mercredi 20 juin 2018

New Satellite, Space Research and Cargo Missions Fill Crew Agenda












ISS - Expedition 56 Mission patch.

June 20, 2018

The International Space Station deployed a satellite this morning to demonstrate the potential of removing space junk. Back inside the orbital lab, the Expedition 56 crew explored space physics, studied human research and conducted an emergency drill.


Image above: Astronaut Serena Auñón-Chancellor collects breath samples to analyze and measure red blood cell function for the Marrow investigation. Image Credit: NASA.

A new satellite was deployed into space today from outside the Japanese Kibo laboratory module. Officially named the NanoRacks-Remove Debris satellite, it will explore using a 3D camera to map the location and speed of space debris. It will also deploy a net to capture a nanosatellite that will simulate space junk.

NASA astronaut Ricky Arnold worked inside the Microgravity Science Glovebox to troubleshoot gear today for a semiconductor crystal growth experiment. Alexander Gerst, of the European Space Agency, set up dosimeters and measured the station’s acoustic levels to understand the effects on crews.

Arnold later joined fellow Soyuz MS-08 crewmates Drew Feustel of NASA and Oleg Artemyev of Roscosmos for an emergency drill. The trio practiced evacuating the station in their Soyuz crew ship in the unlikely event of an emergency.

International Space Station (ISS). Image Credits: NASA/STS-132

U.S. and Russian cargo ships are due to launch to the space station this summer. Another cargo craft is due to end its stay at the orbital lab next month. SpaceX is counting down to a June 29 launch of its Dragon cargo ship. Roscosmos will launch its Progress 70 cargo craft on July 9. Finally, the Cygnus space freighter attached to the Unity module is due to end its stay July 15.

Related links:

Marrow: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1673

NanoRacks-Remove Debris satellite: https://www.nasa.gov/mission_pages/station/research/experiments/2456.html

Semiconductor crystal growth: https://www.nasa.gov/mission_pages/station/research/experiments/316.html

SpaceX: https://www.nasa.gov/spacex

Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html

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

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

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

Best regards, Orbiter.ch

Martian Dust Storm Grows Global: Curiosity Captures Photos of Thickening Haze










NASA - Mars Science Laboratory (MSL) logo.

June 20, 2018

A storm of tiny dust particles has engulfed much of Mars over the last two weeks and prompted NASA’s Opportunity rover to suspend science operations. But across the planet, NASA’s Curiosity rover, which has been studying Martian soil at Gale Crater, is expected to remain largely unaffected by the dust. While Opportunity is powered by sunlight, which is blotted out by dust at its current location, Curiosity has a nuclear-powered battery that runs day and night.

The Martian dust storm has grown in size and is now officially a "planet-encircling" (or "global") dust event.


Image above: A self-portrait by NASA's Curiosity rover taken on Sol 2082 (June 15, 2018). A Martian dust storm has reduced sunlight and visibility at the rover's location in Gale Crater. A drill hole can be seen in the rock to the left of the rover at a target site called "Duluth." Image Credits: NASA/JPL-Caltech/MSSS.

Though Curiosity is on the other side of Mars from Opportunity, dust has steadily increased over it, more than doubling over the weekend. The atmospheric haze blocking sunlight, called "tau," is now above 8.0 at Gale Crater — the highest tau the mission has ever recorded. Tau was last measured near 11 over Opportunity, thick enough that accurate measurements are no longer possible for Mars' oldest active rover.

For NASA's human scientists watching from the ground, Curiosity offers an unprecedented window to answer some questions. One of the biggest: Why do some Martian dust storms last for months and grow massive, while others stay small and last only a week?

“We don’t have any good idea,” said Scott D. Guzewich, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, leading Curiosity's dust storm investigation.

Curiosity, he points out, plus a fleet of spacecraft in the orbit of Mars (Odyssey, MRO, Maven and ESA's Mars Express and GTO), will allow scientists for the first time to collect a wealth of dust information both from the surface and from space. The last storm of global magnitude that enveloped Mars was in 2007, five years before Curiosity landed there.


Animation above: In June 2018 NASA's Curiosity Rover used its Mast Camera, or Mastcam, to snap photos of the intensifying haziness the surface of Mars, caused by a massive dust storm. The rover is standing inside Gale Crater looking out to the crater rim. The photos span about a couple of weeks, starting with a shot of the area before the storm appeared. Animation Credit: NASA.

