vendredi 26 septembre 2014

Rosetta to deploy lander on 12 November












ESA - Rosetta Mission patch.

26 September 2014

The European Space Agency’s Rosetta mission will deploy its lander, Philae, to the surface of Comet 67P/Churyumov–Gerasimenko on 12 November.

Philae’s landing site, currently known as Site J, is located on the smaller of the comet’s two ‘lobes’, with a backup site on the larger lobe. The sites were selected just six weeks after Rosetta arrived at the comet on 6 August, following its 10-year journey through the Solar System.

Landing site J in Rosetta's NavCam – 21 September

In that time, the Rosetta mission has been conducting an unprecedented scientific analysis of the comet, a remnant of the Solar System’s 4.6 billion-year history. The latest results from Rosetta will be presented on the occasion of the landing, during dedicated press briefings.

The main focus to date has been to survey 67P/Churyumov–Gerasimenko in order to prepare for the first ever attempt to soft-land on a comet.

Site J was chosen unanimously over four other candidate sites as the primary landing site because the majority of terrain within a square kilometre area has slopes of less than 30º relative to the local vertical and because there are relatively few large boulders. The area also receives sufficient daily illumination to recharge Philae and continue surface science operations beyond the initial 64-hour battery-powered phase.

video
Philae’s descent and science on the surface

Over the last two weeks, the flight dynamics and operations teams at ESA have been making a detailed analysis of flight trajectories and timings for Rosetta to deliver the lander at the earliest possible opportunity.

Two robust landing scenarios have been identified, one for the primary site and one for the backup. Both anticipate separation and landing on 12 November.

For the primary landing scenario, targeting Site J, Rosetta will release Philae at 08:35 GMT/09:35 CET at a distance of 22.5 km from the centre of the comet, landing about seven hours later. The one-way signal travel time between Rosetta and Earth on 12 November is 28 minutes 20 seconds, meaning that confirmation of the landing will arrive at Earth ground stations at around 16:00 GMT/17:00 CET.

If a decision is made to use the backup Site C, separation will occur at 13:04 GMT/14:04 CET, 12.5 km from the centre of the comet. Landing will occur about four hours later, with confirmation on Earth at around 17:30 GMT/18:30 CET. The timings are subject to uncertainties of several minutes.

Final confirmation of the primary landing site and its landing scenario will be made on 14 October after a formal Lander Operations Readiness Review, which will include the results of additional high-resolution analysis of the landing sites conducted in the meantime. Should the backup site be chosen at this stage, landing can still occur on 12 November.

Philae’s primary landing site in context

A competition for the public to name the primary landing site will also be announced during the week of 14 October.

The Rosetta orbiter will continue to study the comet and its environment using its 11 science instruments as they orbit the Sun together. The comet is on an elliptical 6.5-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun. Rosetta will accompany the comet for more than a year as they swing around the Sun and back to the outer Solar System again.

The analyses made by the Rosetta orbiter will be complemented by the in situ measurements performed by Philae’s 10 instruments.

An invitation to media with an outline of the programme for the 12 November event will be issued soon. 

More about Rosetta:

Rosetta is an ESA mission with contributions from its Member States and NASA. Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES, and ASI. Rosetta is the first mission in history to rendezvous with a comet. It is escorting the comet as they orbit the Sun, and will deploy a lander.

Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become the key to unlocking the history and evolution of our Solar System, as well as answering questions regarding the origin of Earth’s water and perhaps even life.

Learn more about Rosetta at: http://www.esa.int/rosetta

More about...:

Rosetta overview: http://www.esa.int/Our_Activities/Space_Science/Rosetta_overview

Rosetta factsheet: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_factsheet

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions

In depth:

Rosetta in depth: http://sci.esa.int/rosetta

Related links:

Rosetta at Astrium: http://www.astrium.eads.net/en/programme/rosetta-1go.html

Rosetta at DLR: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10394/

Ground-based comet observation campaign: http://www.rosetta-campaign.net/home

Images, Video, Text, Credits: ESA/Rosetta/NAVCAM/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Best regards, Orbiter.ch

GOCE reveals gravity dip from ice loss









ESA - GOCE Mission logo.

26 September 2014

Although not designed to map changes in Earth’s gravity over time, ESA’s extraordinary satellite has shown that the ice lost from West Antarctica over the last few years has left its signature.

More than doubling its planned life in orbit, GOCE spent four years measuring Earth’s gravity in unprecedented detail.

video
GOCE senses changing gravity

Scientists are now armed with the most accurate gravity model ever produced. This is leading to a much better understanding of many facets of our planet – from the boundary between Earth’s crust and upper mantle to the density of the upper atmosphere.

The strength of gravity at Earth’s surface varies subtly from place to place owing to factors such as the planet’s rotation and the position of mountains and ocean trenches.

Changes in the mass of large ice sheets can also cause small local variations in gravity.

Ice loss dips gravity

Recently, the high-resolution measurements from GOCE over Antarctica between November 2009 and June 2012 have been analysed by scientists from the German Geodetic Research Institute, Delft University of Technology in the Netherlands, the Jet Propulsion Lab in USA and the Technical University of Munich in Germany.

Remarkably, they found that the decrease in the mass of ice during this period was mirrored in GOCE’s measurements, even though the mission was not designed to detect changes over time.

Using gravity data to assess changes in ice mass is not new. The NASA–German Grace satellite, which was designed to measure change, has been providing this information for over 10 years.

However, measurements from Grace are much coarser than those of GOCE, so they cannot be used to look at features such as Antarctica’s smaller ‘catchment basins’.

GOCE geoid

For scientific purposes, the Antarctic ice sheet is often divided into catchment basins so that comparative measurements can be taken to work out how the ice in each basin is changing and discharging ice to the oceans. Some basins are much bigger than others.

