Transterrestrial Musings

Comments

I know SRB is the Solid Rocket Booster. What's an ET?

Posted by Jerry at July 29, 2005 05:48 AM

External Tank

Posted by at July 29, 2005 06:16 AM

The thrust of the right SRB was down by 100,000 lbf by the time of the breakup, due to decreased internal pressure. So perhaps a lateral force of (say) 50,000 lbf at that point would be a reasonable guess (the hole not being a very effective nozzle, and the burn rate of the fuel being reduced a bit due to the lower internal pressure).

The lateral force would have grown later as the hole eroded and enlarged, and the SRB might have failed catastrophically before burnout if it had not been deliberately destroyed by the RSO at ~110 seconds.

Posted by Paul Dietz at July 29, 2005 06:42 AM

Spaceflightnow.com has a pretty detailed timeline of the Challenger disaster launch up till breakup.

T+72.284

The two solid rocket boosters change position relative to each other, indicating the right-side booster apparently has pulled away from one of the struts that connected its aft end to the external fuel tank. TV tracking camera: A large ball of orange fire appears higher on the other side of main fuel tank, closer to Challenger's cabin, and grows rapidly.

T+72.478

A "major high rate actuator command" is recorded from one of the boosters, indicating extreme nozzle motions.

T+72.497

The nozzles of the three liquid-fueled main engines begin moving at high rates: Five degrees per second.

T+72.525

Data shows a sudden lateral acceleration to the right jolts the shuttle with a force of .227 times normal gravity. This may have been felt by the crew.

Prior to the booster beginning to seperate prematurely there were several recorded engine nozzle movements and even elevon movements to dampen out a slight pitching created by the leak. It could be hard to say exactly how much compensation was being induced by the leak; however, because on this particular day there was wind shear to contend with.

Posted by Josh Reiter at July 29, 2005 07:35 AM

Come on, Rand, you know that the boosters crossed in the fireball. M****n said so.

Posted by Rick C at July 29, 2005 07:36 AM

An SRB + J2 launch system safety study.

I have read elsewhere that by adjusting the fuel grain in the solids the possibility of an explosive catastrophic failure can be eliminated. The fuel will burn but it cannot explode.

An SRB CEV abort would start by blowing holes in the SRB to terminate upwards thrust before firing the escape tower to pull the capsule free. Thus the SRB is not "chasing after" the CEV crew capule.

= = =

All of this underlines the genuis of the t/Space system. Airlaunch means NO zero altitude aborts and airlaunch at 30,000 feet allows simple pressure fed engines saving weight and expense.

Finding a way to fund t/Space ASAP might be the best short term bet for the alt-spacers.

Posted by Bill White at July 29, 2005 08:05 AM

Of course any future shuttle derived HLV would be using current design SRB's and not ones of the design that destroyed Challenger. AFAIK there have been no problems with the current SRB's that would approach any significant fraction of what was going on with the early SRBs.

And I agree with Mr. White on the t/Space proposal, it makes perfect sense for launching crews. The only area I have pause with is the reversable sling seats, I'm not 100 percent sold on that idea yet.

Posted by Cecil Trotter at July 29, 2005 08:20 AM

The safety study is intriguing, but I need to ask if it was officially delivered. The report is dated 1 Apr 2005, but states in an early conclusion (1.5 on page 20) that the system meets the needs of the astronaut memo of 4 May 2005. Also, there are a series of "? pressure" entries that look like un-updated links.

Posted by Tom at July 29, 2005 09:17 AM

Tom, I found that safety study while reading the space.com message board.

I wonder if SAIC would respond to inquiries.

Posted by Bill White at July 29, 2005 09:38 AM

"that the system meets the needs of the astronaut memo of 4 May 2005."

I will bet that is a typo for 4 may 2004.

Posted by Mike Puckett at July 29, 2005 09:55 AM

While th hole wasn't an effective nozzle, ISTR seeing a picture of that section of the SRB being recovered - the hole had grown to nearly a meter in diameter by the time the SRB was destroyed by range safety.

