Envisioning the world of 2100

[gturner]

I live in a house full of geologists, and none of them can come up with a minor consequence, much less a major one, because it just consists of pumping water, brine, sand, and other cheap stuff into rock strata that's already filled with water, brine, sand, and toxic sludge (aka oil and gas deposits) to fracture deep rock layers that already frequently fracture due to geologic forces. Most reserves are still found because the oil and gas is already leaking all the way to the surface through existing fractures.

Some worry about natural gas leaking into water wells, but water wells are so full of natural gas that well drillers have always treated them as natural gas hazards and cisterns have always been vented to prevent explosions.

 

[publiusr]

Now I seem to remember a mud volcano that might have been triggered by extraction. Earthquakes might actually be eased by lubricating faults to allow less tension to build up leading to greater quakes.

We are going to have fracking at some level.

Right now we get helium from natural gas wells, and we are running out of that.
Personally, I would support lawsuit protection to allow kids birthday balloons to be hydrogen. If a kid blows his face up--well, he can do that with Dad's Everclear just as well.

Helium must be had for cryogenic research, so we are going to have to use that and be able to get more, I hope. My position puts me at odds with Greens and conservatives in that I support drilling and market restrictions. So be it. The worst implement humans ever used against this planet is not the drill bit, but the plow.

Most reserves are still found because the oil and gas is already leaking all the way to the surface through existing fractures.

Very true--
http://discovermagazine.com/2008/jul/20-things-you-didn.t-know-about-oil

Most of Earth's oil has already leaked to the surface. Around the time of Deepwater Horizon, Wood's Hole found this:
http://www.whoi.edu/oilinocean/page.do?pid=51880&tid=441&cid=108012&ct=61&article=73106

And now the OTHER Sci-Tech poster shows up to push his pet philosophy.

There is no need to get ugly. I respect anyone trying to get industry off world.

You yourself have stated again and again that the aerospace industry is not very good at coordinating long-term plans...

The shuttle derived crowd has always been on the outside looking in--wanting something tried and true. Venture Star should have suffered the ire aimed now at SLS which is far simpler.

SLS...will never be profitable because it isn't designed to be profitable; it isn't the kind of thing that any serious businessman would try to build.

NASA shouldn't be run by businessmen--that was my point all along--or they would have bailed on Webb.

It isn't about profit man--that's your hang up.

HLV proponents are the ones capable of looking at the history of spaceflight, yet you come up with ad hom' arguements like these:

The kinds of people who want the SLS program are the kinds of people who have proven an inability to set coherent priorities for spaceflight (Griffin) people who want it for purely political reasons (Sen Hutchinson/Nelson) and people who simply can't conceive of any other way of doing things (Armstrong and Aldrin).

So I'm supposed to think your word is worth more than theirs? Hardly. Nelsons district will get space money no matter what rocket is used. EELVs--Delta IV anyway--are made in my home state, and I think a lot of Griffins priorities of simplifying spaceflight without as many Rube Goldberg space assembly missions by using larger LVs

Which ignores the fact that the United States does not need the mission capability provided by the F-35

We agree on that at least.

****************************************************************

Um, that's idiocy nested several levels deep...

That wasn't the arguement I was making mind you, that was the letter writers.' From what I understand Falcon can fly depressed trajectory in addition to having engine out capability, so it is number one in my book. My concern is that a lot of negativity that Ares/ Constellation faced (and that SLS faces now) will be turned against Musk. You have to know where the arguement is coming from. But this is how it starts. I recognized the letter writers name because--if you keep up with the trades, you see a lot of the same names: Sietzen, Lyles (Lester and Doug) Sega, etc. I'm worried that Musk may be facing more hit pieces in the near future.

The RD-180 uses a mixture ratio of 2.7:1, but it makes the pre-burner difficult to make because it has to run in a high temperature oxidizing environment.

And if there is one thing you want to avoid, its hot oxygen. From what I understand, RD-180 is the two nozzle half-strength version of the Zenit first stage/Energiya strap-on's RD-170 series engine of Glushko. He liked hypergolics but wanted time to perfect kerolox designs and Korolev [sic] pushed him, leading to the falling out--among other things (Kolyma).

Now from what I understand, the hydrogen engine equivalent to SSME was the RD-0120, which never had the burn through trouble that Glushko had with the RD-17X series, yet he didn't like the idea of the Energiya having hydrogen.