By combining GOCE’s high-resolution measurements with information from Grace, scientists can now look at changes in ice mass in small glacial systems – offering even greater insight into the dynamics of Antarctica’s different basins.

They have found that that the loss of ice from West Antarctica between 2009 and 2012 caused a dip in the gravity field over the region.

Ice change from CryoSat

In addition, GOCE data could be used to help validate satellite altimetry measurements for an even clearer understanding of ice-sheet and sea-level change.

ESA’s CryoSat satellite, which carries a radar altimeter, has recently shown that since 2009 the rate at which ice is been lost from the West Antarctic Ice Sheet every year has increased by a factor of three.

And, between 2011 and 2014, Antarctica as a whole has been shrinking in volume by 125 cubic kilometres a year.

Johannes Bouman from the German Geodetic Research Institute said, “We are now working in an interdisciplinary team to extend the analysis of GOCE’s data to all of Antarctica.

“This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass.”

This new research into GOCE’s gravity data revealing ice loss over time is being carried out through ESA’s Earth Observation Support to Science Element.

More information:

STSE ‘GOCE+ Time-Variations’ project:
http://due.esrin.esa.int/stse/projects/stse_project.php?id=135

Geophysical Research Letters:

Bouman et al (2013) Antarctic outlet glacier mass change resolved at basin scale from satellite gravity gradiometry: http://onlinelibrary.wiley.com/doi/10.1002/2014GL060637/abstract

Related links:

DGFI: http://www.dgfi.badw.de/

TU Delft Faculty of Aerospace Engineering: http://www.lr.tudelft.nl/en/

Related missions:

GRACE: http://www.nasa.gov/mission_pages/Grace/

CryoSat: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat

Access GOCE data: http://earth.esa.int/GOCE/

Images, Video, Text, Credits: ESA/DGFI/Planetary Visions/HPF/DLR/Helm et al., The Cryosphere, 2014.

Greetings, Orbiter.ch

Expedition 41 Welcomes New Trio Aboard Station














ROSCOSMOS - Soyuz TMA-14M Mission patch / ISS - Expedition 41 Mission patch.

September 25, 2014

Hatches opened at 1:06am ET at the Space Station. Image Credit: NASA TV

NASA astronaut Butch Wilmore and Russian cosmonauts Alexander Samokutyaev and Elena Serova joined their Expedition 41 crewmates when the hatches between the Soyuz TMA-14M spacecraft and the International Space Station officially opened at 1:06 a.m. EDT. Expedition 41 Commander Max Suraev of the Russian Federal Space Agency and Flight Engineers Reid Wiseman of NASA and Alexander Gerst of the European Space Agency, who arrived at the station in May, welcomed the new crew members aboard their orbital home.

Shortly after docking with the International Space Station, the Soyuz TMA-14M spacecraft's port solar array deployed successfully. The array previously did not deploy when the Soyuz reached orbit. NASA and Roscosmos officials have confirmed that the array poses no long term issue to either standard operations at the station for Expedition 41-42, or for the landing of Barry Wilmore, Alexander Samokutyaev and Elena Serova at the conclusion of their mission in March.


Image above: The new six-member Expedition 41 crew gathers in the Zvezda service module for a welcoming ceremony with family and friends in Baikonur, Kazakhstan. Image Credit: NASA TV.

There are now five spacecraft docked to the station its maximum visiting vehicle capacity. There are two Soyuz vehicles, one Progress 56 resupply ship, Europe’s “Georges Lemaître” ATV-5 and the SpaceX Dragon commercial space freighter which arrived Tuesday morning.

The new crew floated into their new home for a welcoming ceremony and congratulatory calls from family, friends and mission officials in Baikonur. After the ceremony ended the new crew will underwent a mandatory safety orientation to familiarize themselves with escape paths and procedures and locations of safety gear.

Wilmore is starting his second visit to the space station. He piloted space shuttle Atlantis in November 2009 which delivered two EXPRESS Logistics Carriers carrying station gear and returned Expedition 20/21 Flight Engineer Nicole Stott back to Earth.

Samokutyaev is beginning his second stint at the orbital laboratory having served as an Expedition 23/24 Flight Engineer. He is replacing Skvortsov, who left the station two weeks ago, who also served as his crewmate in 2010.

Serova is on her first mission as a cosmonaut. She is Russia’s first female cosmonaut to live and work on the International Space Station.

video
Expedition 41 Docks to International Space Station

They join Commander Max Suraev and Flight Engineers Reid Wiseman and Alexander Gerst. The international crew from Roscosmos, NASA and the European Space Agency has been aboard the orbital complex since May 28 and are due to return home Nov. 9.

Some of the cargo flown aboard this Soyuz will be used in research investigations that are either ongoing or planned aboard the International Space Station. Items such as questionnaires will be delivered to obtain in-flight data about crew member characteristics, such as day-to-day changes in health or incidence of pain or pressure in microgravity.

One such investigation is Space Headaches which uses questionnaires to collect information about the prevalence and characteristics of crew members' headaches in microgravity. This information is used to develop future countermeasures for headaches often caused by intracranial pressure change.

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

Read more about intracranial pressure change: http://www.nasa.gov/content/it-s-all-in-your-head-nasa-investigates-techniques-for-measuring-intracranial-pressure/

Researchers will also use biological sample kits delivered by the Soyuz spacecraft to obtain samples of blood, saliva or urine. The ongoing collection of biological samples from crew members help scientists determine if immune system impairment caused by spaceflight increases the possibility for infection or poses a significant health risk during life aboard the space station.

Expedition 41/42 is scheduled to return home March 11, 2015. Upon their undocking, Expedition 43 will have officially begun with Commander Anton Shkaplerov and Flight Engineers Terry Virts and Samantha Cristoforetti staying behind and taking the helm.


For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA / NASA TV.

