vendredi 11 octobre 2019

Second of Five Power Upgrade Spacewalks Wraps Up

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

October 11, 2019

Expedition 61 Flight Engineers Christina Koch and Andrew Morgan of NASA concluded their spacewalk at the International Space Station at 2:23 p.m. EDT. During six-hour and 45-minute spacewalk, the two NASA astronauts continued the replacement of nickel-hydrogen batteries with newer, more powerful lithium-ion batteries on the far end of the station’s port truss.

Astronauts also were able to accomplish several get-ahead tasks setting up for the next spacewalk.

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

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

October 11, 2019 spacewalk. Image Credit: NASA TV

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

Space station crew members have conducted 220 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 57 days 13 hours and 12 minutes working outside the station.

Related links:

Expedition 61:

Alpha Magnetic Spectrometer (AMS):

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Norah Moran.

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Space Station Science Highlights: Week of October 7, 2019

ISS - Expedition 61 Mission patch.

Oct. 11, 2019

While it was a week full of spacewalks, the crew aboard the International Space Station fit in some science during the week of Oct. 7. In addition to prepping for a series of battery Extravehicular Activities (EVAs), research conducted included collecting air quality samples, watering veggies and recharging free-flying robot assistants. Research like this conducted aboard the space station is a crucial stepping stone for Artemis, NASA’s plans to go forward to the Moon and on to Mars.

Image above: NASA astronaut Andrew Morgan takes an out-of-this-world "space-selfie" during a spacewalk to upgrade space station power systems on the Port-6 (P6) truss structure. He and fellow NASA astronaut Christina Koch (out of frame) worked for about seven hours to begin the latest round of upgrading the station's large nickel-hydrogen batteries with newer, more powerful lithium-ion batteries. Image Credit: NASA.

Here are details on some of the science conducted on the orbiting laboratory during the week:

Checking out the air

This past week, the crew helped collect samples for the Spacecraft Atmosphere Monitor (S.A.M.). One of the most important conditions associated with crew health during spaceflight is air quality. Currently, atmosphere quality aboard the space station is assessed by periodic sampling and ground-based analysis using sophisticated instruments. Since samples cannot be returned to Earth during future exploration missions, a complement of smaller and more reliable instruments such as S.A.M. becomes essential to monitor the crew environment.

It’s planting season

Image above: NASA astronaut Christina Koch checks progress on small plant pillows for the Veg-04B investigation. Veg-04B focuses on the effects of light quality and fertilizer on the leafy Mizuna mustard green crop, microbial food safety, nutritional value and the taste acceptability by the crew. Image Credit: NASA.

Watering crops on the space station is a bit different than on Earth. Rather than pouring water onto soil, the crew injected water to small plant pillows that provide needed water to the growing veggies. This is part of Veg-04B, one piece of a phased research project attempting to address the need for a continuous fresh-food production system in space to supplement typical pre-packaged foods for astronauts. Veg-04B focuses on the effects of light quality and fertilizer on the leafy Mizuna mustard green crop, microbial food safety, nutritional value and the taste acceptability by the crew.

Image above: NASA astronaut Andrew Morgan reviews procedures the day before the EVA that took place on Oct. 6 to upgrade the space station’s batteries. Image Credit: NASA.

Getting charged up

The free-flying robot facility known as Astrobee got its batteries charged up this week. The facility is designed to help scientists and engineers develop and test technologies that can assist astronauts with routine chores and give ground controllers additional eyes and ears on the space station. The autonomous robots, powered by fans and vision-based navigation, perform crew monitoring and sampling and logistics management. The robots accommodate up to three investigations.

Animation above: NASA astronaut Christina Koch spins a Grab Sample Container, a device that is used for collecting environmental samples for the Spacecraft Atmosphere Monitor.
Image Credit: NASA.

Other investigations on which the crew performed work:

- The brain is capable of self-regulating blood flow even when the heart and blood vessels cannot maintain an ideal blood pressure. The Cerebral Autoregulation investigation tests whether this self-regulation improves in the microgravity environment of space.

- The Food Physiology experiment is designed to characterize the key effects of an enhanced spaceflight diet on immune function, the gut microbiome and nutritional status indicators.

- Actiwatch is a nonintrusive, wearable monitor that analyzes a crew member’s circadian rhythms, sleep-wake patterns and activity.

- ISS Ham Radio provides students, teachers, parents and other members of the community an opportunity to communicate directly with astronauts using Ham radio units.

- 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.

- The Microgravity Crystals investigation crystallizes a membrane protein that is integral to tumor growth and cancer survival. Results may support development of cancer treatments that target the protein more effectively and with fewer side effects.

- BEST studies the use of DNA sequencing to identify unknown microbial organisms and improve understanding of how humans, plants and microbes adapt to living in space.

Related links:

Expedition 61:


Spacecraft Atmosphere Monitor (S.A.M.):



ISS National Lab:

Spot the Station:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Michael Johnson/John Love, Lead Increment Scientist Expedition 61.

Best regards,

Celebrating a Mission That Changed How We Use Radar

NASA - STS-59 Mission patch.

October 11, 2019

Oct. 11, 2019, marks the 25th anniversary of the end of a space mission that transformed the way we use radar to observe large-scale environmental processes on our home planet. The Spaceborne Imaging Radar-C and X-Band Synthetic Aperture Radar (SIR-C/X-SAR) mission made available to people worldwide the scientific data used to this day to inform decisions to slow and mitigate climate change.

The SIR-C instrument, built by NASA'S Jet Propulsion Laborator in Pasadena, California, and the X-SAR instrument, built by the German Aerospace Center (DLR), constituted the most advanced imaging radar system ever used in air or space. During hundreds of orbits on two flights aboard the Space Shuttle Endeavour, in April and October 1994, the radar system made multiple passes over 19 "supersites" - areas of scientific interest in such locations as the Sahara, Brazil, the Alps and the Gulf Stream. It also imaged events occurring during the flights, such as as a volcano erupting in Russia.

