For example,

Start with a triple barrel Delta IV;
Add 6 GEM solid rocket boosters;
Supplement with an RL-60 upper stage;
Tweak with lithium alloy tanks;
Use slushed hydrogen and a low trajectory launch;

Okay, 45-50MT is feasible. For $200 million? Perhaps, perhaps not.

Now, take SDV which is 77MT base line (77,000 kg):

Add 5 segment SRBs;
Perhaps use four 5 segment SRBs;
Let Michoud use lithium alloy as well;
Stick an RL-60 upper stage on top of an inline SDV – – heck start with an 2x RS-68 2nd stage and go with an RL-60 THIRD stage (wink);

What if the SRBs were tweaked to include less dry mass?

Today they are 85% fuel & 15% dry mass using 1980s metallurgy. Tweak the SRB (using composites) to 90/10 fuel/dry mass ratio and you can add 30MT – 40MT to your SDV 2nd stage baseline.

A tricked out inline SDV might well carry 150MT + to LEO, 3x the tricked out EELV.

= = =

A tricked out Delta IV crushes a 1991 design shuttle C – – hey even I agree with that!

A SDV does not does not equate to a more economical way to obtain heavy lift capability. Reconfiguring shuttle based hardware into another launch vehicle negates all system flight history gained from the shuttle program. The loads will not be the same, the vibes will not be the same, etc. A number of SDV designs entail enlarging the current configuration and also require the need to develop an alternative to the expensive SSME. Additionally, the current shuttle launch infrastructure would need to be modified to support the SDV.

SDV statements pertaining to the amount of mass to orbit is not based on a circular orbit as it is with the EELVs. SDV generally states mass to orbit with an orbit of ~30 X 200 at 28.5 and places the responsibility of circularization on the payload. A 30 X 200 is not an orbit, it is a ballistic trajectory.

The EELVs state a mass to orbit with a circular, stable orbit.

The argument for SDV always revolves around the use of the present infrastructure and the present shuttle workforce. The shuttle infrastructure is expensive and a large percentage of the shuttle workforce will be eligible for retirement before the VSE really gets going.

With the reported cost of maintaining the shuttle infrastructure (whether it flies or not) at ~$2-billion/year, one can judge with a decent certainty that the SDV infrastructure will not be economical to maintain.

Any pad mods for a new launch vehicle are instantly in the tens of millions of dollars and new pads are in the hundreds of millions.

The shuttle costs between $750 million to $1 billion per launch. Does anyone really think that with an estimated heavy launch rate of 3-5 per year that number will go down?

The entire EELV program cost the tax payers ~$3-billion.

Technologically, the EELVs are more advanced than the shuttle.

The contractors designed the EELVs to launch 24-30 vehicles per year (both contractors combined) while working one shift per day, five days a week. Imagine around the clock processing.

How many present EELVs can be launched for the cost of 28 shuttle missions?

The argument between SDV and EELV always seems to revolve around the mass to orbit with present EELVs. Do comparisons between the SDV and the spiral developed EELVs.

-Mr. Walker

Then I just don’t understand that analogy either; since the Shuttle couldn’t fly Mir as one module either.

Donald: the Russians could have developed a new launcher to fly Mir as one module — like we did –

No we developed the Saturn V to go to the Moon, …

I was referring to the development of the Shuttle.

If you can keep this Shuttle-derived vehicle under a billion dollars, you’ve got my blessing. But, mark my words, if we spend much more than that on launch vehicles before we actually launch something, we will not return to Earth’s moon in the foreseeable future.

— Donald

It may not be impossible to consider returning to the moon, or going to Mars, without a robust heavy-lift launch capability, but it is certainly silly.

We had a HLV in 1969; we’ve never had antigravity so I that is where the analogy fails. I also don’t know of any effort since then to develop something that would give us that capability again. Shuttle C came the closest, but it was never very seriously considered so I wouldn’t say “decades” were spent on it before it ultimately failed to come to be. What we’ve spent decades trying to develop is a wholly reusable, SSTO vehicle to replace the shuttle, that isn’t analogous to a “simple” STS derived HLV.

As for Salyut; that analogy of the Soviets using some on hand hardware to create something new sounds like what I propose for STS hardware that is on hand and proven.

Donald: the Russians could have developed a new launcher to fly Mir as one module — like we did –

No we developed the Saturn V to go to the Moon, it was used to launch Skylab because it existed. If the Soviet N1 had succeeded it is certain they would have used it to launch their own “Skylab”. And had the Soviet/Russian economy not fallen apart they would now have the HLV we should have, the Energia.

Donald: but who learned how to really operate in space at reasonable cost first?

That is more a function of their society / economy than as a result of the superiority of their method. You can bet that the workers who build Soyuz launchers don’t make anything near the salary of a LockMart or Boeing worker.

Dogsbd, I stand by my analogy. We’ve spent decades failing to develop HLV; throwing more money after bad, in this case, is a lot like chasing after antigravity.

That said, I think I am not being clear. I am _not_ against developing an HLV. What I am against is developing an HLV _first_, before we do anything else.

In the LEO model, what I am advocating is a lot like Salyut. Salyut was developed in a couple of years using the shell from an abandoned project and a launch vehicle developed for something else. It was done quick-and-dirty and far-from-optimized, but it led directly to Mir. Sure, the Russians could have developed a new launcher to fly Mir as one module — like we did — but who learned how to really operate in space at reasonable cost first?

What we need to do if we really want to go to the moon is take some Space Station module, fill it with supplies, get it on the moon with some quick-and-dirty adaptation of an existing launcher, then do the same thing with a crew. _Then_ we can build an HLV to optimize the process _while_ we are actually flying crews to the moon.

— Donald

With the cost of HLLV development included within that $60 billion.