Space Adventures
I am going to order it.
Here is some personal space history with some Capcom/Astronaut communication that you may find interesting Ref. SRTM and STS-99:
... The launch was flawless. Everything depended on the upcoming deployment of the mast.
At 17:25 the latches were open and the “milk stool” (the three legged motorized structure used for precise alignment of the Outboard Antenna after mast deployment) was clear of the end of the canister. The defining moment was at hand. At 17:28 the mid-deck video was trained on the end of the canister where the mast was supposed to emerge from its collapsed stack of short lengths of longerons, battens, cables and latches to form this incredibly stiff 60 meter structure extending the outboard antenna into perfect orientation for the mission. Out it came without hesitation, absolutely beautiful.
For several days the mast performed well but now it would have to retract and stow. Many months before, I had witnessed the –60 degree C, low temperature retraction tests at AEC Able in Goleta, California.
In the test, the mast retracted properly to within less than an inch of full stow and it would go no further. It seemed if we had a little more power we could overcome the resistance and drive it home. The motor manufacturer reluctantly authorized a higher power setting for a very limited time to be followed by no power application for a long recovery period. This was applied and a very slight movement was seen in the closure direction followed by a return toward the original position when the power was removed. The mast did not completely retract and stow. It was decided that we should try backing it out a little and try it again with the higher power and some momentum. After a short extension there was a catastrophic failure of the mast with the attendant fracture noise and the sound of many hard metal balls striking the wall of the canister like marbles in a barrel.
After a long study it was determined that when the mast was prevented from full retraction it was impossible to assure that all four corners of the mast at a given frame were properly latched. When we reversed direction one corner was latched and the adjacent one was not. The batten in the frame between these two corners was placed under tremendous tension as one corner moved out and the other was held back. The batten was pulled apart and the corner rollers were shattered dumpling the ball bearing components in the canister. From this knowledge came the flight rule that the mast would not be reversed to the deploy direction unless it was fully retracted and latched.
We determined by testing that there was an extreme increase in the wire insulation’s resistance to change when the temperature fell from –45 down to -60 C. The damaged section of the mast was rebuilt and the special ball bearing “plastic” rollers at the corners of the outer eight bays were replaced with solid bronze rollers. The retraction test was repeated at –45 C and the retraction and stow were successful. At –60 C it failed. A new test where the mast would be extended out just a couple of bays, cold soaked at –60 degrees C and then retracted was run. It worked perfectly. Thus it was concluded that the problem was caused by trying to compress wires back into the stowage space at the bottom of the canister after they had been stretched out 200 feet and frozen to –60 C. Heaters were added to the inner walls of the canister to warm the wire insulation as it retracted and the emergency mast retraction power option was also added to the design. It was determined that the mast would never see anything near –45 C let alone -60 and if we had a problem the Shuttle could be rolled to a position where the sun could be used to warm up the mast. With the design and operating procedure changes driven out by the environmental test failures SRTM was as ready for the mission as we could make it.
The following are my notes from that early morning on February 21, 2000:
- The monitor is on channel 39 and they are currently showing the deployed mast. It is shining so bright in the sun light that it is hard to make out detail.
- 0:3:40 they cut back on the brightness or the Shuttle is going into night sky because you can now barely see the mast.
- 03:49 they just announced one more data take to go and they are now over the Australian Continent. PHRR1 Removed tape C209, inserted tapeC211; PHRR2 remove tape C210, inserted tape C212.
- 03:55 mapping complete, AODA safe.
- Announcement - end of mapping.
- 03:57 Canister heater is on according to the announcer (Houston Mission Control)
- 04:05 Good picture of the mast and one of the astronauts (woman) announced, “Beginning mast stow.”
- 04:06 they just inserted a good view of the mast section near the canister. I wouldn’t be surprised if Howard Eisen asked for that.
- 04:08 now they are zooming in on the outboard antenna. It has to flip to its stow position before the retract.
- 04:23 Astronaut announced, “Go for flip” [of the outboard antenna]. Capcom said standby 5 minutes.
- “Go for Foxtrot 1” 04:24 (Capcom).
- 04:25 Flip of the outboard antenna has begun. Looks very good.
- 04:33 the flip appears complete but I’ve heard nothing.
- 04:33 Astronaut (man) said, “Go on Gulf.”
- Capcom said “Roger standby.” I’m sure the flip is complete and they are verifying that everything is OK.
- 04:41 there must be some concern or I think they would have started to retract the mast by now.
- 04:41 “Go for Gulf.” From Capcom so I guess everything is OK.
- 04:43 Go step I, hold step J.
- 04:45 Step I complete, requested hi-definition TV of retraction. Capcom said, “Copy step I complete and we’ll let you know.”
- 05:02 Houston Mission Control said it will be 17 more minutes before the start of mast retraction.
- Capcom gave OK to retract at the scheduled time. That should be 2 minutes from now.
- 05:20 there it goes, looking good, steady and smooth.
- 05:20 20 bays retracted according to Houston Mission Control. It appears to be going slower to me.
- 30 bays in at 05:27.
- 40 bays in 05:29
- 50 bays in 05:31
- 60 bays in 05:33
- I saw the seven striped batten about one bay from the canister at 05:34
- 05:35 picture back.
- 05:38 stopped motion.
- 05:39 Evaluating indication. Power off called for and complied with.
- There appears to be an anomaly. 05:44
- 05:45 HMC just said they have no indication of latch.
- It appeared to me that the cover did not close all the way.
- 06:23 still no answer. Capcom just told the astronauts that they are still studying the problem and will get back to them as soon as they can.
- 06:34 Houston called with a plan.
1- Page 1-18 seg D step 2 through 9 (unintelligible note)
2- Page 3-9 step 5-11 seg J run 30 seconds
3- Page 3-10 step K to turn mast power off if motion seen
4- Page 1-19 seg E steps 1-15 if no motion call MCC.
- They hope the heat has softened the cables so the stow can be completed.
- Power on 06:44:45. Some small movement seen at start-up then nothing but high currents were observed. This is exactly what we saw in the –60 degree C retraction test at AEC Able. No good.
- Now they are working on a new plan “B” – heaters to the limit.
- They are going to repeat the max torque.
- Astronauts suggested backing up slightly then go in.
- Houston Capcom said this was discussed and they want to focus on inward direction only for now. I’m sure this is because of our catastrophic failure of the mast when we tried this at AEC Able during the –60 degree C test.
- Power on 07:08:17. Had some movement in, then stall and back to half of the original closure distance when power was removed.
- Thinking again now.
- 07:43 new plan. Same as old max torque but three times, 15 seconds each time and 5 minute wait between.
- 07:50:37 the stow was effective on the first try!
Bob Axsom