Image above: With SIR-C/X-SAR instruments mounted in the cargo bay atop the shuttle, the Endeavour crew flew upside down, using precise navigation, the hinge on the X-band antenna and "electronic steering" in the C- and L-band antennas to point the radars at "supersites" of scientific interest on Earth. Image Credits: NASA/JPL-Caltech.

"The many innovationsof SIR-C/X-SAR have been used in virtually every air- and spaceborne radar mission since, starting with NASA's Shuttle Radar Topography Mission, which mapped 80% of the Earth in 2000," said Tony Freeman, now manager of JPL's Innovation Foundry, who led end-to-end calibration of SIR-C. "DLR's TerraSAR-X and TanDEM-X missions have since filled remaining gaps."

Radar imaging of Earth has never been the same since SIR-C/X-SAR's demonstration of what's known as simultaneous multifrequency, fully polarized, repeat-pass interferometric SAR. To unpack that sizable trunk of terminology, let's start with "synthetic aperture radar": Since the late 1970s, NASA has been imaging Earth with radar - in darkness, under cloud cover or vegetation, even underground - using the movements of a host airplane or spacecraft to "synthesize" an "aperture" much larger than the antenna itself. The larger the aperture, the greater the image resolution. Indeed, SIR-C's predecessors, SIR-A and SIR-B, were synthetic aperture radar missions.

However, unlike SIR-C/X-SAR, neither predecessor made radar observations simultaneously in three frequencies - C-, L- and X-band - using three adjacent antennas combined into a massive, 12-by-4-meter, 11.5-ton structure. That advance, analogous to the leap from black-and-white to color film, allowed the mission to collect data in different scales, providing a crisp snapshot of each targeted feature, unmuddied by possible changes over time.

Blazing a Trail

In addition to multiple frequencies, some observations were made in multiple "polarizations." Radio frequency waves can be either horizontal (in a wavy plane parallel to the ground) or vertical (in a plane perpendicular to the ground). The C- and L-band antennas could send and receive waves of both horizontal and vertical polarization. Using this "fully polarized" data, scientists can separate out the scattering of radar waves to distinguish, for example, vegetated from unvegetated terrain.

SIR-C/X-SAR wanted to capture changes over time; that's why it flew on shuttle flights six months apart. To observe the same supersites during both flights and to make consistent daily passes over them, the shuttle crew used sophisticated algorithms to navigate the spacecraft in precise orbits as close as 10 meters apart. And they did this flying upside down, since the cargo bay holding the instruments was on top of the shuttle. While the X-band antenna had a hinge, the C- and L-band antennas were fixed at a particular angle, but they had "electronic steering" that allowed them to "see" to either side of what was right in front of them.

Those repeated, slightly offset passes over the same terrain were essential for the data-processing technique of interferometry. Combining views, interferometry creates detailed, 3D topographical images of a target at the moment of simultaneous observations. And it can reveal even minute changes in the target between successive observations - like the gradual creep of an earthquake fault or the movement of an ice sheet.

Image above: These ancient river channels, invisible to the human eye beneath the deep, dry sand of the Sahara Desert, were revealed for the first time by SIR-C/X-SAR instruments during their second shuttle flight in October 1994. Image Credits: NASA/JPL-Caltech.

The SIR-C/X-SAR dataset proved immediately useful, revealing, for instance, ancient riverbeds beneath the Sahara - an artifact of preindustrial climate change - and remains in high demand.

"SIR-C/X-SAR was the path opener for multiple U.S. and international missions that followed," said Charles Elachi, the mission's principal investigator before he became director of JPL. "Imaging of subsurface river channels in the Eastern Sahara enabled new understanding of the environmental history of that and other arid regions. Using multiple frequencies enabled for the first time 'color' radar images that have been used extensively to map vegetation and forests and extract their vegetation content. Using repeat-pass interferometry enabled us for the first time to map surface motion at the centimeter level. This technique is now commonly used to map motions resulting from earthquakes, volcanic eruptions and other natural disasters."

Freeman agrees: "SIR-C/X-SAR was innovative on so many fronts: We knew what we were working on was something special, but we didn't know at the time how many firsts the mission would rack up".

The NASA Image and Video Library makes mission data available to researchers worldwide. The University of Michigan hosts a search tool for accessing its own vast SIR-C/X-SAR database. And in its MapReady tool the University of Alaska Satellite Facility has processed the data for compatibility with multiple computer platforms.

Missions using technologies pioneered by SIR-C/X-SAR have revealed changes in Earth's natural features over increasingly meaningful periods, informing long-term policy to prevent and mitigate climate change. At the same time, they reveal the immediate effects of natural disasters rapidly enough to advise first responders.

Image above: Using the technique of interferometric SAR first demonstrated on SIR-C/X-SAR, four international space agencies cooperated to combine many years' worth of radar observations over the Greenland ice sheet to map its depth and accelerating speed of loss. Image Credits: Courtesy of NASA/GSFC/Jefferson Beck.

SIR-C/X-SAR was a collaboration of NASA, DLR and the Italian Space Agency (ASI), which contributed to the ground segment for X-SAR observations. JPL managed the mission for NASA. DLR was responsible for calibration, operations and data processing for X-SAR.

Related links:

NASA Image and Video Library:


Images (mentioned), Text, Credits: NASA/JPL/Matthew Segal.


Alexei Leonov, the first spacewalker is dead

Rest In Peace.

Oct. 11, 2019

Alexei Leonov, released in space in 1965, died on Friday at the age of 85.

Cosmonaut Alexei Leonov, the first spacewalker

Soviet cosmonaut Alexei Leonov died Friday at the age of 85. He was the first man to make a spacewalk in 1965 and, ten years later, commanded the first joint space mission of the USSR and the United States.

