Space Shuttle - NASA Commemorative Vid - Moving Footage!

[NDA]

Just watching some of that - how does the shuttle maintain the correct attitude when it's still attached to the rockets and 'stack'? The shuttle looks to have a very small amount of wing in comparison to the bulk of the stack and I wondered how it controls itself so it doesn't head off on a peculiar angle.

[Eric Mc]

The rocket nozzles are gimballed (free to rotate around their attachment point. On board gyros make slight adjustments to the nozzle positions to keep the whole thing balanced and pointing in the right direction. The wings are of no use watsoever during the launch phase. Indeed, they are a hindrance as they represent aerodynamic load problems and are effectively dead weight.

This is one of the problems with the Shuttle. A lot of spacefaring capability (payload lifting, altitude, flexibility once in orbit etc)was sacrificed on the altar of the ability to glide to a landing on a runway.

[Simpo Two]

M-J-B said:

Simpo Two said:

For 'pinnacle of achievement' I'd vote Apollo 11 (and also 13) ahead of the Shuttle.

Due to achievement all those years of complexity of equipment?

The criterion is achievement. I think it's more of an achievement to get to the Moon and back on a glorified V2 armed only with a pocket calculator and 1960s technology, than manage mere Earth orbit with 40 terawotsits of computing power and 21st Century technology. Apollo was 'pushing the envelope' far more than the Shuttle ever did IMHO.

Edited by Simpo Two on Monday 13th December 11:55

[Eric Mc]

Although you do need to realise that the Shuttle started out with 1970s technology as well. The original Shuttle onboard computers were based on hardware and software "frozen" in 1975.

Obviously, numerous uopgrades were made in the 30 years of operations.

[M-J-B]

Simpo Two said:

M-J-B said:

Simpo Two said:

For 'pinnacle of achievement' I'd vote Apollo 11 (and also 13) ahead of the Shuttle.

Due to achievement all those years of complexity of equipment?

The criterion is achievement. I think it's more of an achievement to get to the Moon and back on a glorified V2 armed only with a pocket calculator and 1960s technology, than manage mere Earth orbit with 40 terawotsits of computing power and 21st Century technology. Apollo was 'pushing the envelope' far more than the Shuttle ever did IMHO.

Edited by Simpo Two on Monday 13th December 11:55

Including Eric's next post re the computer technology used in the early Shuttle's, I would still agree with you.

Having watched a number of programmes over the years, there is no doubt the Apollo spacecraft were on the cutting edge of technology and a hairsbreadth away from disaster. I recall one astronaut suggesting he always thought he had less than 30% chance of mission success and coming home alive (and another was refused life insurance due to his choice of career!)

[jmorgan]

There were many things that could go wrong but I think the system that was in place for Apollo was up to the job. Thinking what the odds were and what actually happened were different. 27 (?) went around the moon, 12 landed on it. All returned.


Edit. That is up to the job considering the risks with rockets and stuff.

Edited by jmorgan on Monday 13th December 12:38

[M-J-B]

jmorgan said:

There were many things that could go wrong but I think the system that was in place for Apollo was up to the job. Thinking what the odds were and what actually happened were different. 27 (?) went around the moon, 12 landed on it. All returned.


Edit. That is up to the job considering the risks with rockets and stuff.

Edited by jmorgan on Monday 13th December 12:38

It was clearly 'up to the job', but how close was it to 'not being up to the job'?

[jmorgan]

Well, 13 problem was from 10. Nearly ended in disaster. 10 had issues on ascent from its test. 12 had a strike and so on but in all cases there were very intelligent men on board with a very clued up mission control. I don't think they would have knowingly gone on a suicide mission.

[M-J-B]

jmorgan said:

I don't think they would have knowingly gone on a suicide mission.

I think that they would have looked at the maths and taken a calculated gamble.

