Capsule for new space initiative

Charles Buckley:
Anvil wrote:
What should be reused from Apollo is the outer shape of the capsule
and it's associated aero-thermodynamic data.

*snip*
Even if they reuse the Apollo shape and config, there is enough
of an argument that there will be a radically different density
variation that the thermal loading figures might be off by quite a
bit.

IIRC, thermal loading is a combination of aspect ratio and
wing loading. With wing loading being the greater portion of the
equation. You change the density of the capsule by using lightweight
materials and shrinking the avionics systems and you are essentially
designing a new thermal environment that would have to be analysed
from scratch.
-----
The shape was developed using mathematical models, small physical
models in a plasma wind tunnel, and empirical data gathered from
flights. The shape and it's properties are very much like selecting
an airfoil shape for a wing. It has coefficients of lift and drag
along with properties specific to ballistic reentry. Still I would
like to keep about the same size and weight but a size change is
within college level design study scale. My worry is that even with
lighter weight materials and avionics the tendency will be a heavier
capsule.

So what to do. Someone will have to play the part of a goal tender and
fend off add-ons and what-ifs. Another items that should be considered,
but are contrary to space launch systems is leaving instrumentation and
panel space for the future and carrying ballast. That last one will go
over well, but planning from the start to have a weigh margin and a
simple method to adjust the center of gravity is prudent. One team will
come out lighter than expected another will be heavy but they will be
on opposite sides of the balance.

Next lets publish our capsule as a standard. Shape, weight range, cg
location, all connections and physical interfaces, voltages and power
available, radio frequencies and telemetry signals... It is
unrealistic to assume another country would build a compatible capsule
or module in the near future, however it is best to start early, build,
and rebuild any standard (assuming space faring is in our future).

Nick Maclaren:
A mere year's delay and factor of 3 overrun is pretty good under
those conditions - there are lots of examples that have been much
worse ....

-----
Agreed, but I am lucky to be in established industry. Space related
start-ups are marginally funded buy investors who are not infinitely
patient. They are lucky if they get funding, much less one shot with
one customer. Missing your launch date and running out of cash by
first one-third of your program adds you to the list of where are
they now (interesting technology never developed).

The question might be: If they knew, it would take five more years
and cost four times what they thought on their first guess, would
they have been able to attract investors? customers?

Abrigon Gusiq wrote:


I remember a "joke" once, that if the Wright brothers had done their
famous flight today, it would never have gotten of the ground, due to
OSHA/EPA, and other regulations.
As well as enviromental and other fun rules.. Remember they were in an
area with alot of birds, some likely indangered.. As well as to ask for
someone other than one of the brothers to fly it, if the pilot died, the
family might sue.


The inspiration for this might of been a short story Mark Twain wrote
about a German shipping inspector getting a look at Noah's Ark, which
broke more than a few regulations.

Pat

(Henry Spencer) wrote in message
They do... but almost nothing in Apollo is a reasonable way to do things
any more. We'd have to re-engineer almost everything anyway, because
while the plans are still around, the tooling is gone and the experienced
people are gone and the available components and materials have changed.
And given that we have to do that, it makes no sense to duplicate the old
subsystem designs when we can do a lot better now. Even the Apollo guys
would have done things differently if they'd had to do it again -- many
decisions made in haste turned out to be less than ideal.


Henry, do you have specific examples of somethings the Apollo guys would have
done differently?


Space Cadet

derwetzelsDASHmailATyahooDOTcom

Moon Society - St. Louis Chapter

http://www.moonsociety.org/chapters/stlouis/

The Moon Society is a non-profit educational and
scientific foundation formed to further scientific
study and development of the moon.

In article ,
Space Cadet wrote:
...Even the Apollo guys
would have done things differently if they'd had to do it again -- many
decisions made in haste turned out to be less than ideal.

Henry, do you have specific examples of somethings the Apollo guys would have
done differently?

Just off the top of my head...

The CM heatshield turned out to be grossly overbuilt. The specs were
fixed at a time when they didn't have enough data and they knew it, so
they consciously erred on the side of safety.

A slightly larger-diameter CM would have permitted better reentry L/D --
they simply didn't have enough *room* inside to offset the center of mass
as much as they'd originally intended. The CSM size was fixed based on
ideas about the diameter of Saturn upper stages which were obsolete almost
as soon as the decision was made. The rounded corner arose likewise, but
a sharp corner (like Mercury and Gemini) improves the aerodynamics
substantially.

CSM manufacturing and testing would have been greatly eased by a more
Gemini-like design approach, with removable upper-heatshield panels, and
equipment accessible from the outside rather than the inside. Apollo
repeated many of Mercury's mistakes because its basic design was fixed
before Gemini established that there was a better way.

The SM engine was sized to lift the CSM off the lunar surface, because the
mode decision wasn't final then. A redesign would have had a smaller
engine, or possibly several still-smaller ones (removing the single point
of failure).

Serious consideration would have been given to solar arrays instead of
fuel cells. Solar cells improved dramatically between the time when
Apollo's basic design was fixed and the time when it started flying.
(Soyuz, designed only a few years after Apollo, is solar-powered.)

Similarly, serious consideration would have been given to LOX/LH2
propulsion for LOI and descent (although storable fuels might have been
retained for ascent and return as a precaution). That's another
technology which looked very raw and untrustworthy in 1961 but matured
dramatically while Apollo was going from concept to flight.

More resources would have been invested in making the computer bigger
and faster, because software could replace other items of hardware.
(Some of this happened during the Block I - Block II transition, and
a redesign would have done more of it.)

Braking rockets for land touchdown would have been reconsidered. Some
work was done on them for Apollo, early on, and they have advantages.

A copy of the Skylab toilet would have been fitted. (There was a plan
to test it on Apollo 14, in fact, but Shepard vetoed it.) The Apollo
baggies simply did not work terribly well, resulting in a lot of wasted
time and less-than-ideal sanitation, especially when somebody was ill.

The LM landing gear was another overdesigned piece of gear, thanks to
uncertainties about both the lunar surface and the astronauts' ability
to fly to a gentle touchdown.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |