Hmm, that essay is interesting. But it has clear problems. One part that jumped out at me:
But to grasp just how far our current mindset is from being able to attempt innovation on such a scale, consider the fate of the space shuttle’s external tanks [ETs]. Dwarfing the vehicle itself, the ET was the largest and most prominent feature of the space shuttle as it stood on the pad. It remained attached to the shuttle—or perhaps it makes as much sense to say that the shuttle remained attached to it—long after the two strap-on boosters had fallen away. The ET and the shuttle remained connected all the way out of the atmosphere and into space. Only after the system had attained orbital velocity was the tank jettisoned and allowed to fall into the atmosphere, where it was destroyed on re-entry.
At a modest marginal cost, the ETs could have been kept in orbit indefinitely. The mass of the ET at separation, including residual propellants, was about twice that of the largest possible Shuttle payload. Not destroying them would have roughly tripled the total mass launched into orbit by the Shuttle. ETs could have been connected to build units that would have humbled today’s International Space Station. The residual oxygen and hydrogen sloshing around in them could have been combined to generate electricity and produce tons of water, a commodity that is vastly expensive and desirable in space. But in spite of hard work and passionate advocacy by space experts who wished to see the tanks put to use, NASA—for reasons both technical and political—sent each of them to fiery destruction in the atmosphere. Viewed as a parable, it has much to tell us about the difficulties of innovating in other spheres.
The idea here is interesting. But by the time the shuttle was already being designed there was some understanding of the dangers of space debris (although Kessler’s seminal work would not have been done for a few years). The problem of having very large objects in near optimal orbits would have been obvious. And since the shuttle flew at a fairly low orbit, one would actually have these deorbit and renter soon after launch anyways without giving them a massive boost. Spent fuel containers are also not optimal for later storage. They don’t have the same characteristics that one generally wants unless one modifies them massively. So even if one could boost them even higher for free, it isn’t at all clear you’d want them for construction without massive amounts of changes. Sure it might have been nice to have it as an option, but the main reason the shuttle didn’t succeed was that it had so many different jobs it had to do. For example, the military wanted it to be able to launch into a polar orbit and come back down after a single orbit.
This also doesn’t seem to appreciate at the time how incredibly innovative an actually reusable space plane was. It was perfectly reasonable in 1970 for this to be innovative. The fact that all the shuttle replacement proposals are basically copies of the shuttle or minor variants seems to be a much stronger argument that there’s a real problem.
The fact that all the shuttle replacement proposals are basically copies of the shuttle or minor variants seems to be a much stronger argument that there’s a real problem.
The space shuttle did not actually work—hence a new version that actually does work is the correct thing to do.
An actually useful space shuttle would be capable of frequent flights, say once a day, would not need crew to push the big button, and would land like the rocket it actually is instead of justifying NASA’s air force affiliation with a few seconds of normal flight like a plane.
Since it would fly once a day, it would necessarily transport smaller cargoes to space: There just is not enough demand yet. So it would be capable of carrying one reasonably slim passenger plus his life support. Larger objects would have to be taken up in bits an assembled in space by a robot.
The current proposals aren’t anything like this. They won’t be anything that could fly once a day. They aren’t proposing anything like that. The current proposed replacement will be able to launch if everything goes well slightly more frequently than the shuttle did. It won’t be nearly as replaceable (crew launch will be an essentially Apollo-style system). The total lift mass will be higher than the shuttle eventually but not for the early versions.
The main systems that are coming from the shuttle are the shuttle booster rockets, and it would have a similar external fuel tank. There’s no engineering reason for doing this. The primary reason is that certain contractors lobbied Congress so that they could keep their contracts for the parts they get to build. There’s a proposal to eventually give the SLS a new set of booster rockets that use more advanced technology and are built to actually optimize the new SLS requirements, but I’m skeptical that this will happen. And if it does happen, there’s only one guess about what company will make the new booster rockets.
This isn’t about taking a flawed plan, learning from it, and making a new version that doesn’t suffer from the old flaws. This is mainly about keeping the same small number of big aerospace companies happy.
Hmm, that essay is interesting. But it has clear problems. One part that jumped out at me:
The idea here is interesting. But by the time the shuttle was already being designed there was some understanding of the dangers of space debris (although Kessler’s seminal work would not have been done for a few years). The problem of having very large objects in near optimal orbits would have been obvious. And since the shuttle flew at a fairly low orbit, one would actually have these deorbit and renter soon after launch anyways without giving them a massive boost. Spent fuel containers are also not optimal for later storage. They don’t have the same characteristics that one generally wants unless one modifies them massively. So even if one could boost them even higher for free, it isn’t at all clear you’d want them for construction without massive amounts of changes. Sure it might have been nice to have it as an option, but the main reason the shuttle didn’t succeed was that it had so many different jobs it had to do. For example, the military wanted it to be able to launch into a polar orbit and come back down after a single orbit.
This also doesn’t seem to appreciate at the time how incredibly innovative an actually reusable space plane was. It was perfectly reasonable in 1970 for this to be innovative. The fact that all the shuttle replacement proposals are basically copies of the shuttle or minor variants seems to be a much stronger argument that there’s a real problem.
The space shuttle did not actually work—hence a new version that actually does work is the correct thing to do.
An actually useful space shuttle would be capable of frequent flights, say once a day, would not need crew to push the big button, and would land like the rocket it actually is instead of justifying NASA’s air force affiliation with a few seconds of normal flight like a plane.
Since it would fly once a day, it would necessarily transport smaller cargoes to space: There just is not enough demand yet. So it would be capable of carrying one reasonably slim passenger plus his life support. Larger objects would have to be taken up in bits an assembled in space by a robot.
The current proposals aren’t anything like this. They won’t be anything that could fly once a day. They aren’t proposing anything like that. The current proposed replacement will be able to launch if everything goes well slightly more frequently than the shuttle did. It won’t be nearly as replaceable (crew launch will be an essentially Apollo-style system). The total lift mass will be higher than the shuttle eventually but not for the early versions.
The main systems that are coming from the shuttle are the shuttle booster rockets, and it would have a similar external fuel tank. There’s no engineering reason for doing this. The primary reason is that certain contractors lobbied Congress so that they could keep their contracts for the parts they get to build. There’s a proposal to eventually give the SLS a new set of booster rockets that use more advanced technology and are built to actually optimize the new SLS requirements, but I’m skeptical that this will happen. And if it does happen, there’s only one guess about what company will make the new booster rockets.
This isn’t about taking a flawed plan, learning from it, and making a new version that doesn’t suffer from the old flaws. This is mainly about keeping the same small number of big aerospace companies happy.