Posted on by Matt Williams

Dawn Probe Finds Evidence of Subsurface Ice on Vesta

Artist's concept of the Dawn spacecraft arriving at Vesta. Image credit: NASA/JPL-Caltech

In 2011, NASA’s Dawn spacecraft established orbit around the large asteroid (aka. planetoid) known as Vesta. Over the course of the next 14 months, the probe conducted detailed studies of Vesta’s surface with its suite of scientific instruments. These findings revealed much about the planetoid’s history, its surface features, and its structure – which is believed to be differentiated, like the rocky planets.

In addition, the probe collected vital information on Vesta’s ice content. After spending the past three years sifting through the probe’s data, a team of scientists has produced a new study that indicates the possibility of subsurface ice. These findings could have implications when it comes to our understanding of how Solar bodies formed and how water was historically transported throughout the Solar System.

Their study, titled “Orbital Bistatic Radar Observations of Asteroid Vesta by the Dawn Mission“, was recently published in the scientific journal Nature Communications. Led by Elizabeth Palmer, a graduate student from Western Michigan University, the team relied on data obtained by the communications antenna aboard the Dawn spacecraft to conduct the first orbital bistatic radar (BSR) observation of Vesta.

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

This antenna – the High-Gain telecommunications Antenna (HGA) – transmitted X-band radio waves during its orbit of Vesta to the Deep Space Network (DSN) antenna on Earth. During the majority of the mission, Dawn’s orbit was designed to ensure that the HGA was in the line of sight with ground stations on Earth. However, during occultations – when the probe passed behind Vesta for 5 to 33 minutes at a time – the probe was out of this line of sight.

Nevertheless, the antenna was continuously transmitting telemetry data, which caused the HGA-transmitted radar waves to be reflected off of Vesta’s surface. This technique, known as bistatic radar (BSR) observations has been used in the past to study the surfaces of terrestrial bodies like Mercury, Venus, the Moon, Mars, Saturn’s moon Titan, and the comet 67P/CG.

But as Palmer explained, using this technique to study a body like Vesta was a first for astronomers:

“This is the first time that a bistatic radar experiment was conducted in orbit around a small body, so this brought several unique challenges compared to the same experiment being done at large bodies like the Moon or Mars. For example, because the gravity field around Vesta is much weaker than Mars, the Dawn spacecraft does not have to orbit at a very high speed to maintain its distance from the surface. The orbital speed of the spacecraft becomes important, though, because the faster the orbit, the more the frequency of the ‘surface echo’ gets changed (Doppler shifted) compared to the frequency of the ‘direct signal’ (which is the unimpeded radio signal that travels directly from Dawn’s HGA to Earth’s Deep Space Network antennas without grazing Vesta’s surface). Researchers can tell the difference between a ‘surface echo’ and the ‘direct signal’ by their difference in frequency—so with Dawn’s slower orbital speed around Vesta, this frequency difference was very small, and required more time for us to process the BSR data and isolate the ‘surface echoes’ to measure their strength.”

This high-res geological map of Vesta is derived from Dawn spacecraft data. Brown colors represent the oldest, most heavily cratered surface. Credit: NASA/JPL-Caltech/ASU

By studying the reflected BSR waves, Palmer and her team were able to gain valuable information from Vesta’s surface. From this, they observed significant differences in surface radar reflectivity. But unlike the Moon, these variations in surface roughness could not be explained by cratering alone and was likely due to the existence of ground-ice. As Palmer explained:

“We found that this was the result of differences in the roughness of the surface at the scale of a few inches.  Stronger surface echoes indicate smoother surfaces, while weaker surface echoes have bounced off of rougher surfaces. When we compared our surface roughness map of Vesta with a map of subsurface hydrogen concentrations—which was measured by Dawn scientists using the Gamma Ray and Neutron Detector (GRaND) on the spacecraft—we found that extensive smoother areas overlapped areas that also had heightened hydrogen concentrations!”

In the end, Palmer and her colleagues concluded that the presence of buried ice (past and/or present) on Vesta was responsible for parts of the surface being smoother than others. Basically, whenever an impact happened on the surface, it transferred a great deal of energy to the subsurface. If buried ice was present there, it would be melted by the impact event, flow to the surface along impact-generated fractures, and then freeze in place.

Much in the same way that moon’s like Europa, Ganymede and Titania experience surface renewal because of the way cryovolcanism causes liquid water to reach the surface (where it refreezes), the presence of subsurface ice would cause parts of Vesta’ surface to be smoothed out over time. This would ultimately lead to the kinds of uneven terrain that Palmer and her colleagues witnessed.

The planetoid Vesta, which was studied by the Dawn probe between July 2011 and September 2012. Credit: NASA

This theory is supported by the large concentrations of hydrogen that were detected over smoother terrains that measure hundreds of square kilometers. It is also consistent with geomorphological evidence obtained from the Dawn Framing Camera images, which showed signs of of transient water flow over Vesta’s surface. This study also contradicted some previously-held assumptions about Vesta.

As Palmer noted, this could also have implications as far as our understanding of the history and evolution of the Solar System is concerned:

“Asteroid Vesta was expected to have depleted any water content long ago through global melting, differentiation, and extensive regolith gardening by impacts from smaller bodies. However, our findings support the idea that buried ice may have existed on Vesta, which is an exciting prospect since Vesta is a protoplanet that represents an early stage in the formation of a planet. The more we learn about where water-ice exists throughout the Solar System, the better we will understand how water was delivered to Earth, and how much was intrinsic to Earth’s interior during the early stages of its formation.”

This work was sponsored by NASA’s Planetary Geology and Geophysics program, a JPL-based effort that focuses on fostering the research of terrestrial-like planets and major satellites in the Solar System. The work was also conducted with the assistance of the USC’s Viterbi School of Engineering as part of an ongoing effort to improve radar and microwave imaging to locate subsurface sources of water on planets and other bodies.

Further Reading: USC, Nature Communications

Posted on by Ken Kremer

Northrop Grumman Acquires Orbital ATK for $9.2 Billion

Antares rocket stands erect, reflecting off the calm waters the night before a launch from NASA’s Wallops Flight Facility, VA, on Oct. 28, 2014. Credit: Ken Kremer/kenkremer.com
Orbital ATK Antares rocket stands erect, reflecting off the calm waters the night before a launch from NASA’s Wallops Flight Facility, VA, on Oct. 28, 2014. Credit: Ken Kremer/kenkremer.com

Aerospace giant Northrop Grumman will acquire Orbital ATK for approximately $9.2 billion, in a deal the companies announced Monday and they say will “expand capability” is largely “complementary” and involves “little overlap.”

Orbital ATK specializes in a wide variety of launch vehicles, satellites, missiles and munitions that Northrop believes will significantly enhance capabilities it lacks while offering Orbital significantly more technical and financial resources to grow sales and business opportunities.

Under the terms of the huge deal West Falls Church, Virginia based Northrop will dole out approximately $7.8 billion in cash to buy Dulles, Virginia based Orbital ATK and assume $1.4 billion in net debt. Orbital ATK shareholders will receive all-cash consideration of $134.50 per share, which is about a 20% premium above the stock’s price of $110 per share at the close of trading Friday, Sept. 15.

Rumors of the deal first appeared on Sunday.

Orbital Sciences Corporation Antares rocket and Cygnus spacecraft blasts off on July 13 2014 from Launch Pad 0A at NASA Wallops Flight Facility , VA, on the Orb-2 mission and loaded with over 3000 pounds of science experiments and supplies for the crew aboard the International Space Station. Credit: Ken Kremer – kenkremer.com

The final purchase is expected to take place around mid-2018, subject to approval by government regulators and Orbital ATK shareholders.

