Lunar Lander in a 5.2m faring?

"Jeff Findley" wrote:

:
:"Fred J. McCall" wrote in message
.. .
: Brian Thorn wrote:
:
: :On 23 Oct 2005 03:56:21 -0700, "Alex Terrell"
: :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?
: :
: :Maybe, but the simplest solution would be to launch the lander without
: :any fuel tanks first, and then attach fuel tanks (launched seperately
: r uninstalled on the same launcher.) in orbit. That would take some
: :ISS-like assembly, though.
:
: 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.
:
: Space assembly is HARD, people. It's difficult and clumsy work.
:
:Why do the feed lines have to be high pressure?

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

:Why not have a single set
f high pressure tanks on the "core" of your stage, and attach lower
ressure fuel and oxidizer tanks to that? This means you'd have to do a
:series of burns to get where you're trying to go, but it might make the task
:easier by eliminating those high pressure connections.

Any task that reduces vehicle capability (as your suggestion above
does) no doubt makes things easier.

:The Russians have been transferring storable hypergolic fuel and oxidizer
:from Progress tankers to their stations (including ISS) for years. No EVA
r clumsy pressure fittings seem to be required for this to work.

Now you might want to look at the thrust developed and burn durations.
I don't see any of those vehicles going to the Moon, landing, and then
taking back off.

--
"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

"Fred J. McCall" wrote in message
...
"Jeff Findley" wrote:
:The Russians have been transferring storable hypergolic fuel and oxidizer
:from Progress tankers to their stations (including ISS) for years. No
EVA
r clumsy pressure fittings seem to be required for this to work.

Now you might want to look at the thrust developed and burn durations.
I don't see any of those vehicles going to the Moon, landing, and then
taking back off.

Which is why I've said before that I think in orbit transfer of LOX and
other mild cryogens (like methane) ought to be a technology that NASA should
be researching now. After all, once we set our sights on Mars, even the
SDHLV is going to be too small to launch a fully fueled Mars transfer stage.
Why not start working on the technology needed now?

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

Fred J. McCall wrote:

[snip]
:The Russians have been transferring storable hypergolic fuel and oxidizer
:from Progress tankers to their stations (including ISS) for years. No EVA
r clumsy pressure fittings seem to be required for this to work.

Now you might want to look at the thrust developed and burn durations.
I don't see any of those vehicles going to the Moon, landing, and then
taking back off.

So let me get this straight:

scaling up from the several hundred kgs the russian progress routinely
transfers to the ISS http://www.russianspaceweb.com/progress.html to
the tens of tons required for a lunar mission is so complex that it
can't be possibly be finished until 2018.

But building a huge heavy lift vehicle out of shuttle components has
negible technological risk?

Orbital propellant transfer of storable propellants and even mild
cryogens such as liquid oxygen and liquid methane is not that hard.
There are even materials which remain flexible at liquid oxygen
temperatures, so you could use a simple bladder system. It is just that
nobody has ever seriously tried to do it.

Rüdiger Klaehn wrote:
Fred J. McCall wrote:

[snip]
:The Russians have been transferring storable hypergolic fuel and oxidizer
:from Progress tankers to their stations (including ISS) for years. NoEVA
r clumsy pressure fittings seem to be required for this to work.

Now you might want to look at the thrust developed and burn durations.
I don't see any of those vehicles going to the Moon, landing, and then
taking back off.

So let me get this straight:

scaling up from the several hundred kgs the russian progress routinely
transfers to the ISS http://www.russianspaceweb.com/progress.html to
the tens of tons required for a lunar mission is so complex that it
can't be possibly be finished until 2018.
No. The only reason for the current envisioned delay to 2018 is to
allow a funding delay in developing a SDHLV due to the perceived need
to continue funding shuttle until 2010.


But building a huge heavy lift vehicle out of shuttle components has
negible technological risk?

negligable on-orbit technical risk, especially compared to on-orbit
assembly and fuel transfer operations. If shuttle and ISS have proved
one thing, it's that on-orbit technical risk should be traded for
ground technical risk wherever possible.


Orbital propellant transfer of storable propellants and even mild
cryogens such as liquid oxygen and liquid methane is not that hard.

says you.

There are even materials which remain flexible at liquid oxygen
temperatures, so you could use a simple bladder system. It is just that
nobody has ever seriously tried to do it.

Probably because it's just so simple. simple is boring... ;-)

Tom

Probably because it's just so simple. simple is boring... ;-)

Given that it is nasa we are talking about here, you might have a
point.

Remember the reasoning for picking the lockheed proposal for the x33?
They were basically arguing that the lockheed x33 required the most new
technologies and therefore would be most worthwhile to do.

The other proposals from rockwell and mcdonald douglas were too boring
for nasa, even though they might actually have flown.

"Rüdiger Klaehn" wrote:

:Fred J. McCall wrote:
:
:[snip]
: :The Russians have been transferring storable hypergolic fuel and oxidizer
: :from Progress tankers to their stations (including ISS) for years. No EVA
: r clumsy pressure fittings seem to be required for this to work.
:
: Now you might want to look at the thrust developed and burn durations.
: I don't see any of those vehicles going to the Moon, landing, and then
: taking back off.
:
:So let me get this straight:

This is almost a sure sign that someone is about to run down into the
ditch by making claims that aren't in evidence.

:scaling up from the several hundred kgs the russian progress routinely
:transfers to the ISS http://www.russianspaceweb.com/progress.html to
:the tens of tons required for a lunar mission is so complex that it
:can't be possibly be finished until 2018.

Not quite sure where I said that. I said it was not simple. If you
think just increasing the size of everything solves the problem you
are being QUITE simplistic in your analysis.

:But building a huge heavy lift vehicle out of shuttle components has
:negible technological risk?

Don't know where you think I said that, either. See what I mean about
running off into the ditch?

:Orbital propellant transfer of storable propellants and even mild
:cryogens such as liquid oxygen and liquid methane is not that hard.

For some rather large and variable value of 'that hard'.

:There are even materials which remain flexible at liquid oxygen
:temperatures, so you could use a simple bladder system. It is just that
:nobody has ever seriously tried to do it.

And usually if it's something nobody has ever tried that seems like an
'obvious' idea, there is a good reason they've never tried it.

--
"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 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

Anthony Frost wrote:

: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?

And just what makes the fuel want to go to them, again?

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn

"Fred J. McCall" wrote in message
...
Anthony Frost wrote:

: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?

And just what makes the fuel want to go to them, again?

Moderate pressure, like what you find in the ET. From the (admittedly old)
NSTS 1988 News Reference Manual, it's pressures are 20-22 psi in the O2 tank
and 32-34 psi in the H2 tank. That would seem to be enough pressure to get
LOX and LH2 moving through the 17 inch diameter feed lines.

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

In message
Fred J. McCall wrote:

Anthony Frost wrote:

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?

And just what makes the fuel want to go to them, again?

Exactly the same process as is used in every other space restartable
engine maybe? Where do you suppose the pumps for the S-IV-B J2 engine
were? You have low pressure lines for as much of the distance between
tank and combustion chamber as possible, and try and arrange the pump
output to feed almost directly into the chamber. OK, it is rocket
science, but it's pretty obvious.

Anthony