On March 19, 1965, Alexei Leonov made his first outing from his ship Voskhod-2 in the open space, earning him the nickname of first "pedestrian of space". He had cautiously departed two to three meters from the ship, finding the operation very painful.

First spacewalk, Alexey Leonov, March 18, 1965

Blinded by the Sun, despite his golden visor, he was held securely by a cable at the airlock of his ship. "Here, I try," he said, leaving. The operation lasted twenty minutes, twelve minutes entirely outside the Voskhod.

Long illness

The cosmonaut was also the Soviet side commander of the Apollo-Soyuz mission in 1975, the first joint between the two rivals of the Cold War and the space race. This mission marked the beginning of a technological cooperation that continues today.

The cosmonaut was also a close friend of his compatriot Yuri Gagarin, the first man in space. When he died in a plane crash on March 27, 1968 near Moscow, he was one of the first on the scene.

Alexei Leonov died "after a long illness," his collaborator Natalia Filimonova told AFP. His funeral is scheduled for Tuesday in Moscow, announced the Cosmonaut Preparation Center.

Alexey Leonov - Wikipedia:

Image, Video, Text, Credits: ROSCOSMOS/AFP/ Aerospace/Roland Berga.


Northrop Grumman Pegasus XL launches ICON

NASA - Ionospheric Connection Explorer (ICON) logo.

11 oct. 2019

L-1011 Stargazer aircraft and Pegasus XL rocket

A Pegasus XL rocket launched NASA’s Ionospheric Connection Explorer (ICON) on 11 October 2019, at 02:00 UTC. The Northrop Grumman L-1011 Stargazer aircraft took off from the Skid Strip runway at Cape Canaveral Air Force Station in Florida. ICON will explore the ionosphere, the dynamic region where Earth meets space.

Pegasus XL launches ICON (Ionospheric Connection Explorer)

ICON will study the ionosphere, a region of Earth’s upper atmosphere where terrestrial weather meets space weather. Disturbances in the ionosphere triggered by solar storms or weather activity in the lower atmosphere can cause disturbances in GPS navigation and radio transmissions.

Ionospheric Connection Explorer (ICON)

The mission’s staging point was changed from Kwajalein Atoll to Cape Canaveral Air Force Station in mid-2018. Delayed from June 15, Nov. 14, and Dec. 8, 2017. Delayed from June 14, Sept. 24, Oct. 6, Oct. 26 and Nov. 3. Scrubbed on Nov. 7. Delayed from 1st Quarter 2019. Delayed from Oct. 9 by poor weather.

NASA’s Ionospheric Connection Explorer (ICON):

Images, Video, Text, Credits: NASA/Randy Beaudoin/Ben Smegelsky/USAF 30th SCS/Anthony Vauclin/Northrop Grumman/SciNews/ Aerospace/Roland Berga.


An American astronaut decorated by Vladimir Putin

Order of  Lenin medal.

Oct. 11, 2019

Rescued from the Soyuz rocket accident in October 2018, astronaut Nick Hague has received from the Russian president a prestigious distinction for his courage.

Soyuz MS-10 launch failure

Russian President Vladimir Putin has awarded the Order of Courage, one of the highest honors of the country, to an American astronaut. He had survived a year ago the failed takeoff of a Soyuz rocket.

According to a presidential decree published on Tuesday, the American Nick Hague, 44, is rewarded for "his courage and his high degree of professionalism" in perilous conditions during the launch at the Russian cosmodrome of Baikonur, located in Kazakhstan.

On October 11, 2018, the "Soyuz" rocket in which Nick Hague had sailed and the Russian Alexey Ovchinin had disintegrated minutes after taking off for the International Space Station (ISS), an unprecedented accident for the Russian space program since the end of the USSR.

After being successfully ejected by the automatic rescue system, the two men were released unscathed despite the very strong pressure. "It was a quick flight," commented Alexei Ovchinin, laconic, moments after the start of the incident. According to NASA, "launcher failure" occurred after 119 seconds of travel, while the rocket was launched at over 7500 km / h.

In March, they returned successfully to the ISS, where they returned last week after a six-month mission. It was the first space stay for Nick Hague, and the second for Alexey Ovchinin.

Considered one of the highest Russian distinctions, the Order of Courage is often awarded posthumously.

The International Space Station is one of the latest examples of active cooperation between Russia and the United States in a context of unprecedented tensions since the Cold War.

Related articles:

Crew in Good Condition After Booster Failure

Soyuz MS-10 - Emergency landing after a failure

Images, Video, Text, Credits: ATS / NASA / ROSCOSMOS / SciNews / Aerospace / Roland Berga.

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ILS - Proton-M launches EUTELSAT 5 West B & MEV-1

ILS - Proton-M / EUTELSAT 5 West B & MEV-1 poster.

Oct. 11, 2019

Proton-M carrying EUTELSAT 5 West B & MEV-1 lift off

An International Launch Services (ILS) Proton-M launch vehicle, with a Briz-M upper stage (Breeze M), launched the EUTELSAT 5 West B communications satellite and Mission Extension Vehicle-1 (MEV-1) from the Baikonur Cosmodrome in Kazakhstan, on 9 October 2019, at 10:17 UTC (16:17 local time). EUTELSAT 5 West B (2864 kg)  is a Ku-band satellite to be located at 5° West.

Proton-M launches EUTELSAT 5 West B & MEV-1

Build by Northrop Grumman, MEV-1 (2326 kg) will provide satellite life-extension service by docking to the client’s vehicles in geosynchronous orbit to provide attitude and orbit control. MEV-1 will extend the life of the Intelsat 901 satellite for five years.