The Boards of Directors of both companies have already given unanimous approval to the mega buyout.

“Our two companies represent a very complementary fit,” Wes Bush, chief executive officer and president of Northrop Grumman said in a conference call on Monday, Sept. 18.

“We have very little overlap, and we fully expect our combined portfolios of leading technologies, along with our aligned and innovation-focused cultures, to yield significant value creation through revenue, cost and operational synergies, accelerating our profitable growth trajectory.”

Northrop indicated that Orbital ATK will operate as a separate fourth unit – at least initially – and that Orbital programs will benefit from the increased financial resources available from Northrup.

“Upon completion of the acquisition, Northrop Grumman plans to establish Orbital ATK as a new, fourth business sector to ensure a strong focus on operating performance and a smooth transition into Northrop Grumman.”

For his part Orbital ATK CEO David Thompson was very pleased with the buyout and future opportunities.

“The agreement reflects the tremendous value that Orbital ATK has created for our customers, our shareholders and our employees,” David Thompson, Orbital ATK president and chief executive officer said at the conference call.

“The combination will allow our team as a new business sector within Northrop Grumman to maintain strong operational performance on existing customer programs and to pursue new opportunities that require greater technical and financial resources than we currently possess.”

“Our collective customers should benefit from the expanded capabilities for innovation, increased speed of delivery and improved affordability of production resulting from the combination.”

“The combination of our companies and human capital will also significantly benefit our customers,” Bush elaborated. “Together, we can offer our customers enhanced mission capabilities and more competitive offerings in areas such as space, missiles and strategic deterrents.

“Our shareholders can expect revenue synergies from these new business opportunities.”

Northrop Grumman sales for 2017 amount to about $25 billion vs. about $4.5 billion for Orbital ATK
Orbital ATK itself is the product of a very recent merger in 2015 of Orbital Sciences and ATK.

The company employs over 13,000 people including over 4,200 scientists and engineers. It holds a heft backlog of contracts worth more than $15 billion.

Northrop Grumman employs over 68,000 people and is the fifth largest defense contractor.

“The agreement will also provide expanded career options for our employees as part of a larger, more diverse aerospace and defense company,” said Thompson.

It will also benefit stockholders.

“The transaction represents a truly compelling financial proposition for our shareholders, valuing the enterprise at about $9.2 billion and providing our investors with more than 120% total return over the 3-year period from the completion of the Orbital ATK merger in early 2015 to the expected closing in the first half of 2018.”

Orbital ATK Minotaur IV rocket streaks to orbit through low hanging clouds that instantly illuminate as the booster engines flames pass through. This first Minotaur launch from the Cape carried the ORS-5 satellite tracker to equatorial orbit for the U.S. Air Force at 2:04 a.m. EDT on August 26, 2017 from Cape Canaveral Air Force Station in Florida. Credit: Ken Kremer/kenkremer.com

Orbital ATK launchers run the gamut from small to medium to large.

The rockets include the massive solid rocket boosters for NASA’s Space Launch System (SLS) heavy lift rocket under development, the Antares liquid fueled booster used to launch Cygnus cargo freighters to the International Space Station for NASA, the Minotaur family of medium class solid rocket launchers, as well as sounding rockets for a variety of low weight science missions.

The most recent Orbital ATK launch took place on Aug. 26 when a Minotaur 4 rocket (a retired Peacekeeper ICBM) lifted off from Cape Canaveral with a USAF surveillance satellite.

Orbital ATK also has a thriving satellite manufacturing business building NASA science, commercial, government and military satellites.

Northrop Grumman is the prime contractor for NASA’s James Webb Space Telescope and designed the optics and spacecraft bus under contract for NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

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

The purchase is also estimated to result in $150 million in annual cost savings by 2020.

“We believe that this combination represents a compelling value creation opportunity for the customers, shareholders and employees of both our companies,” stated Bush. “Through our combination, all of our stakeholders will benefit from expanded capabilities, accelerated innovation and greater competitiveness in critical global security domains.”

Watch for Ken’s continuing onsite NASA mission and launch reports direct from the Kennedy Space Center, and Cape Canaveral Air Force Station, Florida, and NASA Wallops Flight Facility, Va.

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

Ken Kremer

The Orbital ATK Antares rocket, with the Cygnus OA-5 spacecraft onboard, is raised into the vertical position on launch Pad-0A for planned launch on Oct. 17, 2016, at NASA’s Wallops Flight Facility in Virginia. Credit: Ken Kremer/kenkremer
Posted on by Matt Williams

Venus Express Probe Reveals the Planet’s Mysterious Night Side

Artist's impression of the Venus Express spacecraft in orbit around Venus. Credit: ESA

Venus’ atmosphere is as mysterious as it is dense and scorching. For generations, scientists have sought to study it using ground-based telescopes, orbital missions, and the occasional atmospheric probe. And in 2006, the ESA’s Venus Express mission became the first probe to conduct long-term observations of the planet’s atmosphere, which revealed much about its dynamics.

Using this data, a team of international scientists – led by researchers from the Japan Aerospace and Exploration Agency (JAXA) – recently conducted a study that characterized the wind and upper cloud patterns on the night side of Venus. In addition to being the first of its kind, this study also revealed that the atmosphere behaves differently on the night side, which was unexpected.

The study, titled “Stationary Waves and Slowly Moving Features in the Night Upper Clouds of Venus“, recently appeared in the scientific journal Nature Astronomy. Led by Javier Peralta, the International Top Young Fellow of JAXA, the team consulted data obtained by Venus Express’ suite of scientific instruments in order to study the planet’s previously-unseen cloud types, morphologies, and dynamics.

The atmospheric super-rotation at the upper clouds of Venus. While the super-rotation is present in both day and night sides of Venus, it seems more uniform in the day. Credits: JAXA, ESA, J. Peralta and R. Hueso.

Whereas plenty of studies have been conducted of Venus’ atmosphere from soace, this was the first time that a study was not focused on the dayside of the planet. As Dr. Peralta explained in an ESA press statement:

“This is the first time we’ve been able to characterize how the atmosphere circulates on the night side of Venus on a global scale. While the atmospheric circulation on the planet’s dayside has been extensively explored, there was still much to discover about the night side. We found that the cloud patterns there are different to those on the dayside, and influenced by Venus’ topography.“

Since the 1960s, astronomers have been aware that Venus’ atmosphere behaves much differently that those of other terrestrial planets. Whereas Earth and Mars have atmospheres that co-rotate at approximately the same speed as the planet, Venus’ atmosphere can reach speeds of more than 360 km/h (224 mph). So while the planet takes 243 days to rotate once on its axis, the atmosphere takes only 4 days.

This phenomena, known as “super-rotation”, essentially means that the atmosphere moves over 60 times faster than the planet itself. In addition, measurements in the past have shown that the fastest clouds are located at the upper cloud level, 65 to 72 km (40 to 45 mi) above the surface. Despite decades of study, atmospheric models have been unable to reproduce super-rotation, which indicated that some of the mechanics were unknown.

Artist’s impression of the atmosphere of Venus, showing its lightning storms and a volcano in the distance. Credit and ©: European Space Agency/J. Whatmore

As such, Peralta and his international team – which included researchers from the Universidad del País Vasco in Spain, the University of Tokyo, the Kyoto Sangyo University, the Center for Astronomy and Astrophysics (ZAA) at Berlin Technical University, and the Institute of Astrophysics and Space Planetology in Rome – chose to look at the unexplored side to see what they could find. As he described it:

“We focused on the night side because it had been poorly explored; we can see the upper clouds on the planet’s night side via their thermal emission, but it’s been difficult to observe them properly because the contrast in our infrared images was too low to pick up enough detail.”

