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Off-Topic Discussion => General Discussion => Topic started by: Nuclear1 on February 26, 2011, 05:27:33 pm

Title: Discovery, on final mission, docks with ISS
Post by: Nuclear1 on February 26, 2011, 05:27:33 pm
http://www.bbc.co.uk/news/science-environment-12589183?utm_source=twitterfeed&utm_medium=twitter
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The US space shuttle Discovery has docked at the International Space Station.

It has docked for the last time, as it is set to be retired after this mission and placed in a museum.

This is the 13th time it has flown to the space station, where it is to deliver a new store room and a sophisticated humanoid robot.

Only two further flights remain by Endeavour and Atlantis, which Nasa wants concluded in the coming months.

Discovery set off on its 11-day mission from the Kennedy Space Center on Thursday.

Only two more left guys...
Title: Re: Discovery, on final mission, docks with ISS
Post by: watsisname on February 26, 2011, 05:30:12 pm
It's sad the shuttle program's almost over. :(  I'm hoping to drive down to the Cape and watch one of the last two launches.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 26, 2011, 10:08:36 pm
End of an era.  :( Last time I was down there a bunch of the (unhappy) Cape staff said the orbiters were basically in factory condition. Just no money to keep them flying.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Kosh on February 26, 2011, 11:24:18 pm
The shuttles should have started being phased out 20 years ago. About time these dinosaurs went extinct.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuclear1 on February 26, 2011, 11:44:40 pm
The shuttles should have started being phased out 20 years ago. About time these dinosaurs went extinct.
Well...with the MIC sucking away all of NASA's funding, they have to make do with what they have, which isn't much.

And they've done a wonderful job with what they have.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 26, 2011, 11:48:18 pm
The shuttles are amazing, great pieces of engineering. Whether they're economical is a moot point, we have nothing better and no will has ever existed to try.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Kosh on February 27, 2011, 12:08:49 am
The shuttles are amazing, great pieces of engineering. Whether they're economical is a moot point, we have nothing better and no will has ever existed to try.

No, they most certainly were not great pieces of engineering. Thanks to meddling by the Air Force, the designs were overly complicated and needed huge support staffs to maintain properly. Classic design by committee.

The fact that we have nothing better has quite a bit more to do with NASA's bureacratic inepitutude than any percieved advanced engineering.

http://www.idlewords.com/2005/08/a_rocket_to_nowhere.htm
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 12:19:23 am
The shuttles were fantastic pieces of engineering. There's simply no disputing it. No orbiter has ever suffered a significant failure. Arguing that the design was compromised from the beginning is tangential; they performed beautifully in a role never before attempted by mankind.

Could they have been designed better? Also indisputably - nothing in that link is new to anyone paying attention - but it hardly matters. Everything can be improved, of course, but no improvement has been made because no will has existed to do so. There could be a thousand things that might have been done better, but they will all pale beside the achievement the orbiter represents.

The shuttle remains a monument to engineering excellence, simply because it is so complex and yet performs so well. Its retirement is the end of an era.
Title: Re: Discovery, on final mission, docks with ISS
Post by: StarSlayer on February 27, 2011, 12:28:31 am
Colombia disintegrating during re-entry seems like a significant failure.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 12:33:54 am
Colombia disintegrating during re-entry seems like a significant failure.

That was a failure with the launch system, not the orbiter - the entire ramp assembly was a stupid idea, and (as with Challenger) clearly shouldn't have flown. All the warning signs were there, NASA just ****ed it up. Culture of risk.
Title: Re: Discovery, on final mission, docks with ISS
Post by: StarSlayer on February 27, 2011, 01:04:43 am
Fair enough.

