The Space Shuttle - Quite complicated!
Discussion
The trouble with the Shuttle is that it was totally a political machine.
NASA was prevented from building the Shuttle they actually wanted by severe budgetary constraints and the need to accommodate the very different requirements of the US Department of Defense. Effectively, they had a gun to their heads. Congress more or told them that they HAD to build a bigger, heavier, more aerodynamically capable vehicle than they really wanted - or they were out of the manned spaceflight business - possibly forever.
Everything about the way the Shuttle was designed and built stems from this situation.
If we want to talk about the nitty gritty of the technology involved in the vehicle and the tank and boosters, you need to bear all this in mind.
Where do we want to start?
The hold down bolts is as good a place as any. NASA looked at the hinged lock down system that was used on the Saturn V and decided it wasn't appropriate. I think it was because those type of hold downs reacted too slowly compared to the pyrotechnic bolt system they eventually settled on. This is because the Shuttle accelerated far more quickly off the pad compared to the larger, heavier Saturn V.
The hold downs on the Saturn V had to wait for the five F1 engines to build up to maximum thrust before releasing the rocket. On the Shuttle, you had instant maximum thrust as soon as those Solids fired. Therefore, the lock downs had to react far more quickly.
Also, the Shuttle went through the "twang" mode immediately after the three Shuttle main engines (SSME) were lit - due to the off-centre angle of those engine bells (which was needed to prevent the exhaust plume from the Shuttle's engines impinging on the External Tank).
Those hold down bolts had to fire the microsecond the whole stack returned to the vertical. Again, the Apollo style hinged hold downs would have been too slow to react to the "twang".
Although there were always concerns about the consequences of what would happen if the pyros failed to fire correctly (instant destruction of the vehicle), the system behaved very reliably throughout the 135 missions flown.
NASA was prevented from building the Shuttle they actually wanted by severe budgetary constraints and the need to accommodate the very different requirements of the US Department of Defense. Effectively, they had a gun to their heads. Congress more or told them that they HAD to build a bigger, heavier, more aerodynamically capable vehicle than they really wanted - or they were out of the manned spaceflight business - possibly forever.
Everything about the way the Shuttle was designed and built stems from this situation.
If we want to talk about the nitty gritty of the technology involved in the vehicle and the tank and boosters, you need to bear all this in mind.
Where do we want to start?
The hold down bolts is as good a place as any. NASA looked at the hinged lock down system that was used on the Saturn V and decided it wasn't appropriate. I think it was because those type of hold downs reacted too slowly compared to the pyrotechnic bolt system they eventually settled on. This is because the Shuttle accelerated far more quickly off the pad compared to the larger, heavier Saturn V.
The hold downs on the Saturn V had to wait for the five F1 engines to build up to maximum thrust before releasing the rocket. On the Shuttle, you had instant maximum thrust as soon as those Solids fired. Therefore, the lock downs had to react far more quickly.
Also, the Shuttle went through the "twang" mode immediately after the three Shuttle main engines (SSME) were lit - due to the off-centre angle of those engine bells (which was needed to prevent the exhaust plume from the Shuttle's engines impinging on the External Tank).
Those hold down bolts had to fire the microsecond the whole stack returned to the vertical. Again, the Apollo style hinged hold downs would have been too slow to react to the "twang".
Although there were always concerns about the consequences of what would happen if the pyros failed to fire correctly (instant destruction of the vehicle), the system behaved very reliably throughout the 135 missions flown.
So, what do you want to discuss? I'm happy to chat about the technical aspects of the design. Or does nobody really want to discuss the Shuttle on a Shuttle discussion thread?
It was a fascinating machine. That MIT lecture series is by far and away the most extensive thing I've ever come across that really gets to the nitty gritty of how it worked, its strengths and its weaknesses etc - all described by people who worked intimately on the programme.
It was a fascinating machine. That MIT lecture series is by far and away the most extensive thing I've ever come across that really gets to the nitty gritty of how it worked, its strengths and its weaknesses etc - all described by people who worked intimately on the programme.
Eric Mc said:
So, what do you want to discuss? I'm happy to chat about the technical aspects of the design. Or does nobody really want to discuss the Shuttle on a Shuttle discussion thread?
It was a fascinating machine. That MIT lecture series is by far and away the most extensive thing I've ever come across that really gets to the nitty gritty of how it worked, its strengths and its weaknesses etc - all described by people who worked intimately on the programme.
Thanks for the link, watched the first lecture tonight, very interesting. It was a fascinating machine. That MIT lecture series is by far and away the most extensive thing I've ever come across that really gets to the nitty gritty of how it worked, its strengths and its weaknesses etc - all described by people who worked intimately on the programme.
I come from a background of IT projects that have budgets of 10 - 100 million (small beans compared to the projected shuttle budget) and was amazed to hear Dale Myers say that he'd questioned (internally) the suitability of the design in light of the new defence requirements but didn't question it externally as it could result in the end of the project - similar to Chaffe (I think) saying how he couldn't question the Apollo 1 CSM wiring. Is that indicative of lessons not learnt and existing in an environment where your professional obligations become diametrically opposed to you personal aims and dreams?