Greetings, Orbiter.ch

jeudi 25 septembre 2014

NASA Rover Drill Pulls First Taste From Mars Mountain












NASA - Mars Science Laboratory (MSL) patch.

September 25, 2014


Image above: This image from the Mars Hand Lens Imager (MAHLI) camera on NASA's Curiosity Mars rover shows the first sample-collection hole drilled in Mount Sharp, the layered mountain that is the science destination of the rover's extended mission. Image Credit: NASA/JPL-Caltech/MSSS.

NASA's Curiosity Mars rover has collected its first taste of the layered mountain whose scientific allure drew the mission to choose this part of Mars as a landing site.

video
Curiosity Rover Report: A Taste of Mount Sharp

Video above: NASA's Curiosity Mars rover has collected its first sample from the base of Mount Sharp.

Late Wednesday, Sept. 24, the rover's hammering drill chewed about 2.6 inches (6.7 centimeters) deep into a basal-layer outcrop on Mount Sharp and collected a powdered-rock sample.  Data and images received early Thursday at NASA's Jet Propulsion Laboratory, Pasadena, California, confirmed success of this operation. The powder collected by the drilling is temporarily held within the sample-handling mechanism on the rover's arm.

"This drilling target is at the lowest part of the base layer of the mountain, and from here we plan to examine the higher, younger layers exposed in the nearby hills," said Curiosity Deputy Project Scientist Aswhin Vasavada of JPL. "This first look at rocks we believe to underlie Mount Sharp is exciting because it will begin to form a picture of the environment at the time the mountain formed, and what led to its growth."


Image above: This southeastward-looking vista from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows the "Pahrump Hills" outcrop and surrounding terrain seen from a position about 70 feet (20 meters) northwest of the outcrop. Image Credit: NASA/JPL-Caltech/MSSS.

After landing on Mars in August 2012 but before beginning the drive toward Mount Sharp, Curiosity spent much of the mission's first year productively studying an area much closer to the landing site, but in the opposite direction. The mission accomplished its science goals in that Yellowknife Bay area. Analysis of drilled rocks there disclosed an ancient lakebed environment that, more than three billion years ago, offered ingredients and a chemical energy gradient favorable for microbes, if any existed there.

From Yellowknife Bay to the base of Mount Sharp, Curiosity drove more than 5 miles (8 kilometers) in about 15 months, with pauses at a few science waypoints. The emphasis in mission operations has now changed from drive, drive, drive to systematic layer-by-layer investigation.

"We're putting on the brakes to study this amazing mountain," said Curiosity Deputy Project Manager Jennifer Trosper of JPL. "Curiosity flew hundreds of millions of miles to do this."

Curiosity arrived Sept. 19 at an outcrop called "Pahrump Hills," which is a section of the mountain's basal geological unit, called the Murray formation. Three days later, the rover completed a "mini-drill" procedure at the selected drilling target, "Confidence Hills," to assess the target rock's suitability for drilling. A mini-drill activity last month determined that a rock slab under consideration then was not stable enough for full drilling, but Confidence Hills passed this test.


Image above: This image from the Mars Hand Lens Imager (MAHLI) camera on NASA's Curiosity Mars rover shows an example of a type of geometrically distinctive feature that researchers are using Curiosity to examine at a mudstone outcrop at the base of Mount Sharp. Image Credit: NASA/JPL-Caltech/MSSS.

The rock is softer than any of the previous three targets where Curiosity has collected a drilled sample for analysis.

Between the mini-drill test and the sample-collection drilling, researchers used tools on Curiosity's mast and robotic arm for close-up inspection of geometrically distinctive features on the nearby surface of the rock.

These features on the Murray formation mudstones are the accumulations of resistant materials. They occur both as discrete clusters and as dendrites, where forms are arranged in tree-like branching. By investigating the shapes and chemical ingredients in these features, the team hopes to gain information about the possible composition of fluids at this Martian location long ago.


Image above: This map shows the route driven by NASA's Curiosity Mars rover from the "Bradbury Landing" location where it landed in August 2012 to the "Pahrump Hills" outcrop where it drilled into the lowest part of Mount Sharp. Image Credit: NASA/JPL-Caltech/Univ. of Arizona.

The next step will be to deliver the rock-powder sample into a scoop on the rover's arm. In the open scoop, the powder's texture can be observed for an assessment of whether it is safe for further sieving, portioning and delivery into Curiosity's internal laboratory instruments without clogging hardware. The instruments can perform many types of analysis to identify chemistry and mineralogy of the source rock.

NASA's Mars Science Laboratory Project is using Curiosity to assess ancient habitable environments and major changes in Martian environmental conditions. JPL, a division of Caltech, built the rover and manages the project for NASA's Science Mission Directorate in Washington.

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

You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity

Images (mentioned), Video, Text, Credits: NASA / JPL / Guy Webster.

Greetings, Orbiter.ch

New Station Trio Launches to Expand Expedition 41 to Six












ROSCOSMOS - Soyuz TMA-14M Mission patch.

September 25, 2014


Image above: The Soyuz TMA-14M spacecraft launches on time carrying a new Expedition 41 trio to their new home on orbit. Image Credit: NASA TV.

A new Expedition 41/42 trio is on its way to the International Space Station after lifting off at 4:25 p.m. EDT from the Baikonur Cosmodrome in Kazakhstan. Soyuz Commander Alexander Samokutyaev and Flight Engineers Barry Wilmore and Elena Serova are on a six-hour, four-orbit ride to the International Space Station inside the Soyuz TMA-14M spacecraft.

video
Expedition 41/42 Launches to the International Space Station

There will soon be five spacecraft docked to the station reaching its maximum visiting vehicle capacity. There will be two Soyuz vehicles, one Progress 56 resupply ship, Europe’s “Georges Lemaître” ATV-5 and the SpaceX Dragon commercial space freighter which arrived Tuesday morning.

