NASA Reveals Probable Cause of Mars Polar Lander and Deep Space-2 Mission Failures.

MPL The Mars Polar Lander's December 1999 demise apparently occurred when the lander thought the jolt of its landing leg deployment was touchdown - and shut its engines off. Moments later it crashed into Mars at freeway speed, the second probe to do so in less than 4 months. The two Deep Space-2 probes, (ironically) designed to intentionally crash into Mars at 400 miles per hour, also vanished without a trace. The teams investigating that loss suggested simply that the DS-2 probes should not have been launched since they were not ready to be launched in the first place.

NASA announced the results of its Mars Polar Lander investigation team's report to a packed auditorium at NASA headquarters. The briefing was presented by NASA Associate Administrator for Space Science Ed Weiler, and Tom Young, the head of the Mars Program Independent Assessment Team. Both Young and Weiler looked like they'd rather have been somewhere else. In addition to the Young Team's report, the "Report of the Loss of the Mars Polar Lander and Deep Space 2 Missions" by the JPL Special Review Board (aka the Casani Report) were also presented. The chair of that team, JPL's John Casani, did not make a presentation or answer questions during the formal briefing.

The conclusions reached by the team were the result of detective work and post-crash testing and analysis. Since there was no telemetry capability from the MPL during atmospheric entry, descent, or landing, there can be no way to know for sure exactly what happened. While a number of failure scenarios were examined, a specific candidate failure scenario emerged - one borne out by repeated ground-based, post-failure testing.

Four tests in early 2000 by Lockheed Martin in Denver showed that sensors in the MPL's landing gear sent out spurious signals. Software that should have been designed to ignore these signals was not designed to do so after all. These signals were interpreted by the spacecraft as being indicative of the forces landing legs would experience upon landing and the descent engines were shut off. This design flaw was not caught before launch since a series of tests used sensors that were wired incorrectly. Ergo, the problem was not detected, and Mars Polar Lander was sent on a doomed flight to Mars.

Again, while there is no way to be certain that this flaw was the actual cause of the MPL failure, Young said that the team was more or less certain that the engines were shut off at an altitude of 40 meters and that the MPL crashed into the Martian surface at 22 meters per second (50 miles per hour). Meanwhile the team found that the twin DS-2 microprobes had not been tested enough and were "not ready for launch".

Faster-Better-Cheaper came up several times. Weiler and Young both defended the concept as basically sound and did not recommend that it be abandoned. However Weiler said that clearly NASA had "pushed the envelope to far" in part, buoyed by the Mars Pathfinder and Mars Climate Orbiter missions. Weiler admitted that it is now time to reconsider the envelope, pull back, and regroup.

The team ascribed the cause of these twin disasters as being due to ineffective communication between NASA headquarters and JPL and between JPL and Lockheed Martin. Moreover, the mission team was asked to do the impossible with a budget that, in retrospect, the team feels was 30% less than it should have been. Weiler cited the lack of adequate reserves - and the fact that all program funds should not have been sent to the centers as contributing managerial causes. Weiler said he now favors keeping reserve funds at headquarters such that program managers at the field centers need to come to headquarters when something is about to go wrong with their program. This would be in contrast with Dan Goldin's push to distribute as much responsibility and oversight as possible to the field centers.

As a result of its findings, the team recommended a series of management changes in NASA's Mars Program. In concert with the release of the report, Ed Weiler announced that Scott Hubbard from NASA ARC would be come the new single point of contact for all NASA Mars exploration at NASA Headquarters. JPL center director Ed Stone was expected to make an announcement regarding a single point of contact at JPL for Mars. Other than the extended leave of absence being taken by former NASA HQ Mars coordinator Carl Pilcher, and Hubbard's apparent assumption of Pilcher's previous responsibilities, no one seems to have been fired - nor will they according to Weiler. Nor is any one to be blamed.