Eutelsat 5 West B

Both spacecraft are built by Northrop Grumman Innovation Systems, formerly known as Orbital ATK. Eutelsat 5 West B will join Eutelsat’s communications fleet in geostationary orbit, replacing the Eutelsat 5 West A spacecraft providing digital and television services primarily in the French, Italian and Algerian markets.


The MEV 1 spacecraft is the first in a series of satellite servicing vehicles for SpaceLogistics, a subsidiary of Northrop Grumman Innovation Systems. MEV 1 will dock with the Intelsat 901 communications satellite and provide propulsion and attitude control functions to extend the spacecraft’s mission.

Related links:

International Launch Services (ILS):


Images, Video, Text, Credits: ILS/SciNews/ Aerospace/Roland Berga.


jeudi 10 octobre 2019

Space Biology, Human Research Day Before Spacewalk

ISS - Expedition 61 Mission patch.

October 10, 2019

Two astronauts will suit up Friday morning for the second spacewalk in a series of five this month to upgrade International Space Station power systems. In the meantime, the duo and the rest of the Expedition 61 crew are staying on top of ongoing microgravity research today aboard the orbiting lab.

NASA Flight Engineers Andrew Morgan and Christina Koch split their time today between researching space biology and preparing for tomorrow’s spacewalk. Morgan observed and photographed protein crystals in a microscope to support cancer research. Koch explored sequencing the DNA of microbes living on the station.

Image above: NASA astronauts Andrew Morgan (left) and Christina Koch (right) are suited up in U.S. spacesuits inside the Quest airlock for the first of five planned spacewalks that took place on Oct. 6, 2019. Image Credit: NASA.

The duo also worked inside the Quest airlock to ready their spacesuits, tools and tethers before they exit into the vacuum of space Friday at 7:50 a.m. EDT. They will continue swapping out the station’s large nickel-hydrogen batteries with newer, more powerful lithium-ion batteries. NASA TV begins its live coverage at 6:30 a.m.

Commander Luca Parmitano and Flight Engineer Jessica Meir set up an exercise cycle for an aerobic fitness test today. Meir strapped herself on the bike while attached to a variety of sensors for an hour-and-a-half exercise session. Flight surgeons use these evaluations to determine an astronaut’s physiological health before, during and after a flight. She also studied how blood flow to the brain adjusts in microgravity.

International Space Station (ISS). Animation Credit: NASA

Cosmonauts Alexander Skvortsov and Oleg Skripochka continued testing a unique negative pressure suit for its ability to reverse the space-caused upward flow of fluids such as blood in astronaut’s bodies. The veteran station pair also worked on a variety of Russian life support and communications systems.

Related links:

Expedition 61:


Cancer research:

sequencing the DNA:

Quest airlock:


Exercise cycle:

Blood flow to the brain:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Catherine Williams.

Best regards,

Milky Way Raids Intergalactic 'Bank Accounts,' Hubble Study Finds

NASA - Hubble Space Telescope patch.

Oct. 10, 2019

Our Milky Way is a frugal galaxy. Supernovas and violent stellar winds blow gas out of the galactic disk, but that gas falls back onto the galaxy to form new generations of stars. In an ambitious effort to conduct a full accounting of this recycling process, astronomers were surprised to find a surplus of incoming gas.

"We expected to find the Milky Way's books balanced, with an equilibrium of gas inflow and outflow, but 10 years of Hubble ultraviolet data has shown there is more coming in than going out," said astronomer Andrew Fox of the Space Telescope Science Institute, Baltimore, Maryland, lead author of the study to be published in The Astrophysical Journal.

Fox said that, for now, the source of the excess inflowing gas remains a mystery.

Image above: This illustration envisions the Milky Way galaxy's gas recycling above and below its stellar disk. Hubble observes the invisible gas clouds rising and falling with its sensitive Cosmic Origins Spectrograph (COS) instrument. The spectroscopic signature of the light from background quasars shining through the clouds gives information about their motion. Quasar light is redshifted in clouds shooting up and away from the galactic plane, while quasar light passing through gas falling back down appears blueshifted. This differentiation allows Hubble to conduct an accurate audit of the outflowing and inflowing gas in the Milky Way's busy halo — revealing an unexpected and so-far unexplained surplus of inflowing gas. Image Credits: NASA, ESA and D. Player (STScI).

One possible explanation is that new gas could be coming from the intergalactic medium. But Fox suspects the Milky Way is also raiding the gas "bank accounts" of its small satellite galaxies, using its considerably greater gravitational pull to siphon away their resources. Additionally, this survey, while galaxy-wide, looked only at cool gas, and hotter gas could play a role, too.

The new study reports the best measurements yet for how fast gas flows in and out of the Milky Way. Prior to this study, astronomers knew that the galactic gas reserves are replenished by inflow and depleted by outflow, but they did not know the relative amounts of gas coming in compared to going out. The balance between these two processes is important because it regulates the formation of new generations of stars and planets.

Astronomers accomplished this survey by collecting archival observations from Hubble’s Cosmic Origins Spectrograph (COS), which was installed on the telescope by astronauts in 2009 during its last servicing mission. Researchers combed through the Hubble archives, analyzing 200 past ultraviolet observations of the diffuse halo that surrounds the disk of our galaxy. The decade's worth of detailed ultraviolet data provided an unprecedented look at gas flow across the galaxy and allowed for the first galaxy-wide inventory. The gas clouds of the galactic halo are only detectable in ultraviolet light, and Hubble is specialized to collect detailed data about the ultraviolet universe.

"The original Hubble COS observations were taken to study the universe far beyond our galaxy, but we went back to them and analyzed the Milky Way gas in the foreground. It's a credit to the Hubble archive that we can use the same observations to study both the near and the more distant universe. Hubble's resolution allows us to simultaneously study local and remote celestial objects," noted Rongmon Bordoloi of North Carolina State University in Raleigh, North Carolina, a co-author on the paper.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

Because the galaxy's gas clouds are invisible, Fox's team used light from background quasars to detect these clouds and their motion. Quasars, the cores of active galaxies powered by well-fed black holes, shine like brilliant beacons across billions of light-years. When the quasar's light reaches the Milky Way, it passes through the invisible clouds.

