River relic spied by Mars Express

ESA - Mars Express Mission patch.

10 October 2019

Mars may seem to be an alien world, but many of its features look eerily familiar – such as this ancient, dried-up river system that stretches out for nearly 700 kilometres across the surface, making it one of the longest valley networks on the planet.

Plan view of Nirgal Vallis

The area of Mars shown in these new images from ESA’s Mars Express spacecraft lies just south of the planet’s equator, and is known to have been shaped by a mix of flowing water and impacts: events where rocks sped inwards from space to collide with the martian surface.

Both of these mechanisms are visible here: a number of impact craters, some large and some small, can be seen speckled across the ochre, caramel-hued surface, and a tree-like, forked channel cuts prominently through the centre of the frame.

Nirgal Vallis in context

This ancient valley system is named Nirgal Vallis, and was once filled with running water that spread across Mars. By exploring the characteristics of the surrounding craters, scientists estimate the system’s age to be between 3.5 and 4 billion years old.

Topographic view of Nirgal Vallis

The part of Nirgal Vallis captured in these images lies towards the western end of the river system, where it is slowly spreading out and dissipating; the eastern end is far less branched and more clearly defined as a single valley, and opens out into the large Uzboi Vallis – the suspected location of a large, ancient lake that has long since dried up.

Nirgal Vallis is a typical example of a feature known as an amphitheatre-headed valley. As the name suggests, rather than ending bluntly or sharply, the ends of these tributaries have the characteristic semi-circular, rounded shape of an Ancient Greek amphitheatre. Such valleys also typically have steep walls, smooth floors, and, if sliced through at a cross-section, adopt a ‘U’ shape. The valleys pictured here are about 200 m deep and 2 km wide, and their floors are covered in sandy dunes; the appearance of these dunes indicates that martian winds tend to blow roughly parallel to the valley walls. 

Perspective view of Nirgal Vallis

We see valleys like this often on Earth, including valleys found in the Chilean Atacama Desert, the Colorado Plateau, and on the islands of Hawaii. Mars also hosts a few of them, with Nanedi Valles and Echus Chasma joining Nirgal Vallis as clear examples of this intriguing feature. Both of these features also resemble terrestrial drainage systems, where meandering, steep-sided valleys – thought to have been formed by free-flowing water – have carved their way through hundreds of kilometres of martian rock, forging through old volcanic plains, lava flows, and material deposited by strong martian winds over time.

Valleys such as Nirgal Vallis are ubiquitous in the low-latitude regions surrounding the martian equator, indicating that these areas once experienced a far milder and more Earth-like climate. Despite the arid, hostile world we see today, Mars is thought to have once been a far warmer and wetter planet – and we see signs of this in the diverse mix of features and minerals found across its surface.

Mars Express

Scientists believe that Nirgal Vallis formed in a similar way to morphologically similar valleys we see on Earth. As there appear to be no branching, tree-like tributaries feeding into the main valley of Nirgal Vallis, it is likely that water was replenished on ancient Mars by a mix of precipitation and overland flow from the surrounding terrain.

The system may also have its roots in a process known as groundwater sapping: when water struggles to travel vertically through a medium, and so instead continually seeps laterally through material in layers beneath the surface. We see this kind of mechanism on Earth in environments where surface material is very fine and loose and thus difficult for water to penetrate – largely silty, sandy, unconsolidated, and fine-grained environments, where lower layers of the surface are permeable and friendlier to water than those above.

Nirgal Vallis in 3D

The spacecraft captured these observations using its High Resolution Stereo Camera, an instrument that is mapping the whole surface Mars in full colour and at high resolution. Its aim – of characterising and understanding the Red Planet in its entirety – will be supported and continued by the ESA-Roscosmos ExoMars Trace Gas Orbiter, which arrived at Mars in 2016, and the ExoMars Rosalind Franklin rover and its accompanying surface science platform, which will arrive next year. Together, this ground-breaking fleet will help unlock the mysteries of Mars.

Related links:

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

High Resolution Stereo Camera: https://m.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_instruments

Trace Gas Orbiter (TGO): http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/First_results_from_the_ExoMars_Trace_Gas_Orbiter

ExoMars Rosalind Franklin rover: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_2020_rover

Images, Text, Credits:ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO/NASA MGS MOLA Science Team.

Greetings, Orbiter.ch

Health Checks, Science as Spacewalk Season Kicks Off on Station

ISS - Expedition 61 Mission patch.

October 8, 2019

Two NASA spacewalkers are conducting routine post-spacewalk activities today after a 7 hour, 1 minute spacewalk Sunday prior to another excursion outside the International Space Station this Friday.

