samedi 20 août 2016

United Launch Alliance Successfully Launches AFSPC-6 Mission for the U.S. Air Force


















ULA - Delta IV / AFSPC-6 Mission poster.


August 20, 2016

Twin GSSAP Satellites Enhance Space Based Situational Awareness


Image above: ULA's Delta IV rocket lifts off with the AFSPC-6 mission for the United States Air Force.

A United Launch Alliance (ULA) Delta IV rocket carrying the AFSPC-6 mission for the United States Air Force lifted off from Space Launch Complex-37 Aug. 19 at 12:52 a.m. EDT. This is ULA’s seventh launch in 2016 and the 110th successful launch since the company was formed in December 2006.

“Thank you to the ULA, Air Force and industry partners for the outstanding teamwork and flawless execution that made today’s mission a success,” said Laura Maginnis, ULA vice president of Custom Services. “This morning’s AFSPC-6 launch is a prime example of why our customers continue to place their trust us to launch our nation’s crucial space capabilities.”

video
Delta IV AFSPC-6 Launch Highlights

This mission was launched aboard a Delta IV Medium+ (4,2) configuration Evolved Expendable Launch Vehicle (EELV) powered by one common booster core. The common booster core was powered by an RS-68A liquid hydrogen/liquid oxygen engine producing 702,000 pounds of thrust. A single RL10B liquid hydrogen/liquid oxygen engine powered the second stage. The booster and upper stage engines are both built by Aerojet Rocketdyne. ULA constructed the Delta IV Medium+ (4,2) launch vehicle in Decatur, Alabama.

The AFSPC-6 mission consists of twin Geosynchronous Space Situational Awareness Program (GSSAP) spacecraft, built by Orbital ATK. The new satellites will join the first two GSSAP spacecraft  launched approximately two years ago aboard a Delta IV launch vehicle. GSSAP is a space-based capability that collects space situational awareness data, allowing for more accurate tracking and characterization of man-made orbiting objects. It has a clear, unobstructed, and distinct vantage point for viewing resident space objects orbiting earth in a near-geosynchronous orbit without the weather or atmosphere disruptions that limit ground-based observations. The data from GSSAP greatly improves our ability to rapidly detect, warn, characterize and attribute disturbances to space systems in the geosynchronous environment.

 GSSAP USAF 1 & 2 satellites

ULA's next launch is the Atlas V OSIRIS-REx spacecraft for NASA. The launch is scheduled for Sept. 8 from Space Launch Complex-41 at Cape Canaveral Air Force Station, Florida.

The EELV program was established by the U.S. Air Force to provide assured access to space for Department of Defense and other government payloads. The commercially developed EELV program supports the full range of government mission requirements, while delivering on schedule and providing significant cost savings over the heritage launch systems.

With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 100 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

For more information on ULA, visit the ULA website at http://www.ulalaunch.com. Join the conversation at http://www.facebook.com/ulalaunch, http://twitter.com/ulalaunch and http://instagram.com/ulalaunch.

Images, Video, Text, Credits: United Launch Alliance (ULA)/Günter Space Page.

Greetings, Orbiter.ch

vendredi 19 août 2016

Hubble Investigates Stellar Shrapnel











NASA - Hubble Space Telescope patch.

Aug. 19, 2016


Several thousand years ago, a star some 160,000 light-years away from us exploded, scattering stellar shrapnel across the sky. The aftermath of this energetic detonation is shown here in this striking image from the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3.

The exploding star was a white dwarf located in the Large Magellanic Cloud, one of our nearest neighboring galaxies. Around 97 percent of stars within the Milky Way that are between a tenth and eight times the mass of the sun are expected to end up as white dwarfs. These stars can face a number of different fates, one of which is to explode as supernovae, some of the brightest events ever observed in the universe. If a white dwarf is part of a binary star system, it can siphon material from a close companion. After gobbling up more than it can handle — and swelling to approximately one and a half times the size of the sun — the star becomes unstable and ignites as a Type Ia supernova.

video
Hubble and the sunrise over Earth

This was the case for the supernova remnant pictured here, which is known as DEM L71. It formed when a white dwarf reached the end of its life and ripped itself apart, ejecting a superheated cloud of debris in the process. Slamming into the surrounding interstellar gas, this stellar shrapnel gradually diffused into the separate fiery filaments of material seen scattered across this skyscape.

For more information about the Hubble Space Telescope, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
https://www.spacetelescope.org/

Image credits: ESA/Hubble & NASA, Y. Chu/Text credits: European Space Agency (ESA)/NASA/Ashley Morrow/Video credit: ESA.

Best regards, Orbiter.ch

Spacewalk Concludes After Commercial Crew Port Installation











ISS - Expedition 48 Mission patch

August 19, 2016

Expedition 48 Commander Jeff Williams and Flight Engineer Kate Rubins concluded their spacewalk at 2:02 EDT. During the five-hour and 58-minute spacewalk, the two NASA astronauts successfully installed the first of two international docking adapters (IDAs).


Image above: Spacewalker Kate Rubins works outside the International Space Station with the SpaceX Dragon space freighter just below her. Image Credit: NASA TV.

The IDAs will be used for the future arrivals of Boeing and SpaceX commercial crew spacecraft in development under NASA’s Commercial Crew Program. Commercial crew flights from Florida’s Space Coast to the International Space Station will restore America’s human launch capability and increase the time U.S. crews can dedicate to scientific research, which is helping prepare astronauts for deep space missions, including the journey to Mars.

video
American Astronauts Install New Docking Port for U S Commercial Crew Vehicles

Space station crew members have conducted 194 spacewalks in support of assembly and maintenance of the orbiting laboratory. Spacewalkers have now spent a total of 1,210 hours and 46 minutes working outside the station.

Keep up with the International Space Station, and its research and crews, at:

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

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

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

Greetings, Orbiter.ch

Gaia's second anniversary marked by successes and challenges












ESA - Gaia Mission patch.

16 August 2016

Operating in the depths of space, far beyond the Moon's orbit, ESA's Gaia spacecraft has now completed two years of a planned five-year survey of the sky. Despite a series of unexpected technical challenges, the mission is on track to complete the most detailed and complex mapping of the heavens ever undertaken.

Selected as one of the 'Cornerstone' missions of ESA's science programme, Gaia is designed to pinpoint the positions, distances, motions and other properties of more than a billion stars. Its three instruments collect astrometric, photometric and spectroscopic data on stars in the Milky Way galaxy, as well as more distant galaxies and quasars, and nearby, but faint Solar System objects.

video
Gaia scanning the sky. Image Credits: ESA/C. Carreau.