The gas in the clouds absorbs certain frequencies of light, leaving telltale fingerprints in the quasar light. Fox singled out the fingerprint of silicon and used it to trace the gas around the Milky Way. Outflowing and inflowing gas clouds were distinguished by the Doppler shift of the light passing through them — approaching clouds are bluer, and receding clouds are redder.

Currently, the Milky Way is the only galaxy for which we have enough data to provide such a full accounting of gas inflow and outflow.

"Studying our own galaxy in detail provides the basis for understanding galaxies across the universe, and we have realized that our galaxy is more complicated than we imagined," said Philipp Richter of the University of Potsdam in Germany, another co-author on the study.

Future studies will explore the source of the inflowing gas surplus, as well as whether other large galaxies behave similarly. Fox noted that there are now enough COS observations to conduct an audit of the Andromeda galaxy (M31), the closest large galaxy to the Milky Way.

The Hubble Space Telescope is a project of international cooperation between ESA (the European Space Agency) and NASA. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

Related links:

The Astrophysical Journal:


Hubble Space Telescope (HST):

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center/Claire Andreoli/Space Telescope Science Institute/Leah Ramsay/Ray Villard/Andrew Fox.

Best regards,

Pressure Runs High at Edge of Solar System

NASA - Voyager 1 & 2 Mission patch.

Oct. 10, 2019

Out at the boundary of our solar system, pressure runs high. This pressure, the force plasma, magnetic fields and particles like ions, cosmic rays and electrons exert on one another when they flow and collide, was recently measured by scientists in totality for the first time — and it was found to be greater than expected.

Voyager probe in deep space. Animation Credits: NASA/JPL

Using observations of galactic cosmic rays — a type of highly energetic particle — from NASA’s Voyager spacecraft scientists calculated the total pressure from particles in the outer region of the solar system, known as the heliosheath. At nearly 9 billion miles away, this region is hard to study. But the unique positioning of the Voyager spacecraft and the opportune timing of a solar event made measurements of the heliosheath possible. And the results are helping scientists understand how the Sun interacts with its surroundings. 

“In adding up the pieces known from previous studies, we found our new value is still larger than what’s been measured so far,” said Jamie Rankin, lead author on the new study and astronomer at Princeton University in New Jersey. “It says that there are some other parts to the pressure that aren’t being considered right now that could contribute.”

On Earth we have air pressure, created by air molecules drawn down by gravity. In space there’s also a pressure created by particles like ions and electrons. These particles, heated and accelerated by the Sun create a giant balloon known as the heliosphere extending millions of miles out past Pluto. The edge of this region, where the Sun’s influence is overcome by the pressures of particles from other stars and interstellar space, is where the Sun’s magnetic influence ends.  (Its gravitational influence extends much farther, so the solar system itself extends farther, as well).

Image above: An illustration depicting the layers of the heliosphere. Image Credits: NASA/IBEX/Adler Planetarium.

In order to measure the pressure in the heliosheath, the scientists used the Voyager spacecraft, which have been travelling steadily out of the solar system since 1977. At the time of the observations, Voyager 1 was already outside of the heliosphere in interstellar space, while Voyager 2 still remained in the heliosheath.

“There was really unique timing for this event because we saw it right after Voyager 1 crossed into the local interstellar space,” Rankin said. “And while this is the first event that Voyager saw, there are more in the data that we can continue to look at to see how things in the heliosheath and interstellar space are changing over time.”

The scientists used an event known as a global merged interaction region, which is caused by activity on the Sun. The Sun periodically flares up and releases enormous bursts of particles, like in coronal mass ejections. As a series of these events travel out into space, they can merge into a giant front, creating a wave of plasma pushed by magnetic fields.

Image above: The Voyager spacecraft, one in the heliosheath and the other just beyond in interstellar space, took measurements as a solar even known as a global merged interaction region passed by each spacecraft four months apart. These measurements allowed scientists to calculate the total pressure in the heliosheath, as well as the speed of sound in the region. Image Credits: NASA's Goddard Space Flight Center/Mary Pat Hrybyk-Keith.

When one such wave reached the heliosheath in 2012, it was spotted by Voyager 2. The wave caused the number of galactic cosmic rays to temporarily decrease. Four months later, the scientists saw a similar decrease in observations from Voyager 1, just across the solar system’s boundary in interstellar space.

Knowing the distance between the spacecraft allowed them to calculate the pressure in the heliosheath as well as the speed of sound. In the heliosheath sound travels at around 300 kilometers per second — a thousand times faster than it moves through air.

The scientists noted that the change in galactic cosmic rays wasn’t exactly identical at both spacecraft. At Voyager 2 inside the heliosheath, the number of cosmic rays decreased in all directions around the spacecraft. But at Voyager 1, outside the solar system, only the galactic cosmic rays that were traveling perpendicular to the magnetic field in the region decreased. This asymmetry suggests that something happens as the wave transmits across the solar system’s boundary.

“Trying to understand why the change in the cosmic rays is different inside and outside of the heliosheath remains an open question,” Rankin said.

Studying the pressure and sound speeds in this region at the boundary of the solar system can help scientists understand how the Sun influences interstellar space. This not only informs us about our own solar system, but also about the dynamics around other stars and planetary systems.

Related Links:

Learn more about NASA’s IBEX Mission:

Learn more about NASA’s Voyager Mission:

As the Solar Wind Blows, the Heliosphere Balloons:

Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Mara Johnson-Groh.


Luca powers up for a spacewalk

ESA - Beyond Mission patch.

