Galileo satellite set for new orbit

ESA - Galileo Navigation Satellites logo.

10 November 2014

ESA’s fifth Galileo navigation satellite, one of two left in the wrong orbit this summer, will make a series of manoeuvres this month as a prelude to its health being confirmed.

The aim is to raise the lowest point of its orbit – its perigee – to reduce the radiation exposure from the Van Allen radiation belts surrounding Earth, as well as to put it into a more useful orbit for navigation purposes.

Fifth Galileo is now Earth-pointing

Should the two-week operation prove successful then the sixth Galileo satellite will follow the same route.

The Galileo pair, launched together on a Soyuz rocket on 22 August, ended up in an elongated orbit travelling out to 25 900 km above Earth and back down to 13 713 km.

The target orbit was a purely circular one at an altitude of 23 222 km. In addition, the orbits are angled relative to the equator less than originally planned.

The two satellites have only enough fuel to lift their altitude by about 4000 km – insufficient to correct their orbits entirely.

But the move will take the fifth satellite into a more circular orbit than before, with a higher perigee of 17 339 km.

Galileo orbits viewed from above

“The new orbit will fly over the same location every 20 days,” explains Daniel Navarro-Reyes, ESA Galileo mission analyst.

“The standard Galileo repeat pattern is every 10 days, so achieving this will synchronise the ground track with the rest of the Galileo satellites.

“In addition, from a user receiver point of view, the revised orbit will reduce the variation in signal levels, reduce the Doppler shift of the signal, and increase the satellite’s visibility.

“For the satellite, reducing its radiation exposure in the Van Allen radiation belts will protect it from further exposure to charged particles.

“The orbit will also allow Galileo’s Earth Sensor to hold a stable direction for the satellite’s main antenna to point at Earth.

“Right now, when the satellite dips to its lowest point, Earth appears so large that the sensor is unusable. The satellite relies on gyroscopes alone, degrading its attitude precision.”

Galileo orbits viewed side-on

The recovery is being overseen from the Galileo Control Centre in Oberpfaffenhofen, Germany, with the assistance of ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany.

France’s CNES space agency is providing additional ground stations so that contact can be maintained with the satellite as needed.

The two satellites were previously Sun-pointing. “On 3 November that changed for the fifth satellite, as it transitioned to normal Earth-pointing mode,” adds Daniel.

During November, some 15 manoeuvres will take the satellite into its new orbit. Once there, it can formally begin in-orbit testing. The host satellite’s health is checked first, followed by more detailed navigation payload testing.

Related links:

Galileo factsheet (PDF): http://download.esa.int/docs/Galileo_IOV_Launch/Galileo_factsheet_2012.pdf

Galileo on the ground: http://www.esa.int/Our_Activities/Navigation/The_future_-_Galileo/Galileo_on_the_ground

Team of teams: http://www.esa.int/Our_Activities/Operations/Highlights/Team_of_teams

Flight Dynamics: http://www.esa.int/Our_Activities/Operations/Ground_Systems_Engineering/Flight_Dynamics

Images, Text, Credits: ESA/P. Carril.

Greetings, Orbiter.ch

Rosetta - Target locked

ESA - Rosetta Mission patch.

November 10, 2014

Agilkia landing site, 6 November 2014

The Agilkia landing site is seen on this image of Comet 67P/Churyumov–Gerasimenko, taken with Rosetta’s navigation camera on 6 November, just days before its lander Philae makes its historic descent to the surface.

The image presented here is a mosaic of four individual NavCam frames, captured from a distance of 30.5 km from the comet centre on 6 November while Rosetta was en route to the separation trajectory from which it will deploy Philae on 12 November. At this distance, the image scale is 2.6 m/pixel, and the mosaic measures 3.7 x 3.3 km.

The landing site, covering about one square kilometre, is located close to the top of this image, above the easily recognisable, boulder-filled depression that characterises the smaller of the comet’s two lobes. Although it may not seem like it from this image, Agilkia – previously known as Site J – presented the least hazardous terrain of all the landing sites considered during the selection process.

Much of the surface of the comet is covered in boulders – some larger than houses – as well as steep slopes, deep pits and towering cliffs. In the lower part of this image, the narrowness of the neck region connecting the two lobes is emphasised, with the rugged terrain of the larger lobe in the background.

