Who will be the first woman on the Moon?

NASA logo.

June 15, 2019

For the return to the moon decreed by Donald Trump, NASA promised that there would be an astronaut. Several candidates are favorites.

Anne McClain, a former army helicopter pilot, is one of the favorites. Image Credit: NASA

Twelve women are astronauts at NASA. The suspense is complete, but the woman who will walk on the Moon in 2024 is probably one of them. They are between 40 and 54 years old. They are former military pilots, doctors or PhDs, recruited from thousands by the US Space Agency since the late 1990s.

The twelve astronaut women of NASA. Image Credit: NASA

Predicting which will be chosen to join Neil Armstrong in the history books is impossible, but for several former astronauts and experts, the proximity of the deadline will force NASA to select one of twelve, rather than future beginners.

"I would not be opposed to sending a rookie. But there are enough astronauts who have already flown, who already know how they react in space, "says Eileen Collins, a former astronaut, who flew and commanded the Space Shuttle in the 1990s and 2000s.

"It would be better to send people who have already made at least one flight," said Ken Bowersox, a senior Nasa official. It will be all the easier as they have never been so numerous.

In the beginning, NASA only recruited soldiers and therefore men. The twelve astronauts who walked on the moon between 1969 and 1972 were all men. The first American in space was Sally Ride, in 1983. For the return to the moon decreed by Donald Trump, the program "Artemis", NASA promised that there would be an astronaut.

Anne, Christina, Jessica, Nicole

The four women of the 21st "promotion", recruited in 2013, will represent a good balance between youth and experience. Aged 40 or 41 today, they will each have made their first space stay by 2020.

Anne McClain, former helicopter pilot of the Army, is until end of June in the International Space Station (ISS). An assured look, a clear word, a slight smile: all his being expresses the ineffable "stuff of heroes", this tranquil force of character of the original recruits of NASA.

In the closed room of ISS also floats Christina Koch, engineer and passionate climbing. It will beat, with eleven months, the record of the longest female stay in space.

The duo almost made the first 100% female spacewalk, but a combination problem forced Anne McClain to give way to Nick Hague. "Christina Koch and Anne McClain are my two favorites," says Janet Ivey, host of a children's space show and board member of the National Space Society.

But their two classmates, marine biologist specialist of penguins and geese Jessica Meir and former F/A-18 test pilot  Nicole Mann, who participated in the wars in Iraq and Afghanistan, will be all also qualified: they are in full training to go to the ISS. In an interview in 2016, the four declared themselves to be volunteers for Mars if the opportunity arose. We can imagine them refusing the moon.

"Opaque" procedure

There is no age for space, they say to NASA. The mythical John Glenn had revolished at 77 years. Nothing therefore excludes the oldest astronaut, Sunita Williams, who is preparing his third space flight and will be 58 in 2024.

Especially since "Nasa has always appreciated the leadership qualities of the test pilots," says Kent Rominger, head of the astronaut's office from 2002 to 2006. "Suni" has flown about 30 aircraft in his military career.

Two other women, Serena Aunon-Chancellor and Kate Rubins, flew recently. Five women have not flown since at least 2010, but remain active.

Woman on the Moon (unknown source)

In the promotion recruited in 2017, there are five women, but their initial training is still not completed. They are not automatically excluded, but the schedule is unfavorable to them, especially as NASA tends to respect the order of seniority, notes Michael Lopez-Alegria, a former astronaut who spent 20 years at the agency.

In the end, the selection process "is quite opaque," he says, with experience. In Houston, the chief astronaut will be keen to compose a team whose profiles will be complementary, between ex-military and scientific, and between different personalities. The mission should have four crew members, two of whom will descend on the moon. Why not two women.

National Aeronautics and Space Administration (NASA): https://www.nasa.gov/

Images (mentioned), Text, Credits: AFP/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Today’s Advanced Research Goes From Free-flying Robots to Anti-Gravity Pants

ISS - Expedition 59 Mission patch.

June 14, 2019

Robotics, combustion and human research were the primary focus of today’s science schedule aboard the International Space Station. The Expedition 59 crewmembers also checked out U.S. spacesuits and specialized pants designed to counteract some of the effects of living in microgravity.

Astrobee, a tiny cube-shaped free-flying robotic assistant, is being tested aboard the orbital lab for its sighting and motion abilities. Flight Engineer David Saint-Jacques of the Canadian Space Agency (CSA) set up Astrobee for more mobility tests today inside the Japanese Kibo laboratory module. The device may support routine maintenance tasks and lab monitoring capabilities. Northrop Grumman’s Cygnus space freighter delivered Astrobee to the station April 19.

Image above: NASA astronaut Anne McClain checks out the new Astrobee robotics hardware earlier this year inside the Japanese Kibo laboratory module. Image Credit: NASA.

The safe observation of how fuels and materials burn in microgravity takes place in the space station’s Combustion Integrated Rack (CIR). The research takes place in the U.S. Destiny laboratory module and may help engineers design more fuel-efficient spacecraft engines and safer, less flammable environments. NASA astronaut Christina Koch replaced a burner and igniter tip in the CIR to maintain continuing combustion research operations.

Flight Engineer Anne McClain of NASA attached cuffs to her legs and sensors to her chest for a series of blood pressure checks and ultrasound scans today. The Vascular Echo biomedical study from CSA, ongoing since March 2015, analyzes an astronaut’s cardiovascular system for conditions such as arterial stiffness.

International Space Station (ISS). Animation Credit: NASA

U.S. spacesuits continue to be serviced after a set of three spacewalks that took place earlier this year. Astronaut Nick Hague cleaned the suit’s cooling loops, cycled their pressure valves and tested water samples inside the Quest airlock where U.S. spacewalks are staged.

Cosmonauts Oleg Kononenko and Alexey Ovchinin have been training this week to use the Lower Body Negative Pressure suit. The Russian suit, also known as Chibis, counteracts the upward fluid shifts in the human body caused by microgravity. This may alleviate the head and eye pressure reported by astronauts. An easily recognizable symptom of these fluid shifts that all crews experience is “puffy face.”