10 October 2019

European Space Agency (ESA) astronaut Luca Parmitano is preparing to step out into space for his first spacewalk of the Beyond mission.

ESA astronaut Luca Parmitano assists spacewalkers in the Quest airlock

Scheduled for 25 October, he will work with NASA astronaut Jessica Meir to replace nickel hydrogen batteries with newer lithium ion batteries and install battery adapter plates on the Space Station’s Port-6 truss structure.

This is a process fellow ESA astronaut Thomas Pesquet knows well, having replaced batteries on another power channel during his Proxima mission. We asked him to tell us more about the task and how the crew will prepare.

The lead-up

Known to the crew as an EVA (Extravehicular Activity), each spacewalk is planned up to a year in advance.

Thomas Pesquet spacewalk test

On Station, preparation begins around two weeks ahead, with a set of procedures called the “Road to EVA”.

“Preparing for a spacewalk will make up 2-3 hours of your schedule every day during this time,” Thomas explains. “The crew often carry out prep in their personal time as well.” 

The big day

Live coverage of Luca and Jessica’s spacewalk starts on NASA TV at 10:30 GMT (12:30 CEST), but the crew will begin their preparation around 6:00. And there is to be no showering, shaving, or applying deodorant for at least a day in advance, as any remnants of these products could mix with the pure oxygen inside the suit and pose a fire risk

Astronauts wear a liquid cooling garment underneath their spacesuit. This is connected to the water system that keeps them cool, or warm, by circulating water around their body. They also don a medical monitor and put a dosimeter in their pocket to measure radiation before entering the hatch.

EMU spacesuit

Thomas describes the process inside the airlock as “like scuba diving in reverse”, as astronauts breathe in a controlled way to rid their blood of nitrogen and adjust to lower pressure.

A third crew member, known as the Intravehicular (IV) crew member, is also isolated in the airlock, before it goes to vacuum. This person helps the astronauts with their oxygen masks and into their spacesuits, while making sure everything is checked, tethered and ready for a safe and successful sortie.

It is a role Luca will play in the two spacewalks before his, on 15 and 21 October.

Out in space

Before exiting the airlock, Thomas says, extreme focus is the overriding feeling. 

“Everybody’s watching, so many people have been involved in the preparation, and the risks are so much higher when you’re outside the Space Station,” he explains. “The only thing you can’t really prepare for are the day/night cycles.

“During the night, you only have your helmet light, so you can’t really see anything except what you’re working on. And because you’re working in all body orientations, it’s easy to get disoriented. But you know you can always follow your tether back towards the hatch.”

Luca Parmitano training at NASA’s Johnson Space Center

After exiting the airlock, Thomas says one astronaut will prepare the worksite while the other breaks torque on the pre-positioned adapter plates. Each astronaut will then work to install the adapter plates, needed to replace two older batteries with one new one.

The spacewalk on 25 October is the one of five scheduled for October. Even more are expected in November as Luca ventures out again with the complex task of repairing and enhancing dark matter hunter AMS-02 – a structure never designed to be maintained in orbit.

Related links:

Truss structure:


Human and Robotic Exploration:

Beyond mission brochure English:

International Space Station (ISS):

Images, Text, Credits: ESA/S. Corvaja/NASA.

Best regards,

Successful Ocean-Monitoring Satellite Mission Ends

NASA & CNES - Jason-2 Mission patch.

October 10, 2019

The Jason-2/Ocean Surface Topography Mission (OSTM), the third in a U.S.-European series of satellite missions designed to measure sea surface height, successfully ended its science mission on Oct. 1. NASA and its mission partners made the decision to end the mission after detecting deterioration in the spacecraft's power system.

Image above: The Jason-2/OSTM satellite provided insights into ocean currents and sea level rise with tangible benefits to marine forecasting, meteorology and understanding of climate change. These observations are being continued by its successor, Jason-3. Image Credits: NASA/JPL-Caltech.

Jason-2/OSTM, a joint NASA mission with the French space agency Centre National d'Etudes Spatiales (CNES), the National Oceanic and Atmospheric Administration (NOAA), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), launched in June 2008. The mission extended the long-term record of sea surface height measurements started by the NASA-CNES TOPEX/Poseidon and Jason-1 missions. Jason-2/OSTM's 11-year lifetime well exceeded its three-year design life. These measurements are being continued by its successor, Jason-3, launched in 2016.

"Today we celebrate the end of this resoundingly successful international mission," said Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. "Jason-2/OSTM has provided unique insight into ocean currents and sea level rise with tangible benefits to marine forecasting, meteorology and our understanding of climate change."

Since its launch, Jason-2/OSTM charted nearly 2 inches (5 centimeters) of global sea level rise, a critical measure of climate change. The mission has also resulted in the distribution of over a million data products and the publication of more than 2,100 science papers.

Image above: Jason-2/OSTM contributed to a long-term record of global sea levels. This image shows areas in the Pacific Ocean where sea levels were lower (blues) or higher (reds) than normal during the first week of January 2018. Image Credits: NASA/JPL-Caltech.

"Jason-2/OSTM was a high point of operational satellite oceanography as the first Jason mission to formally include EUMETSAT and NOAA as partners," said Steve Volz, assistant administrator of NOAA's Satellite and Information Service. "During its 11-year run, Jason-2/OSTM helped improve NOAA's hurricane intensity forecasts and provided important observations of marine winds and waves and in doing so has anchored these essential ocean altimetry observations in NOAA's operational observing system requirements."

With the recent degradation of the spacecraft's power system, mission partners decided to end the mission to decrease risks to other satellites and future altimetry missions, and to comply with French space law. Final decommissioning operations for Jason-2/OSTM are scheduled to be completed by CNES on Oct. 10.

"With the involvement of EUMETSAT and NOAA, Jason-2 brought high precision monitoring of ocean surface topography and mean sea level to operational status," said Alain Ratier, EUMETSAT's director general. "Its 11-year lifetime in orbit was rewarding for the four program partners and the ocean and climate user community."

