The unmannedNASA Mars Climate Orbiter reached Mars and executed a 16 minute 23 second main engine burn on 23rd September 1999 to establish an orbit around Mars at 150km. It orbited behind Mars and was never heard from again.
The Maths Error: Oops! Muddled Units of Length!
The Mars Climate Orbiter, which cost $Aus 136 million, disappeared because a Lockheed Martin engineering team used Imperial measurements while the JPL (Jet Propulsion Lab) team used the more conventional metric system. The wrong navigation information was sent to the Mars Climate Orbiter. It most likely burnt up in the atmosphere.
2nd NASA DISASTER: On 3rd December 1999, the Mars Polar Lander, the sister spacecraft to the Mars Climate Orbiter, crashed on Mars. Units were not believed to be the problem. Total cost of the Mars Program: $ Aus358 million.
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After burning up almost $0.5 billion in crashed/ashed Mars probes, NASA finally hit pay dirt. Unfortunately, the final cost of landing Curiosity on Mars blew the budget $0.9 billion over the budget estimates.
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UPDATE: $2.5 Billion Eagle has Landed
On 6 Aug 2012 NASA landed the plutonium-powered rover the size of a small car called CURIOSITY (pic) on Mars. According to the New York Times the original cost of landing Curiosity on Mars was estimated to be $1.6 billion. But following technical delays and further costs of $0.9 Billion, the rover was finally launched successfully. You can gain an idea of the size of the Mars rover Curiosity from the pic shown from Cosmos Magazine.
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