Genesis Auger - End of Manned Capsule Worship?

(McLean1382) wrote:

. I think it's cancellation was
only partly to pay for the "Great Society." Another factor was our increasing
involvement in Viet-Nam which dried up many research efforts.

You think?

One look at comparative expenditures on Viet Nam and on Great Society
programs makes nonsense of any claim that it was the latter which
dried up funding for space (or anything else).

I think the meme survives because we all heard "If we can put men on
the moon, why can't we [solve domestic social problem X]" so many
times. Perhaps also because a sizeable fraction of space enthusiasts
had/have political views in which spending on the war was taken for
granted or approved, while spending on social programs was
discretionary if not a Bad Thing in itself.

-Monte

(McLean1382) wrote in message ...

What Boeing actually says is, "The partially completed X-20
prototype
and the mockup were scrapped, as well as initial tooling set up for
a
production line for 10 space planes."

An incomplete protype, and for what? A full up manned up orbital vehicle, or
something less than that?

Again, a 40% complete X-20 prototype does not seem to be substanially
less than a 50% complete X-38 prototype -- especially since the X-20
prototype included life-support and other systems that X-38 didn't.

The TPS was tested on unmanned Asset flights.

After they canceled the program.

Which is irrelevant. The TPS worked.

So the mass budget when they cancelled wasn't
based on any flight experience of whether the TPS woud meet expectations or
not. They flew Asset, and decided to use something else on the shuttle, so it
doesn't seem to have been entirely satisfactory.

"They" (the USAF and Boeing) didn't build the Shuttle. NASA and
Rockwell did.

I'm not aware of any suborbital test models flown in the X-38
program.

Because the X-38 deiberately used an airframe similar to X-23 and X-24 to
build on previous flight experience.

The X-38 team had no previous flight experience with X-23 and X-24.
They had data, but that's not the same thing as experience.

What does Mercury have to do with this?

The US had little experience with any of the systems for manned spacefight in
1963, so estimates of their final mass made at the time weren't very reliable.

Project Mercury has nothing to do with whether the Dyna-Soar weights
were accurate.

Experience is not a collective thing that "the US" keeps in a big box
and hands out to engineers who need it. It resides in people and
teams. When those people and teams are gone, the experience is gone.
No one on the X-38 team had development experience on Mercury, Gemini,
Apollo, or even Shuttle. In fact, Dan Goldin boasted that X-38 was an
on-the-job training program for NASA engineers.

From: (Edward Wright)
Date: 10/6/2004 2:46 PM Central Standard Time
Message-id:

(McLean1382) wrote in message
...

What Boeing actually says is, "The partially completed X-20
prototype
and the mockup were scrapped, as well as initial tooling set up for
a
production line for 10 space planes."

An incomplete protype, and for what? A full up manned up orbital vehicle,
or
something less than that?

Again, a 40% complete X-20 prototype does not seem to be substanially
less than a 50% complete X-38 prototype -- especially since the X-20
prototype included life-support and other systems that X-38 didn't.


The difference is that the X-38 program has already flown three prototypes,
and were working on #4. In addition to data from X-23 and X-24.

In 1963, the X-20 program had flown nothing. Zip. Nada. Zilch.

The TPS was tested on unmanned Asset flights.

After they canceled the program.

Which is irrelevant. The TPS worked.

In the sense that the test vehicle, which bore only a minimal resembance to the
X-20, was launched six times and recovered once. It failed to survive reentry
at least half the time.

Even a successful reentry didn't mean the heat shield worked as well as the
designers hoped. It just means it didn't kill the test vehicle.


So the mass budget when they cancelled wasn't
based on any flight experience of whether the TPS woud meet expectations or
not. They flew Asset, and decided to use something else on the shuttle, so
it
doesn't seem to have been entirely satisfactory.

"They" (the USAF and Boeing) didn't build the Shuttle. NASA and
Rockwell did.

Whatever. Boeing and the USAF have proposed ASSET. If any of them used an X-20
style TPS, I missed it.
..

I'm not aware of any suborbital test models flown in the X-38
program.

Because the X-38 deiberately used an airframe similar to X-23 and X-24 to
build on previous flight experience.

The X-38 team had no previous flight experience with X-23 and X-24.
They had data, but that's not the same thing as experience.


Whatever. The X-38 design was based on flight data from similar airframes. The
X-20 wasn't.

Wil McLean

(McLean1382) wrote in message ...

Again, a 40% complete X-20 prototype does not seem to be
substanially
less than a 50% complete X-38 prototype -- especially since the
X-20
prototype included life-support and other systems that X-38 didn't.

