Transterrestrial Musings

« A Couple More Anniversaries | Main | "He's Dead, Jim" »

How Can I Count The Ways?

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.

Posted by Rand Simberg at July 20, 2005 08:28 AM

Comments

Thanks for the link Rand!

Posted by Jonathan Goff at July 20, 2005 09:49 AM

That's an interesting reply, though you rephrase my term "not sufficiently commercial" to "uneconomical." I also don't understand how launching things in smaller bits makes the system more robust. If the launch vehicle with the Crewed module gets to orbit and the launch vehicle with--say--the lunar lander explodes, then your mission is in as much trouble as if a bigger launcher with all the pieces doesn't make orbit. In fact, it seems to me that you're taking two or three chances for your lunar mission to be aborted in that way than with a single launch option.

It's not that I necessarily agree with one way or the other. I suspect that when private business gets around to going to the Moon on it's own, it may well use the EOR option--at least at first.

Posted by Mark R. Whittington at July 20, 2005 12:17 PM

Mark,

I'll comment on your blog post later (probably on my own blog) if I get a chance. I think you're missing something though in your comment here:

"I also don't understand how launching things in smaller bits makes the system more robust. If the launch vehicle with the Crewed module gets to orbit and the launch vehicle with--say--the lunar lander explodes, then your mission is in as much trouble as if a bigger launcher with all the pieces doesn't make orbit. In fact, it seems to me that you're taking two or three chances for your lunar mission to be aborted in that way than with a single launch option."

You aren't thinking out how this would actually happen in reality. In reality, you'd probably put your lunar lander vehicle up first. [You'd also probably have spares, and probably design the thing to be reusable/refuelable in LUNO, so the destruction of anyone lander isn't as big of an issue] You'd check out the lander in orbit, make sure it got there ok, and is functioning. Then you'd launch the transfer stage. You'd probably have spares of those too (and likely have them be refuelable/reusable). Then you'd launch fuel runs, and if any one of those fails, it isn't a big deal--fuel and fuel tanks are pretty cheap compared to the rest of the system. Lastly, once that's all checked out and ready to go would you launch the people in the crewed module. You'd plan this in advance with some margin so that you could get them all there are ready to go before your launch window to the moon.

While your odds of losing something by taking this route is higher, the odds are that you will lose less, and will have less odds of having to scrub the mission.

Most importantly, it'll be cheaper.

Posted by Jonathan Goff at July 20, 2005 12:30 PM

That's an interesting reply, though you rephrase my term "not sufficiently commercial" to "uneconomical."

I'm not "rephrasing" it, Mark. You're the one who constructed the strawman of "not sufficiently commercial." I certainly never wrote that. I was simply describing my actual view of the problem, rather than what you misinterpreted as my view of the problem.

I also don't understand how launching things in smaller bits makes the system more robust. If the launch vehicle with the Crewed module gets to orbit and the launch vehicle with--say--the lunar lander explodes, then your mission is in as much trouble as if a bigger launcher with all the pieces doesn't make orbit.

Because in that case, you've only lost a lunar lander. The rest of mission elements just have to stay up in orbit, awaiting the delivery of another one. It doesn't all have to be replaced.

In fact, it seems to me that you're taking two or three chances for your lunar mission to be aborted in that way than with a single launch option.

Yes, you may be increasing the likelihood of a failure, but you're reducing the consequence of it. In addition, flying more often is likely to result in better reliability, through economies of scale and increased experience in launch personnel.

That's in fact one more argument against heavy lift.

Posted by Rand Simberg at July 20, 2005 12:31 PM

Mark,

I'll comment on your blog post later (probably on my own blog) if I get a chance. I think you're missing something though in your comment here:

While your odds of losing something by taking this route is higher, the odds are that you will lose less, and will have less odds of having to scrub the mission.

Most importantly, it'll be cheaper.

Posted by Jonathan Goff at July 20, 2005 12:31 PM

"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.

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.

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.

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.)

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. That's a cost. Also, how fast can you launch? Are there enough launch pads free to support the program without impacting other customers like comsats? 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?

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?

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.

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.

