I'll write it up, but we have documentation from this week (L2) referencing 135 and the decision timeline (late Spring).
When will we know for sure whether STS-135 will fly or STS-133 will be the last shuttle flight? When will NASA officially announce ?
To add (well, maybe...) to Chris's answer, it's going to be dependent on factors that are still variable. IMO, one of those is how much money Shuttle Operations is given in the budget for FY 2011; we'll see what the administration proposes next week.
Upmass, and no close LON since RTF. I'd go for this.
The efforts required may just be higher than the benefits if you look at it from a STS program management perspective.
Right, and this is why the possibility is losing favor even if the funding for the flight would mostly be there.
What is your source for this (losing favor)?
Not always people want to appear on NSF (or elsewhere, for what matters) with full name and details, but, you can check the "unconfirmed rumors" with your own sources. Sure I'm not going to burn mine.
STS-135 is not dead, as other people claim in the budget threads. If the manifest proceeds smoothly and there are no large delays, it still has good chances of flying. NASA already has successfully added to the manifest the two "contingency" logistic missions. (I won't get into the AMS-2 because that's a whole different story, there was huge lobbying, and, it should have been common sense.) It is quite possible that STS-135, which is mostly funded anyway (as a LON), will be sold, in the view of the ISS extension likely to be beyond 2020, and in front of a reliance upon Soyuz vehicle which is anyway going to be a fact after the last Shuttle flight. While the NASA incapability of telling the public and the politicians how much it costs to fly a space shuttle mission, after flying quite a few of those (that's what happened with STS-134 basically) is unpleasant and annoying, as long as the manifest holds and everything goes smoothly as it has been going for some time, STS-135 still has good chances. It's not a done deal, though, not by any means.
Other extensions are by now quite dead.
What is your source for this (losing favor)?
Not always people want to appear on NSF (or elsewhere, for what matters) with full name and details, but, you can check the "unconfirmed rumors" with your own sources. Sure I'm not going to burn mine.
STS-135 is not dead, as other people claim in the budget threads. If the manifest proceeds smoothly and there are no large delays, it still has good chances of flying.
Which contradicts the assertion it was losing favor. It's up in the air or TBD, but that's not the same thing, either.
I disagree. We "need to" if we want to use all the assets (ET-122) we have. You are planning for multiple failures occuring at once. Which is costly, and therefore seldom done.
It being done here is the reason why many worthy things are not done, including one single flight without LON after more than 100 of these were flown in over two decades. The last percentage digit of safety always is the most expensive. This is were risk aversion turns into waste. Same for CxP Orion/Ares I.
Analyst
I disagree with the notion we can just fly one single last flight without LON. NASA has decided to implement the LON requirement for good reason and shouldn't abandon it without good reason. Bringing some upmass to the ISS with STS-135 isn't a good reason enough.
The LON was implemented because of emotion after the Columbia tragedy, one may argue that when it did make sense to consider a LON (precisely the Columbia) no action was taken and the crew was not even informed, but the damage was downplayed also to them. In any case, after Columbia, if there had been non-repairable damage to reentry systems, a LON would have flown, if technically possible. (And then the program would likely have been terminated). At this point, it is far from obvious that a LON would be flown. Likely the program would end there, the Orbiter would be jettisoned or perhaps an unmanned landing attempted, the LON would stand by while alternatives are explored and carried out.
Really the LON requirement does not have a lot of ground. If a vehicle is not safe enough to rely upon itself, you send up two of them, simultaneously, in an emergency, and while one of them is in avaria? (And to top it off - when you never, ever, sent up two simultaneously under normal operations?) If a vehicle is not safe enough to rely upon itself, one can improve safety, can abandon the vehicle, can live with the risk, but, a LON is not really useful to improve the chances, except in very unlikely situations.
Which contradicts the assertion it was losing favor. It's up in the air or TBD, but that's not the same thing, either.
psloss I am not a native english speaker and so may be I explained myself badly (sorry about that), what I meant to say is that a number of weeks ago its chances to fly looked a little bit better than they are now, and that the reason is exclusively political / management, not any technical reason.
Really the LON requirement does not have a lot of ground. If a vehicle is not safe enough to rely upon itself, you send up two of them, simultaneously, in an emergency, and while one of them is in avaria? (And to top it off - when you never, ever, sent up two simultaneously under normal operations?) If a vehicle is not safe enough to rely upon itself, one can improve safety, can abandon the vehicle, can live with the risk, but, a LON is not really useful to improve the chances, except in very unlikely situations.
I have to disagree with this. LON is not the only precautionary measure that was implemented after the loss of Columbia. Many others mitigate the risks that the orbiters will encounter during launch, orbit and landing. That said, the chances that an LON would be needed are already VERY slim. It's there for that just-in-case scenario that you hope never happens. Think about it - If the chances of just ONE orbiter encountering problems requiring LON are so slim, think of how slim the chances that TWO orbiters would encounter that sort of damage in two consecutive flights. They're slim to just above none.
Also, it has nothing to do with a vehicle not being able to rely on itself or not. It has everything to do with risk of debris encountered by that vehicle. Foam from the ET is not the only risk factor here. You have to consider MMOD. The foam issue has been dealt with for the most part and we have not seen significant damage since STS-107. That says that the vehicle can be much safer than they ever aspired to make it before. Now it burrows down to risk. It's much lower than it was before Columbia, and if a rescue mission was never needed in 111 successful flights beforehand in an era that was much more dangerous than the one we live in today, it probably won't be needed in the era in which the shuttle is at its safest. But it's there, just in case.
