Affordable Heavy Lift

[dwightlooi]

FICTION

FICTION

The basic idea is...

20 tons to orbit: 1-diameter, 2-stages, 1+1 engines, gas generator cycle, no cryogenics, no hypergolics
150 tons to orbit: 1-diameter, 2-stages, 7+1 engines, gas generator cycle, no cryogenics, no hypergolics

Simplicity, costs and reliability are leading priorities.
Performance and technology leadership are secondary.

 

[zacksdad]

no cryogenics, no hypergolics

So that really only leave HTP + RP1 doesn't it?

best talk to the British...

 

[dwightlooi]

no cryogenics, no hypergolics

So that really only leave HTP + RP1 doesn't it?

best talk to the British...

I was referring to LH2 when using the term cryogenics. The concept purposefully avoids an LH2/LOX upper stage even though it'll yield high payload fractions.

I wasn't trying to eliminate LOX. -183 deg C (possibly a bit higher under pressurization) isn't particularly problematic. In general LOX/Kerosene rockets don't need insulation and can remain fueled for reasonably extended periods. This is nowhere near as challenging to handle and use than -253 deg C (near absolute zero) Hydrogen.

HTP + C3H4O is also very good. But C3H4O is toxic and there is no significant industrial production of the substance. Besides, HTP itself is a problem in that HTP becomes not so High Test after a while so there's the shelf life issue.

 

[halman]

We need to examine our design philosophy, because using the highest performance possible is expensive, difficult, and the advantages the highest possible performance provide can be outweighed by simplicity and reliability. Keeping a rocket on the pad fueled and ready to go as soon as the weather breaks is a lot cheaper with LOX and RP1. Neither is difficult to handle, which makes routine procedures a lot easier, and using more engines provides adequate thrust. When we were fighting every pound, trying to maximize the potential payload for a extended mission, it made sense to use LH2. But we just need to get the stuff to Low Earth Orbit, and then we can move it with an Orbital Transfer Vehicle, or couple it to the drive module, or whatever, but LEO is all we have go.

Build in a launch program which will absorb development costs while lifting fuel, living quarters, work shops, a hanger, and a few OTVs, and request delivery dates which promote assembly line construction. Buying the first 10 or 12 copies will make the development more affordable for the company building the rocket, and establish the capabilities of the launch vehicle for the world market. Once we have a way of putting most of a space station in orbit in one launch, I believe that we will see a lot of interest in building space stations.

Of course, we need to couple this heavy lift launch capability with the ability to put lots of people into orbit, so that there will be people to do research, people to help those people, people to keep those people alive, and people to keep the whole thing working. We need a bus, a cheap and easy way to get people into space, without going through the hassles of man-rating a rocket to take off straight up.

See the thread 'A cheap and easy way into space' in this forum for more info.

 

[vulture4]

We should build on the past. I agree that for heavy lift to LEO, two-stage kerosine/oxygen has advantages. Have you looked at the F-1 engine used on the Saturn V? It is really quite ingenious. The regenerative cooling channels extend only half way down the nozzle. The turbopump exhaust is injected into the nozzle through a series of circumferential slots at the bottom of the regeneratively cooled portion, and are said to provide "film cooling" of the nozzle extension, i.e. the lower half of the nozzle, which has no cooling channels. The F-1 was considered to be not only quite powerful (still holding the reord for thrust with a single liquid propellant engine) but was also said to be quite robust and reliable. Of course, unlike the Merlin it used a flat "showerhead" injector plate rather than the single-pintel design of the Merlin, but this may have been an advantage. It had an Isp of 263 (effective exhaust velocity of 2.58 km/sec)

 

[dwightlooi]

We should build on the past. I agree that for heavy lift to LEO, two-stage kerosine/oxygen has advantages. Have you looked at the F-1 engine used on the Saturn V? It is really quite ingenious. The regenerative cooling channels extend only half way down the nozzle. The turbopump exhaust is injected into the nozzle through a series of circumferential slots at the bottom of the regeneratively cooled portion, and are said to provide "film cooling" of the nozzle extension, i.e. the lower half of the nozzle, which has no cooling channels. The F-1 was considered to be not only quite powerful (still holding the reord for thrust with a single liquid propellant engine) but was also said to be quite robust and reliable. Of course, unlike the Merlin it used a flat "showerhead" injector plate rather than the single-pintel design of the Merlin, but this may have been an advantage. It had an Isp of 263 (effective exhaust velocity of 2.58 km/sec)

Well, the "Gryphon" was kinda like an F-1. Except it's a 2 million pounds thrust engine instead of 1.5 million. It's still a gas generator design, but in the interest of cost and simplicity, the turbine exhaust is simply dumped downwards in a tube (ala the SpaceX Merlin). No wrap around, no complicated nozzle extension with slots. Instead of having a nozzle extension cooled by turbine exhaust, we simply do without the extension. Isp actually goes up a few points at SL where the F1 is slightly over expanded to begin with, but drops a few points in Vacuum. This is not necessarily a bad thing since we are using the same engine with a huge nozzle extension to get to 340 secs of Vacuum Isp.