This consisted of observing Venus’ night side clouds with the probe’s Visible and Infrared Thermal Imaging Spectrometer (VIRTIS). The instrument gathered hundreds of images simultaneously and different wavelengths, which the team then combined to improve the visibility of the clouds. This allowed the team to see them properly for the first time, and also revealed some unexpected things about Venus’ night side atmosphere.

What they saw was that atmospheric rotation appeared to be more chaotic on the night side than what has been observed in the past on the dayside. The upper clouds also formed different shapes and morphologies – i.e. large, wavy, patchy, irregular and filament-like patterns  – and were dominated by stationary waves, where two waves moving in opposite directions cancel each other out and create a static weather pattern.

Examples of new types of cloud morphology discovered on the night side of Venus thanks to Venus Express (ESA) and the infrared telescope IRTF (NASA). Credits: ESA/NASA/J. Peralta and R. Hueso.

The 3D properties of these stationary waves were also obtained by combining VIRTIS data with radio-science data from the Venus Radio Science experiment (VeRa). Naturally, the team was surprised to find these kinds of atmospheric behaviors since they were inconsistent with what has been routinely observed on the dayside. Moreover, they contradict the best models for explaining the dynamics of Venus’ atmosphere.

Known as Global Circulation Models (GCMs), these models predict that on Venus, super-rotation would occur in much the same way on both the dayside and the night side. What’s more, they noticed that stationary waves on the night side appeared to coincide with high-elevation features. As Agustin Sánchez-Lavega, a researcher from the University del País Vasco and a co-author on the paper, explained:

“Stationary waves are probably what we’d call gravity waves–in other words, rising waves generated lower in Venus’ atmosphere that appear not to move with the planet’s rotation. These waves are concentrated over steep, mountainous areas of Venus; this suggests that the planet’s topography is affecting what happens way up above in the clouds.“

This is not the first time that scientists have spotted a possible link between Venus’ topography and its atmospheric motion. Last year, a team of European astronomers produced a study that showed how weather patterns and rising waves on the dayside appeared to be directly connected to topographical features. These findings were based on UV images taken by the Venus Monitoring Camera (VMC) on board the Venus Express.

Schematic illustration of the proposed behaviour of gravity waves in the vicinity of mountainous terrain on Venus. Credit: ESA

Finding something similar happening on the night side was something of a surprise, until they realized they weren’t the only ones to spot them. As Peralta indicated:

“It was an exciting moment when we realized that some of the cloud features in the VIRTIS images didn’t move along with the atmosphere. We had a long debate about whether the results were real–until we realised that another team, led by co-author Dr. Kouyama, had also independently discovered stationary clouds on the night side using NASA’s Infrared Telescope Facility (IRTF) in Hawaii! Our findings were confirmed when JAXA’s Akatsuki spacecraft was inserted into orbit around Venus and immediately spotted the biggest stationary wave ever observed in the Solar System on Venus’ dayside.“

These findings also challenge existing models of stationary waves, which are expected to form from the interaction of surface wind and high-elevation surface features. However, previous measurements conducted by the Soviet-era Venera landers have indicated that surface winds might too weak for this to happen on Venus. In addition, the southern hemisphere, which the team observed for their study, is quite low in elevation.

And as Ricardo Hueso of the University of the Basque Country (and a co-author on the paper) indicated, they did not detect corresponding stationary waves in the lower cloud levels. “We expected to find these waves in the lower levels because we see them in the upper levels, and we thought that they rose up through the cloud from the surface,” he said. “It’s an unexpected result for sure, and we’ll all need to revisit our models of Venus to explore its meaning.”

Artist’s impression of Venus Express performing aerobreaking maneuvers in the planet’s atmosphere in June and July 2014. Credit: ESA–C. Carreau

From this information, it seems that topography and elevation are linked when it comes to Venus’ atmospheric behavior, but not consistently. So the standing waves observed on Venus’ night side may be the result of some other undetected mechanism at work. Alas, it seems that Venus’ atmosphere – in particular, the key aspect of super-rotation – still has some mysteries for us.

The study also demonstrated the effectiveness of combining data from multiple sources to get a more detailed picture of a planet’s dynamics. With further improvements in instrumentation and data-sharing (and perhaps another mission or two to the surface) we can expect to get a clearer picture of what is powering Venus’ atmospheric dynamics before long.

With a little luck, there may yet come a day when we can model the atmosphere of Venus and predict its weather patterns as accurately as we do those of Earth.

Further Reading: ESA, Nature Astronomy

Posted on by Matt Williams

Study of Martian Sedimentary Layers Reveals More About the Planet’s Past

An artist’s impression of what Mars might have looked like with water. Credit: ESO/M. Kornmesser

As of 2016, Mars became the permanent residence of no less than eight robotic missions, a combination of orbiters, rovers and landers. Between extensive studies of the Martian atmosphere and surface, scientists have learned a great deal about the planet’s history and evolution. In particular, they have uncovered voluminous amounts of evidence that Mars once had flowing water on its surface.

The most recent evidence to this effect from the University of Texas at Austin, where researchers have produced a study detailing how water deposited sediment in Mars’ Aeolis Dorsa region. According to their research, this area contains extensive sedimentary deposits that act as a historical record of Mars, cataloguing the influence played by water-based erosion over time.

The study, titled “Fluvial Stratigraphy of Valley Fills at Aeolis Dorsa, Mars: Evidence for Base-Level Fluctuations Controlled by a Downstream Water Body“, recently appeared in the scientific journal GeoScienceWorld. Led by Benjamin D. Cardenas – a geologist with the Jackson School of Geosciences at the University of Texas at Austin – the team examined satellite data of the Aeolis Dorsa region to study the structure of sedimentary deposits.

MOLA Topographic Map of Aeolis Quadrangle (MC-23) on the planet Mars. Credit: USGS

For years, Aeolis Dorsa has been of interest to scientists since it contains some of the most densely-packed sedimentary layers on Mars, which were deposited by flowing water (aka. fluvial deposits). These deposits are visible from orbit because of the way they have undergone a process known as “topographic inversion” – which consists of deposits filling low river channels, then being exhumed to create incised valleys.

By definition, incised valleys are topographic lows produced by “riverine” erosion – i.e. relating to a river or riverbank. On Earth, these valleys are commonly created by rising sea levels, and then filled with sediment as a result of falling sea levels. As sea levels rise, the valleys are cut from the landscape as the waters move inland; and as the sea levels drop, retreating waters deposit sediment within them.

According to the study, this process has created an opportunity for geophysicists and planetary scientist to observe Mars’ geological record in three dimensions and across significant distances. As Cardenas told Universe Today via email:

“Sedimentary rocks in general record information about the environments under which they were deposited. Fluvial (river) deposits specifically record information about the way rivers migrated laterally, the way they aggraded vertically, and how these things changed over time.”
The dotted white arrow points to curved strata recording point bar growth and river migration while the black arrow shows topographically inverted river deposits outcropping as ridges (e.g., black arrow). Credit: hou.usra.edu

Here on Earth, the statigraphy (i.e. the order and position of sedimentary layers) of sedimentary rocks has been used by geologists for generations to place constraints on what conditions were like on our planet billions of years ago. It has only been in recent history that the study of sedimentary layers has been used to place constraints on what environmental conditions were like on other planetary bodies (like Mars) billions of years ago.