Sure, many other measures have been taken, I have not directed my comment towards them, in fact the safety of the system has been, under many aspects, vastly improved since RTF2. What I said is that LON was an option for Columbia and was not considered, or at least, not openly considered, which was emphasized heavily by the commission and of course led to the decision of implementing it as an option on each flight; and that the chances of encountering other situations that could take benefit from a LON are extremely slim.
If an orbiter is safely docked at ISS (current orbit, or lower orbit) but can not safely land, there are not many possible failures for that scenario. There is the TPS, which can be damaged by foam and debris from the ET, from the boosters (rarer than the ET events but it happened), from other random junk (micrometeoroids, space junk, and the like).
Whatever process proves to fail in hypotetical stack "X" is going to be a process which has been implemented in stack "X+1", the probabilities are not independent.
Sure, even a faulty process usually performs alright in most of the cases, but failure for a LON is catastrophic; what you do if you have four more astronauts stranded on the ISS, and worse, they are all alive, and the president of the USA, on the phone with the president of Russia and other international partners, has to decide who is going to live and who is left to a very uncertain destiny, to use an euphemism? and this in cold blood, not like it happened with the tragedies that happened with the program. Can you imagine the press, the TV?
This would have an effect well beyond a tragedy like LOCV (which is tremendous already) this would likely mean the end of human spaceflight in the USA for many decades, 80-100 years, you understand it's very hard for anyone to take that risk. Not the end of USA human launch vehicles, the end of american HSF period. (I don't know what the decision-makers for Columbia were thinking, but who can exclude that they did consider it and rejected it on these grounds? I believe they were wrong, but it is an uncomfortable position, no question about that.)
The micrometeoroids or space junk are really not that different, if we fail to monitor them at time of orbiter "X", we will hardly feel confident we will monitor them properly when it comes to the LON a few weeks later. (Small TPS damage can and will be repaired by the crew.)
Then there is OMS that could have critical failures, this system is very redundant, should both of them fail simultaneously would you feel confident about sending a similar vehicle up there? regardless of how low is the probability, orbiters are prepared in the same way, and pass through the same flight readiness tests, which, should such an event occur, obviously it'd show they are inadequate - which can not be fixed in a few weeks, no way.
Same for critical power failures and the like. Probabilities are far from independent, that's why LON helps only in very unlikely situations.
Sure, even a faulty process usually performs alright in most of the cases, but failure for a LON is catastrophic; what you do if you have four more astronauts stranded on the ISS, and worse, they are all alive, and the president of the USA, on the phone with the president of Russia and other international partners, has to decide who is going to live and who is left to a very uncertain destiny, to use an euphemism? and this in cold blood, not like it happened with the tragedies that happened with the program. Can you imagine the press, the TV?
This would have an effect well beyond a tragedy like LOCV (which is tremendous already) this would likely mean the end of human spaceflight in the USA for many decades, 80-100 years, you understand it's very hard for anyone to take that risk. Not the end of USA human launch vehicles, the end of american HSF period.
What makes you think they'd fly STS-135 without ample Soyuz rescue capability? They wouldn't - so your fear is null and void.
I totally agree that STS-135 if it flies will fly with a rescue capability like all other flights with a LON in place. And if it does not fly, it won't be for safety considerations, as its safety as far as we can model is no different from sts-130 all the way to sts-133. I am sorry that English is not my native language so may be some things don't come across as I mean them.
I was in fact pointing out that with all other missions that have been flying and will fly with a LON in place, the likelyhood of the LON being actually useful / being actually launched, was low, and it's now even lower than that. LON has been considered in internal documents for a long time well before being officially implemented, still, even for Columbia it was not carried out.
Now that president Obama has released NASA funding details, can any one comment about the future of STS-135 with some certainity ? (space station life is to be extended till 2020) Hence how will that affect a STS-135 decision? provided that an additional flight could carry much needed spares to the station.
Now that president Obama has released NASA funding details, can any one comment about the future of STS-135 with some certainity ? (space station life is to be extended till 2020) Hence how will that affect a STS-135 decision? provided that an additional flight could carry much needed spares to the station.
No change. Decision in April, as it was before. A smooth move through the scheduled five will help, but there wasn't any negative impact from today.
I'll include what we have on L2 (last week memo and today (coincidence) crew loading memo) in an upcoming article.
Now ceased "unless a compelling need arises" - per L2 DA Notes.
Thanks Chris for letting us know. It is sad that there wont be a STS-135 mission unless some thing comes up.
Now ceased "unless a compelling need arises" - per L2 DA Notes.
So most likely no STS-135?
Now ceased "unless a compelling need arises" - per L2 DA Notes.
So most likely no STS-135?
Correct, unless a major issue that NEEDS the Shuttle arises, and I hope nobody here is hoping for one.. because that probably wouldn't be a good "issue".
STS-135 cull roundup:
http://www.nasaspaceflight.com/2010/02/progress-m-04m-launches-to-cost-cutting-iss-sts-135-addition-removed/
Good article. This is the key quote in there in my opinion: "“For now, adding the LON as actual flight will end unless a compelling need arises.” A compelling reason is a cargo upmass shortage of any kind. That compelling reason may just come sooner than NASA is thinking which puts them back on baselining the mission again. I hope Falcon 9 succeeds in its test flight, but it might fail and put a potential additional one year delay to the first CRS flight into the ISS program.
For now I don't really understand NASA's decision. The much more prudent way of moving on would be to baseline STS-135 as both a LON and a "compelling reason" aka upmass shortfall / required spares flight. Well, maybe there are too many troubles to work out with the Russians regarding a Soyuz rescue.