25 thoughts on “A New Era For Space”

  1. Two quick observations

    1. Propellant depots are mentioned once and only once which I suppose is better than zero.

    2. Lots of discussion about nuclear thermal propulsion including FAA rulemaking for launches with nuclear thermal propulsion onboard. No mention of NRC licensing being required?

    The part about propellant depots indicates that commercial operators will construct and operate them in the future but appears to see no role for the govt in them.

    1. I guess you could say propellant depots do get mentioned more than once if you count terms like propellant refuelling but overall discussion on this subject is very vague.

      1. No reason to make the Chair of the Senate Appropriations Committee swell up and start agreeing with Nancy Pelosi about shutting down the government through no budget. That’s one possibility from talking too explicitly about government funding for depots, and I don’t see them risking that. That control of the funding funnel for spaceflight has been Shelby’s focus since he joined the senate as a Democrat in 1987. Purely LBJian in his politics, whatever Party he attaches to.

    2. –The part about propellant depots indicates that commercial operators will construct and operate them in the future but appears to see no role for the govt in them.–

      I think that is good idea.
      I had thought govt should build depot in LEO for LOX and once it demonstrated operational capability. thereafter it would be commercial thing.
      So I thought NASA should build LOX depot at 28 degrees, and use it for lunar robotic mission {and any robotic mission] and could be used for Manned Lunar mission.
      But it appears we are doing smaller scale robotic and manned program. And we could be gettng Musk’s Starship, which will function as way to refuel in orbit.
      Anyways, if there is mineable lunar water, I thought such commercial operation would need a depot in Low Lunar and it would be not be govt depot. And depots for Mars orbit likewise would commercially done. Or NASA would buy rocket fuel, and all NASA cares about is getting rocket fuel where and when they needed.
      But at this point, it seems NASA doesn’t have the time {or money} to build LOX depot in LEO.

      1. “But at this point, it seems NASA doesn’t have the time {or money} to build LOX depot in LEO.”

        And as long as refueling from propellant depots threatens production of SLS, NASA won’t have that money if Senator Shelby still breathes.

      1. Interesting. AST has sole licensing authority, but part of the licensing process is the payload review, wherein the rest of the government is invited to submit any objections within 30 days. I don’t recall if the NRC has ever been on the mailing list, but I’m sure they would be if anyone proposed flying a nuclear reactor. I would be willing to bet that the Sun would burn out long before a private company got a thumbs up from the NRC on a nuclear thermal propulsion system.

        1. The NRC would as it is would probably claim jurisdiction over RTG launches such as Mars 2020. To date as I understand it all RTG have come under NASA LSP authority not FAA.

          The report wants the FAA to undertake rulemaking specifically for nuclear thermal however, I wonder if the FAA even has legislative authority for. A nuclear thermal reactor would only start operation once an orbit but as Laura and many others have noted the FAA doesn’t have authority after stage separation.

          Another possibility is that the DOE like NASA and DOD has extensive OTA authority. Conceivable a private payload operate could pay for the DOE to construct and operate an in-space reactor the biggest problem is that DOE is well known for NOT engaging in OTA despite having the legislative authority to do so.

          1. Yes, I read this to the end. It’s quite extraordinary.

            FAA doesn’t have the technical depth to deal with nuclear anything. In fact, outside of AST, it hasn’t the technical depth to distinguish between “fuel” and “propellant,” and as for LOX…well, forget it.

            I note that they still are calling for streamlined launch licensing by the FAA. That was supposed to have happened by February of 2019, and still hasn’t. It won’t, either, because FAA has to use the most conservative “range” rules as it’s basic requirements, and has no mechanism to waive any of them. It’s an insoluble problem. As far as I know, no one has communicated that to the administration.

          2. My impression was the original proposed rules coming out of the FAA were beyond bad(as in actually a step backwards) and thus AST was sent back to the drawing board. I do get the general impression though that SpX has forced both AST and the ranges to get much more innovative. AFTS was talked about for years but only SpX went ahead and actually implemented it. Same with SpX and the FAA Space Data Integrator(which should go into production use sometime this fall). None of the other launch providers i.e. ULA, ATK etc ever seemed to have much interest in any of this outside of research labs.

