(Cris Fitch) wrote in message . com...
Not long ago it looked like the Medium lift market was
over-subscribed with Proton, Ariane-5, Sea Launch, Atlas-5
and Delta-IV.

Not to mention Zenit 2, H-IIA, and the planned heavy
lift versions of Angara and Long March 5.

Now with the retirement of Shuttle and a
new plan for manned exploration coming into being, we've
got to ask ourselves:

1) Launch lots of medium payloads
or
2) Go Heavy

I've got to argue in favor of #1, hoping that the economics
of all these medium lift launchers will reduce the overall
cost of these plans.

#1 may be needed for reasons other than economics. If
a surge of launches is required to support a single
mission, launches by more than one provider from more
than one launch site may be essential.

Proton, Angara, and land-launch Zenit are out of the
picture unless a fairly high inclination assembly orbit
is used. The mass penalties make this seem unlikely to
occur unless Russian participation is required for
political reasons.

The problem with this is that Proton has been the driver
of launch cost reduction in recent years. With it out
of the picture, launch prices would rise from current
levels. Since U.S. companies seem incapable of competing
in the commercial launch world market, Arianespace would
then, by default, get to decide how much NASA would have
to pay to launch each lunar mission.

If one feels it necessary to go for heavy lift, can't we at
least think in terms of "Delta-IV Super Heavy", such that
our flight hardware makes use of the engineering and production
already in use (and that will stay around if the politics of
heavy lift fails)?


If this work is contracted out to the lowest bidder, we
could very well see heavier-lift versions of existing
launchers offered by several companies. After all,
most of their rockets are currently optimized for GTO
not LEO, missions. LEO mass per launch would surely
rise if it improved the chances of winning launch
contracts.

Finally, there is the issue of what expertise we lose when we
shut down a heavy lift capability (Saturn V, Energia, Shuttle).
Certainly we don't mind losing the cost of the standing army,
but are we going to lose the facilities for large fuel tanks
or recoverable strap-ons?


The U.S. will lose Michoud and the SRB production
capacity, but that will be offset by the need to
have a continuous production line for mission hardware,
such as CEV, lunar landers, and the like. Shuttle
orbiter production, by comparison, was shut down a
decade ago.

Don't expect the "standing army" to disappear either.
NASA will still have to assemble, test, and integrate
the spacecraft and payloads for each mission. That
will require something on the scale of the current
ISS hardware checkout effort, except with a much
faster flow rate.

- Ed Kyle