Image above: Global sea level has shown a steady rise since the early 1990s to present as measured by Jason-2/OSTM and its predecessors and successor from the early 1990s to present day. Image Credits: NASA/JPL-Caltech.

Jason-2/OSTM's mission might have ended earlier if not for the ingenuity of its mission teams. In July 2017, the degradation of critical onboard components and control systems required that Jason-2/OSTM move from its original science orbit, deplete excess propellant reserves, and be maneuvered into a slightly lower orbit, away from functioning satellites. In close collaboration with the Ocean Surface Topography Science Team, mission partners identified an orbit that would allow for the continuation of the Jason-2/OSTM measurements while still being compatible with orbital-debris mitigation constraints and of scientific benefit.

This new orbit resulted in less frequent observations of the same location on Earth, but overall resolution of the data improved because the ground tracks of the observations were closer together. This improved resolution is extremely useful for marine gravity studies and the mapping of seafloor topography. It also allowed for valuable operational oceanographic and science observations.

"Not only did Jason-2 extend the precise climate record established by TOPEX/Poseidon and continued by Jason-1, it also made invaluable observations for small- to medium-scale ocean studies in its second, interleaved orbit," said CNES President Jean-Yves Le Gall. "Even when moved to the 'graveyard' orbit, Jason-2 continued to make unprecedented new observations of the Earth's gravity field, with precise measurements right until the end."

The technological advancements proven on Jason-1, Jason-2/OSTM and Jason-3 will be put to use well into future decades. Following Jason-3 will be two future Sentinel-6/Jason-CS satellites, planned for launch in 2020 and 2025.

For more information about NASA's Earth science activities, visit:

Images (mentioned), Text, Credits: NASA/Steve Cole/JPL/Esprit Smith/CNES/Pascale Bresson/Raphaël Sart/NOAA/John Leslie/EUMETSAT/Neil Fletcher.


NASA Smallsats Can Aid Hurricane Forecasts with GPS

NASA - CYGNSS Mission patch.

October 10, 2019

Eight briefcase-size satellites flying in a row may be key to improving forecasts of a hurricane's wind speed - detecting whether it will make landfall as a Category 1 or a Category 5. NASA's Cyclone Global Navigation Satellite System (CYGNSS) fleet, launched in 2016, was designed to show whether the same GPS signals your phone uses for navigation can be used to measure winds deep within a hurricane or typhoon. The answer appears to be a resounding yes.

Weather forecasting models have gotten much better at predicting the future track of a hurricane or typhoon, but they haven't improved at predicting its maximum wind speed, which scientists call intensity. That's because these tropical giants are steered by outside forces, such as regional winds, but their intensity depends on forces within each storm. And while many satellites can see the external winds, they can't see through a hurricane's thick clouds and rain.

CYGNSS Principal Investigator Christopher Ruf of the University of Michigan in Ann Arbor explained: "To predict intensity, you have to measure wind speed right in the middle of the storm and, until CYGNSS, there hasn't been a way to do it other than flying Hurricane Hunter planes."

Image above: Illustration of one of the eight CYGNSS satellites in orbit above a hurricane. Image Credit: NASA.

The new CYGNSS data proved to be an excellent match with Hurricane Hunter data collected at the same time during 2017's hurricanes Maria, Irma and Jose. The eight small satellites - orbiting with only a 12-minute gap between each one - collected more data on each storm than could be gathered during a Hurricane Hunter flight.

How to See Through Rain and Clouds

To see what's in the atmosphere, many Earth-observing satellites send out electromagnetic signals with wavelengths that are just fractions of an inch long. To these short-wavelength signals, a drop of drizzle, speck of dust or any other airborne particle is an impenetrable obstacle. Even though the wavelengths are longer than these tiny particles, they are close enough in size that signals bounce off particles like a billiard ball colliding with another ball. By "reading" these scattered signals, researchers can discern the shape and location of clouds and other obstacles that the signals ran into.

In other words, short wavelengths let researchers see a storm but not see through it.

CYGNSS, on the other hand, uses GPS signals. Their wavelength is 7.5 inches (19 centimeters) long - far longer than either the short wavelengths most satellite instruments use or any raindrop ever measured. At that wavelength, Ruf said, "You don't see a raindrop at all. You just go right through it." That enables CYGNSS to see through a hurricane and measure the winds at the ocean surface.

GPS satellites, operated by the U.S. Air Force, are in a much higher orbit than the CYGNSS fleet. As a GPS satellite flies over a tropical cyclone, its signals pass unimpeded through the storm and bounce off the ocean surface. In their lower orbit, CYGNSS's downward-looking GPS receivers are able to intercept signals returning upward. Distortions in these bounced signals show how rough the sea is, enabling researchers to calculate the wind speed that caused the roughness.

Turning Signals Into Measurements

CYGNSS' eight small satellites have worked well since launch, but the mission's scientists ran into a major hurdle on the path to processing the GPS signals into wind speed data. In designing the mission, scientists assumed that GPS signals are broadcast at constant strength. But when the scientists started to collect data, they found that the signal power from most GPS satellites changes during each orbit and that the degree of change differs from satellite to satellite. These variations threw off the CYGNSS satellites' measurements of high winds by as much as 11 mph (18 kph).

"We spent a year or more working on the problem, and we finally got it figured out," Ruf said. "Basically, the Air Force turns the power up when they go over certain parts of the world where bad guys are trying to jam the signals." Stronger signals are harder to jam.

Once the CYGNSS team understood the issue, they found a workaround. Each CYGNSS satellite carries not only a primary GPS receiver to collect signals bouncing up from Earth's surface, but also a secondary, smaller receiver for location and tracking. The team reprogrammed the smaller receivers to measure the strength of the broadcast signal arriving from overhead, which gave them the information they needed to correctly process the signals returning from below.