Instead, Weiler seeks to fix management problems with new focused management and training. Weiler also spoke of enhancing the training of its employees at JPL, of enhancing mentoring such that experienced personnel are linked up with newer hires to facilitate the transfer of experience instead of expected folks to figure it out on their own. He also spoke of an increased need to facilitate communication from all levels of the program such that problems can be surfaced in a non-adversarial environment. To this end he and Dan Goldin will be spending more time talking to middle- and lower level management.

Weiler has initiated a sweeping re-look at NASA's Mars Exploration program, one where only the budget is fixed. All other bets are off and all ideas are welcome. A few details have already been decided: the Mars 2001 Orbiter will proceed as planned while the 2001 lander will not. However, the science hardware that was to have been on the 2001 lander will be completed and the hardware will be used on later Mars missions.

Weiler said that this Mars Plan would have its goals refocused - with the main goal being the "search for past and/or current life on Mars'. The main paradigm for this search would be to "follow the water" since water is pivotal to life as we know it. Since it seems that much of Mars' early water inventory is now sequestered underground, Weiler said "we may need to bring drills to Mars at some point". Weiler also seemed to be suggesting that the stopping point of sample return might now longer be the end point and that more expansive activities might be considered noting that this plan would be one "covering a decade, not just 5 years." Just what that might be was not spelled out.

When asked to comment on Lockheed Martin's culpability, Tom Young dodged the question and said simply that the team had not been asked to look into this and that it was "NASA's business" how they managed Lockheed Martin. Young did place a clear amount of blame on Lockheed Martin and did not disagree with the characterization made by a CNN reporter that these mistakes (on MPL and Mars Climate Orbiter) seemed to be "stupid". Weiler responded later that "all mistakes are stupid in hindsight". Young also suggested that the lack of cost realism was due in part to an "aggressive proposal" by Lockheed Martin. In layman's terms, this means they bid too low and made too many optimistic assumptions in the short run - and it came back to bite them in the long run.

Tom Young's role in this report - and his previous senior position at Lockheed Martin was raised - including the perception of a conflict of interest. He noted that he had left Lockheed Martin 5 years earlier, that he had a lot of eyes watching the whole process, and NASA knew his background from the beginning. He compared his relationship to Lockheed Martin and its problems now as being that of a doctor to a close friend "the worst thing you can do [as a doctor] is not to tell them that they are sick".

When asked when he first noticed problems, Ed Weiler reminded everyone that when he became Associate Administrator, "both MCO and MPL were on the launch pad". None the less, he said that he said that he began to sense problems with NASA's programmatic approach to Mars when he saw that the Mars Sample Return mission, still in early development, only had 10% reserves in place. He added that his concern for lack of realism vis a vis reserves led him to cancel the Champollion mission - one that had 20% reserves built into the budget.

Weiler also addressed the issue many have asked - why a proven landing technology such as that used on Mars Pathfinder (air bags) was not used again on MPL. The answer was simple - MPL was already too far along in its design to benefit from the results of Pathfinder. He left open the possibility that air bags or some variation thereof might be used again. Weiler then said "I cannot tell you how we'll land the next time we land on Mars."

When asked where Dan Goldin was and what he had to say about the report, Tom Young recounted the meeting he had with Goldin, the fact that Goldin had not pressed him for results, and that Goldin was briefed just before OSTP received a preview of the report last week. Other than that , Goldin's absence was not explained, nor was any note made as to when he'd have something to say on the topic.

Background Information

Report of the Loss of the Mars Polar Lander and Deep Space 2 Missions -- JPL Special Review Board (Casani Report) (acrobat)
Parts [1] [2] [3] [4] [5]
Mars Program Independent Assessment Team (Young Report) (Acrobat) Summary Report; Full Report parts [1] [2]
NASA Press Release
Mars, SpaceRef Directory
Whole Mars Catalog, Space Ref
Focus on Mars Polar Lander, SpaceRef


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