Last week, Chief NASA Administrator Charles Bolden announced that the agency had finally decided on a new launch system, named the Space Launch System (SLS), that didn’t have the fatal flaw of having anything to do with former President George W. Bush. But the design has new flaws, most of them related to the fact that NASA is incapable of making technical decisions uncorrupted by politics. Given the chance to start fresh, letting engineers design an optimal rocket based on the mission of getting men into space as efficiently as possible, they instead chose to do what NASA has always done since the 70’s. They designed the new rocket by committee, resulting in a Frankenstein monster using parts, engines and design aspects of many different launch systems, especially the Shuttle, so that existing technologies could be “leveraged,” meaning that existing contracting relationships in certain Congressional districts would not be disturbed too much and we could make use of some of the junk still lying around from the Shuttle fly-out. Brilliant. Save a little right now and waste a fortune in the long run.
It’s well-known in the space launch community that the last time NASA really did something right was when Werner Von Braun was in charge of designing our rockets. When the Apollo program entered maturity in roughly 1969, the rocket system that was flying men to the Moon was a masterpiece. The Saturn V rocket brilliantly combined just the right combination of stages, engines, propellants and materials. That magic combination achieved the holy grail of rocket engineering never surpassed before or since. It threw more payload farther and faster and with a greater lift-off thrust than any other design with as little waste as possible. It was “optimal” for its mission. And the sky was the limit. Even bigger versions, designated “Nova” and based on the same design, were proposed for more ambitious space missions beyond the Moon. With the Saturn V putting 262,000 pounds into low Earth orbit (LEO), enormous space stations in orbit around the Earth seemed possible.
When Apollo 18 was cancelled and the last Saturn V was used to hoist the first space station, Skylab, into orbit, it was because of cost, and that’s nothing to be ashamed of. But since that time, rather than recovering its past glory and surpassing it, the space agency has suffered through a very long sophomore slump. It’s technical mojo has been tainted by the political influence inevitable when the Chief Administrator serves at the pleasure of the POTUS, and the budget is perpetually fought over in Congress. But there was even more evil afoot than politics. A sort of technical arrogance had taken hold at NASA that distorted engineering judgment. When the Space Shuttle was being designed, there was enormous pressure to do something “different.” The reusable “space plane” concept was popular, even if it had aspects that just didn’t make sense technically, and it won the day. Style over substance? Maybe. But the reusable space plane never lived up to its early promise, and that’s just a fact.
Perhaps the worst decision was to cut loose from the “archaic” Kerosene first stage of the Saturn and the enormous F-1 engines that powered it. Von Braun had purposely chosen the high energy-density Kerosene, or RP-1, propellant for the Saturn V first stage along with liquid oxygen as an oxidizer because the first stage had the biggest job to do. The enormous volume of the first stage propellant had to be minimized if the rigid structure of the stage, which was disposable and useless except to support the propellant, wasn’t to dwarf the weight of the whole rocket and ruin the performance. Kerosene was necessary for the first stage, and Von Braun knew it.
Why then was liquid hydrogen chosen to fuel the first stage of the Shuttle launch system? Did it make more sense for a space plane? Not at all. It doesn’t make more sense for any rocket. Hydrogen was chosen because it was thought, romantically, to be the clean-burning propellant of the future. Perhaps it was an early decision to “go green.” If so, it was ironic, because the decision made it necessary to supplement the thrust of the first stage with solid rocket boosters, and solids are among the very dirtiest of propellants, putting enormous amounts of toxic chemicals into the air with every launch. Good idea, huh?
But the worst aspect of the first stage propellant decision was weak performance. The Shuttle system in its various forms was only able to put between 40,000 and 50,000 pounds of useful payload into LEO. After the heady days of Apollo, this abysmal performance made the Shuttle a laughingstock in the industry. One would think that a lesson would have been learned, but a key aspect of the new SLS design is – you guessed it – a liquid hydrogen first stage based on the Shuttle design. Because, you know, we want to leverage that technology. Performance estimates of the initial configuration of the SLS put the payload to LEO at about 154,000 pounds. Remember the Saturn V number? It was 262,000 pounds. In 1965. If I may quote from Charlie Bolden’s letter above: “President Obama challenged us to be bold and dream big, and that’s exactly what we are doing at NASA with this new space exploration system.” Well, Charlie, I am so proud to be boldly going back to 1965 and only dreaming about half as big as my parent’s generation did. It takes real boldness to suck this bad and not be embarrassed about it. I just hope that your boss points that out in his next State of the Union speech.