Located at the L2 Lagrange point, 1.5 million km from Earth, Gaia surveys the entire sky as it spins on its axis. By repeatedly measuring the positions of the stars with extraordinary accuracy, Gaia is providing a huge treasure trove of data that enables scientists to tease out their distances and motions through our Galaxy.

"More than 50 billion focal plane transits, 110 billion photometric observations and 9.4 billion spectroscopic observations have been successfully processed to date," notes Fred Jansen, ESA's mission manager for Gaia.

The immense volume of data and their complex nature have required a huge effort from the scientists and software developers, distributed across Europe, who make up Gaia's Data Processing and Analysis Consortium (DPAC). The first product of their efforts will be a public data release scheduled for 14 September.

"The spacecraft is working well and the data processing is on the right track," says Timo Prusti, ESA's project scientist for Gaia. "Most of the spacecraft systems that are crucial for the success of our mission have behaved as well as, or even better than, expected.

"These include the focal plane assembly, onboard data handling system, onboard detection of sources, the phased array antenna, and the attitude control and micro-propulsion subsystems."


Images above: The Gaia payload module (left), focal plane assembly (centre), and the phased array antenna (right). Image Credits: ESA/Airbus DS.

Nevertheless, the first two years of Gaia operations have not been without their challenges. A few largely unforeseen problems have occurred, requiring detailed, ongoing investigations by teams from ESA, industry and the DPAC.

One problem detected early in the commissioning phase was associated with water freezing on some parts of the optics, causing a reduction in the sensitivity of the telescopes. The mission team expected some water to be trapped in the spacecraft before launch, followed by freezing once the spacecraft reached orbit and started to outgas. Gaia's mirrors were already equipped with heaters to take care of this. However, the amount of ice was much more than expected and the ice deposits survived the heating procedure that took place early in the mission.

"During the commissioning phase, we noticed that there was a rapid drop in transmission from the mirrors, but this disappeared when the affected optics were heated to remove the ice," says Prusti. "This process of decontamination has now taken place a couple of times, and after each occasion the optics have remained clear for longer periods of time.

"The last heating operation took place in June 2015, and only now is the contamination beginning to return very slowly. However, this is not a major setback, since Gaia can still detect objects down to magnitude 20.5, compared with its optimal detection of stars at magnitude 20.7 [1]. We plan to decontaminate the mirror again in the near future, but we are confident that we have now largely solved this problem, and the impact on the overall mission outcome is minimal."

A second complication is caused by stray light infiltrating into Gaia's focal plane at a level higher than predicted before launch. Light from very bright stars and the Milky Way is reflected onto the focal plane, but the more serious stray light is coming from sunlight being scattered by minute fibres around the edge of the insulating blanket that covers Gaia's 10 m diameter sunshield.


Image above: Fibres on edge of Gaia's sunshield. Image Credits: ESA/Airbus DS.

"This results in higher background 'noise' in the data," explains Prusti. "This is irrelevant for observations of brighter stars, but more significant for fainter stars. We can still easily detect stars of magnitude 20, but the stray light means that we can pinpoint locations of faint stars to an accuracy of 500 microarcseconds [2] instead of the planned 300 microarcseconds. However, it is important to stress that, despite this 'noise', Gaia is still the most accurate star mapper ever built."

Another surprise is a series of minor mechanical vibrations which Timo Prusti dubs 'micro-clanks'.

"Thermal expansion and contraction effects are seen on all spacecraft, which results in so-called 'clanks'," he says. "The mechanical changes on Gaia are much smaller than normal, and the only reason we can detect them is because its attitude control system is so sensitive.

"We have discovered that the micro-clanks cause minute structural changes within the spacecraft which lead to tiny discontinuities in the rotation angle of the spacecraft. They result in small inaccuracies in the timing and positions of the stars as they pass across Gaia's array of CCDs.

"However, we are not too worried about this because we can see when it is happening and we know how to fix it. New software will be implemented next year to remove the effect from the data."

A similar effect is caused by micrometeorites, specks of space dust that strike the spacecraft at high speed. However, this environmental hazard was well understood and predicted before launch.

"Fairly large impacts may occur a few times each month," says Jansen. "If they change the spacecraft's rotation rate by more than 10 milliarcseconds per second, they can adversely affect the science data, but such events are rare and their impact on the overall science data return is very small."

Finally, the Gaia team has been analysing data from a laser device called the 'basic angle monitor'. The instrument is designed to measure, with an extremely high level of accuracy, any variations in the angle of separation between Gaia's two telescopes. This is necessary in order to correct for expected periodic variations in the separation angle caused by thermal changes in the payload as Gaia spins.


Image above: Basic Angle Monitor. Image Credits: TNO, Fred Kamphues.

Knowing this basic angle to an accuracy of 0.5 microarcseconds every 15 minutes is crucial in order to achieve absolute global astrometry – mapping of stellar positions - and it is an essential requirement in the data analysis process. However, during commissioning, it was noted that the basic angle fluctuates periodically, at a level more than 100 times greater than expected.

Careful investigation has concluded that the variation is probably caused by thermal expansion and contraction resulting from some solar heat reaching the payload via the service module.

 "We have confirmed that the basic angle monitor is operating properly and we have been able to model the effect on the ground," says Jansen. "This shows that there is a regular pattern of basic angle variation during each rotation of the spacecraft.

"The spacecraft operations have been tuned to ensure a constant amount of solar heating in order to minimise thermoelastic variations."

 "We have taken the basic angle variation into account while processing the data for the first data release in September and we are continuing efforts to develop software that will largely eliminate the problem for future data releases," says Prusti.

The past two years have been a steep learning curve for all of the Gaia team, especially the DPAC, which has had to cater for the unexpected anomalies by developing additional software beyond that foreseen for the processing required for the first data release.

However, the team is happy with the condition of their spacecraft and confident that they can overcome the lingering observational problems to create the most accurate, detailed sky map ever made.

"Although the mission has experienced a number of technical challenges, all of these have either been mitigated by additional software and analysis, or the mitigating mechanism is known and tested but full implementation is pending," says Jansen. "Overall, through the extensive efforts of ESA, DPAC, and prime contractor Airbus Defence and Space, these effects have had a limited impact on our ability to achieve the mission's original science objectives."

"We are confident that we shall still be able to analyse more than one billion stars, measuring each star's position and motion up to 100 times more accurately than Gaia's predecessor Hipparcos," says Prusti.

