Author Topic: Manned spacecraft with integral upper stages  (Read 6493 times)

Offline tnphysics

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Manned spacecraft with integral upper stages
« on: 12/05/2012 01:01 am »
The article http://selenianboondocks.com/2008/09/orbital-access-methodologies-part-vi-air-launched-glideforward-tsto/ brought up the concept of integrating the reusable upper stage and the manned spacecraft payload.

I can think of several advantages to this approach:

- Several systems do not need duplication
  -GN&C
  -TPS
  -RCS

-Upper stage engine doubles as powerful OMS

-Because the "payload" has such a high delta-V (probably from a single RL-10 IMO), only a single stage vehicle is needed to propel the vehicle to a trajectory from which it can boost itself to orbit. In other words, THE SPACECRAFT IS THE UPPER STAGE-which I would expect to be a significant savings in cost compared to the standard approach owing to the no-longer-duplicated systems mentioned above.

One difficulty that I can foresee is that of abort, as the fueled spacecraft is too heavy for an LAS to boost it, and having internal separation is complex. My proposed solution would be to replace the LAS with ejection seats based on those on the SR-71 aircraft, Gemini spacecraft, and Soviet Buran orbiter.

Offline RocketmanUS

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Re: Manned spacecraft with integral upper stages
« Reply #1 on: 12/05/2012 01:15 am »
ACES/Orion

Use a pusher to separate the CM from the rest for an escape system.
Engines ( high thrust ) on the sides with hypergolic propellents ( each with their own propellents ). Possible escape engines drop of when almost in orbit.

The ACES would be the US for the launch vehicle and the in space propulsion and part of the SM. For BLEO it could refuel by tanker or depot. Round trip to EML1/2 or LLO. If not enough delta v for LLO round trip then tanker or depot for needed return or longer stay in LLO.

Possible to refuel at EML1/2 depot to use as a rescue capsule for crew beyond Lunar orbit ( returning NEA, Mars crew were vehicle can not return to EML1/2 for same reason ).

Offline tnphysics

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Re: Manned spacecraft with integral upper stages
« Reply #2 on: 12/05/2012 01:46 am »
I was thinking more of a reusable US (Falcon 9?) with crew compartment in the same stage, with the whole stage having a single TPS.

Offline RocketmanUS

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Re: Manned spacecraft with integral upper stages
« Reply #3 on: 12/05/2012 02:02 am »
I was thinking more of a reusable US (Falcon 9?) with crew compartment in the same stage, with the whole stage having a single TPS.
Kistler K-1
That would have been their crewed version of the K-1 US.

Offline Elmar Moelzer

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Re: Manned spacecraft with integral upper stages
« Reply #4 on: 12/05/2012 02:25 am »
Quote
I was thinking more of a reusable US (Falcon 9?) with crew compartment in the same stage, with the whole stage having a single TPS.
We were briefly talking about this over in the SpaceX forum section.
I think it will make sense once they have more routine and know how safe their upper stages will be and how often they can be reused.
Right now, they would have to keep the capsule all the systems and its TPS separate anyway for aborts. Maybe they can get the abort engines powerful enough in the future (or manage to get higher margins to have largers ones on the second stage).
Anyway, so they would need to double the  systems and thus would not gain anything, worse they would probably have more weight to deal with.
Second thing is, I am not sure they know how often they will be able to reuse the second stage and the capsule. If for some reason the capsule could be reused 30 times (just throwing arround numbers here), but the second stage only 20 times, they would potentially waste a lot having through away both in an integrated system after only 20 flights.
This is why I think that it could make sense at some point in the future, but probably is too ambitious for the first generation.

Offline joek

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Re: Manned spacecraft with integral upper stages
« Reply #5 on: 12/05/2012 03:06 am »
I was thinking more of a reusable US (Falcon 9?) with crew compartment in the same stage, with the whole stage having a single TPS.
Kistler K-1
That would have been their crewed version of the K-1 US.
Also what came to mind for me.  Or maybe a variant of Blue Origin's biconic configuration.

Offline 93143

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Re: Manned spacecraft with integral upper stages
« Reply #6 on: 12/05/2012 03:43 am »
Shuttle II.

Offline docmordrid

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Re: Manned spacecraft with integral upper stages
« Reply #7 on: 12/05/2012 07:26 am »
Shuttle II.

[strike]Wings!![/strike]
DM

Offline RanulfC

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Re: Manned spacecraft with integral upper stages
« Reply #8 on: 12/05/2012 07:34 pm »
The problem with ejection seats is that they only work for a very small portion of the flight profile. REALLY small portion.