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Astrobee: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1891

Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Combustion Integrated Rack (CIR): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=317

U.S. Destiny laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/us-destiny-laboratory

Vascular Echo: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1664

Lower Body Negative Pressure suit: https://blogs.nasa.gov/ISS_Science_Blog/2015/06/02/rubber-vacuum-pants-that-suck/

Fluid shifts: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1126

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

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

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 to Partner with American Industry to Supply Artemis Moon Missions

NASA logo.

June 14, 2019

In the latest step in sending astronauts to the lunar surface within five years, NASA issued a draft solicitation June 14 to industry seeking comments for a future opportunity for American companies to deliver cargo and other supplies to the Gateway in lunar orbit.

Image above: Artist concept of the logistics module docked to Gateway in lunar orbit. NASA will seek solicitations from American companies to deliver cargo and other supplies to the lunar outpost that will support human exploration of the Moon by 2024.
Image Credit: NASA.

The first logistics service to the orbital outpost is expected to deliver science, cargo and other supplies in support of the agency’s new Artemis lunar exploration program, which includes sending the first woman and the next man to the surface of the Moon by 2024.

Last fall, NASA asked American companies for ideas on how to best supply the Gateway, which will be located in an orbit around the Moon about 250,000 miles from Earth. The Gateway will be a command and service module for missions to the lunar surface and eventually, exploration farther into the solar system. Following up on that initial request for information, today NASA published a draft solicitation for industry comments on its logistics approach, which are due July 10, 2019.

“We’re asking industry to provide a spacecraft to deliver cargo and other supplies to the Gateway. It will dock to the orbital outpost, but will be responsible for generating its own power,” said Marshall Smith, director, human lunar exploration programs at NASA Headquarters in Washington. “We’re using the Moon as a proving ground for Mars to develop the technologies and systems we need for exploration farther into the solar system, so we look forward to seeing how industry responds to our upcoming solicitation, and potentially awarding multiple contracts for this lunar service.”

This latest call is mirroring similar cargo resupply services the agency pioneered with industry closer to home. NASA led the way for commercialization of low-Earth orbit, and is now providing new opportunities for private companies in deep space.

“The Gateway, and specifically our logistics supply requirements, enables the deep space supply chain, taking the next step toward further commercialization of space,” said Mark Wiese, NASA’s Gateway logistics element manager at Kennedy Space Center in Florida. “In addition to delivering cargo, science and other supplies to the Gateway with these services, there’s potential for an extension to industry to deliver other elements of our lunar architecture with this solicitation.”

Lunar Gateway. Animation Credit: NASA

A formal solicitation for a firm-fixed price contract is expected this summer. NASA anticipates the maximum contract award for all Gateway services over the course of 15 years will be valued at $7 billion.

NASA will host an industry day forum in Florida on June 26 to answer questions and explain the proposed approach for logistic deliveries. Additional details about that opportunity for industry are available online: https://www.fbo.gov/spg/NASA/KSC/OPDC20220/80KSC019R0002-DRAFT/listing.html

This announcement comes on the heels of other recent agency efforts to accelerate its Moon to Mars exploration plans. At the end of May, NASA awarded a contract to Maxar Technologies to build, launch, and demonstrate in space the power and propulsion element of the Gateway. And ahead of sending astronauts to the Moon, the agency will use a series of commercial Moon deliveries to send a suite of science instruments and technology demonstrations to the surface to continue studying Earth’s nearest neighbor. NASA is also working with 11 companies to study the proposed architecture for a new integrated human landing system, which would be staged at the Gateway for missions to the lunar surface.

Charged with returning to the Moon within five years, NASA’s lunar exploration plans are based on a two-phase approach: the first is focused on speed – landing on the Moon by 2024 – while the second will establish a sustained human presence on and around the Moon by 2028. The agency will use what we learn on the Moon to prepare for the next giant leap – sending astronauts to Mars.

For more information about NASA’s Moon to Mars exploration plans, visit: https://www.nasa.gov/moontomars

Related articles and links:

Artemis: https://www.nasa.gov/subject/16957/artemis

NASA Selects First Commercial Moon Landing Services for Artemis Program
https://orbiterchspacenews.blogspot.com/2019/05/nasa-selects-first-commercial-moon.html

NASA Taps 11 American Companies to Advance Human Lunar Landers https://orbiterchspacenews.blogspot.com/2019/05/nasa-taps-11-american-companies-to.html

Sending American Astronauts to Moon in 2024: NASA Accepts Challenge https://orbiterchspacenews.blogspot.com/2019/04/sending-american-astronauts-to-moon-in.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Anna Heiney/KSC/Laura Aguiar.

Greetings, Orbiter.ch

Space Station Science Highlights: Week of June 10, 2019

ISS - Expedition 59 Mission patch.

June 14, 2019

Scientific investigations conducted on the International Space Station last week included work that could improve design of life support systems and help keep astronauts healthy on long missions. These types of investigations contribute valuable knowledge to NASA’s Artemis human exploration program. One of its goals is returning humans to the Moon by 2024 as a stepping stone to Mars.

Here are details on some of the scientific investigations the members of Expedition 59 conducted during the week of June 10:

Better management of fluids and gases

Image above: Hardware for the Capillary Structures investigation in the Japanese Experiment Module (JEM). This investigation studies using structures of specific shapes to manage fluid and gas mixtures and water recycling and carbon dioxide removal. This work benefits efforts to design lightweight, more reliable life support systems for future space missions. Image Credit: NASA.

The crew completed the current session for the ongoing Capillary Structures investigation, which studies using structures of specific shapes to manage fluid and gas mixtures. Current life-support systems on the space station require special equipment to separate liquids and gases, including rotating or moving devices that could cause contamination if they break or fail. This investigation looks at using different structures for water recycling and carbon dioxide removal systems, which could contribute to design of lightweight, more reliable life support systems for future space missions.

Getting their vitamins

Image above: These specially designed storage and growth packets contain engineered microbes for the BioNutrients investigation, which demonstrates a technology for on-demand production of nutrients during long-duration space missions. Image Credit: NASA.

