CEV Payload

On Mon, 9 Jan 2006 15:12:06 -0500, "Jeff Findley"
wrote:


"Von Fourche" wrote in message
k.net...

Question about the future NASA space vehicle that's supposed to
replace
the space shuttle:

Will this thing have the payload capacity of the current space
shuttle?
I was always told you could fit a school bus in the payload area of the
space shuttle. With the current shuttle, don't they put a lab section in
the payload compartment or a satellite to be launched and a mechanical
arm?

I've seen a few diagrams of the CEV on the net. But all I've found
are
the diagrams of the main area were the astronauts sit and operate the
craft.
I have not seen any area where they could put satellites and such.

Is this thing going to have a lab/living area and mechanical arm?
Will
they be able to do with the CEV what they can do now with the shuttle?

If they plan on sending this thing to Mars in the far future isn't it
necessary they have a big lab/living area?

Thanks!

Try: http://www.nasa.gov/

Once you watch, or skip, the intro, look for the links under "The Vision for
Space Exploration". The first one, "NASA's New Spaceship" ought to help.
Come back when you have meaningful questions.

Jeff
I have a meaningful question (to me) that has most likely been
addressed in the past (I haven't been reading for a while).
I think I remember a thread or two about the original GE Apollo
design, which was very similar to the Soviet family of capsules, is
the more versatile design.
So why did NASA revert to the Apollo cone design?
If there has already been a thread about this please point me in the
right direction so I can read the comments.
Thanks,
Seagull

In article ,
Seagull wrote:
I think I remember a thread or two about the original GE Apollo
design, which was very similar to the Soviet family of capsules, is
the more versatile design.
So why did NASA revert to the Apollo cone design?

The GE/Soyuz design is more versatile, but it's also more complicated and
heavier, so it isn't necessarily superior, depending on what you want to
do with it. With CEV as with Apollo, NASA's design ideas appear to have
been dominated by short-term concerns, optimizing for the job at hand
rather than for longer-term needs.

(Arguably the right way to do a return to the Moon is to design the
vehicle for economical resupply of a lunar base -- which would favor
reusability even at the expense of greater weight and complexity -- and
accept that it would be suboptimal for short preliminary visits. Instead
we get "Apollo on steroids" and nothing mo a vehicle designed for
short visits -- not as short as Apollo's, but still short -- with vague
hopes of later modifying it to do a half-baked job of resupply.)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Henry Spencer wrote:

The GE/Soyuz design is more versatile, but it's also more complicated and
heavier, so it isn't necessarily superior, depending on what you want to
do with it.


It wouldn't have to be heavier; the complete Soyuz with its equipment
module came in at around the same weight as the Apollo CM due to its
layout allowing the use of a considerably smaller diameter heatshield.
It also had superior internal volume between its orbital and descent
modules to the Apollo CM.



(Arguably the right way to do a return to the Moon is to design the
vehicle for economical resupply of a lunar base -- which would favor
reusability even at the expense of greater weight and complexity -- and
accept that it would be suboptimal for short preliminary visits.



You know where this concept ends up, don't you?:
http://vesuvius.jsc.nasa.gov/er/seh/collier4.gif ;-)

Pat

In article ,
Pat Flannery wrote:
The GE/Soyuz design is more versatile, but it's also more complicated and
heavier, so it isn't necessarily superior, depending on what you want to
do with it.

It wouldn't have to be heavier; the complete Soyuz with its equipment
module came in at around the same weight as the Apollo CM due to its
layout allowing the use of a considerably smaller diameter heatshield.

Other things being equal, it generally ends up heavier, because various
subsystems are duplicated between the orbital and descent modules, and the
ability to separate half the spacecraft imposes penalties in the joint
between the halves. But other things are not equal for comparing Apollo
and Soyuz.

The heatshield isn't a big mass problem, and in this case the difference
there is exaggerated because Apollo's heatshield is (a) designed for lunar
reentry, and (b) grossly overbuilt because its specs had to be fixed
before the scaling laws were fully understood.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

Pat Flannery wrote:
[...]
You know where this concept ends up, don't you?:
http://vesuvius.jsc.nasa.gov/er/seh/collier4.gif ;-)

Some of the lander drawings shown so far look a lot like that turned
sideways.

