samedi 6 juin 2020

U.S. Companies Advance Critical Human Lander Technologies

NASA - Artemis Program logo.

June 6, 2020

NASA and 11 commercial partners recently completed a series of technical studies, demonstrations and ground prototypes for 21st Century human landing systems. The Next Space Technology Exploration Partnerships (NextSTEP) Appendix E work helped the agency refine its Artemis program requirements for the companies competing to build the landers that will take American astronauts to the Moon throughout this decade.

NASA’s Human Exploration and Operations Mission Directorate and Space Technology Mission Directorate funded the 11 companies that led the Appendix E work: Aerojet Rocketdyne of Canoga Park, California; Blue Origin of Kent, Washington; Boeing of Houston, Texas; Dynetics of Huntsville, Alabama; Lockheed Martin of Littleton, Colorado; Masten Space Systems of Mojave, California; Maxar Technologies of Westminster, Colorado; Northrop Grumman of Dulles, Virginia; Orbit Beyond of Edison, New Jersey; Sierra Nevada Corporation of Louisville, Colorado; and SpaceX of Hawthorne, California.

Image above: Compilation of artist's renderings representing NextSTEP Appendix E work. Top row, left to right: Dynetics, Lockheed Martin, Blue Origin. Bottom row, left to right: Aerojet Rocketdyne, Northrop Grumman, Masten Space System, Boeing.

Through the Appendix E contracts, NASA gained valuable insight into architecture options and key technologies necessary for the new human landers, with a focus on spacecraft elements for lunar descent, in-space transfer, and refueling.

“The Appendix E results have made us smarter buyers for the human landing systems now under development, one of which we expect will ultimately land the first humans on the Moon since 1972,” said Nantel Suzuki, human landing system program executive at NASA Headquarters in Washington. “By engaging a broad cross-section of the space industry in these studies, we were able to improve and validate our lander requirements, and we now have a much deeper understanding of the greatest technological challenges involved with safely landing our astronauts on new locations of the lunar surface and returning them home.”

Since the vice president directed NASA in March 2019 to return humans to the Moon by 2024, America’s space industry has been bustling to help the agency realize this ambitious goal.

“Under Appendix E alone, the amount of work completed in less than a year is very impressive,” said  Suzuki, who led the formulation of Appendix E as well as the follow-on Appendix H solicitation to industry for the human landing system. “The 2024 mission timeline has focused NASA to find the most efficient ways to work with the private sector and meet this challenge.”

Seven out of the 11 companies conducted demonstrations or built prototypes to address cryogenic fluid management. Cryogenic propellants are gases such as oxygen, methane, and hydrogen that are cooled to very cold (cryogenic) temperatures until they are in a liquid state that requires less volume—i.e., more usable energy in smaller tanks. Cryogenic space propulsion systems exhibit very high performance, but even the slightest source of ambient heat generated by the vehicle itself, or changes in pressure due to the vacuum of space, can lead to “boil off” or loss of fuel as it reverts to its gaseous state and vents from the tank.

NASA saw the companies develop new approaches for cryogenic tank design and insulation, improvements to filling and draining the tanks in a vacuum, and cryocooler implementation to address cryogenic boil off challenges. Some companies also focused on storable propellants like hydrazine, which do not boil off like cryogenics and are often used for long duration space missions. NASA’s Voyager 1 spacecraft, for instance, has been cruising the solar system for more than 42 years on the same tank of hydrazine in its propulsion system.

Appendix E propellant transfer studies provided keen insight into the challenges of moving propellants, including cryogenics, between lander elements in space—so they can be replenished after boil off, or refueled between missions and reused.

Moon Lander

Automated rendezvous and proximity operations and docking (RPOD) was another area of focus for the companies. RPOD will be a key procedure in lunar operations, where much of the vehicle aggregation of separately-launched lander elements may happen without crew aboard to oversee vehicle dockings. Companies used ground-based testbeds to validate rendezvous and proximity operations technology, and also examined common sensors like optical cameras and LIDAR that are useful for proximity operations, precision landing, and hazard avoidance.

Precision landing and hazard avoidance technologies also earned well-deserved attention in Appendix E. Apollo 11 enthusiasts may recall the harrowing landing during which Neil Armstrong and Buzz Aldrin found themselves off-course and quickly descending into an alarming combination of a crater field littered with boulders. They were able to take manual control and land safely on the surface with less than 6% fuel in the tank.

“We want human landers that rely on modern precision landing and hazard avoidance technologies,” said Greg Chavers, human landing system deputy program manager at NASA’s Marshall Spaceflight Center in Huntsville, Alabama. “Our astronauts will be trained to fly these spacecraft, but we believe industry can build on existing technologies to refine these systems and reduce the need for human control.”

In fact, much of the Appendix E precision landing and hazard avoidance work extended the capabilities of proven flight heritage systems. Other studies examined newer technologies, incorporating precision landing sensors into conceptual lander designs and performing software demonstrations to match real-time imagery with detailed lunar surface maps.

“It’s difficult to articulate the sheer quality and quantity of data that has been revealed through Appendix E,” remarked Chavers. “Perhaps equally important are the ways that we learned to work with the companies to remove traditional barriers and use more streamlined methods to share data between the government and private sector. That will be chiefly important as we focus the same NASA workforce to team with Blue Origin, Dynetics and SpaceX as they develop their human lander concepts. To land humans on the Moon in 2024, we need the best of U.S. industry and the best of NASA to work together to achieve such a monumental goal.”

Charged with returning to the Moon in 2024, NASA’s Artemis program  will reveal new knowledge about the Moon, Earth and our origins in the solar system. The human landing system, and its core technologies, are a vital part of NASA’s deep space exploration plans, along with the Gateway, Space Launch System (SLS) rocket, and Orion spacecraft that will send astronauts to the Moon. Gaining new experiences on and around the Moon will prepare NASA to send the first humans to Mars in the coming years, and the human landing system will play a vital role in this process.

For more information about NASA’s Moon to Mars exploration plans, visit:

Artemis program:

Space Launch System (SLS):


Voyager 1:

Next Space Technology Exploration Partnerships (NextSTEP)
Appendix E:

Images, Text, Credits: NASA/Erin Mahoney.


NASA Awards Northrop Grumman Artemis Contract for Gateway Crew Cabin

International Lunar Gateway patch.

June 6, 2020

NASA has finalized the contract for the initial crew module of the agency’s Gateway lunar orbiting outpost.

Image above: Artist's concept of the Gateway power and propulsion and Habitation and Logistics Outpost, or HALO, in orbit around the Moon. Image Credit: NASA.