Expedition 61 Flight Engineers Christina Koch and Andrew Morgan underwent a routine series of post-spacewalk health checks today with Commander Luca Parmitano assisting the astronauts.

Image above: NASA astronaut Andrew Morgan conducts a spacewalk on Oct. 6, 2019, to begin the latest round of upgrading the station’s large nickel-hydrogen batteries with newer, more powerful lithium-ion batteries. Image Credit: NASA.

Koch and Morgan will venture outside in their U.S. spacesuits again Friday for more battery replacement work on the P-6 truss structure. This time Morgan will lead the duo during the 6.5-hour spacewalk that will start at 7:50 a.m. EDT. NASA TV coverage begins at 6:30 a.m.

Parmitano and NASA Flight Engineer Jessica Meir joined the spacewalking duo during the afternoon to review the results and lessons learned from Sunday’s excursion. They will be back in the Quest airlock on Friday to help Morgan and Koch in and out of their spacesuits.

Three more spacewalks are planned before the month is out to complete the power upgrade work. The dates and astronauts for the upcoming spacewalks are…

    16: Andrew Morgan and Jessica Meir
    21: Christina Koch and Jessica Meir
    Oct: 25: Jessica Meir and Luca Parmitano

On the Russian side of the station, cosmonauts Alexander Skvortsov and Oleg Skripochka, who are scheduled to conduct their own spacewalk Oct. 31, continued the upkeep of life support systems while conducting microgravity research.

International Space Station (ISS). Animation Credit: NASA

Skvortsov, who has been on the station since July, explored how enzymes in the human body are impacted by weightlessness. Skripochka researched how ultraviolet waves affect Earth’s atmosphere.

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Quest airlock: https://www.nasa.gov/mission_pages/station/structure/elements/joint-quest-airlock

Spacewalks: http://www.nasa.gov/mission_pages/station/spacewalks

Enzymes in the human body: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1324

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

NASA's Curiosity Rover Finds an Ancient Oasis on Mars

NASA - Mars Science Laboratory (MSL) logo.

Oct. 8, 2019

Image above: The network of cracks in this Martian rock slab called "Old Soaker" may have formed from the drying of a mud layer more than 3 billion years ago. The view spans about 3 feet (90 centimeters) left-to-right and combines three images taken by the MAHLI camera on the arm of NASA's Curiosity Mars rover. Image Credits: NASA/JPL-Caltech/MSSS.

If you could travel back in time 3.5 billion years, what would Mars look like? The picture is evolving among scientists working with NASA's Curiosity rover.

Imagine ponds dotting the floor of Gale Crater, the 100-mile-wide (150-kilometer-wide) ancient basin that Curiosity is exploring. Streams might have laced the crater's walls, running toward its base. Watch history in fast forward, and you'd see these waterways overflow then dry up, a cycle that probably repeated itself numerous times over millions of years.

That is the landscape described by Curiosity scientists in a Nature Geoscience paper published today. The authors interpret rocks enriched in mineral salts discovered by the rover as evidence of shallow briny ponds that went through episodes of overflow and drying. The deposits serve as a watermark created by climate fluctuations as the Martian environment transitioned from a wetter one to the freezing desert it is today.

Scientists would like to understand how long this transition took and when exactly it occurred. This latest clue may be a sign of findings to come as Curiosity heads toward a region called the "sulfate-bearing unit," which is expected to have formed in an even drier environment. It represents a stark difference from lower down the mountain, where Curiosity discovered evidence of persistent freshwater lakes.

Gale Crater is the ancient remnant of a massive impact. Sediment carried by water and wind eventually filled in the crater floor, layer by layer. After the sediment hardened, wind carved the layered rock into the towering Mount Sharp, which Curiosity is climbing today. Now exposed on the mountain's slopes, each layer reveals a different era of Martian history and holds clues about the prevailing environment at the time.

A Guide to Gale Crater

"We went to Gale Crater because it preserves this unique record of a changing Mars," said lead author William Rapin of Caltech. "Understanding when and how the planet's climate started evolving is a piece of another puzzle: When and how long was Mars capable of supporting microbial life at the surface?"

He and his co-authors describe salts found across a 500-foot-tall (150-meter-tall) section of sedimentary rocks called "Sutton Island," which Curiosity visited in 2017. Based on a series of mud cracks at a location named "Old Soaker," the team already knew the area had intermittent drier periods. But the Sutton Island salts suggest the water also concentrated into brine.

