Britain's longest aircraft runway ?

Britain's longest aircraft runway ?

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Discussion

Vaud

50,287 posts

154 months

Thursday 29th January 2015
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Foliage said:
I'm surprised to see no abort to ISS listed or was that never a possibility?
How would you get there? Not enough spare fuel to suddenly change orbit, too much complication and then you have more stranded crew and constraints on systems, oxygen, etc. If you have achieved a stable orbit, then just return to planned landing but ahead of time. If the orbit is too low or not stable, you are aborting.

Not sure how the ISS would help?

anonymous-user

53 months

Thursday 29th January 2015
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Foliage said:
I'm surprised to see no abort to ISS listed or was that never a possibility?
or an abort to the moon? or some other planet.

Eric Mc

121,770 posts

264 months

Thursday 29th January 2015
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Foliage said:
I'm surprised to see no abort to ISS listed or was that never a possibility?
If you want to reach a target in earth orbit, then you have to have a take off path that is alligned with the orbital path of that target.

If a Space Shuttle was being launched on a mission that did not involve docking with the Space Station (or Mir - in earlier years), then there was no way that it could change its alligned take off trajectory after launch to match that of the space station. All it could do would be to limp on up into an orbit which would allow the crew and mission control some thinking time before deciding whether the Shuttle needed to land or whether it could continue with its mission as best it could.

In the 135 flight record of the Shuttle, there was one Abort To Orbit (ATO) which occurred on mission STS-51F in July 1985.

Foliage

3,861 posts

121 months

Thursday 29th January 2015
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Sorry should have been clearer, (I know how orbital mechanics work, fuel loads etc, I understand that if the shuttle was for example placing a satellite in a different orbit to the ISS (especially orbital plane) then the constraint of fuel would prohibit an inclination change or a bi-elliptic/Hofmann transfer.

I was thinking mainly if a shuttle was either up servicing or delivering to the ISS and a Columbia style situation happen and the shuttle was flyable but not capable of re-entry. I was just curious if that had been planned for, and was in fact surprised it wasn't mentioned on wikipedia, I don't know as much about space as id like too.


Eric have you ever played Kerbal Space Program?

Eric Mc

121,770 posts

264 months

Thursday 29th January 2015
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I never play Kerbal (I spend too much time in front of computer screens as it is).

If a Shuttle was being launched on a mission to the ISS and it had a problem that meant an ATO was the best solution, there is a possibility that it MIGHT be able to continue on to the ISS. That would depend on the nature of the problem.

The only ATO that did occur (the one I mentioned) put the Shuttle in a lower orbit than it was intended to achieve on that mission. This did not have a significant impact on the mission objectives - but if it had been intended to rendezvous and dock with another orbiting spacecraft - such as the ISS - it would not have been able to make it to the altitude required.

As an aside, Columbia could never be used for Mir or ISS missions because it was incapable of reaching the altitude of those two stations. Columbia was just too heavy.


aeropilot

34,295 posts

226 months

Thursday 29th January 2015
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MarkwG said:
AAGR said:
What does anyone think of the proposal that the northern runway at Heathrow should effectively be doubled in length, though it will really be end-to-end runways with a safety 'neutral zone' in the middle ?

How long will that all be, in total ?
Anything's doable: the procedures would need to be pretty clear as to what to do in the event of the unexpected. There's benefits to be had, whether they out weigh the problems created, not sure. I'm not sure I'd want to be the first airport in the world to try it though. Total length of both would be in excess of 16km.
Not to mention the fact they will have to bridge over the M25 (or tunnel M25 under).......

I know it's to placate the NIMBY's from Harmondsworth and Sipson, but the seperate 3rd runway to the north would still be the most logical option (Harmondsworth and Sipson could do with being bulldozed anyway hehe)


MarkwG

4,810 posts

188 months

Saturday 31st January 2015
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aeropilot said:
Not to mention the fact they will have to bridge over the M25 (or tunnel M25 under).......