In the animation above, Curiosity is facing the crater rim, about 18.6 miles (30 kilometers) away from where it stands inside the crater. Daily photos captured by its Mast Camera, or Mastcam, show the sky getting hazier. This sun-obstructing wall of haze is about six to eight times thicker than normal for this time of season.

Curiosity's engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, have studied the potential for the growing dust storm to affect the rover's instruments, and say it poses little risk. The largest impact is to the rover's cameras, which require extra exposure time due to the low lighting. The rover already routinely points its Mastcam down at the ground after each use to reduce the amount of dust blowing at its optics. JPL leads the Mars Science Laboratory/Curiosity mission.


Image above: Two images from the Mast Camera (Mastcam) on NASA's Curiosity rover depicting the change in the color of light illuminating the Martian surface since a dust storm engulfed Gale Crater. The left image shows the "Duluth" drill site on Sol 2058 (May 21); the right image is from Sol 2084 (June 17). The cherry red color is due to red dust grains in the atmosphere letting red light through to the surface, but not green or blue, and to different exposure times for the two images. Image Credits: NASA/JPL-Caltech/MSSS.

Martian dust storms are common, especially during southern hemisphere spring and summer, when the planet is closest to the Sun. As the atmosphere warms, winds generated by larger contrasts in surface temperature at different locations mobilize dust particles the size of individual talcum powder grains. Carbon dioxide frozen on the winter polar cap evaporates, thickening the atmosphere and increasing the surface pressure. This enhances the process by helping suspend the dust particles in the air. In some cases, the dust clouds reach up to 40 miles (60 kilometers) or more in elevation.

Though they are common, Martian dust storms typically stay contained to a local area. By contrast, the current storm, if it were happening on Earth, is bigger than North America and Russia combined, said Guzewich.

The dust storm may seem exotic to some Earthlings, but it’s not unique to Mars. Earth has dust storms, too, in desert regions such as North Africa, the Middle East and the southwest United States.

But conditions here prevent them from spreading globally, said Ralph A. Kahn, a Goddard senior research scientist who studies the atmospheres of Earth and Mars. These include the structure of our thicker atmosphere and stronger gravity that helps settle dust. Earth also has vegetation cover on land that binds the soil with its roots and helps block the wind and rain that wash the particles out of the atmosphere.

Related articles:

NASA Encounters the Perfect Storm for Science
https://orbiterchspacenews.blogspot.com/2018/06/nasa-encounters-perfect-storm-for.html

Shades of Martian Darkness
https://orbiterchspacenews.blogspot.com/2018/06/shades-of-martian-darkness.html

Opportunity Hunkers Down During Dust Storm
https://orbiterchspacenews.blogspot.com/2018/06/opportunity-hunkers-down-during-dust.html

Related links:

Mars Science Laboratory (Curiosity): https://www.nasa.gov/mission_pages/msl/index.html

Mast Camera: https://mars.nasa.gov/msl/mission/instruments/cameras/mastcam/

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center, by Lonnie Shekhtman.

Greetings, Orbiter.ch

Once in a Blue Dune












NASA - Mars Reconnaissance Orbiter (MRO) logo.

June 20, 2018


Sand dunes often accumulate in the floors of craters. In this region of Lyot Crater, NASA's Mars Reconnaissance Orbiter (MRO) shows a field of classic barchan dunes on Jan. 24, 2018.

Just to the south of the group of barchan dunes is one large dune with a more complex structure. This particular dune, appearing like turquoise blue in enhanced color, is made of finer material and/or has a different composition than the surrounding.

The map is projected above at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 34.7 centimeters (13.7 inches) per pixel (with 1 x 1 binning); objects on the order of 104 centimeters (40.9 inches) across are resolved.] North is up.

This is a stereo pair with https://www.uahirise.org/ESP_053406_2295

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Mars Reconnaissance Orbiter (MRO): http://www.nasa.gov/mission_pages/MRO/main/index.html

Image, Text, Credits: NASA/Tony Greicius/JPL-Caltech/Univ. of Arizona.

Greetings, Orbiter.ch

XMM-Newton finds missing intergalactic material












ESA - XMM-Newton Mission patch.

20 June 2018

After a nearly twenty-year long game of cosmic hide-and-seek, astronomers using ESA’s XMM-Newton space observatory have finally found evidence of hot, diffuse gas permeating the cosmos, closing a puzzling gap in the overall budget of ‘normal’ matter in the Universe.