Artist's view of Philae touchdown on Agilkia landing site

On 12 November, Rosetta will release Philae from an altitude of 22.5 km from the comet centre at 08:35 GMT/09:35 CET, with signals confirming deployment arriving at Earth 28 minutes later.

Philae will take about seven hours to descend to the surface, with the signal confirming a successful touchdown expected to arrive on Earth in a one-hour window centred on 16:02 GMT/17:02 CET.

Follow the landing events live via esa.int/rosetta: http://rosetta.esa.int/

The four individual images making up this mosaic are available via the blog: http://blogs.esa.int/rosetta/2014/11/10/cometwatch-6-november-target-locked/

Images, Text, Credits: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0.

Cheers, Orbiter.ch

Expedition 41 Lands Safely in Kazakhstan

ROSCOSMOS - Soyuz TMA-13M Mission patch.

November 10, 2014

Image above: The Soyuz TMA-13M carrying the Expedition 41 trio fires its soft-landing engines right on time at 03:58 GMT (04:58 CET). Image Credit: NASA TV.

Expedition 41 Flight Engineers Reid Wiseman of NASA, Alexander Gerst of the European Space Agency and Commander Maxim Suraev of the Russian Federal Space Agency (Roscosmos) landed their Soyuz TMA-13M spacecraft in Kazakhstan at 03:58 GMT (04:58 CET). The trio arrived at the International Space Station on May 29, and spent more than five months conducting research and maintenance activites.

 

Video above: International Space Station Expedition 41 Astronaut Crew Lands Safely in Kazakhstan. Video Credit: NASA TV.

Russian recovery teams will help the crew exit the Soyuz vehicle and adjust to gravity after their stay in space. Wiseman, Gerst and Suraev spent 165 days aboard the space station and clocked more than 70 million miles during their time in space.

This was the first mission for both Wiseman and Gerst. Suraev now has spent 334 days in space during two missions, including Expeditions 21 and 22.

Image above: Screens at the Mission Control Center in Russia signify a safe landing for the Expedition 41 trio inside the Soyuz TMA-13M spacecraft. Image Credit: NASA TV.

The station now is occupied by Expedition 42 Commander Barry “Butch” Wilmore of NASA and Flight Engineers Alexander Samokutyaev and Elena Serova of Roscosmos. They will remain aboard the station to continue research and maintenance until the remainder of the Expedition 42 crew arrives later this month. NASA astronaut Terry Virts, Russian cosmonaut Anton Shkaplerov and ESA astronaut Samantha Cristoforetti are scheduled to launch from Baikonur, Kazakhstan, Nov. 23, (U.S. time).

Image above: ESA astronaut Alexander Gerst, Russian commander Maxim Suraev and NASA astronaut Reid Wiseman returned to Earth today, landing in the Kazakh steppe. Image Credit: ESA/S. Corvaja.

Alexander performed over 50 experiments during his flight on the weightless research centre as it circled our planet 400 km up. In just two weeks, ESA astronaut Samantha Cristoforetti will continue many of the experiments and begin new ones when she is launched on her ‘Futura’ mission.

Highlights of Alexander’s ‘Blue Dot’ mission included installing ESA’s furnace that can suspend and cool molten metal in mid-air, a spacewalk to maintain and improve the Space Station, and the docking of Europe’s last Automated Transfer Vehicle – the largest spacecraft to supply the research centre.

A large selection of photographs from Blue Dot, most taken by Alexander himself, is available on the Flickr page: http://www.flickr.com/photos/astro_alex

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

Images (mentioned), Video (mentioned), Text, Credit: NASA/ ESA.

Greetings, Orbiter.ch

MUSE Reveals True Story Behind Galactic Crash

ESO - European Southern Observatory logo.

10 November 2014

MUSE view of the ram-pressure stripped galaxy ESO 137-001

The new MUSE instrument on ESO’s Very Large Telescope (VLT) has provided researchers with the best view yet of a spectacular cosmic crash. The new observations reveal for the first time the motion of gas as it is ripped out of the galaxy ESO 137-001 as it ploughs at high speed into a vast galaxy cluster. The results are the key to the solution of a long-standing mystery — why star formation switches off in galaxy clusters.