[jmorgan]

They did not just land in the hot seat. There was a lot of work before they went. The whole process was tried and tested so they knew what to expect. Reading some of the biographies when they first tried rendezvous for example. They had to think hard and train for it. Linking up and manoeuvring or just the space walk. How much fuel was used or nearly died but for the grace of a trained astronaut. It was more than the maths.

[M-J-B]

jmorgan said:

They did not just land in the hot seat. There was a lot of work before they went. The whole process was tried and tested so they knew what to expect. Reading some of the biographies when they first tried rendezvous for example. They had to think hard and train for it. Linking up and manoeuvring or just the space walk. How much fuel was used or nearly died but for the grace of a trained astronaut. It was more than the maths.

No, you misunderstand, I didn't mean they literally did sums! They were pioneers and by virtue of their character would look at the entire mission and take a calculated gamble. They were test pilots and such, and used to danger and the probability of not coming home one day. But they almost certainly would give it a go even if the chances were less than 50% (which according to one astronaut, they were).

It goes without saying they were highly trained professional personnel, but there were still massive risks.

[jmorgan]

That is what I thought you meant but not come across from me. I will have to reaquint myself with the percentage quote and context (I am thinking at the moment it was a reference to actually landing and not disaster, memory is dim on this) but if you were to ask Gene Cernan you would obviously get a different answer to Neil Armstrong as you would Jim Lovell.

[NDA]

Eric Mc said:

The rocket nozzles are gimballed (free to rotate around their attachment point. On board gyros make slight adjustments to the nozzle positions to keep the whole thing balanced and pointing in the right direction. The wings are of no use watsoever during the launch phase. Indeed, they are a hindrance as they represent aerodynamic load problems and are effectively dead weight.

This is one of the problems with the Shuttle. A lot of spacefaring capability (payload lifting, altitude, flexibility once in orbit etc)was sacrificed on the altar of the ability to glide to a landing on a runway.

Interesting - thanks...... So the 'stack' (that being a separate item to the shuttle) sort of flies independently?

I had often wondered how they achieved it and had assumed the stack was just a pair of rockets with no guidance.

[M-J-B]

NDA said:

Eric Mc said:

The rocket nozzles are gimballed (free to rotate around their attachment point. On board gyros make slight adjustments to the nozzle positions to keep the whole thing balanced and pointing in the right direction. The wings are of no use watsoever during the launch phase. Indeed, they are a hindrance as they represent aerodynamic load problems and are effectively dead weight.

This is one of the problems with the Shuttle. A lot of spacefaring capability (payload lifting, altitude, flexibility once in orbit etc)was sacrificed on the altar of the ability to glide to a landing on a runway.

Interesting - thanks...... So the 'stack' (that being a separate item to the shuttle) sort of flies independently?

I had often wondered how they achieved it and had assumed the stack was just a pair of rockets with no guidance.

Eric, do the solid rockets gimble or just the Shuttle rockets (I thought just the three Shuttle rockets)?

[Eric Mc]

Both the SRB nozzles and the three Shuttle Main Engines (SMEs) all gimble to keep the whole thing on course. The "stack" refers to everything - the two SRBs, the tank and the Oribiter.

Most rockets have gimballing engine bells to steer the rocket and keep it on course. The V2 and Redstone used steerable graphite vanes placed in the rocket exhaust which acted as thrust deflectors.
Von Braun had wanted to use a gimballing engine bell but decided that it was too advanced for 1940s thechnology so went with the simpler vane system instead.

Edited by Eric Mc on Monday 13th December 17:11

[NDA]

Mystery solved.... I've often wondered how they kept it pointing in the right direction before separation.

[rufusruffcutt]

Great video.

I like how you can watch "the twang" in slow motion where once the orbiters engines are up and running it bends the whole stack over. Once the stack bends back to the upright position the solid rocket boosters then fire.
Its about 16:30 to 17:40 move your mouse backwards and forwards on the video time-line to see it clearly.