View Full Version : What ever happened to the mars polar lander?

2003-May-30, 04:02 AM
All i know is that they lost contact on dec3/99 upon entry and were unable to ressume communications.
I heard that the mars orbiter cameras dotn have the resolution to visually spot the lander.

Anybody heard anything more? Any ideas on what happened? Fell thru a crust of dry ice? Something intigral broke on impact? Eaten by martians?

2003-May-30, 05:52 AM
As I recall they decided it was most likely a faulty ground-contact sensor or something like that. The lander thought it was on the ground and shut its engines off early. After that... it probably was not a pretty landing. :(

2003-May-30, 08:01 AM
I seem to remember the same thing.

After a bit of googling, this site (http://spaceflight.nasa.gov/spacenews/releases/2000/mpl/mpiat_report_1.pdf) turned up (large PDF file). Page 20ish has the exact quote of the conclusion reached by the investigators if you want to see it.

I was a high school senior when that happened. We were all a little disappointed, especially since it came not long after the loss of the climate observer mission.

2003-May-30, 02:52 PM
I seem to remember the same thing.

After a bit of googling, this site (http://spaceflight.nasa.gov/spacenews/releases/2000/mpl/mpiat_report_1.pdf) turned up (large PDF file). Page 20ish has the exact quote of the conclusion reached by the investigators if you want to see it.

If I remember correctly, there was a spurious signal from the touchdown sensor triggered when the landing legs deployed. The software mistakenly took this to mean the lander had touched down and terminated engine thrust. MPL smacked into the surface and probably broke apart.

Along with the paper above, this paper (http://spaceflight.nasa.gov/spacenews/releases/2000/mpl/mpl_report_1.pdf) goes into more detail.

2003-May-30, 03:26 PM
There was a spurious report a few years back that Naitional Imagery & Mapping Agency was testing out a way to get higher resolution images of the ground from space. By capturing multiple fast images and then combining them while taking the motion of the spacecraft and the pixelization of the sensor into account, you could increase the image resolution an order of magnitude or more.

NIMA supposedly tested it out with the current Mars orbiter, and captured an image of the Polar lander intact and sitting safe on the ground.

The story then evaporated and was never heard again.

Space.com still has a link, though it doesn't mention much about the imaging methodology.

I used to have a great link that explained the image enhancement, but have lost it. Technically, it's something you could do with any digital imaging system.


2003-Jun-01, 06:54 AM
It was a design flaw that should have been found in integrated systems testing, but poor management cut the integrated testing.

The landing legs were designed to deploy while the lander was still at some altitude over the surface. The thrusters would slow and guide the lander to the surface. Upon contact with the ground, the lander legs would trip switches to cut off the thrusters. In theory, a good idea. However, when the landing legs deployed, they overran the proper position and triggered the limit switches, shutting off the thrusters while still in the air at altitude. Thus the lander performed an unplanned impact test instead.

2003-Jun-01, 08:29 PM
Which one was the one that failed to reach Mars orbit due to an English/SI units problem?

2003-Jun-01, 09:11 PM
That was the Mars Climate Orbiter (http://mars.jpl.nasa.gov/missions/past/climorb.html). More detailed analysis here. (http://www.space.com/news/mco_report-b_991110.html)

Basically, the commands sent to the orbiter weren't affecting it the way they though, so when it reached Mars the aerobraking part of entering orbit was performed way too low, and it burned up. :(

Yeah, the 90's weren't kind (http://www.iki.rssi.ru/mars96/mars96hp.html) to missions (http://www.space.com/scienceastronomy/solarsystem/marsmissions_991020.html) to mars. OTOH, you have to try to fail. Next at the plate is (I believe), the Japanese Nozomi (http://www.isas.ac.jp/e/enterp/missions/nozomi/index.html) (Planet-B (http://www.planet-b.isas.ac.jp/index-e.html)) orbiter.