A team of researchers led by Michele Fumagalli from the Extragalactic Astronomy Group and the Institute for Computational Cosmology at Durham University, were among the first to use ESO’s Multi Unit Spectroscopic Explorer (MUSE) instrument on the VLT. Observing ESO 137-001 — a spiral galaxy 200 million light-years away in the southern constellation of Triangulum Australe (The Southern Triangle) — they were able to get the best view so far of exactly what is happening to the galaxy as it hurtles into the Norma Cluster.

MUSE view of the ram-pressure stripped galaxy ESO 137-001

MUSE gives astronomers not just a picture, but provides a spectrum — or a band of colours — for each pixel in the frame. With this instrument researchers collect about 90 000 spectra every time they look at an object, and thereby record a staggeringly detailed map of the motions and other properties of the observed objects [1].

The galaxy ESO 137-001 in the constellation of Triangulum Australe

ESO 137-001 is being robbed of its raw materials by a process called ram-pressure stripping, which happens when an object moves at high speed through a liquid or gas. This is similar to how air blows a dog’s hair back when it sticks its head out of the window of a moving car. In this case the gas is part of the vast cloud of very thin hot gas that is enveloping the galaxy cluster into which ESO 137-001 is falling at several million kilometres per hour [2].

Wide-field view of the sky around the galaxy ESO 137-001

The galaxy is being stripped of most of its gas — the fuel needed to make the next generations of young blue stars. ESO 137-001 is in the midst of this galactic makeover, and is being transformed from a blue gas-rich galaxy to a gas-poor red one. Scientists propose that the observed process will help to solve a long-standing scientific riddle.

“It is one of the major tasks of modern astronomy to find out how and why galaxies in clusters evolve from blue to red over a very short period of time,” says Fumagalli. “Catching a galaxy right when it switches from one to the other allows us to investigate how this happens.”

Hubble and Chandra composite of ESO 137-001

Observing this cosmic spectacle, however, is no mean feat. The Norma Cluster lies close to the plane of our own galaxy, the Milky Way, so it is hidden behind copious amounts of galactic dust and gas.

With the help of MUSE, which is mounted on one of the VLT’s 8-metre Unit Telescopes at the Paranal Observatory in Chile, scientists could not only detect the gas in and around the galaxy, but were able to see how it moves. The new instrument is so efficient that a single hour of observing time was sufficient to obtain a high resolution image of the galaxy as well as the distribution and motion of its gas.

Zooming in on ESO 137-001

The observations show that the outskirts of ESO 137-001 are already completely devoid of gas. This is a result of the cluster gas — heated to millions of degrees — pushing the cooler gas out of ESO 137-001 as this drives towards the centre of the cluster. This happens first in the spiral arms where the stars and matter are more thinly spread than at the centre, and gravity has only a relatively weak hold over the gas. In the centre of the galaxy, however, the gravitational pull is strong enough to hold out longer in this cosmic tug-of-war and gas is still observed.

Eventually, all of the galactic gas will be swept away into bright streaks behind ESO 137-001 — telltale remnants of this dramatic robbery. The gas that is torn away from the galaxy is mixed with the hot cluster gas to form magnificent tails extending to a distance of over 200 000 light-years. The team had a closer look at these streams of gas to better understand the turbulence created by the interaction.

MUSE shows ESO 137-001 in three dimensions

Surprisingly the new MUSE observations of this gas plume show that the gas continues to rotate in same way the galaxy does, even after being swept out into space. Furthermore, researchers were able to determine that the rotation of stars in ESO 137-001 remains unchanged. This provides further evidence for the cluster gas, not gravity, being responsible for stripping the galaxy [3].

Matteo Fossati (Universitäts-Sternwarte München and Max-Planck-Institut für extraterrestrische Physik, Garching, Germany) and a co-author of the paper concludes: “With the details revealed by MUSE we are getting closer to fully understanding the processes that go on in such collisions. We see the motions of the galaxy and the gas in detail — something that wouldn’t be possible without the new and unique MUSE instrument. These and future observations will help us develop a better idea of what is driving the evolution of galaxies.”

