Future Robotic Shuttles?

Jeff Findley wrote in
:

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.
Nor really. What destroyed Challenger was NASA's decision to ignore the
engineers. Had a liquid fuel booster phisicaly collapse on the side of
the ET would have caused the same scenario.

It lowered design costs, but opened up the system design to
the possibility of catastrophic failure due to the unique failure
modes of large segmented solid rocket boosters. At least with liquids
you can safely shut them down without adding complex, often
pyrotechnic activated, thrust termination systems (which have their
own failure modes).
Assuming there would be enough time to thottle down both LRB's and the
shuttle's engines in a coordinated way.

A side question: if you blow the top of the SRBs while going several
times the speed of sound, doesn't it still work as an engine ? Or is
the pressure differential too great for air to be forced in from the top
?

Columbia was also a launch failure in my book because the damage to
the orbiter's TPS was caused during the launch.
At the time the foam hit the wing it was probably to late to abort the
launch, but probably not to late for a return to launch site abort.

The root cause of the damage was foam shedding from the ET.
I'd say the root cause was a wing edge that isn't up the launch
environment. You can get rid of the foam and get ice instead.

Foam shedding was treated like a
maintenance issue but should have been treated as a safety issue all
along. Foam shedding from the ET wasn't adequately addressed until
after the Columbia disaster. Actually, the program to reduce shedding
foam has been largely successful. Had such a program been implemented
early in the shuttle program, a Columbia like failure would have been
far less likely.
Escape from a Columbia-like problem would have to be addressed by an
escape pod and a pre-reentry decision to ditch the vehicle or at least
to return empty (buran-style), and here we have more tons of "useless"
items on-board.

A launch escape system may not have helped the Columbia crew, since
the damage went unnoticed during the launch and depending on the
details a *launch* escape system may not be suitable for use during
reentry.
That would be a given since launch escape systems seem designed to do
only one thing: get the crew capsule well away from the about-to-explode
stack. On re-entry you have no stack to speak of.

It's easy to say in hindsight that such a system should be designed to
work during reentry, but I don't think that observation would have
been obvious during the shuttle development.
Adding a crew capsule to the shuttle would reduce it's
already-defficient cargo capability (reinforced structures, half a ton
of detonating cord and an SRB).

On Oct 17, 10:00*am, Jose Pina Coelho wrote:
Jeff Findley wrote :

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.

Nor really. *What destroyed Challenger was NASA's decision to ignore the
engineers. *Had a liquid fuel booster phisicaly collapse on the side of
the ET would have caused the same scenario.

It lowered design costs, but opened up the system design to
the possibility of catastrophic failure due to the unique failure
modes of large segmented solid rocket boosters. *At least with liquids
you can safely shut them down without adding complex, often
pyrotechnic activated, thrust termination systems (which have their
own failure modes).

Assuming there would be enough time to thottle down both LRB's and the
shuttle's engines in a coordinated way.

A side question: *if you blow the top of the SRBs while going several
times the speed of sound, doesn't it still work as an engine ? *Or is
the pressure differential too great for air to be forced in from the top
?

Columbia was also a launch failure in my book because the damage to
the orbiter's TPS was caused during the launch.

At the time the foam hit the wing it was probably to late to abort the
launch, but probably not to late for a return to launch site abort.

The root cause of the damage was foam shedding from the ET.

I'd say the root cause was a wing edge that isn't up the launch
environment. *You can get rid of the foam and get ice instead.

Foam shedding was treated like a
maintenance issue but should have been treated as a safety issue all
along. *Foam shedding from the ET wasn't adequately addressed until
after the Columbia disaster. *Actually, the program to reduce shedding
foam has been largely successful. *Had such a program been implemented
early in the shuttle program, a Columbia like failure would have been
far less likely.

Escape from a Columbia-like problem would have to be addressed by an
escape pod and a pre-reentry decision to ditch the vehicle or at least
to return empty (buran-style), and here we have more tons of "useless"
items on-board.

A launch escape system may not have helped the Columbia crew, since
the damage went unnoticed during the launch and depending on the
details a *launch* escape system may not be suitable for use during
reentry.

That would be a given since launch escape systems seem designed to do
only one thing: get the crew capsule well away from the about-to-explode
stack. *On re-entry you have no stack to speak of.

It's easy to say in hindsight that such a system should be designed to
work during reentry, but I don't think that observation would have
been obvious during the shuttle development.

Adding a crew capsule to the shuttle would reduce it's
already-defficient cargo capability (reinforced structures, half a ton
of detonating cord and an SRB).