Notes:

[1] The magnitude scale is a logarithmic scale used to indicate the apparent brightness of stars. An increase or decrease of 1 magnitude is a change by a factor of 2.512. As an example, a magnitude 20 star is about 400 million times fainter than the brightest star in our sky, Sirius, which has an apparent magnitude of -1.46.

[2] Minutes, or seconds, of arc are used to describe very small angles. An arcminute is 1/60 of a degree and an arcsecond is 1/60 of an arcminute. A microarcsecond, which is one millionth of an arcsecond, is equivalent to the edge of a euro coin on the Moon as seen from Earth.

Further information:

Gaia was launched on 19 December 2013 and after a six-month in-orbit commissioning period, the satellite started routine scientific operations on 25 July 2014.

The first Gaia data release, available online on 14 September, will include the positions and G magnitudes for about one billion stars using observations taken between 25 July 2014 and 16 September 2015.  In addition, parallaxes and proper motions will be available for the brightest two million stars, as part of the Tycho-Gaia Astrometric Solution.

For the first 28 days of the routine scientific operations phase, Gaia operated in a special scanning mode that sampled great circles on the sky that always included the ecliptic poles. Photometric data for RR Lyrae and Cepheid variable stars that were observed frequently during this period will be part of the first data release.

On 21 August 2014, Gaia commenced its main survey operation, employing a scanning law designed to achieve the best possible coverage of the whole sky.

Related Links:

Gaia Data Processing and Analysis Consortium (DPAC): http://www.cosmos.esa.int/web/gaia/dpac

Gaia science community website: http://cosmos.esa.int/gaia

For more information about Gaia mission, visit: http://sci.esa.int/gaia/

Images (mentioned), Video (mentioned), Text, Credits: ESA/ESA Gaia project scientist, Timo Prusti/ESA Gaia mission manager/Fred Jansen.

Best regards, Orbiter.ch

Full-Circle Vista from NASA Mars Rover Curiosity Shows 'Murray Buttes'












NASA - Mars Science Laboratory (MSL) patch.

August 19, 2016


Image above: This 360-degree vista was acquired on Aug. 5, 2016, by the Mastcam on NASA's Curiosity Mars rover as the rover neared features called "Murray Buttes" on lower Mount Sharp. The dark, flat-topped mesa seen to the left of the rover's arm is about 50 feet high and, near the top, about 200 feet wide. Image credits: NASA/JPL-Caltech/MSSS.

Eroded mesas and buttes reminiscent of the U.S. Southwest shape part of the horizon in the latest 360-degree color panorama from NASA's Curiosity Mars rover.

The rover used its Mast Camera (Mastcam) to capture dozens of component images of this scene on Aug. 5, 2016, four years after Curiosity's landing inside Gale Crater.

The visual drama of Murray Buttes along Curiosity's planned route up lower Mount Sharp was anticipated when the site was informally named nearly three years ago to honor Caltech planetary scientist Bruce Murray (1931-2013), a former director of NASA's Jet Propulsion Laboratory, Pasadena, California. JPL manages the Curiosity mission for NASA.


Image above: This July 22, 2016, stereo scene from the Mastcam on NASA's Curiosity Mars Rover shows boulders at a site called "Bimbe" on lower Mount Sharp. They contain pebble-size and larger rock fragments. The image appears three dimensional when viewed through red-blue glasses with the red lens on the left. Image credits: NASA/JPL-Caltech/MSSS.

The buttes and mesas are capped with rock that is relatively resistant to wind erosion. This helps preserve these monumental remnants of a layer that formerly more fully covered the underlying layer that the rover is now driving on.


Animation above: NASA's Curiosity Mars Rover at Murray Buttes (360 View). Animation credits: NASA Jet Propulsion Laboratory.

Early in its mission on Mars, Curiosity accomplished its main goal when it found and examined an ancient habitable environment. In an extended mission, the rover is examining successively younger layers as it climbs the lower part of Mount Sharp. A key goal is to learn how freshwater lake conditions, which would have been favorable for microbes billions of years ago if Mars has ever had life, evolved into harsher, arid conditions much less suited to supporting life. The mission is also monitoring the modern environment of Mars.

These findings have been addressing high-priority goals for planetary science and further aid NASA's preparations for a human mission to the Red Planet.

For more information about Curiosity, visit: http://www.nasa.gov/msl and http://mars.nasa.gov/msl

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/Tony Greicius/JPL/Guy Webster.

Greetings, Orbiter.ch

NASA Monitors the 'New Normal' of Sea Ice








NASA - ICESat-2 Mission logo.

Aug. 19, 2016

This year’s melt season in the Arctic Ocean and surrounding seas started with a bang, with a record low maximum extent in March and relatively rapid ice loss through May. The melt slowed down in June, however, making it highly unlikely that this year’s summertime sea ice minimum extent will set a new record.

“Even when it’s likely that we won’t have a record low, the sea ice is not showing any kind of recovery. It’s still in a continued decline over the long term,” said Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s just not going to be as extreme as other years because the weather conditions in the Arctic were not as extreme as in other years.”

“A decade ago, this year’s sea ice extent would have set a new record low and by a fair amount. Now, we’re kind of used to these low levels of sea ice – it’s the new normal.”


Image above: Visualization of Arctic sea ice extent on Aug. 13, 2016. Image Credits: NASA Goddard's Scientific Visualization Studio.

This year’s sea ice cover of the Barents and Kara seas north of Russia opened up early, in April, exposing the surface ocean waters to the energy from the sun weeks ahead of schedule. By May 31, the extent of the Arctic sea ice cover was comparable to end-of-June average levels. But the Arctic weather changed in June and slowed the sea ice loss. A persistent area of low atmospheric pressure, accompanied by cloudiness, winds that dispersed ice and lower-than-average temperatures, didn’t favor melt.

The rate of ice loss picked up again during the first two weeks of August, and is now greater than average for this time of the year. A strong cyclone is moving through the Arctic, similar to one that occurred in early August 2012. Four years ago, the storm caused an accelerated loss of ice during a period when the decline in sea ice is normally slowing because the sun is setting in the Arctic. However, the current storm doesn’t appear to be as strong as the 2012 cyclone and ice conditions are less vulnerable than four years ago, Meier said.

“This year is a great case study in showing how important the weather conditions are during the summer, especially in June and July, when you have 24 hours of sunlight and the sun is high in the sky in the Arctic,” Meier said. “If you get the right atmospheric conditions during those two months, they can really accelerate the ice loss. If you don’t, they can slow down any melting momentum you had. So our predictive ability in May of the September minimum is limited, because the sea ice cover is so sensitive to the early-to-mid-summer atmospheric conditions, and you can’t foresee summer weather.”