To me, that is not a problem in that hydrogen's trouble of having low density and high volume just leads to a wider HLLV shroud and all the advantage that comes with that.

Delta IV to me is the worst rocket. It is unwieldy compared to Atlas or even Falcon, yet not really big enough to use hydrogen effectively as opposed to an Energiya/ET/SLS/Ares V type design.

On the subject of Falcon's recent anomaly:
http://www.youtube.com/watch?feature=player_embedded&v=y6zsZiVa998

I'm a big believer in engine-out capability--and this proves that a failure in a densely packed aft section need not lead to fratricide. Now I understand that Musk wants to move the engines out around the outer 'rim' of the rocket. I wonder if that might actually make things worse.

When you have engines close together, I would think you would have a venturi effect where any debris would get entrained into the engine exhaust and be hurled downward and away.


I wonder if you widen the area between engines--that you might introduce a stagnant zone that might allow debris to have a more sideways ejection. Any thoughts about that?

 

[sojourner]

Musk is not "moving the engines out to the rim". SpaceX is changing the arrangement from 3x3 to an octagonal arrangement with one in the middle. The new arrangement provides a little more range of movement for the central engine to gimbal while also utilizing a more efficient thrust structure and eliminating the need for the 4 outer fairings.

Technically, they are pulling the 4 outer engines in.

 

[gturner]

Um, that's idiocy nested several levels deep...

That wasn't the arguement I was making mind you, that was the letter writers.' From what I understand Falcon can fly depressed trajectory in addition to having engine out capability, so it is number one in my book. My concern is that a lot of negativity that Ares/ Constellation faced (and that SLS faces now) will be turned against Musk.

It won't matter to him. In "The Avengers" we saw how much Iron Man cared for the opinions and objectives of SHIELD, and as even Robert Downey Jr. admitted, Elon Musk is Tony Stark.

The RD-180 uses a mixture ratio of 2.7:1, but it makes the pre-burner difficult to make because it has to run in a high temperature oxidizing environment.

And if there is one thing you want to avoid, its hot oxygen. From what I understand, RD-180 is the two nozzle half-strength version of the Zenit first stage/Energiya strap-on's RD-170 series engine of Glushko. He liked hypergolics but wanted time to perfect kerolox designs and Korolev [sic] pushed him, leading to the falling out--among other things (Kolyma).

Yes, the RD-180 is a half-RD-170. Interestingly, the RD-170's higher specific impulse compared to the F-1 means a Saturn V with 4 RD-170's would outperform one with five F-1's.

To me, that is not a problem in that hydrogen's trouble of having low density and high volume just leads to a wider HLLV shroud and all the advantage that comes with that.

If we had a high power RP-1 engine (like the RD-170 or Musk's 1.8m lbs proposal), they could use the SLS first stage as a second stage, ala Saturn V on steroid. The configuration they have now is a Shuttle-derived version of North American's Saturn II INT-17 proposal, which strapped Titan SRB's to the Saturn S-II stage, with an S-IVB on top, to give them a payload capability in between the Saturn IB and Saturn V.

I'm a big believer in engine-out capability--and this proves that a failure in a densely packed aft section need not lead to fratricide. Now I understand that Musk wants to move the engines out around the outer 'rim' of the rocket. I wonder if that might actually make things worse.

It should improve the mass ratio because the force will be more in line with the load-bearing skin, and it should also increase stability at the expense of slightly more base drag.

I'm not sure the seperation would have much affect on debris, but you shouldn't have birds nesting in there anyway.

 

[Crazy Eddie]

The shuttle derived crowd has always been on the outside looking in--wanting something tried and true. Venture Star should have suffered the ire aimed now at SLS which is far simpler.

Except that, unlike the SLS, Venture Star was actually a pretty good idea. The only complicated part of the venture star was the composite propellant tanks that NASA couldn't get to hold integrity under full propellant loading.

That, ironically, is what Venture Star and SLS have in common: both include features that were inserted for political reasons, and otherwise aren't in any way necessary for the system's development.

NASA shouldn't be run by businessmen--that was my point all along--or they would have bailed on Webb.

You say that like it's a bad thing.

It isn't about profit man

If we ever plan to get serious about expanding humanity's reach into space, it needs to be. We need to sort of grow up and admit to ourselves that the real world isn't like Star Trek, and the people who are going to make the biggest breakthroughs colonizing the final frontier aren't going to do it for free. SOMEBODY has to pay for it. It does not have to be taxpayers (not exclusively, and eventually not at all).

HLV proponents are the ones capable of looking at the history of spaceflight

The ENTIRE history of spaceflight includes less than a dozen flights by HLVs of any kind. One of those HLV flights deployed a space station whose life was cut tragically short by the lack of a mature spaceflight infrastructure in its country of origin.

That history ALSO includes eight space stations whose modules, crews and supplies were launched by much smaller vehicles. It also includes two whose modules were deployed by smaller rockets and were assembled in orbit with the help of orbiting vehicles. It includes four successfully developed cargo vehicles designed to launch on medium-lift rockets, and a fifth soon to fly in the near future. It includes the Mercury and Gemini programs, and more than forty years of consistent service by the Soyuz, and it includes the Shenzhou program and the in-development Tiangong modules.

HLVs have proven useful in one and only one application: the ability to launch an extremely small expedition to the surface of the moon with a very short development schedule. In other words, an HLV is exactly the kind of rocket you need if you want to beat your political rival in a space race.

So do we need to beat China to a near earth asteroid? Is that what's going on here?

So I'm supposed to think your word is worth more than theirs?

I couldn't care less who YOU believe. There is a lot of interesting work being done right now on spaceflight architecture and launch systems that will, over time, evolve into the kind of infrastructure we will need to really expand into space. HLVs will not be part of that infrastructure, and if NASA is forced to spend the entire bank on the SLS, they won't be part of it either.

Nelsons district will get space money no matter what rocket is used.

But not nearly as much, and not a guaranteed supply if private contractors are competing for reduced costs and increased capability.

I think a lot of Griffins priorities of simplifying spaceflight without as many Rube Goldberg space assembly missions by using larger LVs

Which is idiotic, because both NASA and the Russians have been using the "rube goldberg" technical for forty years and it has worked every single time; it has been proven to be cheaper, easier, more efficient and less dangerous. The singular disadvantage is that is SLOWER, which is only a disadvantage if you're in a hurry. And while the Mike Griffins of the world are happily "simplifying" spaceflight by forcing larger vehicles into production, who's going to be carrying crews and supplies to space stations in Earth Orbit? Who's going to be servicing the Hubble or its successors? Who's going to reboost the ISS or its successors when its orbit begins to decay? Who's going to send parts and equipment to repair those stations/satellites/telescopes when something unexpected happens to them?

All I know is, there is an American space craft in orbit right now, and it wasn't launched on an HLV.

SPEAKING of the history of spaceflight, HLVs have a considerably lower success rate, especially in light of the Polyus fiasco and the near-failure of Skylab.

Speaking more of the history of spceflight, I was recently reminded that the original Atlas rockets -- the very systems from which the current expendable launch vehicles evolved -- were instrumental in the Mercury program. Strictly speaking, EELVs have a more important place in that history than HLVs ever will.

 

[publiusr]

Except that, unlike the SLS, Venture Star was actually a pretty good idea.

No it wasn't--and it wasn't just because of the tanks--not that hydrogen likes multi-lobed composites. LH2 likes big roomy metal tanks better. Those are heavier so it makes sense to scale them up. For SLS, it doesn't have to have a TPS. Not everyone was a fan of aerospikes or that lifting body design. The opening credits of the SIX MILLION DOLLAR MAN aren't the only reason why folks are skeptical of lifting bodies. The heavy engine ramps are what demanded lightweight tanks to begin with.

First Venture Star had an internal cargo--then a hump--then external payloads and then wings attached. http://www.spaceandtech.com/spacedata/rlvs/venturestar_sum.shtml
http://www.nasaspaceflight.com/2006/01/x-33venturestar-what-really-happened/

Some comments on X/33 from the web:

"NASA chose the Lockmart design because it was the technically most ambitious. Facepalm."

That's Dan Goldin--the Anti-Griffin for you.

"The Venture Star based on the X33 was completely out of hand anyway. They could not get the weight under control and the lifting body design sucked so they made the wings bigger and bigger with every design iteration (since they also HAD to have the crossrange for some insane reason). That added even more weight and in the end the payload module had to be in a pod that would piggiback on the actual vehicle. It was a complete mess and the much less powerful SSMEs would have made things even worse...Both the Venturestar and the X-33 have tanks so large that it is not practical to put them in an autoclave, so composite design that does not require an autoclave is required."