One of the astronuts, Stephen Bowen, is from Mass and served on SSNs in the Navy, so in his words he's been to the deep blue and the dark blue, which I thought was pretty cool.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 01:09:07 am
I mean there are clearly plenty of things wrong with the orbiter and the STS as a whole, but that doesn't stop it from being basically a miracle machine. There are situations where you can argue that your glass is half empty, but when the other half is full of cancer-curing fire-suppressant fat-burning champagne and it tastes good even though it's like 50 Kelvin and you're bathing in the methane seas of Titan, you don't really have a right to complain.

By which I mean that while there are many things wrong with the system as a whole they're basically excused by the fact that it meets an enormous engineering challenge, doesn't blow up every other launch and successfully moves people and machinery into and back from space. Those aren't exactly low requirements - the Russians certainly couldn't meet them.

I'd like to have some badass replacement that is way more economical but it hasn't happened and honestly it's probably not going to.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Kosh on February 27, 2011, 02:29:33 am
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By which I mean that while there are many things wrong with the system as a whole they're basically excused by the fact that it meets an enormous engineering challenge, doesn't blow up every other launch and successfully moves people and machinery into and back from space. Those aren't exactly low requirements - the Russians certainly couldn't meet them.

The Buran and the Soyuz disagree. The real problem with the shuttle design was entirely the fault of the Air Force, who gave up developing their own spaceplane and instead hijacked NASA's next gen spacecraft plans, pushing for features which required costly redesigns (time wise and greatly adding complexity), and in the end we ended up with an overengineered and overly expensive product with said features never being used by the Air Force. Engineering isn't just about meeting challenges, good engineering is about making your designs as simple as possible.

And yes, we should judge the merits of program on its affordibility because that was one of its main selling points. But in addition to needing thousands of people to maintain each of the orbiters (whose salaries greatly drove up the cost of the program), just based on economies of scale it wasn't possible to launch more than two of them in a month because NASA could only build 24 of those big orange fuel tanks a month.

Read about it, in all its details (http://www.astronautix.com/lvs/shuttle.htm)

Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 10:13:20 am
You're now literally linking stuff I read years ago and repeating points you made in your last post. You're not telling me anything I don't know, I just have a different view on the topic than you do.

Judging the merits of the orbiter is separate from judging the merits of the program. There are fantastically overengineered and expensive cars which are completely unsuitable for the task of wide sale to middle-class Americans so they can move their families about. This does not stop them from being amazing pieces of engineering.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Herra Tohtori on February 27, 2011, 11:25:48 am
You shouldn't retire a system until you have something ready to replace it...

From the perspective of space research, retiring the shuttles is bad until something shows up that can do the same job. Unfortunately, like Battuta pointed out, it doesn't seem likely in near future - there is not much commercial or political interest in space flight at the moment, aside from unmanned probes and communications satellites.

Which is very disappointing as a whole. :sigh:
Title: Re: Discovery, on final mission, docks with ISS
Post by: StarSlayer on February 27, 2011, 12:24:23 pm
"DArgo, I havent heard of anything like anything before. My planet doesnt even go to the moon anymore."
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mika on February 27, 2011, 12:33:27 pm
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You shouldn't retire a system until you have something ready to replace it...

...unless the said system was mostly useless in the first place.

Remote controlled vehicles have done a lot of research in the recent years. I don't see the point of sending a man to pick up stones from the surface of the Mars when a robot can do the same with a fraction of the cost and risk. If there were a way to colonize Mars, that would be different, but at the moment the remote controlled missions seem to be a lot more effective.

