Last week I was surprised to see a ring shape structure with solar panels detach from the Ares V's Earth departure stage just before trans-lunar injection, while relaxing watching another Constellation architecture video at the AIAA/ESA/Eumetsat Space Operations 2008 conference in the beautiful Heidelberg
So surprised I fired off an email to the helpful PR folks at NASA Marshall Space Flight Center asking if the skirt was a recent change and this was the reply from Ares projects manager Steve Cook - see extended entry
"This is not a recent change. We have had a loiter skirt concept since the earliest Earth departure stage (EDS) studies. It is jettisonable structural ring on the aft end of the EDS which is mounted to the dedicated power and thermal control systems required to maintain the EDS in LEO prior to the trans-lunar injection burn. The loiter skirt is shed before trans-lunar injection to avoid carrying extra mass to the moon."
I have had a good look through the Youtube hosted Constellation videos and couldn't find the video we were shown by NASA's Greg Chavers and tried to google EDS images to see if the loiter skirt with its identifable blue solar panels could be seen in any of them, but no luck
Now it is true that Aviation Week's Frank Morring mentioned the skirt in passing in this article but I don't remember NASA's exploration launch project office's advanced planning manager and former Apollo programme rocket engineer Phil Sumrall (Frank and I did the interview with Phil at the same time at the 3rd space exploration conference) mentioning that it was expendable and I didn't mention it all in my article or my blog post and I can't find any mention of this skirt anywhere in the English language media before February - care of Lexis Nexis
As for speculating why such a feature of the EDS should suddenly appear in videos now, it is true that solar panels were needed by the EDS when it had its 90-day plus low Earth orbit loiter before docking with the Orion crew exploration vehicle but Sumrall told us that at a 4-day or less loiter batteries could be sufficient
Or have they realised that solar panels on a skirt could be used for one to four days and then detached to reduce EDS mass and improve its delta-v capability? They do have an issue with Altair's ability to get the Lunar Architecture Team's preferred cargo mass to the lunar surface; 2,000kg with crew as opposed to LAT's 6,000kg with crew target
Anyway, my search for the video I saw did turn this up; another Constellation video that I had'nt seen but not the one from Heidelberg. I can't remember if this was shown at the 3rd space exploration conference in Denver in February or not