Posted on by Matt Williams

Saturn’s Hexagon Will be the Star of the Cassini Finale

This illustration shows Cassini above Saturn's northern hemisphere prior to one of its 22 Grand Finale dives. Credit: NASA/JPL-Caltech

The Cassini spacecraft is nearing the end of its lifespan. This September, after spending the past twenty years in space – twelve and a half of which were dedicated to studying Saturn and its system of moons – the probe will be crash into Saturn’s atmosphere. But between now and then, the probe will be making its “Grand Finale” – the final phase of its mission where it will dive between the planet and its rings 22 times.

In addition to exploring this region of Saturn (something no other mission has done), the probe will also be using this opportunity to study Saturn’s hexagonal polar jet stream in greater detail. This persistent storm, which rages around Saturn’s northern polar region, has been a subject of interest for decades. And now that it enjoys full sunlight, Cassini will be able to directly image it with every pass it makes over Saturn’s north pole.

This persistent storm was first noticed in images sent back by the Voyager 1 and 2 missions, which flew by Saturn in 1980 and 1981, respectively. As storms go, it is extremely massive, with each side measuring about 13,800 km (8,600 mi) in length – longer than the diameter of the Earth. It also rotates with a period of 10 hours 39 minutes and 24 seconds, which is assumed to be equal to the rotation of Saturn’s interior.

Image of Saturn’s hexagonal polar jet stream, taken by Cassini on Jan. 22nd, 2017. Credit: NASA/JPL-Caltech/Space Science Institute

When the Cassini spacecraft arrived around Saturn in 2004 to conduct the first part of its mission, this region was in shadow. This was due to the fact that the northern hemisphere was still coming out of winter, and was hence tilted  away from the Sun. However, since Saturn began its summer solstice in May of 2017, the northern polar region is now fully illuminated – at least by Saturn’s standards.

In truth, between its distance from the Sun (an average of 9.5549 AU) and its axial tilt (26.73°), the northern polar region only gets about 1% as much sunlight as Earth does. And from the perspective of the north pole, the Sun is very low in the sky. Nevertheless, the sunlight falling on the north pole at this point is enough to allow the Cassini mission to directly image the region by capturing its reflected light.

Images of the hexagonal jet stream (like the one above) will be taken by Cassini’s wide-angle camera, which uses special filters that admit wavelengths of near-infrared light. Already, Cassini has captured some impressive imagery during its first plunge between Saturn and its rings (which took place on April 26th, 2017). The rapid-fire images acquired by one of Cassini’s cameras were then stitched together to create a movie (posted below).

As you can see, the movie begins with a view of the vortex at the center of the hexagon, then heads past the outer boundary of the jet stream and continues further southward. Toward the end of the movie, the spacecraft reorients itself to direct its saucer-shaped antenna in the direction of the spacecraft’s motion, which is apparent from the way the camera frame rotates.

The images that make up this movie were captured as the Cassini spacecraft dropped in altitude from 72,400 to 6,700 km (45,000 to 4,200 miles) above Saturn’s cloud tops. As this happened, the features which the camera could resolve changed drastically – going from 8.7 km (5.4 mi) per pixel to 810 meters (0.5 mi) per pixel.

The movie was produced by Kunio Sayanagi and John Blalock – an associate of the Cassini imaging team and a  graduate research assistant (respectively) at Hampton University in Virginia – who collaborated with the Cassini imaging team. And thanks to this video, new insights are already being made into the hexagonal jet stream and the mechanisms that power it.

For example, as Sayanagi indicated in a NASA press release, the video captured the boundary regions of the jet stream rather nicely, which allowed him to note an interesting fact about them. “I was surprised to see so many sharp edges along the hexagon’s outer boundary,” he said. “Something must be keeping different latitudes from mixing to maintain those edges.”

Andrew Ingersoll, a member of the Cassini imaging team based at Caltech, expressed how similar movies will result from future plunges taken as part of the Grand Finale. “The images from the first pass were great, but we were conservative with the camera settings,” he said. “We plan to make updates to our observations for a similar opportunity on June 29th that we think will result in even better views.”

Between now and the end of the mission, who knows what we might learn about this mysterious storm? The next plunge – aka. Grand Finale Dive No. 4 – will take place on Sunday, May 15th at 4:42 p.m. UTC (12:42 p.m EDT; 9:42 a.m. PDT). A total of 22 dives will be made on a weekly basis before the probe takes the final plunge – the one that will cause it to breakup in Saturn’s atmosphere – on Friday, September 15th, 2017.

For more information, consult Cassini’s Grand Finale Orbit Guide. And be sure to enjoy this video of the final phase of the probe’s mission, courtesy of NASA:

Further Reading: NASA, NASA/JPL

Posted on by Matt Williams

Newly Discovered House-Sized Asteroid 2017 HX4 Flew Safely Past the Earth Yesterday

Mining asteroids might be necessary for humanity to expand into the Solar System. But what effect would asteroid mining have on the world's economy? Credit: ESA.

Yesterday (on May 8th, 2017), an asteroid swung past Earth on its way towards the Sun. This Near Earth Object (NEO), known as 2017 HX4, measures between 10 and 33 meters (32.8 and 108 feet) and made its closest approach to Earth at 11:58 am UT (7:58 am EDT; 4:58 am PT). Naturally, there were surely those who wondered if this asteroid would hit us and trigger a terrible cataclysm!

But of course, like most NEOs that periodically make a close pass to Earth, 2017 HX4 passed us by at a very safe distance. In fact, the asteroid’s closest approach to Earth was estimated to be at a distance of 3.7 Lunar Distances (LD) – i.e. almost four times the distance between the Earth and the Moon. This, and other pertinent information was tweeted in advance by the International Astronomical Union’s Minor Planet Center (IAU MPC) on April 29th.

This object was first spotted on April 26th, 2017, using the 1.8 meter Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), located at the summit of Haleakala in Hawaii. Since that time, it has been monitored by multiple telescopes around the world, and its tracking data and information about its orbit and other characteristics has been provided by the IAU MPC.