BioNutrients demonstrates a technology to enable on-demand production of nutrients during long-duration space missions. Engineered microbes, such as yeast, generate carotenoids to supplement potential vitamin losses from food that is stored for a long time. During the five-year investigation, crew members intermittently activate specially designed storage and growth packets then freeze them for return to Earth for analysis. Last week, the crew processed eight packets for incubation and then placed them into Minus Eighty Degree Celsius Laboratory Freezer for ISS (MELFI).

Waiting to exhale

Last week, the crew conducted the final session for Airway Monitoring. This investigation analyzes exhaled air to determine the occurrence and indicators of airway inflammation due to dust particles in the space station. During future crewed missions to the Moon and Mars, airway inflammation due to dust inhalation presents a risk, and this work helps in the development of countermeasures to that risk. It also supports crew member health on future longer-duration missions to the Moon and Mars by helping make these missions more self-sufficient in avoiding potential problems with dust inhalation.

Other investigations on which the crew performed work:

- The Astrobee free-flying robots test technology for assisting astronauts with routine chores and giving ground controllers additional eyes and ears on the space station: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1891

- The Photobioreactor investigation demonstrates whether the biological processes of microalgae can serve as part of a hybrid life support system. This approach would help future long-duration exploration missions reduce the amount of supplies required from Earth: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7426

Image above: NASA astronaut Anne McClain using the Liquid Exchange Device to fill the Photobioreactor with medium and algae to begin the experiment. This investigation examines creating a hybrid life support system with microalgae, which could help future long-duration exploration missions by reducing the amount of consumables required from Earth. Image Credit: NASA.

- The ISS Experience documents daily life aboard the space station through a virtual reality film to educate a variety of audiences about life in the orbiting lab and science conducted there: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7877

- Food Acceptability examines changes in the appeal of food aboard the space station during long-duration missions. “Menu fatigue” from repeatedly consuming a limited choice of foods may contribute to the loss of body mass often experienced by crew members, potentially affecting astronaut health, especially as mission length increases: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562

- Veg-04 focuses on how light quality and fertilizer affect growth of a leafy crop, along with microbial food safety, nutritional value, taste acceptability by the crew, and the overall behavioral health benefits of having plants and fresh food in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7896

- Probiotics examines the effects of beneficial bacteria or probiotics on the intestinal microbiota and immune function of crew members on long-duration space missions: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2047

- FLUIDICS uses a sphere in microgravity to represent a spacecraft’s fuel tank in order to analyze slosh and wave turbulence of a fluid. Results could support development of better fuel systems for satellites and future spacecraft: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2043

- Standard Measures captures a consistent and simple set of measures from crew members throughout the ISS Program in order to characterize adaptive responses to and risks of living in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7711

Space to Ground: Open for Business: 06/14/2019

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Capillary Structures: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7329

BioNutrients: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7400

Eighty Degree Celsius Laboratory Freezer for ISS (MELFI): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=56

Airway Monitoring: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1067

Artemis: https://www.nasa.gov/feature/what-is-artemis/

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

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Jorge Sotomayor, Lead Increment Scientist Expeditions 59/60.

Best regards, Orbiter.ch

Space agencies come together

ESA - European Space Agency logo & JAXA - Japan Aerospace Exploration Agency logo.

14 June 2019

On 14 June, President Hiroshi Yamakawa of JAXA was welcomed at the 282nd meeting of the ESA Council – the Agency’s governing body – held at ESA’s Operations Centre in Darmstadt, Germany.

BepiColombo approaching Mercury

For decades, the European Space Agency and the Japan Aerospace Exploration Agency, JAXA, have worked in close collaboration to better understand our Universe.

From Earth observation missions to spacecraft exploring Martian moons, Mercury or distant asteroids, ESA and JAXA continue to show how international cooperation makes space exploration more effective and ultimately more successful.

Decades of cooperation

On his first visit to ESA mission control, President Yamakawa delivered a presentation highlighting 40 years of cooperation between ESA and JAXA, most recently illustrated by the launch of BepiColombo, the joint ESA–JAXA mission currently en route to Mercury.

“We are thrilled to welcome President Yamakawa into the heart of Europe’s mission control centre,” said Rolf Densing, ESA’s Director of Operations.

“Our agencies have achieved a great deal together so far, and we are looking forward to many more shared adventures in future.”

Eyes on Earth

The European and Japanese space agencies also recognise the huge importance of space missions to deliver better understanding of our changing planet by gathering data crucial for Earth science and for tackling climate change.

EarthCARE

The joint ESA–JAXA EarthCARE satellite will include four cutting-edge sensors, including the first Doppler radar in space, the Cloud Profiling Radar, provided by JAXA. As well as providing this critical instrument, JAXA will be responsible for a portion of the science data processing and distribution, ensuring the information can be used by scientists worldwide.

Similarly, ESA is distributing data from JAXA’s GOSAT-1 and -2 satellites across Europe, both providing critical new information on greenhouse gases in our atmosphere.

A phenomenal agreement

During the ESA Council meeting in Darmstadt, ESA Director General Jan Wörner and President Yamakawa signed an agreement on XRISM – the X-ray Imaging and Spectroscopy Mission – which will study extremely energetic phenomena in the Universe.

ESA and JAXA join forces to understand the hot gas plasma wind

XRISM will be launched in the early 2020s from the Tanegashima Space Center, Japan, with hardware components and support for science management and planning provided by ESA. In return, ESA will be granted observation time, to be allocated to scientists affiliated to institutions in ESA Member States.

Delving into deep space

As well as XRISM, ESA and JAXA are working on a number of missions taking us from our home planet out into deep space, including the JAXA-led Martian Moons eXploration mission and the ESA-led missions JUICE, studying Jupiter’s icy moons, and SPICA, ESA’s Space Infrared Telescope for Cosmology and Astrophysics.

Io transits Jupiter

On the ground, ESA and JAXA are planning a feasibility study for a much-needed new antenna, which would increase capacity to communicate with future missions.

Deep-space communication is vital to the success of all missions. ESA ground stations supported JAXA’s Hayabusa-2 spacecraft, which arrived at asteroid Ryugu last year.

Protecting our planet

The two agency leaders also recognised the importance of space safety activities to protect people, the planet and global space infrastructure from hazards such as near-Earth asteroids, space weather and space debris, as well as cybersecurity threats originating on Earth.