Image above: Arctic sea ice has varied terrain in the summer months, as ridges and melt ponds form and floes break apart. A new NASA satellite called ICESat-2, launching in 2018, will measure the height of sea ice year-round. Image Credits: NASA/Kate Ramsayer.

As scientists are keeping an eye on the Arctic sea ice cover, NASA is also preparing for a new method to measure the thickness of sea ice – a difficult but key characteristic to track from orbit.

"We have a good handle on the sea ice area change," said Thorsten Markus, Goddard’s cryosphere lab chief. "We have very limited knowledge how thick it is."

Research vessels or submarines can measure ice thickness directly, and some airborne instruments have taken readings that can be used to calculate thickness. But satellites haven’t been able to provide a complete look at sea ice thickness in particular during melting conditions, Markus said. The radar instruments that penetrate the snow during winter to measure thickness don’t work once you add in the salty water of the melting sea ice, since the salinity interferes with the radar.

The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, will use lasers to try to get more complete answers of sea ice thickness. The satellite, slated to launch by 2018, will use a laser altimeter to measure the heights of Earth’s surface.


Image above: ICESat-2, will use lasers to try to get more complete answers of sea ice thickness. Image Credit: NASA.

In the Arctic, it will measure the elevation of the ice floes, compared to the water level. However, only about one-tenth of sea ice is above the water surface; the other nine-tenths lie below.

To estimate the entire thickness of the ice floe, researchers will need to go beyond the above-water height measurements, and perform calculations to account for factors like the snow on top of the ice and the densities of the frozen layers. Scientists are eager to see the measurements turned into data on sea ice thickness, Markus said.

"If we want to estimate mass changes of sea ice, or increased melting, we need the sea ice thickness," he said. "It’s critically important to understanding the changes in the Arctic."

For more information about ICESat-2, visit: http://www.nasa.gov/icesat-2 or http://icesat-2.gsfc.nasa.gov/

For up-to-date measurements of Arctic sea ice, visit: http://nsidc.org/arcticseaicenews/

Images (mentioned), Text, Credits: NASA's Goddard Space Flight Center, by Maria-José Viñas and Kate Ramsayer/Karl Hille.

Best regards, Orbiter.ch

jeudi 18 août 2016

Most distant catch for ESA station












ESA - Cassini Mission to Saturn logo.

18 August 2016

An ESA tracking station has acquired signals from the international Cassini spacecraft orbiting Saturn, across more than 1.4 billion km of space.

Following a seven-year journey to Saturn, the NASA/ESA/ASI Cassini orbiter delivered Europe’s Huygens probe to the surface of Saturn’s mysterious moon Titan in January 2005, just a few months after becoming the first spacecraft to enter orbit around the giant gas planet.

Cassini during Grand Finale

Since then, Cassini and Huygens have returned a wealth of information on the Saturnian system to the global scientific community, helping us understand the massive planet, its multiple moons and its hauntingly beautiful system of rings.

Starting later this year, the mission will begin its final phase (see Cassini's Grand Finale) and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data.

The longest call

In an initial test on 10 August, ESA’s tracking station at New Norcia, Western Australia, hosting a 35 m-diameter, 630-tonne deep-space antenna, received signals transmitted by Cassini through 1.44 billion km of space.

New Norcia station

“This was the farthest-ever reception for an ESA station, and the radio signals – travelling at the speed of light – took 80 minutes to cover this vast distance,” says Daniel Firre, responsible for supporting Cassini radio science at ESOC, ESA’s operations centre in Darmstadt, Germany.

“We had to upgrade some software at ESOC, as we discovered that one file used for pointing the antenna did not have enough digits to encode the full distance to Cassini, but the test worked and demonstrated we can catch Cassini’s transmissions.”

Listening across the void

Some types of radio science observations use a ground station to detect signals transmitted from a spacecraft that have reflected off a planet or moon’s surface, or passed through the various layers of its atmosphere – or, in the case of Saturn, its rings.

Effects on the signals provide valuable information on the composition, state and structure of whatever they have passed through.

Tracking stations control room at ESOC

Numerous missions, including ESA’s Venus Express and Mars Express, have used this technique in the past. All three of ESA’s deep-space tracking stations (New Norcia in Australia, Cebreros in Spain and Malargüe in Argentina) were specifically designed to enable a radio science capability.

The Cassini mission has performed radio science observations many times during its time at Saturn. Previously, the mission relied solely on the antennas of NASA's Deep Space Network for these observations.

Now, the addition of ESA tracking capability will help provide the continuous radio contact needed during Cassini radio science activities. The data received by ESA will be delivered to NASA for subsequent scientific analysis.

Radio science during the Grand Finale

Starting in December and running into July 2017, Cassini will conduct a daring series of orbits in which the spacecraft will repeatedly climb high above Saturn’s poles, initially passing just outside its narrow F ring, and then later diving between the uppermost atmosphere and the innermost ring.

When Cassini plunges past Saturn, an ESA station will listen, recording radio signals that will be relayed to NASA.

Grand Finale orbits

These data will provide detailed maps of Saturn’s gravity, revealing the planet’s inner composition and possibly helping solve the mystery of just how fast the interior is rotating. They will also help scientists study the rings.

Until December, a half-dozen more test passes using ESA’s New Norcia and Malargüe stations to receive Cassini signals are planned, after which the two will be used during some two-dozen Grand Finale orbits.

Inter-agency cooperation is a key element

The support is particularly challenging, as listening passes can last up to 30 hours, during which reception will be handed over multiple times between the two ESA stations and NASA’s Canberra deep-space communication complex in Australia; NASA’s Madrid complex will also take part.

“We need uninterrupted signal reception to optimise the Cassini radio science data, so the ESA and NASA stations really have to work in close coordination for recording and handover,” says Manfred Lugert, responsible for ESA’s Estrack ground station network.

Due to geometry, the two ESA stations – located in the southern hemisphere – are ideally able to support Cassini radio science. Northern/southern hemispheric coverage was one factor taken into account when ESA built its station in Argentina in 2012.

“We are really pleased that we can work closely with our NASA colleagues and contribute to Cassini’s incredibly valuable radio science goals,” says Manfred, adding: “It’s an impressive display of what two agencies working together can achieve.”

For more information about Cassini-Huygens mission, visit: http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Related links:

Cassini's Grand Finale: https://saturn.jpl.nasa.gov/mission/grand-finale/overview/

ESA’s Estrack ground station network: http://www.esa.int/Our_Activities/Operations/Estrack

Images, Text, Credits: ESA/ J. Mai/NASA/Jet Propulsion Lab.

