Project Constellation Questions

(Alex Terrell) wrote in message . com...

My idea would be purchase batches of 12 launches every 2 years. After
competion, that makes for a 1.5 billion contract coming up every 2
years. That gives a reason to get the cost down immediately for
boeing, LM, Arianne, and something to aim for for SpaceX, Kistler and
others.

that makes a lot more sense. it sounded like you thought 12 launches
every two years total was enough to cause vigorous competition.

Tom Merkle

In article ,
Edward Wright wrote:
Double that. It would take 5-6 EELV Heavy launches
to perform a single lunar mission,

It *could* take that many, but it could be done with less also. Lunar
Gemini would have required two launches -- and the launchers they
proposed were smaller than Delta IV Heavy.

The only lunar mission that Lunar Gemini *definitely* could have performed
with two launches was a free-return flyby -- not even lunar orbit, much
less landing.

When I break down typical lunar mission designs into
launchable components, I find that a launcher in
the 27-30 ton to LEO class would be about right.

What do you consider a "typical" lunar mission, and what can't be
disassembled down into components smaller than 27-30 tons?

If we take the Apollo/Saturn design as nominal -- not because it is
necessarily optimal, but just as a reference point with well-established
mass numbers from actual hardware (as opposed to viewgraphs) -- the
heaviest single lump was the S-IVB stage, dry, at about 17t. If you plan
to fuel it in orbit, you probably want to go with some sort of modular
tankage, which will increase the overall dry mass but reduce the mass of
the base unit a little bit. (The performance hit from the extra dry mass
can be recovered by draining one tank module at a time and jettisoning the
empties immediately.)

Given modular tanks for everything except the LM ascent stage (where dry
mass is particularly critical), 15t is plenty. That's enough for the
TLI-stage base unit, and for the LM with the ascent stage already fueled.
The SM goes up with one not-quite-full tank module, and gets another
added. The LM descent stage gets a tank module added. The TLI stage gets
four LOX/LH2 tank modules, or a somewhat larger number for storables. And
the CM goes up with the crew.

You can go somewhat lower without significant changes to anything except
the TLI stage. 10t ought to be straightforward.

You can go *much* lower if you're willing to accept somewhat higher dry
masses and get rather more aggressive about orbital assembly. But 10-15t
is plenty for a scheme that does nothing but plug modules together, which
we have already done and can certainly do again.

The largest
one I can think of is a human being, and they're more in the range of
0.1 tons.

They're more like 0.3-0.5t by the time you add life support and safety
equipment, although in a reusable launcher in particular, some of that
might not count against payload mass.

However, it's a *lot* of trouble to put together a lunar spacecraft from
pieces of that size. Not impossible, but a big job for orbital assembly.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

(Space Cadet) wrote in message om...
I've heard that the first Unmanned flight of the Project
Constellation/CEV might occur as earily as '07 or '08, but it won't
become operational til '14.
Are they talking about the full Lunar Version being operational by
then? Surely it shouldn't take that long to develop the LEO version,
should it? All we are talking about is a new & improved version of
the Apollo CSM. How long did it take to develop the original Apollo?
Of course we aren't under the same time limit then as now, but it
shouldn't need to take 6-7 years to develop?

Comments anyone?

Space Cadet


Well between AS201 and Apollo 6 , it was only about 2 years 1966 to
1968 to test the Command and Service Module ...un-manned.
But that was Apollo.
However , seems it should not take all that much time to man-rate a
Delta,
or Atlas or even an Ariane...
So if the resources were applied it is possible the Constellation
could be
LEO by 2010, modulo about a whole bunch of stuff.

(Edward Wright) wrote in message . com...
(ed kyle) wrote in message . com...

A half descent moon program would require about 12 Delta IV Heavies
(20-25 tons to LEO) every 2 years. (This would be in addition to
USAF,
commercial and ISS launches).

Double that. It would take 5-6 EELV Heavy launches
to perform a single lunar mission,

It *could* take that many, but it could be done with less also. Lunar
Gemini would have required two launches -- and the launchers they
proposed were smaller than Delta IV Heavy.
What do you consider a "typical" lunar mission, and what can't be
disassembled down into components smaller than 27-30 tons?


An Apollo-class mission seems "typical" to me, because it
only makes sense for NASA to use Apollo as the prototype for
the next lunar program. LOR works, it provides an extra
margin of proven safety above other approaches, and it
minimizes LEO mass.