The Poisk docking compartment will host the new Soyuz when it docks at 10:15 p.m. Hatches between the Soyuz and the station will open around 11:55 p.m. after leak and pressure checks.

The new crew will then float into their new home for a welcoming ceremony and congratulatory calls from family, friends and mission officials in Baikonur. After the ceremony has ended the new crew will undergo a mandatory safety orientation to familiarize themselves with escape paths and procedures and locations of safety gear.

Wilmore is starting his second visit to the space station. He piloted space shuttle Atlantis in November 2009 which delivered two EXPRESS Logistics Carriers carrying station gear and returned Expedition 20/21 Flight Engineer Nicole Stott back to Earth.


Image above: Expedition 41 crew members pose for a photo at the conclusion of the press conference held at the Cosmonaut Hotel in Baikonur, Kazakhstan on Sept. 24, 2014. Image Credit: NASA/Aubrey Gemignani.

Samokutyaev is beginning his second stint at the orbital laboratory having served as an Expedition 23/24 Flight Engineer. He is replacing Skvortsov, who left the station two weeks ago, who also served as his crewmate in 2010.

Serova is on her first mission as a cosmonaut. She is Russia’s first female cosmonaut to live and work on the International Space Station.

They will join their orbiting Expedition 40/41 crewmates Commander Max Suraev and Flight Engineers Reid Wiseman and Alexander Gerst. The international crew from Roscosmos, NASA and the European Space Agency has been aboard the orbital complex since May 28 and are due to return home Nov. 9.


Image above: The Soyuz TMA-14M spacecraft is seen after being raised into a vertical position on the launch pad on Sept. 23, 2014 at the Baikonur Cosmodrome in Kazakhstan.Image Credit: NASA/Aubrey Gemignani.

Some of the cargo flown aboard this Soyuz will be used in research investigations that are either ongoing or planned aboard the International Space Station. Items such as questionnaires will be delivered to obtain in-flight data about crew member characteristics, such as day-to-day changes in health or incidence of pain or pressure in microgravity.

One such investigation is Space Headaches which uses questionnaires to collect information about the prevalence and characteristics of crew members' headaches in microgravity. This information is used to develop future countermeasures for headaches often caused by intracranial pressure change.

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

Read more about intracranial pressure change: http://www.nasa.gov/content/it-s-all-in-your-head-nasa-investigates-techniques-for-measuring-intracranial-pressure/

Researchers will also use biological sample kits delivered by the Soyuz spacecraft to obtain samples of blood, saliva or urine. The ongoing collection of biological samples from crew members help scientists determine if immune system impairment caused by spaceflight increases the possibility for infection or poses a significant health risk during life aboard the space station.

Expedition 41/42 is scheduled to return home March 11, 2015. Upon their undocking, Expedition 43 will have officially begun with Commander Anton Shkaplerov and Flight Engineers Terry Virts and Samantha Cristoforetti staying behind and taking the helm.

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA / NASA TV.

Greetings, Orbiter.ch

A galaxy of deception












ESA - Hubble Space Telescope logo.

25 September 2014

Hubble snaps what looks like a young galaxy in the local Universe

Dwarf galaxy DDO 68

Astronomers usually have to peer very far into the distance to see back in time, and view the Universe as it was when it was young. This new NASA/ESA Hubble Space Telescope image of galaxy DDO 68, otherwise known as UGC 5340, was thought to offer an exception. This ragged collection of stars and gas clouds looks at first glance like a recently-formed galaxy in our own cosmic neighbourhood. But, is it really as young as it looks?

Astronomers have studied galactic evolution for decades, gradually improving our knowledge of how galaxies have changed over cosmic history. The NASA/ESA Hubble Space Telescope has played a big part in this, allowing astronomers to see further into the distance, and hence further back in time, than any telescope before it — capturing light that has taken billions of years to reach us.

The area around dwarf galaxy DDO 68 (ground-based image)

Looking further into the very distant past to observe younger and younger galaxies is very valuable, but it is not without its problems for astronomers. All newly-born galaxies lie very far away from us and appear very small and faint in the images. On the contrary, all the galaxies near to us appear to be old ones.

DDO 68, captured here by the NASA/ESA Hubble Space Telescope, was one of the best candidates so far discovered for a newly-formed galaxy in our cosmic neighbourhood. The galaxy lies around 39 million light-years away from us; although this distance may seem huge, it is in fact roughly 50 times closer than the usual distances to such galaxies, which are on the order of several billions of light years.

By studying galaxies of various ages, astronomers have found that those early in their lives are fundamentally different from those that are older. DDO 68 looks to be relatively youthful based on its structure, appearance, and composition. However, without more detailed modelling astronomers cannot be sure and they think it may be older than it lets on.

video
Zooming in on dwarf galaxy DDO 68

Elderly galaxies tend to be larger thanks to collisions and mergers with other galaxies that have bulked them out, and are populated with a variety of different types of stars — including old, young, large, and small ones. Their chemical makeup is different too. Newly-formed galaxies have a similar composition to the primordial matter created in the Big Bang (hydrogen, helium and a little lithium), while older galaxies are enriched with heavier elements forged in stellar furnaces over multiple generations of stars.

DDO 68 is the best representation yet of a primordial galaxy in the local Universe as it appears at first glance to be very low in heavier elements — whose presence would be a sign of the existence of previous generations of stars.

video
Panning across DDO 68

Hubble observations were carried out in order to study the properties of the galaxy’s light, and to confirm whether or not there are any older stars in DDO 68. If there are, which there seem to be, this would disprove the hypothesis that it is entirely made up of young stars. If not, it would confirm the unique nature of this galaxy. More complex modelling is needed before we can know for sure but Hubble's picture certainly gives us a beautiful view of this unusual object.