Upper atmosphere missions then, I don't know. Perhaps fixing satellites could be something that cannot be done with a robot, and that might be a reason to develop a new shuttle. But my understanding of this is that it is a lot more cheaper to build a new satellite and let the old one burn instead of fixing it - and there is only one case where this has been done, that being the Hubble telescope. The telescope was defective from the start though, and that should have been noticed in the testing before it was on the orbit.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 12:36:33 pm
You need at least some kind of manned launch capability for an important reason - you need to study the effects of prolonged time in space on the human body if you're going to have any chance of moving people on long journeys.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Herra Tohtori on February 27, 2011, 01:24:06 pm
The space shuttles are just as mostly useless as Earth is mostly harmless. It's all about the scope of things, and the shuttles have definitely filled a certain niche for heavy lifting and manned space flight that will remain empty in the immediate future. Undoubtedly as soon as need arises, a system will be put together to fulfill requirements. I hope it happens in our life time...
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mika on February 27, 2011, 03:45:16 pm
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The space shuttles are just as mostly useless as Earth is mostly harmless. It's all about the scope of things, and the shuttles have definitely filled a certain niche for heavy lifting and manned space flight that will remain empty in the immediate future. Undoubtedly as soon as need arises, a system will be put together to fulfill requirements. I hope it happens in our life time...

I beg to differ. Shuttle itself is by no means necessary. Presently, rockets can fulfill the cargo lifting cheaper and safer. The cargo can as easily be humans. Actually, I've been wondering why NASA has kept the shuttle program as long as they have. I remember reading that the original plan was to build an assembly line for shuttles and that the final number of the shuttle fleet should have been around 20. What happened is that NASA built 4 prototypes, and each, according to my understanding, requiring slightly different tools. No wonder this approach accumulated costs as the assembly line was never realized.

After each mission, quite a lot of stuff still needs to be renewed from the shuttles so I don't wonder the comments that the shuttles are still in pristine condition. Though the skeptic in me would like to question that too.
Title: Re: Discovery, on final mission, docks with ISS
Post by: NGTM-1R on February 27, 2011, 04:37:54 pm
I beg to differ. Shuttle itself is by no means necessary.

Without the shuttles the ISS would have been much harder to build; they were specifically designed for construction in space. If we were going to do anything besides essentially shut NASA down and pretend space doesn't exist beyond orbit, the shuttles would be the best tool we had for putting together larger things for longer journeys. Even automated equipment could benefit from this.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Kosh on February 27, 2011, 06:38:26 pm
You're now literally linking stuff I read years ago and repeating points you made in your last post. You're not telling me anything I don't know, I just have a different view on the topic than you do.

Judging the merits of the orbiter is separate from judging the merits of the program. There are fantastically overengineered and expensive cars which are completely unsuitable for the task of wide sale to middle-class Americans so they can move their families about. This does not stop them from being amazing pieces of engineering.


The difference between a ferrari and the shuttle is the ferrari isn't intended to make travelling affordable, whereas the shuttle program was mostly sold as the equivalent of that middle class car. Not meeting a critical design requirement like that is a major fail, in fact its high costs are the reason that despite its meddling the Air Force didn't use it.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 27, 2011, 07:50:17 pm
Yeah but if you ask for an affordable middle class car and then James Bond seduces the head of your engineering team and what you end up with is a Ferrari, it's still an amazing piece of engineering even if it's not ideal for the job. The orbiters are the first reusable spacecraft we've ever tried (iirc), none of the orbiters has ever suffered a major failure, and they've helped do a very difficult thing even if some notional alternative might have done it better.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Flipside on February 27, 2011, 08:18:54 pm
Thing is, with the advent of flat-flight spaceplanes, the shuttle was in for a limited life anyway. I agree that it was too soon, and I'll be sorry to see the old bird go, but I don't think we will be long without a re-usable orbital delivery vehicle, especially with China and Russia both developing their own re-usable logistics vehicles. What the US needs is something that can financially threaten the Ariane and other cheaper systems, something like a flat-flight could almost certainly do that.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on February 27, 2011, 11:45:49 pm
i always considered the space shuttle a downgrade from the saturn v booster. the saturn v had a larger lift capacity, was cheaper, and was capable of lifting payloads to much higher orbits. i would have liked to see a winged reusable cargo/crew stage(s) for the saturn, but they developed the shuttle instead.

i cant really bash the shuttle to much because its still somewhat badass what its capable of. but i think after decades of service we need a new ship.
Title: Re: Discovery, on final mission, docks with ISS
Post by: 666maslo666 on February 28, 2011, 03:25:33 am
The most logical and economical thing to do (if politics was not getting in the way of common sense) would be to offsource heavy lifting to ULA (Atlas Phase 2), human crew flights and supply flights to SpaceX (Dragon) or SpaceDev (Dream Chaser), and station manufacturing to Bigelow Aerospace. Obamas plan is better than Constellation, but still could be even better .
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mika on February 28, 2011, 06:27:13 pm
This thread actually lead me to read the accident report on Columbia disaster (248 pages).

