Project The "Small Orbital Craft" Project

Cobalt

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An entire half of the spacecraft opens for EVAs. Is that a bit much?
Perhaps...

Anyhow, the capsule itself is nearly too small for a crew transfer tunnel. It's only 0.95 meters wide. To EVA the entire ship could be depressurized, its not a very large loss. The pilot himself is somewhere around, say, 50-60 percent of the volume in the craft already! But an inflatable airlock/docking port is interesting.

I thought about the inflatable dock, but it raised too many questions, at least to me. It seems a logistical nightmare.

Anyway, a quick update, I've remade the first stage, insofar as it's a stick and an engine. I'll do the fins soon enough.

Question, related to the docking situation. What's the size of a docking port on the ISS? Depending on the reply here, I'll make a final decision on scrapping or looking into an idea.


-----Posted Added-----


Allright, fins added, they're not the best, but, this was never going to be in the first place. Though, as bad as the fins are, the engine is worse. I'm going to try to make a new one before too long.


-----Posted Added-----


Just to prove I'm not yanking everyone's chain, here's the engine redone and the fins cleaned up from the first attempt.
picture.php

I can scale it all as necessary if/when I need to.

Ugly, huh? The engine is going to be redone even further. I still don't like it.
 

Cobalt

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Looks nice and clean so far

Thanks! I've redone it at least four times, a couple of them from scratch. I'm happy with where it is for now, which is the above shot. Save the engine, which I'll work out eventually.
 

cjp

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Ugly, huh? The engine is going to be redone even further. I still don't like it.

It's nice. You can do the more detailed modeling with textures, to keep the number of polygons low. It will be a real nice first stage.

I'm not an expert, but if it has a solid fuel engine, I'd say it would look a bit like the Space Shuttle SRBs, right? The nozzle's throat of your rocket seems to be a lot more narrow though...

Why use fins? I know some rockets (e.g. the V2, the SCUD and many derivatives) use fins, but in most modern designs it has been replaced by something else (I guess thrust vectoring, but maybe also RCS). I guess the Saturn V is one of the latest designs with fins. You can't use fins on the second stage anyway, as it will operate out of any useful amount of air.
 

Cobalt

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It's nice. You can do the more detailed modeling with textures, to keep the number of polygons low. It will be a real nice first stage.
Yeah, that's a good plan.
I'm not an expert, but if it has a solid fuel engine, I'd say it would look a bit like the Space Shuttle SRBs, right? The nozzle's throat of your rocket seems to be a lot more narrow though...
I'll have to do a tad more research. For now it's just a rough shape.

Why use fins? I know some rockets (e.g. the V2, the SCUD and many derivatives) use fins, but in most modern designs it has been replaced by something else (I guess thrust vectoring, but maybe also RCS). I guess the Saturn V is one of the latest designs with fins. You can't use fins on the second stage anyway, as it will operate out of any useful amount of air.
Fins just look so nice and old-school. Plus it was on the original design. I wasn't planning on making them animated or anything. If they prove problematic, they'll be dropped.
 

penlu

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Sorry I haven't been on so often, school and camping, ya know. Stuff. Anyhow, I think the engines are really nice. Remember, though, that engines for use in vacuum are meant to be very narrow and long, and the engine looks like it's meant to be used in a vacuum. The rocket is as wide as the SOC, reemember. That's 0.95 meters. Is that a bit narrow? And if the first stage burns for 250 seconds at 5 Gs and the second stage for 150 seconds at 3 Gs, is it possible to hurl a cargo into orbit?

Should we use fins? Well, I think it would be a lot simpler than using thrust vectoring or RCS. RCS, maybe, but the SOC has some that could control the rocket. It could get a bit difficult, though, because the SOC is at the end of the long stick.
 

Cobalt

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I've been having some rough times at home lately. Mental health issues and the like, so I've not really put a lot into this. I'm really sorry, I do want to finish this thing up, I've just had to straighten some stuff out first. I'll still need some help, and I'm still at a loss as to the docking situation. We'll figure it out later, though.
 

penlu

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It's totally fine. As for the docking, does a direct crew transfer HAVE to be performed? Or can the pilot EVA over to the station or whatever?

I think there's a picture on the first page. The nosecone would open and a couple of spokes would fold open. My only question is whether or not those things like gravity-gradient torque would rip the spokes apart.

How big are the docking latches anyways? Like on the Space Shuttle. How large are the actual clamps?

I remember something suggested in a previous post, that the craft should just be grappled by the maneuvering arm. It sounds pretty attractive, but maybe the arm would have to be used for something or other. Maybe make a port for it? Clamps shouldn't have to be too big, I'd bet that a team of people could easily lift the spacecraft. Remember that it is tiny.

In fact, I really don't think a direct transfer ould be possible. The tunnel would be larger than the spacecraft itself!
 

tblaxland

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I remember something suggested in a previous post, that the craft should just be grappled by the maneuvering arm.
Yeah, HTV style:

It sounds pretty attractive, but maybe the arm would have to be used for something or other. Maybe make a port for it? Clamps shouldn't have to be too big, I'd bet that a team of people could easily lift the spacecraft. Remember that it is tiny.
Because it is too small for attaching to a docking port or CBM, what if you put a LEE (latching end effector, perhaps retracting) on the top and a PDGF (power data grapple fixture) on the side (or nose, or tail). The SSRMS can then grapple the vessel and move it over to a PDGF on the station (eg, nadir of Harmony) and the vessel can attach itself to the station using its LEE (just like the SSRMS attaches Dextre to the station). The SSRMS can then be used for other ops or even to aid the astronaut to EVA over to Quest for ingress to the station.
 

wehaveaproblem

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You've really set yourselves some tough design constraints keeping this so small, but it's an interesting dev discussion to follow.

