RSS iconTwitter iconFacebook icon

The Trek BBS title image

The Trek BBS statistics

Threads: 140,952
Posts: 5,479,877
Members: 25,057
Currently online: 598
Newest member: Ghost_of_Bubba

TrekToday headlines

USS Enterprise Press-Out And Build Manual
By: T'Bonz on Nov 28

New QMx USS Reliant Model
By: T'Bonz on Nov 28

Star Trek Thirty-Five Years On 35MM: A Retrospective
By: T'Bonz on Nov 28

Trek Shirt And Hoodie
By: T'Bonz on Nov 27

A Klingon Christmas Carol’s Last Season
By: T'Bonz on Nov 27

Attack Wing Wave 10 Expansion Pack
By: T'Bonz on Nov 27

New Star Trek Funko Pop! Vinyl Figures
By: T'Bonz on Nov 26

QMx Mini Phaser Ornament
By: T'Bonz on Nov 26

Stewart as Neo-Nazi Skinhead
By: T'Bonz on Nov 26

Klingon Bloodwine To Debut
By: T'Bonz on Nov 25


Welcome! The Trek BBS is the number one place to chat about Star Trek with like-minded fans. Please login to see our full range of forums as well as the ability to send and receive private messages, track your favourite topics and of course join in the discussions.

If you are a new visitor, join us for free. If you are an existing member please login below. Note: for members who joined under our old messageboard system, please login with your display name not your login name.


Go Back   The Trek BBS > Entertainment & Interests > Science and Technology

Science and Technology "Somewhere, something incredible is waiting to be known." - Carl Sagan.

Reply
 
Thread Tools
Old October 13 2012, 05:37 PM   #226
publiusr
Commodore
 
Re: Envisioning the world of 2100

newtype_alpha wrote: View Post
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/spacedat...star_sum.shtml
http://www.nasaspaceflight.com/2006/...ally-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.


newtype_alpha wrote: View Post
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


newtype_alpha wrote: View Post
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.

newtype_alpha wrote: View Post
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


newtype_alpha wrote: View Post
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.



newtype_alpha wrote: View Post
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.

newtype_alpha wrote: View Post
"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.


newtype_alpha wrote: View Post
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?


newtype_alpha wrote: View Post
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.

Last edited by publiusr; October 13 2012 at 05:58 PM.
publiusr is offline   Reply With Quote
Old October 13 2012, 06:05 PM   #227
sojourner
Admiral
 
sojourner's Avatar
 
Location: I'm at WKRP
Re: Envisioning the world of 2100

I give up. He's just too determined to have a Big Shiny Rocket as opposed to getting things done.
__________________
Baby, you and me were never meant to be, just maybe think of me once in a while...
sojourner is offline   Reply With Quote
Old October 13 2012, 06:11 PM   #228
publiusr
Commodore
 
Re: Envisioning the world of 2100

Saturn V got things done. Venture Star was the waste of money. That was the shiny distraction.
publiusr is offline   Reply With Quote
Old October 13 2012, 07:35 PM   #229
sojourner
Admiral
 
sojourner's Avatar
 
Location: I'm at WKRP
Re: Envisioning the world of 2100

Saturn V is a museum piece. SLS is your BSR.
__________________
Baby, you and me were never meant to be, just maybe think of me once in a while...
sojourner is offline   Reply With Quote
Old October 13 2012, 08:08 PM   #230
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

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!
gturner is offline   Reply With Quote
Old October 13 2012, 09:30 PM   #231
publiusr
Commodore
 
Re: Envisioning the world of 2100

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.
publiusr is offline   Reply With Quote
Old October 13 2012, 10:26 PM   #232
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

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.
gturner is offline   Reply With Quote
Old October 14 2012, 04:16 AM   #233
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: Envisioning the world of 2100

publiusr wrote: View Post
newtype_alpha wrote: View Post
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.

newtype_alpha wrote: View Post
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.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old October 14 2012, 11:50 PM   #234
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

newtype_alpha wrote: View Post
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_Art...plications.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.
gturner is offline   Reply With Quote
Old October 15 2012, 01:45 AM   #235
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: Envisioning the world of 2100

^ 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.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old October 15 2012, 03:58 AM   #236
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

newtype_alpha wrote: View Post
^ 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.
gturner is offline   Reply With Quote
Old October 15 2012, 06:46 PM   #237
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: Envisioning the world of 2100

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).
__________________
The Complete Illustrated Guide to Starfleet - Online Now!

Last edited by Crazy Eddie; October 15 2012 at 07:07 PM.
Crazy Eddie is offline   Reply With Quote
Old October 15 2012, 07:40 PM   #238
gturner
Admiral
 
Location: Kentucky
Re: Envisioning the world of 2100

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.
gturner is offline   Reply With Quote
Old October 16 2012, 06:37 AM   #239
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: Envisioning the world of 2100

gturner wrote: View Post
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?
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old October 16 2012, 07:05 AM   #240
sojourner
Admiral
 
sojourner's Avatar
 
Location: I'm at WKRP
Re: Envisioning the world of 2100

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.
__________________
Baby, you and me were never meant to be, just maybe think of me once in a while...
sojourner is offline   Reply With Quote
Reply

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT +1. The time now is 03:52 AM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
FireFox 2+ or Internet Explorer 7+ highly recommended.