On 4 May, 00:09, kT wrote:
Alex Terrell wrote:
On 3 May, 00:26, kT wrote:
I'm not totally opposed to big solids, but only for very heavy lift
launch vehicles (like the Ares V) with very low launch rates. But
clearly over the long term they have to be phased out, and the only
credible alternative is hydrogen.

Why hydrogen? Kerosene seems to be more effective. I believe for
example Atlas tends to come in cheaper than Delta.

I do believe Atlas does use hydrogen in the upper stage, feel free to
correct me if I'm wrong.

That's correct. There is a case for hydrogen in the upper stages. The
Space Shuttle Main Engines are primarily upper stage engines, in that
give most of their delta V after the SRB separation.

The other major problem is the foam
insulation, which virtually prohibits the taking of the cryogenic first
stage all the way to orbit, something which is basically trivial for a
hydrogen core stage with large solid rocket booster assistance.

There are many problems with cryogenics which effect costs.

Which explains why everybody either uses it, or wants to use it.

LOx is an attractive oxidiser. Cheap, dense, and not too cryognic.
Hydrogen is expensive, non dense and a pain.

Soyuz: Lox / Kerosene,
Proton: N2O4 / UDMH
Atlas: LOx / Kerosene lower stage
Falcon: Lox / Kerosene

Ariane is the only descent launcher to use LOx / LH2. No one else
apart from NASA is rushing to use LH2.

The *BIG* problem I have is with NASA upper management, the fraud they
have perpetrated upon the American people, by sidelining propulsion work
that is nearly finished, the RL-60 and the IPD - integrated full flow
closed cycle engine prototype, the hydrostatic bearings, and the channel
wall nozzle program, and even the SSME upgrades, the all electric nozzle
gimbles and fuel cell auxiliary power. Without those vital programs in
liquid propulsion, we have nothing. Nothing I tell you.

Agree there

All is lost.

ALL IS LOST! I am revolted.

Perhaps things just needed to get worse before they can get better.

They're demonstrably not going to get any better by continuing using
hydrocarbons and solids. It's over. The Neocene era is upon us.

Try hydrocarbons and LOx. Spacex is putting its money in to this.

You people are just complete mind****s, it's going to be so much fun
watching your lives crumble these next few years. But don't worry, great
grandchildren will be able to mine and burn coal until at least 2200,
when the planet will most likely become uninhabitable.

Yeah OK.