With that problem solved, the researchers could turn to the task of assessing how CYGNSS data would affect hurricane forecasts.

Experimenting with a research version of the same hurricane model that the National Oceanic and Atmospheric Administration (NOAA) uses for forecasts, the scientists added CYGNSS data to reconstructions of two of 2017's notable storms, hurricanes Harvey and Irma. The addition of CYGNSS data produced more realistic forecasts, not only of the storms' intensity, but of their tracks and structure. Other studies have shown similar improvements in forecasts of different storms.

An Unexpected Watery Bonus

To Ruf's surprise, CYGNSS has proven to have an unforeseen application. The CYGNSS team had planned to routinely turn off their receivers when the satellites fly over land, but the team decided to simplify their operations by having the satellites collect data all the time. Two postdoctoral students at NASA's Jet Propulsion Laboratory in Pasadena, California, decided to look at the data from over land. "It was really luck as much as anything, but it turns out there's all kinds of nice science you can do with the land data to measure soil moisture and flooding," Ruf said.

As the former students, Clara Chew (University Corporation for Atmospheric Research in Boulder, Colorado) and Hugo Carreno-Luengo (Barcelona, Spain), have documented the value of the data, NASA has now officially extended the scope of the mission and invited the science team to redefine the mission purposes. There may be other applications waiting to be discovered as the eight small CYGNSS satellites keep watching hidden winds in tropical storms.

Related links:

CYGNSS data produced more realistic forecasts:


Image (mentioned), Text, Credits: NASA/Earth Science News Team, written by Carol Rasmussen/JPL/Esprit Smith.

Best regards,

AI challenged to stave off collisions in space

ESA - European Space Agency patch.

10 October 2019

ESA is challenging machine learning experts to help forecast and prevent collisions in space. The Agency’s Advanced Concepts Team and Space Debris Office have come together to set up the latest in a series of AI-themed competitions based on actual space data.

Debris strike

Space is not as empty as it used to be. More than 34 000 items of space debris bigger than 10 cm are orbiting our planet. Of those, some 22 300 items are being regularly tracked by the telescopes and powerful radars of the US Space Surveillance Network and their trajectories maintained in a catalogue.

In highly-trafficked orbits, active collision avoidance has become a routine task in space operations. Space surveillance data reveal potential risks for satellites to collide with another space object at multiple kilometres per second – whether from active missions or space debris.

For a typical satellite in low-Earth orbit, hundreds of alerts are issued weekly, in the form of ‘conjunction data messages’. After automatic processing and filtering most of these are found to be low-risk, but that still leaves about two actionable alerts per mission per week, requiring detailed examination by a human analyst.

On average, ESA needs to perform more than one collision avoidance manoeuvre per satellite per year, the vast majority due to space debris.

Predicted conjunction

ESA’s Space Debris Office at the European Space Operations Centre in Darmstadt, Germany, supports collision avoidance activities for the low-Earth-orbiting Aeolus wind-mapping mission, the Cryosat-2 ice mapper and the triple-satellite Swarm constellation, monitoring Earth’s magnetic field.

Their remit also extends to the four-satellite Cluster constellation – probing the magnetic field and its interaction with the solar wind – which is in an eccentric orbit climbing to the geostationary region, as well as more than a dozen missions from partner agencies or commercial operators.

Klaus Merz of the Space Debris Office explains: “The conjunction data messages that highlight these close approaches contain various details such as the identity of the satellite and potential collider, the time of closest approach, minimum distance and uncertainty. From some of these attributes we compute a collision risk.”

Distribution of space debris around Earth

“In the days following the first message, as the uncertainties shrink, follow-up conjunction data messages are released, refining the knowledge acquired on their close encounter. Typically about three new messages become available daily, and over the course of a week the last obtained message can be assumed to include the best knowledge we have about the potential collision of these two objects.

“However we cannot wait for this last data message before taking action: In most cases the Space Debris Office will alert control teams and start thinking about a potential avoidance manoeuvre three days before the closest approach, then make a final decision one day before, based on a threshold of a one in a ten thousand risk of collision.

Spatial density of objects by orbital altitude

“In this challenge we ask competitors to build a model that makes use of the conjunction data messages recorded up to two days prior to the closest approach in order to predict the final risk, contained in the last available message before the approach.”

The Space Debris Office are releasing the last six years of conjunction data messages, with some of the later-stage messages kept hidden, for the competitors asked to predict their end state instead.

“The messages form a time series, so you can see how the risk evolves over time, as the uncertainties on satellite positions and observational errors shrink,” explains Dario Izzo of the Advanced Concepts Team.

“The challenge for machine learning is that the great majority of these conjunction data messages do not actually result in a significant collision risk, so this will be a matter of learning from a few relatively rare events. Out of a very large database, they will be learning only from the tail of the distribution, which makes it more difficult.”

Space debris team at ESOC

This space collision avoidance challenge will be formally launched on Wednesday 16 October, and last for two months. Competing teams will be able to download the Space Debris Office conjunction data message database, provided with the kind permission of the Space Surveillance Network.

The competition is of more than purely academic interest, because the Space Debris Office is planning to develop technologies to further automate the collision avoidance process as part of ESA’s new Space Safety Programme, put forward for approval at November’s Space19+ Ministerial.

This development driven by the predicted growth in low-orbiting satellites and the coming wave of mega-constellations for which detailed case-by-case analysis of every high risk close approach event by human analysts will not be a not a viable option – nor will the actual preparation and execution of avoidance manoeuvres.

Related links:

Space collision avoidance challenge:


Advanced Concepts Team (ACT):

Space debris:

Kelvins competitions website:

Animations, Images, Text, Credits:ESA, CC BY-SA 3.0 IGO.