"Everyone was laughing about it before it got cancelled." Everything said about SLS is true for that concept. This would have made more sense http://www.astronautix.com/graphics/x/x33rock.jpg

Heck, DC-X would at least give us Mars Landing tech. Venture Star was an abomination--and that just to go to LEO only. Venture Star would also be comparable in cost to SLS--probably much more expensive. Now if you want to prove to me that private initiative is better than public efforts, then show me a private firm that will make Venture Star work. I'm waiting.

If we ever plan to get serious about expanding humanity's reach into space, its to be. We need to sort of grow up and admit to ourselves that the real world isn't like Star Trek, and the people who are going to make the biggest breakthroughs colonizing the final frontier aren't going to do it for free. SOMEBODY has to pay for it. It does not have to be taxpayers (not exclusively, and eventually not at all).

Now I think that is naive on your part. The days of one guy inventing something in a back workshop are giving way to Big Science like Large Hadron, Hot fusion etc. You are one of the alt.spacers who just doesn't get it that spaceflight is more TVA than MSN

The ENTIRE history of spaceflight includes less than a dozen flights by HLVs of any kind. One of those HLV flights deployed a space station whose life was cut tragically short by the lack of a mature spaceflight infrastructure in its country of origin.

That country sustained a bunch of de facto HLVs in over 100 STS launches with orbiters. It can support an SLS without the orbiter fine.

That history ALSO includes eight space stations whose modules, crews and supplies were launched by much smaller vehicles.

Mir is hardly something I would want to do time in.

Shuttle was hardly small. Its very mass allowed stability for construction to begin with--the dog was still wagging the tail. A small number of SLS launches and ISS would have been finished. ISS

HLVs have proven useful in one and only one application: the ability to launch an extremely small expedition to the surface of the moon with a very short development schedule.

Which means that with proper development and constant STS type support, it can allow heavy Moon bases to be supported. Saturn-had it been allowed to continue--would have extended human presence beyond LEO. STS killed that. Time to go back to what works and stick with it. If reusibility and cheap access to LEO is that important--let Musk do that part.

HLVs will not be part of that infrastructure.

That is premature to say at this point--and if HLV doesn't work--it will be because of naysayers who try to get it killed to get at its funding.

"And while the Mike Griffins of the world are happily "simplifying" spaceflight by forcing larger vehicles into production, who's going to be carrying crews and supplies to space stations in Earth Orbit?

Let Musk do that. I'm not saying Musk has no role. Musk for LEO, SLS for BEO.

SPEAKING of the history of spaceflight, HLVs have a considerably lower success rate, especially in light of the Polyus fiasco and the near-failure of Skylab.

The Polyus failure had nothing to do with Energiya--that was the failure of the TKS ferry/FGB tug--like what was used to service Mir--those small modules you go on and on about, remember? The angry alligator agena was a worse failure than Skylab, but no one blamed the launch vehicle did they?

Strictly speaking, EELVs have a more important place in that history than HLVs ever will.

That is what ULA is hoping for. They want to kill SLS and Falcon so they can dominate the market and keep a monopoly.

 

[sojourner]

I give up. He's just too determined to have a Big Shiny Rocket as opposed to getting things done.

 

[publiusr]

Saturn V got things done. Venture Star was the waste of money. That was the shiny distraction.

 

[sojourner]

Saturn V is a museum piece. SLS is your BSR.

 

[gturner]

Venture Star was an engineering program to find out if SSTO was quite within reach with liquid hydrogen, because the liftoff weight of an SSTO is extremely sensitive to ISP and engine thrust to weight ratio. It wasn't.

There are some odd propellant combinations that could make an SSTO feasible, but they're not either ready, usable (toxicity), or cheap. Li3AlH6, for example, has slightly better ISP than LH2 and the same density as water (1.0), but the lithium would mean the fuel would cost $100 to $150 a gallon.

There are perhaps other options to make an SSTO feasible, like greatly increasing the Earth's rotation rate to impart a much higher initial horizontal launch velocity, but that would also benefit cheaper multi-stage rockets, making the SSTO face stiffer competition while the 3 or 4 hour day/night cycle would stretch out development schedules.

It is interesting to compare SLS to Saturn II, which would've used essentially the same technology and configuration (INT-19 included engines that are the direct forerunner of the RS-25's on the SLS), but had a 33-foot tank diameter instead of 27.5 feet, giving it 44% more fuel per foot of stack height than the SLS. For big lift, the 1966 design, a downgrade of an earlier 1960's design, wins!

