Dave O'Neill dave @ NOSPAM atomicrazor . com wrote:
"George William Herbert" wrote:
Dave O'Neill dave @ NOSPAM atomicrazor . com wrote:
A Proton/Ariane5/etc... size launcher can soft land around 6,000kg
of cargo on the surface at a reasonable cost for supply purposes.

Six tons?

Could you document that and/or provide numbers?

I've been working on lunar missions for some time and get
payloads around three tons off a Proton, A5, D-IV etc.

Checking on The Encylopedia, the last sample return mission massed 5,800kg's
and was launched using the Proton. I didn't do the sums myself but a
collegue did them and was pretty sure you could manage things with a Proton.

I could see if I kept the numbers if you want. They were sketchy though, we
were looking at a proof of concept, and frankly, we couldn't make the
numbers add up even with 6 tonnes.

Just off the top of my head... that is the right mass for the
Proton payload delivered to Lunar Transfer Orbit, not landed mass.

If that 5,800 kilos includes the lunar orbit insertion and landing
fuel then sure. But there are several km/s worth of delta-V required
to go from LTO to lunar surface.

There are a couple of general approaches for how to do a modern lander
with an existing launcher.

One is to fit it into the LTO payload of an existing LV and have the
'payload' include the lander stage and all, and any required ascent
stage.

What I was proposing with Lunar Millennium was to launch a fully
fueled centaur-like stage to LEO, and use that for TLI, LOI,
and most of landing delta-V, but then drop that at a low
altitude above the lunar surface and do the final landing with
a minimal descent stage for the final few hundred meters / km.
Among other things, that minimizes the payload's propulsion
requirements for a one way mission, and for a two way mission
can efficiently let the lander and return / ascent vehicle be
the same vehicle, without having to stage on liftoff.

When I worked the numbers, and I did it a bunch in the mid-90s,
I consistently got around 3 tons down either way, but a lot
less components and in particular a lot less *new development*
components the LM way.


-george william herbert