鈥淭O LOSE one Martian orbiter may be regarded as a misfortune,鈥� we wrote on 2 October 1999, trotting out the old Oscar Wilde quote. 鈥淭o lose a second looks like carelessness.鈥�
The barb was prompted by NASA鈥檚 second loss of a probe at the doorstep of Mars in six years. 鈥淭he Mars Climate Orbiter was supposed to enter an orbit that would have brought it no closer than 155 kilometres from the surface, after a course-altering rocket burn on 15 September,鈥� we reported. 鈥淭he burn went according to plan. Yet the craft descended to within 57 kilometres of the planet鈥檚 surface, where it could not withstand the friction caused by the Martian atmosphere.鈥� The agency had previously lost contact with its $1 billion Mars Observer probe three days before orbital insertion in 1993.
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We speculated that the two events might be connected. The loss of the Mars Observer had helped drive a switch to cheaper, more frequent missions. 鈥淲e鈥檝e been saying all along they were going to lose one of these things,鈥� said an unnamed NASA scientist after the second incident. Peter Smith at the University of Arizona, principal investigator for the Mars Polar Lander, agreed. 鈥淲ith 鈥榝aster, better, cheaper鈥� you work your people to death,鈥� he said.
Such fears were underlined in our 9 October 1999 issue, which revealed the exact reason for the Climate Orbiter fiasco. It was 鈥渁 result of a mistake that would shame a first-year physics student 鈥� failing to convert Imperial units to metric鈥�, we wrote. Behind this was a clash between spacecraft engineers and navigation specialists, according to NASA spokesperson Mary Hardin. 鈥淧ropulsion people talk in pound-seconds of thrust and navigators talk in newton-seconds,鈥� she said.
The result was erroneous data from the orbiter鈥檚 attitude-control system, which was crucial for guiding the rocket burn. Stressed mission controllers had failed to notice the discrepancy. 鈥淓veryone on NASA projects is incredibly overworked, and mistakes are happening not just because we鈥檙e faster, but because we鈥檙e working nights and weekends,鈥� said Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. Fortunately, subsequent Mars orbiters have made it the final few kilometres.
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