NASA, SpaceX Work to Fix Anomalies from Last Dragon Cargo Flight

[Buster's Uncle]

NASA, SpaceX Work to Fix Anomalies from Last Dragon Cargo Flight
By Mark Whittington | Yahoo! Contributor Network – 19 hrs ago.. .


 Though the first operational cargo mission for the SpaceX Dragon to the International Space Station was ultimately successful, a number of problems cropped up during the flight have both NASA and SpaceX concerned.
 
Marcia Smith has written a piece on SpacePolicyOnline.com about some of the problems being worked on.
 
Engine failure most prominent problem during Dragon's flight

According to CNN, the Falcon 9 launch vehicle that boosted the Dragon into low Earth orbit lost one of the nine Merlin engines that power the first stage. The Falcon 9, though, was able to adjust, due to a cross feed design, and achieve orbit using the other eight engines. This was the same capability that the Saturn V had, which was of use when it suffered an engine failure during two of its launches, including the one that launched Apollo 13.
 
Computer and other anomalies noted

Smith's article noted that one of the three computers on the Dragon failed when it "de-synched" with the other two. The Dragon is able to operate on two computers, so the decision was made not to try to fix the malfunctioning computer on orbit. Engineers suspect that the computer was taken down by a burst of radiation. They may mean that using radiation hardened parts will be necessary for computers on future flights, which will be more expensive and will slow down processing.
 
Smith also notes that one of the Draco thrusters, which help the Dragon to maneuver, failed and that all three coolant pumps failed after the Dragon splashed down. Also the freezer unit used to return experiment samples from the ISS was at minus-65 degrees than at the required minus-95 degrees. What the 30-degree difference has done to the samples if anything has yet to be determined.
 
NASA and SpaceX reviewing the anomalies

According to Space Flight Now, NASA officials discussed the various anomalies on Nov. 14. Thus far the root cause of the engine failure has not been found. Engineers suspect that sea water may have leaked into the Dragon, causing the freezer and the coolant pumps to lose power. Cold stowage may be limited on subsequent flights of the Dragon.
 
Partly due to the problems being worked on the Dragon and partly due to a software upgrade on the International Space Station, the next cargo flight has been delayed from January 2013 to March. NASA, as the customer, must sign off before a Dragon embarks on another mission to the ISS.
 

http://news.yahoo.com/nasa-spacex-fix-anomalies-last-dragon-cargo-flight-202900372.html

[Unorthodox]

The engine outage was relatively "normal".  Welcome to liquid engines. 

I'm baffled the computers weren't radiation hardened in the first place, but again, there's a reason for the redundancies. 

Hadn't heard of the freezer thing before.