Posted by Tim Faber at July 20, 2005 12:53 PM

Nice points made about the refueling, and its necessity to avoid needlessly throwing away the trans-lunar vehicle (or even lander). However, one problem not mentioned (and please, this is just a nit, not an attempt to disagree with the article) is that besides propellant, equipment inside the vehicle fails.

ISS and Mir are great examples of this. For ISS, it was expected that nearly 2/3rds (especially with a 3 person crew) would be spent maintaining the vessel. That maintenance requires logistics spares. So again, a nit, delivery of spare parts is as essential as propellant. I make this nit, because some who prefer HLV do so because a vehicle that can carry all its maintenance supplys and necessary propellant will be quite hefty. Even if you load additional propellant on orbit from another vehicle, proponents of HLV will point to a need to carry a larger payload, so that spare parts are already on board.

Posted by Leland at July 20, 2005 02:00 PM

"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."

Reading all your responses, you are proposing a pretty complex solution of your own. Your solution requires highly reliable reusable launch vehicles (no existence proof), on-orbit refueling in large amounts (also not done yet), substantial on-orbit integration (still underway on ISS), long duration on-orbit storage of propellants (not done yet for cryos at least). And you assure us with confidence that basing a lunar exploration architecture on so many unproven elements is "better" than basing it on an HLV.

That's exactly what I meant by handwaving. Confidently asserting that things that have never been done are "not that hard to do" (paraphrasing)--and that a multi-billion dollar program should be based upon them. One can posit that a pig with wings will fly quite well. If a pig had wings.

Posted by Tim Faber at July 20, 2005 02:11 PM

I am stipulating that the architecture that I propose would be more flexible, more robust, and provide more capability for opening up space for activities than repeating an approach (Apollo, with a heavy lift expendable vehicle and minimal orbital assembly) that demonstrably didn't do that the last time we tried. Your only rebuttal seems to be that there's no "existence proofs" for technologies that don't defy any laws of physics, and that we actually do have some experience with.

By your absurd standards, we couldn't have done Apollo in 1961, because there was no "existence proof" of a large launch vehicle, there was no "existence proof" of the ability to perform rendezvous, there was no "existence proof" of the ability to dock, there was no "existence proof" of the ability to keep humans alive and healthy in space for days. But we decided to develop all of this, because they were needed in order to accomplish the goal. The technologies I propose are much better understood now than any of those others were in 1961.

Are you one of those people who thinks that nothing can ever, or should ever, be done for the first time?

Posted by Rand Simberg at July 20, 2005 02:20 PM

Leland,

As for spare parts, I completely agree they'll be important. At least the lander portion can be serviced on the lunar surface. That's a convenient place to work on things if you set things up right. The orbital segment will require maintenance, and that will be interesting to figure out. But it's the price you pay for lower costs and better operability.

~Jon

Posted by Jonathan Goff at July 20, 2005 02:40 PM

It seems to me that the case for smaller launch vehicles is that you don't lose the whole thing if one launch fails means you need spares. If you are going to have spares, you can have spares for an HLV also. You'll need a backup for every element you can lose in a launch failure.

It seems to me there is a tradeoff between HLV and MLV. If we had a rocket that could orbit only 1kg but it was free, I don't think that would be cost effective for any mission. That's one extreme end of the small vs. big launcher question. Where is the other end and where is the optimum. An MLV puts more constraints on your space vehicle design which could raise cost and complexity. A one story house makes better use of it's floor space than a 3 story house. A 3 story house needs space for stairs not required by a one story house.

I think it depends on the mission. We get our oil in super tankers because for that mission, it's the most cost effective. I get my pizza delivered by a guy in a VW Jetta because that's the most cost effective for that mission

We have to avoid choosing our mission to satisfy our launch vehicles. We should decide what we want to do and figure out which combination of launch vehicles works best. I can send a few men to the moon using MLVs and it would probably be most cost effective. But I think building a moon base would be better built using an HLV. I can send a big tractor to scoop moon dirt on an HLV but I can only send shovels on an MLV. (Obviously overstated but you get the point I hope)

To back up what Tim said. We used 1 HLV to go to the moon in a 2 week mission. Would it really have cost less to make 3 or 4 launches and assembled in orbit? How long would that have taken? Several months? There is manpower associated with that. See the conversation with the TGV folks over at http://www.thespacereview.com/. They make a good argument for cheap operations. I think multiple launches would have a higher operational cost over a single launch. I don't see how a bigger rocket takes more people than a smaller rocket. But I can see how multiple launches need more people (or same number for a lot longer) than a single launch.

