Instant Shuttle turnaround ?

This is a rethorical question, so no need to spout insults about how
unrealistic, unsafe it would be. I am more interested in the raw
mechanics of it. (and a "one off" exploit, not doing the stuff below all
the time).

If, just after landing, they were to clean up the cabin, refuel the
tanks, inflate tires and then mate an orbiter to a stack and launch it.

What orbiter systems would not work because they *absolutely* need to be
changed with each flight ?

What systems would have a high likelyhood of failure ?

What systems would likely work ?

What systems would definitely work ?


Would it be fair to state that the cabin systems, computers etc would
not *require* any refit between flights ? (ok, so they need to change
the CO2 filters and clean toilet).

Would SSMEs work ? Or do they become absolutely inoperative after being
iddle in vaccum and/or re-entry ? Is it correct to state that they were
originally designed to be re-used without maintenance ?

What about all the thrusters around the orbiter ? Do they gunk up during
re-entry and require maintenance, or are they theoretically ready to be
used again ?

On Dec 3, 10:24�am, John Doe wrote:
This is a rethorical question, so no need to spout insults about how
unrealistic, unsafe it would be. I am more interested in the raw
mechanics of it. (and a "one off" exploit, not doing the stuff below all
the time).

If, just after landing, they were to clean up the cabin, refuel the
tanks, inflate tires and then mate an orbiter to a stack and launch it.

What orbiter systems would not work because they *absolutely* need to be
changed with each flight ?

What systems would have a high likelyhood of failure ?

What systems would likely work ?

What systems would definitely work ?

Would it be fair to state that the cabin systems, computers etc would
not *require* any refit between flights ? �(ok, so they need to change
the CO2 filters and clean toilet).

Would SSMEs work ? Or do they become absolutely inoperative after being
iddle in vaccum and/or re-entry ? �Is it correct to state that they were
originally designed to be re-used without maintenance ?

What about all the thrusters around the orbiter ? Do they gunk up during
re-entry and require maintenance, or are they theoretically ready to be
used again ?

APUs need lots of service after any turn on......

it would make flying a lot less safe......

main engines were originally designed for complete rebuild after each
flight, they have a high ISP nand run right on the edge.

over the years better materials have decreased the frequency oof
rebuild every time

let al;one fixing all the tile damage, and every flight has some.
sadly we know what danger bad TPS is

its been discussed before, a 2nd generation shuttle could be built
using modern materials, replacing hydrazine etc that would make flying
less costly and turn around times shorter........

John Doe wrote in
:

This is a rethorical question, so no need to spout insults about how
unrealistic, unsafe it would be. I am more interested in the raw
mechanics of it. (and a "one off" exploit, not doing the stuff below
all the time).

The SSMEs are normally pulled and subject to a detailed inspection;
this may require a partial disassembly. These engines have been tested
to multiple firings without inspection, but NASA is being conservative.
Yeah, a set of inspected SSMEs could be on standby to install, but
that'll take a few days; lots of leak checks are required, for example.

The heat shield tiles apparently require detailed inspection, some
repairs, and "recaulking" of the gaps between the tiles; I think this
is "normal" but unavoidably essential maintenance that prevents a
fast turnaround because of the man-hours required.

I don't know about the hydrazine APUs and hydraulic systems; seems that
the thrusters and OMS should be good for a quick turnaround if there
were no problems on the previous flight. Most other systems not using
fluids should be good to go if there were no failures requiring analysis
and repairs--NASA needs to have a good reason to fly without redundant
systems.

Since the Shuttle's main mission is ISS assembly and support, with a lot
of planning and preparation between flights, there doesn't seem to be
a pressing need for fast turnarounds. Given that there are very few
other reasons to fly Shuttle, again a fast turnaround doesn't seem to be
essential.

If you're postulating an emergency situation, isn't a Shuttle stack on
standby or the ISS a 'safe haven" until a Shuttle can be prepared for
a rescue flight?

My guess is that a "fast turnaround" is going to require at least a few
days or even weeks; Shuttle was originally supposed to have a two-week
turnaround but that's never even remotely worked in practice.

Would a "new generation" Shuttle have a shorter turnaround, if new or
improved systems were available? Probably, but it depends on the
individual systems--particularly the thermal protection system has been
very sensitive and requiring detailed inspection and maintenence. A
different type of technology seems essential for the TPS, perhaps a
whole new Shuttle design fundamentally different from the existing
system.

