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#160
by
dsmillman
on 15 Apr, 2011 16:29
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I believe that limiting the crew size to 4 was due to the lack of a Shuttle rescue mission for STS-135. I understand it could take the better part of a year to have Soyuz spacecraft bring down the STS-135 crew.
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#161
by
Lee Jay
on 15 Apr, 2011 16:30
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I believe that limiting the crew size to 4 was due to the lack of a Shuttle rescue mission for STS-135. I understand it could take the better part of a year to have Soyuz spacecraft bring down the STS-135 crew.
I forgot about that. That's why I asked.
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#162
by
Space101
on 15 Apr, 2011 16:33
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Two massive missions. And they say retirement wasn't a mistake?
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#163
by
Space Pete
on 15 Apr, 2011 17:23
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The RSP is now loaded with cargo.
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#164
by
steveS
on 16 Apr, 2011 03:50
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Chris G;
On your latest article about the tight STS-135 timeline;
Currently, 12 day flight means, 11 days 19 hours? (assuming Atlantis lands with no delays). You have mentioned descending node entry will buy 28 hours of extra timeline. So does it mean that 11 days, 19 hours + 28 hours or 11 days, 19 hours remain the same but 28 hours can be added for docked time at ISS?
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#165
by
Space Pete
on 16 Apr, 2011 15:25
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3 hours on a Friday afternoon to catch up with paperwork....feels like someone gave me $50. Big move to add Soyuz fly-about to 135.
A "big move"? Sounds promising!
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#166
by
ChrisGebhardt
on 16 Apr, 2011 15:46
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Chris G;
On your latest article about the tight STS-135 timeline;
Currently, 12 day flight means, 11 days 19 hours? (assuming Atlantis lands with no delays). You have mentioned descending node entry will buy 28 hours of extra timeline. So does it mean that 11 days, 19 hours + 28 hours or 11 days, 19 hours remain the same but 28 hours can be added for docked time at ISS?
11days 19hrs + 6hrs, actually. Complicated explanation, but the descending node entry buys 6hrs of orbital time. The additional time (to get us to ~28hrs) comes from the just over 1hr of additional USABLE crew time from each of the four crew members over the life of the mission from sleep shifting forward a total of 2hrs.
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#167
by
Space Pete
on 16 Apr, 2011 15:49
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So, I was thinking some more about how the EVA could potentially be dropped from 135.
The EVA objectives (in priority order) are PM transfer from ESP-2 to LMC, RRM transfer from LMC to SPDM, MISSE-8 setup, and CP7 ETVCG R&R.
Let's assume the MISSE-8 setup and CP7 ETVCG R&R are dropped, since they are not "mission essential" items (i.e. they can be done another time).
Now, seems as the PM transfer from ESP-2 to LMC would need to be done first, how about ground controllers remove the PM from ESP-2 prior to 135, using the SPDM? Then, as soon as Atlantis docks and the MPLM is installed, ground control could get to work with the SPDM, installing the PM onto the top of the LMC, and removing RRM from the bottom. In total, those operations shouldn't take more than a day, and would have zero impact on crew time. We already know that the SPDM can successfully complete FRAM ops, since we saw that with HTV-2.
This plan might require the MPLM to be placed on Node 2 Zenith in order to create PLB access for the SSRMS/SPDM, but that shouldn't be a showstopper.
Thoughts?
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#168
by
Orbiter
on 16 Apr, 2011 15:51
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I could see the EVA being dropped from 135's timeline in that case Pete.
Orbiter
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#169
by
steveS
on 17 Apr, 2011 01:05
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11days 19hrs + 6hrs, actually. Complicated explanation, but the descending node entry buys 6hrs of orbital time. The additional time (to get us to ~28hrs) comes from the just over 1hr of additional USABLE crew time from each of the four crew members over the life of the mission from sleep shifting forward a total of 2hrs.
Thank you very much for the explanation Chris. What I thought earlier was, no matter what (ascending/descending entry), each astronaut will have a FIXED rest/sleeping time during a day. Can you briefly explain why depending on ascending/descending entry, the crew resting period changes for STS-135?
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#170
by
Lee Jay
on 17 Apr, 2011 02:19
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11days 19hrs + 6hrs, actually. Complicated explanation, but the descending node entry buys 6hrs of orbital time. The additional time (to get us to ~28hrs) comes from the just over 1hr of additional USABLE crew time from each of the four crew members over the life of the mission from sleep shifting forward a total of 2hrs.
Thank you very much for the explanation Chris. What I thought earlier was, no matter what (ascending/descending entry), each astronaut will have a FIXED rest/sleeping time during a day. Can you briefly explain why depending on ascending/descending entry, the crew resting period changes for STS-135?
Since no one has answered, I'll give it a try in hopes someone will correct me if I say something wrong.
Start with the fact that the entry day has a pretty fixed timeline, which means you have to start at a particular time for that particular entry.
Next, realize that the ascending and descending nodes are around 12 hours apart. So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
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#171
by
bholt
on 17 Apr, 2011 02:54
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
Maybe Discovery should have been turned around for this flight. (Although that would have slipped the late June launch, I suppose)
I know I am probably being overly simplistic.........
