Bill Phil

Don't know about RP-1, but syntin certainly is synthesized, and is slightly superior to RP-1 in a few ways. https://en.wikipedia.org/wiki/Syntin I can't find much on kerosene synthesis, but apparently there is a process to make it or something much like it using water and CO2. May be able to synthesize it with syngas as well.

Perpetual motion may have been a poor choice of words. Perhaps perpetual engine would have been better? Newton’s First Law implies “perpetual motion” unless outside forces act on an object. The problem is that perpetual has a few meanings.

Fried chicken

That has a lot to do with when the physics calculations are done, since updating the values requires calculations. If the game is chugging then updating after an interval may not be possible because the math hasn’t been done yet.

From my understanding the physics calculations are done based on frames.

I don’t think KSP is the best choice for a visualization... Sounds interesting. I don’t think he’ll read it, but it’s an interesting idea.

That’s certainly true. But even SLS could do more if it was building stations in LEO. Maybe something like a spacedock to build spaceships.

Heinlein put it right when he said that LEO is halfway to anywhere. That’s the real gateway to space. Once in LEO the energy to get to the vast majority of the solar system is less than the energy to get to LEO. I’d rather have a couple 70 tonne modules on a LEO station than a few small modules on a deep space station...

That isn't my argument. Nothing will be built if we keep the systems we have. NASA is a political football. It's not really going to do all that much for manned spaceflight without some serious political will. There's a reason that a lot of people think NASA shouldn't develop launchers anymore, but just payloads. SpaceX isn't the be all end all. Currently there's BO with New Glenn and ULA with Vulcan. Vulcan-ACES may even qualify as a super-heavy, depending on some things. Even if it's short of that margin, once operational both New Glenn and Vulcan will be capable of lofting tens of tonnes to LEO. Combining this with orbital depots (which need some serious development) would result in a better architecture than SLS/LOP-G for both Moon and Mars missions. Add in Falcon 9 and Falcon Heavy and there's some serious launch vehicle diversity in the near future, and some serious launch capability. If ULA can launch Vulcan-Centaur Heavy at a similar cadence to Atlas V that's 314 tonnes of potential payload (minus some margin for other extraneous stuff) in LEO, though most of that capability will likely go towards GTO/GEO launches. If New Glenn can keep up with Falcon 9 at 21 launches per year then that's potentially 945 tonnes per year. Falcon 9 could provide another 400 tonnes or so. Atlas V and Delta IV could add another few hundred tonnes. Even if those numbers are wildly off (they probably are, but whatever) and only some of the launches are used for NASA missions, that can still be more total mass in LEO than SLS can provide. Easily. And considering that Falcon 9 is already operational... The point is that EOR using commercial vehicles will probably be the best option moving forward. SLS was never needed for missions BLEO.

NASA isn't building that infrastructure. NASA is being ordered to do so, but they aren't doing it right now. As such there's a good chance it won't ever be built. And of course that infrastructure is impossible to build without SLS Block 1b unless NASA uses commercial vehicles or an electric delivery system. Block 1 just can't really build it. And SLS can't really do it even with Block 1b because the launch cadence will be far too low. LEO infrastructure can easily be multi-purpose and multi-functional. We need both LEO and lunar infrastructure for a comprehensive program. But the proposed LOP-G is not the kind of lunar infrastructure we actually need for extended lunar missions. LOP-G is just a station in a terrible orbit. It doesn't expand our capability. If it was planned to be equipped with a propellant depot that'd be something, but there's no indication that the plan calls for that, especially considering that the TRL of orbital depots is quite low. The point is that we need infrastructure. LOP-G isn't infrastructure. It's just a building in a hard to reach spot that provides no benefit. Double launch missions would work better, but of course SLS can't launch twice in short succession. We do not have the DST. The DST was originally planned with the DSG architecture, and even then it was just a proposal. More of an idea even. Heck, the DST is nowhere near as developed as dozens of other vehicles that have been studied and investigated over the history of NASA (and even longer), namely the DRA vehicles, but many others have been researched as well. The DST requires Block 1b if NASA will use SLS to launch it. And Block 1b may be cancelled (as it uses the EUS, we'll have to wait and see though). Even if DST is under development now (and I doubt it since the current administration is shifting focus back to the Moon) it will be under threat of cancellation every single year. LOP-G will be under threat of cancellation every year as well. We are not building deep space infrastructure and we do not have DST. We don't even have SLS right now... Block 1b can co-manifest 14 tonnes to TLI with Orion, and about 20 when going to L-2. In fact that was why L-2 was a good idea... but then someone decided to put LOP-G in NRHO...

There's no indication that such vehicles will ever be developed.