Greetings, Orbiter.ch

mercredi 17 août 2016

Weekly Recap From the Expedition Lead Scientist, week of August 8, 2016











ISS - Expedition 48 Mission patch.

Aug. 17, 2016

(Highlights: Week of August 8, 2016) - International Space Station crew members continued an important study into the human heart, and also held the championship round of a space-based robotics competition for middle school students.

NASA astronaut Kate Rubins completed the third microscopy session for the Effects of Microgravity on Stem Cell-Derived Cardiomyocytes (Heart Cells) investigation, recording videos of beating heart cells in the Microgravity Science Glovebox. Spaceflight can cause a variety of health issues with astronauts, which may become problematic the longer crew members stay in microgravity. The Heart Cells study looks at how human heart muscle tissue contracts, grows and changes genetically in microgravity and how those changes vary between subjects. Understanding how heart muscle cells, or cardiomyocytes, change in space can improve efforts to study disease, screen drugs and conduct cell replacement therapy for future space missions.


Image above: NASA astronaut Kate Rubins views beating heart cells through a microscope on the International Space Station. The Heart Cells study examines human heart muscle tissue to learn how it contracts, grows and changes genetically in microgravity. Understanding how heart muscle cells, or cardiomyocytes, change in space can improve efforts to study disease, screen drugs and conduct cell replacement therapy for future space missions. Image Credit: NASA.

Extended stays aboard the station are becoming more common, and future crews will stay in space for even longer periods as they travel on deep-space missions or a journey to Mars. Living without gravity’s influence for long periods can cause negative health effects such as muscle atrophy, including potential atrophy of heart muscle. This investigation cultures heart cells on the station for a month to determine how those muscle cells change on a cellular and molecular level in space, improving understanding of microgravity’s negative effects. Understanding changes to heart muscle cells benefits cardiovascular research on Earth, where heart disease is a leading cause of death in many countries.

Ground scientists captured some amazing images of the Perseid meteor shower using an investigation on the space station to catch video and photos of space rocks falling toward Earth.

The Meteor Composition Determination (Meteor) investigation makes space-based observations of the chemical composition of meteors. The investigation captures high-resolution video and photographs of the atmosphere and uses a software program to search for bright spots, which can later be analyzed on the ground. Measurements made by a spectrograph help determine a meteor's chemical makeup.


Image above: NASA astronaut Jeff Williams, left, and Russian cosmonaut Oleg Skripochka monitor the movements of the SPHERES satellites, a pair of bowling-ball sized satellites that were programmed by middle school students to move about the inside of the International Space Station as part of the Zero Robotics competition. Image Credit: NASA.

Meteors are relatively rare, and are difficult to monitor from the ground because of the interference created by Earth’s atmosphere, which is why the annual Perseid meteor shower was a great opportunity to capture data. Investigating the elemental composition of meteors is important to our understanding of how planets developed. Continuous measurement of meteors and their interaction with Earth's atmosphere could help spot previously undetected or unnoticed meteors as they descended toward the ground. The investigation is installed in the station's Window Observational Research Facility (WORF).

NASA astronaut Jeff Williams and Russian cosmonaut Oleg Skripochka collaborated with a team at the Massachusetts Institute of Technology in Cambridge to complete the final round of competition for the middle school division of the SPHERES Zero Robotics competition. Student teams are challenged to design research for the station by writing programs for tasks the SPHERES satellites can accomplish that would be relevant to future space missions. The bowling-ball-sized satellites can be programmed to move about the space station cabin.

SPHERES stands for Synchronized Position Hold, Engage, Reorient, Experimental Satellites. A major outreach tool as well as scientific investigation, SPHERES Zero Robotics provides a unique and valuable opportunity for students interested in science, technology, engineering and mathematics -- STEM -- careers. In all, 12 U.S. teams sent computer code to the station to be tested with the SPHERES satellites, and a team representing the state of Florida won the competition. A group of Russian teachers also participated as they will start a version of the competition in Russian middle schools next year.

video
Meteors Encountering Earth's Atmosphere: A View From the International Space Station

Video above: This video was recorded August 10 on the International Space Station using a high-resolution video camera that is part of the Meteor Composition Determination Investigation. Within the span of about 10 seconds, two meteors associated with the Perseid meteor shower streak across the sky above Pakistan. Video Credit: NASA.

JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi completed his flight day 30 session of the Circadian Rhythms investigation. Circadian rhythm is the phenomenon of one's "body clock" indicating when it is time to sleep or wake. Astronauts in orbit around Earth are subjected to more than a dozen sunrises every day. Researchers believe a non-24-hour cycle of light and dark affects crewmembers’ circadian rhythm. This ESA (European Space Agency) investigation looks at the role of circadian rhythms and how they change during long-duration spaceflight. The investigation addresses the effects of reduced physical activity, microgravity and an artificially controlled environment.

Changes in body composition and body temperature, which also occur in microgravity, can affect crew members’ circadian rhythms as well. Understanding how these phenomena affect the biological clock will improve performance and health for future crew members and provide a unique comparison for sleep disorders, autonomic nervous system disorders and shift work-related disorders on Earth.

Progress was made on other investigations and facilities this week, including Mouse Epigenetics, Meteor, NREP, ISS Ham and NanoRacks Module-9.

Human research investigations conducted this week include Dose Tracker, Fine Motor Skills, Fluid Shifts, Habitability, Neuromapping, and Space Headaches.

Related links:

Effects of Microgravity on Stem Cell-Derived Cardiomyocytes (Heart Cells) investigation: http://www.nasa.gov/mission_pages/station/research/experiments/1914.html

The Meteor Composition Determination (Meteor) investigation: http://www.nasa.gov/mission_pages/station/research/experiments/1323.html

Window Observational Research Facility (WORF): http://www.nasa.gov/mission_pages/station/research/experiments/358.html

SPHERES Zero Robotics: http://www.nasa.gov/mission_pages/station/research/experiments/690.html

Circadian Rhythms investigation: http://www.nasa.gov/mission_pages/station/research/experiments/892.html

Mouse Epigenetics: http://www.nasa.gov/mission_pages/station/research/experiments/1992.html

ISS Ham: http://www.nasa.gov/mission_pages/station/research/experiments/346.html

Dose Tracker: http://www.nasa.gov/mission_pages/station/research/experiments/1933.html

Fine Motor Skills: http://www.nasa.gov/mission_pages/station/research/experiments/1767.html

Fluid Shifts: http://www.nasa.gov/mission_pages/station/research/experiments/1257.html

Habitability: http://www.nasa.gov/mission_pages/station/research/experiments/1772.html

Neuromapping: http://www.nasa.gov/mission_pages/station/research/experiments/1007.html

Space Headaches: http://www.nasa.gov/mission_pages/station/research/experiments/181.html

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

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

Images (mentioned), Video (mentioned), Text, Credits: NASA/Yuri Guinart-Ramirez, Lead Increment Scientist Expeditions 47 & 48/Kristine Rainey.