A thought on docking. It must be able to happen to make the capsule worthwhile. If you go down the EVA route then the passenger must travel from launch in his full EVA gear, which is going to take up some more of that precious (cramped) space inside the capsule. Plus EVAs are inherently dangerous. Surely having the passenger in an unpressurised suit in a pressurised cabin is more space efficient? Plus would allow easier use of internal systems as there is no bulkiness.
But then how do we dock? ah yes, my idea... What about a purpose built docking unit that can be attached to the space station? The idea would be to make it a sort of female version of the male capsule, so the whole thing slots into a 'hole' nose-first with just the heat shield (bottom) left exposed to space. The capsule door/side opening, would then be inside a little pressurised port so it can be opened unsuited... ?

just a thought.
 

HiPotOk1978

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Reading these posts I can imagine a guy somewhere looking up into the sky then going back into his garage to work in his rocket that is going to take some private citizen into space, sounds like the movie "The Astronaut Farmer" to me... I can't wait to get my hands on this bad boy...

If your still working on your motor, this might give you an idea... Why go Liquid, or solid when you can go HYBRID!!! NO2 can be liquidified (is that a word) at room temp, AND can be made at home with a little risk... You get throttle control, restarts and depending on what your burning... lots and lots of exhaust smoke. I believe there are some unique performance issues to hybrids though so you may wanna look into...

http://en.wikipedia.org/wiki/Hybrid_rocket

ground lit solid motor is great, if your math is dead on, I would not want my only way to orbit to be a solid motor.... just my opinion ofc
 

Cobalt

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Okay. The idea I was sitting on regarding docking is entirely based on the dimensions of the docking ports on the ISS itself, and the craft's size.

If size permits, place the docking port itself directly over the pilot's head. This would be rather difficult to accomplish, but, so far it seems to be the most practical (as far as transferring the pilot to the station or whatever else he/she may dock with.) Imagine, if you will, that once docked, the hatch opens once pressure is equalized, and the pilot could literally just pull themselves into the station. Once it's time to get back in, they just go feet first. Think Formula 1 car sort of entry. Hatch closes, airlock depressurized, head on home.

This negates the issue of needing to wear EVA gear throughout the flight (and would save on precious weight, too.)

It may not be possible, mind, again as it's entirely size dependent, but it seems at first glance to be do-able.
 

HiPotOk1978

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This negates the issue of needing to wear EVA gear throughout the flight (and would save on precious weight, too.)


The EVA gear is more than just walking in space. Crews wear those in case of depressurization during launch as a survival suit so they can stay conscious to perform emergency procedures.

An dea I had for EVA to a station was why not do the spacewalk, just have a umbilical like a slinky come out so there is no fear of drifting away.

The next question about this craft is it disposable... after you crack it open to get out, can u close it back up for a reentry? or does it just burn some RCS thrusters and burns up...
 

penlu

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Yeah, HTV style:
YouTube - H-II Transfer Vehicle


Because it is too small for attaching to a docking port or CBM, what if you put a LEE (latching end effector, perhaps retracting) on the top and a PDGF (power data grapple fixture) on the side (or nose, or tail). The SSRMS can then grapple the vessel and move it over to a PDGF on the station (eg, nadir of Harmony) and the vessel can attach itself to the station using its LEE (just like the SSRMS attaches Dextre to the station). The SSRMS can then be used for other ops or even to aid the astronaut to EVA over to Quest for ingress to the station.

Exactly. There's still the crew transfer problem, though. If everyone wants direct crew transfer through dock, then we'll have direct crew transfer!

But then how do we dock? ah yes, my idea... What about a purpose built docking unit that can be attached to the space station? The idea would be to make it a sort of female version of the male capsule, so the whole thing slots into a 'hole' nose-first with just the heat shield (bottom) left exposed to space. The capsule door/side opening, would then be inside a little pressurised port so it can be opened unsuited... ?

just a thought.

That is definitely a good way to solve the problem. But then the objects being docked to would have to be redesigned. I can't imagine that kind of thing on the Space Shuttle or something. And there's always the problem of the seal failing. It would be better just to go with an airdock that can be pressurized, but there are still the same risks. I'm afraid of the airdock doors ripping off while the pilot is floating inside.

ground lit solid motor is great, if your math is dead on, I would not want my only way to orbit to be a solid motor.... just my opinion ofc

Yeah, that's a problem. Hybrids sound very good. I didn't think of that.
 

penlu

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What, Ares I is solid-fueled?

Anyhow, I asked some people at school about the docking problem. One suggested an inflatable tunnel around the door. I think that would be hard to fit, though. Last night, my brother suggested using the last stage of the ascent vehicle as an adapter module, but that doesn't solve the problem of getting a guy into it. But after looking back at wehaveaproblem's idea (the "female version of the male capsule") I realized that the part of the space station that the SOC docked to could be launched, deflated, under the SOC on the rocket instead of having to get the space station or whatever is being docked to revamped.
 

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I suppose it wouldn't be too unreasonable for either the station to keep a special adapter or an inflatable tunnel mounted on the SOC (like the early Soviet inflatable airlocks).

I've always felt that the SOC is a little to small to have anything more than a door, and maybe an inflatable adapter seal. I think its unrealistic for it to be capable of spacewalks without capsule depressurization.

Oh, and I'm excited to see this project slowly come to fruition. :)
 

Cobalt

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I'm guessing the lack of comments means my idea was bad. Which I thought it might be.
 

wehaveaproblem

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I don't think 3 pages of discussion indicates a bad idea, quite the opposite.
As to your latest idea of having the dock at the top, it could certainy work.. It would essentially be like cutting the nose off a DG, and sticking a heat shield on the bottom. I like the concept.
 
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