Orbital Science Corporation of Dulles, Virginia, a wholly owned subsidiary of Northrop Grumman Space, has been awarded $187 million to design the habitation and logistics outpost (HALO) for the Gateway, which is part of NASA’s Artemis program and will help the agency build a sustainable presence at the Moon. This award funds HALO’s design through its preliminary design review, expected by the end of 2020.

“This contract award is another significant milestone in our plan to build robust and sustainable lunar operations,” said NASA Administrator Jim Bridenstine. “The Gateway is a key component of NASA’s long-term Artemis architecture and the HALO capability furthers our plans for human exploration at the Moon in preparation for future human missions to Mars.”

The HALO will be the pressurized living quarters where astronauts will spend their time while visiting the Gateway. About the size of a small studio apartment, it will provide augmented life support in tandem with NASA’s Orion spacecraft.

The preliminary design review is one of a series of checkpoints in the design life cycle of a complex engineering project before hardware manufacturing can begin. As the review process progresses, details of the vehicle’s design are assessed to ensure the overall system is safe and reliable for flight and meets all NASA mission requirements.

This cost plus incentive fee contract allows Northrop Grumman to finalize the design of all systems and subsystems. It also provides for the company to award initial subcontracts for long-lead hardware elements. A second contract action is expected to be definitized by the end of the year for Northrop Grumman to fabricate and assemble HALO for integration with the Gateway’s power and propulsion element (PPE) by the end of 2023.

These first two elements of the Gateway – HALO and PPE – will launch together in 2023. This is a recent update to the agency’s plans to build a sustainable presence at the Moon as part of the Artemis program. The decision to integrate the elements on the ground prior to launch – an outcome of the agency’s program status assessment – reduces both cost and technical risks while enhancing the likelihood of mission success by eliminating the need for the two elements to dock in the orbit around the Moon where the Gateway will operate.

“We’re making significant progress on these first two elements, including incorporation of components from ESA (European Space Agency), the Canadian Space Agency, the Japan Aerospace Exploration Agency, and payloads from our research communities,” said Dan Hartman, Gateway program manager at NASA’s Johnson Space Center in Houston. “The new plan to integrate the two elements of Gateway demonstrates the capabilities of the agency and our partners to be flexible and reassess plans as needed. By launching the elements together, we’re able to significantly reduce Gateway’s risk profile and increase cost effectiveness.”

Lunar Gateway. Animation Credit: ESA

The PPE, being designed and built by Maxar Technologies, is equipped with high-power, 60-kilowatt solar electric propulsion. In addition to providing power and communications, its substantial maneuvering capabilities will allow the Gateway to change orbits and enable crews to reach any part of the Moon’s surface.

Northrop Grumman’s habitation module, developed through NASA’s NextSTEP initiative, is based on its Cygnus spacecraft currently being used to deliver cargo to the International Space Station. The company’s existing production capability and manufacturing assets allow it to build the HALO with limited schedule risk. NASA’s Launch Services Program will select a launch provider for PPE and HALO by late fall 2020.

Charged with returning to the Moon in the next four years, NASA’s Artemis program  will reveal new knowledge about the Moon, Earth, and our origins in the solar system. The Gateway is a vital part of NASA’s deep space exploration plans, along with the Space Launch System (SLS) rocket, Orion spacecraft, and the human landing system that will carry astronauts to the surface of the Moon in preparation for NASA to sending humans on a historic first journey to Mars.

For more information about NASA’s Gateway program, visit:

Related links:

Maxar Technologies:

Artemis program:

Space Launch System (SLS):


Moon to Mars:

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Katherine Brown/Gina Anderson/JSC/Isidro Reyna/Rachel Kraft.


vendredi 5 juin 2020

New SpaceX Crewmates Wrap Up First Workweek Aboard Station

ISS - Expedition 63 Mission patch / NASA & SpaceX - Dragon Demo-2 - Behnken & Hurley patch.

June 5, 2020

The Expedition 63 crew and its two newest crewmates aboard the International Space Station wrapped up the workweek studying a wide range of space phenomena.

Image above: Flying over South Pacific Ocean, seen by EarthCam on ISS, speed: 27'568 Km/h, altitude: 423,60 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Now Live application with EarthCam's from ISS on June 5, 2020 at 18:50 UTC. Image Credits: ISS Live Now/ Aerospace/Roland Berga.

Commander Chris Cassidy began Friday setting up optical communications gear aboard the Japanese Kibo laboratory module. The new broadband hardware will demonstrate transmitting large amounts of data back and forth from the station to the ground. Afterward, the NASA astronaut swapped out test samples for an experiment taking place inside the Materials Science Laboratory.

Image above: NASA astronauts (from left) Bob Behnken, Doug Hurley and Chris Cassidy are the U.S. members of the Expedition 63 crew. Image Credit: NASA.

New station Flight Engineers Doug Hurley and Bob Behnken are still in a handover period as they wrap up their first work week in space. The astronauts familiarized themselves today with medical kits, the food pantry, communication systems and safety procedures. They also continued researching space bubbles in microfluids and unpacked Japan’s HTV-9 resupply ship, which arrived six days before they did.

Image above: Previously recorded image of HTV-9 resupply ship and Canadarm seen by EarthCam on ISS, speed: 27'568 Km/h, altitude: 423,60 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Now Live application with EarthCam's from ISS on June 5, 2020 at 18:50 UTC. Image Credits: ISS Live Now/ Aerospace/Roland Berga.

Roscosmos Flight Engineers Anatoly Ivanishin and Ivan Vagner kept up this week’s research as they photographed natural and man-made impacts on Earth and monitored the station’s radiation environment. The duo also continued inspecting the orbiting lab’s Russian modules while videotaping their station activities for Earth audiences.

Related links:

Expedition 63:

Optical communications gear:

Kibo laboratory module:

Materials Science Laboratory:

Space bubbles in microfluids:

HTV-9 resupply ship:

Natural and man-made impacts:

Station’s radiation environment:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Catherine Williams/ Aerospace/Roland Berga.


Space Station Science Highlights: Week of June 1, 2020

ISS - Expedition 63 Mission patch.

June 5, 2020

Scientific studies conducted on the International Space Station during the week of June 1 included research on clean flames and electrolytic gas evolution in microgravity. The week also brought the historic arrival of NASA astronauts Robert Behnken and Douglas Hurley aboard the Space-X Demo 2 Dragon spacecraft.

Image above: The SpaceX Crew Dragon, right center, approaches the International Space Station with astronauts Doug Hurley and Bob Behnken of NASA's Commercial Crew Program aboard just before docking to the Harmony module's forward International Docking Adapter. Image Credit: NASA.