Greetings, Orbiter.ch

NASA Prepares to Launch First U.S. Asteroid Sample Return Mission











NASA - Osiris-Rex Mission patch.

Aug. 17, 2016

NASA is preparing to launch its first mission to return a sample of an asteroid to Earth. The mission will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft will travel to the near-Earth asteroid Bennu and bring a sample back to Earth for intensive study. Launch is scheduled for 7:05 p.m. EDT Thursday, Sept. 8 from Cape Canaveral Air Force Station in Florida.

“This mission exemplifies our nation’s quest to boldly go and study our solar system and beyond to better understand the universe and our place in it,” said Geoff Yoder, acting associate administrator for the agency’s Science Mission Directorate in Washington. “NASA science is the greatest engine of scientific discovery on the planet and OSIRIS-REx embodies our directorate’s goal to innovate, explore, discover, and inspire.”

The 4,650-pound (2,110-kilogram) fully-fueled spacecraft will launch aboard an Atlas V 411 rocket during a 34-day launch period that begins Sept. 8, and reach its asteroid target in 2018. After a careful survey of Bennu to characterize the asteroid and locate the most promising sample sites, OSIRIS-REx will collect between 2 and 70 ounces (about 60 to 2,000 grams) of surface material with its robotic arm and return the sample to Earth via a detachable capsule in 2023.


Image above: OSIRIS-REx will travel to near-Earth asteroid Benn on a sample return mission. Image Credit: NASA.

"The launch of OSIRIS-REx is the beginning a seven-year journey to return pristine samples from asteroid Bennu," said OSIRIS-REx Principal Investigator Dante Lauretta of the University of Arizona, Tucson. "The team has built an amazing spacecraft, and we are well-equipped to investigate Bennu and return with our scientific treasure."

OSIRIS-REx has five instruments to explore Bennu:

- OSIRIS-REx Camera Suite (OCAMS) – A system consisting of three cameras provided by the University of Arizona, Tucson, will observe Bennu and provide global imaging, sample site imaging, and will witness the sampling event.

- OSIRIS-REx Laser Altimeter (OLA) – A scanning LIDAR (Light Detection and Ranging) contributed by the Canadian Space Agency will be used to measure the distance between the spacecraft and Bennu's surface, and will map the shape of the asteroid.

- OSIRIS-REx Thermal Emission Spectrometer (OTES) – An instrument provided by Arizona State University in Tempe that will investigate mineral abundances and provide temperature information with observations in the thermal infrared spectrum.

- OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) – An instrument provided by NASA’s Goddard Space Flight Center in Greenbelt, Maryland and designed to measure visible and infrared light from Bennu to identify mineral and organic material.

- Regolith X-ray Imaging Spectrometer (REXIS) – A student experiment provided by the Massachusetts Institute of Technology (MIT) and Harvard University in Cambridge, which will observe the X-ray spectrum to identify chemical elements on Bennu’s surface and their abundances.

Additionally, the spacecraft has two systems that will enable the sample collection and return:

- Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – An articulated robotic arm with a sampler head, provided by Lockheed Martin Space Systems in Denver, to collect a sample of Bennu's surface.

- OSIRIS-REx Sample Return Capsule (SRC) – A capsule with a heat shield and parachutes in which the spacecraft will return the asteroid sample to Earth, provided by Lockheed Martin.

"Our upcoming launch is the culmination of a tremendous amount of effort from an extremely dedicated team of scientists, engineers, technicians, finance and support personnel," said OSIRIS-REx Project Manager Mike Donnelly at Goddard. "I'm incredibly proud of this team and look forward to launching the mission's journey to Bennu and back."

Goddard provides overall mission management, systems engineering, and safety and mission assurance for OSIRIS-REx. Lockheed Martin Space Systems built the spacecraft. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency's Science Mission Directorate in Washington.

For images, video, and more information, visit: http://www.nasa.gov/osiris-rex and http://www.asteroidmission.org

Image (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/Karen Northon/Goddard Space Flight Center/Nancy Jones/Bill Steigerwald/University of Arizona/Erin Morton.

Greetings, Orbiter.ch

Supernova Ejected from the Pages of History












NASA - Chandra X-ray Observatory logo.

Aug. 17, 2016


A new look at the debris from an exploded star in our galaxy has astronomers re-examining when the supernova actually happened. Recent observations of the supernova remnant called G11.2-0.3 with NASA’s Chandra X-ray Observatory have stripped away its connection to an event recorded by the Chinese in 386 CE. Image credit: X-ray: NASA/CXC/NCSU/K. Borkowski et al; Optical: DSS.

Historical supernovas and their remnants can be tied to both current astronomical observations as well as historical records of the event. Since it can be difficult to determine from present observations of their remnant exactly when a supernova occurred, historical supernovas provide important information on stellar timelines. Stellar debris can tell us a great deal about the nature of the exploded star, but the interpretation is much more straightforward given a known age.

New Chandra data on G11.2-0.3 show that dense clouds of gas lie along the line of sight from the supernova remnant to Earth. Infrared observations with the Palomar 5-meter Hale Telescope had previously indicated that parts of the remnant were heavily obscured by dust. This means that the supernova responsible for this object would simply have appeared too faint to be seen with the naked eye in 386 CE. This leaves the nature of the observed 386 CE event a mystery.

A new image of G11.2-0.3 is being released in conjunction with this week’s workshop titled “Chandra Science for the Next Decade” being held in Cambridge, Massachusetts. While the workshop will focus on the innovative and exciting science Chandra can do in the next ten years, G11.2-0.3 is an example of how this “Great Observatory” helps us better understand the complex history of the Universe and the objects within it.

Taking advantage of Chandra’s successful operations since its launch into space in 1999, astronomers were able to compare observations of G11.2-0.3 from 2000 to those taken in 2003 and more recently in 2013. This long baseline allowed scientists to measure how fast the remnant is expanding. Using this data to extrapolate backwards, they determined that the star that created G11.2-0.3 exploded between 1,400 and 2,400 years ago as seen from Earth.

