Saturday, August 25, 2012

Mars Science Laboratory Beams Back Landing Video

The HIRISE spacecraft photographed MSL as it was parachuting down to
the Martian surface. Credit: NASA.
I haven't posted about the Mars Curiosity rover yet, because it has been thoroughly covered by other news sources and I've just been enjoying reading about all of its success so far. However, NASA just released the video of Curiosity's descent, as viewed from the spacecraft itself. It is pretty incredible to see such high quality video of the fantastic landing, which was a feat of creativity, sophisticated software, and brilliant systems integration.

Mike Wall, from, describes what you will see in the video:
The high-definition video chronicles the final 2.5 minutes of Curiosity's 7-minute plunge through the Martian atmosphere in real time, starting just after the rover jettisoned its heat shield. The first few seconds show the heat shield falling away toward the red dirt of Gale Crater far below. 
Other milestones follow, such as parachute deploy and ignition of the engines on Curiosity's "sky crane" descent stage, which lowered the 1-ton rover to the Martian surface on cables. Audio from mission control at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., plays over the video, describing the nail-biting action
As Curiosity nears the Martian surface, huge dust clouds billow around the $2.5 billion robot, kicked up by the sky crane's rockets. Then the view clears to show a close-up, static shot of scattered pebbles.

If you haven't seen it yet, watch 7 Minutes of Terror, the movie trailer-esqu video simulation of the landing sequence before watching the real thing.

7 Minutes of Terror:

Real video of MSL descent:

Sunday, August 19, 2012

Proba-1 is Back in Business.

ESA's Proba-1 microsat was built and launched by the ESA as a proof-of-concept for semi-autonomous Earth observation - operators can upload coordinates and the satellite will autonomously image that location. The satellite ended up turning into a heavily-used science tool, but it almost shut down in May due to star tracker degradation. 

Proba-1 captured this image of London's Olympic Park
 neighborhood.   Credit: ESA 
Many small satellites use star trackers to orient themselves. The star trackers point behind the satellite (away from the Sun and Earth) and take pictures of star fields, which they can identify and use to calculate the satellite's orientation.  The CCD camera's attached to Proba-1's star trackers had sustained severe radiation (they were 5 years older than the planned lifetime for Proba-1), and the radiation had created permanent damaged or "hot" pixels which  show up in images as white spots. The star trackers were mistaking hot pixels for stars, and sending incorrect coordinates to the main satellite computer, causing it to error out or mispoint. 

Proba-1 was saved by a software patch written specifically for the satellite, which - once loaded - allowed the star trackers to distinguish between hot pixels and real stars. The star trackers are apparently working "as good as new" now, even with degraded CCDs. The proof is in the pudding - at the right is a farewell shot of Olympic Park that the satellite shot last week.