Posted by Derek L. at July 29, 2005 10:07 AM

Why not paint the ET, like was done for the first two missions back in 1981? Sure, it's a little extra weight, but a well-chosen paint might hold up a little better than the foam alone.

Posted by JohnAnnArbor at July 29, 2005 10:59 AM

Eventually, another idea may be to stop putting foam on it at all. Once the payload has moved to the top, the vulnerability falls on the SRBs. Older boosters weren't covered in foam, they just shook ice that formed on the sides off at ignition. Of course, the "old rockets" didn't have critical components attached to their sides like the ET has its SRBs.

Paint weight may make delivery of some station components difficult or impossible. The ultra lightweight tank was developed to get the mass down.

Posted by Tom at July 29, 2005 11:35 AM

Tom: some insulation is necessary to prevent unacceptable heating loads, particularly on the LH2 tank. A bare, uninsulated LH2 tank would condense air, causing a large and continuing input of the released latent heat. LOX dripping off the tank (remember, O2 boils at 90 K, N2 at 77K) could also be hazardous if it soaked into combustible materials on the ground beneath the vehicle.

Posted by Paul Dietz at July 29, 2005 11:58 AM

Why is there foam on the ET at all? Forgive my ignorance but I don't understand what the purpose of the foam really is.

Posted by CJ at July 29, 2005 12:41 PM

Ha....posted while the page updated. Thanks Paul.

Posted by CJ at July 29, 2005 12:43 PM

This is going to sound naive...what stops them from putting the insulation on the inside of the tank? The ET looks like a couple of tanks within a protective outer shell.

Posted by Mark at July 29, 2005 12:46 PM

Of course, the "old rockets" didn't have critical components attached to their sides like the ET has its SRBs.

I point you to the vernier and the sustainer housings on the early Atlas models. I alsopoint you towards the fairings over the outboard engines of the Saturn V first stage. Further back we have the fins on the Redstone....

Shuttle isn't the first time NASA has had to deal with ice/debris shedding causing potential problems. What is unique to the Shuttle is the extreme vulnerability of the craft and the length of the period in which debris is a problem.

Oh, and before I forget - Consider Skylab, where the booster was damaged by debris from the payload.

Posted by Derek L. at July 29, 2005 01:07 PM

"what stops them from putting the insulation on the inside of the tank?"

Because with a higher temperature structure the tank would be in danger of rupturing when fully fueled.

The aluminum alloy it's made from is much stonger at cryogenic temperatures than it is at room temperature. And the tank structural margins are low, a safety factor of ~1.25 if I remember...

Posted by Kevin Parkin at July 29, 2005 01:21 PM

Especially now that the fleet is grounded once more with Discovery
still in orbit; it is VITAL that ALL space enthusiasts write, fax,
call, and email their political representatives and their local and
mainstream media. In your own words you need to point out that Area
51 HAS superior technological aerodynamic machines than ANY other
place on the planet. Don't THEY have something better and safer than
the shuttle for getting into orbit? Why doesn't the media and
political and defense leadership honestly address this question?
Should Astronauts continue to be sacrificed for some false sense of
national security when better access to space exists at Area 51 and
the Utah Facilities and other bases around the globe in the deepblack
projects of DARPA? America has no 'space fleet' right now capable of
flying by mainstream standards and we are once more dependant on the
Russians for rides to space. Soon we'll have to include the Chinese
as well.

From the DisclsoureProject.org we KNOW from Astronauts, Military,
Governmental FAA, FBI, DMA, CIA, DARPA, Pentagon personnel from
AirForce, Marines, Navy, Army, CoastGuard and even civilian persons
of note have made sworn testimony they would like to get before
congress that America already HAS and is USING anti-gravity
propulsion technology to go from ground to orbit and beyond easily,
safely and routinely. One of the main reasons for secrecy is not
only the technology of how it is done, but especially the fact that
humanity is not alone in the Solar System, much less the Universe
itself.

This denial and refusal to LOOK with a SERIOUS intent on
declassifying SOME of the Area 51 aerospace capabilities will
continue to cost Astronaut lives, billions in wasted tax dollars, and
a lost of the American vision and dream. We will not shape the
political and economics of the coming Solar System dynamics.