/dps

On Thu, 19 Jan 2006 00:27:24 GMT, (Henry Spencer)
wrote:

In article ,
Pat Flannery wrote:
The GE/Soyuz design is more versatile, but it's also more complicated and
heavier, so it isn't necessarily superior, depending on what you want to
do with it.

It wouldn't have to be heavier; the complete Soyuz with its equipment
module came in at around the same weight as the Apollo CM due to its
layout allowing the use of a considerably smaller diameter heatshield.

Other things being equal, it generally ends up heavier, because various
subsystems are duplicated between the orbital and descent modules, and the
ability to separate half the spacecraft imposes penalties in the joint
between the halves. But other things are not equal for comparing Apollo
and Soyuz.

The heatshield isn't a big mass problem, and in this case the difference
there is exaggerated because Apollo's heatshield is (a) designed for lunar
reentry, and (b) grossly overbuilt because its specs had to be fixed
before the scaling laws were fully understood.

I haven't seen any articles on what the CEV's heat shield will be,
updated Apollo or a version of the shuttle technology.
Won't the CEV be making a lunar and even mars reentry profile, or are
the mission profiles including a return to the ISS or orbit before
descent? Or are they planning to make the heat shield specific for
each mission, one for LEO, and others for lunar and beyond?


Seagull

Henry Spencer wrote:
In article ,
Pat Flannery wrote:
The GE/Soyuz design is more versatile, but it's also more complicated and
heavier, so it isn't necessarily superior, depending on what you want to
do with it.

It wouldn't have to be heavier; the complete Soyuz with its equipment
module came in at around the same weight as the Apollo CM due to its
layout allowing the use of a considerably smaller diameter heatshield.

Other things being equal, it generally ends up heavier, because various
subsystems are duplicated between the orbital and descent modules, and the
ability to separate half the spacecraft imposes penalties in the joint
between the halves. But other things are not equal for comparing Apollo
and Soyuz.



Soyuz was a good solution for the constrained booster diameter they
were working with. A single module would have been painfully cramped.
But their two other designs, TKS and Zarya, with a wider base for the
capsule, both had a single manned module.

Will McLean

In article ,
Seagull wrote:
I haven't seen any articles on what the CEV's heat shield will be,
updated Apollo or a version of the shuttle technology.

Likely it will be an ablator, an updated version of Apollo's. The shuttle
tiles don't deal well with the short sharp reentry of a capsule, and they
probably can't handle the extra-severe heating environment of a beyond-LEO
reentry either.

Won't the CEV be making a lunar and even mars reentry profile, or are
the mission profiles including a return to the ISS or orbit before
descent? Or are they planning to make the heat shield specific for
each mission, one for LEO, and others for lunar and beyond?

A return to orbit is basically impractical. But the lunar and Mars
versions of CEV are well off in the future, so different heatshield
designs are a distinct possibility.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

On Fri, 20 Jan 2006 05:48:33 GMT, (Henry Spencer)
wrote:

A return to orbit is basically impractical.

....Henry, clarify this one, if you would.

OM
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Henry Spencer wrote:

The heatshield isn't a big mass problem, and in this case the difference
there is exaggerated because Apollo's heatshield is (a) designed for lunar
reentry, and (b) grossly overbuilt because its specs had to be fixed
before the scaling laws were fully understood.


The Zond heatshield didn't weigh all that much more than the standard
Soyuz one- Zond's descent capsule weighed 2,800 kg.; Soyuz's (7K-OK, the
early version) weighed in at 2,810 kg. Weight was saved by the removal
of the reserve parachute and the third crewman.
The hatch cover over the reserve parachute compartment was replaced with
a entry hatch for the crew, as in this case there was no orbital module
attached to the top of the descent module to enter via, as in the normal
Soyuz.
And here's something I didn't know- in case of failure of the main chute
after reentry, the two man Zond crew could jettison the entry hatch and
bail out of the capsule using parachutes. Shades of the shuttle escape
pole!
I assume the very long distance aerodynamic skip maneuver on reentry
also saved mass in the heatshield by letting it cool somewhat between
its first and second contact with the atmosphere.
Weight of the descent capsule for the planned manned Lunar landing
7K-LOK Soyuz variant is quoted as 2,804 kg.
(all figures from Encyclopedia Astronautica)

Pat