Now in its 20th year of continuous human presence, the space station provides a platform for long-duration research in microgravity and for learning to live and work in space. NASA’s Commercial Crew Program, once again launching astronauts on American rockets and spacecraft from American soil, increases the crew-time available for science on the orbiting lab.

Here are details on some of the microgravity investigations currently taking place:

Moving fluids with bubbles

Image above: NASA astronaut Chris Cassidy sets up for the Electrolysis Measurement investigation, which examines the influence of gravity on electrolytic gas evolution. Image Credit: NASA.

Electrolytic Gas Evolution Under Microgravity (Electrolysis Measurement) examines the influence of gravity on electrolytic gas evolution. Electrolysis uses electrodes to pass an electric current through a substance and separate out gasses in the form of bubbles. The process can be used in microfluidic devices to produce oxygen in spacecraft and future human habitations on the Moon and Mars. On Earth, the technology could be used in patches used to deliver medication doses through the skin. Microgravity makes it possible to single out bubble growth and study its effect on the process. During the week, the crew set up and initiated the experiment.

Cleaner, more efficient flames

During the week, the crew made changes for different runs of the Structure and Response of Spherical Diffusion Flames (s-Flame) investigation. This experiment is part of the Advanced Combustion via Microgravity Experiments (ACME) project, a series of independent studies of gaseous flames performed in the station’s Combustion Integrated Rack (CIR). In particular, s-Flame advances prediction of the structure and dynamics of soot-free and sooty flames with the goal of improving fuel efficiency and reducing pollutants in routine fuel combustion activities on Earth. It also could contribute to better spacecraft fire prevention through innovative research focused on materials flammability.

Keeping an eye on upper-atmosphere lightning

Image above: The Atmosphere-Space Interactions Monitor (ASIM), an ESA Earth observation facility on the exterior of the space station, studies severe thunderstorms and their role in the Earth’s atmosphere and climate. Image Credit: NASA.

Some investigations aboard the space station require little or no involvement by the crew, thanks to increasing automation and coordination with ground teams. One such investigation under way this week from the ESA (European Space Agency) is Atmosphere-Space Interactions Monitor (ASIM), an Earth observation facility studying severe thunderstorms and their role in the Earth’s atmosphere and climate. Upper-atmospheric lightning, known as transient luminous events or terrestrial gamma-ray flashes, occurs well above the altitudes of normal lightning and storm clouds, and the space station’s low-Earth orbit provides an ideal platform for measuring them. ASIM collects data when an atmospheric event is detected or when an observation is planned ahead of time, and the start and duration are programmed by a team on the ground.

Related article:

Discovering the Inner Life of Lightning from the International Space Station

Other investigations on which the crew performed work:

- Scientists are studying melting of materials in the Japan Aerospace Exploration Agency (JAXA) Electrostatic Levitation Furnace (ELF). Reactions between raw materials melted to make glass and metals and the crucible or container that holds them can cause imperfections. To prevent these reactions, scientists use static electricity to cause the materials to levitate or float, which is much easier in microgravity than on Earth.

- Materials manufactured from liquid metal could revolutionize production of future spacecraft and other hardware. Round Robin, an investigation from JAXA, measures the properties of molten metals in microgravity to improve models of flow of liquids in manufacturing processes.

- For The ISS Experience, astronauts film different aspects of crew life, execution of science and the international partnerships involved on the space station. Footage will be used to create a virtual reality series that gives audiences a tangible experience of the challenges of adapting to life in space, the work and science conducted on the space station and the human interaction between astronauts.

- Hourglass, another JAXA investigation, examines the behavior under different gravity conditions of various granular materials that simulate regolith, a dust that covers the surface of planets and planetary-like bodies.

Space to Ground: A New Endeavour: 06/05/2020

Related links:

Expedition 63:

Commercial Crew Program:

Electrolysis Measurement:



Combustion Integrated Rack (CIR):

Atmosphere-Space Interactions Monitor (ASIM):

ISS National Lab:

Spot the Station:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/John Love, Lead Increment Scientist Expedition 63.

Best regards,

Hubble Catches Cosmic Snowflakes

NASA - Hubble Space Telescope patch.

June 5, 2020

Almost like snowflakes, the stars of the globular cluster NGC 6441 sparkle peacefully in the night sky, about 13,000 light-years from the Milky Way’s galactic center. Like snowflakes, the exact number of stars in such a cluster is difficult to discern. It is estimated that together the stars have 1.6 million times the mass of the Sun, making NGC 6441 one of the most massive and luminous globular clusters in the Milky Way.

NGC 6441 is host to four pulsars that each complete a single rotation in a few milliseconds. Also hidden within this cluster is JaFu 2, a planetary nebula. Despite their name, planetary nebulas have little to do with planets. A phase in the evolution of intermediate-mass stars, planetary nebulas last for only a few tens of thousands of years, the blink of an eye on astronomical timescales.

There are about 150 known globular clusters in the Milky Way. Globular clusters contain some of the first stars to be produced in a galaxy, but the details of their origins and evolution still elude astronomers.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation Credits: ESA/Hubble & NASA, G. Piotto.

Best regards,

NASA Infrared Imagery Indicates Cristobal’s Heavy Rainmaking Capabilities

NASA - EOS Aqua Mission logo / JPL - Atmospheric Infrared Sounder  (AIRS) patch.

June 5, 2020

Cristobal (was 03L) – Atlantic Ocean

One of the ways NASA observes tropical cyclones is by using infrared data that provides temperature information and indicates storm strength. The AIRS instrument aboard NASA’s Aqua satellite gathered that data and revealed Cristobal has the potential to generate heavy rainfall. That rainfall is now soaking Mexico and portions of Central America as Cristobal meanders.

Image above: On June 3 at 3:11 p.m. EDT (1911 UTC) NASA’s Aqua satellite analyzed Tropical Storm Cristobal using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than (purple) minus 63 degrees Fahrenheit (minus 53 degrees Celsius) east of center over Mexico’s Yucatan Peninsula. Image Credit: NASA JPL/Heidar Thrastarson.

At 9:35 a.m. EDT on Wednesday, June 3, Tropical Storm Cristobal made landfall in the Mexican state over Campeche, just to the west of Ciudad del Carmen. At the time of landfall, maximum winds were estimated to be 60 mph (95 kph) with higher gusts. Since landfall, Cristobal weakened to a depression, and moved very slowly in a southeasterly direction into northwestern Guatemala. As the storm weakened, it expanded, now heavy rainfall is expected in Mexico, Guatemala, El Salvador, Belize and Honduras.

Damaging and deadly flooding has already been occurring in portions of Mexico and Central America. Cristobal is expected to produce additional extreme rainfall amounts through the end of the week.

