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Mars Exploration: Where Do We Stand?
Questions are raised after the loss of Mars Climate Orbiter and Mars Polar Lander
by Michelle Evans
Last year was a rough one for the exploration of Mars. The Mars Surveyor 98 program, consisting of two spacecraft, the Mars Climate Orbiter (MCO) and Mars Polar Lander/Deep Space 2 microprobes (MPL/DS2). Both failed upon arrival.
What went wrong and how will these setbacks affect our future exploration of Mars? There is only one solid answer so far and that is what happened to MCO. The use of English instead of Metric numbers when calculating the final insertion into Martian orbit was easily preventable since NASA has insisted for over 20 years that all numbers supplied to them must be in Metric units. The navigation team at the Jet Propulsion Laboratory that oversaw this mission should not be held responsible for the error since it was totally unforeseen on their part.
The outcome of the MCO investigation will insure that contractors fulfill their obligations in the future, while at the same time providing for a proper set of checks and balances so that a mission critical error of this nature can not slip through and again dash our hopes for discovery.
The MPL/DS2 loss may never be completely understood. Since there was no spacecraft telemetry from before the cruise bus separation until the planned touchdown, there are just too many failure modes available to narrow it down with any certainty.
Every communication attempt from Earth met with stony silence, so we have no idea if MPL just landed on a large rock and tipped over or if the spacecraft plunged unchecked through the thin carbon dioxide atmosphere, burning up completely, or left a smoking hole in the rusty soil near the south pole.
Nearly two months after Martian entry, a faint signal on the correct MPL frequency was scoured from the background noise by a team using a radio telescope at Stanford University. This briefly raised hopes that something from MPL was still intact. Did a weak and dying MPL try to phone home? Again, we’ll never know since the signal was never heard again.
All of this is very disappointing but must be taken in the proper context. Mars Surveyor 98 was conceived under the NASA policy called “Faster, Better, Cheaper” (see editorial, page 2). This concept was first proposed by NASA Administrator Dan Goldin and was used to reinvigorate a flagging planetary exploration program.
Instead of one large mission that did everything once a decade, it was hoped that FBC would permit many cheaper and more focused missions every year or two. This has proved to be the case, and in the specific instance of Mars, was off to a flying start with the extremely successful dual mission of Mars Global Surveyor and Mars Pathfinder/Rover which arrived with much fanfare in 1997.
Now there is a major review of the entire FBC program to decide whether it will survive. Hardware already under construction to fly next year has been called into doubt. Will Mars Surveyor 2001 fly?
Right now we still don’t know the answer to that burning question. Time will tell, but launch windows won’t wait.
Our plans of launching probes to Mars every two years to attain a deeper understanding of the red planet was to culminate with a human expedition within the next 15 years or so. If we scale back plans now because of a failure, will bootprints be left in the Martian soil any time in the foreseeable future?
When Dan Goldin started us on the FBC path, he told us right up front that there would probably be some failures along the way; part of the FBC edict was to push the envelope after all. Now that failure has actually occurred. Should we stop now, or do we continue?
Do we learn from our mistakes, or do we let those mistakes defeat us?