“While competition is undeniably a driver, cooperation can be a powerful enabler. In the cooperation with JAXA, the European Space Agency demonstrates its expertise in international partnership,” concludes Jan Wörner, ESA Director General.

“Together, we travel further, explore deeper and understand the Universe and ourselves better.”

Related links:

ESA–JAXA EarthCARE: http://www.esa.int/Our_Activities/Observing_the_Earth/The_Living_Planet_Programme/Earth_Explorers/EarthCARE/ESA_s_cloud_aerosol_and_radiation_mission

JAXA’s GOSAT-1 and -2 satellites:
https://directory.eoportal.org/web/eoportal/satellite-missions/g/gosat

https://directory.eoportal.org/web/eoportal/satellite-missions/g/gosat-2

XRISM: http://xrism.isas.jaxa.jp/en/

JAXA-led Martian Moons eXploration: http://mmx.isas.jaxa.jp/en/

ESA's JUICE: http://www.esa.int/Our_Activities/Space_Science/ESA_s_Jupiter_mission_moves_off_the_drawing_board

ESA's SPICA: http://www.esa.int/Our_Activities/Space_Engineering_Technology/CDF/M5_CDF_Studies

Space safety: http://www.esa.int/Our_Activities/Space_Safety/Space_Safety

Japan Aerospace Exploration Agency (JAXA): https://global.jaxa.jp/

European Space Agency (ESA): http://www.esa.int/ESA

Images, Text, Credits: ESA/P. Carril/ATG medialab; Mercury: NASA/JPL/University of Arizona.

Best regards, Orbiter.ch

How NASA's Spitzer Has Stayed Alive for So Long

NASA - Spitzer Space Telescope patch.

June 14, 2019

After nearly 16 years of exploring the cosmos in infrared light, NASA's Spitzer Space Telescope will be switched off permanently on Jan. 30, 2020. By then, the spacecraft will have operated for more than 11 years beyond its prime mission, thanks to the Spitzer engineering team's ability to address unique challenges as the telescope slips farther and farther from Earth.

Managed and operated by NASA's Jet Propulsion Laboratory in Pasadena, California, Spitzer is a small but transformational observatory. It captures infrared light, which is often emitted by "warm" objects that aren't quite hot enough to radiate visible light. Spitzer has lifted the veil on hidden objects in nearly every corner of the universe, from a new ring around Saturn to observations of some of the most distant galaxies known. It has spied stars in every stage of life, mapped our home galaxy, captured gorgeous images of nebulas and probed newly discovered planets orbiting distant stars.

Image above: This artist's concept shows NASA's Spitzer Space Telescope in front of an infrared image of the Milky Way galaxy. Image Credits: NASA/JPL-Caltech.

But as Spitzer's deputy mission manager, Joseph Hunt, said, "You can have a world-class spacecraft, but it doesn't mean anything if you can't get the data back home."

Spitzer orbits the Sun on a path similar to Earth's but moves slightly slower. Today it trails about 158 million miles (254 million kilometers) behind our planet - more than 600 times the distance between Earth and the Moon. That distance, along with the curve of Spitzer's orbit, means that when the spacecraft points its fixed antenna at Earth to download data or receive commands, its solar panels tilt away from the Sun. During those periods, the spacecraft must rely on a combination of solar power and battery power to operate.

The angle at which the panels point away from the Sun has increased every year that the mission has been operating. These days, to communicate with Earth, Spitzer has to position its panels at a 53-degree angle away from the Sun (90 degrees would be fully facing away), even though the mission planners never intended for it to tilt more than 30 degrees from the Sun. Spitzer can communicate with Earth for about 2.5 hours before it has to turn its solar panels back toward the Sun to recharge its batteries. That communications window would grow shorter year after year if Spitzer continued operating, which means there is a limit to how long it would be possible to operate the spacecraft efficiently.

An Enduring Effort

Teaching the spacecraft to accept new conditions - such as the increasing angle of the solar panels during communications with Earth - isn't as simple as flipping a switch. There are multiple ways these changes could trigger safety mechanisms in the spacecraft's flight software. For instance, if the panels tilted more than 30 degrees from the Sun during the mission's early years, the software would have hit "pause," putting the spacecraft into "safe mode" until the mission team could figure out what was wrong. The changing angle of Spitzer to the Sun could also trigger safety mechanisms intended to prevent spacecraft parts from overheating.

Entering safe mode can be particularly hazardous for the spacecraft, both because of its growing distance from Earth (which makes communicating more difficult) and because the aging onboard systems might not restart once they shut off.

To deal with these challenges, the project engineers and scientists at JPL and Caltech have worked with the observatory engineering team at Lockheed Martin Space's Littleton, Colorado, facility to find a path forward. (Lockheed Martin built the Spitzer spacecraft for NASA.) Bolinda Kahr, Spitzer's mission manager, leads this multi-center team. Over the years she and her colleagues have successfully figured out how to override safety mechanisms designed for the prime mission while also making sure that such alterations don't introduce other unwanted side effects.

But as Spitzer ages and gets farther from Earth, the challenge of keeping the spacecraft operating and the risk that it will suffer a major anomaly are only increasing.

"I can genuinely say that no one involved in the mission planning thought we'd be running in 2019," said Lisa Storrie-Lombardi, Spitzer's project manager. "But we have an incredibly robust spacecraft and an incredible team. And we've been lucky. You have to have some luck, because you can't anticipate everything."

Keeping Cool

Most infrared detectors have to be cooled to very low temperatures, because excess infrared light from "warm" objects - including the Sun, Earth, the spacecraft and even the instruments themselves - can overwhelm the infrared sensors. This cooling is typically done with a chemical coolant.

The Spitzer planners instead came up with a passive-cooling system that included flying the spacecraft far from Earth (a major infrared heat source). They also chose materials for the spacecraft exterior that would both reflect sunlight away before it could heat the telescope and radiate absorbed heat back into space. In this configuration, coolant is required only to lower the instrument temperatures a few degrees further. Reducing the onboard coolant supply also drastically allowed the engineers to cut the total size of the spacecraft by more than 80% and helped curtail the anticipated mission budget by more than 75%.

