Gemini: We can rebuild it, we have the technology

[grooble]

You said the original gemini was made from Titanium and Berrylium. Can lighter, stronger bulkheads be made from todays technology? New alloys, nanotech, composites? <br /><br />

 

[mrmorris]

<font color="yellow">"Can lighter, stronger bulkheads be made from todays technology? New alloys, nanotech, composites? "</font><br /><br />Beryllium would likely not be used for a modern Gemini's heat shielding -- lighter and better shielding has since been developed. Titanium remains a strong contender, however. It's light, strong, and resistant to high temps.<br /><br />However -- the structure itself isn't something I've been targeting for reducing weight on (saving the primary heat shield as mentioned earlier in the thread). Using modern electronics and optimizing the Gemini-3X for space-station operations provides for massive weight reductions. <br /><br />Using modern electronics and eliminating the duplication caused by not having an expendable equipment module will slash the weight by several hundred pounds. Eliminating the fuel cells, water and food supplies, seat catapults, and other components will save close to a thousand pounds.<br /><br />Also -- while the original Gemini was pushing the limits of the Titan II -- the additional payload capacity of the Falcon V along with the weight reductions means that there is a significant reserve. I've actually shifted from focusing specifically on reducing weight to focusing on specific components -- preferably COTS -- that could be used as-is, or modified for use with a modern Gemini. Ideally I'd like to be able to come up with a laundry list of components that could be used to replace as many of the original Gemini subsystems as possible.

 

[scottb50]

The basic airframe should be rather simple, the only major problem being the TPS system attached to it. Something similar to that planned for the X-33, incorporating Titanium, might be fairly straight forward to do and not overly expensive on a relatively small vehicle as well as allowing multiple flights of the same airframe.<br /><br />Beyond that it is a matter of integrating existing components and software, not inventing them. Once the perameters are defined I would think actual construction would be straight forward. I would even think a test version could be available for the first FalconV flights. <div class="Discussion_UserSignature"> </div>

 

[grooble]

What would it cost to build one of these revised Gemini capsules?

 

[scottb50]

Ask Rutan, he could build the basic airframe in a few months. Sort of the Space version of a Homebuilt aircraft. It's not rocket science, that's the hard part. After all a homebuilder rarely, if every, builds a motor.<br /><br />The basic structure could be extremely simple light weight composite, with attached, replacable, repairable, thermal protection provisions. The only major change I would do is remove the Gemini canopies and add a docking port, at least a wash, weight wise. <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"Ask Rutan, he could build the basic airframe in a few months. "</font><br /><br />I'm not sure that composites would be a wise choice for the framing. Composites tend to burn at (in re-entry terms) relatively low temperatures. Even with heat-shielding, I don't think it would be possible. While the original Gemini was composed of TItanium and Beryllium, the shuttle orbiter airframes are composed primarily of high-grade aluminum. This is probably the material of choice for Gemini-3x. It would be **much** cheaper than an equivalent titanium airframe.<br /><br />The melting point of Titanium is 1660±10 º C (a.w. 48)<br />The melting point of Berylium is 1278±5 º C (a.w. 9)<br />The melting point of Aluminum is 660.37 º C (a.w. 27)<br /><br />I can possibly see the pressure vessel being composed of composite materials. Situated inside both the heat-shielding and the airframe -- it will likely be insulated enough from the heat of re-entry. However -- since we're not short on mas lift capability -- it might simply be aluminum as well. While heavier -- aluminum is cheaper to maintain and repair than composites. Mass is important, but money is king (up to the point where mass is costing more, of course...).<br /><br />The mental picture I have for a company working to build Gemini-3x would be for someone like Blue Origin or Space-X to partner with one of the small U.S. aircraft manufacturers (such as Cessna or Piper). This seems to be a great match for numerous reasons:<br /><br />- These firms have the design experience in building small airframes (which the Gemini capsule certainly qualifies as) and pressure vessels. <br />- They have the metalworking machinery and workforce to build the airframe.<br />- They have a great deal of experience in getting the maximum use of a small space in locating seating, avionics/controls, and stowage compartments. <br />- Much of the interior equipment can be the same used by their planes (i.e. seats, cabin

 

[scottb50]

Yeah, but it just might work. What's plan B? $48million to research doing it.<br /><br />I real doubt composites would be that much of a problem, if any, and would be a whole lot easier to work with. <div class="Discussion_UserSignature"> </div>

 

[annodomini2]

If Carbon composites were used it would be the resin used that would dictate the thermal properties, if a resin exists that can handle say the titanium threshold without compromising the structural properties of the material then it may be possible. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

I would think a Carbon/Kevlar matrix and a Carbon based resin, with a stand-off TPS system, would be more than able to handle the temperatures and would be much stronger than Aluminum.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[grooble]

Is it cheaper or lighter?

