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#76 Re: Human missions » NASA 2006 Budget » 2005-11-02 18:33:46
I personally think we should pull every penny in aid we are giving to Africa and put it towards VSE.
#77 Re: Human missions » More Chinese space tech stuff » 2005-10-18 22:19:16
One more reason to point a few more warheads at the prc 
#78 Re: Human missions » NASA's Moon Mission » 2005-09-28 20:03:09
125MT is low? No its not, the four-SSME version would only lift 110MT.
Don't get hung up on Bob Zubrin's 120MT figure for Ares, which was equipped with the ASRM version of the SRB, which was never built and is not an option.
NASA did look at a quad-SRB version actually, which would lift around 135-140MT probobly. Given the weight of the SRBs (they're kinda heavy), you get diminishing returns.
As far as the RS-68, the 68's thrust is already quite good, but its specific impulse leaves something to be desired. Adding a regenerative cooling loop would improve the situation, but because the 68' is a low-pressure engine its impossible to reach SSME-like specific impulse. The SSME is unique with its very high operating pressure, which gives it a performance thats hard to match. Modifying the 68' for higher chaimber pressure would be very difficult I bet, it would essentially be a new engine.
However, it is worthwhile to question if the 68's higher thrust makes up for its lower performance: NASA also considerd an alternative to the SSME-powerd "Magnum," a five-68' powerd core called "Longfellow." It would, in theory, have about the same or slightly less payload.
However, the RS-68 has one drawback that may not be apparent, that it isn't designed to be restartable. If NASA ever wanted to launch Magnum without an upper stage or a seperate, new kick stage, then it might re-ignite the central SSME for orbital circulization. That would yeild a launcher with about the right payload for NASA DRM-III style Mars missions.
The SSME will be powering The Stick anyway, so perhaps a cheaper version can be developed, and its definatly questionable if we should develop both a cheaper SSME and a higher-performance RS-68.
I definetly agree that developing both a simplified SSME or an uprated RS-68r would not be wise, it's a one or the other situation, I just question how straight forward it will be to make a cheapened high production rate SSME.
I also worry about sub 150 tonnes to LEO being enough to support a permanent presence on the moon or Mars, but I don't really see any near term options for a 150-200 tonnes class launcher without going clean sheet or doing something really radical to the shuttle stack.
#79 Re: Human missions » NASA's Moon Mission » 2005-09-28 19:13:06
Does anyone know what the payload capacity of the HLLV. Is that the final configuration? I heard 125 tonnes to LEO and thought that sounded low with 5 SSMEs and 5 segement SRBs.
How would 4 five segement SRBs affect it's lifting capacity? Wouldn't using the RS-68 with a regerative nozel provide more thurst and a lower cost engine?
#80 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-19 21:29:19
One vehicle that does meat the requirement of reentry landing on a runway and a quick turnaround time is the x-37. However, the X-37 only has a 4% payload fraction and we do not have enough information from the program to know if it caries enough fuel for a useful second stage or why the payload fraction is so bad. In all likelihood the X-37 falls far short of a useful reusable second stage vehicle. However, I believe the basic design is good and with a larger vehicle, lighter materials, and less stuff inside it that would be useful to the military but might not be needed by NASA the X-37 could form a good starting point for a second stage vehicle.
X-37 is really a payload, like the manned capsules before it. It doesn't have much propellant, other than for maneuvering once on-orbit. X-37's orbital capabilities are moot right now because there isn't any money to fund it after the White Knight drop tests end.
Would the X-37 shape make for a good booster? I wouldn't think so, because the shape has a low fineness ratio and would rpduce a lot of drag. Many re-entry vehicles are designed to be draggy so they bleed off energy in the atmosphere.
I've often looked at the X-34 as a good shape for a booster. But we have to remember that the X-34's wings were designed for the pitching maneuver that would have followed separation from the mothership. So the X-34's wings were probably oversized for a booster that is only going to be generating lift after its propellants are used up.
A good shape for the flyback booster was the Rockwell X-33 concept. Looking like a bloated X-34, it was a winged rocket that would have glided to a landing after a suborbital ~Mach 15 flight.
I don't know much about the Rockwell X-33 concept, but I got the distinct impression that it was essentially the Shuttle fattened up enough to contain the external tanks volume, I could be wrong and it could be more advanced then that bit </shrug> Like I said I don't really know.
As far as a TSTO based around a hypersonic first stage carrier, well just watch the AF, that might be coming sooner then you think.
#81 Re: Human missions » NASA's Moon Mission » 2005-09-19 12:48:26
Whatever happened to using Lunox? What about a heavy cargo lander?
Other then the inline SDV HLLV I don't see anything about how this is going to get us to Mars. That worries me.
