Category Archives: Business

Truth To Power

At GLEX, I just asked Mike Griffin from the floor what the payload was which demanded to be sent up in a single launch that demanded a Saturn-class vehicle.  He responded by saying that this wasn’t the place to debate it, and then with a straw man about sending things up screw by screw.  Buzz had previously softened him up with a comment about the need for more innovation and fewer jobs programs for the launch vehicles. He initiated the discussion with a slam at propellant depots.

[Update later evening]

I typed that from my phone. Here’s a fuller story. Mike (without prompting) stated that heavy-lift is the highest priority for space exploration, and that depots would be useful, but not immediately so. Ian Pryke agreed with him. Buzz responded (from the second row) as noted above. I then asked the panel (not Mike specifically) from the back of the (full) room the question above. His response (from memory, not an exact quote):

Rand, we’ve been arguing about this for years and this isn’t the place to debate it. It’s possible to break a vehicle down to individual nuts and bolts, and launch it that way. But there is a reason that we deliver crude oil in large tanker ships and [several more examples of large vehicles delivering stuff]. I don’t understand why space transportation is different than any other kind of transportation. We can argue about this forever, but at some point we just have to rely on common sense.

My response (here): Note that he didn’t answer the question, nor did he explain why a quarter of a million pounds was the right answer. The nuts and bolts thing is a strawman. Surely there is some optimimum, some happy medium between one fastener at a time, and a Saturn V delivering everything at once, fully fueled.

The reason that space transportation is different (at this time) than other kinds is because it is a new industry with a limited market, and there is insufficient traffic to amortize the development of such a large vehicle that will fly so rarely. It makes sense to build dozens of oil tankers to carry millions of tons of oil. For a vehicle that will deliver a hundred-plus tons once or twice a year, not so much. The first practical airplane, from an airline standpoint, was a DC-3, not a 747. There are other reasons it is different, but that one by itself should suffice.

Briefly, I refuse to concede to Mike’s condescending (and insulting) claim that he has a monopoly on common sense. And I understand that it wasn’t the right place for a debate. In his mind, there is no right place for a debate because a) he thinks there is no need for a debate and b) he knows that if he were ever to have one with me, he’d get creamed (at least judging by the last round between Space News and Competitive Space). Plus, he would never dare legitimize me or my arguments by debating me, just as Michael Mann and Briffa and Jones and Hansen refuse to come to the Heartland conference to debate.

[Bumped]

For Want Of A Check Valve

My piece on the SpaceX abort is up at Popular Mechanics.

Here’s the bit that got left on the cutting-room floor:

But even as the incident validated the safety of the vehicle, it raises issues about its launch reliability (that is, the ability to launch on schedule). Every rocket design is a compromise of cost, safety and reliability. In the case of the Falcon, it has nine Merlin engines in the first stage because this allows it to use the same engine in both that stage and the upper stage, which only has one (with a larger nozzle for vacuum operation). This saved a great deal in development costs, and provides economies of scale in manufacturing, with a steady production of them 24/7 in the company’s factory in Hawthorne. It also provides a more forgiving design, allowing engines out on ascent, while also allowing the functional capability to “deep throttle” the stage by selectively shutting down engines to maintain gee limits for crew.

But nine engines also means nine times the things that can go wrong and prevent a launch. In fact it’s worse than that. It actually increases the unreliability exponentially. For instance, if the probability of an event like Saturday’s for one engine is one in a thousand, the probability of it not happening on any one of the engines is 0.999 to the ninth power, or .991, which means that there’s about a one in a hundred chance of an abort. If it’s only one in a hundred, that means that there will be an abort every tenth flight or so. And that’s just for Falcon 9. Falcon Heavy will have twenty-seven first-stage engines, which means a probability of abort of almost three in a hundred for a one in a thousand single-engine reliability, and a probability of one in four for one in a hundred.

The company doesn’t have enough experience with this vehicle to know what its true reliability is, but if they continue to have pad aborts, they may decide that they’d like to get bigger, and fewer engines.

But it also raises the issue of the value of a flight-readiness firing (FRF), as SpaceX performed a few days ago, with a hold-down test of the first-stage engines on the launch pad for a few seconds a few days ago, in preparation for this launch. The Space Shuttle also did this each time before the maiden launch of an orbiter, to ensure that all systems were ready to go before the first flight, but it was a reusable vehicle. Max Hunter, developer of the Thor that evolved into the Delta in the sixties, used to say that FRFs caused more problems than they solved, because a clean vehicle from the factory could be damaged or worn in the process, making it less reliable for actual flight. The valve seemed to have worked all right in SpaceX’s FRF, and it’s unclear (though SpaceX may know) whether or not the failure was a result of the FRF (I would bet they’re already reviewing the data to see if they saw any anomalies toward the end of the test, if they haven’t already).

But unlike the Delta, either ancient or modern, the company has a goal of full reusability for the vehicle, including the engines, so it may make sense to do FRF, at least once they start to refly, when they won’t have to do it for every flight. But the incident has no doubt given Mr. Musk and his team quite a bit to think about.

I will be curious to hear what they think the cause of the valve failure was.

Kickstarter Funding Progress

Things got off to a good start late last week, but donations slowed down over the weekend. I’m a little less than a third of the way, at $2160, with a three and a half weeks to go. That’s plenty of time, but I fear that I’ve already plucked all the low-hanging fruit, so spread the word, please.

I’m flying to DC tomorrow to go to the Global Exploration and International space Development conferences, so I may try to get face time with potential larger donors for matching donations. It also might help if folks would comment over there to entice new donors who come across it.