Dear Space Shuttle Launch-Abort Experts

What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an RLTS?
Do they simulate it in training? How much better are the computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?

On Thu, 12 Aug 2004 12:10:46 -0500, Cardinal Vertigo
wrote:

What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an RLTS?
Do they simulate it in training? How much better are the computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?

It is flown successfully in simulators quite often. It will be hairy,
and require nothing ELSE to go wrong (i.e., another engine failure)
but it should be successful. No miracles rqeuired, just backup plans
and systems working the way they're supposed to.

Brian

Cardinal Vertigo wrote:
What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an
RLTS? Do they simulate it in training? How much better are the
computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?


The earliest RTLS could occur is a little over 2 minutes into the
flight, after the solid rocket boosters have separated. So whatever
happened can't get much worse for at least that long.

The shuttle/external tank needs to be able to pitch around, nose tilting
up and back toward the launch site, and keep thrusting with the
remaining main engines (they are still working, right?), use up all but
a dash of fuel/oxidizer from the tank, while essentially flying
backwards to stop the forward motion, but still gaining enough altitude
to have a chance to glide back home, after jettisoning the tank and
sidestepping it to avoid a collison.

Piece of cake. Like teaching a manatee to break dance.


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Brian Thorn wrote:

On Thu, 12 Aug 2004 12:10:46 -0500, Cardinal Vertigo
wrote:

What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an RLTS?
Do they simulate it in training? How much better are the computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?

It is flown successfully in simulators quite often. It will be hairy,
and require nothing ELSE to go wrong (i.e., another engine failure)
but it should be successful. No miracles rqeuired, just backup plans
and systems working the way they're supposed to.

Have procedures been developed to land an orbiter which has another
major failure during RTLS, or would the crew just try to ditch?

--
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sweat of its laborers, the genius of its scientists, the hopes of
its children."
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In article , Cardinal Vertigo
wrote:

What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an RLTS?
Do they simulate it in training? How much better are the computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?

What's an RTLS? Is it anything like a BLTS?

pbls

What's an RTLS? Is it anything like a BLTS?

pbls

return to launch site abort. light solids, when they burn out you turn the
vehicle around and attempt to get back to the KSC landing strip. Its a very
risky manuver and a long time ago I heard its success chance is less than 10%

I think a ditch in the ocean is safer for the crew.
HAVE A GREAT DAY!

"bob haller" wrote in message
...

What's an RTLS? Is it anything like a BLTS?

pbls

return to launch site abort. light solids, when they burn out you turn the
vehicle around and attempt to get back to the KSC landing strip. Its a
very
risky manuver and a long time ago I heard its success chance is less than
10%

I think a ditch in the ocean is safer for the crew.

Where did you hear "less than 10%"?

Ditching in the ocean is near certain suicide for the crew, especially since
any launch carries a payload in the bay and ditching with a full payload bay
makes ditching much more dangerous for the crew.

RTLS allows the crew a fighting chance to actually land the shuttle safely.
I doubt it is as bad as you're making it out to be, but it is risky enough
that NASA never wanted to test it.

Actually, NASA never tested any launch abort flight profiles before
declaring the shuttle "operational". This is not a good sign for a
"reusable" system. Properly designed reusable systems ought to allow for
incremental testing as well as testing of abort situations.

Jeff
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Remove icky phrase from email address to get a valid address.

polar bear wrote:

In article , Cardinal Vertigo
wrote:

What are the rough chances of an RTLS abort being necessary on any given
launch? What are a pilot's chances of being able to manually fly an RLTS?
Do they simulate it in training? How much better are the computers' chances?

The "popular wisdom" is that even a computer-controlled RTLS requires at
least eight miracles in quick succession. How accurate is that perception?

What's an RTLS? Is it anything like a BLTS?

No.

It's "Return To Launch Site," which is a way to get the orbiter on a
runway at Kennedy in under 30 minutes after launch if something goes
very, very wrong.

It's pretty wild.

http://www.theandyzone.com/launchzone/rtlsp1.htm

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On 2004-08-13, Jeff Findley wrote:

Ditching in the ocean is near certain suicide for the crew, especially since
any launch carries a payload in the bay and ditching with a full payload bay
makes ditching much more dangerous for the crew.

Suicide for all the crew? Remember, there's no requirement they be on
board when it ditches...

If you have a ditchable orbiter, and manage to fly it reasonably stably
as you come in to ditch, you should be able to have a reasonable number
of crew bail out into the water (possibly all, depending). This isn't
the safest pastime, but not that suicidal...

(I suppose this might count as "abandoned over the ocean", though)

--
-Andrew Gray

"Andrew Gray" wrote:
On 2004-08-13, Jeff Findley wrote:

Ditching in the ocean is near certain suicide for the crew, especially
since
any launch carries a payload in the bay and ditching with a full payload
bay
makes ditching much more dangerous for the crew.

Nevertheless it was the only choice for operational flights prior to STS 26
and all flight crews were briefed on ditching and had some limited practice
for this highly undesirable escape opportunity.

Suicide for all the crew? Remember, there's no requirement they be on
board when it ditches...

All ditching scenarios put together by NASA that I have seen specifically
included the concept that the crew stayed with the orbiter during the
ditching. This was because all of those scenarios include the fact that the
crew was in shirt sleeves at the time (up until Challenger STS 51-L). Only
the Orbital Flight Tests allowed for your scenario via ejection seats which
were installed for the first four flights. Post STS 51-L, ditching has not
been in the cards at all. Studies have made it abundantly clear that only a
miracle would allow for crew survival in an ocean ditching on anything other
than a glassy smooth ocean. Miracles do however happen from time to time.

If you have a ditchable orbiter, and manage to fly it reasonably stably
as you come in to ditch, you should be able to have a reasonable number
of crew bail out into the water (possibly all, depending). This isn't
the safest pastime, but not that suicidal...

Yes and NASA practices this Abort Mode from time to time. It is Abort Mode
VIII. It is quite fascinating actually and for a real launch the resuce
plan involves a small air fleet to handle the potential bail out at various
downrange distances.

(I suppose this might count as "abandoned over the ocean", though)

It would be a gliding flight bail out (usually controlled).

Daniel