The Next Generation of Human Spaceflight

[93143]

you are assuming that NASA will not overrun the projected costs for the heavy lifter, which it most likely will by a large margin.

Other way around. The costs quoted for BFR and AVPII are from the companies that want to do them, and are IMO extremely likely to be low. They are also likely to not be full-wrap costs. On the other hand, my estimate for SDLV is based on the DIRECT estimate (but with a ballpark plus-up for costs Shuttle won't be able to carry any more, like the SRM production line). DIRECT is known to have used margins around 30% on average, and to have included the cost of test flights and so forth. Also the systems and processes for an SDLV are already known for the most part, whereas this is new territory for SpaceX...

Sure, NASA could still overrun; it's not even particularly unlikely. But I think either of the other two overrunning is actually more likely.

Also the operating cost of the shuttle and the future heavy lifter are what make this thing even more expensive. A huge standing army for a few flights a year is inefficient.

What makes you think a Shuttle-derived heavy lifter would have anywhere near the baggage STS does? I've seen an estimate that says Jupiter would need about 1/3 the workforce of Shuttle; most of the work is related to the orbiter. Not to mention that even STS has seen substantial efficiency improvements over the last decade or so...

Scale up SpaceX to deal with a BFR and you're probably talking the same ballpark. Even trying to scale up to being able to launch dozens of Falcon 9s per year would dramatically increase SpaceX's workforce.

That reminds me - the proper term is "workforce", not "standing army". They don't stand around sucking up cash; they do work. Supporting a super heavy takes more work than supporting a medium lifter (at comparable flight rates). Supporting a large, do-everything reusable spaceplane designed in the '70s takes more work than supporting a super heavy. Of course, you get capability for the extra work.

I know Shuttle is suboptimal, and I know SDLV is technically suboptimal. But (a) they aren't nearly as suboptimal as people tend to think, and (b) sometimes better is the enemy of good. And right now, it looks like SDLV is what Congress will fund.

[93143]

On the subject of racks, my source is here:

http://forum.nasaspaceflight.com/index. ... #msg671041

There's a bit of back-and-forth on the subject; read down a few posts...

[GIThruster]

I'm personally delighted Constellation is gone and soon so will be shuttle. If SpaceX and ULA can't provide I say we buy from those who can. I know this is heresy, but I also hope we never build a super-heavy of any kind. I don't think people think clearly when they think about super-heavies--all the new infrastructure that entails and really no significant benefit. We're quite capable of designing around a smaller launch vehicle and that's what we ought to be doing.

Why would anyone be convinced we need a super-heavy when there is no mission for it yet? Designing and building the launcher first is all backward. IMHO, what we need to do is design a reusable interplanetary explorer craft around today's launch solutions. Stop trying to do 6 things at once and just do one thing at a time. We need a craft that can fly from LEO to anywhere we'd like to go in our planetary system in reasonable (meaning fast flight) amount of time. Build half a dozen with modular design that can be continually upgraded and then fly them for decades. If you make the mission, this sort of "explore it all", then you know what to build. You can weigh options like super-heavy in light of what you're trying to do, which really needs to be a lot more than a jobs program.

[93143]

I'll handle this later. I need to get to work or there won't be much sleeping tonight...

[Skipjack]

The only reason they want the new heavy lifter to be Shuttle derived is so they can keep sending money to the same companies and keep the standing army in Florida employed. A shuttle derived heavy lifter is nothing but an expensive government jobs programme, with a low chance of success, a high chance of cost overruns and therefore cancellation at the next convenient opportunity.

[CaptainBeowulf]

In my view there are at least two missions for an SDLV:

1. Terrestrial planet finder telescopes. SDLVs have the launch shroud diameter and the mass to orbit capability to take up some pretty big arrays. Yes, you could design something much more compact and lighter that "unfurls" when it gets up there, but that way you introduce way more complexity while reducing robustness. The launch vehicle may cost less, but the telescopes will cost way more, and be more likely to fail.

2. Space station replacement. The ISS wasn't designed to last forever. An SDLV could either: (a) replace the current ISS with a much more robustly designed station (assembly from 70-80MT modules as opposed to the 20-30MT modules the shuttle carried). (b) Build a similar space station (20-30MT modules) at a Lagrange point between the Earth and the moon.

I would prefer (b), because in the time it would take to get around to building it (2020s), you could probably help the smaller commercial programs along to the point where they could build small vehicles (3 or so crew) capable of reaching it. It would then provide a way station to the moon, enabling resumption of moon exploration and a permanent moon base.

Commercial space would handle Earth to the Lagrange point, NASA would be in control of the Lagrange point to the moon.

Then, either the moon or the Lagrange point would make a good construction area for an interplanetary ship that could cycle between the Earth system and Mars every couple of years, enabling sustainable Mars exploration.