The "Shuttle-II" comment was less directed at the vehicle having "wings" I think that the "command/passenger" section being a separable/seperate vehicle for abort purposes. :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Elmar Moelzer

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Re: Manned spacecraft with integral upper stages
« Reply #9 on: 12/05/2012 07:39 pm »
The problem with ejection seats is that they only work for a very small portion of the flight profile. REALLY small portion.

The "Shuttle-II" comment was less directed at the vehicle having "wings" I think that the "command/passenger" section being a separable/seperate vehicle for abort purposes. :)

Randy

Ohh yes, I remember reading about that shortly after the Challenger desaster!

Offline RanulfC

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Re: Manned spacecraft with integral upper stages
« Reply #10 on: 12/05/2012 08:35 pm »
The problem with ejection seats is that they only work for a very small portion of the flight profile. REALLY small portion.

The "Shuttle-II" comment was less directed at the vehicle having "wings" I think that the "command/passenger" section being a separable/seperate vehicle for abort purposes. :)

Ohh yes, I remember reading about that shortly after the Challenger desaster!
Yep that's the one. The idea was to turn the cockpit/mid-deck into a seperate reentry vehicle for abort purposes but as I recall (could be wrong, I admit it doesn't happen often but it is possible ;) ) the Orbiter itself had a set of seperation rockets on it for any "other" abort option.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline simonbp

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Re: Manned spacecraft with integral upper stages
« Reply #11 on: 12/05/2012 08:50 pm »
Or, rather than trying to design two separate spacecraft (before and after abort), you use all that propellant in the upper stage to do the abort. This could be done by having a set of very high thrust, low Isp thrusters hooked up to the same feed line as the normal upper stage engine. The low Isp is especially important, as it lets dump all of that prop really fast, while still getting high acceleration and a bit of impulse out it. Then, after the abort burn, you are far from the first stage and aren't having to lug around all that extra propellant.

An integral upper stage would probably use hydrocarbon fuel, just for packing efficiency, and so you could have a configuration like, say, one Merlin Vac for normal thrust and a few RS-88s for abort, deorbit, etc.

Offline 93143

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Re: Manned spacecraft with integral upper stages
« Reply #12 on: 12/06/2012 04:07 am »
There was a popular Shuttle II concept that was essentially a rocketplane (the orbiter) riding piggyback on another rocketplane (the flyback booster).  Basically exactly what the OP is describing, but with wings and an ejectable crew cabin (and a parallel stack configuration).
« Last Edit: 12/06/2012 04:08 am by 93143 »

Offline kkattula

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Re: Manned spacecraft with integral upper stages
« Reply #13 on: 12/06/2012 06:16 am »
The downside is, once in orbit, the spacecraft has to carry around a very large engine and large, almost empty tanks.

A similar concept I like is a reusable flyback booster, possibly VTVL, with a cheap expendable second stage, then a reusable spacecraft with integrated third stage/SM. The spacecraft would provide the final ascent burn and have all the expensive avionics, etc, to control the launch. It could come in crewed and uncrewed cargo carrier versions.


Offline guckyfan

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Re: Manned spacecraft with integral upper stages
« Reply #14 on: 12/06/2012 08:52 am »
A similar concept I like is a reusable flyback booster, possibly VTVL, with a cheap expendable second stage, then a reusable spacecraft with integrated third stage/SM. The spacecraft would provide the final ascent burn and have all the expensive avionics, etc, to control the launch. It could come in crewed and uncrewed cargo carrier versions.

You are describing Falcon with reusable first stage plus Dragon.  :)

The only thing you need to add would be an extended trunk with fuel tanks plus probably one expendable Super Draco with big vacuum nozzle for optimized vacuum ISP.

You could evaluate if the Dragon avionics and RCS can control the second stage. But it would be worth the effort only if there is a need for very many Dragon flights, manned or unmanned.

The expendable second stage would then be just tank plus one Merlin engine. The cost should not be too high if produced in larger numbers.

I don't know what would be involved to modify a first stage Merlin to a second stage one . If it is easy you could convert 9 first stage engines after 9 flights to expendable second stage engines.


Offline john smith 19

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Re: Manned spacecraft with integral upper stages
« Reply #15 on: 12/06/2012 09:36 am »
The article http://selenianboondocks.com/2008/09/orbital-access-methodologies-part-vi-air-launched-glideforward-tsto/ brought up the concept of integrating the reusable upper stage and the manned spacecraft payload.
That sounds like a fairly good description of the Shuttle without the payload bay but incorporating the ET.

I'd say a lot of the same pros and cons apply. My instinct is people should be treated as an optional payload module. You fly crewed install the appropriate module and link its controls into the flight system. Otherwise let the computers do the work.

Keep in mind under normal circumstances Shuttle launches were under full computer control. Aborts would have been different. Likewise the GPC could have flown the whole landing profile. Only the landing gear release was manual.
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Offline tnphysics

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Re: Manned spacecraft with integral upper stages
« Reply #16 on: 12/07/2012 04:13 pm »
I guess the big idea is in the high flight-rate case (enough to justify two US versions) with a reliability good enough that the US engine can do aborts from the first stage.

Ejection seats can work up to Mach 3 or so-good enough for the lowest-level aborts (before/around Max Q).

Offline Rocket Science

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Re: Manned spacecraft with integral upper stages
« Reply #17 on: 12/07/2012 04:21 pm »
The downside is, once in orbit, the spacecraft has to carry around a very large engine and large, almost empty tanks.

A similar concept I like is a reusable flyback booster, possibly VTVL, with a cheap expendable second stage, then a reusable spacecraft with integrated third stage/SM. The spacecraft would provide the final ascent burn and have all the expensive avionics, etc, to control the launch. It could come in crewed and uncrewed cargo carrier versions.


Have a look at this...

http://forum.nasaspaceflight.com/index.php?topic=27477.0
"The laws of physics are unforgiving"
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Offline kkattula

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Re: Manned spacecraft with integral upper stages
« Reply #18 on: 12/08/2012 09:34 am »
A similar concept I like is a reusable flyback booster, possibly VTVL, with a cheap expendable second stage, then a reusable spacecraft with integrated third stage/SM. The spacecraft would provide the final ascent burn and have all the expensive avionics, etc, to control the launch. It could come in crewed and uncrewed cargo carrier versions.

You are describing Falcon with reusable first stage plus Dragon.  :)

Not exactly. THe first stage would provide less delta v than a Falcon's. Mostly straight up and down with only a little sideways velocity at staging, if any. Makes recovery much easier.

Quote
The only thing you need to add would be an extended trunk with fuel tanks plus probably one expendable Super Draco with big vacuum nozzle for optimized vacuum ISP.

I thought the idea was not to expend any of the spacecraft. It's not really integral if you don't bring it back...

Quote
You could evaluate if the Dragon avionics and RCS can control the second stage. But it would be worth the effort only if there is a need for very many Dragon flights, manned or unmanned.

Move the second stage electronics & RCS into the spacecraft.

Quote
The expendable second stage would then be just tank plus one Merlin engine. The cost should not be too high if produced in larger numbers.

That's the idea. Keep it as simple as possible.  Maybe even encapsulate it inside the first stage, so it needn't be aerodynamic.

Quote
I don't know what would be involved to modify a first stage Merlin to a second stage one . If it is easy you could convert 9 first stage engines after 9 flights to expendable second stage engines.

Not a bad idea if using the same propellants in first and second stages.

Offline tnphysics

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Re: Manned spacecraft with integral upper stages
« Reply #19 on: 12/09/2012 07:04 pm »
You're still throwing away a Merlin every flight though. Why would that be needed vs. having the Merlin and its tankage on the spacecraft?

Offline joek

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Re: Manned spacecraft with integral upper stages
« Reply #20 on: 12/09/2012 07:05 pm »
You're still throwing away a Merlin every flight though. Why would that be needed vs. having the Merlin and its tankage on the spacecraft?
Because it's cheaper?

Offline tnphysics

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Re: Manned spacecraft with integral upper stages
« Reply #21 on: 12/11/2012 12:57 am »
You are probably right, at least for now. If flight rates were high enough to justify separate vehicles, my idea might have merit, but flight rates are way too low for now. The analogy I have is dedicated cargo and passenger aircraft vs. one aircraft that can do either job, but is optimized for cargo.

Offline kkattula

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Re: Manned spacecraft with integral upper stages
« Reply #22 on: 12/11/2012 02:53 am »
It helps to do some simplistic cost analysis:

First stages are relatively simple, just tanks and engines, but they're expensive because they're huge.

Second stages are much smaller, but still expensive because that's where all electronics are. And excess weight is far more critical, so they're optimised to the maximum degree.

So duplicate some of the electronics in the first stage, add recovery systems and make it bigger to compensate for lower payload fraction, making it even more expensive. But re-use it to spread that cost over multiple flights.

Remove the expensive bits from the second stage, and put those in a re-usable orbiter. Don't optemise second stage as aggressively.



Offline dmc6960

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Re: Manned spacecraft with integral upper stages
« Reply #23 on: 12/11/2012 08:39 pm »
I've always envisioned a 3 stage setup for this.  I'm also drifting into a 3-stage partially reusable setup here...

First stage is built like a tank.  6 ground-lit, pumped, gimballed engines.  First stage has all ground-support built in for all stages, is self supportive, and capable of a fully fueled takoff and landing from a clean concrete pad.  It partially surrounds the second stage and is also cross-fed with the second stage to provide additional fuel for intact abort needs.  This stage handles predominately gravity and drag losses with a little horizontal.  Stage returns to launch site propulsively, perhaps stabilized by a drogue during initial descent.

Second stage is a minimal design.  1-3 high expansion fixed pump-fed engines (high expansion versions of the 1st stage engines?)  Verniers for steering (perhaps future landing).  Balloon tank.  No loaded landing capability (perhaps future empty landing).  Handles majority of horizontal dV.  Initially disposed of, but perhaps future return and landing with a second burn right after 3rd stage separation (ballistic trajectory?) to do almost one full orbit and return to launch site.

3rd stage is a large ogive capsule (think ATK's Liberty launch abort aeroshell).  4-6 spherical, high pressure, and highly insulated propellant tanks in its base-"propulsion section".  A single pressure-fed, gimballed engine in the middle firing through a door in the base heat shield.  After firing, a nozzle extension retracts or separates, and the door swings shut (like the Shuttle's propellent umbilical doors).  Final capsule dV to orbit ~2000-2500 m/s.  From rough calculations I've done this is about the most dV you can get with these physical restrictions, regardless of size. Keeps enough propellant reserves for orbital maneuvering and powered landing.  Top section of capsule contains pressurized cabin.  Nose has small hinged fairing (1 or 2 parts) and contains docking ring and other sensors.  Possible (and much more complicated) setup includes tunnel down to airlock/bathroom?/hatch near base of capsule against one side.  This would allow for near ground-level exiting after landing.  Abort/landing motors would be spaced around the perimeter of the capsule similar to the ATK Liberty abort motors / SpaceX superdracos.  Would either have 4 groups of 2 (like Dragon), or 6 relatively evenly spaced.  Extendable/retractable solar panels and radiator.  Re-entry is guided with offset cg lifting and/or deployable steering flaps between the abort/landing motors.  Final approach is on a drogue before landing motor firing.  In the event of problem the drogue would pull out an emergency main parachute or three and the crew cabin would lift off of the propulsion section for a "hard" landing.  Propulsion section could still try to save itself once clear of the crew cabin.

Other general concepts...

Intact abort and landing during all stages of flight.  Eventually to allow inland orbital launches with overflight of less-populated regions (think New Mexico spaceport).  Landing ability of 2nd stage would need to be developed first, or perhaps guided parachute?  Possible emergency landings would then take place over land within easy reach of emergency personnel.

Nearly 100% self supporting.  Including structural support, ground service equipment, orbital support.  First stage has everything necessary to prepare and launch.  Propellants all loaded through semi-tuck-trailer based tanks with remotely operated controls.  Drive up, plug in, fuel, un-plug, drive away, launch.  Ground support trucks could be driven over highways to any launch site and refueled with standard tankers.  Mobilization from hanger to launch pad to be done with self-rigging Self-Propelled Modular Transporters (typically used to move pre-built highway bridges) under the legs.

Stacking of stages could be in a specially built hangar with crane, or a mobile purpose-built gantry crane.  Lets give that mobile gantry crane a curtain around it just because.

Crew loading/support/evac also handed by a specially designed truck trailer.  "White Room" rotates up 90º hydraulically on a long arm to vertical.  Room itself is mechanically rotated/linked to maintain its level.  Lowering is done with a gravity brake, and would be designed so the truck could start driving away while it is still lowering in an emergency.  Stabilization outriggers would also be equipped with wheels to enable driveaway while still deployed.  Once fully lowered the white room would sit in a reinforced shell.

All stages using same propellants, no toxics, no/minimal helium.  Propellants either LOX/CH4, or LOX/C3H8 (subcooled).  RCS fueled by high pressure gaseous storage of orbital propellants.  Pressurization provided by heat exchangers vaporizing propellants back into their tanks.  Nitrogen where possible for purging.

Any mechanical disconnects for normal operation have explosive backups in case of mechanical failure.  Solar panels could disconnect in case of failure to retract.

Engine cycles would probably need to be gas generator or staged.  I'd like to do expander but the power needs are probably too great.  Engines need to be designed with minimal support needs.  Be able to light or shut down several times, even unplanned and on-the-fly.  Abort engines could be ignited via a small torch igniter running continuously during the ascent when needed.  1st stage and abort/landing engines need good throttling, 2nd stage moderately, and 3rd stage main engine probably not so much.

1st and 3rd stages will have bad mass fractions due to the sub-optimal design and margins needed.  2nd stage designed to minimal needs which is why it may not be able to be reused.

Overall 3-stage stacked profile may be similar to that of an elongated egg.


This is just a general summary of what I've been thinking for a long while now, probably going on 5 years.  Its been interesting and nice seeing real systems being developed using similar ideas.  Perhaps I'll start a dedicated thread eventually outlining every detail I can think of.
-Jim

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