 

[scottb50]

Lighter yes, cheaper, at least up front, I doubt it. Remember though we aren't talking that big of a vehicle. <div class="Discussion_UserSignature"> </div>

 

[grooble]

But i guess reducing the weight would pay for itself. <br /><br />What exactly could you do with an updated gemini capsule anyway? Put 6 men into what kind of orbit? Dock with the ISS? Go to the Moon?<br /><br />

 

[scottb50]

Yes, Yes and No. <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>composites...would be a whole lot easier to work with.</i><p>On the contrary. Composites are, for the most part, very difficult materials to work with. You can't machine or drill them in the same way as you can with metals. They also have failure modes which are harder to predict - remember that the failing of the X-33 was the difficulty they had in manufacturing a composite hydrogen tank.<p>The fact that composites can't be worked also makes developing the prototype potentially <b>much</b> more expensive, since the slightest change requires entirely new moulds to be fabricated. All in all, I suspect that Aluminum or Titanium is the best way to go.</p></p>

 

[mrmorris]

<font color="yellow">"What exactly could you do with an updated gemini capsule anyway?"</font><br /><br />This vehicle as designed (at least the design sitting in *my* head) is only applicable for ferry operations. The craft is optimized to get six people to orbit in the simplest and cheapest fashion possible. If the weight is kept in the ranges I think possible (<5000 kg) then the Falcon V can put it into orbits ranging to about 700km.<br /><br />However, it has limited ECS and power capabilities, and there's no provisions, water, etc. Once in orbit -- it will need to rendevous with another vehicle within a matter of hours. <br /><br />The primary target, of course, is a space station -- whether the ISS or the BSS. However -- it could also be another spacecraft that has more ECS, space, etc. This craft would likely be a reusable craft designed never to re-enter the atmosphere. It could be a craft designed for anything from repairing orbital assets to lunar transport. When the Gemini returns to earth -- such an orbital craft could be docked at a space station to be refueled/resupplied.

 

[scottb50]

<<This craft would likely be a reusable craft designed never to re-enter the atmosphere. It could be a craft designed for anything from repairing orbital assets to lunar transport.>><br /><br />If you consider it could be a simple cylinder that docks to other identical cylinders, it could be used universally.<br /><br />Which comes back to a Tug being needed. If a Tug was simply one or more launcher upper stages, cylinders with engines attached, it becomes even simpler. Using the same cylinder as both the second stage and a payload container makes it even simpler. Using the same cylinders as station components, Transit Vehicle components, Lunar and Mars landing vehicle components and Lunar and Mars habitats would further reduce costs and offer a positive step beyond LEO.<br /><br />True using the same component universally makes it better adapted to some uses and overbuilt for others, but in the long run the convienience and cost savings would outweigh the compromises.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[nacnud]

I thought the initial idea for the Gemini X3 would be to get up to one of bigelows space stations, but if your looking to increase the time available before supplies run out why not use one of the inflatable nautilus modules as the extra room ie launch in Gemini X3 dock with the nautilus + kick motor + fuel and off you go.

 

[scottb50]

The LEO stations I am talking about could very well be Bigelow hotels. Dock their inflatable habitats to a core station and you have not only a hotel but a transfer station for people and payloads to higher orbits or beyond. If nothing else the people living and working at the station would need living quarters. <br /><br />I agree with MrMorris; keep it as simple as possible and outfitted for a single repeated task. Add too many bells and whistles and it becomes another Shuttle. <div class="Discussion_UserSignature"> </div>

 

[cdr6]

Taking your idea a step farther, what about a MOL module for those that want to do some yachting? Say a couple of orbits just for the fun of it..or a 3 day weekend kind of thing. The really adroit, could even even stock one up, and do a circum lunar voyage. <br /><br />The air force flew a "Blue Gemini" with a novel "hatch through the heat shield" on it's only MOL flight and was successful with the unmanned flight.