I know it's to placate the NIMBY's from Harmondsworth and Sipson, but the seperate 3rd runway to the north would still be the most logical option (Harmondsworth and Sipson could do with being bulldozed anyway hehe)
The plan accounts for that: not technically difficult, similar have been built elsewhere. However, I doubt it'll come to that; as you say, there are better answers anyway.

mph1977

12,467 posts

167 months

Saturday 31st January 2015
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Celtic Dragon said:
Mildenhall has to be up there too, they landed Air Force One on it!
which performance wise is a fairly standard 747...

aeropilot

34,295 posts

226 months

Saturday 31st January 2015
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mph1977 said:
Celtic Dragon said:
Mildenhall has to be up there too, they landed Air Force One on it!
which performance wise is a fairly standard 747...
Indeed...hehe

Far more 'runway critical' types than a boring old 747 were operated from the 'hall.


saaby93

32,038 posts

177 months

Saturday 31st January 2015
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aeropilot said:
I know it's to placate the NIMBY's from Harmondsworth and Sipson, but the seperate 3rd runway to the north would still be the most logical option (Harmondsworth and Sipson could do with being bulldozed anyway hehe)
smash
Some people from Harmondsworth (and Sipson) helped build Heathrow in their back yard.
Other available runways have already been listed yes

vescaegg

25,489 posts

166 months

Sunday 1st February 2015
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How come the shuttle needs such a long runway? Does it come into land like seriously fast compared to planes? Can it not brake as efficiently? Is it huge compared to a plane?

red_slr

17,122 posts

188 months

Sunday 1st February 2015
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I guess the fact you cant try a second time means the longer the better.

Vaud

50,287 posts

154 months

Sunday 1st February 2015
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No reverse thrusters either.

Super Slo Mo

5,368 posts

197 months

Sunday 1st February 2015
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vescaegg said:
How come the shuttle needs such a long runway? Does it come into land like seriously fast compared to planes? Can it not brake as efficiently? Is it huge compared to a plane?
Yes, very fast compared to a plane.

Vaud

50,287 posts

154 months

Sunday 1st February 2015
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http://www.nasa.gov/mission_pages/shuttle/launch/l...

Landing speed of 214-226 mph... a 747 is 130-160 IIRC.

MartG

20,620 posts

203 months

Sunday 1st February 2015
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Vaud said:
http://www.nasa.gov/mission_pages/shuttle/launch/l...

Landing speed of 214-226 mph... a 747 is 130-160 IIRC.
With no thrust reverse to help slow down, just brakes initially, then they later added a parachute

Eric Mc

121,770 posts

264 months

Sunday 1st February 2015
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And no reverse thrust either (no engines). The braking parachute system was only introduced after the Challenger accident.

The Shuttle didn't have nose wheel steering. It steered using differential braking on the main wheels (like on a Lancaster bomber). This often put undue strain on the brakes - especially in even modest crosswinds. And on one occasion they suffered a tyre explosion cases by the brakes overheating. The tyre debris from the tyre burst damaged dozens of the thermal protection tiles.

Prawo Jazdy

4,944 posts

213 months

Sunday 1st February 2015
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https://www.youtube.com/watch?v=kkjDr5-I5-s

Video quality seems to have come from 1974 rather than 2009, but it shows you the Shuttle approach. It's what a scientist would describe as "really, very steep indeed".

dr_gn

16,140 posts

183 months

Sunday 1st February 2015
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Eric Mc said:
The Shuttle didn't have nose wheel steering.
I doubt that's right: It would mean a failiure in either main gear brakes (or tyres) would then render the thing effectively out of control at lower speeds on the runway.

Eric Mc

121,770 posts

264 months

Sunday 1st February 2015
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dr_gn said:
I doubt that's right: It would mean a failiure in either main gear brakes (or tyres) would then render the thing effectively out of control at lower speeds on the runway.
From NASA website -


"The first landing at KSC was Mission 41-B on Feb. 11, 1984. KSC was the landing site for four of the next six missions. Extensive brake damage and a blown tire at the conclusion of the 51-D mission in April 1985 prompted officials to postpone further KSC landings until nose wheel steering and improved brakes were installed in the orbiters. Landings were scheduled to resume at KSC with Mission 61-C in January 1986, but that flight also was diverted to EAFB due to bad weather in Florida. The Space Shuttle Challenger accident less than two weeks later resulted in renewed concerns about safety, weather and runway conditions. KSC landings again were put on hold".

The Orbiter was originally designed with no nosewheel steering capability of any sort.

Following the blown tyre incident (which extensively damaged the thermal protections system) and an overall review of Shuttle safety after the Challenger accident, a LIMITED nosewheel steering capability was added. It was still not very effective and the Orbiter was always very vulnerable in even the slightest crosswind conditions. A lot of landings were postponed due to unacceptable crosswinds at the designated landing sites.
The main direction control during the landing roll out was always the use of differential braking on the mainwheels.