The difference is that the X-38 program has already flown three prototypes,
and were working on #4. In addition to data from X-23 and X-24.

If you define "flown" to mean dropped from an airplane, with
substantial damage to the test article on most drops.

In 1963, the X-20 program had flown nothing. Zip. Nada. Zilch.

If you say so. Funny thing, it was a retired engineer from the X-20
program who finally explained to NASA why X-38 wouldn't work. :-)

"Edward Wright" wrote in message
om...
(McLean1382) wrote in message
...

Again, a 40% complete X-20 prototype does not seem to be
substanially
less than a 50% complete X-38 prototype -- especially since the
X-20
prototype included life-support and other systems that X-38 didn't.

The difference is that the X-38 program has already flown three
prototypes,
and were working on #4. In addition to data from X-23 and X-24.

If you define "flown" to mean dropped from an airplane, with
substantial damage to the test article on most drops.

In 1963, the X-20 program had flown nothing. Zip. Nada. Zilch.

If you say so. Funny thing, it was a retired engineer from the X-20
program who finally explained to NASA why X-38 wouldn't work. :-)

I thought that there was an aircraft in Neil Armstrong's home town that he
originally flew as a simulator for the X-20...

Here it is, it was an F5D-1 Skylancer:

http://www.dfrc.nasa.gov/Gallery/Photo/F-5D/HTML/

This aircraft was flown to simulate launch aborts and landings. It's role
was similar to the jet aircraft NASA pilots fly to practice shuttle
landings.

That's not quite the same as the X-38 drop tests, but it is significant.

Jeff
--
Remove icky phrase from email address to get a valid address.

From: (Edward Wright)
Date: 10/7/2004 2:51 PM Central Standard Time
Message-id:

(McLean1382) wrote in message
...

Again, a 40% complete X-20 prototype does not seem to be
substanially
less than a 50% complete X-38 prototype -- especially since the
X-20
prototype included life-support and other systems that X-38 didn't.

Are you sure? The Block One Apollo capsules lacked a number of systems that
flew on the manned flights. For x-24, Spiral, Shuttle and Buran, the first
prototype wasn't a fully capable manned orbital vehicle.

The difference is that the X-38 program has already flown three
prototypes,
and were working on #4. In addition to data from X-23 and X-24.

If you define "flown" to mean dropped from an airplane, with
substantial damage to the test article on most drops.

Drop tests were planned as the first flight tests in the X-20 program. The X-38
program performed several drop tests. The X-20 program did not perform any.
Which program was closer to completion?


In 1963, the X-20 program had flown nothing. Zip. Nada. Zilch.

If you say so. Funny thing, it was a retired engineer from the X-20
program who finally explained to NASA why X-38 wouldn't work. :-)


That's nice. :-)

So, are you saying that in 1963, the X-20 program had flown flight hardware
comparable to the X-38 flight tests? Or that it hadn't, but that you would
prefer to change the subject?

Will McLean

In article ,
Pete Lynn wrote:
A quick technical question, has anyone ever considered quickly winching
the parachute in to reduce vertical landing velocity? It requires a bit
of power but might be lighter and safer than landing rockets.

It's been suggested, but it doesn't work nearly as well as you might
think. Pulling harder on the lines will rapidly accelerate the parachute
down toward you; it's *not* an elevator cable descending at a fixed rate,
which you can pull on as hard as you want without increasing its descent
rate (although you do sometimes see this error made in naive analyses).

(I assume a classical parachute, a pure drag device. A lifting parachute
like a parafoil is a more complicated animal, and permits tricks like
flare maneuvers.)

If you have, say, a 12m/s descent rate that you want to reduce to 2m/s for
touchdown, you need to double the line forces for about 1s. That means
increasing the chute's descent rate by about 40% (to get double the drag,
which scales with v^2, neglecting complications like dynamic effects of
the sudden change), to about 17m/s. And of course, you're slowing down at
the same time. Neglecting acceleration time, you need to reel in 10m of
line during that second, and you will need some acceleration time. So
you're looking at reeling in maybe 15m of line, *without* messing up the
chute's shape enough to start reducing its drag coefficient. You're going
to need long lines, rather longer than normal. Plus a fairly capable
winch system.

Another trick might be a small explosion, (fuel/air?), beneath the
parachute, (like the Medusa)...

You're reinventing the braking rocket, and probably a rather inefficient
form of it too. Complicated and would need careful analysis, but I'd be
surprised to see it looking better than well-designed rockets.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

In article ,
Greg D. Moore \(Strider\) wrote:
Somewhere around here I have Rockwell document showing how to pack
six in an Apollo.