Colder Cloud Top Temperatures Indicate Strength

Cloud top temperatures provide information to forecasters about where the strongest storms are located within a tropical cyclone. Tropical cyclones do not always have uniform strength, and some sides are stronger than others. The stronger the storms, the higher they extend into the troposphere, and the colder the cloud temperatures.

NASA provides this infrared data to forecasters at NOAA’s National Hurricane Center (NHC) so they can incorporate in their forecasting. That data is reflected in the NHC forecasts of rainfall amounts.

Artist's rendering of NASA's Aqua Satellite Orbiting Earth. Image Credit: NASA

On June 3 at 3:11 p.m. EDT (1911 UTC) NASA’s Aqua satellite analyzed Tropical Storm Cristobal using the Atmospheric Infrared Sounder or AIRS instrument. AIRS found coldest cloud top temperatures as cold as or colder than minus 63 degrees Fahrenheit (minus 53 degrees Celsius) south and east of center, over Mexico’s Yucatan Peninsula.  NASA research has shown that cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.

A Look at Extreme Rainfall Potential

NHC forecasters using infrared and other satellite data noted that Cristobal is expected to produce high rain accumulations through Saturday, June 6. NHC noted,”The Mexican states of Campeche, Quintana Roo, Tabasco, and Yucatan are expected to receive an additional 6 to 12 inches, with isolated storm totals of 25 inches.

Mexican states of Veracruz and Oaxaca can expect an additional 5 to 10 inches, while southern Guatemala and parts of Chiapas can expect an additional 15 to 20 inches, and isolated storm total amounts of 35 inches dating back to Saturday, May 30. El Salvador can also expect an additional 10 to 15 inches, with isolated storm total amounts of 35 inches dating back to Saturday, May 30. In Belize and Honduras, an additional 3 to 6 inches with isolated amounts to 10 inches are forecast.

Rainfall in all of these areas may produce life-threatening flash floods and mudslides.”

Cristobal on June 4, 2020

NOAA’s National Hurricane Center updated Cristobal’s status on June 4 at 11 a.m. EDT (1500 UTC) and noted that since it made landfall on June 3, it had weakened to a depression. The center of Tropical Depression Cristobal was located near latitude 17.6 degrees north and longitude 91.0 degrees west. That places the center of Cristobal about 160 miles (260 km) south-southwest of Campeche, Mexico.

The depression is moving toward the east-southeast near 3 mph (6 kph). The estimated minimum central pressure is 998 millibars. Maximum sustained winds have decreased to near 35 mph (55 kph) with higher gusts. Little change in strength is expected through tonight [June 4].  Re-intensification is expected to begin on Friday.

Cristobal’s Forecast Path

Forecasters at the NHC said that Cristobal is expected to turn back into the Gulf of Mexico after moving over extreme northwestern Guatemala and eastern Mexico today and tonight. The center is forecast to move back over the southern Gulf of Mexico [June 5] Friday day or Friday night, over the central Gulf of Mexico on Saturday, and approach the northern Gulf of Mexico coast [June 7] Sunday day and Sunday night.

The AIRS instrument is one of six instruments flying on board NASA’s Aqua satellite, launched on May 4, 2002.

Related links:

NASA’s Aqua satellite:

Atmospheric Infrared Sounder or AIRS instrument:

For updated forecasts, visit:

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center, by Rob Gutro.


JPL Mission Breaks Record for Smallest Satellite to Detect an Exoplanet

JPL - Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) logo.

June 5, 2020

About the size of a briefcase, the CubeSat was built to test new technologies but exceeded expectations by spotting a planet outside our solar system.

Animation above: Caption: ASTERIA was deployed from the International Space Station on November 20, 2017. Animation Credits: NASA/JPL-Caltech.

Long before it was deployed into low-Earth orbit from the International Space Station in Nov. 2017, the tiny ASTERIA spacecraft had a big goal: to prove that a satellite roughly the size of a briefcase could perform some of the complex tasks much larger space observatories use to study exoplanets, or planets outside our solar system. A new paper soon to be published in the Astronomical Journal describes how ASTERIA (short for Arcsecond Space Telescope Enabling Research in Astrophysics) didn't just demonstrate it could perform those tasks but went above and beyond, detecting the known exoplanet 55 Cancri e.

Scorching hot and about twice the size of Earth, 55 Cancri e orbits extremely close to its Sun-like parent star. Scientists already knew the planet's location; looking for it was a way to test ASTERIA's capabilities. The tiny spacecraft wasn't initially designed to perform science; rather, as a technology demonstration, the mission's goal was to develop new capabilities for future missions. The team's technological leap was to build a small spacecraft that could conduct fine pointing control - essentially the ability to stay very steadily focused on an object for long periods.

Image above: Left to right: Electrical Test Engineer Esha Murty and Integration and Test Lead Cody Colley prepare the ASTERIA spacecraft for mass-properties measurements in April 2017 prior to spacecraft delivery ahead of launch. ASTERIA was deployed from the International Space Station in November 2017. Image Credits: NASA/JPL-Caltech.

Based at NASA's Jet Propulsion Laboratory in Southern California and at the Massachusetts Institute of Technology, the mission team engineered new instruments and hardware, pushing past existing technological barriers to create their payload. Then they had to test their prototype in space. Though its prime mission was only 90 days, ASTERIA received three mission extensions before the team lost contact with it last December.

The CubeSat used fine pointing control to detect 55 Cancri e via the transit method, in which scientists look for dips in the brightness of a star caused by a passing planet. When making exoplanet detections this way, a spacecraft's own movements or vibrations can produce jiggles in the data that could be misinterpreted as changes in the star's brightness. The spacecraft needs to stay steady and keep the star centered in its field of view. This allows scientists to accurately measure the star's brightness and identify the tiny changes that indicate the planet has passed in front of it, blocking some of its light.

Image above: The super-Earth exoplanet 55 Cancri e, depicted with its star in this artist's concept, likely has an atmosphere thicker than Earth's but with ingredients that could be similar to those of Earth's atmosphere. Image Credits: NASA/JPL-Caltech.

ASTERIA follows in the footsteps of a small satellite flown by the Canadian Space Agency called MOST (Microvariability and Oscillations of Stars), which in 2011 performed the first transit detection of 55 Cancri e. MOST was about six times the volume of ASTERIA - still incredibly small for an astrophysics satellite. Equipped with a 5.9-inch (15-centimeter) telescope, MOST was also capable of collecting six times as much light as ASTERIA, which carried 2.4-inch (6-centimeter) telescope. Because 55 Cancri e blocks out only 0.04% of its host star's light, it was an especially challenging target for ASTERIA.

"Detecting this exoplanet is exciting, because it shows how these new technologies come together in a real application," said Vanessa Bailey, the principal investigator for ASTERIA's exoplanet science team at JPL. "The fact that ASTERIA lasted more than 20 months beyond its prime mission, giving us valuable extra time to do science, highlights the great engineering that was done at JPL and MIT."

Big Feat

The mission made what's known as a marginal detection, meaning the data from the transit would not, on its own, have convinced scientists that the planet existed. (Faint signals that look similar to a planet transit can be caused by other phenomena, so scientists have a high standard for declaring a planet detection.) But by comparing the CubeSat's data with previous observations of the planet, the team confirmed that they were indeed seeing 55 Cancri e. As a tech demo, ASTERIA also didn't undergo the typical prelaunch preparations for a science mission, which meant the team had to do additional work to ensure the accuracy of their detection.

"We went after a hard target with a small telescope that was not even optimized to make science detections - and we got it, even if just barely," said Mary Knapp, the ASTERIA project scientist at MIT's Haystack Observatory and lead author of the study. "I think this paper validates the concept that motivated the ASTERIA mission: that small spacecraft can contribute something to astrophysics and astronomy."

While it would be impossible to pack all the capabilities of a larger exoplanet-hunting spacecraft like NASA's Transiting Exoplanet Survey Satellite (TESS) into a CubeSat, the ASTERIA team envisions these petite packages playing a supporting role for them. Small satellites, with fewer demands on their time, could be used to monitor a star for long periods in hopes of detecting an undiscovered planet. Or, after a large observatory discovers a planet transiting its star, a small satellite could watch for subsequent transits, freeing up the larger telescope to do work smaller satellites can't.

Astrophysicist Sara Seager, principal investigator for ASTERIA at MIT, was recently awarded a NASA Astrophysics Science SmallSat Studies grant to develop a mission concept for a follow-on to ASTERIA. The proposal describes a constellation of six satellites about twice as big as ASTERIA that would search for exoplanets similar in size to Earth around nearby Sun-like stars.

Thinking Small

To build the smallest planet-hunting satellite in history, the ASTERIA wasn't simply shrinking hardware used on larger spacecraft. In many cases, they had to take a more innovative approach. For example, the MOST satellite used a camera with a charge-coupled device (CCD) detector, which is common for space satellites; ASTERIA, on the other hand, was equipped with a complementary metal-oxide-semiconductor (CMOS) detector - a well-established technology typically used for making precision measurements of brightness in infrared light, not visible light. ASTERIA's CMOS-based, visible-light camera provided multiple advantages over a CCD. One big one: It helped keep ASTERIA small because it operated at room temperature, eliminating the need for the large cooling system that a cold-operating CCD would require.

Image above: Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) CubeSat in orbit. Image Credits: NASA/JPL-Caltech.

"This mission has mostly been about learning," said Akshata Krishnamurthy, co-investigator and science data analysis co-lead for ASTERIA at JPL. "We've discovered so many things that future small satellites will be able to do better because we demonstrated the technology and capabilities first. I think we've opened doors."

ASTERIA was developed under JPL's Phaeton program, which provided early-career hires, under the guidance of experienced mentors, with the challenges of a flight project. ASTERIA is a collaboration with MIT in Cambridge; MIT's Sara Seager is principal investigator on the project. Brice Demory of the University of Bern also contributed to the new study. The project's extended missions were partially funded by the Heising-Simons Foundation. JPL is a division of Caltech in Pasadena, California.

Related links:

Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA):

Astronomical Journal:

Transiting Exoplanet Survey Satellite (TESS):

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


jeudi 4 juin 2020

Exploring new ways to see the Higgs boson

CERN - European Organization for Nuclear Research logo.

June 4, 2020

The ATLAS and CMS collaborations presented their latest results on new signatures for detecting the Higgs boson at CERN’s Large Hadron Collider

Image above: Collision events recorded by ATLAS (left) and CMS (right), used in the search for rare Higgs boson transformations (Image: CERN).

The ATLAS and CMS collaborations presented their latest results on new signatures for detecting the Higgs boson at CERN’s Large Hadron Collider. These include searches for rare transformations of the Higgs boson into a Z boson – which is a carrier of one of the fundamental forces of nature – and a second particle. Observing and studying transformations that are predicted to be rare helps advance our understanding of particle physics and could also point the way to new physics if observations differ from the predictions. The results also included searches for signs of Higgs transformations into “invisible” particles, which could shine light on potential dark-matter particles. The analyses involved nearly 140 inverse femtobarns of data, or around 10 million billion proton–proton collisions, recorded between 2015 and 2018.

The ATLAS and CMS detectors can never see a Higgs boson directly: an ephemeral particle, it transforms (or “decays”) into lighter particles almost immediately after being produced in proton–proton collisions, and the lighter particles leave telltale signatures in the detectors. However, similar signatures may be produced by other Standard-Model processes. Scientists must therefore first identify the individual pieces that match this signature and then build up enough statistical evidence to confirm that the collisions had indeed produced Higgs bosons.

When it was discovered in 2012, the Higgs boson was observed mainly in transformations into pairs of Z bosons and pairs of photons. These so-called “decay channels” have relatively clean signatures making them more easily detectable, and they have been observed at the LHC. Other transformations are predicted to occur only very rarely, or to have a less clear signature, and are therefore challenging to spot.

At LHCP, ATLAS presented the latest results of their searches for one such rare process, in which a Higgs boson transforms into a Z boson and a photon (γ). The Z thus produced, itself being unstable, transforms into pairs of leptons, either electrons or muons, leaving a signature of two leptons and a photon in the detector. Given the low probability of observing a Higgs transformation to Zγ with the data volume analysed, ATLAS was able to rule out the possibility that more than 0.55% of Higgs bosons produced in the LHC would transform into Zγ. “With this analysis,” says Karl Jakobs, spokesperson of the ATLAS collaboration, “we can show that our experimental sensitivity for this signature has now reached close to the Standard Model’s prediction.” The extracted best value for the H→Zγ signal strength, defined as the ratio of the observed to the predicted Standard-Model signal yield, is found to be 2.0+1.0−0.9.

CMS presented the results of the first search for Higgs transformations also involving a Z boson but accompanied by a ρ (rho) or φ (phi) meson. The Z boson once again transforms into pairs of leptons, while the second particle transforms into pairs of pions (ππ) in the case of the ρ and into pairs of kaons (KK) in the case of the φ. “These transformations are extremely rare,” says Roberto Carlin, spokesperson of the CMS collaboration, “and are not expected to be observed at the LHC unless physics from beyond the Standard Model is involved.” The data analysed allowed CMS to rule out that more than approximately 1.9% of Higgs bosons could transform into Zρ and more than 0.6% could transform into Zφ. While these limits are much greater than the predictions from the Standard Model, they demonstrate the ability of the detectors to make inroads in the search for physics beyond the Standard Model.