Brent
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#172
by
Sesquipedalian
on 17 Apr, 2011 03:11
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#173
by
robertross
on 17 Apr, 2011 03:21
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
Maybe Discovery should have been turned around for this flight. (Although that would have slipped the late June launch, I suppose)
I know I am probably being overly simplistic.........
Brent
The underlying problem was the required Orbiter Maintenance Down Period, where they had to go into all the hard-to-reach areas & inspect the orbiter. Discovery's time was up, Endeavour is flying, which leaves Atlantis. That's how the cards fall. Delaying the program is obviously not an option - and we're just lucky to get this flight.
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#174
by
psloss
on 17 Apr, 2011 11:26
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Next, realize that the ascending and descending nodes are around 12 hours apart. So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
The principle is correct, but ascending and descending nodes are ~6 hours apart.
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#175
by
psloss
on 17 Apr, 2011 11:47
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
The underlying problem was the required Orbiter Maintenance Down Period, where they had to go into all the hard-to-reach areas & inspect the orbiter.
Time and cycle issues for the other orbiters might be one factor, but the bigger one was resources / money. With the workforce being reduced every quarter, there are no longer enough resources to turn around either of the other two vehicles fast enough after their flights to "go again." (Probably the case for some months now.)
The SSPTS question is an interesting one, but one of the issues was probably circumstance -- a lot of the time between Atlantis's flight after the last HST servicing mission and her next one was eaten up by the last big delay before launch.
That's how the cards fall. Delaying the program is obviously not an option - and we're just lucky to get this flight.
Yes, unfortunately.
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#176
by
ChrisGebhardt
on 17 Apr, 2011 21:24
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
Maybe Discovery should have been turned around for this flight. (Although that would have slipped the late June launch, I suppose)
I know I am probably being overly simplistic.........
Brent
The underlying problem was the required Orbiter Maintenance Down Period, where they had to go into all the hard-to-reach areas & inspect the orbiter. Discovery's time was up, Endeavour is flying, which leaves Atlantis. That's how the cards fall. Delaying the program is obviously not an option - and we're just lucky to get this flight.
Close, but Discovery's OMDP timeline was extended out through STS-133 and Jan. 2012. As Philip says above, though, money was the bigger factor here. They didn't want to spend all that money installing SSPTS on Atlantis for only two flights (129 and 132). Remember, 135 was not on the radar at that time.
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#177
by
ChrisGebhardt
on 17 Apr, 2011 21:35
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
Maybe Discovery should have been turned around for this flight. (Although that would have slipped the late June launch, I suppose)
I know I am probably being overly simplistic.........
Brent
Not a mistake at all. Remember, STS-133 was originally an 8+1+2 day mission with 0 EVAs. It was subsequently modified over the course of several months to an 11+1+2 mission with 2 EVAs before finally landing pre-launch at 12+1+2 days. (Any orbiter could have flown this mission based on it's original requirements.)
STS-134 was originally a 12+1+2 day 3 EVA mission. It was subsequently extended to a 14+1+2 day 4 EVA mission and then, just last week, to 14+2+2 mission. (Again, any orbiter could have flown this mission based on it's original requirements.)
STS-135 was originally the STS-335 crew rescue mission for STS-134. Atlantis was next up in the rotation. Decisions and meeting went back and forth between an 11+1+2 day 0 EVA mission and a 12+0+2 day 1 Station-crewed EVA mission. Eventually, they settled on 12+0+2 days. (Again, any orbiter could have been assigned this mission based on its ORIGINAL requirements.)
Further, as outlined in the article on site right now, the timeline issues are not insurmountable -- just highlighted more than usual because Atlantis can only launch into at 12+0+2 day maximum mission.
Lastly, remember that before the Station was equipment with enough solar arrays, the Shuttles could NOT draw power from it. STS-118 was the first mission to use SSPTS -- and that was in a test situation. STS-120 was the first mission to really utilize SSPTS. Further, Discovery has launched into non-/minimal SSPTS missions since then. STS-128 and STS-133 spring to mind immediately.
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#178
by
robertross
on 17 Apr, 2011 22:16
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Was it a mistake to choose Atlantis for this mission? (Or should they have installed a SSPTS?)
Maybe Discovery should have been turned around for this flight. (Although that would have slipped the late June launch, I suppose)
I know I am probably being overly simplistic.........
Brent
The underlying problem was the required Orbiter Maintenance Down Period, where they had to go into all the hard-to-reach areas & inspect the orbiter. Discovery's time was up, Endeavour is flying, which leaves Atlantis. That's how the cards fall. Delaying the program is obviously not an option - and we're just lucky to get this flight.
Close, but Discovery's OMDP timeline was extended out through STS-133 and Jan. 2012. As Philip says above, though, money was the bigger factor here. They didn't want to spend all that money installing SSPTS on Atlantis for only two flights (129 and 132). Remember, 135 was not on the radar at that time.
But Discovery had to have a CR for an extension for flight STS-133 to make it its 9th flight, not just 2012 (they were only allowed 8 flights or 5.5 years). So it's time was up, regardless.
(based on this L2 document
http://forum.nasaspaceflight.com/index.php?topic=20574.0)
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#179
by
Space Pete
on 18 Apr, 2011 14:04
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Another RSP is getting ready to go into the MPLM.