 

[mrmorris]

<font color="yellow">"...what about a MOL module for those that want to do some yachting? Say a couple of orbits just for the fun of it..or a 3 day weekend kind of thing. The really adroit, could even even stock one up, and do a circum lunar voyage. "</font><br /><br />Dunno what you mean here. The MOL was the 'Manned Orbiting Laboratory". It was the USAF concept of a space station. The Gemini was supposed to service it and act as a lifeboat. However -- there's no 'MOL module' with the type of capability you suggest. There was 'Big Gemini' which had a second cabin area 'superglued' to the back of the Gemini capsule. However -- this would be too large for the FalconV to lift. There was also no massive increase in propulsive capability that would get it to the moon.<br /><br />However -- the Gemini-3X can do the 'orbital weekend for multimillionaires' thingie. For its primary role, the ECS system needs to have enough capability to sustain six people for 3-4 times the 'expected' trip length from earth to space station. Matching orbits, docking & so forth is going to be a matter of several hours even when made on the first pass -- figure six to eight. Bump that to ten, figure the same for re-entry, then multiply by 3-4. Figure 60-80 hours of ECS for six people. The Gemini-3x then carrying two people would have an ECS capability of three times that (180-240 hours). In any event -- if some Tito-style multi-millionaire truly wanted to pay several million dollars for a few orbits of the earth, there would be plenty of capacity in the 3X without any extensions. WIth four seats removed -- it would be easily possible to add a zero-G toilet and a supplies locker for munchies. Although I dunno why you'd want to do this when a week on the station itself would probably cost less (the launch costst being divided by 5 passengers instead of by 1).<br /><br />Going lunie would be a bit harder. There would have to be a kick stage involved. Not really a good id

 

[scottb50]

At best I think a Gemini3 would be pretty cramped for extended operations. Here again you run up against the same problems that have hobbled Shuttle, if you try to make it do too much it does nothing well and the weight grows with every additional capability added. <br /><br />Dedicated orbital modules would allow simplified operations though. There doesn't need to be a difference between the structure of a LEO station or a Lunar/Mars transit vehicle, except in equipment added to the basic structure specifically for the job. <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"Here again you run up against the same problems that have hobbled Shuttle, if you try to make it do too much it does nothing well and the weight grows with every additional capability added. "</font><br /><br />Well -- the question was regarding extensions or additional capabilities possible for Gemini-3X. Obviously the first one (if designed and built for the ASP) would be optimized for getting six people from the ground to a space station. Since neither NASA nor any other government agency is involved -- hopefully 'feature-creep' won't enter the picture.<br /><br />However -- the basic design is a reasonably good starting point to other possible uses as well. For example, you'd be hard put to create a smaller/lighter vehicle for moving an equivalent amount of people/cargo from one orbit to another. Drop the heat-shield and the re-entry equipment. In lieu of the De-Orbit SRBs -- add additional propellant and ECS. At that point, Gemini-3X (Mark II) becomes a very efficient craft for moving people and equipment from one space station to another. <br /><br />With only one space station currently -- there is no need for such a craft. However, if we assume that Bigelow is going to succeed (which we have to if we're also banking on this prize), then there are liable to be two space stations, and probably three or more. Inter-station craft will be useful for a couple of reasons (at least).<br /><br />One: having people on a space station disrupts the micro-G. Therefore it's likely that a station will be needed that is unmanned except for periodic service visits. Since orbital corrections required due to atmospheric friction will *also* disrupt the micro-G conditions -- this space station will likely be placed into a higher orbit that requires fewer corrections. Therefore a very low-mass vehicle will be desirable to get to the higher orbits when service is required.<br /><br />Two: Station failures/emergencies. With more than one statio

 

[scottb50]

I would think as demand increases so would the capability, success with a FalconV could lead to a Falcon X and a 10 passenger Gemini4 or 5.<br /><br />I would also think it much easier to have mission specific Modules for in orbit operations and not depend on modified Gemini's. <div class="Discussion_UserSignature"> </div>

 

[grooble]

You could build 1-man construction pods on a falcon-V

 

[scottb50]

Why bother when you could launch a four man team? The falconV can launch 12,000 pounds, or so, the majority of it will have to be propellant though. Say a Gemini3 comes out under 6,000 pounds empty, compared to 8,000 for Gemini, the amount of propellant that could be carried by the upper stage is increased. Make the upper stage lighter and it becomes even higher.<br /><br />Not that I don't have an idea for an individual Pod that would serve as private sleeping quarters, individual emergency escape, work platform and local transportation. But first we have to get to LEO.<br /><br /> <div class="Discussion_UserSignature"> </div>