Project The "Small Orbital Craft" Project

penlu

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I don't think we could have a dock on top that allowed for crew transfer. When the parachute system is taken off, the width of the resulting surface is about 10 cm. Much too small for a dock. If we were using a DG nosecone, then the ENTIRE CAPSULE would open up around the pilot. REmember that the spacecraft itself is about as large as a dock.
 

wehaveaproblem

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hmm, good point. I think you are fast running out of options then.
Unless you have the heat shield on a hinge, so it can swing open like a can, with the docking port hidden behind it, underneath the pilot, so his entire seat slides out of the bottom... ?
 

Thunder Chicken

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I don't think we could have a dock on top that allowed for crew transfer. When the parachute system is taken off, the width of the resulting surface is about 10 cm. Much too small for a dock. If we were using a DG nosecone, then the ENTIRE CAPSULE would open up around the pilot. REmember that the spacecraft itself is about as large as a dock.

How about just using an ejection seat for crewmember recovery? After re-entry, but still during free fall, a pyrotechnic hatch opens and the astronaut ejects. The capsule would be a loss, but it is a small piece of equipment anyway.
 

penlu

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I wouldn't like to be riding in a capsule whose heat shield could swing open. Plus, there's a service module in the way.

Crewmember recovery could be with the capsule. I'm not really sure the guy will have a seat anyways, more like a specially shaped rear wall.
 

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A hinge-able heat shield isn't a real danger, since all the force of reentry only pushes it into the rest of the craft, it couldn't come open. But the service module being there does kill the idea, unless the service module is detached before docking, or in fact just hinges away with the heat shield... but that's probably not practical.
 

Thunder Chicken

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Crewmember recovery could be with the capsule. I'm not really sure the guy will have a seat anyways, more like a specially shaped rear wall.

This sounds like a super-MOOSE. Maybe something like this?:

A conic capsule that opens like a clamshell (i.e. the bottom heatshield is one piece, the cone is the other, connected with a hinge). Pilot EVAs to the heatshield part, straps in, closes and locks the shell. After re-entry, the conic part separates completely (stripped away with a small drogue chute). Another small drogue on the pilot's chest deploys, pulling him out of the heatshield where he/she can then deploy a conventional back-type automatic parachute. No ejection seat needed.
 

James.Denholm

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Herm, that MOOSE thing looks scary. I sure wouldn't want to do that...

If we're still talking about docking problems, what about:

A. Making the craft EVA-only, no docking at all. Pilot would pilot craft over to a RMS on station, which grabs hold of the ship, and pilot would then EVA to an airlock.

or...

B. A sort of inflatable/unfoldable (perhaps also disposable?) docking ring/umbilical tube thing, which fits over the airlock/cabin hatch of the SOC.

I suppose that both these ideas would require a cabin hatch, though. Is the craft going to have a cabin hatch?
 

penlu

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Maybe something like this?:

A conic capsule that opens like a clamshell (i.e. the bottom heatshield is one piece, the cone is the other, connected with a hinge). Pilot EVAs to the heatshield part, straps in, closes and locks the shell. After re-entry, the conic part separates completely (stripped away with a small drogue chute). Another small drogue on the pilot's chest deploys, pulling him out of the heatshield where he/she can then deploy a conventional back-type automatic parachute. No ejection seat needed.

Problem: The heatshield is the same diameter as the rest of the spacecraft, or 0.95 meters. I don't think that the pilot will be able to lay supine on the shield. I guess that the top part of the capsule could be stripped off by a drogue upon completion of reentry, but this would add extra parachutes, not save space.

If we're still talking about docking problems, what about:

A. Making the craft EVA-only, no docking at all. Pilot would pilot craft over to a RMS on station, which grabs hold of the ship, and pilot would then EVA to an airlock.

or...

B. A sort of inflatable/unfoldable (perhaps also disposable?) docking ring/umbilical tube thing, which fits over the airlock/cabin hatch of the SOC.

I suppose that both these ideas would require a cabin hatch, though. Is the craft going to have a cabin hatch?

A. was my original idea, B. was an idea we came upon. Of all of the ones involving direct transfer we've come up with, I think that the type like B. was the best.

And yes, there will be a cabin hatch... but it's one entire side of the spacecraft.


-----Post Added-----


I just want everyone to know that there are some other ideas and discussion at the original thread. See link on first page.
 

Thunder Chicken

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Problem: The heatshield is the same diameter as the rest of the spacecraft, or 0.95 meters. I don't think that the pilot will be able to lay supine on the shield. I guess that the top part of the capsule could be stripped off by a drogue upon completion of reentry, but this would add extra parachutes, not save space.