There's no lack of proposed reusable spacecraft/launch systems, but I'm
guessing a couple more generations of engineering and development will
be required to get turnarounds remotely similar to routine airline
operations.

It'll happen when there's a need for it.

--Damon

"Damon Hill" wrote in message
...
John Doe wrote in
:

This is a rethorical question, so no need to spout insults about how
unrealistic, unsafe it would be. I am more interested in the raw
mechanics of it. (and a "one off" exploit, not doing the stuff below
all the time).

The SSMEs are normally pulled and subject to a detailed inspection;
this may require a partial disassembly. These engines have been tested
to multiple firings without inspection, but NASA is being conservative.
Yeah, a set of inspected SSMEs could be on standby to install, but
that'll take a few days; lots of leak checks are required, for example.


I have an email someplace that indicates that they're basically at the point
of flying I think 3-5 missions with minor inspections before a tear down.
So this may not be an issue.


The heat shield tiles apparently require detailed inspection, some
repairs, and "recaulking" of the gaps between the tiles; I think this
is "normal" but unavoidably essential maintenance that prevents a
fast turnaround because of the man-hours required.


This is probably a big one, but I believe they have a 'robot' that helps
quite a bit here also (at least in the inspection part)


I don't know about the hydrazine APUs and hydraulic systems; seems that
the thrusters and OMS should be good for a quick turnaround if there
were no problems on the previous flight. Most other systems not using
fluids should be good to go if there were no failures requiring analysis
and repairs--NASA needs to have a good reason to fly without redundant
systems.


The APUs and OMS systems are probably the longest poles in the tent.

Since the Shuttle's main mission is ISS assembly and support, with a lot
of planning and preparation between flights, there doesn't seem to be
a pressing need for fast turnarounds. Given that there are very few
other reasons to fly Shuttle, again a fast turnaround doesn't seem to be
essential.

If you're postulating an emergency situation, isn't a Shuttle stack on
standby or the ISS a 'safe haven" until a Shuttle can be prepared for
a rescue flight?

My guess is that a "fast turnaround" is going to require at least a few
days or even weeks; Shuttle was originally supposed to have a two-week
turnaround but that's never even remotely worked in practice.

I believe the fastest turn-around of an orbiter was between STS-83 and
STS-94

landed - April 8th 1997
launched - July 1st 1997


Would a "new generation" Shuttle have a shorter turnaround, if new or
improved systems were available? Probably, but it depends on the
individual systems--particularly the thermal protection system has been
very sensitive and requiring detailed inspection and maintenence. A
different type of technology seems essential for the TPS, perhaps a
whole new Shuttle design fundamentally different from the existing
system.

If I were building a Mark II shuttle, I'd focus on the engines, OMS/APU/RCS
subsystems and the toilet. (Folks left out the toilet!)

The TPS I'd work on improving, but at this point for something that large,
not sure how much you could improve it.

It's far better than it was, that's for sure.


There's no lack of proposed reusable spacecraft/launch systems, but I'm
guessing a couple more generations of engineering and development will
be required to get turnarounds remotely similar to routine airline
operations.

It'll happen when there's a need for it.

--Damon



--
Greg Moore
Ask me about lily, an RPI based CMC.

"Greg D. Moore \(Strider\)" wrote in
:


Would a "new generation" Shuttle have a shorter turnaround, if new or
improved systems were available? Probably, but it depends on the
individual systems--particularly the thermal protection system has
been very sensitive and requiring detailed inspection and
maintenence. A different type of technology seems essential for the
TPS, perhaps a whole new Shuttle design fundamentally different from
the existing system.

If I were building a Mark II shuttle, I'd focus on the engines,
OMS/APU/RCS subsystems and the toilet. (Folks left out the toilet!)

The TPS I'd work on improving, but at this point for something that
large, not sure how much you could improve it.

It's far better than it was, that's for sure.

While the ideal Shuttle replacement has usually been conceived as
SSTO, that's too expensive to develop--even now I don't think the
technology is available at even unreasonable cost. But a fully
reusable TSTO ought to be relatively easy, and most of it off the
shelf.

