Lunar Lander in a 5.2m faring?

In message
Fred J. McCall wrote:

"Jeff Findley" wrote:

Why do the feed lines have to be high pressure?

How does the fuel get into the engine? Little tiny men with buckets?

Pumps that come /after/ the connectors?

Anthony

In article ,
Fred J. McCall wrote:
:Maybe, but the simplest solution would be to launch the lander without
:any fuel tanks first, and then attach fuel tanks...

And you're back to talking about assembly of pressure fittings in
space. This is almost always a bad idea, particularly for relatively
high pressure fittings like fuel feed lines.

The Russians made it work quite routinely -- untouched by human hands --
for refueling Mir (and, I believe, ISS) from Progress tankers. There's
nothing that hard about it.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

(Henry Spencer) wrote:

:In article ,
:Fred J. McCall wrote:
::Maybe, but the simplest solution would be to launch the lander without
::any fuel tanks first, and then attach fuel tanks...
:
:And you're back to talking about assembly of pressure fittings in
:space. This is almost always a bad idea, particularly for relatively
:high pressure fittings like fuel feed lines.
:
:The Russians made it work quite routinely -- untouched by human hands --
:for refueling Mir (and, I believe, ISS) from Progress tankers. There's
:nothing that hard about it.

Depends on what your fuels are and how you get them to the engines.
So what you're proposing are gas-pressurized hypergolic fuel engines
with (relatively) low thrust?

ISS main engines, for example, only develop around 100 lbs of thrust
apiece. Mir engines are significantly larger, getting all the way up
around 650 lbs of thrust each.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

In article ,
Fred J. McCall wrote:
:The Russians made it work quite routinely -- untouched by human hands --
:for refueling Mir (and, I believe, ISS) from Progress tankers. There's
:nothing that hard about it.

Depends on what your fuels are and how you get them to the engines.
So what you're proposing are gas-pressurized hypergolic fuel engines
with (relatively) low thrust?

Not necessarily.

Making the pipe bigger, to feed higher-thrust engines, poses no
fundamental problems, especially since (unlike ISS/Mir) there is no
particular need to be able to break the connection again once it's made.

As others have noted, essentially all rockets are gas-pressurized for the
feed from the tank to the engine, and not at high pressures either. The
Saturn V first stage, with engines devouring over 13 tons of fuel per
second, ran its fuel tank at about 25psi and its LOX tank at about 20psi.
All the high-pressure stuff is on the engine.

And there's no particular reason why hypergolics are magic in this
connection -- if anything, it's easier with non-hypergolics, because
they aren't as corrosive.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

But how can you get a descent lunar lander, capable of landing ~10 tons
on the lunar surface, into the 5.2m dimater faring offered by SpaceX
(or Boeing, LM, or the Stick)?

Can this be done without orbital assembley?

Sure. Why not. 5m diameter is plenty if you do not use hydrogen. Two 4m
diameter spheres filled with liquid methane and LOX would contain more
than enough fuel to land and launch quite a large payload on the moon.
You would just have to fill it up at a propellant depot in low earth
orbit.

One idea I had would be a lander that consists of two propulsion units
that would fit either side of the payload, and would be joined across
the top by a "bridge". The payload would fit in the middle, suspended
from the joining bridge. This bridge would be telescopic, enabling the
two propulsion units to be launched together inside a single faring.

I don't think that would be necessary. I like the skycrane approach
that is now proposed for advanced mars missions:
http://www.space.com/images/h_msl-skcrane_schema_02.jpg. Something
like this should work even better in the lower gravity of the moon.

Rüdiger Klaehn wrote:
But how can you get a descent lunar lander, capable of landing ~10 tons
on the lunar surface, into the 5.2m dimater faring offered by SpaceX
(or Boeing, LM, or the Stick)?

Can this be done without orbital assembley?


Sure. Why not. 5m diameter is plenty if you do not use hydrogen. Two 4m
diameter spheres filled with liquid methane and LOX would contain more
than enough fuel to land and launch quite a large payload on the moon.
You would just have to fill it up at a propellant depot in low earth
orbit.


You also have the Transhab concept, which would also allow for the
volume contraints for the manned portion.

For that matter, I think you might also be able to manage a similar
form of inflatable tankage. There is no rule that the tankage has to
be metallic. There are several bladder systems that would work fairly
well.

You also have the Transhab concept, which would also allow for the
volume contraints for the manned portion.

That would definitely be a good idea for the manned portion. If people
are supposed to live and work on the moon for several weeks to months,
they will need some room. But the manned portion would be a separate
module.

For that matter, I think you might also be able to manage a similar
form of inflatable tankage. There is no rule that the tankage has to
be metallic. There are several bladder systems that would work fairly
well.
Of course you could do this. But it is not necessary for the first
mission since 5m diameter is more than enough to store lots of
propellant.

