ATK Plans Commercial Ares I

On Fri, 11 Apr 2008 01:48:06 GMT, in a place far, far away, Brian
Thorn made the phosphor on my monitor glow
in such a way as to indicate that:

On Thu, 10 Apr 2008 15:56:00 GMT, h (Rand
Simberg) wrote:


Further thoughts:

http://www.transterrestrial.com/arch...resh_hell.html

a. The SRB's record is 1 failure in 244 launches. Really, what first
stage has a better track record?

Irrelevant.

(I know, you're saying "it's not
about reliability", but try telling THAT to Congress... "Senator, we
are going with a Delta-based launcher... yes, we know its already had
one failure, but this isn't about reliability...")

b. The present SRB is not the same design that destroyed Challenger.
(You imply that it is.)

Then we have no idea how reliable it is.

c. Ares's SRB will be neither design, but closer to the current one
than the Challenger one.

d. The SRB's one failure was a slow-onset failure affording plenty of
time for launch escape, had the data been monitored in real time (even
if not, it is possible Smith saw the disaster happening in time to
have pulled an abort handle, if he'd had one) and a launch escape
system been available.

Again, it's not about reliability. As a commercial vehicle, this
thing would be a dog.

wrote in message
...
See:

http://www.aviationweek.com/aw/gener...98.xml&show=us

I wonder how well that's going to work out.

Poorly.

It's a bad idea for a government paid for project. Now they're talking
further upgrades, which will only make it MORE expensive.

Ain't gonna happen.

"Rick Jones" wrote in message
...
Jeff Findley wrote:
In the early 60's every type of launch vehicle was pretty dangerous.
But times change. Over the history of the shuttle program, there
have been zero catastrophic SSME events in all those flights. But
there was one, very notable, catastrophic SRB event.

Wouldn't that be more accurately described as SRB+ET event?

There was never a requirement that the ET needed to be able to sustain a
blowtorch to its side during flight. Since the blowtorch was coming from
the SRB, I place the blame squarely on the SRB. The ET would never have
failed had it not been for the malfunctioning SRB.

Also, if the leak was away from the ET, it's entirely possible that the leak
could have gotten big enough that the increasing thrust imbalance between
the SRB's would have caused loss of control of the stack. Again, this would
have been an SRB failure, not a control system failure as the control system
was never intended to handle SRB's whose thrust way out of balance.

In fact, the SRB's fuel is cast in pairs of casings from a single batch of
fuel so that one can be used on the left SRB and one on the right SRB so
that their burn characteristics will be as close as possible. Leaking
joints definitely goes against the requirement to have the thrust of the two
SRB's be as closely matched as possible.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

"Brian Thorn" wrote in message
...
On Fri, 11 Apr 2008 00:53:45 +0000 (UTC), Rick Jones
wrote:

Wouldn't that be more accurately described as SRB+ET event?
No. SRB was the cause - the ET was just in the way of the plume.

So the same thing would have happened if the plume had been going away
from the ET?

Yep. The plume spread all the way around the circumference by the end.
Control authority and thrust imbalance would have become severe issues
in short order, as well. It just would have taken a little longer.

Add that to the fact that it's pretty much suicide to command a separation
of the orbiter from the stack while the SRB's are firing. The orbiter and
crew were in deep trouble no matter where the joint leak initially started.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

"Brian Thorn" wrote in message
...
On Thu, 10 Apr 2008 15:56:00 GMT, h (Rand
Simberg) wrote:


Further thoughts:

http://www.transterrestrial.com/arch...resh_hell.html

a. The SRB's record is 1 failure in 244 launches. Really, what first
stage has a better track record? (I know, you're saying "it's not
about reliability", but try telling THAT to Congress... "Senator, we
are going with a Delta-based launcher... yes, we know its already had
one failure, but this isn't about reliability...")

One of the failure modes of large segmented solids is a rapid rupture of the
casing. This failure mode would result in loss of vehicle and crew, even
for an Orion equipped with a launch escape system.

The worst failure modes of liquid engines aren't nearly as bad as the worst
failure modes of large segmented solids. So even if the reliability of the
liquid stage can be proven to be worse, the survivability would still likely
be better.

b. The present SRB is not the same design that destroyed Challenger.
(You imply that it is.)


True. The SRB for Ares I now bears little resemblance to the SRB's used on
the shuttle, so you can't say their failure rate will be similar, even
though ATK and NASA would like to believe this is true.

c. Ares's SRB will be neither design, but closer to the current one
than the Challenger one.

Some of the thrust oscillation "fixes" being proposed impact the SRB design,
further distancing the design from the current shuttle design. Furthermore,
"fixes" proposed to increase the payload of Ares I (like an additional 1/2
segment, changing the propellant, and composite casings) pretty much change
the design enough that it really is an all new stage.

d. The SRB's one failure was a slow-onset failure affording plenty of
time for launch escape, had the data been monitored in real time (even
if not, it is possible Smith saw the disaster happening in time to
have pulled an abort handle, if he'd had one) and a launch escape
system been available.