#82 Re: Interplanetary transportation » Falcon 1 & Falcon 9 » 2005-09-10 14:04:51
FALCON = Force Application Launched from the CONtinental US.
lol, I know, it's definetly a stretch as far as acronyms go.
#83 Re: Human missions » Neil Armstrong: Mars easier than Moon » 2005-09-07 00:41:39
^Not to mention punching out members of the tin foil hat crowd.
My all time favorite internet movie clip, that was great.
On the subject of encounter with Tiber, it really illistrates how we should have reacted to columbia, although I do have some serious questions about how robust a modified ET would be as a habititat....maybe if you the put kevlar and nextel foam blanket around it once in orbit for additional sheild and micro meteor protection.
#84 Re: Human missions » Neil Armstrong: Mars easier than Moon » 2005-09-06 17:03:15
Just want to point out he's a Purdue alum, lol, the Neil Armstrong Center for Aerospace Engineering is supposed to open next year here...I wonder if he'll be here for the opening.
I do however have to disagree with the more the 20 years comment, it may end up being 20 years, but from a technological readiness standpoint, we could do it in less then 10 if given the cash, inline HLLV SDV, nuclear reactor for power and ISRU, mix in a NTR if your feally really industrious...voila, not only h2m, but everything you need for an expanding permanent program.
#85 Re: Interplanetary transportation » Falcon 1 & Falcon 9 » 2005-09-04 15:41:39
I must say some of you USAF guys haven't been good friends of space. Jumper did a lot of damage and the way Pete Worden was treated was criminal.
I see the Air Farce is still run by the pilots unions and the fighter mafia.
Yes, much to my great frustration the Air Force is still very much run by the fighter mafia, but their strangle hold is finally starting to be broken, and for the first time it's looking good that jumpers replacement might be a non-pilot.
Also, the missiles and space feild is very much hamstrung by the fact that what would be prestige postings deal entirely with top secret or SAR systems, so if you can't tell anyone what your doing, or how uber the R and D or procurment program you ran was, then it seriously hurts your chance of joining the ranks of the guys with the stars on their shoulders.
#86 Re: Interplanetary transportation » Falcon 1 & Falcon 9 » 2005-09-01 08:57:10
It could very well be that the giants that Space-X might bring down could have a hand in the issue, but the rules reguarding launching one vehicle while a fully stacked vehicle is on another pad at Vandenburg have been around for a long, long time, back when rockets had even odds of blowing up during their ascent they didn't want debris, likley very toxic high explosive debris falling on their next multimillion dollar launcher and it's billion dollar payload.
It should be pointed out that for AltSpace there are options now other then Vandenburg and the Cape, there's the Atoll, the Illeution Islands space port, and now the New Mexico space port, any of which could turn into the altspace equivilent of KSC.
#87 Re: Interplanetary transportation » What's the Biggest Rocket Concievable? - How big can you really build it? » 2005-08-13 18:13:40
The largest chemical launcher I think would have been viable was the Sea Dragon.
http://astronautix.com/lvs/searagon.htm
Alot of work was actually done on production viability and it was found that it would be realativley easy to produce in an existing ship yard at a individual unit cost much lower then the Saturn V due to cheaper componets and simpler construction more then off setting it's larger size. It was capable of launching 550 tonnes to LEO. [/url]
#88 Re: Human missions » International Space Agency (ISA) » 2005-08-13 17:56:47
</slaps palm against head>
Not this again...
besides international is not the friend of space programs, in fact its the anti-friend, prehaps even the enemy. </cough>ISS
#89 Re: Interplanetary transportation » Project Orion » 2005-08-06 16:53:06
I think the only way you could ever make an orion system work is to use pure fusion type devices. These would lend themselves beter to the low yeilds desired by an orion and would also side step the fallout issue. Also they would be significantly cheaper, 6lithium deuteride is reletivley cheap to produce compared to highly enriched uranium or plutonium.
The problem with small fission bombs is that bellow a certain yeild you start to get significantly diminishing returns in terms of kiloton yeild per gram of fuel. The Davy Crocket was the smallest warhead produced by the United States weighed 51 pounds and used an oblique implossion configuration, which while still more efficent then gun type fission device, but no where near as efficent as the Greenhouse King configuration, which was the single most efficent fission only wahead configuration.
Now that I'm thinking about it there might have been some ultra efficent smaller fission warheads during the ivy shots, and prehaps later in Nevada after the open air test ban, but my point remains the same.
#90 Re: Science, Technology, and Astronomy » Sono-Fusion » 2005-07-24 01:43:21
Sound generated by the energy released driving an electromagnetic coil...
LOL, and I lament the conversion efficencies of steam turbines from nuclear reactors!