Might be a good idea for an orbital propellant depot though: Two
bigelow 330 modules adapted to propellant storage could store more than
100 metric tons of liquid methane and more than 300 metric tons of
liquid oxygen. That should be enough for several very ambitious moon
missions.

And with such a large diameter, an almost spherical shape and many
debris protection layers, boiloff should be minimal.

Charles Buckley wrote:
Rüdiger Klaehn wrote:
But how can you get a descent lunar lander, capable of landing ~10 tons
on the lunar surface, into the 5.2m dimater faring offered by SpaceX
(or Boeing, LM, or the Stick)?

Can this be done without orbital assembley?


Sure. Why not. 5m diameter is plenty if you do not use hydrogen. Two 4m
diameter spheres filled with liquid methane and LOX would contain more
than enough fuel to land and launch quite a large payload on the moon.
You would just have to fill it up at a propellant depot in low earth
orbit.


OK - so we have 2m of engine and 8m length of tankage, and the cargo is
now at 10m.

Whilst I beleive that LOX / Kerosene is the best propellant choice for
Earth launch and perhaps the EDS, I think LOX/LH2 is better for lunar
operations, because (OK, if) H2 and O2 can be obtained from the moon.

That's obviously why NASA's gone for methane!

You also have the Transhab concept, which would also allow for the
volume contraints for the manned portion.

Yes, but your transhab is now sitting at 10m above the lunar surface.

For that matter, I think you might also be able to manage a similar
form of inflatable tankage. There is no rule that the tankage has to
be metallic. There are several bladder systems that would work fairly
well.

Would propellant sloshing be a problem?

Alex Terrell and to all others of this topic,
Why are you folks having to re-invent the fly-by-rocket wheel?
Obviously the entire NASA/Apollo fiasco isn't working out, now is it?

Personally I see nothing all that insurmountable about multiple
assemblies transpiring safely and efficiently in space. Haven't these
negative about everything fools ever heard of CAD engineering that's
been more than capable for creating end-results that are good to less
than 0.001", and of the "O ring" that can manage quite nicely with as
great as +/- 0.1"?

Even the tapered metal to metal joints, as in male tapered flange to
female tapered flange of non-O-ring methods is self aligning. So what
exactly is "Fred J. McCall" yapping about?

How Rockets Differ From Jets
http://groups.google.com/group/sci.s...107473b791e711
Engineering ain't magic, Tomcat.
This analogy should apply to many that claim that w/o documented
engineering that we've managed to fly-by-rocket lande upon and
EVA/moonsuit walked upon the moon, while forgetting six times out of
six to honestly photograph anything, forgetting to bring back any of
that extremely thin, colorless and highly retro-reflective layer of
"magic" clumping moon-dust, and even 6 times out of 6 expeditions
forgetting to bring back any moon atmospheric samples which should have
been loaded with the likes of sodium, radon and argon, as well as a
touch of O2 and dozens of other viable elements to boot. Christ
almighty, MESSENGER can't even include an honest look-see at the
natural dark colour of our own moon in their Earth flyby. Is all of
this MOS pathetic engineering magic or what?
~

Kurt Vonnegut would have to agree; WAR is WAR, thus "in war there are
no rules" - In fact, war has been the very reason of having to deal
with the likes of others that haven't been playing by whatever rules,
such as GW Bush.
Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac:
http://guthvenus.tripod.com/gv-town.htm
The Russian/China LSE-CM/ISS (Lunar Space Elevator)
http://guthvenus.tripod.com/lunar-space-elevator.htm
Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS
http://guthvenus.tripod.com/gv-topics.htm

On 23 Oct 2005 03:56:21 -0700, "Alex Terrell"
wrote, in part:

But how can you get a descent lunar lander, capable of landing ~10 tons
on the lunar surface, into the 5.2m dimater faring offered by SpaceX
(or Boeing, LM, or the Stick)?

A lunar lander with 8,650 pounds empty weight and 32,500 pounds weight
of crew and propellant (that is, pounds of mass, or weight in Earth's
gravity) or a mass of 10,149 kilograms in the descent stage, and 4,547
kilograms in the ascent stage...

is alleged to have been sent to the Moon within a fairing 21 feet and 8
inches in diameter.

Ah, but that is 6.6 meters, so indeed a narrower fairing is being
proposed. And the mission is proposed to put four astronauts on the
lunar surface, so something bigger than the Apollo Lunar Module is
required - and the pictures being presented do show something which is
clearly quite a bit larger than the LM.

I don't see this as an insuperable obstacle, since a spaceship can be
made tall and narrow; it doesn't have to look like the Lunar Module,
having a round crew module, and a short base.

John Savard
http://home.ecn.ab.ca/~jsavard/index.html
http://www.quadibloc.com/index.html
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