Interactive Orbit Sketch, showing the orbit of the Near Earth Object (NEO) known as 2017 HX4. Credit: IAU MPC

With funding provided by NASA’s Near-Earth Object Observations program, the IAU MPC maintains a centralized database that is responsible for the identification, designation and orbit computations of all the minor planets, comets and outer satellites of the Solar System. Since it’s inception, it has been maintaining information on 16,202 Near-Earth Objects, 729,626 Minor Planets, and 3,976 comets.

But it is the NEOs that are of particular interest, since they periodically make close approaches to Earth. In the case of 2017 HX4, the object has been shown to have an orbital period of 2.37 years, following a path that takes it from beyond the orbit of Venus to well beyond the orbit of Mars. In other words, it orbits our Sun at an average distance (semi-major axis) of 1.776 AU, ranging from about 0.88 AU at perihelion to 2.669 AU at aphelion.

Since it was first spotted, the object has been viewed a total of 41 times between April 26th and May 4th. In addition to the Pan-STARRS-1 survey, observations were also provided by the Cerro Tololo Observatory, the Mauna Kea Observatories, the Steward Observatory and the Kitt Peak-Spacewatch Telescopes, the Astronomical Research Observatory, the Apache Point Observatory, and the Mount John Observatory.

PS1 at dawn. The mountain in the distance is Mauna Kea, about 130 kilometers southeast. Credit: pan-starrs.ifa.hawaii.edu

From these combined observations, the IAU MPC was able to compile information on the object’s orbital period, when it would cross Earth’s orbit, and just how close it would come to us in the process. So, as always, there was nothing to worry about here folks. These objects are always spotted before they cross Earth’s orbit, and their paths, periods and velocities and are known about in advance.

Even so, it’s worth noting that an object of this size was nowhere near to be large enough to cause an Extinction Level Event. In fact, the asteroid that struck Earth 65 millions year ago at the end of Cretaceous era – which created the Chicxulub Crater on the Yucatan Peninsula in Mexico and caused the extinction of the dinosaurs – was estimated to measure 10 km across.

At 10 to 33 meters (32.8 to 108 feet), this asteroid would certainly have caused considerable damage if it hit us. But the results would not exactly have been cataclysmic. Still, it might not be too soon to consider getting off this ball of rock. You know, before – as Hawking has warned – a single event is able to claim all of humanity in one fell swoop!

The MPC is currently tracking the 13 NEOs that were discovered during the month of May alone, and that’s just so far. Expect to hear more about rocks that might cross our path in the future.

Further Reading: IAU Minor Planet Center

Posted on by Matt Williams

Does Jupiter Have a Solid Core?

Damian Peach reprocessed one of the latest images taken by Juno's JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights two large 'pearls' or storms in Jupiter's atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS

The gas giants have always been a mystery to us. Due to their dense and swirling clouds, it is impossible to get a good look inside them and determine their true structure. Given their distance from Earth, it is time-consuming and expensive to send spacecraft to them, making survey missions few and far between. And due to their intense radiation and strong gravity, any mission that attempts to study them has to do so carefully.

And yet, scientists have been of the opinion for decades that this massive gas giant has a solid core. This is consistent with our current theories of how the Solar System and its planets formed and migrated to their current positions. Whereas the outer layers of Jupiter are composed primarily of hydrogen and helium, increases in pressure and density suggest that closer to the core, things become solid.

Structure and Composition:

Jupiter is composed primarily of gaseous and liquid matter, with denser matter beneath. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.

upiter's structure and composition. (Image Credit: Kelvinsong CC by S.A. 3.0)
Jupiter’s structure and composition. Credit: Kelvinsong CC by S.A. 3.0

The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds, as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.

The interior contains denser materials, such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The core has also been described as rocky, but this remains unknown as well.

In 1997, the existence of the core was suggested by gravitational measurements, indicating a mass of 12 to 45 times the mass of Earth, or roughly 4%–14% of the total mass of Jupiter. The presence of a core is also supported by models of planetary formation that indicate how a rocky or icy core would have been necessary at some point in the planet’s history. Otherwise, it would not have been able to collect all of its hydrogen and helium from the protosolar nebula – at least in theory.

However, it is possible that this core has since shrunk due to convection currents of hot, liquid, metallic hydrogen mixing with the molten core. This core may even be absent now, but a detailed analysis is needed before this can be confirmed. The Juno mission, which launched in August 2011 (see below), is expected to provide some insight into these questions, and thereby make progress on the problem of the core.

Formation and Migration:

Our current theories regarding the formation of the Solar System claim that the planets formed about 4.5 billion years ago from a Solar Nebula (i.e. Nebular Hypothesis). Consistent with this theory, Jupiter is believed to have formed as a result of gravity pulling swirling clouds of gas and dust together.

Jupiter acquired most of its mass from material left over from the formation of the Sun, and ended up with more than twice the combined mass of the other planets. In fact, it has been conjectured that it Jupiter had accumulated more mass, it would have become a second star. This is based on the fact that its composition is similar to that of the Sun – being made predominantly of hydrogen.

Artist’s concept of a young star surrounded by a disk of gas and dust – called a protoplanetary disk. Credit: NASA/JPL-Caltech

In addition, current models of Solar System formation also indicate that Jupiter formed farther out from its current position. In what is known as the Grand Tack Hypothesis, Jupiter migrated towards the Sun and settled into its current position by roughly 4 billion years ago. This migration, it has been argued, could have resulted in the destruction of the earlier planets in our Solar System – which may have included Super-Earths closer to the Sun.

Exploration:

While it was not the first robotic spacecraft to visit Jupiter, or the first to study it from orbit (this was done by the Galileo probe between 1995 and 2003), the Juno mission was designed to investigate the deeper mysteries of the Jovian giant. These include Jupiter’s interior, atmosphere, magnetosphere, gravitational field, and the history of the planet’s formation.

The mission launched in August 2011 and achieved orbit around Jupiter on July 4th, 2016. The probe entered its polar elliptical orbit after completing a 35-minute-long firing of the main engine, known as Jupiter Orbital Insertion (or JOI). As the probe approached Jupiter from above its north pole, it was afforded a view of the Jovian system, which it took a final picture of before commencing JOI.

Since that time, the Juno spacecraft has been conducting perijove maneuvers – where it passes between the northern polar region and the southern polar region – with a period of about 53 days. It has completed 5 perijoves since it arrived in June of 2016, and it is scheduled to conduct a total of 12 before February of 2018. At this point, barring any mission extensions, the probe will de-orbit and burn up in Jupiter’s outer atmosphere.

As it makes its remaining passes, Juno will gather more information on Jupiter’s gravity, magnetic fields, atmosphere, and composition. It is hoped that this information will teach us much about how the interaction between Jupiter’s interior, its atmosphere and its magnetosphere drives the planet’s evolution. And of course, it is hoped to provide conclusive data on the interior structure of the planet.

Does Jupiter have a solid core? The short answer is, we don’t know… yet. In truth, it could very well have a solid core composed of iron and quartz, which is surrounded by a thick layer of metallic hydrogen. It is also possible that interaction between this metallic hydrogen and the solid core caused the the planet to lose it some time ago.

The South Pole of Jupiter, taken during the Juno mission’s third orbit (Perijove 3). Credits: NASA/JPL-Caltech/SwRI/MSSS/ Luca Fornaciari © cc nc sa

At this point, all we can do is hope that ongoing surveys and missions will yield more evidence. These are not only likely to help us refine our understanding of Jupiter’s internal structure and its formation, but also refine our understanding of the history of the Solar System and how it came to be.

We have written many articles about Jupiter for Universe Today. Here Ten Interesting Facts About Jupiter, How Big is Jupiter?, How Long Does it Take to get to Jupiter?, What is the Weather Like on Jupiter?, How Far is Jupiter from the Sun?, and The Orbit of Jupiter. How Long is a Year on Jupiter?

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.

Sources:

Posted on by Matt Williams

Only 10 Light-Years Away, there’s a Baby Version of the Solar System

Artist's impression of the Epsilon Eridani system, showing Epsilon Eridani b (a Jupiter-mass planet) and a series of asteroid belts and comets. Credit: NASA/SOFIA/Lynette Cook.

Astronomers are understandanly fascinated with the Epsilon Eridani system. For one, this star system is in close proximity to our own, at a distance of about 10.5 light years from the Solar System. Second, it has been known for some time that it contains two asteroid belts and a large debris disk. And third, astronomers have suspected for many years that this star may also have a system of planets.

On top of all that, a new study by a team of astronomers has indicated that Epsilon Eridani may be what our own Solar System was like during its younger days. Relying on NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft, the team conducted a detailed analysis of the system that showed how it has an architecture remarkably similar to what astronomer believe the Solar System once looked like.

Led by Kate Su – an Associate Astronomer with the Steward Observatory at the University of Arizona – the team includes researchers and astronomers from the Department of Physics & Astronomy of Iowa State University, the Astrophysical Institute and University Observatory at the University of Jena (Germany), and NASA’s Jet Propulsion Laboratory and Ames Research Center.

Artist’s diagram showing the similar structure of the Epsilon Eridani to the Solar System. Credit: NASA/JPL-Caltech

For the sake of their study – the results of which were published in The Astronomical Journal under the title “The Inner 25 AU Debris Distribution in the Epsilon Eri System” – the team relied on data obtained by a flight of SOFIA in January 2015. Combined with detailed computer modeling and research that went on for years, they were able to make new determinations about the structure of the debris disk.

As already noted, previous studies of Epsilon Eridani indicated that the system is surrounded by rings made up of materials that are basically leftovers from the process of planetary formation. Such rings consist of gas and dust, and are believed to contain many small rocky and icy bodies as well – like the Solar System’s own Kuiper Belt, which orbits our Sun beyond Neptune.

Careful measurements of the disk’s motion has also indicated that a planet with nearly the same mass as Jupiter circles the star at a distance comparable to Jupiter’s distance from the Sun. However, based on prior data obtained by the NASA’s Spitzer Space Telescope, scientists were unable to determine the position of warm material within the disk – i.e. the dust and gas – which gave rise to two models.

In one, warm material is concentrated into two narrow rings of debris that orbit the star at distances corresponding respectively to the Main Asteroid Belt and Uranus in our Solar System. According to this model, the largest planet in the system would likely be associated with an adjacent debris belt. In the other, warm material is in a broad disk, is not concentrated into asteroid belt-like rings, and is not associated with any planets in the inner region.

NASA’s SOFIA aircraft before a 2015 flight to observe a nearby star. Credit: Massimo Marengo.

Using the new SOFIA images, Su and her team were able to determine that the warm material around Epsilon Eridani is arranged like the first model suggests. In essence, it is in at least one narrow belt, rather than in a broad continuous disk. As Su explained in a NASA press release:

“The high spatial resolution of SOFIA combined with the unique wavelength coverage and impressive dynamic range of the FORCAST camera allowed us to resolve the warm emission around eps Eri, confirming the model that located the warm material near the Jovian planet’s orbit. Furthermore, a planetary mass object is needed to stop the sheet of dust from the outer zone, similar to Neptune’s role in our solar system. It really is impressive how eps Eri, a much younger version of our solar system, is put together like ours.”

These observations were made possible thanks to SOFIA’s on-board telescopes, which have a greater diameter than Spitzer – 2.5 meters (100 inches) compared to Spitzer’s 0.85 m (33.5 inches). This allowed for far greater resolution, which the team used to discern details within the Epsilon Eridani system that were three times smaller than what had been observed using the Spitzer data.

In addition, the team made use of SOFIA’s powerful mid-infrared camera – the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). This instrument allowed the team to study the strongest infrared emissions coming from the warm material around the star which are otherwise undetectable by ground-based observatories – at wavelengths between 25-40 microns.