 

[publiusr]

Heard much about Boron slurry fuels? I would think those are pretty dense. I also keep hearing about Nitrogen 20--supposedly a high pure element explosive. I have heard of China Lake 20, but I don't think it is the same.

 

[gturner]

I've heard of Nitrogen 5+ and that potentially there's higher molecular weight nitrogen compounds that would make good monopropellants, but they haven't even been able to make a 6 member nitrogen ring. There are some nitrogen versions of cubane that look interesting, though. CL-20 is being looked at as a solid fuel additive (and explosive, of course). However all of these would have the severe drawback that they're high explosives and very expensive to manufacture and store.

Getting back to the SLS, the design has inherent limitations from the requirements to keep the same people building the same things. At what point in the SLS program will someone ask if using the same basic SRB for 50 years is the opposite of cutting edge? The core stage is already over 200 feet tall (due to using a narrow tank diameter for heavy lift). Add a second stage and a little capsule (the Block II Crew configuration) and it's 385 feet tall (22 feet more than a Saturn V). The minimum height of the crawler is 20 feet, so the capsule configuration only clears the top of the VAB door by 60 feet.

Needless to say, the SLS will never launch anything really long like a huge space-station section because a low-density first stage and narrow tank diameter has already constrained the growth potential to the Saturn V class of HLV, capable of putting two men on the moon and returning them safely to Earth, but still not enough to send up deep-space missions in one shot. That would be okay if the SLS had a high flight rate and low cost where you could spread a mission across half a dozen launches, but the SLS won't have a high-flight rate nor a low cost.

 

[Crazy Eddie]

If we ever plan to get serious about expanding humanity's reach into space, it needs to be. We need to sort of grow up and admit to ourselves that the real world isn't like Star Trek, and the people who are going to make the biggest breakthroughs colonizing the final frontier aren't going to do it for free. SOMEBODY has to pay for it. It does not have to be taxpayers (not exclusively, and eventually not at all).

Now I think that is naive on your part. The days of one guy inventing something in a back workshop are giving way to Big Science like Large Hadron, Hot fusion...

... and SpaceX, and ULA, and Bigelow Aerospace, and Sierra Nevada, and Blue Origins. These are companies that are running world-class space programs with a tenth the budget and the technical overhead as their government counterparts.

And that is a trend that is not going to be reversed. Private companies will become more and more prolific in space over time; the only question is when and to what extent their capabilities will overtake those of NASA. Even if the SLS still keeps NASA ahead of the game, it won't KEEP them there for any amount of time. Sooner, rather than later, NASA is going to have to depend on the capabilities of those private operators even to sustain its BEO operations. They can either jumpstart that process by subsidizing and catalyzing the development of a spaceflight industry, or they can try one more time to make space exploration work using 1970s technology. In the former case, commercial operators will probably take over both LEO and BEO operations within the next twenty years; in the latter case, the next 40 years. Considering the private sector has proven far more innovative and far less sensitive to political brinksmanship than NASA has, which would YOU prefer?

That country sustained a bunch of de facto HLVs in over 100 STS launches...

... during which time the shuttle had a wide variety of uses and mission roles that 1) it performed at ten times the expense of a conventional launch system and 2) it eventually phased out -- one after another -- for safety reasons.

The shuttle was cool and all, but it doesn't change the fact that the STS was based in the first place on a set of fundamentally flawed assumptions, NONE of which have been borne out in practice. It's successor has effectively replaced a small number of those flawed assumptions with handwaving and politics.

The simple fact of the matter is the STS had no reason to exist without the shuttle orbiter to justify it. WITHOUT the orbiter, STS doesn't make any technical or economic sense; even NASA turned its back on the Shuttle-C, for precisely that reason.

Mir is hardly something I would want to do time in.

A dizzying number of scientists -- and more importantly, governments -- would disagree with that sentiment.

And the Russians, IMO, are missing out on that market. If they could just beef up their Soyuz production, Roskosmos could build and operate a new Mir-style space station in Earth orbit and lease it to India, Japan, the EU, the UK, Israel, Brazil, anyone and everyone who's ever expressed an interest in conducting space science but couldn't afford to use the ISS (or didn't want to wait in line).