Large Hadron Collider (LHC). Animation Credit: CERN

The so-called “dark sector” includes hypothetical particles that could make up dark matter, the mysterious element that accounts for more than five times the mass of ordinary matter in the universe. Scientists believe that the Higgs boson could hold clues as to the nature of dark-matter particles, as some extensions of the Standard Model propose that a Higgs boson could transform into dark-matter particles. These particles would not interact with the ATLAS and CMS detectors, meaning they remain “invisible” to them. This would allow them to escape direct detection and manifest as “missing energy” in the collision event. At LHCP, ATLAS presented their latest upper limit – of 13% – on the probability that a Higgs boson could transform into invisible particles known as weakly interacting massive particles, or WIMPs, while CMS presented results from a new search into Higgs transformations to four leptons via at least one intermediate “dark photon”, also presenting limits on the probability of such a transformation occurring at the LHC.

The Higgs boson continues to prove invaluable in helping scientists test the Standard Model of particle physics and seek physics that may lie beyond. These are only some of the many results concerning the Higgs boson that were presented at LHCP. You can read more about them on the ATLAS and CMS websites.



This media update is part of a series related to the 2020 Large Hadron Collider Physics conference, which took place from 25 to 30 May 2020. Originally planned to take place in Paris, the conference was held entirely online due to the COVID-19 pandemic.

Technical note:

When data volumes are not high enough to claim a definite observation of a particular process, physicists can predict the limits that they expect to place on the process. In the case of Higgs transformations, these limits are based on the product of two terms: the rate at which a Higgs boson is produced in proton–proton collisions (production cross-section) and the rate at which it will undergo a particular transformation to lighter particles (branching fraction).

ATLAS expected to place an upper limit of 1.7 times the Standard Model expectation for the process involving Higgs transformations to a Z boson and a photon (H→Zγ) if such a transformation were not present; the collaboration was able to place an upper limit of 3.6 times this value, approaching the sensitivity to the Standard Model’s predictions. The CMS searches were for a much rarer process, predicted by the Standard Model to occur only once in every million Higgs transformations, and the collaboration was able to set upper limits of about 1000 times the Standard Model expectations for the H→Zρ and H→Zφ processes.


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States.

Links to the papers and notes:

ATLAS search for H→Zγ:

CMS search for H→Zρ or H→Zϕ:

ATLAS search for “invisible” transformations of the Higgs boson:

CMS search for Higgs transformations involving a dark photon:

Related links:



Large Hadron Collider (LHC):

Standard Model:

Higgs boson:

For more information about European Organization for Nuclear Research (CERN), Visit:

Image (mentioned), Animation (mentioned), Text, Credit: CERN.

Best regards,

Advanced Station Science Benefiting Humans

ISS - Expedition 63 Mission patch.

June 4, 2020

The five-member Expedition 63 crew aboard the International Space Station continues exploring how microgravity phenomena may benefit humans on and off Earth.

Commander Chris Cassidy started off Thursday working on the Electrostatic Levitation Furnace, a device that heats materials to very high temperatures and measures their thermophysical properties. The unique furnace may provide scientists insights into synthesizing and producing new materials. The veteran astronaut then spent the afternoon servicing U.S. spacesuit components ahead of a series of spacewalks planned for June.

Image above: The International Space Station’s two newest crew members, NASA astronauts (from left) Bob Behnken and Doug Hurley, are pictured having just entered the orbiting lab shortly after arriving aboard the SpaceX Crew Dragon spacecraft. Image Credit: NASA.

New NASA Flight Engineers Doug Hurley and Bob Behnken spent Thursday servicing space botany hardware and exploring bubbles in fluids. Both astronauts temporarily disassembled a plant habitat to access and replace environment control system gear. The duo also studied how bubbles affect microfluids to help produce oxygen on a spacecraft and deliver drugs though skin patches.

Roscosmos Flight Engineers Anatoly Ivanishin and Ivan Vagner, worked throughout the orbital lab on Thursday ensuring ongoing research and maintenance operations.

International Space Station (ISS). Image Credit: NASA

Ivanishin was inside the U.S. Destiny laboratory swapping fuel bottles inside the Combustion Integrated Rack to enable safe fuel and flame science. He also worked on cargo transfers inside the Progress 74 resupply ship. Vagner inspected surfaces inside the Russian portion of the space station. In the afternoon, the first-time space flyer set up a video camera to record crew activities for audiences back on Earth.

Related links:

Expedition 63:

Plant habitat:

Bubbles affect microfluids:

U.S. Destiny laboratory:

Combustion Integrated Rack:

Safe fuel and flame science:

Commercial Crew Program:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

Space Station 20th: Spacewalking History

ISS - 20 Years on the International Space Station patch.

June 4, 2020

Assembly of the International Space Station (ISS) would not have been possible without the skilled work of dozens of astronauts and cosmonauts performing intricate tasks in bulky spacesuits in the harsh environment of space. Spacewalks, or extravehicular activities (EVAs), were indispensable to the assembly of ISS and today remain important to the continued maintenance of the world class laboratory in low Earth orbit.

Above: Leonov during the world’s first EVA in March 1965.
Bellow: White during the first American EVA in June 1965.

On June 3, 1965, astronaut Edward H. White opened the hatch to the Gemini 4 capsule and, as he floated out of the cabin, became the first American to walk in space. A few weeks earlier, on March 18, Soviet cosmonaut Aleksei A. Leonov took the world’s first spacewalk as he floated out of an airlock attached to his Voskhod 2 spacecraft. Although White’s 36-minute EVA appeared effortless, later spacewalkers in the Gemini Program found accomplishing actual work quite challenging. Because NASA considered mastering spacewalking a critical task for the Apollo Moon landing program, astronauts and engineers expended much effort to learn the required skills, and by the final flight of the Gemini program astronaut Edwin E. “Buzz” Aldrin proved that EVAs could be productive. His training in an underwater environment to simulate spacewalking proved to be a game-changer and the practice has been standard ever since.

Above: Apollo 17 astronaut Harrison H. “Jack” Schmitt during an EVA on the lunar surface in 1972.
Middle: Skylab 4 astronaut Edward G. Gibson during the final EVA of the Skylab Program in 1974.
Bellow: Soviet cosmonaut Georgi M. Grechko preparing for the first EVA aboard the Salyut-6 space station in 1977.