Typically, when a lake dries up entirely, it leaves piles of pure salt crystals behind. But the Sutton Island salts are different: For one thing, they're mineral salts, not table salt. They're also mixed with sediment, suggesting they crystallized in a wet environment — possibly just beneath evaporating shallow ponds filled with briny water.

Given that Earth and Mars were similar in their early days, Rapin speculated that Sutton Island might have resembled saline lakes on South America's Altiplano. Streams and rivers flowing from mountain ranges into this arid, high-altitude plateau lead to closed basins similar to Mars' ancient Gale Crater. Lakes on the Altiplano are heavily influenced by climate in the same way as Gale.

"During drier periods, the Altiplano lakes become shallower, and some can dry out completely," Rapin said. "The fact that they're vegetation-free even makes them look a little like Mars."

Animation above: This animation demonstrates the salty ponds and streams that scientists think may have been left behind as Gale Crater dried out over time. The bottom of the image is the floor of Gale Crater, with the peak being the side of Mount Sharp. Animation Credits: ASU Knowledge Enterprise Development (KED), Michael Northrop.

Signs of a Drying Mars

Sutton Island's salt-enriched rocks are just one clue among several the rover team is using to piece together how the Martian climate changed. Looking across the entirety of Curiosity's journey, which began in 2012, the science team sees a cycle of wet to dry across long timescales on Mars.

"As we climb Mount Sharp, we see an overall trend from a wet landscape to a drier one," said Curiosity Project Scientist Ashwin Vasavada of NASA's Jet Propulsion Laboratory in Pasadena, California. JPL leads the Mars Science Laboratory mission that Curiosity is a part of. "But that trend didn't necessarily occur in a linear fashion. More likely, it was messy, including drier periods, like what we're seeing at Sutton Island, followed by wetter periods, like what we're seeing in the 'clay-bearing unit' that Curiosity is exploring today."

Up until now, the rover has encountered lots of flat sediment layers that had been gently deposited at the bottom of a lake. Team member Chris Fedo, who specializes in the study of sedimentary layers at the University of Tennessee, noted that Curiosity is currently running across large rock structures that could have formed only in a higher-energy environment such as a windswept area or flowing streams.

Wind or flowing water piles sediment into layers that gradually incline. When they harden into rock, they become large structures similar to "Teal Ridge," which Curiosity investigated this past summer.

"Finding inclined layers represents a major change, where the landscape isn't completely underwater anymore," said Fedo. "We may have left the era of deep lakes behind."

Curiosity has already spied more inclined layers in the distant sulfate-bearing unit. The science team plans to drive there in the next couple years and investigate its many rock structures. If they formed in drier conditions that persisted for a long period, that might mean that the clay-bearing unit represents an in-between stage — a gateway to a different era in Gale Crater's watery history.

"We can't say whether we're seeing wind or river deposits yet in the clay-bearing unit, but we're comfortable saying is it's definitely not the same thing as what came before or what lies ahead," Fedo said.

For more about NASA's Curiosity Mars rover mission, visit:

https://mars.nasa.gov/msl/

https://nasa.gov/msl

Images (mentioned), Video, Text, Credits: NASA/Jon Nelson/Alana Johnson/JPL/Andrew Good.

Greetings, Orbiter.ch

First of Five Power Upgrade Spacewalks This Month Wraps Up

ISS - Expedition 61 Mission patch / EVA - Extra Vehicular Activities patch.

October 6, 2019

Expedition 61 Flight Engineers Christina Koch and Andrew Morgan of NASA concluded their spacewalk at 2:40 p.m. EDT. During the seven-hour and one minute spacewalk, the two NASA astronauts began the replacement of nickel-hydrogen batteries with newer, more powerful lithium-ion batteries on the far end of the station’s port truss.

Astronauts also were able to accomplish get-ahead tasks, including the removal of an additional nickel-hydrogen battery, originally scheduled for the second spacewalk.

Image above: Astronauts Christina Koch and Andrew Morgan are pictured in their U.S. spacesuits during another spacewalk earlier this year. Image Credit: NASA.

These new batteries provide an improved power capacity for operations with a lighter mass and a smaller volume than the nickel-hydrogen batteries. On Oct. 11, Morgan and Koch are scheduled to venture outside again for another spacewalk to continue the battery replacements on the first of the two power channels for the station’s far port truss. The next spacewalks dedicated to the battery upgrades are scheduled on Oct. 16, 21 and 25.

After completion of the battery spacewalks, the second half of this sequence of spacewalks will focus on repairs to the space station’s Alpha Magnetic Spectrometer. Dates for those spacewalks still are being discussed, but they are expected to begin in November.

