vendredi 21 septembre 2018

NASA’s MAVEN Selfie Marks Four Years in Orbit at Mars













NASA - MAVEN Mission logo.

Sept. 21, 2018

Today, NASA’s MAVEN spacecraft celebrates four years in orbit studying the upper atmosphere of the Red Planet and how it interacts with the Sun and the solar wind. To mark the occasion, the team has released a selfie image of the spacecraft at Mars.

“MAVEN has been a tremendous success,” said Bruce Jakosky, MAVEN principal investigator from the University of Colorado, Boulder. “The spacecraft and instruments continue to operate as planned, and we’re looking forward to further exploration of the Martian upper atmosphere and its influence on climate.”


Image above: This image is a composite selfie taken by MAVEN's Imaging Ultraviolet Spectrograph (IUVS) instrument that normally looks at ultraviolet emissions from the Martian upper atmosphere. Lines are sketched in to show approximately where components of the spacecraft are that were not able to be imaged due to the limited motion of the instrument around its support boom. Thrusters can be seen at the lower left and right, the Electra communications antenna at the bottom toward the left, the magnetometer and sun sensor at the end of the solar-panels at the upper left, the tip of the communications antenna at the top middle. In addition, the shadow of the IUVS and of its support boom can be seen down the middle of the spacecraft body. Image Credits: University of Colorado/NASA.

MAVEN has obtained a selfie image, looking at ultraviolet wavelengths of sunlight reflected off of components of the spacecraft. The image was obtained with the Imaging Ultraviolet Spectrograph (IUVS) instrument that normally looks at ultraviolet emissions from the Martian upper atmosphere. The IUVS instrument is mounted on a platform at the end of a 1.2-m boom (its own “selfie stick”), and by rotating around the boom can look back at the spacecraft. The selfie was made from 21 different images, obtained with the IUVS in different orientations, that have been stitched together.

The mission launched on Nov. 18, 2013, and went into orbit around Mars on Sept. 21, 2014. During its time at Mars, MAVEN has answered many questions about the Red Planet.


Image above: This image identifies the various parts of the MAVEN spacecraft selfie, with an artist's sketch of the spacecraft for comparison. Individual components are identified in both the selfie and the computer image. Notice that the computer-generated image shows the IUVS instrument, but that it is not visible in the actual selfie (because that’s what’s taking the picture!). Image Credits: University of Colorado/NASA.

The spacecraft has made the following discoveries and science results, among others:

- Acquired compelling evidence that the loss of atmosphere to space has been a major driver of climate change on Mars.

- Determined that the stripping of ions from the upper atmosphere to space during a solar storm can be enhanced by a factor of 10 or more, possibly making these storms a major driver of loss of the atmosphere through time.

- Discovered two new types of Martian auroras – diffuse aurora and proton aurora. Neither type has a direct connection to the local or global magnetic field or to magnetic cusps, as auroras do on Earth.

- MAVEN has made direct observations of a metal-ion layer in the Martian ionosphere, the first direct detection on any planet other than the Earth. The ions are produced by a steady influx of incoming interplanetary dust.

- Demonstrated that the majority of the CO2 on the planet has been lost to space and that there isn’t enough left to terraform the planet by warming it, even if the CO2 could be released and put back into the atmosphere.

Next year, engineers will initiate an aerobraking maneuver by skimming the spacecraft through Mars’ upper atmosphere to slow it. This will reduce the highest altitude in MAVEN’s orbit to enhance its ability to serve as a communications relay for data from rovers on the surface. Currently, MAVEN carries out about one relay pass per week with one of the rovers. This number will increase after NASA’s InSight mission lands on Mars in November.


Image above: This image shows part of the MAVEN spacecraft and the limb of Mars in the background. This is one of the individual images that make up the selfie, showing the magnetometer and sun sensor at the end of the solar panel. Mars is seen in the background; the dark spot at the top of the image is the Olympus Mons volcano. Image Credits: University of Colorado/NASA.

MAVEN completed its primary mission in November 2015 and has been operating in an extended mission since that time, continuing its productive investigation of Mars’ upper atmosphere and exploring additional opportunities for science that the new relay orbit will bring.

MAVEN’s principal investigator is based at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN project and provided two science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. The University of California at Berkeley’s Space Sciences Laboratory also provided four science instruments for the mission. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides navigation and Deep Space Network support, as well as the Electra telecommunications relay hardware and operations.

For more information on the MAVEN mission, visit: https://www.nasa.gov/maven
and http://lasp.colorado.edu/home/maven/

Images (mentioned), NASA/Karl Hille/GSFC/Nancy Jones.

Greetings, Orbiter.ch