However, most of these studies have produced data that has been unable to resolve sedimentary packaging at the sub-meter scale. Instead, satellite images have been used to define large-scale stratigraphic relationships, such as deposition patterns along past water channels. In other words, the studies have focused on cataloging the existence of past water flows on Mars more than what has happened since then.

As Cardenas indicated, he and his team took a different approach, one which considered that Mars has experienced changes over the past 3.5 billion years. As he explained:

“In general, there has been the assumption that a lot of the martian surface is not particularly different than it was 3.5 billion years ago. We make an effort to demonstrate that the modern surface at our study area, Aeolis Dorsa, is the result of burial, exhumation, and un-equal erosion, and it can’t be assumed that the modern surface represents the ancient surface at all. We really try to show that what we see today, the features we can measure today, are sedimentary deposits of rivers, and not actual rivers. This is incredibly important to realize when you start making interpretations of your observations, and it is frequently a missed point.”
Perspective view of Reull Vallis based on images taken by the ESA’s Mars Express. Reull Vallis, a river-like structure, is believed to have formed when running water flowed in the distant martian past. Credit and Copyright: ESA/DLR/FU Berlin (G. Neukum)

For the sake of their research, Cardenas and his team used stereo pairs of high-resolution images and topographic data taken by the Context Camera (CTX) and the High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO). This data was then combined with the Integrated Software for Imagers and Spectrometers (ISIS) –  a digital image-processing package used by the U.S. Geological Survey (USGS) – and NASA’s Ames Stereo Pipeline.

These processed the paired images into high-resolution topographic data and digital elevation models (DEMs) which were then compared to data from the Mars Orbiting Laser Altimeter (MOLA) instrument aboard the Mars Global Surveyor (MSG). The final result was a series of DEMs that were orders of magnitude higher in terms of resolution than anything previously produced.

For all of this, Cardenas and his colleagues were able to identify stacking patterns in the fluvial deposits, noted changes in sedimentation styles, and suggested mechanisms for their creation. In addition, the team introduced a brand new method to measure the flow direction of the rivers that left these deposits, which allowed them to see how the landscape has changed over the past few billion years.

“The study shows there was a large body of water on Mars ~3.5 billion years ago, and that this body of water increased and decreased in volume slowly enough that river sedimentation had time to adjust styles,” said Cardenas. “This is more in line with slower climatic changes, and less in line with catastrophic hydrologic events. Aeolis Dorsa is positioned along hypothesized coastlines of an ancient northern ocean on Mars. It’s interesting to find coastal river deposits at Aeolis Dorsa, but it doesn’t help us constrain the size of the water body (lake, ocean, etc.)”

Nanedi Valles, a roughly 800-kilometre valley believed to be caused by ground-water outflow. Copyright ESA/DLR/FU Berlin (G. Neukum)

In essence, Cardenas and his colleagues concluded that – similar to Earth – falling and rising water levels in a large water body forced the formation of the paleo-valleys in their study area. And in a way that is similar to what is happening on Earth today, rivers that formed in coastal regions were strongly influenced by changes in water levels of a large, downstream water body.

For some time, it has been something of a foregone conclusion that the surface of Mars is dead, its features frozen in time. But as this study demonstrated, the landscape has undergone significant changes since it lost its atmosphere and surface water. These findings will no doubt be the subject of interest as we get closer to mounting a crewed mission to the Martian surface.

Further Reading: GSA, GeoScienceWorld

Posted on by Ken Kremer

SpaceX Dragon Splashes Down in Pacific with 2 Tons of NASA Space Station Science

The SpaceX Dragon (far right) begins its departure from the International Space Station after being released from the grips of the Canadarm2 robotic arm on Sept. 17, 2017. Credit: NASA TV
The SpaceX Dragon (far right) begins its departure from the International Space Station after being released from the grips of the Canadarm2 robotic arm on Sept. 17, 2017. Credit: NASA TV

KENNEDY SPACE CENTER, FL – Concluding a month long stay at the International Space Station (ISS) a SpaceX Dragon cargo freighter loaded with some two tons of NASA research samples, hardware and micestonauts returned home to make a successful splashdown in the Pacific on Sunday, Sept. 17.

The SpaceX Dragon CRS-12 resupply ship successfully splashed down in the Pacific Ocean at approximately 10:14 a.m. EDT, 7:14 a.m. PDT, 1414 GMT Sunday, southwest of Long Beach, California, under a trio of main parachutes.

The parachute assisted splashdown marked the end of the company’s twelfth contracted cargo resupply mission to the orbiting outpost for NASA.

The capsule returned with more than 3,800 pounds (1,700 kg) of cargo and research and 20 live mice.

“Good splashdown of Dragon confirmed, completing its 12th mission to and from the @Space_Station,” SpaceX confirmed via twitter.

The SpaceX Dragon CRS-12 spacecraft begins its departure from the International Space Station after being released from the grips of the Canadarm2 robotic arm on Sept. 17, 2017. Credit: NASA TV

Liftoff of the SpaceX Falcon 9 carrying Dragon CRS-12 to orbit took place from seaside pad 39A at NASA’s Kennedy Space Center in Florida on Aug. 14 at 12:31 p.m. EDT (1631 GMT).

After a two day orbital chase Dragon had been berthed at the station since arriving on Aug. 16.

SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com

Dragon’s departure began early Sunday morning when Expedition 53 Flight Engineer Paolo Nespoli of ESA (European Space Agency) and ISS Commander Randy Bresnik of NASA released the Dragon spacecraft from the grips of the Canadarm2 robotic arm at 4:40 a.m. EDT, 1:40 a.m. PDT, 840 GMT.

The departure events were carried live on NASA TV. There was no live broadcast of the Pacific Ocean landing.

Working from a robotics work station inside the seven windowed domed Cupola module Nespoli and Bresnik used the station’s 57.7-foot-long (17.6 meter-long) Canadian-built robotic arm to detach Dragon from the Earth-facing port of the Harmony module and release it into space.

“We would like to give a big thanks to all the operational teams around the world that keep our presence in space possible – to the scientists and engineers that provide the outstanding research and equipment that we have in space, to NASA and all the space agencies that contribute to the space station. And to SpaceX for giving us this outstanding vehicle,” Nespoli radioed.

Dragon then backed away slowly via a trio of thruster firings.

“The three departure burns to move Dragon away from the @Space_Station are complete,” SpaceX confirmed.

The departure of the SpaceX Dragon Sunday morning, Sept. 17, 2017 leaves three spaceships parked at the space station including the Progress 67 resupply ship and the Soyuz MS-05 and MS-06 crew ships. Credit: NASA

The final de-orbit burn took place as planned around 9 a.m. EDT some four and a half hours after leaving the station and setting Dragon up for the scorching reentry into the Earth’s atmosphere.

“Dragon’s de-orbit burn is complete and trunk has been jettisoned. Pacific Ocean splashdown in ~30 minutes,” said SpaceX.

All the drogue and main parachutes deployed as planned during the descent to Earth.

“Dragon’s three main parachutes have been deployed.”

SpaceX commercial naval ships were on standby to retrieve the spacecraft from the ocean and sail it back to port in Long Beach, California.

Some time critical research specimens will be removed immediately for return to NASA. The remainder will be transported back with Dragon to SpaceX’s test facility in McGregor, Texas, for final post flight processing and handover to NASA.

“A variety of technological and biological studies are returning in Dragon. NASA and the Center for the Advancement of Science in Space (CASIS), the non-profit organization that manages research aboard the U.S. national laboratory portion of the space station, will receive time-sensitive samples and begin working with researchers to process and distribute them within 48 hours,” said NASA in a statement.