The image is made up of exposures in visible and infrared light taken with Hubble's Advanced Camera for Surveys.

Notes:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Link:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Image credit: NASA & ESA/Acknowledgement: A. Aloisi (Space Telescope Science Institute)/Digitized Sky Survey 2 (Acknowledgement: Davide De Martin)/Video:  NASA, ESA, Digitized Sky Survey 2, N. Risinger (Skysurvey.org)/Acknowledgement: A. Aloisi (Space Telescope Science Institute).

Cheers, Orbiter.ch

mercredi 24 septembre 2014

MAVEN Spacecraft Returns First Mars Observations












NASA - MAVEN Mission logo.

September 24, 2014

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has obtained its first observations of the extended upper atmosphere surrounding Mars.

MAVEN Spacecraft Returns First Mars Observations

The Imaging Ultraviolet Spectrograph (IUVS) instrument obtained these false-color images eight hours after the successful completion of Mars orbit insertion by the spacecraft at 10:24 p.m. EDT Sunday, Sept. 21, after a 10-month journey. 

The image shows the planet from an altitude of 36,500 km in three ultraviolet wavelength bands.  Blue shows the ultraviolet light from the sun scattered from atomic hydrogen gas in an extended cloud that goes to thousands of kilometers above the planet’s surface.  Green shows a different wavelength of ultraviolet light that is primarily sunlight reflected off of atomic oxygen, showing the smaller oxygen cloud. Red shows ultraviolet sunlight reflected from the planet’s surface; the bright spot in the lower right is light reflected either from polar ice or clouds.

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft

The oxygen gas is held close to the planet by Mars’ gravity, while lighter hydrogen gas is present to higher altitudes and extends past the edges of the image. These gases derive from the breakdown of water and carbon dioxide in Mars’ atmosphere. Over the course of its one-Earth-year primary science mission, MAVEN observations like these will be used to determine the loss rate of hydrogen and oxygen from the Martian atmosphere.  These observations will allow us to determine the amount of water that has escaped from the planet over time.

MAVEN is the first spacecraft dedicated to exploring the tenuous upper atmosphere of Mars.

Related Links:

NASA's MAVEN website: http://www.nasa.gov/maven

Image without labels: http://www.nasa.gov/sites/default/files/files/IUVS-final-image-not-annotated.png

Images, Text, Credits: NASA / Laboratory for Atmospheric and Space Physics,  University of Colorado.

Cheers, Orbiter.ch

Smallest exoplanet ever found to have water vapour












ESA - Hubble Space Telescope logo.

24 September 2014

Clear skies on exo-Neptune

Artist Illustration of planet HAT-P-11b

Astronomers using data from the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, and the Kepler Space Telescope have discovered clear skies and steamy water vapour on a planet outside our Solar System. The planet, known as HAT-P-11b, is about the size of Neptune, making it the smallest exoplanet ever on which water vapour has been detected. The results will appear in the online version of the journal Nature on 24 September 2014.

The discovery is a milestone on the road to eventually finding molecules in the atmospheres of smaller, rocky planets more akin to Earth. Clouds in the atmospheres of planets can block the view of what lies beneath them. The molecular makeup of these lower regions can reveal important information about the composition and history of a planet. Finding clear skies on a Neptune-size planet is a good sign that some smaller planets might also have similarly good visibility.

Artist Illustration showing clear skies on planet HAT-P-11b

"When astronomers go observing at night with telescopes, they say 'clear skies' to mean good luck," said Jonathan Fraine of the University of Maryland, USA, lead author of the study. "In this case, we found clear skies on a distant planet. That's lucky for us because it means clouds didn't block our view of water molecules."

HAT-P-11b is a so-called exo-Neptune — a Neptune-sized planet that orbits another star. It is located 120 light-years away in the constellation of Cygnus (The Swan). Unlike Neptune, this planet orbits closer to its star, making one lap roughly every five days. It is a warm world thought to have a rocky core, a mantle of fluid and ice, and a thick gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.

Parent star HAT-P-11

Part of the challenge in analysing the atmospheres of planets like this is their size. Larger Jupiter-like planets are easier to observe and researchers have already been able to detect water vapour in the atmospheres of some of these giant planets. Smaller planets are more difficult to probe — and all the smaller ones observed to date have appeared to be cloudy.

The team used Hubble's Wide Field Camera 3 and a technique called transmission spectroscopy, in which a planet is observed as it crosses in front of its parent star. Starlight filters through the rim of the planet's atmosphere and into the telescope. If molecules like water vapour are present, they absorb some of the starlight, leaving distinct signatures in the light that reaches our telescopes.

Ground-based image of the area around HAT-P-11

"We set out to look at the atmosphere of HAT-P-11b without knowing if its weather would be cloudy or not," said Nikku Madhusudhan, from the University of Cambridge, UK, part of the study team. "By using transmission spectroscopy, we could use Hubble to detect water vapour in the planet. This told us that the planet didn't have thick clouds blocking the view and is a very hopeful sign that we can find and analyse more cloudless, smaller, planets in the future. It is groundbreaking!"

Before the team could celebrate they had to be sure that the water vapour was from the planet and not from cool starspots — "freckles" on the face of stars — on the parent star. Luckily, Kepler had been observing the patch of sky in which HAT-P-11b happens to lie for years. Those visible-light data were combined with targeted infrared Spitzer observations. By comparing the datasets the astronomers could confirm that the starspots were too hot to contain any water vapour, and so the vapour detected must belong to the planet.


Image above: A plot of the transmission spectrum for exoplanet HAT-P-11b, with data from NASA's Kepler, Hubble and Spitzer observatories combined. The results show a robust detection of water absorption in the Hubble data. Transmission spectra of selected atmospheric models are plotted for comparison. Image Credit: NASA/ESA/STScI.