Spitzer Space Telescope. Animation Credits: NASA/JPL

Although Spitzer's coolant supply ran out in 2009, rendering two of its three instruments unusable, the team was able to keep half of the remaining instrument operating. (The instrument was designed to detect four wavelengths of infrared light; in the "warm" mode, it can still detect two of them.)

Lasting more than twice as long as the primary mission, Spitzer's extended mission has yielded some of the observatory's most transformational results. In 2017, the telescope revealed the presence of seven rocky planets around the TRAPPIST-1 star. In many cases, Spitzer's exoplanet observations were combined with observations by other missions, including NASA's Kepler and Hubble space telescopes.

Spitzer's final year and a half of science operations include a number of exoplanet-related investigations. One program will investigate 15 dwarf stars (similar to the TRAPPIST-1 star) likely to host exoplanets. An additional 650 hours are dedicated to follow-up observations of planets discovered by NASA's Transiting Exoplanet Survey Satellite (TESS), which launched just over a year ago.

Final Voyage

Every mission must end at some point. As the challenges associated with operating Spitzer continue to grow and as the risk of a mission-ending anomaly on the spacecraft rises, NASA has made the decision to close out the mission in a controlled manner.

"There have been times when the Spitzer mission could have ended in a way we didn't plan for," said Kahr. "I'm glad that in January we'll be able to retire the spacecraft deliberately, the way we want to do it."

While Spitzer's mission is ending, it has helped set the stage for NASA's James Webb Space Telescope, set to launch in 2021, which will study the universe in many of the same wavelengths observed by Spitzer. Webb's primary mirror is about 7.5 times larger than Spitzer's mirror, meaning Webb will be able to study many of the same targets in much higher resolution and objects much farther away from Earth than what Spitzer can observe.

Thirteen science programs have already been selected for Webb's first five months of operations, four of which build directly on Spitzer observations. Webb will greatly expand on the legacy begun by Spitzer and answer questions that Spitzer has only begun to investigate.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

Related links:

NASA's Transiting Exoplanet Survey Satellite (TESS):
https://www.nasa.gov/tess-transiting-exoplanet-survey-satellite

NASA's James Webb Space Telescope (JWST): https://www.jwst.nasa.gov/

For more information on Spitzer, visit:

http://www.nasa.gov/spitzer

http://www.spitzer.caltech.edu/

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Calla Cofield.

Greetings, Orbiter.ch

SpaceX - Radarsat Constellation Mission Success

SpaceX - Falcon 9 / RADARSAT Constellation Mission patch.

June 13, 2019

Re-used SpaceX Rocket Launches 3 RADARSAT Satellites

A SpaceX Falcon 9 rocket launched the RADARSAT Constellation Mission (RCM) from Space Launch Complex 4E (SLC-4E) at Vandenberg Air Force Base in California, on 12 June 2019, at 14:17 UTC UTC (07:17 PDT). Following stage separation, Falcon 9’s first stage (Block 5 B1051) landed on SpaceX’s Landing Zone 4 (LZ-4) at Vandenberg Air Force Base. Falcon 9’s first stage for this mission previously supported Crew Dragon’s first demonstration mission in March 2019. The RADARSAT Constellation Mission (RCM) consists of three identical C-band Synthetic Aperture Radar (SAR) Earth observation satellites.

SpaceX RCM mission: Falcon 9 launch and landing

A SpaceX Falcon 9 rocket launches the RADARSAT Constellation Mission for the Canadian Space Agency and MDA.

RADARSAT Constellation

Consisting of three radar Earth observation spacecraft launching on a single rocket, the RADARSAT Constellation Mission is the next in a series of Canadian RADARSAT satellites supporting all-weather maritime surveillance, disaster management and ecosystem monitoring for the Canadian government and international users.

RADARSAT Constellation Mission: http://www.asc-csa.gc.ca/eng/satellites/radarsat/default.asp

For more information about SpaceX, visit: https://www.spacex.com/

Images, Video, Text, Credits: SpaceX/SciNews/Orbiter,ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

Crew Preps for Split, Studies Space Effects on Human Body

ISS - Expedition 59 Mission patch.

June 13, 2019

The Expedition 59 crew will split up later this month when three International Space Station residents return to Earth. The other three crewmembers today practiced evacuating the orbiting lab in the unlikely event of an emergency.

Station Commander Oleg Kononenko will depart home with Flight Engineers Anne McClain and David Saint-Jacques inside the Soyuz MS-11 crew ship on June 24. The trio have been living in space since Dec. 3 and will have orbited Earth for 204 days after landing in Kazakhstan. The commander spent the day Thursday collecting cargo for stowage and readying the homebound Soyuz.

Image above: The aurora australis, or “southern lights,” highlights a starry nighttime orbital pass as the International Space Station orbited 269 miles above the Indian Ocean southwest of Australia. Image Credit: NASA.

The three crewmembers that are staying behind conducted an emergency drill during the afternoon. Flight Engineers Alexey Ovchinin, Christina Koch and Nick Hague conducted an emergency simulation and rehearsed quickly entering their Soyuz lifeboat, undocking and descending to Earth.

Human research continued full speed ahead today to help doctors keep astronauts healthy in space. McClain and Hague once again collected their breath samples for the Airway Monitoring study. The experiment studies airway inflammation as crewmembers on space missions are at an increased risk of breathing free-floating dust and particles due to the microgravity environment. Results could improve the mission environment and optimize crew health for successful long-term missions. Saint-Jacques participated in ultrasound scans of his neck, gut, heart and leg throughout the day. The ground-assisted Vascular Echo scans give flight surgeons insight into an astronaut’s cardiovascular condition.

Seeing an Aurora From the Space Station

Image above: Aboard the International Space Station, NASA astronaut Christina Koch snapped this image of an aurora, saying: "Years ago at the South Pole, I looked up to the aurora for inspiration through the 6-month winter night. Now I know they’re just as awe inspiring from above. #nofilter". Image Credit: NASA.

The crew also worked on robotics power cables and the installation of a small satellite deployer. Koch installed cables in the Unity module during the morning to provide backup power for the Canadarm2 robotic arm. McClain spent the majority of her day in Japan’s Kibo laboratory module installing hardware that will soon eject a set of CubeSats outside the station for research in Earth orbit.