Space station crew members have conducted 219 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 57 days 6 hours and 27 minutes working outside the station.

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Alpha Magnetic Spectrometer (AMS): https://www.nasa.gov/feature/extending-science-in-the-search-for-the-origin-of-the-cosmos

Spot the Station: https://spotthestation.nasa.gov/

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

CASC - Long March-4C launches Gaofen-10

CASC - China Aerospace Science and Technology Corporation logo.

6 Oct. 2019

Long March-4C carrying Gaofen-10 lift off

A Long March-4C launch vehicle launched the Gaofen-10 satellite from the Taiyuan Satellite Launch Center, Shanxi Province, northern China, on 4 October 2019, at 18:51 UTC (5 October, at 02:51 local time).

Long March-4C launches Gaofen-10

Gaofen-10 (高分十号) is a microwave remote sensing satellite capable of providing photographs with a resolution of less than a meter, part of China’s high-definition Earth observation project.

Gaofen-10

According to official sources, Gaofen-10 will be used in land survey, urban planning, road network design, crop yield estimate, as well as disaster relief.

China Aerospace Science and Technology Corporation (CASC): http://english.spacechina.com/n16421/index.html

Images, Video, Text, Credits: CASC/China Central Television (CCTV)/SciNews/Günter's Space Page/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

Station Focuses on Busy Spacewalk Period After Trio Returns Home

ISS - Expedition 61 Mission patch.

October 6, 2019

The six-member Expedition 61 crew officially began Thursday morning after the departure of two Expedition 60 crewmates and a visiting astronaut. The current residents aboard the International Space Station now turn their attention to a series of spacewalks that begins Sunday.

Image above: The official Expedition 61 crew portrait with (from left) NASA astronaut Andrew Morgan, Roscosmos cosmonaut Alexander Skvortsov, astronaut Luca Parmitano of ESA (European Space Agency), Roscosmos cosmonaut Oleg Skripochka, and NASA astronauts Jessica Meir and Christina Koch. Image Credit: NASA.

NASA astronaut Nick Hague is returning to Houston after completing a 203-day mission aboard the orbiting lab with Roscosmos cosmonaut Alexey Ovchinin. The duo parachuted to Earth inside the Soyuz MS-12 crew ship and landed in Kazakhstan early Thursday with visiting astronaut Hazzaa Ali Almansoori of the United Arab Emirates. Ovchinin and Almansoori both returned to Star City, Russia.

Alpha Magnetic Spectrometer (AMS). Image Credit: NASA

Two NASA astronauts will exit the station’s Quest airlock in their U.S. spacesuits on Sunday at 7:50 a.m. EDT for a six-and-half hour spacewalk. Veteran spacewalkers Christina Koch and Andrew Morgan will begin the work to install new lithium-ion batteries on the Port-6 truss structure. This will be the first of five spacewalks in October to upgrade station power systems. Televised spacewalk coverage begins Sunday at 6:30 a.m.

Watch the spacewalk preview briefing that was broadcast Friday on NASA TV.

Upcoming spacewalk assignments:

    Oct. 5: Christina Koch and Andrew Morgan
    Oct. 11: Andrew Morgan and Christina Koch
    Oct. 16: Andrew Morgan and Jessica Meir
    Oct. 21: Christina Koch and Jessica Meir
    Oct. 25: Jessica Meir and Luca Parmitano
    Oct. 31: Oleg Skripochka and Alexander Skvortsov

Five more spacewalks are planned in November and December aimed at repairing the Alpha Magnetic Spectrometer.

For NASA TV streaming video: http://www.nasa.gov/nasatv

Related article:

Dressing for the Job: Spacesuits Prepped for Upcoming Spacewalks
https://orbiterchspacenews.blogspot.com/2019/10/dressing-for-job-spacesuits-prepped-for.html

Related links:

Expedition 60: https://www.nasa.gov/mission_pages/station/expeditions/expedition60/index.html

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Quest airlock: https://www.nasa.gov/mission_pages/station/structure/elements/joint-quest-airlock

Truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Spacewalks: http://www.nasa.gov/mission_pages/station/spacewalks

Spacewalk preview briefing: https://www.youtube.com/watch?v=2o4XMOj2zzY

Alpha Magnetic Spectrometer (AMS): https://www.nasa.gov/mission_pages/station/research/alpha-magnetic-spectrometer.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

Dressing for the Job: Spacesuits Prepped for Upcoming Spacewalks

ISS - International Space Station logo.