The Dragon resupply ship dubbed Dragon CRS-12 counts as SpaceX’s twelfth contracted commercial resupply services (CRS) mission to the International Space Station for NASA since 2012.

SpaceX holds a NASA commercial resupply services (CRS) contract that includes up to 20 missions under the original CRS-1 contract.

The 20-foot high, 12-foot-diameter Dragon CRS-12 vessel carried more than 6,400 pounds ( 2,900 kg) of science experiments and research instruments, crew supplies, food water, clothing, hardware, gear and spare parts to the million pound orbiting laboratory complex when it launched Aug. 14 from KSC pad 39A.

20 mice were also onboard and were returned alive on the round trip flight.

This mission supported dozens of the 250 research investigations and experiments being conducted by Expedition 52 and 53 crew members – including NASA’s space endurance record breaking astronaut Peggy Whitson.

The Cosmic-Ray Energetics and Mass investigation (CREAM) instrument from the University of Maryland, College Park involves placing a balloon-borne instrument aboard the International Space Station to measure the charges of cosmic rays over a period of three years. CREAM will be attached to the Japanese Experiment Module Exposed Facility. Existing CREAM hardware used for balloon flights. Credit: NASA

Whitson returned to Earth in a Soyuz capsule earlier this month following a 10 month mission and carried out research included in the samples returned by Dragon CRS-12.

Visiting vehicle configuration at the International Space Station (ISS) after arrival of the Soyuz MS-06 spacecraft on Sept. 12, 2017. Credit: NASA

Here’s a NASA science summary:

The Lung Tissue experiment used the microgravity environment of space to test strategies for growing new lung tissue. The ultimate goal of this investigation is to produce bioengineered human lung tissue that can be used as a predictive model of human responses allowing for the study of lung development, lung physiology or disease pathology.

Samples from the CASIS PCG 7 study used the orbiting laboratory’s microgravity environment to grow larger versions of an important protein implicated in Parkinson’s disease. Developed by the Michael J. Fox Foundation, Anatrace and Com-Pac International, researchers will look to take advantage of the station’s microgravity environment which allows protein crystals to grow larger and in more perfect shapes than earth-grown crystals, allowing them to be better analyzed on Earth. Defining the exact shape and morphology of LRRK2 would help scientists to better understand the pathology of Parkinson’s and aid in the development of therapies against this target.

Mice from NASA’s Rodent Research-9 study also will return live to Earth for additional study. The investigation combined three studies into one mission, with two looking at how microgravity affects blood vessels in the brain and in the eyes and the third looking at cartilage loss in hip and knee joints. For humans on Earth, research related to limited mobility and degrading joints can help scientists understand how arthritis develops, and a better understanding of the visual impairments experienced by astronauts can help identify causes and treatments for eye disorders.

The next SpaceX Dragon is due to blastoff around December from KSC.

An Orbital ATK Cygnus cargo ship is slated to launch in November from NASA Wallops in Virginia.

Watch for Ken’s continuing onsite NASA 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.

Ken Kremer

Ground landing of SpaceX Falcon 9 first stage at Landing Zone-1 (LZ-1) after SpaceX launched its 12th resupply mission to the International Space Station from NASA’s Kennedy Space Center in Florida from pad 39A at 12:31 p.m. EDT on Monday, Aug. 14, 2017. Credit: Ken Kremer/Kenkremer.com
The Soyuz MS-06 rocket blasts off with the Expedition 53-54 crew towards the International Space Station from the Baikonur Cosmodrome in Kazakhstan, Tuesday, Sept. 12, 2017 (Wednesday, Sept. 13, Kazakh time). Credit: NASA/Bill Ingalls
Posted on by Matt Williams

New Study Indicates that Planet 9 Likely Formed in the Solar System

Artist's impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign
Artist's impression of Planet Nine, blocking out the Milky Way. The Sun is in the distance, with the orbit of Neptune shown as a ring. Credit: ESO/Tomruen/nagualdesign

In January of 2016, astronomers Mike Brown and Konstantin Batygin published the first evidence that there might be another planet in our Solar System. Known as “Planet 9”, this hypothetical body was believed to orbit at an extreme distance from our Sun. Since that time, multiple studies have been produced that have had tried to address the all-important question of where Planet 9 could have come from.

Whereas some studies have suggested that the planet moved to the edge of the Solar System after forming closer to the Sun, others have suggested that it might be an exoplanet that was captured early in the Solar System’s history. A recent study by a team of astronomers has cast doubt on this latter possibility, however, and indicates that Planet 9 likely formed closer to the Sun and migrated outward during its history.

Their study, titled “Was Planet 9 Captured in the Sun’s Natal Star-Forming Region?“, recently appeared in the Monthly Notices of the Royal Astronomical Society. The team was led by Dr. Richard Parker from the University of Sheffield’s Department of Physics and Astronomy, with colleagues from ETH Zurich. Together, they conducted simulations that cast doubt on the “capture” scenario.

The six most distant known objects in the solar system with orbits exclusively beyond Neptune (magenta) all mysteriously line up in a single direction. Credit: Caltech/R. Hurt (IPAC); [Diagram created using WorldWide Telescope.]
The existence of Planet 9 (or Planet X, for those who maintain that Pluto is still a planet) was first suggested in 2014 by astronomers Chad Trujillo and Scott S. Sheppard, based on the unusual behavior of certain populations of extreme Trans-Neptunian Objects (eTNOs). From a number of studies that took place over the next few years, constraints were gradually placed on the basic parameters of this planet.

Essentially, Planet 9 is believed to be at least ten times as massive as Earth and two to four times the size. It also believed to have a highly elliptical orbit around the Sun, at an average distance (semi-major axis) of approximately 700 AU and ranging from about 200 AU at perihelion to 1200 AU at aphelion. Last, but not least, scientists have estimated that Planet 9 takes between 10,000 and 20,000 years to complete a single orbit of the Sun.

Because of this, it appears unlikely that Planet 9 could have formed in its current location. Hence why astronomers have argued that it either formed closer to the Sun or was captured from another star system billions of years ago. As Dr. Parker explained in University of Sheffield press statement:

“We know that planetary systems form at the same time as stars, and when stars are very young they are usually found in groups where interactions between stellar siblings are common. Therefore, the environment where stars form directly affects planetary systems like our own, and is usually so densely populated that stars can capture other stars or planets.”

Animated diagram showing the spacing of the Solar Systems planet’s, the unusually closely spaced orbits of six of the most distant KBOs, and the possible “Planet 9”. Credit: Caltech/nagualdesign

For the sake of their study, the team conducted simulations of the Solar System when it was still in its “nursery” phase – i.e. in the early process of formation. While interactions with other star systems (and their planets) are known to be common in this period, the team found that even where conditions were optimized for the sake of capturing free-floating planets, the odds of Planet 9 being captured were quite low.

Overall, their simulations indicated that with an orbit like that of Planet 9, only 5 to 10 planets out of 10,000 would be captured when the Solar System was still young. In short, the likelihood that Planet 9 could have been booted out of another star system and captured by our Sun was a paltry 1 out of a 1,000 to 2,000. Not exactly betting odds! As Dr. Parker summarized:

“In this work, we have shown that – although capture is common – ensnaring planets onto the postulated orbit of Planet 9 is very improbable. We’re not ruling out the idea of Planet 9, but instead we’re saying that it must have formed around the sun, rather than captured from another planetary system.”