My preferred idea for a "new Shuttle" would be along the lines of two
essentially identical airframes; one a kero-lox booster with minimal
TPS if any at all, and the other a hydrogen-lox orbiter with metallic
shingles instead of ceramic tiles. They'd launch in tandem and the
booster would return to launch site. No solids and no linear aerospike
engines; conventional RD-180 or RD-191 and SSMEs/RL-10 engines, and
alcohol/LOX/peroxide thrusters. Otherwise it's just a scaled up
X-33-like 'Bimese' concept as has been proposed several times over the
decades.

The booster ought to have fast turnaround, but it'd be cheaper and
thus a stable of two or three boosters per orbiter could be just as
workable.

The orbiter will be the weight sensitive part because it'll have to
be more complex and carry a robust TPS plus a useful payload bay.

The orbiter shouldn't be any larger than needed to support ISS; use
the boosters with an unmanned conventional cylinder tanks to launch
heavier/bulkier payloads. I wouldn't rule out an unmanned orbiter
to haul water/propellants/whatever--that'd save weight and improve
payload.

No hydraulics either; fully electrical systems powered by fuel cells
are mature enough technology. I think everything else in current use
is good enough, or make stuff like the toilet a plug-in module.

This still wouldn't be airline-type operations, but it'd be a lightyear
ahead of current Shuttle systems.

Of course no one's developing such a system; any new launch systems are
conventional derivatives of known technology such as SpaceX is doing
with Falcon and Dragon--because it's probably cheaper to develop.

But I think we're really going to miss Shuttle's capabilities, and that
will eventually drive development of new Shuttle-like systems.

--Damon

"Damon Hill" wrote in message
...
"Greg D. Moore \(Strider\)" wrote in
:


If I were building a Mark II shuttle, I'd focus on the engines,
OMS/APU/RCS subsystems and the toilet. (Folks left out the toilet!)

The TPS I'd work on improving, but at this point for something that
large, not sure how much you could improve it.

It's far better than it was, that's for sure.

While the ideal Shuttle replacement has usually been conceived as
SSTO, that's too expensive to develop--even now I don't think the
technology is available at even unreasonable cost. But a fully
reusable TSTO ought to be relatively easy, and most of it off the
shelf.

Well note above when I was referring to a Mark II shuttle, I meant keeping
the same moldlines.

Simply replace the OV-10x model with a OV-20x model. I still think there's
a lot of merit in that, but that's a different discussion.



My preferred idea for a "new Shuttle" would be along the lines of two
essentially identical airframes; one a kero-lox booster with minimal
TPS if any at all, and the other a hydrogen-lox orbiter with metallic
shingles instead of ceramic tiles. They'd launch in tandem and the
booster would return to launch site. No solids and no linear aerospike
engines; conventional RD-180 or RD-191 and SSMEs/RL-10 engines, and
alcohol/LOX/peroxide thrusters. Otherwise it's just a scaled up
X-33-like 'Bimese' concept as has been proposed several times over the
decades.


I was going to say this sounded like the Bimese concept that's been around
since at least the 70s.

Would you design it to to be VTHL or what?


The booster ought to have fast turnaround, but it'd be cheaper and
thus a stable of two or three boosters per orbiter could be just as
workable.

Don't you mean the other way around? (i.e one booster could turn-around
faster and launch 203 orbiters?)


The orbiter will be the weight sensitive part because it'll have to
be more complex and carry a robust TPS plus a useful payload bay.


I'm not sure how much more complex it really would be. Both would need life
support, landing gear, guidance, etc.

I agree you'd definitely need a more robust TPS though.


The orbiter shouldn't be any larger than needed to support ISS; use
the boosters with an unmanned conventional cylinder tanks to launch
heavier/bulkier payloads. I wouldn't rule out an unmanned orbiter
to haul water/propellants/whatever--that'd save weight and improve
payload.

If you're using COTS, sure. I wouldn't want to see a whole other platform
built just for this.


No hydraulics either; fully electrical systems powered by fuel cells
are mature enough technology. I think everything else in current use
is good enough, or make stuff like the toilet a plug-in module.

Definitely. In fact, I'd really make sure to design for re-usability at a
sacrifice in payload.



This still wouldn't be airline-type operations, but it'd be a lightyear
ahead of current Shuttle systems.

We don't need airline-type operations, yet. I'd settle for SR-71 type
operations where you can sortie on fairly short notice and turn around in a
reasonable amount of time.


Of course no one's developing such a system; any new launch systems are
conventional derivatives of known technology such as SpaceX is doing
with Falcon and Dragon--because it's probably cheaper to develop.

