Apollo1 vs Apollo2

(Lorenzo Baldi) wrote in
:

Il Fri, 02 Dec 2005 21:39:27 -0600, "Jorge R. Frank"
ha scritto:


The article fails to distinguish between ascent g-forces (typically 1
g) and the g-forces experienced during TLI (most likely fractional-g).
Fractional-g eyeballs-out is not likely to be excessively
uncomfortable, and as others have noted, it has been done before. The
author is grasping at straws if this is the most serious obstacle he
can think of against the proposed architecture.

Well, I think the economical concerns are interesting too. Just to
mention one of them, 5 SSME lost every lunch are a LOT of money.

Yes, the economics are a much more compelling obstacle. Negative G's
aren't.

Which begs the question of why Bell thought the latter was even worthy of
mention in his article, other than padding the word count and possibly
confusing the issue.

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In article .com,
Rusty wrote:
http://prod.nais.nasa.gov/eps/eps_da...OL-001-002.doc
From the drawings, it appears that the CEV command module has four
forward facing docking windows, four side windows and one window on the
side hatch...

Does look that way. Interesting that they think there's no problem in
putting windows on the "windward" side of the capsule. (Because such a
capsule reenters tilted, with one side of the cone surface nominally
parallel to the airflow, that side gets rather hotter than the "lee" side.
Apollo deliberately put the hatch, the windows, and the thrusters on the
lee side.)

The CEV service module rcs quads seem to have eight rocket
nozzles each.

For a guess, that's internal redundancy: each quad has two independent
four-thruster systems. (Can't be because they need the extra thrust --
they're developing new thrusters anyway, so they could just make them
bigger.) Seems a bit on the paranoid side.

The Lunar lander rcs quads seem to have six rocket nozzles each.

If they're doing attitude control during ascent with the RCS, as Apollo
did, roll control (for rotation around the main-engine thrust axis)
generally takes rather less authority than pitch and yaw.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

In article ,
(Henry Spencer) wrote:

In article .com,
Rusty wrote:
http://prod.nais.nasa.gov/eps/eps_da...OL-001-002.doc
From the drawings, it appears that the CEV command module has four
forward facing docking windows, four side windows and one window on the
side hatch...

Does look that way. Interesting that they think there's no problem in
putting windows on the "windward" side of the capsule. (Because such a
capsule reenters tilted, with one side of the cone surface nominally
parallel to the airflow, that side gets rather hotter than the "lee" side.
Apollo deliberately put the hatch, the windows, and the thrusters on the
lee side.)

Could be one more thing unknown to today's novice designers?

On Thu, 8 Dec 2005 08:46:49 -0600, richard schumacher wrote
(in article ):

In article ,
(Henry Spencer) wrote:

In article .com,
Rusty wrote:
http://prod.nais.nasa.gov/eps/eps_da...OL-001-002.doc
From the drawings, it appears that the CEV command module has four
forward facing docking windows, four side windows and one window on the
side hatch...

Does look that way. Interesting that they think there's no problem in
putting windows on the "windward" side of the capsule. (Because such a
capsule reenters tilted, with one side of the cone surface nominally
parallel to the airflow, that side gets rather hotter than the "lee" side.
Apollo deliberately put the hatch, the windows, and the thrusters on the
lee side.)

Could be one more thing unknown to today's novice designers?

Or it could be that the proportionately-larger CEV entry module will
have a larger (e.g., thicker) boundary layer for similar Reynolds
numbers during entry, reducing the heat loads for the windows.
However, having not done or seen any CFD or wind tunnel analysis, it's
hard to say. I will say, however, that the general Apollo capsule
shape has been studied more extensively than probably any other
civilian entry shape. There's a LOT of existing data going back a long
way.

--
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