You can help change this by writing, calling, faxing, emailing the
prattling politicians, the babbling beaurocrats, the mindless media
minions both local and national. The time for Area 51 to come out of
the closet is NOW !

http://www.enterprisemission.com/help.htm

It is time to stop throwing dice with Astronaut lives in a game that
is rigged against them to begin with. This is like not providing
proper armor to our troops in the first years of this Iraq war. We
are not providing the BEST aerospace capabilities to our space
effort. It really IS that simple. I thank creation people like
Richard are holding NASA's feet to the fire. We need to also act in
concert and make our voices heard.

Say what you mean and mean what you say.

Don't make promises and policies you don't intend to keep and to keep
the policies and promises you do make.

ACTIONS speak louder than words.
ACTIONS are PROOF of intent.
ACTIONS are the final judgement of character.

It REALLY is that simple.

Bob... :D
http://www.commonsensecentral.com

Posted by Robert Williams at July 29, 2005 05:51 PM

I hope that somebody takes notice of this post after all of the quackery that was spewed in the previous screed, but here goes:

I wonder if it's possible to replace the foam PAL ramp with a piece of heated aluminum that serves the same purpose. If anybody has heard this discussed within the industry, please let us know about it.

The PAL ramp and the previous problem, the bipod ramp, had one thing in common: they were manually shaped. Tiny bubbles in the foam expanded as atmospheric pressure decreased, causing big chunks to separate.

The bipod solution was simple: remove the bipod foam and heat the exposed area. Fixing the PAL ramp cannot be done the same way, because the piece is vital to the shuttle's aerodynamics.

What we need is something that will serve the same aerodynamic function while remaining attached to the ET. An aluminum structure of the same form factor should do the trick. Heaters will also be necessary to prevent ice formation. Of course, a change like this will probably take months to implement while NASA ensures that it is structurally and aerodynamically sound.

In short, I don't think it was a mistake to launch Discovery when we did. It was a TEST FLIGHT, and as such it evaluated the modified ET. We found out that certain fixes worked, while the PAL ramp was a neglected problem. Let's fix the immediate problem with the PAL ramp, finish construction of the albatross-like ISS, and retire the weary space shuttle.

Posted by Impossible Scissors at July 29, 2005 06:59 PM

Or make it out of fiberglass or carbon fiber.

Posted by Mike Puckett at July 29, 2005 07:06 PM

I think Griffin's point is that he's essentially already got a heavy lift vehicle if you subtract all the parasitic weight that the orbiter represents. That's not to say it's the best solution (probably near the bottom as solutions go.)

I always thought of it in terms of reusing components that we've already build, like the main engines. They are described as the most effecient ever built (F1's being the most powerful) but apparently they are a costly maintenance nightmare... so what's the point of reusing them?

The DC-X sort of proved the concept that off the shelf components put together in ingenious ways could produce an economical vehicle. What NASA spent on foam research in the last two year could have built a real SSTO by some commercial venture with a good vision.

I like Griffin, but wonder if he's putting more life into an agency that aught to die a good death so private industry can fill in the gap...

It bothersome that so much commercial traffic is going to foreign companies. Something has to happen... I'm still optimistic about Americans (private enterprise) being up to the challenge (eventually/soon?)

Posted by ken anthony at July 29, 2005 09:33 PM

In response to Ken, I have to say that the reason SSTO hasn't been done is because SSTO can't be done with the current generation of materials technology (unless you want to sacrifice any useful payload capability and work like the dickens to avoid weight growth.) Multi-stage vehicles will always have more capability than SSTO's. That's why a truly reusable TSTO is the way to go.

IMHO, the most important achievements of DC-X were the lean operations and rapid turnarounds. At the same time, the vehicle's performance was too limited to demonstrate anything that was truly groundbreaking (new heat shield concepts, the rotation maneuver, etc.)

I predict that expendible launchers will be around for decades to come, although some degree of reusability will be built in until we eventually get a true RLV.

