THE keystone of NASA鈥檚 ambitious exploration of Mars, a mission to get
samples back from the planet by 2008, will probably be delayed. The space agency
will have to draw up a new timetable as it reviews the loss of two Mars missions
last year and the publication last week of a highly critical report from
independent assessors of the Mars programme.
At a press conference in Washington DC to release the report, NASA space
science chief Ed Weiler announced the cancellation of plans to launch a Mars
lander next year. But NASA will go ahead with an orbiter in 2001 to study
surface composition and look for signs of water. The space agency will now take
several months to rethink its Mars programme. The delay in launching the 2001
lander 鈥済ives them the breathing room they need to work out a sensible
programme鈥�, says Peter Smith of the University of Arizona, principal
investigator on the failed Polar Lander.
The assessment panel, headed by Thomas Young, a retired Lockheed Martin
executive, blames last year鈥檚 losses of the Mars Climate Orbiter and Polar
Lander on poor management, inadequate budgets and overstressed staff. He says
that pressure to cut costs meant staff took short cuts in testing, engineering
and management, which greatly increased the risk of failure. The two missions
were 鈥渦nderfunded by at least 30 per cent鈥�, says Young. 鈥淚 pushed too hard and
in so doing, stretched the system too thin,鈥� says NASA administrator Dan
Goldin.
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The Young panel blames the demise of the Polar Lander on faulty sensors and
software which combined to shut down the descent engines too early, while the
craft was still 40 metres above the ground. The sensors misread vibrations from
deploying the three landing legs as the shock of touching down, and software
failed to spot the error. The panel could not be sure what went wrong with the
two Deep Space 2 probes which were supposed to detach from the Lander during
descent and penetrate the Martian surface. But Young says testing was so
inadequate, 鈥渢he probes actually were not ready for launch鈥�.
Because work on the 2001 lander is well advanced, Weiler says 鈥渨e will
complete all the scientific instruments and avionics鈥� and launch them on future
landers. He pledged more resources for future missions, and raised next year鈥檚
Mars budget by $20 million to a total of $250 million. Weiler also
named Scott Hubbard鈥攑raised for his role in planning the successful Mars
Pathfinder mission鈥攁s the new director of the Mars programme at NASA
headquarters.
One of Hubbard鈥檚 first tasks will be to devise a coherent strategy for the
Mars programme, focusing on hunting down evidence of past or present life on
Mars, with water a particular target. But, with launch windows only every two
years and the next lander not due for launch until 2003, the mission to bring
back samples is likely to slip from its planned launch in 2005.
NASA鈥檚 changes are getting mixed reviews. 鈥淭hey鈥檙e on the right track,鈥� says
Howard McCurdy, a space historian at American University in Washington DC who
believes NASA needs to abandon elaborate management styles it inherited from the
aerospace industry. But one scientist wondered how much of the enlarged Mars
budget would finance the plethora of failure review panels.