Most spacewalks during the Apollo Program took place on the lunar surface and extended EVA durations past seven hours through upgrades to the spacesuits or Extravehicular Mobility Units (EMUs). Spacewalks conducted aboard Skylab in the mid-1970s proved the value of spacesuited astronauts to carry out repairs and maintenance of the space station – indeed, the EVA to free Skylab’s jammed solar array played a key role in saving the program. Similarly, beginning in the late 1970s, Soviet then Russian cosmonauts using ever-improved Orlan spacesuits proved the value of EVAs in inspecting, maintaining, repairing and augmenting space stations.

Above: STS-6 astronauts F. Story Musgrave (left) and Donald H. Peterson during the first Shuttle
EVA in 1983. Middle: Mir 20 crewmembers Sergei V. Avdeyev (left) and European Space Agency
astronaut Thomas A. Reiter in 1995. Bellow: STS-125 astronauts John M. Grunsfeld and Andrew J. Feustel preparing to reenter the Shuttle’s airlock after the final Hubble servicing EVA in 2009.

Spacewalks during the Space Shuttle era demonstrated that astronauts during EVAs could capture, repair and redeploy satellites, test future refueling of spacecraft and evaluate assembly techniques. From the first EVA during STS-6 in 1983 to the last non-space station related Shuttle EVA during STS-125, the final Hubble Servicing Mission in 2009, astronauts completed 52 spacewalks, 23 of them dedicated to servicing the Hubble Space Telescope in the course of five missions. Cosmonauts aboard the Mir space station made extensive use of EVAs for construction, maintenance and scientific and technology research during 79 spacewalks over the facility’s 15-year orbital lifetime. Mir also hosted the first EVA by a non-Russian crewmember, Jean-Loup Chrétien from France in 1988.

Above: Linenger during his EVA with Tsibliev outside Mir.
Bellow: Parazynski (left) and Titov during the STS-86 EVA at Mir.

One of the stated objectives of the Shuttle-Mir Program, also known as Phase 1 of ISS, was for the United States and Russia to learn to work together as the two former adversaries prepared to jointly build and operate the space station. One arena where this was clearly demonstrated was in spacewalking. As Phase 1 progressed, astronauts living and working aboard Mir became more involved in the station’s operations, including conducting EVAs. On April 29, 1997, Jerry M. Linenger became the first American astronaut to perform an EVA in a Russian Orlan spacesuit with his Mir 23 commander Vasili V. Tsibliev. C. Michael Foale and David A. Wolfe added to that experience base with their Mir Orlan EVAs later that year. Foale became the first person to perform EVAs in both the US EMU and the Russian Orlan spacesuits. On Oct. 1, 1997, Scott E. Parazynski and Vladimir G. Titov performed the first joint US-Russian EMU EVA during STS-86 while Space Shuttle Atlantis was docked to Mir. Titov was also the first non-American to conduct a Shuttle-based EVA.

Graphic representation of the number of ISS EVAs over the past 22 years.

The complex assembly of ISS would have been impossible without the skilled labors of spacewalking astronauts and cosmonauts. The cumulative experience of the EVAs conducted in the years prior to the start of ISS assembly formed a solid basis on which to build the necessary spacewalking skills. It is of interest to note that 23 years passed between Leonov’s first daring venture into open space and the first EVA at ISS, during which time 171 spacewalks were completed in low Earth orbit, on the Moon and in deep space. In the 22 years since the first ISS assembly EVA, 227 spacewalks dedicated to ISS have been accomplished plus an additional 13 during Space Shuttle missions unrelated to ISS, 4 on the Russian Mir space station and 1 by the People’s Republic of China.

Above: STS-88 astronauts Newman (left) and Ross perform the very first EVA at ISS in 1988.
Middle: STS-96 astronaut Jernigan moving the Strela Grapple Fixture adaptor. Bellow: STS-106
crewmembers Malenchenko (left) and Lu connect cables between Zarya and Zvezda during the
first joint US-Russian EVA on ISS.

From the very first assembly mission, spacewalks proved to be essential to preparing the fledgling ISS for its first occupants. Astronauts Jerry L. Ross and James H. Newman conducted the first ISS EVA on Dec. 7, 1988, during the STS-88 mission to connect electrical and data cables between the station’s first two modules, Zarya and Unity. Over the course of the first five Shuttle assembly missions, 12 crewmembers conducted 10 EVAs prior to the Expedition 1 crew taking up residency aboard the station. During STS-96, the second assembly mission in May 1999, Tamara E. “Tammy” Jernigan became the first of many women to perform an EVA at ISS. Astronaut Edward T. “Ed” Lu and cosmonaut Yuri I. Malenchenko conducted the first US-Russian EVA at ISS during the June 2000 STS-101 mission. The two connected electrical and data cables between Zarya and the newly-arrived Zvezda module. Training for that spacewalk required Russian engineers to modify the Hydrolab facility at the Gagarin Cosmonaut Training Center to accommodate the US EMUs. Similarly, American engineers adapted the Neutral Buoyancy Laboratory at Johnson Space Center to allow the Expedition 1 crew to train using both the EMU and the Russian Orlan spacesuit.

Above: Expedition 2 astronaut Helms during the longest EVA to date. Middle: STS-100 astronaut
Hadfield, the first Canadian to perform an EVA at ISS. Bellow: Expedition 2 crewmembers Voss (left) and Usachev in the hatchway to Zvezda’s Transfer Compartment preparing for the first Russian Segment EVA.

Following the arrival of Expedition 1 crewmembers William M. Shepherd, Yuri P. Gidzenko and Sergei K. Krikalev aboard ISS on Nov. 2, 2000, the pace of assembly and the number of spacewalks increased significantly. Between December 2000 and April 2003, 38 astronauts and cosmonauts completed 41 EVAs, including the first staged from ISS itself rather than from the Space Shuttle. On March 10, 2001, Expedition 2 astronauts James S. Voss and Susan J. Helms conducted a spacewalk during STS-102 that at 8 hours and 56 minutes still stands as the longest EVA in history. In April 2001, Canadian Space Agency astronaut Chris A. Hadfield became the first Canadian to conduct an EVA at ISS during STS-100, the flight that brought the Canadarm2 robotics system to the space station. On June 8, Voss joined Expedition 2 cosmonaut Yuri V. Usachev for the first Russian segment EVA, an internal spacewalk in Zvezda’s Transfer Compartment to prepare it for the arrival of a new module.

Above: STS-104 astronauts Gernhardt emerging to begin the first EVA from the ISS Quest
Joint Airlock. Middle: Expedition 3 cosmonauts Dezhurov (left) and Tyurin about to begin the
first EVA from the Pirs module. Bellow: STS-111 crewmember Perrin, the first French astronaut
to perform an EVA at ISS.