So we'll use expendible rockets to get back to the moon, and Mike Griffin has prettymuch committed us to shuttle-derived heavy lift. Unless that decision is quickly overturned, we have no better choice than to fix the shuttle we have, to use as a basis for the heavy-lifter.

Will NASA implement the aluminum PAL ramp, or will they fix it some other way?

Posted by Impossible Scissors at July 29, 2005 09:55 PM

Jeez. I watched Stargate SG-1 earlier tonight, but I know it's just a TV show.

In the event of an emergency, why don't we just ask the Asgard to beam the astronauts out of Shuttle!

Posted by Astrosmith at July 30, 2005 12:05 AM

Anybody else see the current SG-1 storyline as a slam on Islam?

Posted by Mike Puckett at July 30, 2005 08:18 AM

Mike: Yep, sure do.

Hallowed are the Ori.

You will see the light of the Ori,
or you will be destroyed...

infidel!

Posted by Astrosmith at July 30, 2005 08:25 AM

Which makes me wonder...

Rand, have you ever run into good ol' Richard Hoagland?

Posted by Astrosmith at July 30, 2005 08:41 AM

Area 51 technology is obtainable upon paying a $1,000,000,000 bank check royalty to me personally. Contact me off-line for details.

Posted by philw Area 51 commondant at July 30, 2005 12:03 PM

This entry is an excellent statement of NASA's good works and their failures.

I watched the pre-bed broadcast from the ISS on the 31st. I just wish that Congress, NASA, and the communication media would listen to the astronauts instead of to the Weeping Whilamenas who are more worried about the astronauts' families. The astronauts want to fly, and, in my opinion, they are very satisfied with everything.

Posted by Bernard W Joseph at July 31, 2005 05:36 PM

Have you fellows seen this? It is disheartening:

http://www.spaceref.com/news/viewnews.html?id=1055

"NASA's New CEV Launcher to Maximize Use of Space Shuttle Components

Frank Sietzen, Jr. and Keith L. Cowing
Sunday, July 31, 2005

The decision on what new launch vehicles NASA plans to use in the coming decades is rapidly coming into focus. In some ways these launchers will be new - yet they will also look very familiar using hardware and concepts that have long and well-established flight histories.

Analysts have reviewed a wide variety of launch vehicle options for both manned and cargo-only versions of the NASA Crew Exploration Vehicle (CEV) and have settled for an all-solid booster configuration, according to sources close to NASA's Exploration Systems Architecture Study (aka the "60 Day Study")

But a year-long study initiated prior to the change in NASA Administrators and completed this spring gave an extensive review to both uses of a launch vehicle derived from the Space Shuttle's Solid Rocket Booster (SRB) as well as a larger booster design using twin SRB motors flanking a derivative of the shuttle's External Tank (ET), mated with a large liquid upper stage. Studies also looked at growth options from the nation's Evolved Expendable Launch Vehicles (EELV) community.

Internal NASA documents detailing the review, which was completed in late June, were obtained by the authors. A second, related study has reviewed heavy lift options using the same shuttle-derived elements.

...

SRB-derived Booster

Two series of boosters were evaluated derived from the Space Shuttle SRBs. Assumptions made included full recovery of the booster, use of a new retrorocket system, and a new liquid upper stage that would be large enough to inject the CEV into orbit and be restarted multiple times for approach to a lunar fleet, or to approach and depart from the ISS. Both four and five segment motors were studied.

Three upper stage candidates were evaluated. One using the SSME, one using the J2S, and one using the Russian AJ26-60 version of the N-1 launch vehicle's NK-43 upper stage engine. All variants of an SRB booster could lift a 20 metric ton CEV package. But a five-segment motor would be required to launch a larger 30 metric ton. CEV design. Increasing the reference thrust of the SSME to 109% was also studied for the SRB CEV launcher's upper stage. Both SRB designs require extensive launch pad and launch logistics modifications at Kennedy Space Center. For planning, stacking of the motors inside the VAB was assumed, which would require construction of new work platforms there. At the pad, a new mobile launch platform that would be shared with the shuttle-derived heavy lifter was also assumed.