While the mysterious dark matter and dark energy make up about 25 and 70 percent of our cosmos respectively, the ordinary matter that makes up everything we see – from stars and galaxies to planets and people – amounts to only about five percent.

 Detecting the warm-hot intergalactic medium

But even this five percent turns out to be quite hard to track down.

The total amount of ordinary matter, which astronomers refer to as baryons, can be estimated from observations of the Cosmic Microwave Background, which is the most ancient light in the history of the Universe, dating back to only about 380 000 years after the Big Bang.

Observations of very distant galaxies allow astronomers to follow the evolution of this matter throughout the Universe’s first couple billions of years. After that, however, more than half of it seemed to have gone missing.

“The missing baryons represent one of the biggest mysteries in modern astrophysics,” explains Fabrizio Nicastro, lead author of the paper presenting a solution to the mystery, published today in Nature.

“We know this matter must be out there, we see it in the early Universe, but then we can no longer get hold of it. Where did it go?”

XMM-Newton

Counting the population of stars in galaxies across the Universe, plus the interstellar gas that permeates galaxies – the raw material to create stars – only gets as far as a mere ten percent of all ordinary matter. Adding up the hot, diffuse gas in the haloes that encompass galaxies and the even hotter gas that fills galaxy clusters, which are the largest cosmic structures held together by gravity, raises the inventory to less than twenty percent.

This is not surprising: stars, galaxies and galaxy clusters form in the densest knots of the cosmic web, the filamentary distribution of both dark and ordinary matter that extends throughout the Universe. While these sites are dense, they are also rare, so not the best spots to look for the majority of cosmic matter.

Astronomers suspected that the ‘missing’ baryons must be lurking in the ubiquitous filaments of this cosmic web, where matter is however less dense and therefore more challenging to observe. Using different techniques over the years, they were able to locate a good chunk of this intergalactic material – mainly its cool and warm components – bringing up the total budget to a respectable 60 percent, but leaving the overall mystery still unsolved. 

The cosmic budget of ‘ordinary’ matter

Fabrizio and many other astronomers around the world have been on the tracks of the remaining baryons for almost two decades, ever since X-ray observatories such as ESA’s XMM-Newton and NASA’s Chandra became available to the scientific community.

Observing in this portion of the electromagnetic spectrum, they can detect hot intergalactic gas, with temperatures around a million degrees or more, that is blocking the X-rays emitted by even more distant sources. 

For this project, Fabrizio and his collaborators used XMM-Newton to look at a quasar – a massive galaxy with a supermassive black hole at its centre that is actively devouring matter and shining brightly from X-rays to radio waves. They observed this quasar, whose light takes more than four billion years to reach us, for a total of 18 days, split between 2015 and 2017, in the longest X-ray observation ever performed of such a source.

“After combing through the data, we succeeded at finding the signature of oxygen in the hot intergalactic gas between us and the distant quasar, at two different locations along the line of sight,” says Fabrizio.

“This is happening because there are huge reservoirs of material – including oxygen – lying there, and just in the amount we were expecting, so we finally can close the gap in the baryon budget of the Universe.”

This extraordinary result is the beginning of a new quest. Observations of different sources across the sky are needed to confirm whether these findings are truly universal, and to further investigate the physical state of this long-sought-for matter.

Cosmic web

Fabrizio and his colleagues are planning to study more quasars with XMM-Newton and Chandra in the coming years. To fully explore the distribution and properties of this so-called warm-hot intergalactic medium, however, more sensitive instruments will be needed, like ESA’s Athena, the Advanced Telescope for High-Energy Astrophysics, scheduled for launch in 2028.

“The discovery of the missing baryons with XMM-Newton is the exciting first step to fully characterise the circumstances and structures in which these baryons are found,” says co-author Jelle Kaastra from the Netherlands Institute for Space Research.

“For the next steps, we will need the much higher sensitivity of Athena, which has the study of the warm-hot intergalactic medium as one of its main goals, to improve our understanding of how structures grow in the history of the Universe.”

“It makes us very proud that XMM-Newton was able to discover the weak signal of this long elusive material, hidden in a million-degree hot fog that extends through intergalactic space for hundreds of thousands of light years,” says Norbert Schartel, XMM-Newton project scientist at ESA.

“Now that we know these baryons are no longer missing, we can’t wait to study them in greater detail.”