Roskosmos, arguably, isn't really in a position to pull this off in an efficient way, but given enough time -- not a whole lot either -- some private companies will inevitably attempt exactly this. One of them, sooner or later, will succeed.

Shuttle was hardly small. Its very mass allowed stability for construction to begin with

The Russians didn't have a shuttle when they built the Mir. And China has no plans to develop one for Tiangong-2.

Speaking of the history of spaceflight...

A small number of SLS launches and ISS would have been finished.

Kinda like how Skylab was deployed with a single Saturn-V launch and was operational immediately on entering orbit.

Wasn't it?

Saturn-had it been allowed to continue--would have extended human presence beyond LEO.

What do you mean "would have"? It DID extend human presence beyond LEO. Then it was cancelled.

So what's gonna happen to NASA if Kay Bailey Hutchinson and Ben Nelson have a really bad election year?

fThat is premature to say at this point

No it isn't. Anymore than it was EVER premature to say that of the Saturn-V or the space shuttle. It is, in fact, even more true of the SLS, which little more than the bastard child of BOTH systems, rehashing the same 1970s technology in an explicit attempt to restore the mission capabilities that NASA was barely able to sustain in the 70s.

Let Musk do that. I'm not saying Musk has no role. Musk for LEO, SLS for BEO.

That's the problem, dude: there's no coherent plan to DO anything beyond Earth orbit!

Saturn-V was developed because President John F. Kennedy stood in front of a crowd and said "We choose to go to the moon! Not because it is easy, but because it is hard!"

SLS is being developed because some senator most people have never heard of stood in front of a crowd and said "We choose to build a really big rocket! Not because it is affordable, but because it is expensive!"

We're not talking about the usefulness of Shuttle-C anymore; that ship has sailed. We're not talking about the theoretical usefulness of HLVs -- ANY type of HLV -- to space infrastructure process; that's a more nuanced discussion, and the Falcon Heavy will eventually render it moot. This about the SLS being a really stupid thing for NASA to be spending money on, aiming for BEO, when they don't even have their shit together when it comes to LEO. That's like a country trying to build an aircraft carrier when their navy consists of two canoes and a rubber ducky; what's more, the ONLY reason they're trying to build an aircraft carrier is because they want to give the steel workers something to do.

The Polyus failure had nothing to do with Energiya

Part right. Specifically, it had to do with the fact that Polyus was fucking enormous, and was so Energiya, and therefore there wasn't much that could go wrong with the launch that wouldn't doom the entire craft.

Putting a space station into orbit using an HLV is a bit like trying to transport a car by firing it out of a cannon. It's a testament to the engineering prowess of NASA that they were able to pull it off at all... prowess that, that the current date, they no longer possess.

The angry alligator agena was a worse failure than Skylab, but no one blamed the launch vehicle did they?

More importantly, no one cared. Because Agena was cheap, and easily replaceable.

Strictly speaking, EELVs have a more important place in that history than HLVs ever will.

That is what ULA is hoping for.

Not hoping for, that's just the way it is. HLVs simply don't have the work history to justify the kind of money NASA has been ordered to spend on them, even if they had a coherent plan for how to USE them, and they don't.

 

[gturner]

Not hoping for, that's just the way it is. HLVs simply don't have the work history to justify the kind of money NASA has been ordered to spend on them, even if they had a coherent plan for how to USE them, and they don't.

I just did an interesting first pass calculation based on an Apollo mission using lithium aluminum hexahydride/H2O2 instead of Aerozene-50/N2O4.

http://www.sps.aero/Key_ComSpace_Ar...c_Propellants_for_Hypergolic_Applications.pdf

With a 500 psi chamber pressure it has a vacuum ISP of 469, whereas everything above the S-IVB on Apollo had an ISP of 311 to 314.

Holding the dry mass of the lunar ascent module, descent module, command module, and service module consant would still result in a required LEO mass of 57 tonnes, instead of 130 tonnes. Using it the 3rd stage would reduce that stage's dry weight, too, meaning you'd only need one launch on a Falcon 9H to fly the same mission.

 

[Crazy Eddie]

^ That's exactly the problem: everyone's talking about NASA repeating its previous achievements, essentially a reboot of the Apollo program; the thinking is that NASA went the wrong direction AFTER Apollo, so what we need to do is time travel back to 1974 and make NASA turn left instead of right.