The final Apollo missions required nearly 138 metric tons
in LEO to boost the 45.3 ton CSM/LM stack toward the moon.
The stack weighed about 33.8 tons in lunar orbit. Apollo's
15 ton LM weighed something more than 6 tons after it landed.

It takes more than five 25-ton payload launches to put 138
tons into LEO. Today, LEO mass could be reduced for an
Apollo-equivalent mission in several ways, as follows.

1. Use TLI engines with higher ISP than J-2. This could
cut the TLI mass-ratio from 2.14 to 2.03, and the LEO
mass down to 126 tons.

2. Use cryogenic fuels for lunar orbit insertion. This
could cut the LOI mass-ratio from 1.34 to 1.23 and trim
the LEO mass down to 119 tons.

3. Use cryo fuels for lunar landing too. This could cut
the lunar landing mass-ration from 1.92 to 1.57, cutting
LM mass down to 12 tons and LEO mass down to 112 tons.

4. Take a couple of tons out of the overbuilt Apollo CSM
design. This could reduce LEO mass, assuming all of the
above steps are taken, down to 108 tons.

Even with this approach, more than four 25-ton LEO launches
are still needed. A 27 ton LEO launcher could do the 108 ton
mission with only four launches.

LEO mass *could* drop below 100 tons if a riskier, direct
ascent approach were used that combined LM and SM hardware
into a single machine. A bare-bones version of this might
need as few as three EELV-Heavy launches, but safety
margins would be shaved considerably.


Assuming NASA uses EELV at all. From last week's Space News, it
appears Adm. Steigle has already decided he wants to develop a heavy
lift vehicle, either Shuttle-C or an entirely new desing.


A bigger booster would simplify mission planning and
would solve the problem of too-few EELV pads (by reusing
existing shuttle pads, presumably). This does not have
to preclude CEV flying on EELV too, for LEO/ISS missions.

- Ed Kyle

ed kyle wrote:
(Alex Terrell) wrote:
A half descent moon program would require about 12 Delta IV Heavies
(20-25 tons to LEO) every 2 years. (This would be in addition to USAF,
commercial and ISS launches).

Double that. It would take 5-6 EELV Heavy launches
to perform a single lunar mission,

This is not strictly true. I have at least two identified
mission architectures which can fly one astronaut to the moon,
land them, and return them to Earth on a single EELV payload
(even Atlas V 551, not just Delta-IVH). One of them is an
evolved Lunar Millennium, the other one is a different
optimization but similar in some ways.

The question of what good is a single astronaut, with a few days
supplies and a Lunar Rover, is a valid question. But I
presume we could land near a base and stay longer and operate
longer as well.

Throwing mass at problems is not always the right option.


-george william herbert

(George William Herbert) wrote in message ...
ed kyle wrote:
(Alex Terrell) wrote:
A half descent moon program would require about 12 Delta IV Heavies
(20-25 tons to LEO) every 2 years. (This would be in addition to USAF,
commercial and ISS launches).

Double that. It would take 5-6 EELV Heavy launches
to perform a single lunar mission,

This is not strictly true. I have at least two identified
mission architectures which can fly one astronaut to the moon,
land them, and return them to Earth on a single EELV payload
(even Atlas V 551, not just Delta-IVH). One of them is an
evolved Lunar Millennium, the other one is a different
optimization but similar in some ways.

Yes. You can send a single astronaut to the moon in a single EELV
launch after spending about $1.5 to $2.0 billion on payload hardware.


The question of what good is a single astronaut, with a few days
supplies and a Lunar Rover, is a valid question.

The same hardware can be adapted to unmanned one way flights. That
means you can pre-position lots more payload for extended stays with
enough equipment to do serious science.

Ask this question, what good are a dozen astronauts spending a year on
the moon? That's a valid question too!

Imagine a moon program where there are two EELV launches per month -
one with a single astronaut, one with a one way supply capsule.
Imagine a stay time of twelve months.

This is a way given this mission profile, a dozen scientists can be
operating continuously on the moon - either together at a single site,
moonbase fashion, or spread across the lunar landscape in a number of
smaller more interesting sites. Rocket belts that burn the same
propellant as the return engines could provide emergency long range
transport between sites.

With communications delay in the two second range its also possible to
consider augmenting astronauts on the scene with rovers, instruments,
etc., to increase their range of operations.