Notes:

[1] MUSE is the first large integral field spectrograph ever installed at an 8-metre telescope. As a comparison, previous studies of ESO 137-001 collected no more than 50 spectra.

[2] The NASA/ESA Hubble Space Telescope has provided a spectacular image of this object — but, unlike MUSE, cannot reveal the motions of the material.

[3] If gravity were to play a role in the stripping process, the researchers would have expected to see disruptions within the galaxy.

More information:

This research was presented in a paper entitled “MUSE sneaks a peek at extreme ram-pressure stripping events. I. A kinematic study of the archetypal galaxy ESO137-001” to appear in Monthly Notices of the Royal Astronomical Society on 10 November 2014.

The team is composed of Michele Fumagalli (Extragalactic Astronomy Group and Institute for Computational Cosmology, Durham University, United Kingdom), Matteo Fossati (Universitäts-Sternwarte München and Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), George K. T. Hau (ESO, Santiago, Chile), Giuseppe Gavazzi (Università di Milano-Bicocca, Italy), Richard Bower (Extragalactic Astronomy Group and Institute for Computational Cosmology, Durham University, United Kingdom), Alessandro Boselli (Laboratoire d'Astrophysique de Marseille, France) and Ming Sun (Department of Physics, University of Alabama, USA).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1437/eso1437a.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Press release on first light of MUSE: http://www.eso.org/public/news/eso1407/

Hubble imaging of ESO 137-001: http://www.spacetelescope.org/news/heic1404/

Images, Text, Credits: ESO/M. Fumagalli/IAU and Sky & Telescope/Digitized Sky Survey 2/NASA/ESA/CXC/Videos: NASA/ESA/Digitized Sky Survey 2/Acknowledgements: Ming Sun (UAH) and Serge Meunier/ESO/M. Fumagalli/L. Calçada/Music: movetwo.

Best regards, Orbiter.ch

Expedition 41 Departs from Station in Soyuz

ROSCOSMOS - Soyuz TMA-13M Mission patch.

November 9, 2014

Image above: The Soyuz TMA-13M is seen intersecting Earth’s limb several minutes after undocking from the International Space Station. Credit: NASA TV.

After spending 165 days aboard the International Space Station, Reid Wiseman, Alexander Gerst and Maxim Suraev undocked from the station’s Rassvet module at 7:31 p.m. EST to begin their voyage home. Suraev, the Soyuz commander, is at the controls of the Soyuz TMA-13M spacecraft.

They will perform a separation burn to increase the distance from the station before executing a 4-minute, 41-second deorbit burn at 10:05 p.m. The crew is scheduled to land at 10:58 p.m. northeast of Arkalyk, Kazakhstan.

Expedition 41 Crew Heading Home

Video above: Expedition 41 Crew Successfully Departs the International Space Station and heads back to Earth. Video Credit: NASA TV.

The departure of Wiseman, Gerst and Suraev marks the end of Expedition 41. The Expedition 42 crew members, Commander Barry “Butch” Wilmore of NASA and Alexander Samokutyaev and Elena Serova of the Russian Federal Space Agency (Roscosmos) will continue research and maintenance aboard the station.

NASA Television will air live coverage of the Soyuz TMA-13M deorbit burn and landing beginning at 9:45 p.m.

Image above: The International Space Station is seen from the Soyuz TMA-13M spacecraft shortly after undocking at 7:31 p.m. EST Sunday. Credit: NASA TV.

Here is the timeline for the Expedition 41 landing:

EST EVENT

9:45 p.m.                   NASA TV: Expedition 41/Soyuz TMA-13M deorbit burn and landing coverage
10:05 p.m.                 Soyuz TMA-13M deorbit burn (4 minutes, 41 seconds duration)
10:09 p.m.                 Soyuz deorbit burn complete
10:32 p.m.                 Soyuz module separation (altitude 87 miles)
10:35 p.m.                 Soyuz atmospheric entry (altitude 62 miles)
10:44 p.m.                 Command to open parachute (6.6 miles)
10:58 p.m.                 Expedition 41/Soyuz TMA-13M landing northeast of Arkalyk, Kazakhstan

Watch live at http://www.nasa.gov/nasatv.

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

Images (mentioned), Video (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch

Virgin Galactic hopes to resume flights in six months

Virgin Galactic logo.

