Lou, IMHO, the "poor management" problem does not only belong to NASA, also to the senate committee. The committee should help NASA improve their Verification and Qualification procedure.
Not long ago NASA had a failed mission due to a design mistake omitting transition unit for propelling force in Pound to Kilogram. Pretty soon they had the second failed mission. This time it is because "The software ... was not properly implemented" (see the NASA report below). Are all these overlook mistakes are forgivable to taxpayers? Barry Ma b...@anritsu.com ---------- Original Text ---------- From: "Lou Gnecco" <l...@tempest-inc.com>, on 3/30/00 2:20 PM: Sen. McCain is on the committee that oversees NASA. He recently said that the basic problem is poor management. IMHOP he's right. lou -------------- Scott Lacey Below is an excerpt from the complete NASA report. <<Premature shutdown of descent engines. PLAUSIBLE. A magnetic sensor is provided in each of the three landing legs to sense touchdown when the lander contacts the surface, initiating the shutdown of the descent engines. Data from MPL engineering development unit deployment tests, MPL flight unit deployment tests, and Mars 2001 deployment tests showed that a spurious touchdown indication occurs in the Hall Effect touchdown sensor during landing leg deployment (while the lander is connected to the parachute). The software logic accepts this transient signal as a valid touchdown event if it persists for two consecutive readings of the sensor. The tests showed that most of the transient signals at leg deployment are indeed long enough to be accepted as valid events, therefore, it is almost a certainty that at least one of the three would have generated a spurious touchdown indication that the software accepted as valid. The software - intended to ignore touchdown indications prior to the enabling of the touchdown sensi! ! ng logic - was not properly implemented, and the spurious touchdown indication was retained. The touchdown sensing logic is enabled at 40 meters altitude, and the software would have issued a descent engine thrust termination at this time in response to a (spurious) touchdown indication. MOST PROBABLE CAUSE OF LOSS OF MISSION>> ____________________________________________________________________ For the largest MP3 index on the Web, go to http://mp3.altavista.com ____________________________________________________________________ ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