The STS-104 mission in July 2001 brought the Quest Joint Airlock to the station, providing ISS with a standalone EVA capability, with accommodations for both the US EMU and the Russian Orlan suits. Michael L. Gernhardt and James F. Reilly performed the first EVA from Quest on July 20. The Pirs module arrived at ISS on Sept. 17, providing the Russian segment with a true airlock capability. On Oct. 8, Expedition 3 cosmonauts Vladimir N. Dezhurov and Mikhail V. Tyurin staged the first EVA from Pirs. Along with American and Russian crewmembers, international partners continued to play a role in spacewalking, with Philippe Perrin becoming the first astronaut from France to perform an EVA at ISS during the STS-111 mission in June 2002.

Above: Expedition 8 Commander Foale preparing for the first “two-person” EVA.
Middle: STS-114 astronaut Noguchi performing the first EVA for JAXA at ISS.
Bellow: Expedition 13 astronaut Reiter conducting the first EVA by an ESA crewmember at ISS.

Following the Space Shuttle Columbia accident, ISS EVAs continued but only from the Russian segment with the added complication that with the resident crew size reduced to two, the pair of spacewalking crewmembers left no one inside the station to monitor its systems. Although this posed a slightly increased risk should something go wrong, these “two-person” EVAs proved essential during the Shuttle hiatus. Expedition 8 crewmembers Aleksandr Y. Kaleri and Mike Foale conducted the first such EVA on Feb. 26, 2004. Foale had prior experience with the Orlan suit as he had completed an EVA during his long-duration stay aboard Mir in 1997. The crew had to cut the EVA short due to Kaleri’s suit overheating and water droplets forming inside his helmet. The crew later identified the problem as a kink in the water line in his liquid cooling garment. The incident provided a preview of a more serious problem to occur in an EMU during an EVA more than nine years later. On the STS-114 Shuttle Return-to-Flight mission, Soichi Noguchi became the first astronaut from the Japan Aerospace Exploration Agency to conduct an EVA at ISS on July 30, 2005. The first European Space Agency astronaut to perform an ISS spacewalk was Expedition 13 crewmember Thomas A. Reiter from Germany, on Aug. 3, 2006.

Above: Closeup of the tear in the solar array. Middle: STS-120 astronaut Parazynski atop the robotic
arm and boom near the site of the tear. Bellow: Parazynski approaches the tear to effect the repair.

Although all spacewalks carry a certain amount of risk, two examples illustrate how some EVAs are riskier than others. The objectives of the STS-120 mission in October 2007 included not only delivery of the Harmony module to ISS but also the relocation of the P6 truss segment from its location atop the Z1 truss, where it had been since December 2000, to the outboard port side truss. During the overall reconfiguration of the station’s power systems earlier in 2007, the P6’s solar arrays were rolled up. After the crewmembers relocated P6 to the outboard truss, they began to unfurl the two arrays. The first array opened without incident, but with the second array nearly unfurled the astronauts noticed a tear in a small portion of the panel and immediately halted the deployment to prevent damaging it. Working with the onboard crew, mission managers devised a plan to have one of the astronauts essentially suture the tear in the panel. Appropriately enough, one of the two STS-120 spacewalkers, Scott E. Parazynski, was also a physician and he put his suturing skills to good use. Attached to a portable foot restraint, Parazynski was hoisted atop not only the station’s robotic arm but also the Shuttle’s boom normally used to inspect the Orbiter’s tiles, the impromptu arrangement providing just enough reach for Parazynski to successfully repair the torn array using a newly-designed tool dubbed “cufflinks.” After he secured five cufflinks to the damaged panel, crewmembers inside the station fully extended the array as Parazynski monitored the event.

Above: Expedition 36 astronaut Parmitano during EVA23. Bellow: Expedition 36
crewmembers Nyberg (left) and Yurchikhin assist Parmitano with removing
his EMU after his safe return to the airlock.

Luca S. Parmitano, the first astronaut representing the Italian Space Agency to conduct an EVA at ISS, and his fellow Expedition 36 crewmember Christopher J. Cassidy began US EVA23, their second EVA together, on July 16, 2013, without incident. Forty-four minutes into the EVA, as the two crewmembers worked on their individual tasks at different locations on ISS, Parmitano reported feeling water at the back of his head. Mission Control advised them to halt their activities as they devised a plan of action. Cassidy came to Parmitano’s side to assess the situation, at first believing that a leaking drink bag inside the suit was the source of the water. But as Parmitano indicated that the amount of water was increasing, Mission Control advised them to terminate the EVA, directing Parmitano to head back to the airlock and Cassidy to clean up any tools and then follow his crewmate back to the airlock. As Parmitano began translating back toward the airlock, the water continued to increase, migrating from the back of his head, filling his ears so he had difficulty hearing communications and eventually obscuring his vision and interfering with breathing. He made his way back to the airlock mostly by memory and feel, and after Cassidy joined him inside they repressurized the module. Expedition 36 crewmates Karen L. Nyberg and Fyodor N. Yurchikhin helped Parmitano quickly remove his helmet and towel off the estimated 1 to 1.5 liters of water. Later investigation indicated that contamination on a filter caused blockage in the suit’s water separator. Although Parmitano faced a potentially life-threatening situation, his calm response along with quick decisions by the team in Mission Control resolved the crisis successfully. He later joked during an in-flight press conference that he “experience what it was like to be a goldfish in a fishbowl from the point of view of the goldfish.”

Above: Preparing for the first all-woman EVA are Expedition 61 astronauts Meir (left)
and Koch. Bellow: The latest EVA on ISS in January 2020, performed by Expedition 61
astronauts Morgan (left) and Parmitano.

The Expedition 61 crew completed a record nine EVAs between Oct. 6, 2019, and Jan. 25, 2020. Five involved tasks to replace batteries on the P6 truss segment and three to repair the Alpha Magnetic Spectrometer (AMS), a physics experiment not originally designed for on-orbit repairs. Of note, Christina Koch and Jessica U. Meir conducted the third battery-replacement EVA on Oct. 18, the first time all-female spacewalk in history. The pair completed two more EVAs in January 2020. Their fellow crewmembers, Andrew J. “Drew” Morgan and Luca Parmitano, completed the most recent EVA to date, the final spacewalk to repair AMS.

Related articles:

Space Station 20th: Commercial Cargo and Crew

Space Station 20th: Music on ISS

Space Station 20th – Space Flight Participants

Space Station 20th: Six Months Until Expedition 1

Space Station 20th – Women and the Space Station

Space Station 20th: Long-duration Missions

NASA Counts Down to Twenty Years of Continuous Human Presence on International Space Station

20 memorable moments from the International Space Station

Related links:

International Space Station (ISS):

Images, Text, Credits: NASA/Kelli Mars/JSC/John Uri/ESA/JAXA/CSA-ASC/ROSCOSMOS.