Well for one thing, forgo the "stroke" of the center couch. This was left
in in the rescue version because they assumed they might have an injured
patient who could not survive a hard landing.

I've heard that said several times, sometimes by people who I'd have
thought would be in a position to know... but the Apollo couches, at least
in the drawings I've seen, did not *have* individual shock absorbers. The
shock absorbers attached to a frame holding all three couches. So you
*couldn't* retain shock-absorption stroke in only one couch.

The missing position in the Skylab rescue configuration held a cargo
pallet for returned film and materials, replacing the storage capacity of
some of the removed lockers. Fitting in one more couch just requires
deleting the cargo pallet.

Note that this was a rescue configuration, in which some risk was
acceptable because it would be used only in an emergency. The couch shock
absorbers were essentially unused for a splashdown; they were there for
the land-touchdown case. So for the rescue version, it was simply accepted
that coming down on land involved a high probability of injury.

There's a 12 person version I think Henry Spencer has mentioned. But I
think that's pushing it.

It would certainly have required a major redesign of the interior. And
again, that's a rescue/lifeboat configuration with no internal shock
absorption, with land touchdown very dangerous unless you add something
like braking rockets.

And a modern version could probably free up even more room.

Not much more to free up in an Apollo. :-) But do bear in mind that making
the capsule *bigger* doesn't make it much *heavier*, provided you refrain
from filling up the extra space with more equipment. Structural mass
increases only slightly, the heatshield scales with the mass not the
volume, and things like electronics don't change at all. It wouldn't be
terribly difficult to build a six-man (or probably even twelve-man) capsule
that wasn't a lot heavier than an Apollo and had full shock absorption, if
you could handle the larger diameter at launch.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Henry Spencer wrote:
In article ,
Pete Lynn wrote:

A quick technical question, has anyone ever considered quickly winching
the parachute in to reduce vertical landing velocity? It requires a bit
of power but might be lighter and safer than landing rockets.


It's been suggested, but it doesn't work nearly as well as you might
think. Pulling harder on the lines will rapidly accelerate the parachute
down toward you; it's *not* an elevator cable descending at a fixed rate,
which you can pull on as hard as you want without increasing its descent
rate (although you do sometimes see this error made in naive analyses).

(I assume a classical parachute, a pure drag device. A lifting parachute
like a parafoil is a more complicated animal, and permits tricks like
flare maneuvers.)

I propose a little thought experiment, and also for those who still
think that this is a workable idea, one that uses less added weight.
Rather than running a motor trying to climb back up the chute rope if
instead you had that 12M/s Descent rate and had a 10 meter section(zero
tension length) of bungee cord that was able to be released as slack
when the vehicle is 15 meters above the ground, the chute immediately
slows to virtually zero velocity, in about .7 seconds the vehicle is
just over 10 meters of the way towards the ground and moving nearly
20M/S then the craft starts to decelerate as the bungee cord expands
another 2.5 meters and the parachute accelerates downward to about its
terminal velocity the bungee cord then starts to contract as the craft
slows below the parachute terminal velocity of 12M/s through a distance
of 2.5meters.

Jim
If you have, say, a 12m/s descent rate that you want to reduce to 2m/s for
touchdown, you need to double the line forces for about 1s. That means
increasing the chute's descent rate by about 40% (to get double the drag,
which scales with v^2, neglecting complications like dynamic effects of
the sudden change), to about 17m/s. And of course, you're slowing down at
the same time. Neglecting acceleration time, you need to reel in 10m of
line during that second, and you will need some acceleration time. So
you're looking at reeling in maybe 15m of line, *without* messing up the
chute's shape enough to start reducing its drag coefficient. You're going
to need long lines, rather longer than normal. Plus a fairly capable
winch system.


Another trick might be a small explosion, (fuel/air?), beneath the
parachute, (like the Medusa)...


You're reinventing the braking rocket, and probably a rather inefficient
form of it too. Complicated and would need careful analysis, but I'd be
surprised to see it looking better than well-designed rockets.

"Henry Spencer" wrote in message
...
In article ,

Another trick might be a small explosion, (fuel/air?), beneath the
parachute, (like the Medusa)...

You're reinventing the braking rocket, and probably a rather
inefficient form of it too. Complicated and would need careful
analysis, but I'd be surprised to see it looking better than well-
designed rockets.

I think it could have an order of magnitude or more higher ISP.

Nice to have you back - be careful not to over do it. :-)

Pete.