The resulting feeling: WTF NASA?!!

After reading the Challenger report and Columbia report, I can't escape the feeling that it might be necessary to overhaul the management of the whole manned space flight program. Especially the Columbia accident report is an eye-opener with regards to the current NASA management style, and the bad thing is that nothing has actually changed since Challenger. Even if several independent reviews earlier have stated this.

I think Obama administration has done once again the right decision by dropping the shuttle. The current shuttles as they are cannot even be made safe, or cheap for that matter.

The concept of space shuttle does beg for an interesting question: is it even possible to achieve the predicted cost saving by using non-expendable vehicle in reality? Would the maintenance costs of a modern day shuttle still be greater than constructing something from the scratch?
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 28, 2011, 06:29:13 pm
The shuttles can easily be made safe, people just need to not be idiots. In both cases of a vehicle loss there were clear warning signs well in advance and the disaster could have been forestalled if proper protocol was followed.

The problem in both cases was NASA culture and tremendous pressure to keep the shuttle flying.

Title: Re: Discovery, on final mission, docks with ISS
Post by: Ghostavo on February 28, 2011, 06:29:54 pm
It all doesn't matter because NASA has finally completed it's true purpose (http://www.theonion.com/articles/nasa-completes-52year-mission-to-find-kill-god,19263/?utm_source=recentnews).
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on February 28, 2011, 06:31:30 pm
aaaaaaahahaha oh god i shouldn't laugh
Title: Re: Discovery, on final mission, docks with ISS
Post by: watsisname on February 28, 2011, 07:03:10 pm
The shuttles can easily be made safe, people just need to not be idiots. In both cases of a vehicle loss there were clear warning signs well in advance and the disaster could have been forestalled if proper protocol was followed.

The problem in both cases was NASA culture and tremendous pressure to keep the shuttle flying.

+1

edit: omg this is an awesome shot
(http://img87.imageshack.us/img87/1072/robbullenissdiscovery26.jpg) (http://img87.imageshack.us/i/robbullenissdiscovery26.jpg/)
Discovery preparing for its final docking with the ISS on Feb 26th.  Photo taken from somewhere in England, ~250 miles away.  :eek2:
Title: Re: Discovery, on final mission, docks with ISS
Post by: NGTM-1R on February 28, 2011, 07:44:47 pm
Tracking to take that shot must have been a proper *****. I don't know if an astrophoto rig could do it.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on February 28, 2011, 10:37:38 pm
The concept of space shuttle does beg for an interesting question: is it even possible to achieve the predicted cost saving by using non-expendable vehicle in reality? Would the maintenance costs of a modern day shuttle still be greater than constructing something from the scratch?

i must point out that i find the entire concept of a "reusable" launch vehicle laughable. almost every launch vehicle has some percentage of recoverability. with mid to heavy sized launch vehicles you almost always get the first stage back. some second stages can be recovered. manned rockets always give you back the capsule. the shuttle tops it where only its fuel tank is non-recoverable, though thats still a rather large construction.

some stages have flyback capability. where the separation occurs before the stage is used up. it throttles back to idle and allows the next stage to separate and clear. then it turns around, throttles up the engine to slow it down with its remaining fuel enough so it doesnt burn up in the atmosphere. its a good idea, because fuel is cheaper than launch vehicles.