But that's not the only failure mode of large segmented solids. Remember
the Titan that went "boom". Casing failure is a failure mode that's not
considered survivable. ATK admitted this in their "safe, simple, soon"
proposal that very closely resembles Ares I.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

"Greg D. Moore (Strider)" wrote in message
news
wrote in message
...
See:

http://www.aviationweek.com/aw/gener...98.xml&show=us

I wonder how well that's going to work out.

Poorly.

It's a bad idea for a government paid for project. Now they're talking
further upgrades, which will only make it MORE expensive.

Ain't gonna happen.

It looks like this "announcement" is designed to gain political support for
the Ares I program. Because without Ares I, ATK is afraid that shuttle/Ares
SRB production will stop, which will hurt their bottom line.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

"Jeff Findley" wrote:


"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:
My guess is, not well considering the vibration issues with Ares I.

I always wonder how this group would have reacted had it existed back
in the early 60's...

In the early 60's every type of launch vehicle was pretty dangerous. But
times change. Over the history of the shuttle program, there have been zero
catastrophic SSME events in all those flights. But there was one, very
notable, catastrophic SRB event.

Um, so what? We aren't discussing catastrophic failures of a flying
vehicle, but rather vibration problems with a vehicle being designed.
(Or more correctly Pronouncing The Vehicle Doomed because of them.)

And even if it is solvable to the satisfaction of commercial customers, that
still doesn't mean that commercial customers have much motivation to pick
Ares I over a Delta IV Heavy (or even an Atlas V Heavy). That is, unless
the government starts subsidizing Ares I launches like it did with the
shuttle.

You have the costs of the Ares IC(ommercial)? Do share please!

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"Jeff Findley" wrote:


"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:
My guess is, not well considering the vibration issues with Ares I.

I always wonder how this group would have reacted had it existed back
in the early 60's...

In the early 60's every type of launch vehicle was pretty dangerous. But
times change. Over the history of the shuttle program, there have been zero
catastrophic SSME events in all those flights. But there was one, very
notable, catastrophic SRB event.

Now to address this issue: One failure in 244 flights (122 Shuttle
launches X 2 SRB's per flight).. 1/244 = .0041 or 99.5% reliability
for the Stick, comfortably at or above what is currently acceptable.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:


"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:
My guess is, not well considering the vibration issues with Ares I.

I always wonder how this group would have reacted had it existed back
in the early 60's...

In the early 60's every type of launch vehicle was pretty dangerous. But
times change. Over the history of the shuttle program, there have been
zero
catastrophic SSME events in all those flights. But there was one, very
notable, catastrophic SRB event.

Um, so what? We aren't discussing catastrophic failures of a flying
vehicle, but rather vibration problems with a vehicle being designed.
(Or more correctly Pronouncing The Vehicle Doomed because of them.)

Certainly there was a lot of testing at the time to set limits on things
like vibrations. I don't think that vibrations which would impair the
crew's ability to function would not be tolerated, let alone vibrations
which could potentially injure the crew.

And even if it is solvable to the satisfaction of commercial customers,
that
still doesn't mean that commercial customers have much motivation to pick
Ares I over a Delta IV Heavy (or even an Atlas V Heavy). That is, unless
the government starts subsidizing Ares I launches like it did with the
shuttle.

You have the costs of the Ares IC(ommercial)? Do share please!

Like I said, it pretty much depends on what NASA would decide. I'm assuming
Michoud would still build the tanks for the upper stage and that KSC
facilities would still be used for assembly and launch. Certainly
commercial flights of the shuttle were overly subsidized. Customers weren't
charged anywhere near that actual reoccurring costs of a shuttle flight.
The difference was paid by the US taxpayers.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein

"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:


"Derek Lyons" wrote in message
...
"Jeff Findley" wrote:
My guess is, not well considering the vibration issues with Ares I.

I always wonder how this group would have reacted had it existed back
in the early 60's...

In the early 60's every type of launch vehicle was pretty dangerous. But
times change. Over the history of the shuttle program, there have been
zero
catastrophic SSME events in all those flights. But there was one, very
notable, catastrophic SRB event.

Now to address this issue: One failure in 244 flights (122 Shuttle
launches X 2 SRB's per flight).. 1/244 = .0041 or 99.5% reliability
for the Stick, comfortably at or above what is currently acceptable.

I'd say that level of reliability would be at or above what is currently
acceptable for a commercial launch. Unfortunately, that level of
reliability applies to the four segment SRB as used in the shuttle
configuration, not the five segment SRB used in the Ares I configuration.
Because of the performance and vibration problems with Ares I, other changes
are being proposed by ATK to increase performance. The more changes made,
the shuttle numbers become less applicable.

And we can't forget the upper stage, which will use a new engine design
which is based on a (lower performance) design that hasn't flown since the
1970's. So all bets are off when it comes to the reliability of the upper
stage.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein