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Visual Guide – the Making of a DIY Space Capsule
Kristian vonBengtson writes "Wanna build your own space capsule capable of doing an atmospheric re-entry on a suborbital mission? Well, here are some production hints and a visual guide."
The initial stages begin with sketches on paper before moving to 3D design software. He writes, "A whole bunch of sketches were done to get some kind of initial idea of the size, subsystems layout and how to actually produce the capsule while keeping an open structure for further development and potential changes. One of the main concerns was the small size and the ability to easy install and replace avionics. This led to the decision that all external side panels will have to accommodate being taken on and off – no welding, only on the main structure." Afterward, he moves on to show the final metal cuts and how the pieces are put together via bolts and welding.
I like it. With such a high fineness ratio, I wonder a little about stability-- does it stay heat-shield down? Is there an alternate stable mode with the nose down?
I do notice a ballute-- this is probably to stabilize the heat-shield-down attitude when it's too high for a parachute to open. This may work for stability for the relatively low entry velocities needed for suborbital, although I'd be curious about the ballute holding up in hypersonic conditions.
http://www.geoffreylandis.com
I'd use my apple II computer to generate some kind of force field / inertial dampening bubble around my capsule. Then the capsule can be hastily cobbled together from household items.
I recently attended a lecture about homebrewing a spacesuit. A professor from Portland State has always been fascinated by spaceflight and high altitude balloon flight and has designed a spacesuit. His group is called Pacific Spaceflight (pacificspaceflight.com). During his talk, he discussed what goes into designing a spacesuit and demonstrated the prototype suit they designed by pressurizing the suit (and the person wearing it) to 1-2psi above the ambient atmospheric pressure. From what they learned building the prototype they will build the flight version. Their suit is at about the tech level of a spacesuit from the Mercury program. One of his main talking points was that if everyone concentrates on one aspect of spaceflight, then it can be done affordably. Copenhagen suborbitals is working on the launch vehicle and capsule, he's working on the spacesuit. Others have other pieces of the puzzle. The Pacific spaceflight suit is the suit that will be used for a suborbital flight on the Copenhagen suborbitals vehicle hopefully some time in 2015
This is a technique known to aerospace engineers for fifty odd years.
The timing of it's original discovery and implementation had a unexpected impact on space history though... NASA first encountered the same problems with Mercury - not so much because it's size, but because all the systems were packed inside one on top of each other with no provision for access. This caused many problems during assembly and launch preps as often connections had to be broken and unrelated equipment removed to get at a part that needed replacement, repair, or adjustment. So, when NASA and McDonnell (they hadn't yet merged with Douglas) were evolving the design into the Mercury MKII and eventually Gemini, they re-arranged things. They shrunk the pressure vessel a bit, enlarged the structural shell a bit, and packed as many systems as possible into the space between and behind access doors.
But Apollo's design was already largely frozen - it retained the Mercury type design of having almost everything packed into the pressure vessel. (Yes, the design sequence goes Mercury-Apollo-Gemini, out of order from the flight order.) The result was that it was extremely difficult to work inside the Apollo capsule, to track work accomplished, and easy to damage adjacent systems and equipment - damage that was later believed to have been the source of ignition for Apollo 1.
/paulharvey