This artist’s conception of the Epsilon Eridani system, the closest star system who’s structure resembles a young Solar System. Credit: NASA/JPL/Caltech

These observations further indicate that the Epsilon Eridani system is much like our own, albeit in younger form. In addition to having asteroid belts and a debris disk that is similar to our Main Belt and Kuiper Belt, it appears that it likely has more planets waiting to be found within the spaces between. As such, the study of this system could help astronomers to learn things about the history of our own Solar System.

Massimo Marengo, one of he co-authors of the study, is an Associate Professor with the Department of Physics & Astronomy at Iowa State University. As he explained in a University of Iowa press release:

“This star hosts a planetary system currently undergoing the same cataclysmic processes that happened to the solar system in its youth, at the time in which the moon gained most of its craters, Earth acquired the water in its oceans, and the conditions favorable for life on our planet were set.”

At the moment, more studies will need to be conducted on this neighboring stars system in order to learn more about its structure and confirm the existence of more planets. And it is expected that the deployment of next-generation instruments – like the James Webb Space Telescope, scheduled for launch in October of 2018 – will be extremely helpful in that regard.

“The prize at the end of this road is to understand the true structure of Epsilon Eridani’s out-of-this-world disk, and its interactions with the cohort of planets likely inhabiting its system,” Marengo wrote in a newsletter about the project. “SOFIA, by its unique ability of capturing infrared light in the dry stratospheric sky, is the closest we have to a time machine, revealing a glimpse of Earth’s ancient past by observing the present of a nearby young sun.”

Further Reading: NASA, IAState, The Astronomical Journal

Posted on by Matt Williams

Faster Supercomputer! NASA Announces the High Performance Fast Computing Challenge

Looking to the future of space exploration, NASA and TopCoder have launched the "High Performance Fast Computing Challenge" to improve the performance of their Pleiades supercomputer. Credit: NASA/MSFC

For decades, NASA’s Aeronautics Research Mission Directorate (ARMD) has been responsible for developing the technologies that put satellites into orbit, astronauts on the Moon, and sent robotic missions to other planets. Unfortunately, after many years of supporting NASA missions, some of their machinery is getting on in years and is in need of an upgrade.

Consider the Pleiades supercomputer, the distributed-memory machine that is responsible for conducting modeling and simulations for NASA missions. Despite being one of the fastest supercomputers in the world, Pleiades will need to be upgraded in order to stay up to task in the years ahead. Hence why NASA has come together with TopCoder (and with the support of HeroX) to launch the High Performance Fast Computing Challenge (HPFCC).

With a prize purse of $55,000, NASA and TopCoder are seeking programmers and computer specialists to help them upgrade Pleiades so it can perform computations faster. Specifically, they want to improve its FUN3D software so that flow analysis which previously took months can now be done in days or hours. In short, they want to speed up their supercomputers by a factor of 10 to 1000 while relying on its existing hardware, and without any decreases in accuracy.

The addition of Haswell processors in 2015 increased the theoretical peak processing capability of Pleiades from 4.5 petaflops to 5.3 petaflops. Credit: NASA

Those hoping to enter need to be familiar with FUN3D software, which is used to calculate the nonlinear partial differential equations (aka. Navier-Stokes equations) that are used for steady and unsteady flow computations. These include large eddy simulations in computational fluid dynamics (CFD), which are of particular importance when it comes to supersonic aircraft, space flight, and the development launch vehicles and planetary reentry systems.

NASA has partnered to launch this challenge with TopCoder, the world’s largest online community of designers, developers and data scientists. Since it was founded in 2001, this company has hosted countless online competitions (known as “single round matches”, or SRMs) designed to foster better programming. They also host weekly competitions to stimulate developments in graphic design.

Overall, the HPFSCC will consist of two challenges – the Ideation Challenge and the Architecture Challenge. For the Ideation Challenge (hosted by NASA), competitors must propose ideas that can help optimize the Pleiades source code. As they state, may include (but is not limited to) “exploiting algorithmic developments in such areas as grid adaptation, higher-order methods and efficient solution techniques for high performance computing hardware.”

The computation of fluid dynamics is of particular importance when plotting space launches and reentry. Credit: NASA/JPL-Caltech

The Architecture Challenge (hosted by TopCoder), is focused less on strategy and more on measurable improvements. As such, participants will be tasked with showing how to optimize processing in order to reduce the overall time and increase the efficiency of computing models. Ideally, says TopCoder, this would include “algorithm optimization of the existing code base, inter-node dispatch optimization, or a combination of the two.”

NASA is providing $20,000 in prizes for the Ideation challenge, with $10,000 awarded for first place, and two runner-up awards of $5000 each. TopCoder, meanwhile, is offering $35,000 for the Architecture challenge – a top prize of $15,000 for first place, $10,000 for second place, with $10,000 set aside for the Qualified Improvement Candidate Prize Pool.

The competition will remain open to submissions until June 29th, 2017, at which point, the judging will commence. This will wrap up on August 7th, and the winners of both competitions will be announced on August 9th. So if you are a coder, computer engineer, or someone familiar with FUN3D software, be sure to head on over to HeroX and accept the challenge!

Human space exploration continues to advance, with missions planned for the Moon, Mars, and beyond. With an ever-expanding presence in space and new challenges awaiting us, it is necessary that we have the right tools to make it all happen. By leveraging improvements in computer programming, we can ensure that one of the most important aspects of mission planning remains up to task!

Further Reading: HeroX, TopCoder

Posted on by Matt Williams

High-Speed Space Broadband for Everyone. SpaceX Details their Plans to Launch 1000s of Internet Satellites

A number companies are deploying satellites this year to create space-based internet services. Credit: AMNH.

SpaeeX and Tesla-founder Elon Musk has made some rather bold promises over the years. In addition to building a fleet of reusable rockets, an Interplanetary Transport System, colonizing Mars, and revolutionizing transportation, he has also made it clear that he hopes to provide worldwide broadband access by deploying a “constellation” of internet-providing satellites.

In November of 2016, SpaceX filed an application with the Federal Communications Commission (FCC) for a license to operate this constellation of non-geostationary satellites (NGS). And earlier this week, the US Senate Committee on Commerce. Science, and Transportation convened a hearing to explore this proposal for next-generation telecommunications services.

The hearing was titled, “Investing in America’s Broadband Infrastructure: Exploring Ways to Reduce Barriers to Deployment”. In the course of things, the committee heard from representatives of government and industry who spoke about the best ways to offer streamlined broadband access (especially in rural areas), the necessary infrastructure, and how to encourage private investment.

SpaceX’s proposed satellite constellation – 4,425 broadband internet satellites – could provide the entire world with high-speed internet access. Credit: ESA

Of those the committee heard from, Ms. Patricia Cooper – VP of Satellite Government Affairs for SpaceX – was on hand to underscore the company’s vision. As she stated:

“SpaceX sees substantial demand for high-speed broad band in the United States and worldwide. As the Committee is aware, millions of Americans outside of limited urban areas lack basic, reliable access. Furthermore, even in urban areas, a majority of Americans lacks more than a single fixed broadband provider from which to choose and may seek additional competitive options for high-speed service.”

Cooper also cited recent FCC findings, which indicated that millions of Americans lag behind other developed nations in terms of broadband speed, access, and price competitiveness. Basically, thirty-four million American citizens do not have access to 25 megabits per second (“Mbps”) broadband service while 47% of students in the US lack the connectivity to meet the FCC’s short-term goal of 100 Mbps per 1,000 students and staff.

This is at at a time when global demand for broadband services and internet connectivity continue to grow at an unprecedented rate. According to a report prepared by Cisco in 2016 – titled “White paper: Cisco VNI Forecast and Methodology, 2015-2020” – global Internet Protocol (IP) traffic surpassed the zettabyte threshold. In other words, over 1,000 billion gigabytes of data were exchanged worldwide in a single year!

SpaceX plans to beginning launching their internet-providing satellites aboard their Falcon 9 rockets beginning next year. Credit: Ken Kremer/Kenkremer.com

By 2020, that figure is projected to double, global fixed broadband speeds are expected to nearly double, and the number of devices connected to IP networks is projected to outnumber the global population by a factor of about 3 to 1. To remedy this situation, and bring broadband access in the US up to the average for developed nations, SpaceX plans to launch 4,425 broadband satellites.

These will begin being launched in 2019 aboard the company’s fleet of Falcon 9 rockets. The launches will continue until they have reached full capacity, which is expected to be by 2024. As Cooper outlined it:

“Later this year, SpaceX will begin the process of testing the satellites themselves, launching one prototype before the end of the year and another during the early months of 2018. Following successful demonstration of the technology, SpaceX intends to begin the operational satellite launch campaign in 2019. The remaining satellites in the constellation will be launched in phases through 2024, when the system will reach full capacity with the Ka- and Ku-Band satellites. SpaceX intends to launch the system onboard our Falcon 9 rocket, leveraging significant launch cost savings afforded by the first stage reusability now demonstrated with the vehicle.”

Other details included the operational altitudes of the satellites – ranging from 1,110 to 1,325 km (690 to 823 mi) – as well as the necessary infrastructure on the ground, which would include “ground control facilities, gateway Earth stations, and end-user Earth stations.” SpaceX has also indicated that it plans to deploy an additional 7.500 satellites that will operate at lower altitudes in order to boost broadband capacity in large population centers.

Naturally, there have to be those people who hear words like “satellite constellation” and immediately think “space junk”. Certainly, the deployment of between 4,425 and 11,925 satellites in the coming years will lead to increasing concerns about “orbital clutter”. Especially when other telecommunications providers are seeking to get in on the trend – a good example being Google’s Project Loon.

Why Space Debris Mitigation is needed. Credit: ESA

And while the subject did not come up during the hearing, it will be unavoidable in the coming years and decades. But in the meantime, the idea of bringing internet access to the world – particularly the developing regions of the world where the infrastructure may not otherwise exist – has the potential of being a great social leveler. In the coming decades, it is expected that internet use will reach proportions unheard of a few decades ago.

By 2020 alone, it is estimated that the number of Internet users will reach almost 5 billion – or roughly half the world projected population of 10 billion. This represents an almost threefold increase from the number of internet users in 2010 (1.7 billion) and an almost 14 fold increase since 2000 (360 million). As such, any investment that will help ensure that this growth occurs more equally across geographic and social barriers is certainly a good one.

The committee also heard testimony from Larry Downes, the Project Director of the Georgetown Center for Business and Public Policy, and Brian Hendricks – the head of Technology Policy & Public Affairs for the Americas Region for Nokia. In addition to addressing the current sate of broadband internet in the US, they made multiple recommendations on how the non-geostationary internet satellite industry could be fostered and developed.

You can read the transcripts and check out the live webcast by going to the hearing page.

Further Reading: US SCCST

Posted on by Matt Williams

Titan Ripe For Drone Invasion

A proposed eight-bladed drone (aka. "dragonfly") could be ideally suited for exploring Saturn's moon Titan in the coming decades. Credit: APL/Michael Carroll

With its dense and hydrocarbon-rich atmosphere, Titan has been a subject of interest for many decades. And with the success of the Cassini-Huygens mission, which began exploring Saturn and its system of moons back in 2004, there are many proposals on the table for follow-up missions that would explore the surface of Titan and its methane seas in greater depth.

The challenges that this presents have led to some rather novel ideas, ranging from balloons and landers to floating drones and submarines. But it is the proposal for a “Dragonfly” drone by researchers at NASA’s JHUAPL that seems  particularly adventurous. This eight-bladed drone would be capable of vertical-takeoff and landing (VTOL), enabling it to explore both the atmosphere and the surface of Titan in the coming decades.

The mission concept was proposed by a science team led by Elizabeth Turtle, a planetary scientist from NASA’s Johns Hopkins University Applied Physics Laboratory (JHUAPL). Back in February, the concept was presented at the “Planetary Science Vision 2050 Workshop” – which took place at NASA’s headquarters in Washington, DC – and again in late March at the 48th Lunar and Planetary Science Conference in The Woodlands, Texas.