i think there would need to be a major breakthrough in engine technology to be able to manage a single stage to orbit vehicle with 100% recoverability. im not saying its impossible, there are some promising engine designs, but until money gets thrown at their development we will never know if they will work or not. furthermore we still need to refurbish and re-certify the vehicle for launch. considering how much recovery technology is available in current rocket designs, i dont see why we just dont stick with rocket-based crew vehicles. a capsule does the job and has a somewhat more reliable thermal protection system, can have a much better abort system, and is better suited to maneuvering in space. dragon certainly does look promising.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mika on March 01, 2011, 05:13:42 am
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The shuttles can easily be made safe, people just need to not be idiots. In both cases of a vehicle loss there were clear warning signs well in advance and the disaster could have been forestalled if proper protocol was followed.

The problem in both cases was NASA culture and tremendous pressure to keep the shuttle flying.

While NASA culture and funding issues are one factor, it actually wasn't unsubstantiated when I said it is unsafe by default. As one of my senior colleagues said, the easiest thing for you to do is to nod and say yes at this point. But since I know how you are going to react to this, here goes:

There are some tiny little fundamental engineering things and also unfortunately physics at play here that should be somewhat obvious after reading the reports. Should I rob the fun of reading and thinking about it yourselves? No, not yet - a scientist should be interested of finding stuff out himself. Actually, I should ask why do you think it actually could be made safe, as that is how it is supposed to be done in space industry?
Title: Re: Discovery, on final mission, docks with ISS
Post by: Kosh on March 01, 2011, 08:43:01 am
Assuming they can get funding for it I think this (http://en.wikipedia.org/wiki/Reaction_Engines_Skylon) is extremely promising, and overall really good engineering if it delivers.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on March 01, 2011, 09:34:33 am
Quote
The shuttles can easily be made safe, people just need to not be idiots. In both cases of a vehicle loss there were clear warning signs well in advance and the disaster could have been forestalled if proper protocol was followed.

The problem in both cases was NASA culture and tremendous pressure to keep the shuttle flying.

While NASA culture and funding issues are one factor, it actually wasn't unsubstantiated when I said it is unsafe by default. As one of my senior colleagues said, the easiest thing for you to do is to nod and say yes at this point. But since I know how you are going to react to this, here goes:

There are some tiny little fundamental engineering things and also unfortunately physics at play here that should be somewhat obvious after reading the reports. Should I rob the fun of reading and thinking about it yourselves? No, not yet - a scientist should be interested of finding stuff out himself. Actually, I should ask why do you think it actually could be made safe, as that is how it is supposed to be done in space industry?

I've already read it - a few months ago. We gamed out the Challenger launch decision in college and the Columbia loss report was one of the documents I went through as research. If it's beyond you that someone might know as much as you and reach a separate conclusion, then as one of my senior colleagues said, you probably don't belong on the Internet or in the scientific establishment.

Space flight is fundamentally unsafe. It will never be made safe; the entire notion that the space industry is intended to make its vehicles safe is a good laugh, and I should've said 'could easily be made safer' rather than 'safe'. The intent is to make them safer. The shuttle might be made safer, but the shuttle's engineered safety tolerances are, as far as I'm concerned, pretty good. Not perfect, but considering the environment, good. The lack of a crew escape option is one of the bigger flaws.

The CAIB itself said it pretty well in a passage I quoted in my own work:

Quote
These recommendations reflect both the Boardʼs strong support for return to flight at the earliest date consistent with the overriding objective of safety, and the Boardʼs conviction that operation of the Space Shuttle, and all human spaceflight, is a developmental activity with high inherent risks.

Now you can argue - with good basis - that the overcomplicated design of the shuttle renders it much more accident-prone than a more robust, simple design like those we'll probably move to next. There's nothing wrong with that argument, the infamous 'white butterfly bolted to a bullet' accusation, and it's probably true. But the will to create a new manned launch system hasn't existed for decades, let alone the money, and I think it's more important to have manned launch capability active and flying than to give up and sit in the gravity well (which is, let's face it, the probable alternative.) The shuttle could be safer for reasons tied into its fundamental design, but I think the benefits of flying it outweigh the benefits of not flying it even when potential crew and vehicle losses are factored in.

