NASA's Mars Polar Lander Found at Last?

Ant wrote in to mention that the Sky and Telescope is running a story (with photographs and other images) that NASA's Mars Polar Lander (MPL) may have been found. From the article: "On December 9, 1999, it was supposed to touch down near the red planet's south pole but disappeared after entering the Martian atmosphere without a trace. 5.5 years later, scientists think they may have finally located the lander's wreckage and confirmed what went wrong with the mission...The search for Mars Polar Lander was hampered by inexperience: the team didn't know what a parachute should look like or how the ground would be disturbed by the landing rockets. Lessons learned from observations of the Mars Exploration Rover landing sites helped team members identify what they think are the parachute, the rocket-blast zone, and ultimately the lander itself."

Comments

Re:Can't Wait

[TGK]

Some countries have signed treaties saying they won't claim/weaponize space. Of course, some of those same countries signed treaties saying they wouldn't try to develop anti-ballistic missiles.

Under international law (specificly the treaty of London, 1600) a settlement, colony, or claim is only valid if the country in question has the means in palce to defend it.

In other words, should China (which didn't sign that whole "won't claim space" treaty) land on the Moon and claim it for China, it won't be recognised as Chinese property unless they bring along some effective means of keeping other people off of it.

Functionaly this leads to an anarchical environment. Wasn't such a bad idea in the 1600s, but when you're talking about the idea of carpet nuking someone's moon base into smoking oblivion to invalidate their claim to the place... well... things are different.

Why the MPL crashed

[photonic]

I did read the failure investigation report (can be found here, search for polar) some time ago and IIRC the most probable failure scenario was a software error involving a single boolean:

MPL was to land under active control (with rocket power, not the air-bag trick). To kill the moter once it had touched down the legs contained contact sensors which were constructed of a pin with a spring, a magnet and a Hall-sensor. The legs were to be extended some time before touchdown.

The problem was the sensors would trigger some intermediate false readings during the leg extension. These false readings toggled a flag, which, once the control system first started looking for contact, immediately killed the engine, having the lander free-fall to death. Clearing the flag after the leg-extension would have saved the mission. The bug was not found because of errors in the software design documents and lack of a system level test. The intermediate false readings were found in a component level test, but its consequences somehow didn't made it in the final design.