Notes for editors:

“Observations of the missing baryons in the warm–hot intergalactic medium” by F. Nicastro et al is published in Nature. DOI: 10.1038/s41586-018-0204-1 

Nature: https://www.nature.com/articles/s41586-018-0204-1

ESA’s XMM-Newton: http://sci.esa.int/xmm-newton/

Images, Text, Credits: ESA/Markus Bauer/Norbert Schartel/SRON – Netherlands Institute for Space Research/Jelle S. Kaastra/Istituto Nazionale di Astrofisica (INAF)/Fabrizio Nicastro/Illustrations and composition: ESA / ATG medialab; data: ESA / XMM-Newton / F. Nicastro et al. 2018; cosmological simulation: R. Cen/courtesy of K. Dolag, Universitäts-Sternwarte München, Ludwig-Maximilians-Universität München, Germany.

Best regards, Orbiter.ch

mardi 19 juin 2018

Crew Packs Up on Science and Cleans Up After Spacewalk












ISS - Expedition 56 Mission patch.

June 19, 2018

The Expedition 56 crew‘s schedule is full of space science today as cleanup continues after last week’s spacewalk. The International Space Station’s three newest crew members also brushed up on their safety skills.


Image above: NASA astronaut Drew Feustel is pictured tethered to the International Space Station just outside of the Quest airlock during a spacewalk he conducted with fellow NASA astronaut Ricky Arnold (out of frame) on June 14, 2018. Image Credit: NASA.

Biology and physics were just part of the microgravity research taking place aboard the orbital laboratory today. NASA astronaut Serena Auñón-Chancellor started her day collecting blood and urine samples for a trio of ongoing human research studies. She then joined European Space Agency astronaut Alexander Gerst for the Myotone study observing how long-term space missions impact the biochemical properties of muscles. Gerst also researched ways to simplify and speed up procedures for astronauts for the Everywear experiment.

Auñón-Chancellor, Gerst and cosmonaut Sergey Prokopyev also gathered midday to review the location of safety gear throughout the space station. The trio also practiced emergency communication in the station’s Russian segment.

NASA astronaut Ricky Arnold spent the day cleaning soot created in a burner during a run of the Advanced Combustion Microgravity Experiment. That study is exploring ways to improve fuel efficiency, reduce pollution and prevent fires in space. Cosmonauts Oleg Artemyev and Prokopyev explored how living in microgravity affects their daily exercise regimen.


Image above: Sunrise over South Indonesia, seen by EarthCam on ISS, speed: 27'598 Km/h, altitude: 408,97 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Live application with EarthCam's from ISS on June 19, 2018 at 21:34 UTC. Image Credits: Orbiter.ch Aerospace/Roland Berga.

Commander Drew Feustel worked in the Quest airlock today continuing cleanup activities after Thursday’s six-hour, 49-minute spacewalk. Feustel scrubbed the U.S. spacesuit water loops then tested water samples for conductivity before wrapping up his day.

Related article:

Spacewalkers Complete HD Camera Installation Work
https://orbiterchspacenews.blogspot.com/2018/06/spacewalkers-complete-hd-camera.html

Related links:

Expedition 56: https://www.nasa.gov/mission_pages/station/expeditions/expedition56/index.html

Everywear: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2041

Advanced Combustion Microgravity Experiment: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1651

Daily exercise regimen: https://www.energia.ru/en/iss/researches/human/26.html

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

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

Images (mentioned), Text, Credits: NASA/Mark Garcia/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Sentinel-3 flies tandem









ESA - Sentinel-3 Mission logo.

19 June 2018

The key to monitoring Earth’s changing environment and to guaranteeing a consistent stream of satellite data to improve our daily lives is to take the same measurements over the course of decades. But how do you know that measurements from successive satellites, even though identical in build, are like for like?

The answer, for the Copernicus Sentinel-3 mission, is to engage in some nifty orbital flying.

Tandem in images

Sentinel-3 is a two-satellite mission to supply the coverage and data delivery needed for Europe’s Copernicus environmental monitoring programme.

Launched in 2016, Sentinel-3A has been measuring our oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics and to provide critical information for marine operations, and more.

Its twin, Sentinel-3B, was launched in April 2018 and is having its instruments calibrated and being commissioned for service. Once Sentinel-3B is operational, the two satellites will orbit Earth 140° apart.

Sentinel-3 spacecraft

Now, however, the satellites have been positioned much closer together, flying a mere 30 seconds apart. Travelling at 7.4 km per second, the separation equates to a distance of 223 km.

The reason for this is to see how their instruments compare.