If we plan to be in space to stay, we'll need a variety of vehicles. I think starting with MLV's would be OK, but I hope that we sould eventually grow to the point where we need to launch larger items, but we'll have the Space Elevator by then ;-)

Posted by tautala at July 20, 2005 02:44 PM

Rand, Jon, unless one is contemplating a different type of launch vehicle for each of the pieces of the CEV vehicle, then your scenario leaves out one fact. A launch failure of--say--a Delta IV is going to ground the fleet for a period of time while the cause is assertained. So it seems to me that the mission is still blown, unless you've designed the various pieces to survive and function in LEO for however time it'll take to fix the problem. Maybe that would be the way to make EOR work. I'm not sure.

You've also haven't addressed the Griffin objection that it would actually cost more to "man rate" an EELV than it would to buid an SDV. I'm rather anxious to find out why you think he's all wrong.

Posted by Mark R. Whittington at July 20, 2005 03:40 PM

You've also haven't addressed the Griffin objection that it would actually cost more to "man rate" an EELV than it would to build an SDV. I'm rather anxious to find out why you think he's all wrong.

This point is argued on sci.space every couple of weeks. Rand (and others, including Henry Spencer and George Herbert) usually then point out that 'man rating' is an arbitrary concept and that by NASA's own definition, the shuttle isn't man rated itself. This is usually also followed by the point that manrating has more to do with surviveability (forex, with a CEV with an escape tower) than it is about reliability.)

However, failing the majik appearance of a fully reusable launch vehicle, I think the extensive flight history and proven post flight inspection process on the SRSMs in the (much derided) Stick concept trumps a lot of the 'component-level' man rating argument.

Posted by cuddihy at July 20, 2005 04:55 PM

> Rand, Jon, unless one is contemplating a different type of launch
> vehicle for each of the pieces of the CEV vehicle, then your scenario
> leaves out one fact. A launch failure of--say--a Delta IV is going to
> ground the fleet for a period of time while the cause is assertained.

By that reasoning, Federal Express needs a different type of airplane for every package. Otherwise, the failure of -- say -- a 737 is going to ground the fleet for a period of time while the cause is ascertained.

Of course, Federal Express does not need a different type of airplane for every package. All of their planes are designed to carry a wide variety of packages. Why should a space transport be designed to carry only one specific type of cargo?

Why would you design a component so it could fly on a Delta IV and only a Delta IV? Are you deliberately designing for unreliability?

> So it seems to me that the mission is still blown, unless you've designed
> the various pieces to survive and function in LEO for however time it'll take
> to fix the problem. Maybe that would be the way to make EOR work. I'm not sure.

So, it would be impossible to design a system where a large number of pieces had to rendezvous in, say, Memphis? Then get sorted, reassembled, and routed in a timely manner?

Federal Express does that every night.

Posted by Edward Wright at July 20, 2005 06:31 PM

Using Mark's "reliability" argument, all government officials should fly together on one giant airplane. (The President's 747 will have to do until NASA can develop something bigger.)

Since airplanes are not perfect, this will minimize the likelihood of losing a government official in an airplane crash.

The loss of one official could bring the entire government to a halt, so if we lose one of them, we might as well lose them all.

Finally, if an airplane crashes, all airplanes will be grounded until the cause is determined. So, we must ensure that all government officials are in the same place when that happens.

Hm. I'm not sure, but there might be a flaw in this line of reasoning.

Posted by Edward Wright at July 20, 2005 06:45 PM

> I can send a few men to the moon using MLVs and it would probably
> be most cost effective. But I think building a moon base would be better
> built using an HLV. I can send a big tractor to scoop moon dirt on
> an HLV but I can only send shovels on an MLV.