November 7, 2014

Image above: SpaceShipTwo wreck crashed to the ground in the Californian desert. Image Credits: Reuters / David McNew.

The company of British billionaire Richard Branson hopes to return within six months of test flights, a week after the fatal crash of SpaceShipTwo in the desert.

"It is possible that test flights for the next spacecraft begin within six months before the survey (on accident) does not lead," the company said in an e-mail to AFP. Virgin Galactic is referring here to the investigation by the US Federal Bureau of Investigation on transport accidents (NTSB) after the accident northeast of Los Angeles last week.

Image Above: The NTSB investigators, the US federal agency responsible for investigating accidents in transport, believe that there was a problem with the release of fins on the tail of the shuttle. Image Credits: Keystone / AP.

The SpaceShipTwo spacecraft crashed during a test flight after being separated from its launch aircraft WhiteKnightTwo. The accident resulted in the death of the co-pilot, Michael Alsbury, and seriously injured his pilot, Pete Siebold, while causing questions on the space tourism industry. "The NTSB has informed us that we were free to continue our operations during the investigation. We are thinking about it," says Virgin Galactics.

"Horrible setback"

The new flight test mentioned by the company could be undertaken with a new ship SpaceShipTwo, the company said Tuesday that it was built to "65%". While recognizing that the accident was a "terrible setback" Richard Branson has made it clear he wanted to continue his plan to create the first commercial space transportation line.

Image above: Richard Branson on Tuesday announced the continuation of mounting a second vessel despite the accident that resulted in the destruction of the First Friday and the death of a pilot in the California desert. Image Credits: AFP / Josh Edelson.

The company already has more than 600 customers for future voyages to the edge of space, with a ticket price of 250,000 dollars per person, including celebrities such as actor Leonardo DiCaprio. Virgin Galactic, however, that a "small percentage" of customers had backtracked.

"This small percentage (clients) who requested a refund are great supporters of the project" and their decision is "personal reasons," says the company.

For more information about Virgin Galactic, visit: http://www.virgingalactic.com

Images (Mentioned), Text, Credits: AFP / Translation: Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Mars Spacecraft Reveal Comet Flyby Effects on Martian Atmosphere

 

NASA - MAVEN Mission patch / ESA - Mars Express Mission patch / NASA - Mars Reconnaissance Orbiter (MRO) patch.

November 7, 2014

Image above: Artist’s concept of Comet Siding Spring approaching Mars, shown with NASA’s orbiters preparing to make science observations of this unique encounter. Image Credit: NASA/JPL.

Two NASA and one European spacecraft that obtained the first up-close observations of a comet flyby of Mars on Oct. 19, have gathered new information about the basic properties of the comet’s nucleus and directly detected the effects on the Martian atmosphere.

Data from observations carried out by NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission, NASA’s Mars Reconnaissance Orbiter (MRO), and a radar instrument on the European Space Agency's (ESA’s) Mars Express spacecraft have revealed that debris from the comet added a temporary and very strong layer of ions to the ionosphere, the electrically charged layer high above Mars. In these observations, scientists were able to make a direct connection from the input of debris from a specific meteor shower to the formation of this kind of transient layer in response; that is a first on any planet, including Earth.

Mars Orbiter Observes Comet Siding Spring

Video above: This movie begins with an animation (artist's rendering) of NASA's Mars Reconnaissance Orbiter spacecraft above Mars. The scene zooms into an "X-ray" view of the spacecraft, revealing the High Resolution Imaging Science Experiment (HiRISE) camera.

Comet C/2013 A1 Siding Spring traveled from the most distant region of our solar system, called the Oort Cloud, and made a close approach around 2:27 p.m. EDT within about 87,000 miles (139,500 kilometers) of the Red Planet. This is less than half the distance between Earth and our moon and less than one-tenth the distance of any known comet flyby of Earth.

Dust from the comet impacted Mars and was vaporized high in the atmosphere, producing what was likely an impressive meteor shower. This debris resulted in significant temporary changes to the planet’s upper atmosphere and possible longer-term perturbations. Earth-based and a host of space telescopes also observed the unique celestial object.

