The History And Future Of Spaceplanes

Here is what I think about the present and future of space planes, assuming there is one.

I applaud everyone working to make a workable, lower cost, earth to orbit vehicle, but we have given up the high ground to the neo-luddites by limiting our options. I think, and the equations seem to agree, that chemical fuels are always going to be costly and improvements in performance will be at the margins. The mass fractions will never work. Space advocates should be pushing nuclear power.

After years of seeing irrational obstruction. new nuclear plant licenses are in the works. We should be talking about using nuclear propulsion for our space program and especially anything leaving from Earth orbit.

It’s easy to fault NASA for being to expensive, but private players doing more for less just can’t bring the costs down enough to gather much popular support. If we are going anywhere in the future we will be using nuclear or something else we haven’t even considered seriously.

So I ask, are we fighting for a commercial space program using chemical propulsion because it is the best there is, or just because we know that it is as much as is achievable? I will go along with what works, but I think that changing the popular view of nuclear power will get us into an interplanetary civilization long before even the best non governmental chemical programs will.

I think, and the equations seem to agree, that chemical fuels are always going to be costly and improvements in performance will be at the margins. The mass fractions will never work.

You're wrong. There's nothing in "the equations" that demand that spaceflight be anywhere near as costly as it is now. Cost has little to do with mass fractions.

I have to agree with Anonymous. Chemical rockets can be made substantially cheaper than they are today by rethinking the systems architecture. (With the notable exception of XCOR, where I am obviously biased in their favor, most chemical rocket systems ever built can trace their heritage to taking off from Peenemunde and dropping bombs on London. That's not a systems design that optimizes for operations cost.)

Chemical fuels will always be costly
Kerosene is three bucks a gallon, and LOX is cheaper than beer. Fuel (actually, propellant) is cheap, systems are (currently) expensive.

I'm a big fan of nuclear rockets, beamed propulsion, space elevators, whatever... and I curse NASA for shutting down NIAC which could afford to actually look at some of that stuff. But chemical rockets are good enough to build thriving commercial enterprises from Earth to orbit. Once in LEO, then you can light off your nuclear rocket since, as Jeff Greason says, "space is already radioactive."

"It didn't have to work because it was a test vehicle."

Tattoo that on the forehead of every NASA administrator, Congressional committee chair, and space fan. The more we throttle back impatience for the Breakthrough Operational Vehicle, the better our chances of learning what we need to actually bring it within reach. Festina lente and Reculer pour mieux sauter and all that.

"The reason that the commercial sector is important is because we don't have any choice. We don't have the money to do it the way the government does."

Exactly. I tune out whenever people go off about the wonderfulness of the market, how the private sector is always cheaper and faster and smarter and more lovable than dumb old government. What matters most is that it has to take smaller bites -- and that's what's needed (see above), whoever does it.

Actually, I was "anonymous." Sorry 'bout that.

First ever composite linerless oxygen tank, long before X-33 tank failed a few years later.

This might be a little misleading for those who didn't follow X-33 closely (probably the ambiguity of hurried liveblogging). The LOX tank on X-33 wasn't composite (aluminum), and the composite tank that failed was an LH2 tank.

"Pure energy price to put a person into orbit is about $76."

Whoa. Could someone elaborate on what this means? This is the lowest figure I've every seen for reaching orbit. If kerosene is $3/gallon, does that mean it only takes 25 gallons of kerosene to put someone into orbit? Or is that some other kind of fuel? What kind of energy are we talking about here? Am I right to assume that this number does not include "minimal" shielding / ship weight?

Theoretically, if we developed a one-seater rocket that weighed 150 pounds (it's pure composite), ran on autopilot (no salary for pilots), and was mass produced for $75, does that mean $75+75+75 = $225 to orbit, not including the cost of your suit and a filled air tank? Is that what this means?

I assume that it's a calculation purely of the energy difference (kinetic and potential) between being in orbit and on the ground, including no consideration of how this is achieved.