The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapour, hydrogen gas, and other yet-to-be-identified molecules. So in fact it is not only the smallest planet to have water vapour found in its atmosphere but is also the smallest planet for which molecules of any kind have been directly detected using spectroscopy [1]. Theorists will be drawing up new models to explain the planet's makeup and origins.

Although HAT-P-11b is dubbed as an exo-Neptune it is actually quite unlike any planet in our Solar System. It is thought that exo-Neptunes may have diverse compositions that reflect their formation histories. New findings such as this can help astronomers to piece together a theory for the origin of these distant worlds.

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Zoom into HAT-P-11

"We are working our way down the line, from hot Jupiters to exo-Neptunes," said Drake Deming, a co-author of the study also from University of Maryland, USA. "We want to expand our knowledge to a diverse range of exoplanets."

The astronomers plan to examine more exo-Neptunes in the future, and hope to apply the same method to smaller super-Earths — massive, rocky cousins to our home world with up to ten times the mass of Earth. Our Solar System does not contain a super-Earth, but other telescopes are finding them around other stars in droves and the NASA/ESA James Webb Space Telescope, scheduled to launch in 2018, will search super-Earths for signs of water vapour and other molecules. However, finding signs of oceans and potentially habitable worlds is likely a way off.

This work is important for future studies of super-Earths and even smaller planets. It could allow astronomers to pick out in advance the planets with atmospheres clear enough for molecules to be detected. Once again, astronomers will be crossing their fingers for clear skies.

Notes:

[1] Molecular hydrogen has been inferred to exist in many planets, including planets smaller than HAT-P-11b, but no molecule has actually been detected, using spectroscopy, in a planet this small, until now.
Notes for editors

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The international team of astronomers in this study consists of J. Fraine (University of Maryland, USA; Pontificia Universidad Católica de Chile, Chile; California Institute of Technology, USA); D. Deming (University of Maryland, USA; NASA Astrobiology Institute, USA); B. Benneke (California Institute of Technology, USA); H. Knutson (California Institute of Technology, USA); A. Jordán (Pontificia Universidad Católica de Chile, Chile); N. Espinoza (Pontificia Universidad Católica de Chile, Chile); N. Madhusudhan (University of Cambridge, UK); A. Wilkins (University of Maryland, USA); K. Todorov (ETH Zürich, Switzerland).

Links:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

STScI release: http://hubblesite.org/newscenter/archive/releases/2014/42

Link to science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1420a.pdf

Link to science paper in Nature: http://www.nature.com/nature/journal/v513/n7519/full/nature13785.html

More information about Hubble, Kepler and Spitzer is online at: http://www.nasa.gov

Images, Text, Credit: ESA/J. Fraine/NASA/JPL-Caltech/Digitized Sky Survey 2/Acknowledgement: Davide De Martin/Video: NASA, ESA, J. Fraine.

Best regards, Orbiter.ch

India's spacecraft reaches Mars orbit










ISRO - Mars Orbiter Mission logo.

September 24, 2014

India's Mars Orbiter Mission successfully entered Mars' orbit Wednesday morning, becoming the first nation to arrive on its first attempt and the first Asian country to reach the Red Planet.

"We have gone beyond the boundaries of human enterprise and human imagination," declared India's Prime Minister Narendra Modi, who watched from the space agency's nerve center in Bangalore. "We have accurately navigated our spacecraft through a route known to a very few."

The staff at the Indian Space Research Organization erupted into applause and cheers after learning that the Mars Orbiter Mission, also known as Mangalyaan, reached the planet's orbit and made history.

Before Wednesday, only the United States, Europe and the Soviets have successfully sent spacecraft to Mars.

Artist's rendering of the MOM orbiting Mars. Image Credit: Wikipedia

"The odds were stacked against us," Modi said. "Of the 51 missions attempted so far, a mere 21 had succeeded. But we have prevailed."

And India reached Mars with significantly less money.

With a price tag of $74 million, the Mars Orbiter Mission cost a mere fraction of the $671 million NASA spent on its MAVEN spacecraft, which arrived to Mars earlier this week. Some space observers noted that India's Mars orbiter cost less than the $100 million budget for the space thriller film "Gravity."

"It shows how optimal is the design, that way we're able to cut cost and we're not compromising quality," said S. Satish, a space expert based in Bangalore.

The groundbreaking Mars mission wasn't without controversy -- with some critics who said India should spend the money on other issues.

The spacecraft launched on November 5, and has traveled over 650 million kilometers to enter Mars orbit. Its mission is to orbit the Red Planet, mapping its surface and studying the atmosphere. The Mars Orbiter kicked off its interplanetary debut with its own Twitter account.

Trajectory of the Mars Orbiter Mission. Graphic Credit: ISRO

The mission has been freighted with patriotic significance for India since its inception and is seen as a symbolic coup over its rival, China, which is also ramping up its space ambitions.

Once nears Mars' orbit, India's spacecraft had to execute a series of complicated and critical maneuvers. About half of all spacecraft sent on missions to the planet have veered off course, malfunctioned or crashed.

India's Mars Orbiter Mission is in the company of NASA's two Mars rovers on the ground, a European orbiter and NASA orbiters including the MAVEN, which has been there since Sunday.

The United States has expressed interest in cooperating with India as their spacecraft gather data about the planet. NASA congratulated India via Twitter.

For more information about Indian Space Research Organisation (ISRO), visit: http://www.isro.org/

For more information about Mars Orbiter Mission, visit: http://www.isro.org/mars/home.aspx

Images (mentioned), Text, Credit: CNN.

Greetings, Orbiter.ch

mardi 23 septembre 2014

Coronal Mass Ejections at Mars












NASA - MAVEN Mission logo.