If Planet 9 was not captured, then there remains only one possibility: ut formed closer to our Sun and gradually migrated beyond the orbit of Neptune, reaching distances occupied only by the most extreme Kuiper Belt Objects. And while the hunt of this elusive and mysterious planet is ongoing, any research which places additional constraints on its characteristics and origin are extremely useful.

By ruling out different scenarios in which the planet formed, researchers are also raising new questions about the history and evolution of our Solar System. From when did all the planets we know come from? Did they form in their current orbits, or did migration play a role? These and other questions are sure to be raised and addressed as we close in on Planet 9.

Further Reading: University of Sheffield, MNRAS

Posted on by Ken Kremer

KSC and Visitor Complex Reopen in Aftermath of Hurricane Irma; with Launches Delayed and Viewing Spots Destroyed: Gallery

Rotary Rover Front park along the Indian River lagoon in Titusville, FL which offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center was destroyed by Hurricane Irma on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com
Rotary Rover Front park along the Indian River lagoon in Titusville, FL which offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center Credit: Ken Kremer/kenkremer.com

TITUSVILLE/CAPE CANAVERAL, FL – NASA’s Kennedy Space Center, the KSC Visitor Complex and Cape Canaveral Air Force Station have reopened as of today (Sept. 16) and yesterday, respectively, in the aftermath of Cat 1 hurricane force winds from Hurricane Irma that lashed the Florida Space Coast on Saturday, Sunday and Monday (Sept. 9/10/11) – forcing launch delays and leaving damaged and destroyed homes, buildings, infrastructure and launch viewing locations in its wake – see photos.

Cape Canaveral Air Force Station military forces partially reopened certain critical runways hours after Irma swept by the space coast to assist in emergency recovery operations.

“Kennedy Space Center will resume normal operations Saturday, Sept. 16,” NASA announced. “The “All Clear” has been given to reopen.”

NASA’s world famous Vehicle Assembly Building and the Space Coast launch pads are still standing – as seen in photos from myself and more from NASA.

Launch Complex 39 and surrounding areas are seen during an aerial survey of NASA’s Kennedy Space Center in Florida on Sept. 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on Sept. 10, 2017. Credit: NASA KSC

“As you’ve all seen by now, the Center will be open for normal operations at midnight tonight, and we’ll be ready to get back into the full swing of things Monday morning,” KSC Center Director Bob Cabana said in a message to employees.

Hurricane Irma knocked out water and power to KSC, the Cape, the visitor complex and the barrier islands including Merritt Island which is home to America’s premier Spaceport.

Wind speeds at KSC “varied from 67-94 mph (59-82 knots) at the 54-foot level to 90-116 mph (79-101 knots) at the 458-foot level during the storm.”

As a direct result of Irma, the next Space Coast launches of a United Launch Alliance Atlas V and SpaceX Falcon 9 has been postponed into October.

“The storm did delay the next launches,” said Brig. Gen. Wayne R. Monteith, Commander, 45th Space Wing, at a media briefing.

“We think the next launch will be approximately the first week of October.”

However although there was damage to a numerous buildings, both the spacecraft and rockets are safe and sound.

“The spacecraft we have on station right now are healthy and are being monitored.”

“The seven rocket boosters [Atlas, Falcon, Delta IV Heavy] we have on the Cape rode out the storm just fine,” Montieth elaborated.

The base and the visitor complex both lacked potable water service used for drinking, food preparation and cleaning.

Multiple water pipes in the nearby community of Cocoa were severed. KSC, the Cape and the Visitor Center as well as the surrounding community were under a boil water restriction for several days.

“Full water service is now available and the center has received an all clear following several days of closure related to Hurricane Irma,” noted KSC officials.

Space View park along the Indian River lagoon in Titusville, FL which offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center was destroyed by Hurricane Irma on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com

Indeed over 87% of customers lost power in Brevard County – home to the Florida Space Coast. Over 2/3 of customers lost power throughout Florida- impacting over 16 million people.

A number of popular public launch viewing locations were also severely damaged or destroyed as I witnessed personally driving in Titusville around just hours after Irma fled north.

See my photos from Rotary River Front Park, Space View Park and others along Rt. 1 in Titusville – which had offered unimpeded, spectacular and beautiful views across the Indian Rover lagoon to the KSC and Cape Canaveral launch pads.

Space View park along the Indian River lagoon in Titusville, FL offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center until the piers and walkways were decimated by Hurricane Irma on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com

Piers, docks, walkways, parking areas, piping and more were ripped up, smashed, sunken and devastated with piles of metal, bricks, wood, trees, bushes, trash and more scattered about in sad and unrecognizable heaps.

Space View park along the Indian River lagoon in Titusville, FL offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center until the piers and walkway were decimated by Hurricane Irma on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com

From a distance of several miles, the iconic VAB and the launch pads themselves did not seem to suffer obvious destruction – see my photos herein.

As of today over 500,000 customers across Florida remain without power, including tens of thousands in central Florida.

Numerous traffic lights in Titusville, Cape Canaveral, Cocoa Beach and Melbourne and other Brevard County and central Florida cities and communities are still not functioning today – creating all sorts of road traffic hazards!

Rotary Rover Front park along the Indian River lagoon in Titusville, FL was devastated by Hurricane Irma on Sept. 10/11, 2017. The serene coastal park had offered magnificent views of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center. Credit: Ken Kremer/kenkremer.com

Damage assessment teams from NASA, ULA, SpaceX, the USAF and contractors are now carefully scrutinizing every aspect of the Space Coast launch pads and facilities to ensure successful liftoffs whenever they resume in a few weeks.

Virtually all traffic lights were not operating and businesses and gas stations were closed in the hours before and after Irma pummeled communities across the space coast and central Florida. There were very long lines at the first gas stations that did reopen on Monday and Tuesday.

NASA’s iconic Vehicle Assembly Building (VAB) and the Launch Control Center (left) were home to the ‘ride-out’ crew remaining on site at the Kennedy Space Center, FL during Hurricane Irma to monitor facilities as the storm passed by on Sept. 10/11. They survived intact in this post storm view taken from Playalinda Beach. Credit: Ken Kremer/kenkremer.com

KSC was closed and evacuated of all personnel during the storm, except for only a small ‘Ride-out’ team of roughly 130 or so KSC personnel based inside the Emergency Operations Center (EOC) inside the Launch Control Center. They remained on site to monitor spaceport facilities.

“I want to take this opportunity to thank—and commend—the Ride-out and Damage Assessment and Recovery Teams for the outstanding job they did watching over the Center in our absence and getting it ready for our return in the aftermath of Hurricane Irma,” Cabana added. “I also want to thank all of you for the outstanding job that you did in getting the Center ready for the hurricane. As a result of your efforts, the Center was well prepared for the storm.”

The Damage Assessment and Recovery Teams explained that “the industrial and Launch Complex 39 areas have been inspected and are safe for personnel to return to work. This includes the KSC Child Development Center and all administrative work areas.”

Huge slabs of coastal concrete walkway buckled and collapsed on Route 1 along the Indian River lagoon in Titusville, FL that was a popular spot offering outstanding public launch viewing – decimated as Hurricane Irma passed by on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com

“All facility systems including communication, power, and air conditioning are functional.”

Montieth confirmed damage to many buildings.

“In an initial assessment of the Cape facilities, about 40 % of buildings we inspected so far have received some damage. So 107 of 216 buildings at the Cape inspected have already been identified with damage.