Click on image to enlarge

Among the shortcomings of any SRB-derived launcher was lack of engine out capability. For all of the shuttle-derived manned launcher designs, SSME modifications were needed, the J2S would require technology improvements for updating, and the Russian engines would require new arrangements. ... "

In other words, NASA is considering almost everything, EXCEPT FRESH NEW DESIGNS.

And I suggest that it won't all that cheap or quick to make these "derivative" designs fly. For example, "Both SRB designs require extensive launch pad and launch logistics modifications at Kennedy Space Center. ... At the pad, a new mobile launch platform that would be shared with the shuttle-derived heavy lifter was also assumed."

That's "Billions o' $," plural, with a "B" on the front and an "s" on the end of the word right there, for improvements to ground infrastructure needed to pour the old Soild Rocket Booster wine into a CEV bottle.

-- David Davenport

Posted by David Davenport at August 1, 2005 10:53 AM

How do you know they didn't consider fresh designs? It may be that they considered them, looked at the cost, and concluded they weren't feasible or were too risky.

It certainly won't be 'cheap' to make these derivatives fly, but that doesn't mean a completely clean sheet design wouldn't be even more expensive.

Posted by Paul Dietz at August 1, 2005 11:14 AM

Re: "NASA's New CEV Launcher to Maximize Use of Space Shuttle Components"

Component-based design is the way to go in this situation. If developing a non-chemical launcher is off the table then there's no point in reinventing every spoke in the wheel just for standard rocket propulsion.

For example the cheapest types of satellites are made by changing as little as possible with the design and using the same outdated parts over and over again until, for whatever reason, that part can no longer be obtained. I see no reason for launchers to be any different.

It only makes sense to develop all-new parts when building something substantially new. Neither of the proposed launchers are substantially new devices - they are both chemical rockets, they will both have chemical rocket performance.

Posted by Kevin Parkin at August 1, 2005 01:18 PM

A clean sheet design would also "require extensive launch pad and launch logistics modifications at Kennedy Space Center" with the billions with a "B" and an "S" strawman argument still applying. The last clean sheet design resulted in the Shuttle.

Far from disheartening, the Sietzen/Cowing article above is the best news I've read in quite some time.

Posted by Cecil Trotter at August 1, 2005 01:22 PM

> A clean sheet design would also "require extensive launch pad and
> launch logistics modifications at Kennedy Space Center" with the
> billions with a "B" and an "S" strawman argument still applying.

That'ss heavy on the "B-S." A clean-sheet launcher might take off from an ordinary airport. There's no reason it necessarily needs a launch pad, much less a launch pad that costs billions of dollars.

> Far from disheartening, the Sietzen/Cowing article above is
> the best news I've read in quite some time.

If your goal is to maximize the number of civil servants on the ground required to send one civil servant into orbit.

Posted by at August 1, 2005 02:31 PM

[ How do you know they didn't consider fresh designs? It may be that they considered them, looked at the cost, and concluded they weren't feasible or were too risky. ]

The citation mentions nothing about other, innovative designs. If Dr. Griffin and other geniuses at the Planetary Society considered fresh manned vehicle launch designs and rejected them for good reasons, why don't they state those good reasons?

Note: I am primarily concerned with their proposed manned laucnch vehicle, not the heavy cargo launcher.

[It only makes sense to develop all-new parts when building something substantially new.]

I'll confess, I have hoped that someday NASA would build a substantially new launch system.

[ Neither of the proposed launchers are substantially new devices - they are both chemical rockets, they will both have chemical rocket performance. ]

They are both chemical rockets? So parts is parts ... potato chips, computer chips, what the hell difference does it make? All "chemical rockets" are pretty much the same, right? In that case, why not use a good ole liquid fuel first stage instead of that Thiokal solid booster.
Want a golden oldie? In that case, why not build Saturn V stacks again? No Saturn V first stage ever killed people, unlike the Thiokal SRB's.

What do you mean by this "chemical rockets" sneer, anyway? Are you one of the space elevator or anti-gravity enthusiasts? Do you assign scramjets to the infra dig "chemical rockets" category? If so, do you think scramjet R&D is a waste?