Even though the two Sentinel-3 satellites are identical, each carrying a radar altimeter, a radiometer and an imaging spectrometer, there’s a chance that their instruments could behave slightly differently.

It is important that any differences are carefully accounted for otherwise the information they deliver could be misinterpreted as changes happening on Earth’s surface.

Given the satellites’ current brief separation, their measurements should be virtually the same.

Sentinel-3 going tandem

This tandem phase is also important for the future Sentinel-3 satellites.

ESA’s ocean scientist, Craig Donlon, explains, “Our Sentinel-3 ocean climate record will eventually be derived from four satellites because we will be launching two further Sentinel-3s in the future.

“We need to understand the small differences between each successive satellite instrument as these influence our ability to determine accurate climate trends.

“The four-month Sentinel-3 tandem phase is a fantastic opportunity to do this and will provide results so that climate scientists can use all Sentinel-3 data with confidence.”

ESA’s Sentinel-3 project manager, Bruno Berruti, said, “Following liftoff and the usual checks, the operations team has been expertly flying Sentinel-3B so that it gradually flies closer to Sentinel-3A.

Sentinel-3 comparison

“We recently reached the magic separation of 30 seconds and I am happy to say that we are now officially in the tandem phase.

“This will last around four months, after which the two satellites will be gently moved apart until they reach their operational separation of 140°. This is different to the other Sentinel missions, but for our mission it is better to measure ocean features such as eddies as accurately as possible.”

ESA’s Sentinel-3 mission manager, Susanne Mecklenburg, added, “So far, we are really happy with the results of the tandem phase. Measurements from the satellites’ instrument packages seem to be very much aligned, but we will be analysing the results very carefully over the next months to make sure we account for any minor differences.”

Related links:

Sentinel-3: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3

Sentinel data access: https://scihub.copernicus.eu/

Images, Text, Credits: ESA/contains modified Copernicus Sentinel data (2018), processed by ESA/S3MPC/ACRI-ST/ESA, CC BY-SA 3.0 IGO.

Best regards, Orbiter.ch

Deep Space Navigation: Tool Tested as Emergency Navigation Device












ISS - International Space Station logo.

June 19, 2018

A tool that has helped guide sailors across oceans for centuries is now being tested aboard the International Space Station as a potential emergency navigation tool for guiding future spacecraft across the cosmos. The Sextant Navigation investigation tests use of a hand-held sextant aboard the space station.


Image above: NASA astronaut Alexander Gerst learns how to use a sextant. “I learned how to navigate after the stars using a sextant,” said Gerst. “It’s actually a test for a backup nav method for #Orion & future deep space missions.” Image Credit: NASA.

Sextants have a telescope-like optical sight to take precise angle measurements between pairs of stars from land or sea, enabling navigation without computer assistance. NASA’s Gemini missions conducted the first sextant sightings from a spacecraft, and designers built a sextant into Apollo vehicles as a navigation backup in the event the crew lost communications from their spacecraft. Jim Lovell demonstrated on Apollo 8 that sextant navigation could return a space vehicle home. Astronauts conducted additional sextant experiments on Skylab.

“The basic concepts are very similar to how it would be used on Earth,” says principal investigator Greg Holt. “But particular challenges on a spacecraft are the logistics; you need to be able to take a stable sighting through a window. We’re asking the crew to evaluate some ideas we have on how to accomplish that and to give us feedback and perhaps new ideas for how to get a stable, clean sight. That’s something we just can’t test on the ground.”


Image above: Jim Lovell demonstrated on Apollo 8 that sextant navigation could return a space vehicle home. Image Credit: NASA.

The investigation tests specific techniques for using a sextant for emergency navigation on space vehicles such as Orion. With the right techniques, crews can use the tool to navigate their way home based on angles between the moon or planets and stars, even if communications and computers become compromised.

“No need to reinvent the wheel when it comes to celestial navigation,” Holt says. “We want a robust, mechanical back-up with as few parts and as little need for power as possible to get you back home safely. Now that we plan to go farther into space than ever before, crews need the capability to navigate autonomously in the event of lost communication with the ground.”

Early explorers put a lot of effort into refining sextants to be compact and relatively easy to use. The tool’s operational simplicity and spaceflight heritage make it a good candidate for further investigation as backup navigation.

Related links:

Sextant Navigation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7646

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

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

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

Images (mentioned), Text, Credits: NASA/Michael Johnson/JSC/International Space Station Program Science Office/Melissa Gaskill.

Greetings, Orbiter.ch