The two cosmonauts, Kononenko and Ovchinin, spent some time in the morning exploring ways to counteract the effects of microgravity. The duo tested a unique suit that draws body fluids towards the feet to minimize head and eye pressure.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Airway Monitoring: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1067

Vascular Echo: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1664

Unity module: https://www.nasa.gov/mission_pages/station/structure/elements/unity

Canadarm2: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Unique suit: https://blogs.nasa.gov/ISS_Science_Blog/2015/06/02/rubber-vacuum-pants-that-suck/

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/Yvette Smith.

Best regards, Orbiter.ch

NASA's Cassini Reveals New Sculpting in Saturn Rings

NASA - Cassini Mission to Saturn patch.

June 13, 2019

As NASA's Cassini dove close to Saturn in its final year, the spacecraft provided intricate detail on the workings of Saturn's complex rings, new analysis shows.

Although the mission ended in 2017, science continues to flow from the data collected. A new paper published June 13 in Science describes results from four Cassini instruments taking their closest-ever observations of the main rings.

Image above: A false-color image mosaic shows Daphnis, one of Saturn's ring-embedded moons, and the waves it kicks up in the Keeler gap. Images collected by Cassini's close orbits in 2017 are offering new insight into the complex workings of the rings. Image Credits: NASA/JPL-Caltech/Space Science Institute.

Findings include fine details of features sculpted by masses embedded within the rings. Textures and patterns, from clumpy to strawlike, pop out of the images, raising questions about the interactions that shaped them. New maps reveal how colors, chemistry and temperature change across the rings.

Like a planet under construction inside a disk of protoplanetary material, tiny moons embedded in Saturn's rings (named A through G, in order of their discovery) interact with the particles around them. In that way, the paper provides further evidence that the rings are a window into the astrophysical disk processes that shape our solar system.

Images above:  New images of Saturn's rings show how textures differ even in close proximity of one another. The first image has been filtered so that the newly visible strawlike textures and clumps are more visible. Images Credits: NASA/JPL-Caltech/Space Science Institute.

The observations also deepen scientists' understanding of the complex Saturn system. Scientists conclude that at the outer edge of the main rings, a series of similar impact-generated streaks in the F ring have the same length and orientation, showing that they were likely caused by a flock of impactors that all struck the ring at the same time. This shows that the ring is shaped by streams of material that orbit Saturn itself rather than, for instance, by cometary debris (moving around the Sun) that happens to crash into the rings.

"These new details of how the moons are sculpting the rings in various ways provide a window into solar system formation, where you also have disks evolving under the influence of masses embedded within them," said lead author and Cassini scientist Matt Tiscareno of the SETI Institute in Mountain View, California.

Enduring Mysteries

At the same time, new puzzles have arisen and old mysteries have deepened with the latest research. The close-up ring images brought into focus three distinct textures — clumpy, smooth and streaky — and made it clear that these textures occur in belts with sharp boundaries. But why? In many places the belts aren't connected to any ring characteristics that scientists have yet identified.

"This tells us the way the rings look is not just a function of how much material there is," Tiscareno said. "There has to be something different about the characteristics of the particles, perhaps affecting what happens when two ring particles collide and bounce off each other. And we don't yet know what it is."

Image above: This false-color image to the right shows an infrared spectral map of Saturn's A, B and C rings, captured by Cassini's VIMS. Infrared image credit: NASA/JPL-Caltech/University of Arizona/CNRS/LPG-Nantes Saturn image credit: NASA/JPL-Caltech/Space Science Institute/G. Ugarkovic.

The data analyzed were gathered during the Ring Grazing Orbits (December 2016 to April 2017) and the Grand Finale (April to September 2017), when Cassini flew just above Saturn's cloud tops. As the spacecraft was running out of fuel, the mission team deliberately plunged it into the planet's atmosphere in September 2017.

Cassini's Visible and Infrared Mapping Spectrometer (VIMS) uncovered another mystery. The spectrometer, which imaged the rings in visible and near-infrared light, identified unusually weak water-ice bands in the outermost part of the A ring. That was a surprise, because the area is known to be highly reflective, which usually is a sign of less-contaminated ice and thus stronger water ice bands.

The new spectral map also sheds light on the composition of the rings. And while scientists already knew that water ice is the main component, the spectral map ruled out detectable ammonia ice and methane ice as ingredients. But it also doesn't see organic compounds — a surprise, given the organic material Cassini has discovered flowing from the D ring into Saturn's atmosphere.

"If organics were there in large amounts — at least in the main A, B and C rings — we'd see them," said Phil Nicholson, Cassini VIMS scientist of Cornell University in Ithaca, New York. "I'm not convinced yet that they are a major component of the main rings."

The research signals the start of the next era of Cassini science, said NASA's Ames Research Center's Jeff Cuzzi, who's been studying Saturn's rings since the 1970s and is the interdisciplinary scientist for rings on the Cassini mission.

Cassini Grand Final. Animation Credit: NASA

"We see so much more, and closer up, and we're getting new and more interesting puzzles," Cuzzi said. "We are just settling into the next phase, which is building new, detailed models of ring evolution — including the new revelation from Cassini data that the rings are much younger than Saturn."

The new observations give scientists an even more intimate view of the rings than they had before, and each examination reveals new complexities, said Cassini Project Scientist Linda Spilker, based at NASA’s Jet Propulsion Laboratory in Pasadena, California.

"It's like turning the power up one more notch on what we could see in the rings. Everyone just got a clearer view of what's going on," Spilker said. "Getting that extra resolution answered many questions, but so many tantalizing ones remain."

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter. The radio antenna was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.

More information about Cassini can be found here: https://solarsystem.nasa.gov/cassini and https://www.nasa.gov/mission_pages/cassini/main/index.html

Images (mentioned), Text, Credits: NASA/Tony Greicius/JoAnna Wendel/JPL/Gretchen McCartney/Jia-Rui Cook.

Best regards, Orbiter.ch

NASA’s Fermi Mission Reveals its Highest-energy Gamma-ray Bursts

NASA - Fermi Gamma-ray Space Telescope logo.