I would use the approach proposed by Zubrin back in the 90s to start a Mars base: launch a couple of automated modules there from Earth's surface using SDLVs. Ignore the fringe environmentalists and send a nuclear reactor on one. Once deployed on Mars, the nuke starts working and produces power for other mechanisms that do such things as create fuel from Mars' atmosphere. Once the computers report that the fuel tanks for the Mars assent vehicle are full, you can send the first crew.

The second module would have additional components for setting up a hydroponics greenhouse to grow food and some basic manufacturing capacity for small tools and replacement parts, extracting water and oxygen from the environment, etc.

Maybe shoot a few more automated modules directly from Earth's surface before starting your big ship shuttling from the Lagrange part to Mars orbit.

So, there would be a lot of potential missions for a SDLV. And if NASA turned over shuttling crews into orbit and launching small and medium payloads to commercial space, there would conceivably be enough money for these more far-ranging projects.

The last major argument for SDLV is to keep part of the current workforce in existence. If Shuttle shuts down and only small commercial things fly for the next decade, the workforce for supporting a heavy lift will have to be restarted from scratch. That will cost a huge amount of money if we ever realize that we need that HLV capability after all.

It would cost SpaceX or anyone else a gigantic amount of money to restart it in the 2020s - probably could only be done with government assistance, thereby turning them into state design bureaus.

I think it's better to keep it in existence, do some suboptimal earth-to-orbit missions with it initially just to keep it going - and then shift to Lagrange point/moon operations ASAP while getting SpaceX and others to do earth to orbit.

With HLV capability still in existence, it might be possible to start letting SpaceX and others use the infrastructure for their own HLVs in the 2030s - thus making it economically feasible for them to get into the HLV business.

After that, in the 2040s, NASA might get out of the launch vehicle business altogether and go into just designing interplanetary craft and space stations... hopefully by that point fusion-powered interplanetary craft, or at least high-powered VASIMR derivatives.

[kunkmiester]

I believe that the other advantage to a SDLV was that the tank production line is already up, and would take minimal modification to start producing the new tanks. Not sure how much that's worth though.

[CaptainBeowulf]

Yes, I've also heard that for whatever reason, structural modifications to the tanks to support weight on top, rather than on the side, are not massive.

I think the largest cost is the workforce, plus the launch infrastructure, such as the crawlers. The tanks are a large structural component though, and would be a significant fraction of the cost of the LV.

Also to be taken into account is that the vehicle assembly building, the tank transport barge, and the crawlers are currently set up to handle tanks of the approximately size that either the shuttle or a minimally altered SDLV have. One of the problems with Ares V was the decision to go for larger tanks (much longer AND also wider) - which required rebuilding all that other infrastructure.

There's also the idea of using the tanks to build space stations, which was put forward by space enthusiasts since the 1990s. I've never seen a good argument as to why it couldn't be done. The tank is pretty much carried into orbit anyway, is pretty much airtight, and doesn't seem to suffer much structural damage from launch or ascent (apart from shedding some foam insulation - but that doesn't compromise the metal substructure for reuse in orbit).

[GIThruster]

It would then provide a way station to the moon, enabling resumption of moon exploration and a permanent moon base. . .

. . .After that, in the 2040s, NASA might get out of the launch vehicle business altogether and go into just designing interplanetary craft and space stations... hopefully by that point fusion-powered interplanetary craft, or at least high-powered VASIMR derivatives.

I like the bulk of Beo's thinking but my trouble with it is that to do these things, NASA would need a $50 billion annual budget. This is the problem with most big space dreams, they don't manage the fact we don't and won't have such a budget in the future. Apollo is over. ISS is going to fly for at least the next 10 years and we have huge financial commitments to it (as well we should .) That doesn't leave money for things like a moon base, and why would we want a base when we've yet to see most of our home system?

IMHO, focus on the end game. Until we have something much better than rockets, we are stuck here in this planetary system. Lets explore it? That's a huge challenge with lots more to win than setting up a base, which will inevitably cost more than anyone will at first admit, and put the breaks on real exploration.

I think SpaceX can build a heavier lifter incrementally and care for launching larger stuff like James Webb. SeaLaunch is going to be competing and Zenit is a bit larger launcher than Falcon. ULA needs to stop playing public works program and invest in their own stuff to become competitive again, rather than simply monopolizing the entire defense launch industry and living fat off the cash. If any of these sorts of solutions work, then we have a working launch system here at home. (Quibbles about SeaLaunch aside.) If they all fail, people take their lumps and we hire out. I doubt that will happen.