September 23, 2014

Two main types of explosions occur on the sun: solar flares and coronal mass ejections. Unlike the energy and X-rays produced in a solar flare – which can reach Earth at the speed of light in eight minutes – coronal mass ejections are giant clouds of solar material that take one to three days to reach Earth. Once at Earth, these ejections, also called CMEs, can impact satellites in space or interfere with radio communications. During CME Week from Sept. 22 to 26, 2014, we explore different aspects of these giant eruptions that surge out from the star we live with.

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Mars Evolution

Video above: This video is an artist's concept showing the transition from an ancient, habitable Mars capable of supporting liquid water on its surface to the cold desert world of today. Video Credit: NASA Goddard Conceptual Image Lab/Michael Lentz.

Looking across the Mars landscape presents a bleak image: a barren, dry rocky view as far as the eye can see. But scientists think the vista might once have been quite different. It may have teemed with water and even been hospitable to microbial life. What changed?

One theory is that the continuous blast of solar particles from the sun – the constant stream of solar wind, coupled with more extreme explosions such as coronal mass ejections – might have been the culprit. On Sept. 21, 2014, a new NASA mission, the Mars Atmosphere and Volatile Evolution, or MAVEN, reached Mars after a 10-month journey.  Now safely in orbit around Mars, MAVEN will observe the Martian upper atmosphere, including keeping an eye on just what effect the solar wind and CMEs have on the red planet. Such observations not only help us understand the history of what led to the desert surface we see today, but also pave the way for protecting astronauts on future visits.

Mars Atmosphere and Volatile Evolution, or MAVEN spacecraft

The sun was once substantially more active than it is today.  Our young sun is thought to have frequently – perhaps even daily -- blasted out intense bursts of radiation that are more rare in modern times.  Here on Earth, our atmosphere is largely protected from the solar wind by Earth’s magnetic field, but the evidence indicates that Mars's magnetic field nearly vanished early in the planet’s history.  So, over hundreds of millions of years, the particles from the sun could have worn away the Martian atmosphere, ultimately ripping most of it away and blowing it off into space.  Testing that theory poses problems, though, as it's tough to replicate such extreme conditions. MAVEN's observations of an intense CME hitting Mars, however, could hold clues to what Mars endured, and how it was affected, eons ago.

NASA also cares about CMEs at Mars for another reason: These giant clouds of speeding solar material can impact computers aboard spacecraft and expose astronauts to dangerous radiation.  We must understand such space weather events before sending humans to take their first step on this planet that still holds so many secrets.

Related Link:

More on CME week: http://www.nasa.gov/mission_pages/sunearth/news/cmeweek-2014.html

More on MAVEN and space weather:

MAVEN Solar Wind Ion Analyzer Will Look at Key Player in Mars Atmosphere Loss: http://www.nasa.gov/content/goddard/maven-solar-wind-ion-analyzer-will-look-at-key-player-in-mars-atmosphere-loss/

What MAVEN Would See on Mars on Halloween: http://www.nasa.gov/content/goddard/what-maven-would-see-on-mars-on-halloween/

For more information about MAVEN mission, visit: http://www.nasa.gov/mission_pages/maven/main/

Image, Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center/Karen C. Fox.

Greetings, Orbiter.ch

Fourth Dragon for Commercial Resupply Services Arrives at Station










SpaceX - Falcon 9 / CRS-4 Mission patch.

September 23, 2014

The Dragon commercial cargo craft has completed a two day trip to the International Space Station after launching early Sunday morning. NASA astronaut Reid Wiseman and European Space Agency astronaut Alexander Gerst were at the controls of the robotics workstation in the Cupola when the Canadarm2 grappled Dragon at 6:52 a.m. EST Tuesday.


Image above: Alexander Gerst and Reid Wiseman watch the approach of the SpaceX Dragon from the Cupola. Image Credit: NASA TV.

Dragon will spend the next four weeks attached to the Harmony node as the Expedition 41 trio unloads 4,885 pounds of (2,216 kg) crew supplies, hardware, experiments, computer gear and spacewalk equipment. This is the fourth SpaceX mission for NASA’s Commercial Resupply Services contract, designated SpaceX CRS-4, with eight more missions slated to deliver a minimum of 20 metric tons to the station.

One of the new Earth science experiments Dragon has delivered is the ISS-Rapid Scatterometer to be installed outside the Columbus laboratory. The remote sensing instrument will use radar pulses to observe the speed and direction of winds over the ocean for the improvement of weather forecasting.

Read more about ISS-Rapid Scatterometer: http://www.nasa.gov/mission_pages/station/research/experiments/1067.html

ISS-RapidScat replaces a similar device, QuickScat, which is an inoperable satellite orbiting Earth that performed the same functionality. The Jet Propulsion Laboratory partnered with the International Space Station Program Office to quickly deploy RapidScat which is actually a spare QuickScat device modified for operations on the space station.


Image above: The SpaceX Dragon private space freighter approaches the International Space Station. Image Credit: NASA TV.

Another experiment, one designed by students, will observe fruit flies as a research model for learning how diseases work at the cellular and molecular levels. Ames Research Center has partnered with NanoRacks, a private firm with research facilities on the station, and the Center for the Advancement of Science in Space (CASIS) to support the Ames Student Fruit-Fly Experiment (AFEX) on the orbital laboratory.

Read more about NanoRacks AFEX: http://www.nasa.gov/mission_pages/station/research/experiments/1360.html

At the end of its stay Dragon will be filled with cargo to be returned to Earth where it will be retrieved in the Pacific Ocean off the coast of Baja California after splashdown. Nearly 3,300 pounds (1,486 kg) of cargo will be packed inside Dragon including research for analysis by scientists and computer parts and vehicle hardware to be checked out by engineers.