DC-3s carried lots of tractors during World War II. That doesn't require a medium launch vehicle, much less a heavy launch vehicle. They built scores of bases, also. Real bases, that required assembly, not little prefab things you could launch on an HLV.

Posted by at July 20, 2005 08:01 PM

I don't know, this whole thing seems like a silly argument. HLV vs. MLV is in the same vein as 'let's go straight to Mars' vs. 'let's go back to the Moon!' It's silly because if we are really to become a space-faring civilization, it will be both, not one or the other.
Likewise, it doesn't matter whether NASA picks an HLV or MLV architecture. Either one isn't going to affect Bob Bigelow's tourism architecture. Just like it doesn't matter to Antarctic tourism if the US Navy uses C-130s or or some proprietary C-5 derivative to move their equipment to the South Pole: either way, they're not going to give you a free ride, and you're not going to buy a spare one to do it yourself unless you feel like throwing away money. And no matter which one the Navy uses, it's not going to affect your business model. And it shouldn't.

Posted by cuddihy at July 21, 2005 12:29 AM

Theres one more aspect to this. The way i see it, robust in-space rendezvous and docking, fuel transfers and also reuseable space vehicles ( both in-space and space-to-surface ) will have to become a reality eventually anyway, if we are to build space-based industries and economies in the future.
So making your launchers bigger right now is just pushing the point where you have to bite the bullet and develop such technologies anyway forward into the future.

Also lets not forget that we have _overcapacity_ on the market of medium launch vehicles, the assembly lines and workers are sitting idle. Not in ukraine and russia, mind you, but in U S of A.

Posted by kert at July 21, 2005 01:41 AM

SimBerg: "I am stipulating that the architecture that I propose would be more flexible, more robust, and provide more capability for opening up space for activities than repeating an approach (Apollo, with a heavy lift expendable vehicle and minimal orbital assembly) that demonstrably didn't do that the last time we tried."

The argument that we failed in opening up space the last time we tried is a bit misleading, as there was no last time. The objective of Apollo was not "opening up space" only to get to the Moon before the Russians. We’ll never know if the capacity represented by the Apollo hardware could have opened up space since we, as LBJ put it, pissed it away.

Posted by Cecil Trotter at July 21, 2005 05:12 AM

Doesn't the plan that is currently being laid out by Griffin at least attempt to satisfy both sides of the argument. We have the HLV derived from Shuttle components to give designers the option to come up with any number of concepts to meet mission goals. On top of that their is still the problem that a lot of ISS hardware is sitting on the ground and it is looking more and more like the Shuttle is not going to get a chance to lift any of it. We can expand the number of flight required by an HLV by adapting the ISS hardware to be lofted by a Magnum booster. The HLV will potentially give mission managers the flexibility to implement more robust mission goals based upon larger subset of concept sizes and shapes.

The CEV is purely intended for a MLV which will attempt to satisfy our need for lowering operational costs through increased launch rates. NASA is looking at the concept of not putting all their eggs in one basket in a slightly different manner. To them, their eggs, are the astronauts and that basket needs to be the one going down the path of reliable infrastructure development. I would say the complex yet inorganic items like: reusable lunar landers, refillable fuel depots, orbital tugs, and the like, should go up on the big dumb heavy boosters. All those objects that we know need to be replenished and exchanged from the surface to orbit on the regular basis should be specifically designed for the MLV option.

Isn't the path to reliable space infrastructure keeping as many options open as we can? Doesn't that number of options go up signicantly the longer we can hang onto both HLV and MLV implemented designs? Isn't the most successful plan the one that involves a mix of both old and new methodologies?

Posted by Josh Reiter at July 21, 2005 07:29 AM

Part of the problem is that the SDHLV serves no other market but NASA. No business or combinations of businesses are going to risk that much in capital investment at one time.

Sure you could launch a dozen GEO comm sats at one time, but does it make sense?

Sure you could launch 4-6 Bigelow balloons at once, but does it make sense?

Sure you could launch 150 fully loaded International Standard Payload Racks up to ISS, but does it make sense?

