Jon Goff argues against heavy lift (one of my hobby horses as well, as long-time readers are aware, and as today’s Apollo anniversary piece hints at).

[Update at 2:05 PM EDT]

Mark Whittington takes issue with us:

There are technical arguments, one suspects, for doing it either way. But the real sticking point, it seems to me, is the idea that using heavy lift is insufficiently commercial, that it’s just another bad old, big government, dead end way of doing things.

No, that’s not the sticking point. The sticking point, as was explained at length in Jon’s post, but which Mark didn’t seem to have read, is that it’s uneconomical, and makes for an extremely fragile infrastructure. If we’re dependent on a single launch system type to get to the moon, and we make that vehicle so large that we’re putting all of our mission eggs in a single basket, then a stand down of the vehicle fleet (as we’ve seen occur twice with Shuttle now, each time for over two and a half years) stands down your capability to get to the Moon, and any single launch failure adds up to a loss of not only the launch vehicle, but billions of dollars worth of expensive hardware. Putting things up in smaller pieces, with multiple vehicle types, lends much more resiliency to the infrastructure, and any given launch accident (as is inevitable) will result in much less loss. In addition, launching smaller things more often is much more efficient in terms of operational economies of scale, and utilizing work forces.

This has nothing to do with government versus commercial, per se. It has to do with affordability, and sustainability, characteristics upon which the VSE is supposed to place a high value.

The commercial space sector right now is building on Burt Rutan’s achievement to build suborbital space ships to give the well heeled and adventurous thrill rides.

Really? Is that all it’s doing? What are Elon Musk and Bob Bigelow up to, then?

[Update at 3:40 PM EDT]

Well, we’ve got quite the debate going in the comments section.

Let me respond to this comment in the main post, because it contains many of the myths and bad assumptions that characterize the debate.

“In addition, launching smaller things more often is much more efficient in terms of operational economies of scale, and utilizing work forces.”

The problem with this debate is that there are a lot of assertions and no good evidence. I’ve not seen any detailed cost analyses of the HLLV vs. multiple ELV options.

Well, I wasn’t comparing HLLV to multiple ELVs (which are almost as bad from a cost standpoint, though more resilient)–I was describing space transports. But in any event, that should be remedied soon. George William Herbert has written a lengthy paper on this subject that is undergoing review right now by me and others smarter than me, and should be published soon, either at The Space Review, or here (if he’d like).

The anti-HLLV crowd claims that all kinds of money can be saved, while handwaving aside the fact that putting things up in lots of little pieces creates additional costs in terms of operational mass, R&D, and technical restrictions.

We’re not “handwaving” it aside.

For instance, put one big piece up and you don’t have to waste extra mass on docking collars and associated equipment. Put it up in five smaller pieces and each of those pieces has to carry equipment to enable it to be hooked together. That could include docking collars, extra rendezvous and maneuvering equipment and fuel, and other things. Plus, now you have to do the payload integration in orbit rather than on the ground, where it is easier. Run a data network through your spacecraft and if it is in multiple pieces, you have to connect every piece up to that data network. Ditto for power.

Many of these problems go away with a space-based orbital tug. As far as general overhead, the costs of this can be estimated, and this is an issue that George’s paper will address.

Also, putting it up in lots of little pieces requires new R&D. For instance, nobody has done on-orbit refueling yet, let alone refueling involving large amounts of fuel and/or LOX. I’m not saying that this is impossible to do, but it _has not been done._ So if your approach requires it, then you have to develop that capability and that means expending R&D dollars. (So those who claim that you don’t have to spend R&D dollars on developing a new launch vehicle have just created a requirement for the R&D to be spent on something else entirely.)

Well, actually, the Russians have demonstrated orbital fueling–it’s just a matter of scaling it up. It hasn’t been demonstrated for cryos yet, but that could be done at the ISS (something more useful than almost anything that it’s done so far).

But the point is that no matter what we do, it’s going to require R&D. The question is how we spend that R&D. I would prefer to spend it in directions that give us more flexibility, more resiliency, and in ways that develop more of the technologies that will be necessary for us to become truly spacefaring (e.g., orbital assembly, orbital fueling, routine rendezvous and EVA, etc), rather than on a new large vehicle that will lead to a fragile and inflexible infrastructure.

Then there are other costs. If you are going to do on-orbit refueling over a substantial period of time, then cryos are out. So you lose that ISP and you drive on-orbit mass up.

You can store cryos in an orbital depot for an indefinite period of time, through good insulation and active refrigeration.

Also, how fast can you launch? Are there enough launch pads free to support the program without impacting other customers like comsats?

How fast you can launch depends on how intelligently you design your launch vehicles, and what kind of turnaround time they have, and whether or not they require “pads” (e.g., Pegasus doesn’t, nor will any vehicle designed by Rutan), and whether or not you’ll have to launch out of the Cape.

If you plan on substantial on-orbit assembly, it may take many months of orbital operations simply to get your vehicle built. What kind of costs are associated with that? Do we really want to assemble each lunar mission like we are currently assembling the ISS?

No, we want to do it much smarter than that. And ISS is much more complicated than the kinds of things we’re proposing.

And then there’s the fact that the industrial base to support payload preparation is finite. Are you really going to be able to hire and train enough people to have perhaps a dozen payloads in preparation for launch simultaneously?

I’m sorry, but this is simply an absurd question. We live in a nation of three hundred million people. The notion that we couldn’t hire people to operate a well-designed system (one that’s optimized for cost, rather than maximizing jobs in Brevard County) is ludicrous. And it’s ludicrous even if we do it the NASA way.

Right now rockets fail at a (best) rate of 1-2%. Multiply that number by the number of launches you want to conduct and you have increased the chances that something blows up on its way to orbit. If the rocket that blows up is the same one that you also employ to carry your people, the rocket will be grounded until the problem is found and fixed. So all that hardware hangs in orbit until the program is resumed.

That’s the failure rate for expendable systems (which the Shuttle counts as, since it’s the expendable components of it that have caused its problems). The failure rate for a well-designed space transport would be much lower, because you’d eliminate the infant mortality problems caused by the fact that for expendables, each flight is a first flight. You’ll get more reliability through better statistical process control as your activity level goes up, something impossible when you only launch a few times a year.

And when you start to consider human Mars missions, the idea of doing it as small missions really looks impossible. The requirements for a human Mars mission are about 500 metric tons in earth orbit. It is not realistic to think about doing that in 10-20 metric ton increments.

Most of that mass is propellant, which can be delivered in whatever size increments you want. This argument is like saying it’s not realistic to build a house unless you develop a truck that can carry the entire thing to the building site. Simply saying that something is “unrealistic,” with no support, is an uncompelling argument. It’s less a sign of realism than a failure of imagination and innovation. The sixties are over. Get over it.