EFT-1 launch scrubbed due to valve issue
The long-anticipated Exploration Flight Test 1 (EFT-1 ) for the Orion Multi-Purpose Crew Vehicle, which was slated to launch at 7:05 a.m. EST (1205 GMT) on Dec. 4, was scrubbed near the end of the launch window after several aborted attempts.
Initially the weather was favorable and all looked well for the sunrise launch. However, due to a boat in the restricted area, the launch was delayed during the built-in hold until the boat was moved. Though the boat was cleared relatively quickly, there was also an issue with second stage propellant conditioning.
With these issues, the launch was delayed until 7:17 a.m. EST. That launch attempt made it to the terminal count, yet with approximately three minutes remaining a hold was called due to a ground wind violation.
The next attempt was set for 7:55 a.m. EST, and again, during the terminal count the attempt was aborted due to ground wind violation. High-speed wind gusts can trigger the automated alarm and cause a launch to be held in the last moments.
One more attempt was set for 8:26 a.m. EST, and it too was aborted during the terminal count. This time the cause was an issue with the fuel drain valves on the Common Booster Cores. According to Dan Collins of United Launch Alliance (ULA ), the hydrogen valves “had gotten cold and a little sluggish in their performance” based on the last time a similar issue arose. At the time of the NASA press conference on the scrub, the data had not yet been fully assessed to definitely determine the root cause.
A final launch attempt for the day was declared for 9:44 a.m., the end of the two-hour-and-39-minute launch window. Troubleshooting on the valves was attempted, and NASA officials had the automated wind alarm disabled to avoid more delays due to wind gusts, but in the end a scrub was called.
The next attempt for launch of EFT-1 is currently planned for Friday, Dec. 5, at 7:05 a.m. EST (1205 GMT), though this could change. The weather forecast is somewhat less favorable for that time. Collins stated in the NASA press briefing that a Delta IV Heavy can attempt a launch two out of three consecutive days, as it will then need to have the ground tanks refilled.
If attempts are made on Friday and another scrub is called, they will have to stand down on Saturday and schedule the launch for a different day. If it is not safe to proceed on Friday, they will wait until Saturday for the next attempt. For its part, NASA lauded the efforts to get Orion into the clear blue skies, with NASA commentator Michael Curie referring to them as: “Valiant.”
Rae Botsford End is a freelance writer and editor whose primary work currently is writing technical white papers, contributing to SFI, and working on a speculative fiction novel that she hopes to have published soon. Rae wanted an opportunity to report on the various space-related events in and around Florida's Space Coast and approached SFI's founder about the possibility. Rae now covers an array of subjects for our growing website.