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   EggCEV - The "bell-shaped" Orion   

If you have read my articles, You know that I don't like so much the capsules, since I think that we need a little, safer and cheaper new-Shuttle for a REAL future large access to the space (as I've explained in my VISUAL article).

But, I know that capsules are the best and simplest vehicle to perform an earth-moon-earth travel with an earth-direct re-entry (like required in the ESAS plan).

Then, why don't build the BETTER capsule possible?

I've many suggestions to improve the Orion design and the first of them is to change its design from a "cone-shape" to a bell-shape like the image in this page and similar (but not the same) of other bell-shaped (and very reliable!) capsules like Soyuz and Shenzhou.

The original 5 mt. cone-shaped CEV seems "big", but it's not completely true, since the two angles of the cone can't be used to increase the internal space for the astronauts!

My suggestion is to design a bell-shaped capsule (I call the "EggCEV") to have MORE internal space (probably 30%+ more than a cone-shaped capsule) with an external diameter of only 4.5 mt. (or less) that is very good to build a 4.5 mt. only (then, more aerodynamic) Ares-I 2nd stage or to fit many different (ready available) EELV's core stages, like the AtlasV, DeltaIV, Ariane5, etc.

Of course, the Orion weight must remain the same as planned, or (thanks to the higher internal space) it may be increased a little bit to add extra life-support (oxygen, water, food) very useful for longer missions or (simply) for better redundancy (that is very, very, very important, since there are not Wal-Mart stores in space!).

The larger Orion internal volume will give more space for the astronauts in the six-seats (ISS rescue) version, more space to send/return cargo and experiments to/from the ISS and an internal space higher than "minimal" (as allocated in the ESAS plan) for samples and experiments return from the moon!

I compare the EggCEV to a "bell" (like Soyuz and Shenzhou) to avoid any doubt it can safely reenter on earth but its "egg" shape (not evaluated in the ESAS plan) has some interesting and useful advantages over a smaller diameter, more aerodynamic and an higher internal volume for the astronauts and cargo.

The "egg" has (I think) two great advantages at re-entry (compared with the cone-CEV and the true-bell Soyuz) explained in this image:

The first is a better distribution of the hot flux under the TPS that detaches faster away from the capsule thanks to its aerodynamic.

The second is a lower CG that increases the monostability of the capsule and a ballistic re-entry that is safer for the crew especially in case of failure of the control jets or a wrong/delayed use of them.

Of course, the "egg" needs study, calculations and tests, but I think that it may result better and SAFER than (both) the cone and the true-bell.

PS - The CG of the three capsules are not tested or calculated (then may be different in real vehicles) but in my drawing have only the purpose of a comparison between an higher and lower CG.

August 30 - 2006

>>>>>>  If you talk/discuss about this argument on space forums/blogs/websites/magazines/articles please refer to the source of the idea and/or put a link to this article. Thank You. <<<<<<<<<<

Copyright © 2006 Gaetano Marano - All rights reserved - The base images used are © NASA and Lockheed Martin

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