The parachute requirements for this whole system really aren't any bigger or technically complex then those for an ejection seat. The drogue could be contained in a container maybe 4-6 inches on a side, and deployed with an inertial slug (imagine a small gun which shoots a heavy bolt that is attached to the drogue, opening and pulling the drogue out of the container). The personnel chute could be a back-style type (which can be very thin and unobtrusive). The pilot chute (which could be stuffed in a pocket) could serve as man-ship separator.

The form factor of the shield is a problem - Soyuz seats curl the crewmembers up with their knees in their chest, but I think 0.95 m is still too small to accommodate that.
 

penlu

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Well, maybe it is too small. I fit, at least, but I'm 12, so I guess that doesn't count. I measured my dad, and he fit-just barely, into ~0.8 meters. I think that the rest of the space would be taken up by other things. I'd say the crew cabin space is the size of an average chair.
 

Lunar_Lander

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@Penlu: The idea of yours really sonds promising and cool! And even cooler is that you are developing it from scratch as a 12-year old! I really appreciate your work!

Hmm, if you want to dock, you would want to dock with the ISS. But I understand that you have to do some maneuvers to get the rendesvous right (which needs engines, just as de-orbiting also) and then quite some RCS fuel for maneuvering around the station. Can it carry that fuel and the engines for that?

Also, why would you send one man with such a small craft to ISS? You can't bring scientific gear with you, no consumables or other needed things. It could be an escape pod though...that'll be cool :)!

I would say that if you don't have reasons to go to the ISS, you could discard the docking ability. Could save you from some headaches.

And please don't feel discouraged in any way! I just was talking about the practical applications for the craft.
 

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How about just using an ejection seat for crewmember recovery? After re-entry, but still during free fall, a pyrotechnic hatch opens and the astronaut ejects. The capsule would be a loss, but it is a small piece of equipment anyway.

Unfortunately this means putting an ejection seat inside the capsule, which means more stuff and explosives. Moreover, if the cremember becomes injured in any way, the ejection may well kill or maim him. Keep in mind that ejection is a very traumatic experience and you can't exactly do a large number of ejections before being permanently grounded due to spine damage.

They used ejection seats on the Vostok because they hadn't the means to brake the capsule before impact. As soon as they developed the cushioning rockets, they discarded the thing.
 

Thunder Chicken

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Unfortunately this means putting an ejection seat inside the capsule, which means more stuff and explosives. Moreover, if the cremember becomes injured in any way, the ejection may well kill or maim him. Keep in mind that ejection is a very traumatic experience and you can't exactly do a large number of ejections before being permanently grounded due to spine damage.

A "zero-zero" seat would be overkill in this application (the seat is almost the size of the ship, and a stable separation would be difficult). When I realized the size of the ship being considered, I recommended some small drogues, one to separate the cone from the heatshield, another one to separate the pilot from the seat, and then the pilot deploys a conventional back-style parachute. We're just looking for a system that gets the pilot a means to get away from the ship (falling at near terminal velocity in the low atmosphere, maybe at 100-200 mi/hr), separating, and deploying a normal parachute. There are off-the-shelf automatic releases that could deploy all of these drogues and separations even if the pilot were injured or disabled.
 

Ghostrider

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Well, why not simply have the craft break apart around him, like the capsules from Starship Troopers?
But then again, why separate the crewmember from the spacecraft? It could be braked by cushioning rockets and airbags, both proven technologies. I'm not too keen in having the crewmember make landfall without the craft, because you're exposing them to additional risks (crewmember incapacitated or wounded), and should the capsule end in a hostile environment, the shell would provide protection from the elements.
 

penlu

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An ejection seat wouldn't fit anyways.


Check out the Parom. The space station it services would have to keep an adapter module of its own.
 

penlu

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Sorry for the bump, but the other thread has been having a bit of development as well. Nothing new, but it would be good for someone to input there too.
 

penlu

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I found that the docks of the ISS are about 1.2 meters wide. That is about 25 cm more than the diameter of the SOC itself! I think direct docking is now completely ruled out. A docking adapter or something like it will need to be used. I think it would be good to include an inflatable adapter just below the SOC on the rocket. Unfortunately, the final correction will then be screwed. I think that it probably couldn't put much more than itself into orbit. If it did manage to get the adapter up, then the capsule would nose into the side of the adapter module (adapter is cylindrical) and dock to the space station using one of the ends of the adapter. In fact, a double-ended adapter could be used to connect spacecraft and provide an SOC berth. The dock of the SOC will definitely be much different from the common berthing mechanism.
 

penlu

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Sorry for the bump.

This would be beneficial to almost all small spacecraft that use lithium hydroxide canisters for carbon dioxide scrubbing. Look at Lithium peroxide. It gives off oxygen as it absorbs carbon dioxide, so some mass or time could be saved because oxygen will be used up more slowly (or less will need to be brought along). This opens up a bit of space for something else.
 
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