Previous data from other observatories had shown this remnant is the product of a “core-collapse” supernova, one that is created from the collapse and explosion of a massive star. The revised timeframe for the explosion based on the recent Chandra data suggests that G11.2-0.3 is one of the youngest such supernovas in the Milky Way.  The youngest, Cassiopeia A, also has an age determined from the expansion of its remnant, and like G11.2-0.3 was not seen at its estimated explosion date of 1680 CE due to dust obscuration.  So far, the Crab nebula, the remnant of a supernova seen in 1054 CE, remains the only firmly identified historical remnant of a massive star explosion in our galaxy.

This latest image of G11.2-0.3 shows low-energy X-rays in red, the medium range in green, and the high-energy X-rays detected by Chandra in blue. The X-ray data have been overlaid on an optical field from the Digitized Sky Survey, showing stars in the foreground.

Chandra X-ray Observatory. Image Credit: NASA

Although the Chandra image appears to show the remnant has a very circular, symmetrical shape, the details of the data indicate that the gas that the remnant is expanding into is uneven. Because of this, researchers propose that the exploded star had lost almost all of its outer regions, either in an asymmetric wind of gas blowing away from the star, or in an interaction with a companion star. They think the smaller star left behind would then have blown gas outwards at an even faster rate, sweeping up gas that was previously lost in the wind, forming the dense shell. The star would then have exploded, producing the G11.2-0.3 supernova remnant seen today.

The supernova explosion also produced a pulsar − a rapidly rotating neutron star − and a pulsar wind nebula, shown by the blue X-ray emission in the center of the remnant. The combination of the pulsar’s rapid rotation and strong magnetic field generates an intense electromagnetic field that creates jets of matter and anti-matter moving away from the north and south poles of the pulsar, and an intense wind flowing out along its equator.

A paper describing this result appeared in the March 9th, 2016 issue of The Astrophysical Journal and is available online. The authors are Kazimierz Borkowski and Stephen Reynolds, both of North Carolina State University, as well as Mallory Roberts from New York University. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2016/g11/

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Images (mentioned), Text, Credits: NASA/Lee Mohon.

Greetings, Orbiter.ch

How to dock CubeSats














ESA - European Space Agency patch / EPFL - Ecole Polytechnique Fédérale de Lausanne logo.

17 August 2016

The miniature satellites known as CubeSats already play a variety of roles in space. In future they could also serve as the building blocks of other, larger missions by being docked together in orbit.

CubeSats are nanosatellites of standardised dimensions based on multiple 10-cm-sided cubes, which ESA is employing for both educational and technology-demonstration purposes.

Docking CubeSats

“The ability to autonomously rendezvous and dock CubeSats could enable in-orbit assembly of larger structures that simply would not be possible in any other way,” explains Roger Walker, overseeing ESA’s technology CubeSats.

”Think for instance of constructing a very large telescope mirror or radio antenna for astronomy out of separate CubeSat segments, getting around size limitations set by our rocket fairings.”

So as a first step, ESA is part-funding PhD research into autonomous CubeSat docking techniques.

Lining up for CubeSat docking

“We’re looking at the level of guidance, navigation and control performance that would be achievable with the miniaturised sensors and propulsion available to such small satellites, and what kind of docking accuracy might be possible,” said Finn Ankersen, an ESA expert in rendezvous and docking and co-supervisor of the research.

Researcher Camille Pirat of École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland is having his PhD work supported through ESA’s Networking and Partnering Initiative, intended to harness advanced academic research for space applications.

video
CubeSat rendezvous and docking

“My interest in the topic came out of a previous R&D project with ESA, designing a CubeSat mission to test out active space debris removal technologies, such as those that will be needed for ESA’s proposed e.Deorbit mission, to capture and deorbit an entire large derelict satellite from orbit.

“The idea would be to demonstrate the pre-capture approach and synchronising of attitude between the chaser spacecraft and the tumbling target at the CubeSat scale, to prepare for a full-scale mission. It was that work that gave rise to this very interesting question: how can we perform rendezvous and docking between CubeSats?

“The challenge is that CubeSats obviously have tight mass, propellant and power constraints. We will need a positioning accuracy of something like 1 cm, previously achieved by ESA’s ATV supply spacecraft when docking with the International Space Station, but obviously the ATV was orders of magnitude bigger.

ATV docking with ISS

“A CubeSat docking would be more like placing a needle into a 1-cm-diameter hole, employing a limited number of sensors and of course a strictly limited amount of propellant. A high level of onboard autonomy would also be desirable.”

The two nanosatellites would begin by using GPS navigation for the control system to bring them into closer range, with inter-satellite links established at about 20 km from each other.

“Closer in, we’d be relying on camera-based navigation, with LED beacons fitted to the CubeSats to help measure the relative range and attitude between chaser and target. What I’m currently looking at is how changes in lighting conditions might impact this solution – if sunglare would be a problem, for example.”

ESA CubeSats in flight

Cold-gas thrusters are currently being baselined, although electric propulsion would offer a way of squeezing extra efficiency out of scarce onboard fuel for longer-range rendezvous operations – with knock-on effects for the size and capacity of solar arrays.

“I’m doing the work in Switzerland, but with regular visits to ESA’s ESTEC technical centre in the Netherlands,” adds Camille Pirat. “This gives me the chance to confer with Roger and also veterans of ESA’s ATV spacecraft such as Finn – it was such a great programme, it’s very useful to be able to learn from their experience.”

Related links:

Technology CubeSats: http://www.esa.int/Our_Activities/Space_Engineering_Technology/Technology_CubeSats

Setting a satellite to catch a satellite: http://orbiterchspacenews.blogspot.ch/2016/07/setting-satellite-to-catch-satellite.html

EPFL (Ecole Polytechnique Fédérale de Lausanne): http://www.epfl.ch/

ATV (Automated Transfer Vehicle): http://www.esa.int/ESA_in_your_country/Germany/ESA-Special_Mit_dem_ATV_zur_Raumstation

Swiss Space Center (EPFL): http://space.epfl.ch/

Images, Video, Text, Credits: ESA/EPFL/Jamani Caillet/NASA.

Best regards, Orbiter.ch

mardi 16 août 2016

NASA Space Robotics Challenge Prepares Robots for the Journey to Mars












NASA / ESA - Space Robotics logo.

Aug. 16, 2016

NASA, in partnership with Space Center Houston, the Official Visitor Center of NASA Johnson Space Center, and NineSigma, a global innovation consultant organization, has opened registration for a new competition -- the Space Robotics Challenge. This event seeks to develop the capabilities of humanoid robots to help astronauts on the journey to Mars.