Launch Complex 39 and surrounding areas are seen during an aerial survey of NASA’s Kennedy Space Center in Florida on Sept. 12, 2017. The survey was performed to identify structures and facilities that may have sustained damage from Hurricane Irma as the storm passed Kennedy on Sept. 10, 2017. KSC reopens on Sept. 10, 2017. Credit: NASA KSC

“Lots of roof and siding damage, Montieth explained on Sept. 13. “We haven’t inspected the beaches yet.

“We have water issues at the Cape. We need water for the chillers to cool the operational buildings.”
Luckily the damage from Irma was less than feared.

“Under Hurricane Matthew there was about $50 million worth of damage between us and our launch partners. We think it will be less this time for Irma but we have a lot more work to do,” noted Montieth.

“The storm wasn’t as bad as expected. You hope for the best and prepare for the worst and that’s what we did. We had a ride-out team on base in a secure facility. Irma traveling over land helped us out. But we still got hit here by over 90 MPH winds gusts and over 58 mph winds – which are hurricane category 1 winds.”

“We also got hit by what we believe are 3 probable small tornadoes that hit the base. That claim is up to the NWS.”

He noted that the X-37B was launched successfully last Friday by SpaceX and that ongoing hurricane preparations and evacuations went to full swing right afterward the morning blastoff.

USAF X-37B military spaceplane blasts off with picturesque water reflections at 10 a.m. EDT (1400 UTC) Sept. 7, 2017 on a SpaceX Falcon 9 rocket from Launch Complex 39A at the Kennedy Space Center. Credit: Ken Kremer/kenkremer.com

Watch for Ken’s continuing onsite X-37B OTV-5 and NASA 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.

Ken Kremer

Derelict boat crashed up on shore along the Indian River lagoon in Titusville, FL right after Hurricane Irma pounded the Space Coast on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com
Thrashing waves and winds from Hurricane Irma nearly washed away the roadway past the Max Brewer Bridge, Titusville leading to Playalinda Beach on Sept. 10/11, 2017. Water levels were several feet above normal hours after the storm passed. Credit: Ken Kremer/kenkremer.com
Rotary Rover Front park along the Indian River lagoon in Titusville, FL which offered a magnificent view of the iconic Vehicle Assembly Building and launches from Launch Complex 39A on NASA’s Kennedy Space Center was destroyed by Hurricane Irma on Sept. 10/11, 2017. Credit: Ken Kremer/kenkremer.com
Launch Complex 39A and SpaceX processing hangar at NASA’s Kennedy Space Center survived intact after Hurricane Irma swept by on Sept. 10/11, 2017 in this post storm view taken from Playalinda Beach. Credit: Ken Kremer/kenkremer.com
Launch Complex 39B at NASA’s Kennedy Space Center survived intact after Hurricane Irma swept by on Sept. 10/11, 2017 in this post storm view taken from Playalinda Beach. Credit: Ken Kremer/kenkremer.com
Posted on by Matt Williams

Hubble Spots Pitch Black Hot Jupiter that “Eats Light”

Illustration showing one of the darkest known exoplanets - an alien world as black as fresh asphalt - orbiting a star like our Sun. The day side of the planet, called WASP-12b, eats light rather than reflects it into space. Credit: NASA, ESA, and G. Bacon (STScI)

The study of extra-solar planets has revealed discoveries that have confounded expectations and boggled the mind! Whether it’s Super-Earths that become diamond planets, multiple rocky planets orbiting closely together, or “Hot Jupiters” with traces of gaseous metal in their atmospheres, there’s been no shortage of planets out there for which there is no comparison here in the Solar System.

In this respect, WASP-12b is in good company. This Hot-Jupiter, located in a star system 1400 light years from Earth in the direction of the Auriga constellation, was recently studied by a team of astronomers using the Hubble Space Telescope. Due to the particular nature of its atmosphere, which absorbs the vast majority of light it receives instead of reflecting it, this planet appeared pitch black when observed by the Hubble team.

The study which details their findings, “The Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubble“, was recently published in The Astrophysical Journal. Led by Taylor Bell, a researcher at the Institute for Research on Exoplanets (IREx) at McGill University, the team consulted data from the Hubble’s Space Telescope Imaging Spectrograph (STIS) to observe WASP-12b during an optical eclipse.

WASP-12b orbits so close to its star that it is heated to a record-breaking 2500°C. Credit: ESA/C Carreau

Like all Hot Jupiters, WASP-12b is similar in mass to Jupiter (1.35 to 1.43 Jupiter masses) and orbits very close to its star. At a distance of just 3.4 million km (2.115 million mi), or 0.0229 AU, it takes a little over a day to complete a single orbit. Because of its proximity, one side of the planet is constantly facing towards it’s sun – i.e. it is tidally locked with its star.

Because of its orbit, temperatures on the day side of the planet are estimated to reach as high as 2811 K (2538 °C; 4600 °F). It is because of these extreme temperatures that most molecules are unable to survive on the day side of the planet, so clouds cannot form to reflect light back into space. As a result, most incoming light penetrates deep into the planet’s atmosphere, where it is absorbed by hydrogen atoms and converted into heat energy.

This was what Bell and his team noticed as they observed the planet passing behind its star (aka. an optical eclipse). Using the STIS, they monitored the system for any dips in starlight, which would indicate how much reflected light was being given off by the planet. However, their observations did not detect reflected light, which indicated that the sun-facing side was absorbing most of the light it was receiving.

As Bell explained in a NASA press statement, this was quite the unusual find: “We did not expect to find such a dark exoplanet,” he said. “Most hot Jupiters reflect about 40 percent of starlight.” However, observations conducted of the night side of the planet show that things are quite different there. On this side, temperatures are about 1366 K (1093 °C; 2000 °F) cooler, which allows water vapor and clouds to form.

An artist’s impression of WASP 12-b being slowly consumed as a result of its ridiculously tight orbit around its star. Credit: NASA.

Back in 2013, scientists working with the HST detected traces of water vapor in the atmosphere (and possible traces of clouds as well) while studying the day/night boundary. As Bell indicated, this new research just goes to show just how diverse this type of gas giant can be:

“This new Hubble research further demonstrates the vast diversity among the strange population of hot Jupiters. You can have planets like WASP-12b that are 4,600 degrees Fahrenheit and some that are 2,200 degrees Fahrenheit, and they’re both called hot Jupiters. Past observations of hot Jupiters indicate that the temperature difference between the day and night sides of the planet increases with hotter day sides. This previous research suggests that more heat is being pumped into the day side of the planet, but the processes, such as winds, that carry the heat to the night side of the planet don’t keep up the pace.”

Since its discovery in 2008, several telescopes have studied WASP-12b, including Hubble, NASA’s Spitzer Space Telescope, and NASA’s Chandra X-ray Observatory. Previous observations by Hubble’s Cosmic Origins Spectrograph (COS) also revealed that the planet may be losing size and mass due to super-heated material from its atmosphere slowly being accreted onto the star.

This is just the latest find in a slew that has confounded scientists expectations about exoplanets. The more we come to learn about the nature and diversity of these distant worlds, the more tantalizing they seem and the more appealing the prospect of exploring them directly someday becomes!

Further Reading: NASA, IREx, Astrophysical Journal Letters

Posted on by Nancy Atkinson

Loss of Signal: Cassini Spacecraft Plunges Into Saturn

Artist concept of Cassini's last moments at Saturn. Credit: NASA/JPL.

Until the very end, Cassini displayed just how robust and enduring this spacecraft has been throughout its entire 20 years in space and its 13-year mission at Saturn. As Cassini plummeted through the ringed-planet’s atmosphere, its thrusters fought the good fight to keep the antenna pointed at Earth for as long as possible, sending as much of the last drops of science data as it could.

