mercredi 3 avril 2013

Used Parachute on Mars Flaps in the Wind












NASA - Mars Reconnaissance Orbiter (MRO) patch.

April 3, 2013

Photos from NASA's Mars Reconnaissance Orbiter show how the parachute that helped NASA's Curiosity rover land on Mars last summer has subsequently changed its shape on the ground.

The images were obtained by the High Resolution Imaging Science Experiment (HiRISE) camera on Mars Reconnaissance Orbiter.

Seven images taken by HiRISE between Aug. 12, 2012, and Jan. 13, 2013, show the used parachute shifting its shape at least twice in response to wind.


This sequence of seven images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter shows wind-caused changes in the parachute of NASA's Mars Science Laboratory spacecraft as the chute lay on the Martian ground during months after its use in safe landing of the Curiosity rover. Image credit: NASA/JPL-Caltech/Univ. of Arizona.

The images in the sequence of photos are available online at http://uahirise.org/releases/msl-chute.php and at http://www.nasa.gov/mission_pages/MRO/multimedia/pia16813.html .

Researchers have used HiRISE to study many types of changes on Mars. Its first image of Curiosity's parachute, not included in this series, caught the spacecraft suspended from the chute during descent through the Martian atmosphere.

Descent of the Phoenix Lander (click on the image for enlarge)

Image above: MRO's HiRISE camera acquired this dramatic oblique image of Phoenix descending on its parachute. Shown here is a a wider view of the full image, showing a 10 kilometer diameter crater informally called "Heimdall" and an improved full-resolution image of the parachute and lander. Image credit: NASA/JPL/University of Arizona.

Although it appears that Phoenix is descending into the crater, it is actually about 20 kilometers in front of the crater. It is difficult to believe that it is in front of the crater because it is so much smaller, but in reality it is, and that's a good thing because landing on the steep rocky slopes of the crater would have been far too exciting (or risky).

Images from the lander clearly show that it sits on a flat plain, although the rim of Heimdall may be visible on the horizon. Given the position and pointing angle of MRO, Phoenix is at about 13 kilometers above the surface, just a few seconds after the parachute opened. This improved image shows some details of the parachute, including the gap between upper and lower sections. At the time of this observation, MRO had an orbital altitude of 310 kilometers, traveling at a ground velocity of 3.4 kilometers/second, and a distance of 760 kilometers to the Phoenix lander.

Mars Phoenix Lander. Image credit: NASA / JPL-Caltech

The image was rotated to a position that seems approximately parallel to the horizon based on the elongation of Heimdall Crater, but this is not exact. Thus, although Phoenix appears to hang from the parachute at an angle, as if swaying in the wind, the exact geometry has not yet been determined. The parachute image is very sharp as its apparent motion was straight down the HiRISE TDI (time delay integration) columns. However, the surface of Mars was moving at an angle to the TDI columns, and thus is smeared by a few pixels, although the smear is not apparent at the reduced scale of the image shown here.

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project and Curiosity are managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena.

For more information about the Mars Reconnaissance Orbiter, which has been studying Mars from orbit since 2006, visit http://www.nasa.gov/mro

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

Cheers, Orbiter.ch