perspective. NASA’s Cassini mission was under development in the 1980s. It didn’t launch until 1997, and it didn’t get to Saturn until 2004. It’s been almost 20 years since that launch, and almost 40 years since they started working on it.
I guess we need to be more patient. I can be patient.
Picture of the asteroid that exploded over Cherlyabinsk on Feb 15, 2013. Credit: Tuvix/Youtube
Every day, Earth is hit by 60 to 300 metric tons of space dust and smaller meteoroids. But sometimes, larger and more dangerous space rocks plummet to Earth, such as on June 30, 1908 when an estimated 40 meter-wide meteoroid exploded over the Tunguska, Siberia region in Russia, devastating 2000 sq. kilometers (770 square miles) of forest. As the 2013 Chelyabinsk meteor event attests, the likelihood of a similar event happening again is not an “if” but a “when.”
To raise public awareness about asteroid impact hazards and to urge political leaders to work together to be prepared, the United Nations proclaimed June 30 as International Asteroid Day.
A first-ever 24-hour Asteroid Day program will be feature nearly 1,000 events around the world. It starts at 9 p.m. EDT on June 29 (1 a.m. June 30 GMT), streaming online at the Asteroid Day webcast.
The events start in Tucson, Arizona with an event hosted by our friend, Meteorite Man and Action Scientist Geoff Notkin speaking with Dante Lauretta and Heather Enos from the OSIRIS-REx mission to asteroid Bennu, Eric Christensen, director, Catalina Sky Survey for Near-Earth Objects and many more.
Other events around the world feature Brian Cox, Neil deGrasse Tyson, Brian May, Peter Gabriel, as well as dozens of expert scientists, technologists and researchers in planetary science, NASA astronauts Rusty Schweickart, Ed Lu and Nicole Stott, ESA astronauts Michel Tognini, Jean-François Clervoy; and Romanian astronaut Dorin Prunariu.
In addition, the Discovery Channel, has produced two specials about asteroids and Asteroid Day to air June 30 around the world: “How to Survive an Asteroid Impact” and a three-minute Virtual Reality video that re-enacts the Tunguska event, provides viewers with an insight into the risks of asteroids, how scientists are trying to protect our planet, and what viewers should do if an asteroid is about to impact their city.
According to a press release from Asteroid Day, central to Asteroid Day is the 100x Declaration, calling for the 100-fold increase in the detection and monitoring of asteroids. Signed to date by more than 60,000 people around the world, the Declaration resolves to “solve humanity’s greatest challenges to safeguard our families and quality of life on Earth in the future. The Declaration is available online for the signature of anyone concerned about advancing asteroid research and technology.
MESSENGER image of Mercury from its third flyby (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
The Solar Planets are a nice mixed bag of what is possible when it comes to planetary formation. Within the inner Solar System, you have the terrestrial planets – bodies that are composed primarily of silicate minerals and metals. And in the outer Solar System, you have the gas giants and bodies that are composed primarily of ice that lie just beyond in the Trans-Neptunian region.
Of these, the question of which planet is the smallest has been the subject of some controversy. Until recently, the smallest planet was considered to be Pluto. But with the 2006 IAU Resolution that put constraints on what the definition of a planet entails, that status has since passed to Mercury. So in addition to being the closest planet to the Sun, Mercury is also the smallest.
Size and Mass:
With a mean radius of 2440 km, Mercury is the smallest planet in our Solar System, equivalent in size to 0.38 Earths. And given that it has its experiences no flattening at the poles – like Venus, which means it is an almost perfectly spherical body – its radius is the same at the poles as it is the equator.
And while it is smaller than the largest natural satellites in our Solar System – such as Ganymede and Titan – it is more massive. At 3.3011×1023 kg in mass (33 trillion trillion metric tons; 36.3 trillion trillion US tons), it is equivalent to 0.055 Earths in terms of mass.
Mercury and Earth, size comparison. Credit: NASA / APL (from MESSENGER)
Density, Volume:
On top of that, Mercury is significantly more dense than bodies its size. In fact, Mercury’s density (at 5.427 g/cm3) is the second highest in the Solar System, only slightly less than Earth’s (5.515 g/cm3). The result of this is a gravitational force of 3.7 m/s2, which is 0.38 times that of Earth (0.38 g). In essence, this means that if you could stand on the surface of Mercury, you would weight 38% as much as you do on Earth.
In terms of volume, Mercury once again becomes a bit diminutive, at least by Earth standards. Basically, Mercury has a volume of 6.083×1010 km³ (60 billion cubic km; 14.39 trillion cubic miles) which works out to 0.056 times the volume of the Earth. In other words, you could fit Mercury inside Earth almost twenty times over.
Structure and Composition:
Like Earth, Venus and Mars, Mercury is a terrestrial planet, meaning that is primarily composed of silicate minerals and metals that are differentiated between a metallic core and a silicate mantle and crust. But in Mercury’s case, the core is oversized compared to the other terrestrial planets, measuring some 1,800 km (approx. 1,118.5 mi) in radius, and therefore occupying 42% of the planet’s volume (compared to Earth’s 17%).
Internal structure of Mercury: 1. Crust: 100–300 km thick 2. Mantle: 600 km thick 3. Core: 1,800 km radius. Credit: MASA/JPL
Another interesting feature about Mercury’s core is the fact that it has a higher iron content than that of any other major planet in the Solar System. Several theories have been proposed to explain this, the most widely-accepted being that Mercury was once a larger planet that was struck by a planetesimal that stripped away much of the original crust and mantle, leaving behind the core as a major component.
Beyond the core is a mantle that measures 500 – 700 km (310 – 435 mi) in thickness and is composed primarily of silicate material. The outermost layer is Mercury’s crust, which is composed of silicate material that is believed to be 100 – 300 km thick.
Yes, Mercury is a pretty small customer when compared to its brothers, sisters and distant cousins in the Solar System. However, it is also one of the densest, hottest and most irradiated. So while small, no one would ever accuse this planet of not being really tough!