A mix of automated systems tended by an astronaut on-site has a lot to
recommend it.


There are also business models like that of Lunacorp - where you send
lunar rovers that can be driven by folks on the ground for a fee. You
can also send and receive keepsakes from the lunar surface if you send
even modest payloads back and forth. I don't think any of this can do
the heavy lifting of making the program pay, but it can defer some
costs at very little risk and involve the private sector.

Then there is the Zubrin idea of using local resources to make
propellants. THis could be done on the moon as well as mars. But on
the moon we get oxygen from the soil.

If this can be done, we can send larger manned vehicles on our small
launchers and increase the amounts of equipment per dollar we send to
the moon - increasing our presence there.

But I
presume we could land near a base and stay longer and operate
longer as well.

As I said, you could send 12 months supplies one way by adapting the
manned harware to an unmanned supply capsule. So, in two launches you
could have a long-term presence. A series of launches over the course
of a year could in a few years build a substantial base.

Throwing mass at problems is not always the right option.


That's right. The central figure of merit is cost per kg-km/sec.
Invest to lower this figure and what you can do in a given budget
increases.

-george william herbert


William Mook

(Edward Wright) writes:

Assuming NASA uses EELV at all. From last week's Space News, it
appears Adm. Steigle has already decided he wants to develop a heavy
lift vehicle, either Shuttle-C or an entirely new desing.

Given his position, would you really expect he propose anything other
than a shuttle derived vehicle? He'll certainly lobby hard for such a
vehicle, but that lobbying would be as much self preservation (and
preservation of all of the people he manages) than anything else.

Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.

jeff findley wrote in message ...

Assuming NASA uses EELV at all. From last week's Space News, it
appears Adm. Steigle has already decided he wants to develop a heavy
lift vehicle, either Shuttle-C or an entirely new design.

Given his position, would you really expect he propose anything other
than a shuttle derived vehicle? He'll certainly lobby hard for such a
vehicle, but that lobbying would be as much self preservation (and
preservation of all of the people he manages) than anything else.

Since he just came from DoD, I would have expected him to share DoD's
fascination with EELV, rather than NASA's fascination with Shuttle and
Saturn.

If he's been captured by the bureaucracy after less than a month on
the job, what's going to happen after a year... or a decade?

(George William Herbert) wrote in message ...

The question of what good is a single astronaut, with a few days
supplies and a Lunar Rover, is a valid question.

Right now, NASA is planning to spend $1.3 billion to send an automated
rover and no astronauts. One would be a considerable improvement.

(ed kyle) wrote in message . com...

An Apollo-class mission seems "typical" to me, because it
only makes sense for NASA to use Apollo as the prototype for
the next lunar program.

By the same logic, the prototype for a typical transatlantic flight
would be a single-engine airplane overloaded with fuel. Just because
you did something once doesn't mean you should do it that way all the
time.

LOR works, it provides an extra
margin of proven safety above other approaches, and it
minimizes LEO mass.

Why do space types always think the goal is to minimize launch mass?
In any other transportation industry, people seek to minimize cost,
not launch mass.

The "extra margin of proven safety" is proven by only a single data
point. Sure, if you happen to have a lunar module along, you can use
it as a lifeboat. However, there are other ways of adding redundancy.
LOR also introduces an additional failure mode. If there had been just
one more Apollo mission, there might have been an LOR failure, and
people would now talk about LOR not as a proven safety margin by as a
proven risk factor, the same way George Herbert talks about winged
spacecraft. As someone (Henry?) said recently, if a single data point
can change your conclusion, you don't have valid statistics.

Even with this approach, more than four 25-ton LEO launches
are still needed. A 27 ton LEO launcher could do the 108 ton
mission with only four launches.

So? Why are four launches intrinsically better than five?

A bigger booster would simplify mission planning and
would solve the problem of too-few EELV pads (by reusing
existing shuttle pads, presumably).

So, instead of remodelling the existing Shuttle pads for EELV, you
would remodel them for Yet Another Expensive Launch Vehicle? How does
that make any sense?

You aren't "simplifying mission planning," either, unless you ignore
the huge amount of planning needed to develop YAELV.

This does not have to preclude CEV flying on EELV too, for LEO/ISS missions.

Meaning, NASA would never keep its promise to finally buy commercial
launches to LEO/ISS. Why is that a good thing?