EXCELLENT POST! On how both losses were unavoidable.........

if the challeger crew had the originally designed jettisonable crew
compartment those astronauts would probably be alive today.

and such a compartment may have survived the columbia break up.

with no launch boost escape the shuttle should of never been man rated

In article ,
says...

Jeff Findley wrote in
:

Take a closer look at the shuttle. There are many failure modes on the
shuttle which can be fixed by astronauts, but can't be fixed remotely
from the ground.
How many of those failure modes are directly related to being a crewed
and/or reusable vehicle ?

Crewed, not as many as you might think. Reusable, quite a few. For
example, if you want to get your expensive shuttle back and can't close
the payload bay doors remotely, the fix is to send an astronuat on an
EVA to fix the problem. Considering each shuttle cost billions to
build, that's not an asset you want to lose.

Take a look at the list of possible contingency EVA's on the shuttle and
you'll quickly find that the sorts of failures these address would turn
into loss of vehicle without a crew present.
In the history of the shuttle, how many times was is saved by having an EVA
?

Loss of vehicle can be a danger to people on the ground.
Having a crewed cargo vehicle voids the "blow it up over the ocean" option.

Not really. The shuttles have *always* lived with this possibility. If
the shuttle stack goes out of control while the SRB's are burning, and
it looks like it is becoming a danger to anyone on the ground, range
safety would "push the button", which would "terminate the SRB thrust"
by firing destruct charges which run the length of the SRB's. The
shuttle cannot safely separate from the stack while the SRB's are
burning, so this would result in loss of vehicle and crew.

In other words, just because the shuttle has a crew on board, doesn't
mean that it is immune from being destroyed if it endangers, so called,
innocent people on the ground.

Jeff
--
42

In article ,
says...

Jeff Findley wrote in
:

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.
Nor really. What destroyed Challenger was NASA's decision to ignore the
engineers. Had a liquid fuel booster phisicaly collapse on the side of
the ET would have caused the same scenario.

I disagree. Burn through was more likely at lower temperatures, but o-
ring erosion was found on *many* flights. It was a danger which could
have destroyed a shuttle and crew even if management listened and the
launched during warmer weather. The SRB field joints had several issues
that needed addressed. In other words, the initial design was "not
good".

Note that the SRB joint fixes involved *a lot* more than adding heaters
to the joints to keep the o-rings warm during cold weather.

It lowered design costs, but opened up the system design to
the possibility of catastrophic failure due to the unique failure
modes of large segmented solid rocket boosters. At least with liquids
you can safely shut them down without adding complex, often
pyrotechnic activated, thrust termination systems (which have their
own failure modes).
Assuming there would be enough time to thottle down both LRB's and the
shuttle's engines in a coordinated way.

A side question: if you blow the top of the SRBs while going several
times the speed of sound, doesn't it still work as an engine ? Or is
the pressure differential too great for air to be forced in from the top
?

You can terminate the thrust of an SRB by opening a big hole at the top.
It actually terminates the burning because the propellant will stop
burning once the chamber pressure drops. This option was considered for
the shuttle design. Unfortunately it was found that the transient
forces involved would have destroyed the orbiter. So, the decision was
made to run a linear charge along the entire length of the SRB in order
to open up the case along its length. This option was simpler to design
and was very reliable at the same time.

Columbia was also a launch failure in my book because the damage to
the orbiter's TPS was caused during the launch.
At the time the foam hit the wing it was probably to late to abort the
launch, but probably not to late for a return to launch site abort.

The root cause of the damage was foam shedding from the ET.
I'd say the root cause was a wing edge that isn't up the launch
environment. You can get rid of the foam and get ice instead.

The best design would have put the shuttle on top of the stack so
nothing would be above it to create any hazard due to falling foam, ice,
or anything else. As you point out, it really doesn't matter what hits
the leading edge.

Foam shedding was treated like a
maintenance issue but should have been treated as a safety issue all
along. Foam shedding from the ET wasn't adequately addressed until
after the Columbia disaster. Actually, the program to reduce shedding
foam has been largely successful. Had such a program been implemented
early in the shuttle program, a Columbia like failure would have been
far less likely.
Escape from a Columbia-like problem would have to be addressed by an
escape pod and a pre-reentry decision to ditch the vehicle or at least
to return empty (buran-style), and here we have more tons of "useless"
items on-board.

A launch escape system may not have helped the Columbia crew, since
the damage went unnoticed during the launch and depending on the
details a *launch* escape system may not be suitable for use during
reentry.
That would be a given since launch escape systems seem designed to do
only one thing: get the crew capsule well away from the about-to-explode
stack. On re-entry you have no stack to speak of.

