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

Late Breaking News:

[TripMaster Monkey]

Today the Council disclosed the news that the repulsive beings inhabiting the blue planet third from our star have located the wreckage of one of their invading spacecraft near our planet's southern pole.

Strangely enough, their newscasts mentioned nothing of the warning plaque errected alongside the downed invader.
Some scientists theorize that the translation of our warning into their bestial language was imperfect, while others maintain that the plaque is simply too small to be imaged properly with their feeble, childish astronomical instruments.

K'Breel, speaker for the Council, voiced another, more pesimistic theory:

"Certainly, beings who are capable of constructing and sending such fiendishly clever little devices to spy on our world are more than capable of receiving and understanding our warning. They have simply chosen to disregard it. Clearly we can no longer ignore the predaceous advances of the evil blue planet. The Council has given the final authorization to divert our asteroid into a collision course. We now need only wait."

A proposal

[JPelorat]

Change the project name to

Mars Polar Plummeter

and call it a "smashing success"!

Re:A proposal

[deglr6328]

The parachutes worked fine. The crash was caused by a tiny microswitch on one of the landing feet that was supposed to switch the engines off when it was clicked shut by touching rocks/dirt. It bounced shut 40M up because that's when the feet unfolded causing a slight jolt to the craft. No one anticipated that and the software was designed ONLY to say: switch closed=shut down engines now!

Before it gets Slashdotted...

[TripMaster Monkey]

Here's the text of the article:

In December 1999 NASA's Mars Polar Lander (MPL) was supposed to touch down near the red planet's south pole. But shortly after it entered the Martian atmosphere, the spacecraft disappeared without a trace. Only now, 5½ years later, do scientists think they may have finally located the lander's wreckage and confirmed what went wrong with the mission. The full report, by planetary scientist Michael C. Malin (Malin Space Science Systems), appears in the July 2005 issue of Sky & Telescope, now in press.

Malin used his company's Mars Orbiter Camera (MOC) aboard NASA's Mars Global Surveyor to search for the missing spacecraft in late 1999 and early 2000, but apparently came up empty. Shortly thereafter, a review board looking into the craft's disappearance reported what might have caused Mars Polar Lander's demise. The board suggested that MPL's landing rockets fired at the right time and altitude but cut off prematurely. They were suppose to continue firing until one of the craft's landing legs touched the surface. Apparently the onboard software mistook the jolt of landing-leg deployment for ground contact and shut down the engines, causing MPL to fall from a presumed height of 40 meters (130 feet).

Using information gained from observing the two Mars Exploration Rover landers last year, Malin reexamined the 1999 and 2000 images looking for similar features. This time he identified what looks to be a parachute located several hundred meters away from a disturbed bit of ground with a large mark in its center. The parachute-like feature closely matches the Mars Exploration Rover parachutes (which were made of the same materials), and Malin believes the disturbed ground matches what one would see if a rocket had blasted the surface from a height of tens of meters.

"It seems that the MPL investigation board may have been correct," writes Malin in Sky & Telescope. "MPL's descent proceeded more or less successfully through atmospheric entry and parachute jettison. It was only a few short moments before touchdown that disaster struck."

Later this year NASA will direct Mars Global Surveyor to reexamine the MPL crash site using a special technique to improve the camera's resolution to 0.5 meter per pixel. Malin hopes the new observations will provide the conclusive evidence needed to officially close the case of the missing Mars Polar Lander.

Here's the photo in case of Slashdotting

[WormholeFiend]

Photo: .

Enlarged: o

Obligatory Link to the Lobbing Scorecard

[Old VMS Junkie]

For those of you keeping score in the grand game... http://www.bio.aps.anl.gov/~dgore/fun/PSL/index.ht ml

Direct link to data and photos at Malin Space

[CuriousKangaroo]

Here is the direct link to the Malin Space Science Systems page with the data and images.

In addition to MPL, they have found Viking 2.

http://www.msss.com/mars_images/moc/2005/05/05/ind ex.html

Cool stuff.

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.