The math works out in such a way that it turns out to be way more efficient to launch to deep space from LEO than where LOP-G will be. The reason for this is the lack of deep space infrastructure. Of course investing in such infrastructure would change this dynamic, but considering that Mars missions are likely to be flags and footprints and occur at intervals of years... well it's not worth it for Mars. Maybe for the Moon, but again with a launch cadence of 1 every 2 years, or even 1 every year, you're not getting enough use to really justify the kind of deep space infrastructure we would need to really make in-depth lunar exploration practical. And of course you're not getting nearly enough launches to even build the infrastructure in the first place... though building it in LEO and sending it to deep space with an electric propulsion bus could work. Honestly that'd be a better way to build Gateway than SLS.

I was thinking rendezvousing the crew vehicle and the electric vehicle in a parking orbit above the belts and then continuing after everything’s checked out.

I keep thinking about an electric based mission architecture for the Moon and Mars... Could actually work. Which is the weird part. Obviously you wouldn’t put crew on it while it’s in the Van Allen Belts, but once it’s above them you can send the crew up and potentially even extra xenon or argon propellant. I ran some simulations in GMAT and found that a system with some decent power (acceleration of 0.3 milligees) can get to a C3 of 14.3 (the same as InSight) in 60 or so days from LEO. If the crew is sent up around day 40 or something they’ll only have 20 days to wait before they’re on a trajectory that can get them to Mars in roughly six months. Of course I haven’t run simulations for braking at Mars, but it shouldn’t be impossible. Still learning GMAT... The best part of this architecture is that you can bring a lot more payload with less propellant. The low thrust trajectories require more delta-v but as long as the ion engines have high isp you get away with less propellant, and if you’re clever, less total mass in LEO for a given mission payload mass. Potentially significantly less total mass. For a flags and footprints mission this kind of architecture probably outperforms most others. And if total engine runtime is relatively low the vehicle could even be reusable... Such an architecture wouldn’t need a superheavy like SLS, just something that can launch the biggest single piece - probably the lander. Even then it could potentially be launched empty, provided the technology and hardware for propellant transfer is developed. Yeah but it’s clear that this rocket is intended to stick around for decades like Shuttle. If NASA ever does do a manned Mars program SLS will be unfit.

I can’t believe it...

Both the Macon and the Akron crashed... So did Shenandoah. Luckily Los Angeles didn’t... If I recall the blimps used to monitor the coast used helium.

Which one? There’s the 8 million ton “colony ship” edition, the 10 thousand ton Outer System Expedition concept, the 4000 ton Mars concept, the Orion Battleship, the 8, 10, and 12 meter NASA designs, the 8, 10, and 12 meter USAF designs, the starships proposed by Dyson... There’s also mini-mag Orion. My favorite is the Medusa concept - instead of tossing a nuke behind you you toss one in front of you. Also it reminds me of Battletech jump sails, so of course I’m a bit biased...

Say what you want about Shuttle, but it did provide some capability that only one other vehicle provided (Buran). Of course that capability (specifically bringing satellites back from orbit) wasn’t used that often, but at least there was something it could be useful for. SLS is too small for Moon missions and too big to be practical. Even the Shuttle Program could maintain a launch cadence of something like 3 or 4 launches per year. But at least there were payloads for it. Right now the only payload for SLS is Orion, and maybe Europa Clipper (but that’s probably not gonna happen with SLS).

Check out astronautix. It has a bunch of stuff, including a list of Saturn V variants.

Yeah. The semantics of percent increase and percent probability are quite important.

I suspect part of the issue is throttle sensativity. That and the flames that creep up the side...

Well if Musk doesn’t give it up or let us down he might just get nuclear pulse to happen... in the 2030s. Also that meme is dead, man.

Only really need 6500 for Europa Clipper out of LEO.

I don't know... According to some guys at MSFC Ares V wasn't doing very well either. Some of the trajectory analysis was done making certain assumptions that turned out to be very inaccurate if not downright impossible. And with Orion growing in mass the EDS probably couldn't deliver both Altair and Orion to TLI. That said, NASA should've skipped straight to SLS Block II Cargo with 5 SSMEs on the core, which is basically a less powerful Ares V using SSMEs. 5 SSMEs would lower gravity losses (one of the biggest handicaps SLS suffers from - 4 SSMEs just don't give enough thrust to efficiently launch the stack). So with 5 engines it could potentially rival the proposed Ares V. Might have to deal with a smaller lander than the proposed Altair, though. Also I'm not sure about EUS's capabilities if a Constellation style mission was performed. If they do want to return to the Moon by 2024 that's going to require Block 1B at the least, Block 2 preferably. Block 1 should be cancelled (cutting losses on ICPS) and then either Block 1B or Block 2 developed, hopefully fixing some of the problems. However they'll also need a serious change in project management just to make it remotely possible. Lander development would need to start now, but they'd need to do mission analysis first to find out what exactly the lander would need to be capable of given limitations of SLS and Orion. If they can get away with a new SM with more delta-v for Orion that would be preferable as well. Of course all that is not likely to happen.