Cassini endured about 40 seconds longer than expected before loss of signal was called at 11:55:46 UTC

“I hope you’re all deeply proud of this accomplishment,” said Cassini Project Manager Earl Maize in JPL’s Mission Control Center after Cassini’s signal was lost. “This has been an incredible mission, and incredible spacecraft and an incredible team. I’m going to call this the end of mission. Project Manager off the net.”

Of course, the actual demise of Cassini took place about an hour and 23 minutes before, as it took that long for the signal to travel the 1.5 billion km distance from Saturn to Earth.

“This is a bittersweet moment for all of us,” said JPL Director Mike Watkins, “but I think it is more sweet than bitter because Cassini has been such an incredible mission. This is a great time to celebrate the hard work and dedication of those who have worked on this mission.”

Watkins added that almost everything we know about Saturn comes from the Cassini mission. “It made discoveries so compelling that we have to back,” he said. “We will go back and fly through the geysers of Encleadus and we’ll go back to explore Titan… These are incredibly compelling targets.”

Cassini program manager at JPL, Earl Maize, left, and spacecraft operations team manager for the Cassini mission at Saturn, Julie Webster, right, embrace after the Cassini spacecraft plunged into Saturn, Friday, Sept. 15, 2017 at NASA’s Jet Propulsion Laboratory in Pasadena, California. Photo Credit: (NASA/Joel Kowsky)

Cassini launched on Oct. 15, 1997, and arrived at Saturn’s in 2004. It studied Saturn’s rings and sent back postcards almost every day of its journeys around the Saturn system, pictures of complex moons, the intriguing rings and the giant gas planet.

It revealed the moon Enceladus as one of the most geothermally active places in our solar system, showing it to be one of the prime targets in the search for life beyond Earth.

Saturn’s active, ocean-bearing moon Enceladus sinks behind the giant planet in a farewell portrait from NASA’s Cassini spacecraft.
Credits: NASA/JPL-Caltech/Space Science Institute

Also, piggybacking along was the Huygens probe to study Saturn’s largest moon, Titan. This landing in 2005 was the first spacecraft to land in the outer solar system.

During its final plunge, Cassini’s instruments captured data on Saturn’s atmosphere, sending a strong signal throughout. As planned, data from eight of Cassini’s science instruments will be providing new insights about Saturn, including hints about the planet’s formation and evolution, and processes occurring in its atmosphere.

This death plunge ensures Saturn’s moons will remain pristine for future exploration.

Over 260 scientists from 17 countries and hundreds of engineers worked with Cassini throughout the entire mission. During Cassini’s final days, mission team members from all around the world gathered at JPL to celebrate the achievements of this historic mission.

Here is the last picture taken by Cassini’s cameras, showing the place where Cassini likely met its demise:

This monochrome view is the last image taken by the imaging cameras on NASA’s Cassini spacecraft. It looks toward the planet’s night side, lit by reflected light from the rings, and shows the location at which the spacecraft would enter the planet’s atmosphere hours later. Credit: NASA/JPL-Caltech/Space Science Institute

If you can’t get enough of Cassini, there will be more information coming about this final data, and of course, you can go look at all the images it has sent back here. Also, NASA has provided an ebook for download that includes information and images from the mission.

Posted on by Matt Williams

Astronomers Spot Hellish World with Titanium in its Atmosphere

Artist's impression showing the exoplanet WASP-19b, in which atmosphere astronomers detected titanium oxide for the first time. Credit: ESO

The hunt for exoplanets has turned up many fascinating case studies. For example, surveys have turned up many “Hot Jupiters”, gas giants that are similar in size to Jupiter but orbit very close to their suns. This particular type of exoplanet has been a source of interest to astronomers, mainly because their existence challenges conventional thinking about where gas giants can exist in a star system.

Hence why an international team led by researchers from the European Southern Observatory (ESO) used the Very Large Telescope (VLT) to get a better look at WASP-19b, a Hot Jupiter located 815 light-years from Earth. In the course of these observations, they noticed that the planet’s atmosphere contained traces of titanium oxide, making this the first time that this compound has been detected in the atmosphere of a gas giant.

The study which describes their findings, titled “Detection of titanium oxide in the atmosphere of a hot Jupiter“, recently appeared in the science journal Nature. Led by Elyar Sedaghati – a recent graduate from the Technical University of Berlin and a fellow at the European Southern Observatory – the team used data collected by the VLT array over the course of a year to study WASP-19b.

Like all Hot Jupiters, WASP-19b has about the same mass as Jupiter and orbits very close to its sun. In fact, its orbital period is so short  – just 19 hours – that temperatures in its atmosphere are estimated to reach as high as 2273 K (2000 °C; 3632 °F). That’s over four times as hot as Venus, where temperatures are hot enough to melt lead! In fact, temperatures on WASP-19b are hot enough to melt silicate minerals and platinum!

The study relied on the FOcal Reducer/low dispersion Spectrograph 2 (FORS2) instrument on the VLT, a multi-mode optical instrument capable of conducting imaging, spectroscopy and the study of polarized light (polarimetry). Using FORS2, the team observing the planet as it passed in front of its star (aka. made a transit), which revealed valuable spectra from its atmosphere.

After carefully analyzing the light that passed through its hazy clouds, the team was surprised to find trace amounts of titanium oxide (as well as sodium and water). As Elyar Sedaghati, who spent 2 years as a student with the ESO to work on this project, said of the discovery in an ES press release:

“Detecting such molecules is, however, no simple feat. Not only do we need data of exceptional quality, but we also need to perform a sophisticated analysis. We used an algorithm that explores many millions of spectra spanning a wide range of chemical compositions, temperatures, and cloud or haze properties in order to draw our conclusions.”

Titanium oxide is a very rare compound which is known to exist in the atmospheres of cool stars. In small quantities, it acts as a heat absorber, and is therefore likely to be partly responsible for WASP-19b experiencing such high temperatures. In large enough quantities, it can prevent heat from entering or escaping an atmosphere, causing what is known as thermal inversion.

This is a phenomena where temperatures are higher in the upper atmosphere and lower further down. On Earth, ozone plays a similar role, causing an inversion of temperatures in the stratosphere. But on gas giants, this is the opposite of what usually happens. Whereas Jupiter, Saturn, Uranus and Neptune experience colder temperatures in their upper atmospheres, temperatures are much hotter closer to the core due to increases in pressure.

The team believes that the presence of this compound could have a substantial effect on the atmosphere’s temperature, structure and circulation. What’s more, the fact that the team was able to detect this compound (a first for exoplanet researchers) is an indication of how exoplanet studies are achieving new levels of detail. All of this is likely to have a profound impact on future studies of exoplanet atmospheres.

The study would also have not been possible were it not for the FORS2 instrument, which was added to the VLT array in recent years. As Henri Boffin, the instrument scientist who led the refurbishment project, commented:

“This important discovery is the outcome of a refurbishment of the FORS2 instrument that was done exactly for this purpose. Since then, FORS2 has become the best instrument to perform this kind of study from the ground.”

Looking ahead, it is clear that the detection of metal oxides and other similar substances in exoplanet atmospheres will also allow for the creation of better atmospheric models. With these in hand, astronomers will be able to conduct far more detailed and accurate studies on exoplanet atmospheres, which will allow them to gauge with greater certainty whether or not any of them are habitable.

So while this latest planet has no chance of supporting life – you’d have better luck finding ice cubes in the Gobi desert! – its discovery could help point the way towards habitable exoplanets in the future. On step closer to finding a world that could support life, or possibly that elusive Earth 2.0!

Further Reading: ESO, Nature