DIY Space Capsule Geometry and How NASA Stole My Idea 53 Years Ago
A substantial amount of time is invested in getting all subsystems placed and geometry identified for our next-generation DIY space capsule Tycho Deep Space II. The previous capsule was more an ad hoc working process because not all subsystems were represented.
This time a multi-development process is taking place with boilerplates used to verify different systems before the final design of the aluminum flight version will be locked.
Since we are changing the diameter from 2 m to 1.6 the overall geometry has to change as well but we are still capable of performing a complete technology transfer of previously tested subsystems such as parachutes, external control panels, LES systems. However, buoyancy performance and handling based on this new geometry is unknown and not before scaled or real size testing has been performed, can we know the geometries and volumes needed for this.
Early in this development process we decided to divide the ship in two parts: Lower part pressurized cabin and upper part unpressurized recovery section. As soon as the pressurized section is understood based on seating size, post splash-down seating orientation and hatch handling we can actually begin the flight version production of this. However, the top part will require boilerplate testing and the production of this unpressurized part probably begins later on in the process.
Even though not all subsystems are understood I create design sketches to understand the complete system during the process. Below is my latest sketch of Tycho Deep Space II. I did not use any rulers and measurement, so angles and sizes might be a bit off.
The latest version of this capsule design can be downloaded for SolidWorks 2012. You are welcome to play with the model and even E-mail me a revised design.
Next week our 1/3 scale re-entry (dished-end) shields will arrive and I will begin the production of small boilerplates for buoyancy and LES testing. A couple of days ago I just discovered that NASA also performed these tests in 0.33 scale models to understand LES stability . How dare they steal this idea almost 53 years ago? But then again… I might have stolen an idea or two from NASA. Fair enough!
When a 1/3 scale boilerplate is created we will be testing capsule performance in water. This will show if we will be needing uprighting-bags to get the hatch facing towards the sky and the astronaut lying in a correct position and even reveal if the upright positioned seat actually makes any sense at all. The need for uprighting bags will like have a profound impact on the volumes needed for this, inside the recovery section.
If nothing turns out to work, related to the seat orientation post splashdown, I might have to revise the interior design of the capsule and change the geometry of the pressurized compartment completely. This is why I will not begin the expensive development of the flight version yet. However, if we get something that makes sense I will perform similar tests using a real scale boilerplate. Only after evaluating of theses tests the design, for the flight version, will be locked.
LES test will also be performed beginning with 1/3 scale boilerplates. We need to see this rescue system fly with no instability.
It is a mighty puzzle. But one of the best puzzles I have ever tried to solve…
Kristian von Bengtson
 Springer, Praxis Publishing. “Project Mercury – NASA´s First Manned Space Programme” page 182 – ISBN 1-85233-406-1