I’ve got the presentation that Dallas Bienhoff gave in Long Beach last week that implicitly demonstrated the lack of need for a heavy lifter.
Note the element weights on page 6. The heaviest item is the depot at twenty tons, but that could go up in three flights. After that is the lander, at twelve tons. That sets the minimum throw weight for the launcher. It’s about ten percent of the eventual capability of the SLS.
[Update a few minutes later]
What’s funny is that the paper doesn’t just bury the lede — it leaves it out entirely. Note that nowhere in it, including the final chart describing the benefits quantitatively, does the phrase “heavy lift” appear. Because Boeing is not allowed to actually say that heavy-lift isn’t needed, even if that’s what their own analysis shows.
Wait, you mean Gaetano’s wrong about needing at least 95 tons?!?! Unpossible!
I know! That flies in the face of all his MS Paint drawings.
No surprise. Almost none (might have been NONE) of the “concept exploration and refinement” studies done on how to implement the Vision for Space exploration identified a need for a heavy lifter. Companies were free to choose one, if they had found it cost effective to do so. When Mike Griffin became NASA administrator, all those studies on HOW to return to the Moon were round-filed in favor of the Big Rocket.
Of course, if Falcon Heavy flies it’ll be a different story, because “cost effective” actually has a meaning.
But Falcon Heavy only carries 53 tons to LEO. How can we do Apollo On Steroids with something half the size of a Saturn V? Enough with these puny girly-man HLVs; we want Ares 5++! At any price!
Does Musk have any interest in the moon or orbital propellant depots? It’s always seemed to me he’s an orthodox Zubrinite. Hence his desire for a monster HLV.
Now Rand, don’t get Dallas in trouble. I’m still hoping Boeing management will someday allow us to publish the paper that went with our presentation from the SSI conference.
Yes, and if you also look at the mass of comsats — you know, the only commercial market sector that exists today — you’ll see that their Beginning of Life (BoL) mass in GEO is less than 4t. So, not only would exploration benefit from in-orbit infrastructure like propellant depots and orbit transfer vehicles, the comsat market could also be better served by small (reusable?) launchers that would be cheaper to both build and operate as commercial ventures.
Doesn’t it all depend on how much a kilogram really is? ;^)
…or what “is” is.
“So, not only would exploration benefit from in-orbit infrastructure like propellant depots and orbit transfer vehicles, the comsat market could also be better served by small (reusable?) launchers that would be cheaper to both build and operate as commercial ventures.”
A fully reusable launch vehicle has to be small in order to achieve the right balance of development and production cost, and flight rate over which to amortize those costs. It’s likely that expendables would have a different size requirement, which might allow a larger payload than a reusable — but not as large as the SLS.
In the past 30 years, all attempts to advance the state of launch vehicles have failed because the design point was always (arbitrarily) set at a minimum of 60,000 pounds to LEO. There is no market to sustain that. The one market that does exist (GEO sats) can be serviced by a very small reusable that hauls parts (rather than complete satellites) into LEO for assembly there. The business case for that closes at a payload weight between 5,000 and 8,000 pounds.
The key elements of this architecture are EML depots, reusable lunar landers and lunar ISRU fuel with LEO depots being a nice follow on feature.
PS – I agree 100% that this architecture can be run without an HLV, especially without an SD-HLV. Falcon Heavy would be more than sufficient.
Nonetheless, it would seem SD-HLV will remain necessary if folks want the US government to pay the bills associated with running an architecture like this.
demonstrated the lack of need for a heavy lifter..
Awesome. One needs to demonstrate the lack of the need.
Was the need demonstrated anywhere first ?
“What’s funny is that the paper doesn’t just bury the lede — it leaves it out entirely.”
Much like another work that spoke the truth when the powers-that-be (or were) didn’t want to hear it, namely Copernicus’s On the Revolutions of the Celestial Spheres, and probably for similar reasons. Copernicus expressed his belief in a heliocentric solar system so cautiously that it’s hard to figure out what he’s driving at unless you know already.