A detailed review of SLS’s present launch status
Link here. The article provides a detailed look at the engine controllers in the former shuttle engines that SLS is using on its core first stage, including some details about the failed unit and the issues involved in replacing it.
I found this historical data in the article most interesting:
The first attempt to launch Orbiter Atlantis and the STS-43 Shuttle vehicle was scrubbed before dawn on July 24, 1991, when the primary computer, DCU A, failed while propellants were being used loaded into the External Tank. … As a result, the launch was scrubbed to allow replacement of the controller, and the launch was rescheduled for August 1, 1991. The failure analysis of the controller revealed a broken blind lap solder joint connection of the bit jumper to the half stack, which is not a generic design problem.”
According to contemporaneous Shuttle Status Reports issued by NASA Public Affairs at KSC in late July, 1991, after the launch was scrubbed and the External Tank was drained and inerted, access to the engine area for maintenance was established on July 26. The broken engine controller was removed, and a new one was installed on July 27, followed by testing to verify the new controller on July 28; the three-day countdown was started over from the top on July 29 for the next launch attempt on the morning of August 1.
It took NASA less than a week to replace an engine controller in 1991. Now, it appears it might take NASA several months, including testing, to do the same thing on SLS. Moreover, the article suggests that there are other subcontractors and organizations (such as the range safety) that are also having trouble being ready for the presently scheduled mid-February launch.
All in all, this report suggests that SLS will not launch in February, will be delayed until April, with a strong chance that even that April date might not be met.
The report also illustrates the sluggish manner in which NASA operates today. Nothing is done with any speed. No task is done in one day if it can take a week. This is bad management, and also a very dangerous way to operate, as it actually encourages sloppiness because no one is under any pressure to work hard. The result has been endless niggling failures, each of which delays things interminably.
Link here. The article provides a detailed look at the engine controllers in the former shuttle engines that SLS is using on its core first stage, including some details about the failed unit and the issues involved in replacing it.
I found this historical data in the article most interesting:
The first attempt to launch Orbiter Atlantis and the STS-43 Shuttle vehicle was scrubbed before dawn on July 24, 1991, when the primary computer, DCU A, failed while propellants were being used loaded into the External Tank. … As a result, the launch was scrubbed to allow replacement of the controller, and the launch was rescheduled for August 1, 1991. The failure analysis of the controller revealed a broken blind lap solder joint connection of the bit jumper to the half stack, which is not a generic design problem.”
According to contemporaneous Shuttle Status Reports issued by NASA Public Affairs at KSC in late July, 1991, after the launch was scrubbed and the External Tank was drained and inerted, access to the engine area for maintenance was established on July 26. The broken engine controller was removed, and a new one was installed on July 27, followed by testing to verify the new controller on July 28; the three-day countdown was started over from the top on July 29 for the next launch attempt on the morning of August 1.
It took NASA less than a week to replace an engine controller in 1991. Now, it appears it might take NASA several months, including testing, to do the same thing on SLS. Moreover, the article suggests that there are other subcontractors and organizations (such as the range safety) that are also having trouble being ready for the presently scheduled mid-February launch.
All in all, this report suggests that SLS will not launch in February, will be delayed until April, with a strong chance that even that April date might not be met.
The report also illustrates the sluggish manner in which NASA operates today. Nothing is done with any speed. No task is done in one day if it can take a week. This is bad management, and also a very dangerous way to operate, as it actually encourages sloppiness because no one is under any pressure to work hard. The result has been endless niggling failures, each of which delays things interminably.