The truth is, that kind of mission was never going to evolve into anything else. Apollo's goal wasn't to colonize the moon or setup long-term habitation. Apollo's goal was to BEAT THE RUSSIANS TO THE MOON. That it was allowed to continue on and do some useful exploration afterwards was just the icing on the cake.

We don't need more Apollo missions. We don't need a new Saturn V, a new CSM, a new LEM or a new SIVB. What we need is a robot transfer vehicle with an ion engine or something that can run supplies from the Earth to the moon; we need a permanent space station that can receive those supplies and coordinate with expeditions on the surface, and we need a fleet of small surface-to-orbit transports that can shuttle people and equipment back and forth from that station to the lunar surface. We need a VASIMR-equipped space tug that can get crewed vehicles to lunar orbit in three or four weeks, and we need cheap and efficient space taxis that can take people to those vehicles and carry them safely back home again.

In other words, we need a Trans-Lunar Railroad. It's going to take ALOT of rockets to build that, a lot of hardware put into orbit and tested in situ. It's going to cost a lot of time and money and maybe even lives. Which means what we REALLY need right now is not a racing stallion, but a workhorse.

 

[gturner]

^ That's exactly the problem: everyone's talking about NASA repeating its previous achievements, essentially a reboot of the Apollo program; the thinking is that NASA went the wrong direction AFTER Apollo, so what we need to do is time travel back to 1974 and make NASA turn left instead of right.

I'm not saying we exactly repeat Apollo, because too many of the original members are old or dead. But many of their grandchildren could be trained to fly and are already computer literate! There are even Von Brauns still around who could handle the design work, and we could find a surviving Kennedy to announce it a few months before he skiis into a tree or crashes a plane or something.

I'm just pointing out that an HLV isn't required even to exactly repeat Apollo if we switch to a better storable hypergolic, and SLS/CEV seems to be an Apollo rehash without enough funding for the lander - or much of anything else, either. A Falcon 9H version would only cost a couple hundred million a mission instead of a couple billion, while leaving enough funds available to actually build a base, an infrastructure, and start processing fuel.

The Li3AlH6/H2O2 (O/F ratio 0.7) is interesting, as lithium is in some moon rocks at 70-150 ppm and aluminum and oxygen are of course everywhere in abundance. Hydrogen is the problem with lunar fuel, and this fuel gives a 4% better ISP than LH2/LOX, doesn't require crygenic storage, is hypergolic, has a density of 1.0, and uses only half as much hydrogen as LH2/LOX. That might help make both lunar fuel and give us smaller, lighter fuel depots.

 

[Crazy Eddie]

If we're talking in-situ fuel processing, I would advise against any system that depends on hydrogen; the lunar base is going to need large amounts of it in the form of potable water and possibly as reactant in fuel cells during the long lunar nights.

For one thing, the vehicles that lift off from the moon aren't going much of anywhere else for a long time, so some sort of cheap and efficient monopropellant -- thermite based, probably -- would be ideal. Space craft going TO the moon could use hydrogen as a fuel, but by the time you start having three or four or five hundred people living up there, you're going to be sending such large vessels that chemical propellants are out of the question anyway and they'll be using ion trusters and/or VASIMRs for that (we ARE trying to project towards 2100, right?)

So, turn of the 22nd century: here's our LEO transfer vehicle. Cargo vehicles would be needed as well; both would dock with a large cruiser, something similar to the Nautilus-X, which would spiral out of Earth orbit to reach the moon three weeks later. The cruiser would rendezvous with small transfer vehicles launched from the moon's surface which carry the supplies and personnel back down to the surface facilities that need them.

Ideally, the lunar vehicles would be self-contained ascent/descent stages with a modular compartment; if you're sending supplies, you send a whole MPLM-type module that the LTV can carry down to the surface, the crews unload the goodies and then bolt some furniture to the walls so the empty container is now a new building. If you're sending crew, you have the surface outposts add a personnel carrier to the top of the ascent stage for the trip up and down; that would need to be shipped to them after they setup the base, but fortunately you would only have to send it once, and eventually the lunar facilities would develop the ability to build their own.

HLVs might be required to build those Nautilus-X style cruisers -- though I doubt it. Otherwise, the cargo modules and personnel carriers can be launched from Earth using conventional medium-lift rockets in the Ariane 5 or Falcon Heavy class (crewed vehicles would need an even smaller craft; a Dragon Rider or 2100 equivalent could be launched from a fairly small rocket, or the larger "supercaspule" publiusr likes could ride a Falcon Heavy).