[ A clean sheet design would also "require extensive launch pad and launch logistics modifications at Kennedy Space Center" with the billions with a "B" and an "S" strawman argument still applying. ]

But a two-stage horizontal take off, horizontal landing aerospace vehicle might not. Once again, I am thinking in terms of a spaceplane that could take no more than four humans at a time to LEO. A big cargo lifter is another matter.

Furthermore, some of the goals of the X-33 program seem to have been sucked into the memory black hole. These goals included:

"...

* demonstrate ability to perform 7-day turnarounds between three consecutive flights (a turnaround is the amount of time required from a takeoff and flight until the vehicle is serviced, refueled, and ready to fly again)

* demonstrate ability to perform a 2-day turnaround between two consecutive flights

* demonstrate that a maximum of 50 personnel performing hands-on vehicle operations, maintenance, and refueling can successfully accomplish flight readiness for two flights.

...'

http://www.fas.org/spp/guide/usa/launch/x-33.htm

In contrast, this capsule on an H2/O2 second stage atop an SRB will be taller and more tipsy than the side-by-side Shuttle set while on the ground. It'll probably take about seven days to crawl the thing from the Vehicle Assembly Building to the launch pad.

[ The last clean sheet design resulted in the Shuttle. ]

Following that logic, no clean sheet manned space launch systems should ever again be designed, including Dr. Griffin's or Planetary Society's Apollo-capsule on an SRB!

Dr. Griffin's design is a rhetorical trick. There's a lot of rhetoric about this proposal using trusty, proven compnents from the Shuttle system.

Actually, howsomeever, the design calls for a second stage using a single SSME or else maybe an RS68 H2/O2 engine and propellant tanks "derived" from from the Shuttle's External Tank. That second stage is really a new design that does not exist yet, sitting beneath a capsule whose detailed design does not exist yet. The first stage for this beauty will probably be a five segment SRB instead of the existing four segment Soild Rocket Booster. A five segment SRB has yet to be designed and built.

[ If your goal is to maximize the number of civil servants on the ground required to send one civil servant into orbit. ]

That seems to be the real agenda here, along with goodies for Thiokal.

Posted by David Davenport at August 1, 2005 03:51 PM

"How do you know they didn't consider fresh designs?"

They didn't. If I'm wrong, Keith Cowing evidently has the report can delight in correcting me.

In the past NASA has not sufficiently nurtured alternatives to chemical launch; such as tethers, guns, directed energy launch etc. I know that over the past 40 years much money has gone into airbreathing propulsion, albeit in fits and spurts, but what I'm talking about is the other alternatives that have gotten only cocktail money, if that.

Momentum exchange tethers for example are quite possible to the best of our knowledge. Had the NASA of the 1980s decided that the NASA of the 00's should have the option of tether launch, then I wouldn't have to qualify its description with "to the best of our knowledge" - the unknowns would have been eliminated one by one and tethers could have been a newly credible alternative for Griffin's study.

As it stands NASA has few options: The small but important investments in alternatives were not made and 40 years after Apollo was started NASA has been forced to start again with all the same options that Apollo had, less one (nuclear launch).

The reason that's a problem is that NASA can afford to begin but not sustain the Exploration Initative with conventional rockets. And now the Shuttle debacle has forced Griffin into again choosing the chemical option for the next few decades -- even though it cannot meet his goals.

I realize that many are hoping commercial forces can lower the chemical launch cost enough to keep the dream alive, and I too hope they're right. But NASA is an agency tasked with making the investments industry will not, and only commerce can create commercial launchers. NASA should be developing the non-chemical launch alternatives industry will not; lack of foresight, bad policy and always shopping at the same two stores has now forced it to ignore the commercial options and reassemble space shuttle parts to recreate a heavy launch capability we scrapped 30 years ago.

In suppose the question now is will the NASA of the 00's make the same investment mistake as the NASA of the 1980s?