It's easy to say in hindsight that such a system should be designed to
work during reentry, but I don't think that observation would have
been obvious during the shuttle development.
Adding a crew capsule to the shuttle would reduce it's
already-defficient cargo capability (reinforced structures, half a ton
of detonating cord and an SRB).

It would take a heck of a lot more than that to change the crew capsule
into "an escape capsule". Plus, this was to be a reusable vehicle with
"airline like operations". Aircraft don't have escape capsules.
Passenger airliners don't have parachutes for the people on board. The
design philosophy here is to make sure the vehicle has intact abort
modes throughout the flight envelope.

Unfortunately, the shuttle never truly had intact abort modes.

Jeff
--
42

In article 0a4664f7-56c4-4f70-95de-ec9e596be110
@j2g2000yqf.googlegroups.com, says...

EXCELLENT POST! On how both losses were unavoidable.........

if the challeger crew had the originally designed jettisonable crew
compartment those astronauts would probably be alive today.

Too heavy to make a reality on a reusable design like the shuttle.
Better to include intact abort modes throughout the flight environment
and augment the abort system with better health monitoring systems.

And finally, don't use large segmented solid rocket boosters on launch
vehicles. They have catastrophic failure modes which tend to happen
fast and without warning. SRB's are at odds with a "safety first"
philosophy.

and such a compartment may have survived the columbia break up.

with no launch boost escape the shuttle should of never been man rated

By that reasoning, we should never "man rate" passenter aircraft because
we don't provide passengers parachutes. It's a bad argument for a
vehicle if it provides intact abort throughout the flight environment.
The shuttle didn't truly have intact abort modes. Separation of the
orbiter from the stack during SRB burn was never survivable.

Jeff
--
42

On 10/18/2010 07:36 AM, Jeff Findley wrote:
In ,
says...

Jeff wrote in
:

Loss of vehicle can be a danger to people on the ground.
Having a crewed cargo vehicle voids the "blow it up over the ocean" option.

Not really. The shuttles have *always* lived with this possibility. If
the shuttle stack goes out of control while the SRB's are burning, and
it looks like it is becoming a danger to anyone on the ground, range
safety would "push the button", which would "terminate the SRB thrust"
by firing destruct charges which run the length of the SRB's. The
shuttle cannot safely separate from the stack while the SRB's are
burning, so this would result in loss of vehicle and crew.

In other words, just because the shuttle has a crew on board, doesn't
mean that it is immune from being destroyed if it endangers, so called,
innocent people on the ground.

This applies even after SRB sep, when the stack no longer has a flight
termination system. Under the Flight Rules, the CDR and PLT "BECOME
AGENTS OF THE 45 SW COMMANDER FOR PUBLIC SAFETY DURING THE PORTION OF
FLIGHT AFTER SOLID ROCKET BOOSTER SEPARATION AND PRIOR TO MAIN ENGINE
CUTOFF." For an imminent range safety MECO line violation during second
stage, the abort request switches at the FD, FDO, and FCO consoles send
commands to illuminate the ABORT light on the flight deck. The required
crew response is to perform a manual MECO.

So far so good (you can find these rules at the STS-107 FOIA page at:

http://www.jsc.nasa.gov/news/columbia/fr_generic.pdf

starting on p. 985). The part these rules leave unsaid is that the crew
is expected to perform the manual MECO even if it leaves the orbiter in
a known contingency abort 3-out black zone, from which survival of the
orbiter down to safe bailout condition is not expected.

Jeff Findley wrote in
:

In article ,
says...

Jeff Findley wrote in
:

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.
Nor really. What destroyed Challenger was NASA's decision to ignore
the engineers. Had a liquid fuel booster phisicaly collapse on the
side of the ET would have caused the same scenario.

I disagree. Burn through was more likely at lower temperatures, but
o- ring erosion was found on *many* flights. It was a danger which
could have destroyed a shuttle and crew even if management listened
and the launched during warmer weather. The SRB field joints had
several issues that needed addressed. In other words, the initial
design was "not good".
Yes, having hot gas pushing the o-rings away from the sealing position
made my jaw drop.

In fact, a lot of the CAIB report made my jaw drop.

[...]
It would take a heck of a lot more than that to change the crew
capsule into "an escape capsule".
If would be impossible to change it. It could only be designed as such
from the start.

Plus, this was to be a reusable vehicle with "airline like operations".
Did anyone believe that one (other than a few senators, and top-
management) ? Even the most optimist scenario of x number of flights per
year would clearly mark it as "totaly unlike airline".