ASA’s Cassini spacecraft looks toward the night side of Saturn’s largest moon and sees sunlight scattering through the periphery of Titan’s atmosphere and forming a ring of color.
Credit: NASA/JPL-Caltech/Space Science Institute

Such a mission, as Turtle explained to Universe Today via email, is both timely and necessary. Not only would it build on many recent developments in robotic explorers (such as the Curiosity rover and the Cassini orbiter); but on Titan, there is simply no shortage of opportunities for scientific research. As she put it:

“Titan’s an ocean world with a unique twist, which is the rich and complex organic chemistry occurring in its atmosphere and on its surface. This combination makes Titan a particularly good target for studying planetary habitability. One of the big questions about the development of life is how chemical interactions led to biological processes. Titan’s been doing experiments in prebiotic chemistry for millions of years – timescales that are impossible to reproduce in the lab – and the results of these experiments are there to be collected.”

Their proposal is based in part on previous Decadal Surveys, such as the Campaign Strategy Working Group (CSWG) on Prebiotic Chemistry in the Outer Solar System. This survey emphasized that a mobile aerial vehicle (i.e an airship or a balloon) would well-suited to exploring Titan. Not only is Titan the only known body other than Earth that has a dense, nitrogen-rich atmosphere –  four times as dense as Earth’s – but it’s gravity is also about 1/7th that of Earth’s.

However, balloons and airships would be unable to study Titan’s methane lakes, which are one of the most exciting draws as far as research into prebiotic chemistry goes. What’s more, an aerial vehicle would not be able to conduct in-situ chemical analysis of the surface, much like what the Mars Exploration Rovers (Spirit, Opportunity and Curiosity) have been doing on Mars.

Artist’s concept of a Titan Aerial Daughter quadcopter and its “Mothership” balloon. Credit: NASA/STMD

As such, Turtle and her colleagues began looking for a proposal that represented the best of both worlds – i.e. an aerial platform and a lander. This was the genesis of the Dragonfly concept.

“Several different methods have been considered for in-situ aerial exploration of Titan (helicopters, different types of balloons, airplanes),” said Turtle. “Dragonfly takes advantage of the recent developments in multi-rotor aircraft to provide aerial mobility for a lander with a sophisticated payload.  Because Dragonfly would be able to travel long distances – a few tens of kilometers at a time, and up to a few hundred kilometers over the course of the mission – it would be possible to make measurements at multiple sites with very different geologic histories.”

The mission is also in keeping with concepts that Turtle and her colleagues – which includes Ralph Lorenz (also from JHUAPL), Melissa Trainer of the Goddard Space Flight Center, and Jason Barnes of University of Idaho – have been exploring for years. In the past, they proposed a mission concept that would combine a Montgolfière-style balloon with a Pathfinder-like lander. Whereas the balloon would explore Titan from a low altitude, the lander would explore the surface up close.

By the 48th Lunar and Planetary Science Conference, they had officially unveiled their “Dragonfly” concept, which called for a qaudcopter to conduct both aerial and surface studies. This four-rotor vehicle, it was argued, would be able to take advantage of Titan’s thick atmosphere and low gravity to obtain samples and determine surface compositions in multiple geological settings.

Artist’s concept of the dragonfly being deployed to Titan and commencing its exploration mission. Credit: APL/Michael Carroll

In its latest iteration, the Dragonfly incorporates eight rotors (two positioned at each of its four corners) to achieve and maintain flight. Much like the Curiosity and upcoming Mars 2020 rovers, the Dragonfly would be powered by a Multimission Radioisotope Thermoelectric Generator (MMRTG). This system uses the heat generated by decaying plutonium-238 to generate electricity, and can keep a robotic mission going for years.

This design, says Turtle, would offer scientists the ideal in-situ platform for studying Titan’s environment:

“Dragonfly would be able to measure compositional details of different surface materials, which would show how far organic chemistry has progressed in different environments.  These measurements could also reveal chemical signatures of water-based life (like that on Earth) or even hydrocarbon-based life, if either were present on Titan.  Dragonfly would also study Titan’s atmosphere, surface, and sub-surface to understand current geologic activity, how materials are transported, and the possibility of exchange of organic material between the surface and the interior water ocean.”

This concept incorporates a lot of recent advances in technology, which include modern control electronics and advances in commercial unmanned aerial vehicle (UAV) designs. On top of that, the Dragonfly would do away with chemically-powered retrorockets and could power-up between flights, giving it a potentially much longer lifespan.

The view from the beach on Titan? Image: NASA
Artist’s impression of the view from the surface of Titan, looking over one of its methane seas. Credit: NASA

“And now is the perfect time,” says Turtle, “because we can build on what we’ve learned from the Cassini-Huygens mission to take the next steps in Titan exploration.”

Currently, NASA’s Jet Propulsion Laboratory is developing a similar concept. Known as the Mars Helicopter “Scout”, for use on Mars, this aerial drone is expected to be launched aboard the Mars 2020 mission. In this case, the design calls for two coaxial counter-rotating rotors, which would provide the best thrust-to-weight ratio in Mars’ thin atmosphere.

This sort of VTOL platform could become the mainstay in the coming decades, wherever long-term missions that involve bodies that have atmospheres are called for. Between Mars and Titan, such aerial drones could hop from one area to the next, obtaining samples for in-situ analysis and combining surface studies with atmospheric readings at various altitudes to get a more complete picture of the planet.

Further Reading: USRA, LPI, Space

Posted on by Matt Williams

New Japanese mission will be going to the Moons of Mars

Artist's impression of the Mars Moons Exploration (MMX) spacecraft. Credit: JAXA

In the coming decades, the world’s largest space agencies hope to mount some exciting missions to the Moon and to Mars. Between NASA, Roscosmos, the European Space Agency (ESA), the Chinese National Space Agency (CNSA) and the Indian Space Research Organization (ISRO), there is simply no shortage of proposals for Lunar bases, crewed missions to Mars, and robotic explorers to both.

