by Bruce Moomaw
Cameron Park - April 17, 2000 - You don't have to be Sherlock Holmes to conclude that short changing planetary exploration would lead to massive cuts in both the project staffing and the testing that had made earlier JPL missions successful.
Moreover these cuts were responsible for the failure to detect the missions' fatal flaws, as well as for a whole parade of other serious design and testing flaws that might also have ruined the missions.
The Polar Lander review board concluded that the whole Mars '98 program was underfunded by at least 30% -- and also that the Lander, at least, would have required a full-size Delta booster (rather than the smaller "Medlite Delta" ordered by NASA Headquarters) to provide a big enough margin to incorporate the weight increases which the lander would inevitably undergo in order to properly correct problems discovered during its design and testing.
What the review boards left unanswered was where the blame for that initial ridiculous underestimate of the project's cost lies.
It may have been due to a peremptory demand by NASA's rather authoritarian Administrator Daniel Goldin; but there are also rumors that -- after the failure of Mars Observer -- JPL and Lockheed Martin were both afraid that they would lose their dominance of the new "Faster-Better-Cheaper" planetary program, and submitted seriously understated cost estimates in order to retain a lock on deep space exploration.
So now what?
The 2001 Orbiter will definitely go up on schedule in April 2001; it's a near-twin of Mars Climate Orbiter, but all indications are that MCO would have worked well if its controllers hadn't flown it into the planet due to an undersized navigational staff -- and the 2001 Orbiter carries two instruments which are very important in selecting promising future landing sites to look for evidence of life.
The 2001 Lander, though, is a different matter.
A whole series of serious flaws was found in its design that could have ruined it, besides the touchdown-contact switch problem that would have done so in any case.
The next Mars lander will fly in 2003 at the earliest, with significant changes -- including an enlarged communications system to allow engineering telemetry during the landing itself, and also a direct backup communications link to Earth after the landing (which existed on Polar Lander, but had been cut out of the 2001 Lander on the confident assumption that both the Mars Climate Orbiter and the 2001 Orbiter would be available to serve as relay comsats).
This by itself will add about 30 kg to its weight -- and other major changes may also be necessary.
The Failure Board found another serious problem that may very well have caused the Lander to fail before its touchdown-switch problem even got a chance to do so: its "pulse-mode" clusters of fixed-thrust rocket engines -- which were chosen to minimize the cost of the engines themselves -- had the potential to produce serious stability problems, and perhaps even fuel-line ruptures, during the descent. The Board flatly recommended that they be replaced by throttleable rocket engines on future landers.
And -- given the hazards of Mars' own rugged terrain -- both a computerized landing-obstacle avoidance system and stronger (and heavier) landing gear may be advisable.
The Lander is already largely built; its avionics and scientific instruments will probably be used at some point -- but it is by no means certain that it will ever fly.
That decision must be made within a month or so.
And if it does fly, its primary landing site has already been changed from the Libya Mountains south of the Isidis Plain to the famous "Hematite Area" discovered by MGS in the Sinus Meridiani that was its former backup landing site.
Project scientist Steve Saunders told SpaceDaily that this region looks smoother than the Isidis site, and that "scientific interest in it is growing."
It may very well be a layer of ancient lake-bottom sediments that was buried by wind-blown material after Mars became hostile, and has been uncovered again only fairly recently -- and this could make it one of the best above-ground surfaces of present-day Mars to look for preserved fossil or chemical evidence of ancient life.
But with some 4-5 years before that lander touches down, additional analysis of photos from MGS currently in orbit may lead to the landing site being changed again.
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.|