If NASA gives up worrying about launch completely, and focuses on interplanetary vehicles now, we can move on to the bigger, better dreams we really want to see happen and inspire the next generation of scientists and engineers to think big. And really, that is THE biggest payoff the human spaceflight program has to offer, big hopes and big dreams. Thing is, to get them, we need to actually dream smaller and within a decent budget.

[kunkmiester]

James White wrote a book really early, can't remember hte name, but in the first couple of pages, he talks about the ship they're on, which is mostly made of plastic, so that cosmic radiation doesn't cause as much trouble. Foam would certainly suffice, and I recall being told a large, interplanetary ship would have a layer of foam a couple of yards thick for such shielding. anything at the L point would need it as well, or, as White wrote, people who aren't worried about having kids.

[CaptainBeowulf]

I remember reading about a NASA study concerning generating an electromagnetic field around a spacecraft that creates its own magnetosphere - and this was back in the late 90s.

Like the Earth's magnetosphere, the artificial spacecraft magnetosphere deflects a lot of radiation. The magnets for generating it should also weigh less than a lot of other shielding systems, except maybe for foam. And they leave a lot of the spacecraft's surface open for other stuff, like radiators and solar panels.

A follow up NASA study said that they realized that the magnetosphere would also work as a solar sail. If you made a powerful mechanism, you could actually push the magnetosphere out from the spacecraft over a large enough area that the solar wind would push it quite nicely. Obviously, such a design would be more robust than a delicate physical solar sail. It could also be switched on and off easily. So, you have both a propulsion system and a shielding system.

You could use this to travel outbound in the solar system. However, inbound you'd need fusion rockets, and you'd have to scale the magnetosphere way down so you're not being pushed out. So, you'd need a shielded area of the ship for the inbound trip.

I don't think anyone's worked out the details - I haven't heard about any further NASA follow-ups. But I think it would make a fantastic research project for someone in engineering or physics.

I really think we should pursue something along those lines for solar system exploration.

[Skipjack]

I dont think that you need an SDHLV to make a new spacestation. I would rather go with inflatable structures like Bigelow is building them. You can launch those on smaller launchers like the heavy version of the Falcon 9.
They are more robust than the ISS modules too.
Like GiThruster pointed out, NASA does not have the budget to do all the things anyway. They would have had to abandon the station in a couple of years, had they proceeded with Constellation. There simply was not enough money to do both.
Also, after countless (yes countless) failed and cancelled NASA- LV projects that produced nothing but cost and never produced anything but a pile of paper tall enough to build a tether to the moon with it, I have absolutely no confidence that NASA can do this.
The main reason why they are going for the SDLV is that it is the option that best maintains the status quo for a little longer. It will give ATK and the all the other shuttle facilities something to do for a little bit longer.
Thanks to the lobbyists in congress and senate, making sure that the expensive cost plus contracts keep going to the same people again and again, is all that the respective politicians are interested in. Senator Shelby even said it himself that he was so proud to have inserted language into the bill that would guarantee ATK to keep busy.
Of course since ATK is a defense contractor all the reps are all of a sudden for government pork projects.
I hate this, I really hate this! The porkers have been ruining the US space programme for decades and they keep doing it.
Obama saw that and he wanted to change it. The administrations plan was excellent! It would have done away with the pork, saved a ton of money and given a huge boost to the US space industry. Instead we once again get pork and more pork. Nothing will be done, nothing will change. I predict the US to buy launches from the Russians for the next 100 years and quite honestly that is what you guys deserve for this ruthless pork feast!

[Skipjack]

Worth reading:
http://www.transterrestrial.com/?p=31125

[choff]

Yes, I've also heard that for whatever reason, structural modifications to the tanks to support weight on top, rather than on the side, are not massive.

I think the largest cost is the workforce, plus the launch infrastructure, such as the crawlers. The tanks are a large structural component though, and would be a significant fraction of the cost of the LV.

Also to be taken into account is that the vehicle assembly building, the tank transport barge, and the crawlers are currently set up to handle tanks of the approximately size that either the shuttle or a minimally altered SDLV have. One of the problems with Ares V was the decision to go for larger tanks (much longer AND also wider) - which required rebuilding all that other infrastructure.

There's also the idea of using the tanks to build space stations, which was put forward by space enthusiasts since the 1990s. I've never seen a good argument as to why it couldn't be done. The tank is pretty much carried into orbit anyway, is pretty much airtight, and doesn't seem to suffer much structural damage from launch or ascent (apart from shedding some foam insulation - but that doesn't compromise the metal substructure for reuse in orbit).

I was told at one time that the fuel carried in the tanks was highly toxic, and because of this reuse was totally out of the question, seems like a terrible waste.

[TDPerk]

The fuels in the SSTS tanks are hydrogen and oxygen. Vent them for a little bit and they are gone.