The early days of aeronautics were no different. We need to acknowledge that no matter how hard we try we are going to suffer deaths and vehicle losses. We also need to remember that both shuttle losses to date were caused by problems detected well in advance, and are therefore essentially human error rather than engineering failure.

EDIT: and remember (this can be confusing to those who haven't spent a long time discussing the topic) that most of the statements I've made about good condition and good engineering in this thread are about the orbiter. The SRB and tank designs have always been the weak points of the STS complex and you won't find me stepping up to defend them.

EDIT 2: reading back basically all my points are made in, and in concordance with, the CAIB intro
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on March 01, 2011, 09:51:44 am
Actually yeah Mika, looking back through your post history you have a bad habit of calling people idiots (in a very passive-aggressive way) when posting. Please stop, and remember that one of the core rules of a good debate is to always assume the strongest form of your opponent's position.

If you want to call people idiots just say 'you are an idiot', that's much more fun

hugs and kisses
Title: Re: Discovery, on final mission, docks with ISS
Post by: Col. Fishguts on March 01, 2011, 10:34:17 am
Assuming they can get funding for it I think this (http://en.wikipedia.org/wiki/Reaction_Engines_Skylon) is extremely promising, and overall really good engineering if it delivers.

Ah yes, I was trying to remember the name of that project while reading this thread. Granted it's basically a big flying fuel tank with engines strapped on... the concept is very promising and the SABRE engines are a pretty clever design. I'm glad that ESA is currently funding further development of that.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on March 01, 2011, 01:47:08 pm
So I was paging back through CAIB and yeah, the shuttle does not seem to be performing at a safety rate below that of any other launch system:

Quote
Aircraft seldom crash these days, but rockets still fail between two-and-five percent of the time. This is true of just about any launch vehicle – Atlas, Delta, Soyuz, Shuttle – regardless of what nation builds it or what basic configuration is used; they all fail about the same amount of the time. Building and launching rockets is still a very dangerous business, and will continue to be so for the foreseeable future while we gain experience at it.

Of course it might well be performing better than the other launch systems if NASA weren't under so much pressure and so willing to cut corners. Though I'm inclined to blame human psychology as much as anything peculiar to the organization.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Flipside on March 01, 2011, 02:19:30 pm
Also, with that quote, you have to take into account the quantities involved. If a million aircraft fly, and a thousand crash, that's still only one percent. Yes, there's always a risk with the technologies that NASA uses, mostly thanks to the fuel/thrust problem. The more thrust, the more fuel needed, the more fuel carried, the more thrust needed. It's that cycle that needs to be broken before spaceflight can really start looking at going beyond the 'elite' stage.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on March 01, 2011, 03:18:32 pm
Assuming they can get funding for it I think this (http://en.wikipedia.org/wiki/Reaction_Engines_Skylon) is extremely promising, and overall really good engineering if it delivers.

i really like their engine design. and it looks like they have received more funding for their research. and even if it fails to meet expectations as a space worthy engine it still has applications for hypersonic flight.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mika on March 02, 2011, 04:19:23 pm
Quote
Actually yeah Mika, looking back through your post history you have a bad habit of calling people idiots (in a very passive-aggressive way) when posting. Please stop, and remember that one of the core rules of a good debate is to always assume the strongest form of your opponent's position.

If you want to call people idiots just say 'you are an idiot', that's much more fun

I will start with this one. I don't call anyone idiot in real life, and that applies to the internet discussion too. Doing that doesn't make anything "fun", it will usually only serve to make things worse. And I apply that core rule when I don't know enough from the person who I'm talking/writing to.