June 13, 2019

For 10 years, NASA’s Fermi Gamma-ray Space Telescope has scanned the sky for gamma-ray bursts (GRBs), the universe’s most luminous explosions. A new catalog of the highest-energy blasts provides scientists with fresh insights into how they work.

“Each burst is in some way unique,” said Magnus Axelsson, an astrophysicist at Stockholm University in Sweden. “It’s only when we can study large samples, as in this catalog, that we begin to understand the common features of GRBs. These in turn give us clues to the physical mechanisms at work.”

The catalog was published in the June 13 edition of The Astrophysical Journal and is now available online. More than 120 authors contributed to the paper, led by Axelsson, Elisabetta Bissaldi at the National Institute of Nuclear Physics and Polytechnic University in Bari, Italy, and Nicola Omodei and Giacomo Vianello at Stanford University in California.

Image above: This illustration shows NASA’s Fermi Gamma-ray Space Telescope, which observes the sky in gamma rays, the highest-energy form of light. Image Credits: NASA's Goddard Space Flight Center.

GRBs emit gamma rays, the highest-energy form of light. Most GRBs occur when some types of massive stars run out of fuel and collapse to create new black holes. Others happen when two neutron stars, superdense remnants of stellar explosions, merge. Both kinds of cataclysmic events create jets of particles that move near the speed of light. The gamma rays are produced in collisions of fast-moving material inside the jets and when the jets interact with the environment around the star.

Astronomers can distinguish the two GRB classes by the duration of their lower-energy gamma rays. Short bursts from neutron star mergers last less than 2 seconds, while long bursts typically continue for a minute or more. The new catalog, which includes 17 short and 169 long bursts, describes 186 events seen by Fermi’s Large Area Telescope (LAT) over the last 10 years.

Fermi observes these powerful bursts using two instruments. The LAT sees about one-fifth of the sky at any time and records gamma rays with energies above 30 million electron volts (MeV) — millions of times the energy of visible light. The Gamma-ray Burst Monitor (GBM) sees the entire sky that isn’t blocked by Earth and detects lower-energy emission. All told, the GBM has detected more than 2,300 GRBs so far.

Below is a sample of five record-setting and intriguing events from the LAT catalog that have helped scientists learn more about GRBs.

Image above: Green dots show the locations of 186 gamma-ray bursts observed by the Large Area Telescope (LAT) on NASA’s Fermi satellite during its first decade. Some noteworthy bursts are highlighted and labeled. Background: Constructed from nine years of LAT data, this map shows how the gamma-ray sky appears at energies above 10 billion electron volts. The plane of our Milky Way galaxy runs along the middle of the plot. Brighter colors indicate brighter gamma-ray sources. Image Credits: NASA/DOE/Fermi LAT Collaboration.

1. GRB 081102B

The short burst 081102B, which occurred in the constellation Boötes on Nov. 2, 2008, is the briefest LAT-detected GRB, lasting just one-tenth of a second. Although this burst appeared in Fermi’s first year of observations, it wasn’t included in an earlier version of the collection published in 2013.

“The first LAT catalog only identified 35 GRBs,” Bissaldi said. “Thanks to improved data analysis techniques, we were able to confirm some of the marginal observations in that sample, as well as identify five times as many bursts for the new catalog.”

2. GRB 160623A

Long-lived burst 160623A, spotted on June 23, 2016, in the constellation Cygnus, kept shining for almost 10 hours at LAT energies — the longest burst in the catalog. But at the lower energies recorded by Fermi's GBM instrument, it was detected for only 107 seconds. This stark difference between the instruments confirms a trend hinted at in the first LAT catalog. For both long and short bursts, the high-energy gamma-ray emission lasts longer than the low-energy emission and happens later.

3. GRB 130427A
 

Overview Animation of Gamma-ray Burst

Video above: This animation shows the most common type of gamma-ray burst, which occurs when the core of a massive star collapses, forms a black hole, and blasts particle jets outward at nearly the speed of light. Viewing into a jet greatly boosts its apparent brightness. A Fermi image of GRB 130427A ends the sequence. Video Credits: NASA’s Goddard Space Flight Center.

The highest-energy individual gamma ray detected by Fermi’s LAT reached 94 billion electron volts (GeV) and traveled 3.8 billion light-years from the constellation Leo. It was emitted by 130427A, which also holds the record for the most gamma rays — 17 — with energies above 10 GeV.

A popular model proposed that charged particles in the jet, moving at nearly the speed of light, encounter a shock wave and suddenly change direction, emitting gamma rays as a result. But this model can’t account for the record-setting light from this burst, forcing scientists to rethink their theories.

The original findings on 130427A show that the LAT instrument tracked its emission for twice as long as indicated in the catalog. Due to the large sample size, the team adopted the same standardized analysis for all GRBs, resulting in slightly different numbers than reported in the earlier study.

4. GRB 080916C
 

Fermi LAT movie of Gamma-ray Burst (GRB) 080916C

Video above: This movie shows Fermi Large Area Telescope observations of GRB 080916C. About 8 minutes of data are compressed into 6 seconds. Colored dots represent gamma rays of different energies. The blue dots represent lower-energy gamma rays; green, moderate energies; and red, the highest energies. Video Credits: NASA/DOE/Fermi LAT Collaboration.

The farthest known GRB occurred 12.2 billion light-years away in the constellation Carina. Called 080916C, researchers calculate the explosion contained the power of 9,000 supernovae.

Telescopes can observe GRBs out to these great distances because they are so bright, but pinpointing their exact distance is difficult. Distances are only known for 34 of the 186 events in the new catalog.

5. GRB 090510

The known distance to 090510 helped test Einstein’s theory that the fabric of space-time is smooth and continuous. Fermi detected both a high-energy and a low-energy gamma ray at nearly the same instant. Having traveled the same distance in the same amount of time, they showed that all light, no matter its energy, moves at the same speed through the vacuum of space.

“The total gamma-ray emission from 090510 lasted less than 3 minutes, yet it allowed us to probe this very fundamental question about the physics of our cosmos,” Omodei said. “GRBs are really one of the most spectacular astronomical events that we witness.”