However, the Japanese Aerospace Exploration Agency (JAXA) has a different mission in mind when it comes to the coming decades. Instead of exploring the Moon or Mars, they propose exploring the moons of Mars! Known as the Martian Moons Exploration (MMX) mission, the plan is to have a robotic spacecraft fly to Phobos and Deimos to explore their surfaces and return samples to Earth for analysis.

Continue reading “New Japanese mission will be going to the Moons of Mars”
Posted on by Matt Williams

Building Rovers That Can Detect Life and Sequence DNA on Other Worlds

An interdisciplinary team from MIT (with support from NASA) is seeking to create an instrument that can performing in-situ test for life. Credit: setg.mit.edu

In 2015, then-NASA Chief Scientist Ellen Stofan stated that, “I believe we are going to have strong indications of life beyond Earth in the next decade and definite evidence in the next 10 to 20 years.” With multiple missions scheduled to search foe evidence of life (past and present) on Mars and in the outer Solar System, this hardly seems like an unrealistic appraisal.

But of course, finding evidence of life is no easy task. In addition to concerns over contamination, there is also the and the hazards the comes with operating in extreme environments – which looking for life in the Solar System will certainly involve. All of these concerns were raised at a new FISO conference titled “Towards In-Situ Sequencing for Life Detection“, hosted by Christopher Carr of MIT.

Carr is a research scientist with MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS) and a Research Fellow with the Department of Molecular Biology at Massachusetts General Hospital. For almost 20 years, he has dedicated himself to the study of life and the search for it on other planets. Hence why he is also the science principal investigator (PI) of the Search for Extra-Terrestrial Genomes (SETG) instrument.

This artist’s rendering shows NASA’s Europa mission spacecraft, which will search for life on Europa beginning sometime in the 2020s. Credit: NASA/JPL-Caltech

Led by Dr. Maria T. Zuber – the E. A. Griswold Professor of Geophysics at MIT and the head of EAPS – the inter-disciplinary group behind SETG includes researchers and scientists from MIT, Caltech, Brown University, arvard, and Claremont Biosolutions. With support from NASA, the SETG team has been working towards the development of a system that can test for life in-situ.

Introducing the search for extra-terrestrial life, Carr described the basic approach as follows:

“We could look for life as we don’t know it. But I think it’s important to start from life as we know it – to extract both properties of life and features of life, and consider whether we should be looking for life as we know it as well, in the context of searching for life beyond Earth.”

Towards this end, the SETG team seeks to leverage recent developments in in-situ biological testing to create an instrument that can be used by robotic missions. These developments include the creation of portable DNA/RNA testing devices like the MinION, as well as the Biomolecule Sequencer investigation. Performed by astronaut Kate Rubin in 2016, this was first-ever DNA sequencing to take place aboard the International Space Station.

Building on these, and the upcoming Genes in Space program – which will allow ISS crews to sequence and research DNA samples on site – the SETG team is looking to create an instrument that can isolate, detect, and classify any DNA or RNA-based organisms in extra-terrestrial environments. In the process, it will allow scientists to test the hypothesis that life on Mars and other locations in the Solar System (if it exists) is related to life on Earth.

The theory of Lithopanspermia states that life can be shared between planets within a planetary system. Credit: NASA

To break this hypothesis down, it is a widely accepted theory that the synthesis of complex organics – which includes nucleobases and ribose precursors – occurred early in the history of the Solar System and took place within the Solar nebula from which the planets all formed. These organics may have then been delivered by comets and meteorites to multiple potentially-habitable zones during the Late Heavy Bombardment period.

Known as lithopansermia, this theory is a slight twist on the idea that life is distributed throughout the cosmos by comets, asteroids and planetoids (aka. panspermia). In the case of Earth and Mars, evidence that life might be related is based in part on meteorite samples that are known to have come to Earth from the Red Planet. These were themselves the product of asteroids striking Mars and kicking up ejecta that was eventually captured by Earth.

By investigating locations like Mars, Europa and Enceladus, scientists will also be able to engage in a more direct approach when it comes to searching for life. As Carr explained:

“There’s a couple main approaches. We can take an indirect approach, looking at some of the recently identified exoplanets. And the hope is that with the James Webb Space Telescope and other ground-based telescopes and space-based telescopes, that we will be in a position to begin imaging the atmospheres of exoplanets in much greater detail than characterization of those exoplanets has [allowed for] to date. And that will give us high-end, it will give the ability to look at many different potential worlds. But it’s not going to allow us to go there. And we will only have indirect evidence through, for example, atmospheric spectra.”

Enceladus in all its glory. NASA has announced that Enceladus, Saturn’s icy moon, has hydrogen in its oceans. Image: NASA/JPL/Space Science Institute

Mars, Europa and Enceladus present a direct opportunity to find life since all have demonstrated conditions that are (or were) conducive to life. Whereas there is ample evidence that Mars once had liquid water on its surface, Europa and Enceladus both have subsurface oceans and have shown evidence of being geologically active. Hence, any mission to these worlds would be tasked with looking in the right locations to spot evidence of life.

On Mars, Carr notes, this will come down to looking in places there there is a water-cycle, and will likely involve some a little spelunking:

“I think our best bet is to access the subsurface. And this is very hard. We need to drill, or otherwise access regions below the reach of space radiation which could destroy organic materiel. And one possibility is to go to fresh impact craters. These impact craters could expose material that wasn’t radiation-processed. And maybe a region where we might want to go would be somewhere where a fresh impact crater could connect to a deeper subsurface network – where we could get access to material perhaps coming out of the subsurface. I think that is probably our best bet for finding life on Mars today at the moment. And one place we could look would be within caves; for example, a lava tube or some other kind of cave system that could offer UV-radiation shielding and maybe also provide some access to deeper regions within the Martian surface.”

As for “ocean worlds” like Enceladus, looking for signs of life would likely involve exploring around its southern polar region where tall plumes of water have been observed and studied in the past. On Europa, it would likely involve seeking out “chaos regions”, the spots where there may be interactions between the surface ice and the interior ocean.