“This historic event allowed us to observe the details of this fast-moving Oort Cloud comet in a way never before possible using our existing Mars missions,” said Jim Green, director of NASA’s Planetary Science Division at the agency’s Headquarters in Washington. “Observing the effects on Mars of the comet's dust slamming into the upper atmosphere makes me very happy that we decided to put our spacecraft on the other side of Mars at the peak of the dust tail passage and out of harm's way.”

Images above: Five images of comet Siding Spring taken within a 35-minute period as it passed near Mars on Oct. 19, 2014, provide information about the size of the comet's nucleus. The images were acquired by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Image Credit: NASA/JPL-Caltech/University of Arizona.

The MAVEN spacecraft, recently arrived at Mars, detected the comet encounter in two ways. The remote-sensing Imaging Ultraviolet Spectrograph observed intense ultraviolet emission from magnesium and iron ions high in the atmosphere in the aftermath of the meteor shower. Not even the most intense meteor storms on Earth have produced as strong a response as this one. The emission dominated Mars' ultraviolet spectrum for several hours after the encounter and then dissipated over the next two days.

MAVEN also was able to directly sample and determine the composition of some of the comet dust in Mars’ atmosphere. Analysis of these samples by the spacecraft’s Neutral Gas and Ion Mass Spectrometer detected eight different types of metal ions, including sodium, magnesium and iron. These are the first direct measurements of the composition of dust from an Oort Cloud comet. The Oort Cloud, well beyond the outer-most planets that surround our sun, is a spherical region of icy objects believed to be material left over from the formation of the solar system.

Elsewhere above Mars, a joint U.S. and Italian instrument on Mars Express observed a huge increase in the density of electrons following the comet's close approach. This instrument, the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), saw a huge jump in the electron density in the ionosphere a few hours after the comet rendezvous. This spike occurred at a substantially lower altitude than the normal density peak in the Martian ionosphere. The increased ionization, like the effects observed by MAVEN, appears to be the result of fine particles from the comet burning up in the atmosphere.

Image above: These spectrograms from the MARSIS instrument on the European Space Agency's Mars Express orbiter show the intensity of radar echo in Mars' far-northern ionosphere at three times on Oct. 19 and 20, 2014. The middle plot reveals effects attributed to dust from a comet that passed near Mars that day. Image Credit: ASI/NASA/ESA/JPL/Univ. of Rome/Univ. of Iowa.

MRO’s Shallow Subsurface Radar (SHARAD) also detected the enhanced ionosphere. Images from the instrument were smeared by the passage of the radar signals through the temporary ion layer created by the comet's dust. SHARAD scientists used this smearing to determine that the electron density of the ionosphere on the planet's night side, where the observations were made, was five to 10 times higher than usual.

Studies of the comet itself, made with MRO's High Resolution Imaging Science Experiment (HiRISE) camera, revealed the nucleus is smaller than the expected 1.2 miles (2 kilometers). The HiRISE images also indicate a rotation period for the nucleus of eight hours, which is consistent with recent preliminary observations by NASA’s Hubble Space Telescope.

MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) also observed the comet to see whether signs of any particular chemical constituents stood out in its spectrum. Team members said the spectrum appears to show a dusty comet with no strong emission lines at their instrument’s sensitivity.

In addition to these immediate effects, MAVEN and the other missions will continue to look for long-term perturbations to Mars’ atmosphere.

MAVEN's principal investigator is based at the University of Colorado's Laboratory for Atmospheric and Space Physics in Boulder, and NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the mission. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the Mars Reconnaissance Orbiter. Mars Express is a project of the European Space Agency; NASA and the Italian Space Agency jointly funded the MARSIS instrument.

For more information about NASA's Mars missions, visit: http://www.nasa.gov/mars

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

For more information about NASA's Mars Reconnaissance Orbiter (MRO), visit: http://www.nasa.gov/mission_pages/MRO/main/

For more information about ESA's Mars Express mission, visit: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

Media teleconference visuals: http://www.nasa.gov/mars/telecon/siding-spring-flyby20141107/

Images (mentioned), Video, Text, Credits: NASA/Dwayne Brown/JPL/Guy Webster/Goddard Space Flight Center/Nancy Neal Jones/Elizabeth Zubritsky.

Best regards, Orbiter.ch