What’s missing?

GRB 170817A marked the first time light and ripples in space-time, called gravitational waves, were detected from the merger of two neutron stars. The event was captured by the Laser Interferometer Gravitational Wave Observatory (LIGO), the Virgo interferometer and Fermi's GBM instrument, but it wasn’t observed by the LAT because the instrument was switched off as the spacecraft passed through a region of Fermi’s orbit where particle activity is high.

“Now that LIGO and Virgo have begun another observation period, the astrophysics community will be on the lookout for more joint GRB and gravitational wave events” said Judy Racusin, a co-author and a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This catalog was a monumental team effort, and the result helps us learn about the population of these events and prepares us for delving into future groundbreaking finds.”

The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

Related links:

Laser Interferometer Gravitational Wave Observatory (LIGO): https://www.ligo.caltech.edu/

Fermi Gamma-Ray Space Telescope: http://www.nasa.gov/mission_pages/GLAST/main/index.html

Gamma-Ray Bursts: https://www.nasa.gov/subject/8730/gammaray-bursts

Images (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Jeanette Kazmierczak.

Greetings, Orbiter.ch

Table Salt Compound Spotted on Europa

JPL - Jet Propulsion Laboratory logo.

June 13, 2019

A familiar ingredient has been hiding in plain sight on the surface of Jupiter's moon Europa. Using a visible-light spectral analysis, planetary scientists at Caltech and NASA's Jet Propulsion Laboratory in Pasadena, California, have discovered that the yellow color visible on portions of the surface of Europa is actually sodium chloride, a compound known on Earth as table salt, which is also the principal component of sea salt.

The discovery suggests that the salty subsurface ocean of Europa may chemically resemble Earth's oceans more than previously thought, challenging decades of supposition about the composition of those waters. The finding was published by Science Advances on June 12.

Europa Global Views in Natural and Enhanced Colors

Image above: Tara Regio is the yellowish area to left of center, in this NASA Galileo image of Europa's surface. This region of geologic chaos is the area researchers identified an abundance of sodium chloride. Image Credits: NASA/JPL/University of Arizona.

Flybys from NASA's Voyager and Galileo spacecraft have led scientists to conclude that Europa is covered by a layer of salty liquid water encased in an icy shell. Galileo carried an infrared spectrometer, an instrument scientists use to examine the composition of a surface they're studying. Galileo's spectrometer found water ice and a substance that appeared to be magnesium sulfate salts (like Epsom salts). Since the icy shell is geologically young and features abundant evidence of past geologic activity, it was suspected that whatever salts exist on the surface may derive from the ocean below.

"People have traditionally assumed that all of the interesting spectroscopy is in the infrared on planetary surfaces, because that's where most of the molecules that scientists are looking for have their fundamental features," said Mike Brown, the Richard and Barbara Rosenberg Professor of Planetary Astronomy at Caltech and coauthor of the Science Advances paper.

"No one has taken visible-wavelength spectra of Europa before that had this sort of spatial and spectral resolution. The Galileo spacecraft didn't have a visible spectrometer. It just had a near-infrared spectrometer, and in the near-infrared, chlorides are featureless," said Caltech graduate student Samantha Trumbo, lead author of the paper.

That all changed when new, higher spectral resolution data from the W. M. Keck Observatory on the dormant volcano Maunakea in Hawaii suggested that the scientists weren't actually seeing magnesium sulfates on Europa. Most of the sulfate salts considered previously possess distinct absorptions, which serve as fingerprints for compounds, that should have been visible in the higher-quality Keck data. However, the spectra of regions expected to reflect the internal composition lacked any of the characteristic sulfate absorptions.

Europa Lab Turns White Salt Yellow

Image above: In a laboratory simulating conditions on Jupiter's moon Europa at NASA's Jet Propulsion Laboratory in Pasadena, California, plain white table salt (sodium chloride) turned yellow (visible in a small well at the center of this photograph). The color is significant because scientists can now deduce that the yellow color previously observed on portions of the surface of Europa is actually sodium chloride. The JPL lab experiments matched temperature, pressure and electron radiation conditions at Europa's surface. Image Credits: NASA/JPL-Caltech.

"We thought that we might be seeing sodium chlorides, but they are essentially featureless in an infrared spectrum," Brown said.

Meanwhile, JPL scientist Kevin Hand had used sample ocean salts, bombarded by radiation in a laboratory under Europa-like conditions, and found that several new and distinct features arose in sodium chloride after irradiation. He discovered that they changed colors to the point that they could be identified with an analysis of the visible spectrum. Sodium chloride, for example, turned a shade of yellow similar to that visible in a geologically young area of Europa known as "Tara Regio."

"Sodium chloride is a bit like invisible ink on Europa's surface. Before irradiation you can't tell it's there, but after irradiation the color jumps right out at you," said Hand.

By taking a close look with the NASA/ESA Hubble Space Telescope, the research team was able to identify a distinct absorption in the visible spectrum at 450 nanometers, which matched the irradiated salt precisely, confirming that the yellow color of Tara Regio reflected the presence of irradiated sodium chloride on the surface.

"We've had the capacity to do this analysis with the Hubble Space Telescope for the past 20 years," Brown said. "It's just that nobody thought to look."

While the finding does not guarantee that this sodium chloride is derived from the subsurface ocean (this could, in fact, simply be evidence of different types of materials stratified in the moon's icy shell), the study's authors propose that it warrants a reevaluation of the geochemistry of Europa.

"Magnesium sulfate would simply have leached into the ocean from rocks on the ocean floor, but sodium chloride may indicate the ocean floor is hydrothermally active," Trumbo said. "That would mean Europa is a more geologically interesting planetary body than previously believed."

The study is titled "Sodium chloride on the surface of Europa." This research was supported by the NASA Earth and Space Science Fellowship Program, the Space Telescope Science Institute, and JPL, which is managed by Caltech for NASA.

JPL - Jet Propulsion Laboratory: https://www.jpl.nasa.gov/

Images (mentioned), Text, Credits: NASA/JoAnna Wendel/JPL/Gretchen McCartney/Jia-Rui Cook/Caltech/Robert Perkins.

Greetings, Orbiter.ch