Oct. 5, 2019

NASA astronauts have been busy getting their spacesuits ready to go in preparation for a suite of 10 spacewalks outside the International Space Station. The first of five spacewalks to replace nickel-hydrogen batteries on the space station’s truss with newer, more powerful lithium-ion batteries is set to begin Sunday, Oct. 6, with four more following before the end of the month.

Another five spacewalks to repair the Alpha Magnetic Spectrometer—a cosmic ray catcher searching for evidence of “dark matter” in the universe and mounted on the exterior of the station—will follow in coming weeks.

The spacesuit worn during these excursions is the Extravehicular Mobility Unit, or EMU. This suit is essentially a personal spaceship that keeps astronauts safe and ensures they are able to perform complex, difficult work in the vacuum of space and the microgravity environment of low-Earth orbit. The spacesuit provides life support including breathing air and thermal controls, critical in space where temperatures range between plus or minus 250 degrees Fahrenheit, battery power, communication systems, and protection from radiation and tiny space debris—all of which are necessary for spacewalker safety and productivity.

Image above: Canadian Space Agency (CSA) astronaut David Saint-Jacques seen inside the Quest airlock replacing the Hard Upper Torso (HUT) on an Extravehicular Mobility Unit (EMU) aboard the International Space Station. Image Credit: NASA.

Once outside the safe haven of the orbital laboratory, astronauts typically spend about 6.5 hours spacewalking, not including the time it takes to prepare to float out of the hatch. Spacewalking is one of the most dangerous tasks performed during an astronaut’s mission, and to ensure top performance, safety and range of motion during the intense process that is a spacewalk, a properly fitting spacesuit is key.

Before ever launching to space, astronauts train for spacewalks at NASA’s Neutral Buoyancy Lab (NBL) located at the Johnson Space Center in Houston. This underwater laboratory simulates the microgravity environment of space by using foam and weights to make astronauts neutrally buoyant–they neither float to the top nor sink to the bottom of the pool.

Here, crewmembers are sized and fitted for each component of the spacesuit. EMU’s are made up of a collection of parts put together to fit a particular astronaut. The parts include the hard upper torso (HUT) that encloses the upper torso of the body, legs, lower arms, waists, boots, sizing rings and gloves. Each of these spacesuit components is interchangeable. There are three HUT sizes (medium, large and extra-large), four leg sizes, seven lower arm sizes, two waist sizes and two boot sizes. Due to the nature of spacewalks being hand intensive, and to ensure best fit for crewmembers, the glove fit is much more complicated and occasionally custom gloves are built for specific astronauts.

During ground training, astronauts evaluate suits of multiple sizes to improve planning flexibility on orbit. Some crewmembers fit only one size HUT, while others are able to fit between two sizes and could perform a spacewalk in multiple sizes, if necessary. While training at the NBL, astronauts can choose a prime and an alternative suit size based upon performance, fit, safety and a number of other factors.

Though suit sizes are determined on the ground, once on orbit, size adjustments can be made to take into account how astronauts’ bodies change during spaceflight. These changes require anywhere from 15 minutes of crew time for a minor adjustment, to up to 12 hours for a complete HUT removal and replacement task. If a complete HUT replacement is required in space, water inside the suit must be cleaned and checked for contamination; hardware must be physically changed out; and the various suit systems must be verified with the ground crews to confirm the suit is safe and ready to wear.

Aboard the International Space Station, NASA keeps enough components on hand to make four complete spacewalking suits, of which two HUTs of the same size can be available at any given time. The spacewalking suit sizes that are ready to go are based on the needs and preferences of the astronauts expected to wear them.

Due to a number of factors, ranging from safety to fit and performance, a crewmember may decide in orbit that their size preferences have changed. This is not uncommon, as astronauts’ bodies change on orbit and ground-based training can be different than performing spacewalks in the microgravity environment outside the space station. When that occurs, the teams on the ground determine what course of action will best accommodate both the astronauts’ preferences and the demands of the space station’s schedule.

For the upcoming series of 10 spacewalks, all of the spacewalkers prefer to use a medium HUT, so two medium sizes have been readied for duty. Each crew member will be able to perfect their suit’s sizing using the many adjustments available in the various components that make up their suit.

Live NASA Television coverage of the first spacewalk in the series will begin at 6:30 a.m. EDT Sunday, Oct, 6.

For NASA TV streaming video, schedule and downlink information, visit: http://www.nasa.gov/nasatv

Learn more about International Space Station research, operations and its crew at: http://www.nasa.gov/station

Image (mentioned), Text, Credits: NASA/Mark Garcia.

Greetings, Orbiter.ch