 

[gturner]

I agree that we'll go VASIMIR, perhaps after ion thrusters for the Earth-Moon supply deliveries, and then eventually eliminate the chemical thrusters for lunar ascent/descent and go with electromagnetic launch and recovery, if not something even stranger like rotating orbital cables and such.

But to get to that point, crewed lunar vehicles are going to have to get a lot cheaper and more frequent than the SLS can manage under any projection, and if something like the Falcon 9H with flyback boosters works, its launch cost will drop to that of the regular Falcon 9 or even much lower, and with a high ISP alternative it could probably do lunar missions with a crew of three or four to the surface as cheaply as the current ISS resupply flights, which we know current and projected budgets can support.

One simple lunar fuel I don't think anyone has looked at is molten aluminum/LOX. If the tank and piping are pressure-fed titanium or stainless steel with heater elements and ceramic aerogel insulation, it wouldn't be a very big deal to make such a craft for lunar ascent, though it might need to run very oxygen rich to keep chamber temperatures manageable.

 

[Crazy Eddie]

I agree that we'll go VASIMIR, perhaps after ion thrusters for the Earth-Moon supply deliveries, and then eventually eliminate the chemical thrusters for lunar ascent/descent and go with electromagnetic launch and recovery, if not something even stranger like rotating orbital cables and such.

Chemical rockets actually work perfectly well for those short range surface-to-orbit runs, considering they're likely to be a lot cheaper and safer than any of the more exotic alternatives. To suggest otherwise is almost to imply that people in Chicago should stop driving cars just because the L-train was invented; that's an overly simplistic view of how commerce actually works.

But to get to that point, crewed lunar vehicles are going to have to get a lot cheaper and more frequent than the SLS can manage under any projection, and if something like the Falcon 9H with flyback boosters works, its launch cost will drop to that of the regular Falcon 9 or even much lower, and with a high ISP alternative it could probably do lunar missions with a crew of three or four to the surface as cheaply as the current ISS resupply flights, which we know current and projected budgets can support.

Maybe, but I'm actually thinking that you could start small with a group of four craft, scaled-down versions of the Nautilus-X as command modules for some of those earlier expeditions. Say, something like the ISS Node with a pair of logistics modules, a large lander, and a habitat. With a cluster of ion engines, the first one could spend, say, three months spiraling out to lunar orbit and once it gets there drop the lander onto the surface along with all the supplies they need to setup the expedition. When the first ship gets on station, the second ship in the series launches and spends three months spiraling out to the moon to replace it; second ship arrives to relieve the first, which can then take a three-month flight back to Earth; it passes cruiser #3 on the way up, which in turn relieves #2, and so on.

With those four craft, you can do a rotating schedule to the lunar outpost and back, and if you pack smartly you aren't just maintaining the outpost, but slowly growing it with every new shipment of personnel and equipment. The best thing is, the kinds of modules used in this plan are small enough to be launched on a Falcon-9 or an Ariane 5. That would make the infrastructure relatively cheap to deploy, since an entire cruiser could be assembled in orbit using just six F9 launches, each deploying modules of a configuration that is already trivially easy to modify (that's five for the hardware and one for propellant, although a Falcon Heavy might be needed for the last one).

Anticipating publiusr's inevitable objection: no, launching the whole thing on an SLS is NOT a better idea, given the probably timeframe we're talking about would be 2020s to 2030s, by which time the Falcon 9 would be cheap enough and common enough to sustain a flight rate of about once every five weeks. You could have all four cruisers in orbit and operational within six months, with two more under construction during the initial rotation. More importantly, for safety and risk management missions, the landers, the cargo and the crews are probably going to get sent up on different flights anyway, very likely from totally different countries, and forcing them all to send their equipment and money to Cape Cannaveral just to wait in line for ten months for the next SLS would be a real business killer.

One simple lunar fuel I don't think anyone has looked at is molten aluminum/LOX. If the tank and piping are pressure-fed titanium or stainless steel with heater elements and ceramic aerogel insulation, it wouldn't be a very big deal to make such a craft for lunar ascent, though it might need to run very oxygen rich to keep chamber temperatures manageable.

I kind of like that idea... but how would you keep the aluminum molten?

 

[sojourner]

The problem with your idea is that means a lot of time spent in the Van Allen belts. Not a good thing for a healthy crew. You want to traverse them as quickly as possible.