Posted by Kevin Parkin at August 1, 2005 06:15 PM

[ Momentum exchange tethers for example are quite possible to the best of our knowledge. Had the NASA of the 1980s decided that the NASA of the 00's should have the option of tether launch, then I wouldn't have to qualify its description with "to the best of our knowledge" - ]

How would one place in higher Earth orbit a large tether with mucho momentum to exchange without big, sophisticated "chemical" rocket launch vehicles to get the tether up there in position in the first place?

The same goes for space elevators.

Tether launch? File that under space elevators.

Posted by David Davenport at August 1, 2005 07:52 PM

*rolls eyes*

http://www.tethers.com/papers/MXERJPC2003Paper.pdf

Posted by Kevin Parkin at August 1, 2005 08:46 PM

"That'ss heavy on the "B-S." A clean-sheet launcher might take off from an ordinary airport."

And Scotty might just beam us up into LEO, but I ain't holding my breath.

Posted by Cecil Trotter at August 2, 2005 10:33 AM

"Furthermore, some of the goals of the X-33 program seem to have been sucked into the memory black hole. These goals included:

"...

* demonstrate ability to perform a 2-day turnaround between two consecutive flights

* demonstrate that a maximum of 50 personnel performing hands-on vehicle operations, maintenance, and refueling can successfully accomplish flight readiness for two flights."

Those were once stated goals for the space shuttle too, but we know how that turned out.

Posted by Cecil Trotter at August 2, 2005 10:36 AM

Cecil, is it your position that because Shuttle and X-33 were failures, that fast turnaround and low-cost operations are somehow therefore unachievable goals?

If so, could you provide some logic in support of that? It's like saying that because the Convair 880 was a commercial failure that commercially viable aircraft weren't possible in the late 1950s.

Posted by Rand Simberg at August 2, 2005 11:32 AM

[ If so, could you provide some logic in support of that? It's like saying that because the Convair 880 was a commercial failure that commercially viable aircraft weren't possible in the late 1950s. ]

Is it possible that Cecil is the kind of Brit who has never gotten over the Comet airliner?

Posted by David Davenport at August 2, 2005 04:04 PM

Simberg: "fast turnaround and low-cost operations are somehow therefore unachievable goals?"

For a large "do everything" vehicle like the shuttle I think fast turnaround/low cost ops are presently beyond our technical ability. I do think those goals could likly be acheieved with a smaller, simpler crew transport only vehicle.

Davenport: "Is it possible that Cecil is the kind of Brit"

Why do you assume I'm British? Not that being British would be a bad thing....

Posted by Cecil Trotter at August 3, 2005 05:00 AM

For a large "do everything" vehicle like the shuttle I think fast turnaround/low cost ops are presently beyond our technical ability.

That's interesting, I guess, but I fail to see the relevance, since I never said anything about needing a "large, do-everything vehicle." That was one of the mistakes of the Shuttle.

I do think those goals could likly be acheieved with a smaller, simpler crew transport only vehicle.

Why "crew transport only"? Passenger air transports can carry cargo. Whay can't space transports?

Such strangely blinkered thinking.

Posted by Rand Simberg at August 3, 2005 07:09 AM

Well Rand I didn't take you to be one for nit picking and re-parsing of words. No you did not state that you were an advocate of a “large, do everything vehicle” and I never said you were. You questioned me as to whether or not I thought fast turn around and low cost vehicles were achievable goals, in my answer I sited two different types of vehicles and stated that I thought such criteria may be achievable with one and not the other. And I fail to see how you “fail to see the relevance” when you yourself point out the relevance when stating, “That was one of the mistakes of the Shuttle”.

As for my use of the term “crew transport only” there again I was using that only as an example of a vehicle that could possibly be built to meet the goals of fast turn around and low cost, I did not intend to strictly rule out the possibility that a vehicle built to transport crews and “some” cargo might also meet the criteria. Somewhere between the extreme of a “large do everything” and a smaller simpler crew only vehicle is the answer, the “perfect balance” if you will. (Oh, don’t take my use of “perfect” too literally). What that answer is exactly, I don’t know.

Posted by Cecil Trotter at August 3, 2005 08:02 AM

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