Aircraft don't have escape capsules.
F-111 Aardvark, but then again, with a name like that you would expect it
to be different. :-), and the B-58 with individual capsules.

Passenger airliners don't have parachutes for the people on board.
That's because any egress solution that doesn't include 500 ejection
seats will make sure that 90% of the passengers won't leave the aircraft
before it hits the ground.

The design philosophy here is to make sure the vehicle has
intact abort modes throughout the flight envelope.

On 10/21/2010 05:50 PM, Jose Pina Coelho wrote:
Jeff wrote in
:

In ,
says...

Jeff wrote in
:

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.
Nor really. What destroyed Challenger was NASA's decision to ignore
the engineers. Had a liquid fuel booster phisicaly collapse on the
side of the ET would have caused the same scenario.

I disagree. Burn through was more likely at lower temperatures, but
o- ring erosion was found on *many* flights. It was a danger which
could have destroyed a shuttle and crew even if management listened
and the launched during warmer weather. The SRB field joints had
several issues that needed addressed. In other words, the initial
design was "not good".
Yes, having hot gas pushing the o-rings away from the sealing position
made my jaw drop.

In fact, a lot of the CAIB report made my jaw drop.

Umm, the CAIB report covered Columbia, not Challenger.

Aircraft don't have escape capsules.
F-111 Aardvark, but then again, with a name like that you would expect it
to be different. :-), and the B-58 with individual capsules.

They also had pretty lousy records for actually saving the crew.

On Oct 21, 9:27*pm, "Jorge R. Frank" wrote:
On 10/21/2010 05:50 PM, Jose Pina Coelho wrote:





Jeff *wrote in
:

In ,
says...

Jeff *wrote in
:

[...}
What destroyed Challenger was the design decision to use large
segmented solid rocket boosters instead of liquids for the parallel
staged boosters.
Nor really. *What destroyed Challenger was NASA's decision to ignore
the engineers. *Had a liquid fuel booster phisicaly collapse on the
side of the ET would have caused the same scenario.

I disagree. *Burn through was more likely at lower temperatures, but
o- ring erosion was found on *many* flights. *It was a danger which
could have destroyed a shuttle and crew even if management listened
and the launched during warmer weather. *The SRB field joints had
several issues that needed addressed. *In other words, the initial
design was "not good".
Yes, having hot gas pushing the o-rings away from the sealing position
made my jaw drop.

In fact, a lot of the CAIB report made my jaw drop.

Umm, the CAIB report covered Columbia, not Challenger.

Aircraft don't have escape capsules.
F-111 Aardvark, but then again, with a name like that you would expect it
to be different. :-), and the B-58 with individual capsules.

They also had pretty lousy records for actually saving the crew.- Hide quoted text -

- Show quoted text -

well the shuttle is worse than flying in combat and most military
airplanes have ejection seats.

theres no escape system on commercial airliners since most accidents
occur during takeoff or landing, and theres no way to get out during
those times

In article 96dd767b-f54d-41e2-ba37-2a55cd6d8d89
@j18g2000yqd.googlegroups.com, says...

well the shuttle is worse than flying in combat and most military
airplanes have ejection seats.

Worse than flying in combat? No Bob, that's NOT true. Shuttle has only
had two failures in 132 flights, which is a 1 in 66 loss of crew rate.
That's a heck of a lot better than what our boys were facing during WW-
II.

My grandfather was an engineer on a B-24 during WW-II and the life
expectancy of one of an air crew was extremely dismal and they had no
ejection seats (they did have parachutes though). I know you can't
always trust the Internet for facts like this, but here it is anyway:

Bomber crews' tour of duty was 25 missions (later raised to 35)
But, the life expectancy of the average crew was just 14 missions.

Most NASA astronauts only fly one or five missions. There is a *very*
small minority who have flown six or more missions. No NASA astronaut
has flown anywhere near the 25 or 35 missions required to complete a WW-
II bomber crew's tour.

Obviously, the actual risk to a single shuttle astronaut is *far* lower
than that of a WW-II bomber crew, who flew together on every one of
those missions until one of two things stopped them: 1. They were shot
down (most likely all killed) or 2. They completed their tour of duty
and went home.

If you're going to make wild assertions that may offend combat veterans
and their families, please back up that assertion with facts and
verifiable statistical analyses.

theres no escape system on commercial airliners since most accidents
occur during takeoff or landing, and theres no way to get out during
those times

Most launch vehicle accidents occur during launch or reentry/landing
too. You take your chances during launch and landing, and every
astronaut knows those odds and chooses to fly anyway. Just because some
whiners like you don't like the odds is no reason to stop flying.

Jeff
--
42