No one is going to risk that quantity of assets in one go (one word: insurance). The only entity an SDHLV would serve is NASA. The only mission for which it is really optimised is a quick trip to the Moon with minimal facilities, then off to Mars, ASAP. It ignores all the other opportunities and possibilities and capabilities that await us just between here and the Moon (though Griffin seems to think, or at least concede, SEL-2 is a good destination [which it really isn't]).

This serves neither the goals and objectives of the VSE, nor the interests of American commerce and industry. Do the taxpayers really want their money going into a private launch system for NASA going forward (15, 20, 30 years)? Or would those taxpayer dollars be better spent buying transport the same way everyone else does and using the savings for other cool stuff.

Be it EELV or RLV I don't care. The point is that we need to get large numbers of launches to LEO to achieve that most precious of industrial gifts, mass-production. We must move beyond the guild age of hand-crafted vehicles if we are to really make something of our space efforts. We've hurdled the barriers to entry to space, and few others have. There are four vehicles worldwide in the 20 mt payload range. Two are in the U.S.
Bigelow's designing his balloons in that payload range. Half a dozen teams submitted CEV proposals in that payload range. Comm sat folks are starting to get comfortable with launching 2 satellites at the same time, with hitchhikers. It's a good, manageable size for payloads, and there are facilities that can handle it, like SpaceHab's Astrotech facility in Fla., which can handle the new 5m fairing class of payloads. Boeing can produce 40 common cores in a year (they're not).

There are a lot of folks who want to do business in space.

Thanks a lot NASA for kicking sand in our face."

Posted by Ken Murphy at July 21, 2005 11:01 AM

> The CEV is purely intended for a MLV which will attempt to satisfy our need for lowering operationa
>l costs through increased launch rates.

Six launches will not provide any meaningful increase in launches.

Nor is CEV, as currently conceived, capable of flying on any medium launch vehicle. At 28 tons, it won't even fit on Delta IV Heavy. Griffin proposes developing an entirely new launcher, larger than any existing launch vehicle. Calling it a "medium" launch vehicle is just a sales tactic.

> We can expand the number of flight required by an HLV by adapting the ISS hardware to be lofted by a Magnum booster.

Not to any significant extent. We won't get meaningful cost reductions by expanding the number of flights from 8 to 19.

To get meaningful reducations, we need hundreds of flights, in the near term, followed by thousands.

> Isn't the path to reliable space infrastructure keeping as many options open as we can?

No. the path to reliable space infrastructure is developing *affordable* options. The options you propose would prevent NASA from developing any significant space infrastructure. None of those big rockets will ever fly often enough to pay for itself.

Posted by Edward Wright at July 21, 2005 11:09 AM

How do you eat an elephant? One bite at a time.

I think most, if not everybody, here would agree that we want a sustainable commercial (anybody with the money can buy a ticket) space program.

Low gravity refueling is a no brainer and we should develop it (in such a way that we don't need to reinvent it every time we need to do it.)

The question of what the launch system is going to need to be is answered by first asking what it is that is going to be launched. The answer to that question is a long-life multi-mission vehicle (eh, let's call it the spacecraft. Spaceship? That's so Buck Rogers!) for long duration space flight.

We already know how to put people in orbit, pick one or use the next generation of x-prise winners.

A landing and ascent vehicle can be launched separately and docked with your spacecraft. We know how to do this, been there, done that.

The only real question is what is the design of your reusable, multi-mission, never lands anywhere, you can live comfortably in it for years at a time, vehicle going to be. Which then answers the question of what we need to launch it with.

I've left out the habitat at the destination, but that isn't much more difficult than launching a few rovers to Mars (and landing close enough to each other to be useful... better pack a moon buggy with the lander, eh?)

Heavy lift is a capability. It's not the story.

Posted by ken anthony at July 21, 2005 07:20 PM

Oh, BTW, someone here offered free rockets with 1kg payload to LEO. Please, could i have about ten thousand of them ASAP ? Even if half of them miss, i'd still have sufficient fuel up there for a robotic lunar ice searching mission that would cost me an awful lot otherwise to launch.
Ah, and as the fuel would be basically free i can use as low ISP propulsion as i like, so whats the most benign liquid monoprop to store ? Hydrogen peroxide ?

Posted by kert at July 22, 2005 02:10 AM

Post a comment