Then to the topic:
Quote
Space flight is fundamentally unsafe. It will never be made safe; the entire notion that the space industry is intended to make its vehicles safe is a good laugh, and I should've said 'could easily be made safer' rather than 'safe'. The intent is to make them safer. The shuttle might be made safer, but the shuttle's engineered safety tolerances are, as far as I'm concerned, pretty good. Not perfect, but considering the environment, good. The lack of a crew escape option is one of the bigger flaws.

and this one are actually partially related.

Quote
EDIT: and remember (this can be confusing to those who haven't spent a long time discussing the topic) that most of the statements I've made about good condition and good engineering in this thread are about the orbiter. The SRB and tank designs have always been the weak points of the STS complex and you won't find me stepping up to defend them.

I, in principle, agree with these statements, but there is one thing missing that I feel hasn't been discussed much. There is one thing in the orbiter tolerances themselves that when combined with the tank design is outright a dangerous combination. That is the reinforced carbon carbon panel impact resistance combined with the external tank shedding its isolation foam. Even though the panels are likely a couple of magnitudes stronger than required, this is not enough to withstand almost a supersonic impact of an object that might have mass counted in kilograms rather than grams. I'm starting to think that nothing that would be put in the orbit could be.

The underlying problem is the shuttle launching procedure in itself, the orbiter is not sitting on top of the external tank where the isolation foam would have a much lower probability of hitting it. It is instead fixed on the lower part of the solid rocket boosters and the external tank. And I also think that it is almost impossible in the current knowledge of Physics to put isolation foam on the tank that would remain there with sufficient certainty, considering the influence of the environment. It is no coincidence that aircraft wings should really be kept clean, and the orbiter is no exception - things are only more demanding with the orbiter. The insulation foam of the tank cannot be got rid off in the current design. It is needed to prevent ice from getting on the tank surfaces, ice would cause even more problems than the foam should it fall on the orbiter during ascent. If Russians and Chinese are going to go with reusable vehicles, it will be interesting to see if they go on with a shuttle like configuration or change it somehow to prevent this issue.

Why do I make such a big number of it? In the report, it is said that almost every tenth of the shuttle missions have documented foam shedding and hitting the heat shielding. This means that there is actually some probability that at least every tenth mission could end like Columbia, and there is quite a little that can be done to improve this. Different insulation foam combinations have been tried, but that hasn't got rid of the problem. Also add in that the shuttles are prototypes, each one built slightly differently, both of reports criticize NASA for calling it operational vehicle when it has never been. The problem with foam shedding might be fundamentally unsolvable, and for that reason I think it might not be a bad decision to end the shuttle program.

As a clarification I don't think that the orbiter is badly engineered (it is more on the overall design requirements that were flawed), but as someone who does some amount of engineering I put more value on how well the systems achieve their performance requirements, where the shuttle is unfortunately a failure. It would be interesting to hear how do the engineers themselves think about the shuttle in private, though I haven't yet met one from NASA.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on March 02, 2011, 04:21:50 pm
I don't see anything in there that disagrees with any point I've raised in this thread.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on March 02, 2011, 05:17:05 pm
i dont think it would be wise to return to a shuttle in the current configuration. capsules can be much safer but what i would like to see is a winged crew vehicle, much smaller than the shuttle with no cargo capacity. it would only contain everything needed for crew operations and return and can be placed at the top of the rocket stack. missions that require cargo would place the crew vehicle on top of a cargo stage, much like how the lm was stowed in apollo. still a capsule would be better suited to maneuver cargo and could have a much simplified and therefore more reliable thermal protection system. i figure either capsule or winged crew vehicle could have abort capability.
Title: Re: Discovery, on final mission, docks with ISS
Post by: General Battuta on March 02, 2011, 05:41:13 pm
If it's economical I think the ideal option (assuming multistage is still basically a requirement) would be a two-part reusable design with a launch aircraft that piggybacks the orbiter up to its breakaway and orbital burn.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on March 02, 2011, 06:23:09 pm
i like the idea of high altitude launches, though it does limit the size and payload of the launch vehicle to what the carrier aircraft can take off with. this might fill in the small to medium launch roles, and even potentially crew launches, but you arent going to be doing any heavy payload liftoff with such a system. you're better off with a heavy launch vehicle in this case.