Exploring Europa’s “chaos terrain”, where the is interaction between the interior ocean and the surface ice, could yield evidence of biological organisms. Credit: NASA/JPL-Caltech

Exploring these environments naturally presents some serious engineering challenges. For starters, it would require the extensive planetary protections to ensure that contamination was prevented. These protections would also be necessary to ensure that false positives were avoided. Nothing worse than discovering a strain of DNA on another astronomical body, only to realize that it was actually a skin flake that fell into the scanner before launch!

And then there are the difficulties posed by operating a robotic mission in an extreme environment. On Mars, there is always the issue of solar radiation and dust storms. But on Europa, there is the added danger posed by Jupiter’s intense magnetic environment. Exploring water plumes coming from Enceladus is also very challenging for an orbiter that would most likely be speeding past the planet at the time.

But given the potential for scientific breakthroughs, such a mission it is well worth the aches and pains. Not only would it allow astronomers to test theories about the evolution and distribution of life in our Solar System, it could also facilitate the development of crucial space exploration technologies, and result in some serious commercial applications.

Looking to the future, advances in synthetic biology are expected to lead to new treatments for diseases and the ability to 3-D print biological tissues (aka. “bioprinting”). It will also help ensure human health in space by addressing bone density loss, muscle atrophy, and diminished organ and immune-function. And then there’s the ability to grow organisms specially-designed for life on other planets (can you say terraforming?)

Exogenesis
Is life in our Solar System, and the Universe for that matter, universal in nature? Credit: NASA/Jenny Mottor

On top of all that, the ability to conduct in-situ searches for life on other Solar planets also presents scientists with the opportunity to answer a burning question, one which they’ve struggled with for decades. In short, is carbon-based life universal? So far, any and all attempts to answer this question have been largely theoretical and have involved the “low hanging fruit variety” – where we have looked for signs of life as we know it, using mainly indirect methods.

By finding examples that come from environments other than Earth, we would be taking some crucial steps towards preparing ourselves for the kinds of “close encounters” that could be happening down the road.

Further Reading: SETG, FISO

Posted on by Matt Williams

NASA’s Space Chainmail to Give Astronauts the Edge in Space Duels

This metallic "space fabric" was created using 3-D printed techniques that add different functionality to each side of the material. Credits: NASA/JPL-Caltech

One would think NASA was preparing for a some sword fights in space! At least, that’s the impression one might get when they see the new armor NASA is developing for the first time. Officially, they are referring to it as a new type of “space fabric“, one which will provide protection to astronauts, spaceships and deployable devices. But to the casual observer, it looks a lot like chain mail armor!

The new armor is the brainchild of Polit Casillas, a systems engineer from NASA’s Jet Propulsion Laboratory. Inspired by traditional textiles, this armor relies on advances made in additive manufacturing (aka. 3-D printing) to create woven metal fabrics that can fold and change shape quickly. And someday soon, it could be used for just about everything!

As the son of a fashion designer in Spain, Casillas grew up around fabrics and textiles, and was intrigued by how they are used for the sake of design. Much in the same way that textiles are produced by weaving together countless threads, Casilla’s prototype space fabric relies on 3-D printing to create metal squares in one piece, which are then strung together to form a coat of armor.

Another example of a 3-D-printed metallic “space fabric.” The bottom and top sides of the fabric are designed to have different functionality. Credits: NASA/JPL-Caltech

In addition to his work with this new space fabric, Casillas co-leads JPL’s Atelier workshop, which specialized in the rapid-prototyping of advanced concepts and systems. This fast-paced collaborative environment works with different technologies and looks for ways to incorporate new ones (such as 4-D printing) into existing designs. As Casillas described this concept in a NASA press release:

“We call it ‘4-D printing’ because we can print both the geometry and the function of these materials. If 20th Century manufacturing was driven by mass production, then this is the mass production of functions.”

The space fabrics have four essential functions, which includes reflectivity, passive heat management, foldability and tensile strength. With one side reflecting light and the other absorbing it, the material acts as a means of thermal control. It can also fold in many different ways and adapt to shapes, all the while maintaining tensile strength to ensure it can sustain forces pulling on it.

These fabrics could be used to protect astronauts and shield large antennas, deployable devices and spacecraft from meteorites and other hazards. In addition, they could be used to ensure that missions to extreme environments would be protected from the elements. Consider Jupiter’s moon Europa, which NASA is planning on exploring in the coming decade using a lander – aka. the Europa Clipper mission.

Artist’s concept of a Europa Clipper mission. Credit: NASA/JPL

Here, and on other “ocean worlds” – like Ceres, Enceladus, Titan and Pluto – this sort of flexible armor could provide insulation for spacecraft. They could be used on landing struts to ensure that they could change shape to fit over uneven terrain as well. This kind of material could also be used to build habitats for Mars or the Moon – like the South Pole-Aitken Basin, where permanently-shadowed craters allow for the existence of water ice.

Another benefit of this material is the fact that it is considerably cheaper to produce compared to materials made using traditional fabrication methods. Under ordinary conditions, designing and building spacecraft is a complex and costly process. But by adding multiple functions to a material at different stages of development, the whole process can be made cheaper and new designs can be implemented.

Andrew Shapiro-Scharlotta is a manager at the JPL’s Space Technology Office, an office responsible for funding  early-stage technologies like the space fabric. As he put it, this sort of production process could enable all kinds of designs and new mission concepts. “We are just scratching the surface of what’s possible,” he said. “The use of organic and non-linear shapes at no additional costs to fabrication will lead to more efficient mechanical designs.”

In keeping with how 3-D printing has been developed for use aboard the ISS, the JPL team not only wants to use this fabric in space, but also manufacture it in space as well. In the future, Casillas also envisions a process whereby tools and structural materials can be printed from recycled materials, offering additional cost-savings and enabling rapid, on-demand production of necessary components.

Such a production process could revolutionize the way spacecraft and space systems are created. Instead of ships, suits, and robotic craft created from many different parts (which then have to be assembled), they could be printed out like “whole cloth”. The manufacturing revolution, it seems, loometh!

Further Reading: NASA