But I think we're really going to miss Shuttle's capabilities, and that
will eventually drive development of new Shuttle-like systems.

Despite what some have claimed, I think the loss of MPLM capability will
hurt. One of the great strengths of the ISS design was that you could
easily carry large items up AND down easily.



--Damon



--
Greg Moore
Ask me about lily, an RPI based CMC.

"Damon Hill" wrote in message
...
My preferred idea for a "new Shuttle" would be along the lines of two
essentially identical airframes; one a kero-lox booster with minimal
TPS if any at all, and the other a hydrogen-lox orbiter with metallic
shingles instead of ceramic tiles. They'd launch in tandem and the
booster would return to launch site. No solids and no linear aerospike
engines; conventional RD-180 or RD-191 and SSMEs/RL-10 engines, and
alcohol/LOX/peroxide thrusters. Otherwise it's just a scaled up
X-33-like 'Bimese' concept as has been proposed several times over the
decades.

A friend at work had a co-worker at another job that used to say, "Things
that are different, just aren't the same." That applies here. Your two
stages may *look* the same, but they will end up being vastly different
because of the different flight regimes, fuels, engines, and etc. Beyond
that, there is the temptation for engineers to "tweak" the stages to be even
more different than they absolutely need to be, most likely to save weight
since traditional aerospace engineers get caught up in thinking that
minimizing weight (or minimizing the dry mass to payload ratio) is THE
variable to optimize in a design.

In the end, you'll have to pay to develop two completely different reusable
stages that only appear to be the same to the untrained eye.

Of course no one's developing such a system; any new launch systems are
conventional derivatives of known technology such as SpaceX is doing
with Falcon and Dragon--because it's probably cheaper to develop.

And they're proving that there is room for improvement even for expendable
designs.

But I think we're really going to miss Shuttle's capabilities, and that
will eventually drive development of new Shuttle-like systems.

Perhaps, or we'll adapt and start placing much of the shuttle's capabilities
elsewhere, like on a space station (e.g. the ISS has *two* airlocks, the
SSRMS, and etc.), or perhaps even a manned reusable tug once we finally get
off our behinds and develop in orbit refueling.

Barring ISS, reuse of hardware that's already been launched is something
NASA has not done enough of. Spacelab is a perfect example of this. That
hardware supported a mission of less than two weeks followed by months or
years of sitting on the ground. While that's hardly the best use of such
hardware, it was the only use that the shuttle would support due to its
infrequent flights.

Jeff
--
beb - To paraphrase Stephen Colbert, reality has an anti-Ares I bias.

"Greg D. Moore (Strider)" wrote in message
m...
Well note above when I was referring to a Mark II shuttle, I meant keeping
the same moldlines.

Simply replace the OV-10x model with a OV-20x model. I still think
there's a lot of merit in that, but that's a different discussion.

A design that retains the shuttle's flaw of side mounting on an ET which
sheds foam during liftoff is a design bug which would not be easy to correct
and still keep the same moldlines.

Despite what some have claimed, I think the loss of MPLM capability will
hurt. One of the great strengths of the ISS design was that you could
easily carry large items up AND down easily.

I'd like to note that to date, much more "useful" mass has gone up to ISS
than has come down. The upmass capability can be partially replaced by ATV,
HTV, and various COTS proposals. Hopefully COTS proposals like the Space-X
Dragon will (eventually) replace some of the downmass capability.

Jeff
--
beb - To paraphrase Stephen Colbert, reality has an anti-Ares I bias.

"Jeff Findley" wrote in message
...


Barring ISS, reuse of hardware that's already been launched is something
NASA has not done enough of. Spacelab is a perfect example of this.
That hardware supported a mission of less than two weeks followed by
months or years of sitting on the ground. While that's hardly the best
use of such hardware, it was the only use that the shuttle would support
due to its infrequent flights.


I've always wondered why they didn't fly Spacelab missions more often.

Granted, flight rate was a factor, but given the workflow, I'd argue in many
years adding a flight or two wasn't entirely impossible. I've always
wondered how much the budget purely drove the flight rate. i.e. what would
have happened with another billion a year.

Today the point is sort of moot with only 3 shuttles.


Jeff
--
beb - To paraphrase Stephen Colbert, reality has an anti-Ares I bias.





--
Greg Moore
Ask me about lily, an RPI based CMC.