i do kinda think crew launches should be done with smaller craft though, would be much safer. on heavy space construction missions, yea you're better off lifting the cargo off separately. the only thing that requires crew and cargo in the same launch right now is cost, and if itts to be done this way id like to see the crew vehicle at the top of the stack where it can abort and not risk getting hit by debris.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mars on March 02, 2011, 06:35:23 pm
Didn't I hear an idea involving a really big railgun once?
Title: Re: Discovery, on final mission, docks with ISS
Post by: Flipside on March 02, 2011, 06:38:42 pm
Yup, that was considered for unmanned work, also there's still the Space Elevator on the horizon, which would be ideal for sending up standard payloads, or even for building space-vehicles in orbit, thus eliminating the need for any launcher system at all, but it's still a good few years before it's viable from what I understand.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on March 02, 2011, 06:42:29 pm
Yup, that was considered for unmanned work, also there's still the Space Elevator on the horizon, which would be ideal for sending up standard payloads, or even for building space-vehicles in orbit, thus eliminating the need for any launcher system at all, but it's still a good few years before it's viable from what I understand.

and we still need a counterweight. i say we should find a way to capture apophis, land some arrays of srbs on the thing and put it into geosync.
Title: Re: Discovery, on final mission, docks with ISS
Post by: 666maslo666 on March 03, 2011, 05:16:18 am
Quote
i dont think it would be wise to return to a shuttle in the current configuration. capsules can be much safer but what i would like to see is a winged crew vehicle, much smaller than the shuttle with no cargo capacity. it would only contain everything needed for crew operations and return and can be placed at the top of the rocket stack.

Something like Dream Chaser shuttle currently being developed?  :yes:

http://en.wikipedia.org/wiki/Dream_Chaser_(spacecraft)
 

Indeed makes a lot of sense, imho.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Nuke on March 03, 2011, 05:40:02 am
Quote
i dont think it would be wise to return to a shuttle in the current configuration. capsules can be much safer but what i would like to see is a winged crew vehicle, much smaller than the shuttle with no cargo capacity. it would only contain everything needed for crew operations and return and can be placed at the top of the rocket stack.

Something like Dream Chaser shuttle currently being developed?  :yes:

http://en.wikipedia.org/wiki/Dream_Chaser_(spacecraft)
 

Indeed makes a lot of sense, imho.

ah yes thats the craft i was thinking of, couldnt draw a name but i remember seeing a concept pic.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Mongoose on March 03, 2011, 02:30:59 pm
Yeah, I think separating out the crew-carrying and heavy cargo roles is definitely the best way to go in the future.  One of the fundamental problems with the space shuttle's design is that it mashed both of those roles together, and we've seen how the resultant issues have played out in the past.  Still, for all of its rightly-acknowledged flaws, the shuttle is an amazing piece of engineering, and I'm going to sorely miss it when it's put to bed.  I got to see the Enterprise at the Udvar-Hazy Smithsonian annex at Dulles Airport a few years ago, but I think it's going to be replaced by Discovery when it's retired, so it'll be awesome to get the chance to see her too.  It'd be awesome to figure out a way to see one of the final two launches, too.
Title: Re: Discovery, on final mission, docks with ISS
Post by: Scourge of Ages on March 09, 2011, 11:48:44 am
Well, she's landed. http://news.yahoo.com/s/ap/us_space_shuttle

Yesterday, at around 7:30 local time, they both flew over my town, and I done watched 'em. One of the final orbits ever of Discovery. It was cool.
Title: Re: Discovery, on final mission, docks with ISS
Post by: carbine7 on March 09, 2011, 01:25:57 pm
Yeah, I saw them too last night as they orbited overhead, one of them about a minute behind the other. It was really cool to watch, yet also sentimental.