The Space Robotics Challenge is a $1 million prize competition designed to push the boundaries of robotic dexterity. Teams must program a virtual robot, modeled after NASA’s Robonaut 5 (R5) robot, to complete a series of tasks in a simulation that includes periods of latency to represent communications delay from Earth to Mars.

Though some dexterity has been developed for Earth-based robotics systems using hydraulics, such robots cannot be used in space because of the below-freezing temperatures and the harsh environment of planetary surfaces. The R5 uses elastics technology instead of hydraulics – an innovative way of addressing the problems of operating in space. This technology could also benefit humankind on Earth, as they could operate under dangerous or extreme environments on our home planet.


Image above: The Space Robotics Challenge offers a $1 million prize purse for teams that successfully program a virtual Robonaut 5 robot through a series of complex tasks in a simulated Mars habitat. Image Credit: NASA.

“Precise and dexterous robotics, able to work with a communications delay, could be used in spaceflight and ground missions to Mars and elsewhere for hazardous and complicated tasks, which will be crucial to support our astronauts,” said Monsi Roman, program manager of NASA’s Centennial Challenges. “NASA and our partners are confident the public will rise to this challenge, and are excited to see what innovative technologies will be produced.”

The competition will be held in a virtual environment. Each team’s R5 will be challenged with resolving the aftermath of a dust storm that has damaged a Martian habitat. This involves three objectives: aligning a communications dish, repairing a solar array, and fixing a habitat leak.

Registration for the Space Robotics Challenge begins today, with a qualifying round running from mid-September to mid-November. Finalists of that round will be announced in December and will engage in open practice from January to early June 2017. The final virtual competition will be held in June 2017, and winners will be announced at the end of June at Space Center Houston.

Software developed through this challenge will be transferable across other robotics systems, allowing the technology produced to be used both with older robotics models, such as the Robonaut 2, and any future models developed.

With the technology generated by this challenge, robots could participate in precursor missions to selected landing sites, arriving long before astronauts to set up habitats, life support systems, communications and solar apparatuses, and even begin preliminary scientific research.

NASA’s Centennial Challenges program is part of the agency’s Space Technology Mission Directorate, and is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama. STMD uses challenges to gather the best and brightest minds in academia, industry, government and the Nation to drive innovation and enable solutions in important technology focus areas. Innovators from diverse backgrounds, within and outside of the aerospace industry, are invited to be contributors to our Journey to Mars.

Space Center Houston is a part of the Manned Space Flight Education Foundation, a nonprofit science and space learning center.

NineSigma, based in Cleveland, Ohio, connects organizations with external innovation resources to accelerate innovation in private, public and social sectors.

Related links:

Space Technology Mission Directorate: http://www.nasa.gov/directorates/spacetech/home/index.html

Space Center Houston: http://www.spacecenter.org/

NineSigma: http://www.ninesigma.com/

For more information on the Space Robotics Challenge, visit: http://nasa.gov/spacebot

Image (mentioned), Text, Credits: NASA/Gina Anderson/Loura Hall/Marshall Space Flight Center/Molly Porter.

Greetings, Orbiter.ch

“Kitchen Smoke” Molecules in Nebula Offer Clues to the Building Blocks of Life












NASA & DLR - SOFIA Mission patch.

Aug. 16, 2016


Image above: SOFIA is a Boeing 747SP jetliner modified to carry a 100-inch diameter telescope. Image Credit: NASA.

Using data collected by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) and other observatories, an international team of researchers has studied how a particular type of organic molecules, the raw materials for life – could develop in space. This information could help scientists better understand how life could have developed on Earth.

Bavo Croiset of Leiden University in the Netherlands and his collaborators focused on a type of molecule called polycyclic aromatic hydrocarbons (PAHs), which are flat molecules consisting of carbon atoms arranged in a honeycomb pattern, surrounded by hydrogen. PAHs make up about 10 percent of the carbon in the universe, and are found on the Earth where they are released upon the burning of organic material such as meat, sugarcane, wood etc.  Croiset’s team determined that when PAHs in the nebula NGC 7023, also known as the Iris Nebula, are hit by ultraviolet radiation from the nebula’s central star, they evolve into larger, more complex molecules. Scientists hypothesize that the growth of complex organic molecules like PAHs is one of the steps leading to the emergence of life.

Some existing models predicted that the radiation from a newborn, nearby massive star would tend to break down large organic molecules into smaller ones, rather than build them up. To test these models, researchers wanted to estimate the size of the molecules at various locations relative to the central star.

Croiset’s team used SOFIA to observe Nebula NGC 7023 with two instruments, the FLITECAM near-infrared camera and the FORCAST mid-infrared camera. SOFIA’s instruments are sensitive to two wavelengths that are produced by these particular molecules, which can be used to estimate their size. The team analyzed the SOFIA images in combination with data previously obtained by the Spitzer infrared space observatory, the Hubble Space Telescope and the Canada-France-Hawaii Telescope on the Big Island of Hawaii.


Image above: Combination of three color images of NGC 7023 from SOFIA (red & green) and Spitzer (blue) show different populations of PAH molecules. Image Credits: NASA/DLR/SOFIA/B. Croiset, Leiden Observatory, and O. Berné, CNRS; NASA/JPL-Caltech/Spitzer.

The analysis indicates that the size of the PAH molecules in this nebula vary by location in a clear pattern. The average size of the molecules in the nebula’s central cavity, surrounding the illuminating star, is larger than on the surface of the cloud at the outer edge of the cavity.

In a paper published in Astronomy and Astrophysics, The team concluded that this molecular size variation is due both to some of the smallest molecules being destroyed by the harsh ultraviolet radiation field of the star, and to medium-sized molecules being irradiated so they combine into larger molecules. Researchers were surprised to find that the radiation resulted in net growth, rather than destruction.

“The success of these observations depended on both SOFIA’s ability to observe wavelengths inaccessible from the ground, and the large size of its telescope, which provided a more detailed map than would have been possible with smaller telescopes,” said Olivier Berné at CNRS, the National Center for Scientific Research in Toulouse, France, one of the published paper’s co-authors.

Related link:

Astronomy and Astrophysics: http://www.aanda.org/articles/aa/abs/2016/06/aa27714-15/aa27714-15.html

For more information on SOFIA, go to: http://www.nasa.gov/sofia

For more information SOFIA Science, go to: https://www.sofia.usra.edu/

Images (mentioned), Text, Credits: NASA/Kassandra Bell/SOFIA Science Center, NASA Ames Research Center/Dr. Dana Backman.

Greetings, Orbiter.ch