I would never dare to question the capability or professional rigour that these guys apply (suppose I just have!), but I'd love to know why it wasn't questioned further if not through fear of the loss of a dream.
I would never dare to question the capability or professional rigour that these guys apply (suppose I just have!), but I'd love to know why it wasn't questioned further if not through fear of the loss of a dream.
I think fear of completely losing manned spaceflight capability made the important people at NASA far less likely to question some of the requirements and changes they were being forced to incorporate into the design.
The analogy with Apollo 1 is interesting because one of the chief people involved in the design of the Apollo Command and Service Module (CSM) was Dale Myers - who spent a large part of his professional life working for North American Aviation - who were building the CSM.
The analogy with Apollo 1 is interesting because one of the chief people involved in the design of the Apollo Command and Service Module (CSM) was Dale Myers - who spent a large part of his professional life working for North American Aviation - who were building the CSM.
The irony of the entire US manned space program was that it was primarily designed to show the communists how great capitalism was, yet it was one of the biggest centrally-planned, government funded projects the world has ever known. Is it any surprise that the encore was another expensive, sub-optimal b
d child?
d child?Well, it was the imposition of "capitalistic" elements - such as extremely tight budgets - and the requirement to work in an "economic" way that dictated what the Shuttle ended up looking like - and dictated what its engineering flaws were going to be.
Ironically, the inefficient, wasteful Commie spacecraft (Soyuz) is still going strong and may well have turned out to be a much more economically viable method of putting humans into earth orbit.
Ironically, the inefficient, wasteful Commie spacecraft (Soyuz) is still going strong and may well have turned out to be a much more economically viable method of putting humans into earth orbit.
It's wrong to assume that Soviet communism didn't have to deal with money, budgets and a supply chain. Communism was just the state telling everyone what the priorities were and what you had to do. On that basis, the US manned space program was just as communist, if not more so, than the communists...
Edited by AER on Thursday 8th January 00:49
AER said:
It's wrong to assume that Soviet communism didn't have to deal with money, budgets and a supply chain. Communism was just the state telling everyone what the priorities were and what you had to do. On that basis, the US manned space program was just as communist, if not more so, than the communists...
Spot on and to think the Russians are lesser is a big mistake, I have seen the results of Russian software some of which has come from Star City and its quite awesome Edited by AER on Thursday 8th January 00:49
AER said:
The irony of the entire US manned space program was that it was primarily designed to show the communists how great capitalism was, yet it was one of the biggest centrally-planned, government funded projects the world has ever known. Is it any surprise that the encore was another expensive, sub-optimal bd child?
It was the R101 when what was wanted was the R100.d child?To suggest that the shuttle programme was political misses the point I think. Everything about manned spaceflight was political. The success of the shuttle must be measured not on its scientific targets but on those of the politicians. If it did what they wanted then it was a total failure. If it didn't then it was an abject failure, even had they discovered aliens and a monolith on the Moon.
Once the iron curtain came down, manned spaceflight had little purpose, at least according to its paymasters.
Did the Russians expend a higher proportion of the GDP on their manned space programme? Did the Americans appear to be technically superior? Were a number of spy satellites put up into orbit? Did it gain votes for those who could jump on the bandwagon? Did those who objected to the expenditure gain votes? These are the most important targets for the manned space programme and to suggest scientific research was mentioned is wrong.
Thought I'd resurrect this rather contentious thread because I found some interesting interviews with Dr Feynman on you tube about the Shuttle project -
https://www.youtube.com/watch?v=4kpDg7MjHps
https://www.youtube.com/watch?v=4kpDg7MjHps
I'm not saying we won't see a reusable space plane. In fact, I expect to see one within the next five years (Dream Chaser).
However, we will not see anything as large, as grandiose or as complex as the NASA Space Shuttle and we certainly won't see one where the orbiter element sits straddling a large cryogenic tank.
However, we will not see anything as large, as grandiose or as complex as the NASA Space Shuttle and we certainly won't see one where the orbiter element sits straddling a large cryogenic tank.
There's a film about Richard Feynman's investigation called "The Challenger Disaster", with William Hurt as Feynman.
http://www.imdb.com/title/tt2421662/?ref_=nm_flmg_...
I saw it a couple of years ago and it's not bad. Worth a watch.
http://www.imdb.com/title/tt2421662/?ref_=nm_flmg_...
I saw it a couple of years ago and it's not bad. Worth a watch.
Foliage said:
In one of your previous post on this thread eric you mention that you don't think we will ever see a vehicle like the space shuttle again, still feel that or do you think that technology and attitudes have moved on in the last 2 years?
Better ask Richard Branson that one http://www.virgingalactic.comGassing Station | Science! | Top of Page | What's New | My Stuff