Author Topic: Orbital to offer Orion LAS to others? (Read 10783 times)

Rabidpanda · « **Reply #20 on:** 02/21/2010 06:52 am »

Quote from: docmordrid on 02/20/2010 11:05 pm

You mean this? I also have the PDF it came from.

PDF link.....

The LAS/OMS in their picture looks way too small. Maybe it's just the engine and the propellants are stored in the capsule. The capsule itself looks kind of stubby, not the most aerodynamic thing to have on top of a rocket. I wish they had more info in the PDF, all it seems to have are some concept sketches and remarks on how great Atlas V is for crewed launches.

Jim · « **Reply #21 on:** 02/21/2010 09:53 am »

It was one of the OSP designs.

Comga · « **Reply #22 on:** 02/21/2010 04:52 pm »

Quote from: Jim on 02/21/2010 09:53 am

It was one of the OSP designs.

Do you have a link to more information on that proposed design?

That LAS/OMS does look disproportionately small.

(Yes, docmordrid, that image is from the document I had in mind. I have the PDF somewhere inaccessible at the moment. )

docmordrid · « **Reply #23 on:** 02/21/2010 05:15 pm »

Found this more detailed image in a Defence Talk article from 2003. Cut this out of a pic of 4 OSP proposals. Might clarify things a bit.

Comga · « **Reply #24 on:** 02/21/2010 05:54 pm »

The system in this image is quite different from the one behind the LM capsule.

To the point of this topic, if the units behind two versions of one capsule are so different, the modifications of Orbital's Orion LAS for a completely different spacecraft would be extensive, to day the least.

Ben the Space Brit · « **Reply #25 on:** 02/21/2010 07:27 pm »

IIRC, that crew taxi was one of the options ULA mentioned in their skit at the A-Com hearings. I might be wrong, but the use of the term 'passenger' suggests it is a fully remote/computer-controlled vehicle like Dragon was originally intended to be.

docmordrid · « **Reply #26 on:** 02/21/2010 10:45 pm »

Found another image in my collection. Early and not much, but here it is...

Comga · « **Reply #27 on:** 02/22/2010 02:42 am »

Although it is OT, can anyone speculate on how such a system would work? All those lobes and the very small nozzle? (There even seems to be room for a larger nozzle in the adapter to the second stage.) I have a guess, but it's way out of my field of engineering.

Lars_J · « **Reply #28 on:** 02/22/2010 02:49 am »

That does not look like a LAS... Just a tiny de-orbit module. (Like Mercury)

docmordrid · « **Reply #29 on:** 02/22/2010 03:41 am »

And yet it looks much like what's labeled as an Abort/OMS in Lockmart's PDF. Small, lobed etc.

I could see some lobes being tanks and others thrusters, but I agree the main nozzle looks small. Still, nozzle aside, are those lobes big enough to be tanks and thrusters? How about the core being large enough for an adequate thrust chamber?

IMO the image I cut out of the OSP pic looks more adequate to the task.

Ben the Space Brit · « **Reply #30 on:** 02/22/2010 11:03 am »

Quote from: Lars_J on 02/22/2010 02:49 am

That does not look like a LAS... Just a tiny de-orbit module. (Like Mercury)

A lot depends on the thrust of the motor. If it is high enough thrust (and lsp), then there is no reason why it could not theoretically do both jobs. Would a H2O2 monopropellent be sufficient?

I suspect that the RCS on this vehicle would be in the main module, as with Dragon. The basic desing philosophy appears to be maximum reusibility, unlike the Gemini/Apollo model where a major part of the spacecraft is disposed of before re-entry.

Comga · « **Reply #31 on:** 02/23/2010 03:25 am »

OK Here is my guess with little to back it up:

Could each of the lobes be a separate solid motor, with all eight feeding a single plenum, nozzle, and bell? In the case of an abort, all eight fire, generating maximum thrust. If an abort is not called, they are fired singly or in pairs for orbital insertion and deorbit, with some perhaps discarded unfired after the deobit burn in a nominal mission?

It is not clear how they would keep a lit motor from igniting other motors.

They might have to do something like the adaptive coast of the Taurus II to get a more precise orbit injection with an unstoppable burn of a solid motor charge.

I have no idea how the differing burn rates would affect pressure, thrust, and Isp. Anyone out there with better guesses or some real knowledge? (Jim: Tell me how this is more complex and less reliable.)

And almost on topic, could Orbital build a similar architecture with some of the Orion LAS technology? Imagine using the valve system for the steering component on the abort motor itself. In an abort condition all of the side-facing valves remain closed, maximizing thrust, except for brief steering bursts. In a jettison or orbital insertion condition, most of the valves stay open, minimizing or just greatly reducing the forward thrust.

If the valves fail in the initial shut positions, they would get either an unsteered abort or a really, really fast jettison.

HMXHMX · « **Reply #32 on:** 02/23/2010 04:08 am »

Speculation has its place, but have you all considered that this may just be an artist's sketch with no engineering to back it up? That happens all the time.

Sometimes a cigar is just a smoke...

Comga · « **Reply #33 on:** 02/23/2010 05:15 am »

I did think of that, but it seems to be too specific and odd. They wouldn't write the whole article, complete with a discussion of black zones and abort modes, without a concept for LAS whose performance they could evaluate. It would seem to be some whole concept, and although it doesn't have to be a workable one or the optimal one, these are smart professionals. I view this as a chance to learn what they are thinking by examining their illustrations.

Of course, the basic subject here is speculation. Unless Orbital announces a sale, or someone finds out about a discussion between Orbital and SpaceX or other potential spacecraft vendor, there are no factual answers.