by Mike Hegg
Sometimes, rookie mistakes can lead to professional screw-ups, as the world witnessed last Friday, Oct. 1st, when an $125million U.S. space probe was incinerated in the Martian atmosphere. The Mars Explorer, a product of Lockheed Martin Astronautics in Colorado, was set to orbit the planet and study the chemical properties of the Martian atmosphere when it flew too close to the planet due to an error in the thrust calculations and burnt up. What is so startling about the incident is how and why it occurred. According to a statement issued by JPL (Jet Propulsions Laboratory), the team from Lockheed Martin used acceleration data in pounds of force. NASA assumed the data was actually in metric Newtons, the more common unit used in astronautical engineering and so the thrust data for the space craft was off by a factor of 2.5 or more. The thrusters on the spacecraft are typically utilized for in-flight corrections to trajectory, orbital velocity etc. H.T. Williams, professor of physics at Washington and Lee University, wonders whether or not the "rookie mistake" was actually a complex screw-up. "One question must be asked, and that is, why does Lockheed use English units and NASA metric units? One plausible explanation might be that Lockheed was using old thrust data from around 20 years ago, when all calculations were done in English units." Still, there is no excuse as to why error checks by NASA failed to notice the discrepancy. " The conversion from English to Metric units is a simple one and because of this, I wonder whether or not there was a more complex mistake involved " said Williams. Two separate review committees are being organized to investigate the mistake.
Sources:
USA TODAY, Friday, Oct. 1st
Interview: H.T. Williams.