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U S Cargo Ship Arrives and Grapples at the International Space Station

The next Commercial Resupply Services mission to the space station is Orbital-3 which is targeted to begin Oct. 14 when Orbital Sciences will launch its Cygnus spacecraft from Wallops Flight Facility in Virginia. SpaceX is scheduled to make another flight, SpaceX CRS-5, at the beginning of December for a one month stay, the final mission of the year to the station.

View upcoming missions to the International Space Station: http://www.nasa.gov/missions/highlights/schedule.html

Three new Expedition 41 crew members will arrive at the station after they launch Thursday at 4:25 p.m. EDT. Soyuz Commander Alexander Samokutyaev and Flight Engineers Barry Wilmore and Elena Serova are at the Baikonur Cosmodrome in Kazakhstan making final preparations for their six-hour, four-orbit ride to the station’s Poisk docking compartment inside the Soyuz TMA-14M spacecraft.

Right now the station is home to three space residents, Commander Max Suraev of Roscosmos, Flight Engineer Reid Wiseman of NASA and Flight Engineer Alexander Gerst of the European Space Agency. They are scheduled to return home Nov. 10 Kazakh time after a 5-1/2 month mission that began May 28.

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA/NASA TV.

Best regards, Orbiter.ch

The Fickle El Niño of 2014












NASA/European - Ocean Surface Topography Mission (OSTM)/Jason-2 satellite Mission patch.

September 23, 2014

Prospects have been fading for an El Niño event in 2014, but now there's a glimmer of hope for a very modest comeback. Scientists warn that unless these developing weak-to-modest El Niño conditions strengthen, the drought-stricken American West shouldn't expect any relief.

The latest sea-level-height data from the NASA/European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite mission show a pair of eastward-moving waves of higher sea level, known as Kelvin waves, in the Pacific Ocean -- the third such pair of waves this year. Now crossing the central and eastern equatorial Pacific, these warm waves appear as the large area of higher-than-normal sea surface heights (warmer-than-normal ocean temperatures) hugging the equator between 120 degrees west and the International Dateline. The Kelvin waves are traveling eastward and should arrive off Ecuador in late September and early October.


Image above: The image shows Kelvin waves of high sea level (red/yellow) crossing the Pacific Ocean at the equator. The waves can be related to El Niño events. Green indicates normal sea level, and blue/purple areas are lower than normal. Data are from the NASA/European Jason-2 satellite, collected Sept. 13-22, 2014. Image credit: NASA/JPL-Caltech.

A series of larger atmospheric "west wind bursts" from February through May 2014 triggered an earlier series of Kelvin waves that raised hopes of a significant El Niño event. Just as the warming of the eastern equatorial Pacific by these waves dissipated, damping expectations for an El Niño this year, these latest Kelvin waves have appeared, resuscitating hopes for a late arrival of the event.

The new image is online at: http://www.jpl.nasa.gov/images/earth/elnino/earth20140922-full.jpg

For an overview of 2014's El Niño prospects and Kelvin waves, please see: http://science.nasa.gov/science-news/science-at-nasa/2014/19may_elnino/

Climatologist Bill Patzert of NASA's Jet Propulsion Laboratory, Pasadena, California, says it's too early to know for sure, but he would not be surprised if the latest Kelvin waves are the "last hurrah" for this much-hoped-for El Niño. "Since February 2014, the prospect of an El Niño has waxed and waned. This late in the season, the best we can expect is a weak to moderate event. What comes next is not yet clear. But for the drought-plagued American West, the possibility of a badly needed drenching is fading," said Patzert.

NASA scientists will continue to monitor the Pacific to see what is in store next for the world's climate.

This image was created with data collected by the U.S./European OSTM/Jason-2 satellite during a 10-day period centered on Sept. 18, 2014. It shows a red and yellow area in the central and eastern equatorial Pacific, indicating that the ocean surface is about 4 to 6 inches (10 to 12 centimeters) above normal. Green indicates near-normal conditions. These regions contrast with the western equatorial Pacific, where sea levels (blue and purple areas) are 3 to 6 inches (8 to 15 centimeters) lower than normal.

The height of the ocean water relates, in part, to its temperature, and thus is an indicator of the amount of heat stored in the ocean below. As the ocean warms, the water expands and the sea level rises; as it cools, its level falls. Above-normal height variations along the equatorial Pacific indicate El Niño conditions, while below-normal height variations indicate La Niña conditions. The temperature of the upper ocean can have a significant influence on weather patterns and climate.


Image above: NASA/European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite. Image credit: NASA/JPL-Caltech.

This latest image highlights the processes that occur on time scales of more than a year but usually less than 10 years, such as El Niño and La Niña. The image also highlights faster ocean processes such as Kelvin waves. As Patzert says, "Jason-2 is a fantastic Kelvin wave counter." These processes are known as the interannual ocean signal. To show that signal, scientists refined data for this image by removing trends over the past 21 years, seasonal variations and time-averaged signals of large-scale ocean circulation. For a more detailed explanation of what this type of image means, visit: http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/

The comings and goings of El Niño and La Niña are part of the long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. Jason-2 is a joint effort between NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d'Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). JPL manages the U.S. portion of Jason-2 for NASA's Science Mission Directorate, Washington, D.C. In early 2015, NASA and its international partners CNES, NOAA and EUMETSAT will launch Jason-3, which will extend the timeline of ocean surface topography measurements begun by the Topex/Poseidon and Jason 1 and 2 satellites. Jason-3 will make highly detailed measurements of sea level on Earth to gain insight into ocean circulation and climate change. JPL is a division of the California Institute of Technology.

For a time sequence of the evolution of the 2014 El Nino, visit: http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/archive/

To learn more on NASA's satellite altimetry programs, visit: http://sealevel.jpl.nasa.gov

Images (mentioned), Text, Credits: NASA/JPL/Alan Buis.

Greetings, Orbiter.ch