          3. It was a number of years ago that NRC said it wouldn’t claim jurisdiction. The way I understand it NRC oversees commercial nuclear materials but doesn’t have authority in space. DOE oversees/supports governmental space missions.

    1. During my two years at ATK, I proposed setting up solid propellant depots in LEO. Star 48 and Castor 30 motors could be stockpiled in LEO for decades, and used in various combinations for any number of missions. It isn’t even difficult. But, of course, it got no traction.

      1. Michael without getting you into NDA problems how would you describe the ability of solid fuels to withstand the thermal cycling that occurs on every orbital pass? Any possible issue with explosive voids forming?

        1. It’s trivial to keep the temperature of a 4,700 to 30,000 pound solid motor constant with a 90 minute periodic change in sunlight. What is amazing is the durability of solid motors, which have been used in years-long missions and worked flawlessly.

          I’ve been in this business 40 years, and have no religious devotion to solids, liquids, or hybrids – but I know a great deal about all of them. Each has a place.

      2. In one of these threads I suggested that solids would be a simpler solution for the ascent engine of a barely-adequate Artemis re-usable lunar lander that has to rendezvous with the Lunar Gateway. They don’t require delicate plumbing or a sophisticated storage infrastructure.

    2. SpaceX still has to do the fuel transfer in LEO which I think is the harder problem than just storage. ULA is already claiming their Vulcan-Centaur coming as soon as next year will be able to keep cryogenic storage on station for months. The problem seems to be fuel transfer of cryogenic.

    3. SpaceX’s plan is to launch an “accummulator” tanker, refill that from other tankers, then refill the mission starship from the accummulator (minimizing the docking ops for the crewed vehicle). Technically that’s a depot, and there’s no reason for it to ever land again.

    4. But will every activity in cislunar space or around Mars be on a Starship? People point out how Starship could make a great fuel depot but hopefully, there will be a lot of different types of activity that could benefit from different types/sizes of depots.

      1. If the current move toward space doesn’t peter out like the last one, things like starship will wind up being thought of as landing craft, and interplanetary liners will be the big game. It’s starship now because you have to start somewhere. Anything smaller is a waste of time and money, and we might as well stay home. It’s the same with transportation on Earth in its end stage. Airliners are the thing. Anything smaller is a toy. On the sea, it’s ocean liners, tankers, and container ships. Sailboats and yachts are for fun. Space is not going to be different, if it’s to be anything at all.

  2. Tim. To get propellant into storage you have to transfer it. To get it out of storage you have to transfer it. To store it between times you have to store it. With the SpaceX approach you just transfer it. Seems to me like a depot is harder.

    1. But you still have to store it somewhere, even if its in the crewed starship. It will take a minimum of 5 tankers to refuel a starship, so the fuel is going to have to wait somewhere in orbit, for at least a couple of days (until there are more than just two SuperHeavy pads).

  3. DougSpace, great point. SpaceX has lots of experience transferring fuels both at the cape and at Boca. Probably the only wrinkle would be low gravity conditions.

    I could see them putting the transfer plant into a Starship parked in orbit, and then just send tankers up to refuel to any ship on the other side of the orbital plant.

    1. The seagoing analogy to what you’re talking about is an oiler (for surface ships) or a sub tender, perhaps. Just because it isn’t called a depot doesn’t mean it doesn’t do the job of a depot. Odds are high Musk knows this. Eventually, when we have interstellar liners, they’ll still have to be refueled. If we ever build space elevators, it’ll be to lift fuel to orbiting liners. In between “accummulator” starships and “fuel elevators,” maybe there’ll be an era of very large orbital fuel depots constantly topped up from whatever body they’re orbiting. I’ve also visualized the possibility of bringing fuel to depots via solar sail from places like Titan, taking advantage of the pipeline effect. It doesn’t matter how long it takes product to go from the wellhead to the gas station, as long as it keeps coming out of the spigot.

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