If we could get He3/D2 fusison working then we can use magneto hydrodynamic coupling which has amazingly high, technically daunting conversion efficencies.
#91 Re: Not So Free Chat » Battlestar Galactica - SO what do you think about the new show? » 2005-07-24 01:37:03
The clash between military and non-military views helps keep the show interesting.
Unfortunately Adama isn't being written as a particularly adept military commander, IMOSHO. Already we've seen him want to attack when he can't possibly win and risk the entire fleet for personal reasons. But then I suppose a more sensible approach wouldn't make for as much tension.
The Cylon ship, being a cyborg type fusion of organic and machine surprised me. I get the feeling the Cylons are going to come in all kinds of forms.
But can you grill 'em?
Cobra, that is one of things I love about the show. The Galactica and her crew weren't the best the fleet had to offer. Far from it, they were almost weekend warriors, getting ready to move on with their lives after the military with the great forces that had been built to defend from and beat back the cylons being dismantled, then them all of a suddent being thrust into the front line all of a sudden. They are just ordinary, unspectacular people in an extraordinary situation. Just think of the people who were on a nice cruise for vacation then all of a sudden the ship is now their permanent home.
LOL, to me the show seems reflective of the current world, the slashes in the military strength in the 90s, then bam, we're back in war and forced to put reserve and back up units on the front lines.
#92 Re: Human missions » MANNED MISSION TO TITAN BY 2040!!!! » 2005-07-23 23:02:14
Well I definitely doubt that there are 'many' scientist calling for this but…
idk, if in the next 20 years we have some sort of major break through in magnetically confined or pulse fusion, or the ability to create anti-matter in gram quantities relatively cheaply combined with some sort of hydrogen sulfide induced hibernation system, maybe humans to titan might happen by 2040, but I don't really see any of those things happening in the next 40 years, but then again in 40 years we went from the Wright brothers to the first fighter jets so you never know....
#93 Re: Science, Technology, and Astronomy » Sono-Fusion » 2005-07-18 21:30:42
Just have to plug the alma mater
http://www.spacedaily.com/news/energy-t … 5zzzu.html
It's very interesting research, and I think it has alot of promise as a low cost source or tritium, which is very badly needly to offset the tritium shortage we are now facing in the defense and research community, but I have a hard time seeing how such a device could be used to generate power.
#94 Re: Human missions » How much would the first step cost? - Cheapest first step, what can we afford? » 2005-07-17 01:28:08
As much as I hate to say it, the best way to spend $2mil to further the cause of H2M is likely in the form of advocacy.(sp?...it's late + vodka) Hire a marketing firm to produce some slick commercials, or make campaign contributions to members of the appropriations committee.
Two million might go along way to getting some real money for the cause.
#95 Re: Human missions » Shuttle Derived II - last thread crashed » 2005-07-06 18:23:31
Just an observation I'd like to throw into the fray, everyone is still citing the SSMEs as the main engine for a heavy lift SDV, doesn't using and RS-68R make more sense as they were cheaper and designed to be expendable?
Also for all the talk of NTRs (I am personally in highly in favor of their use, as well as any form of lunar IRU) does anyone know if NASA has actually put any money or requests for information out about a resurected NTR program. Thus far the only NASA nuclear programs I am aware of are for next gerneration RTGs and power reactors for space.
#96 Re: Human missions » The viability of the DC-Y » 2005-06-19 22:23:04
Hello all,
In a number of posts I have heard many people cite the DC-Y as the program that should have been the launch vehicle of the 90s'. Given the imense sucess of the DC-X I think it's fair to say that McDonnel Douglas should have gotten the X-33 contract based on that alone, but there's a topic for another post.
My point is I was just reading up on the DC-Y on astronautix and I am not horribly well informed on that project, but I'm inclined to wonder if it would have been able to make it as an SSTO given that it would have to carry fuel for landing, a significant mass penalty. The issue of tankage would be the same as on the failed LockMart X-33, but I am of the opinion that we gave up on that too quickly (the tanks not the X-33). The problem with laminating carbon fiber is just engineering, there are no fundamental systemic problems with the technology.
I guess specifically I was hoping that the newmars hivemind could point out.
A.) What effects that higher density liquid hydrogen, or hydrogen slush would have and
B.) Wether Aluminum-Lithum alloy tanks have weight advantages over carbon fiber and which of the two has a strength advantage.
#97 Re: Science, Technology, and Astronomy » NIF: $2.8 billion down the drain?? » 2005-06-18 18:51:31
I'm not too worried about the money situation yet, this is the sort of thing that gets hammered out in confrence between the Senate and House versions of the bill.
The NIF has some major implications for fusion research, and since it's the only fusion project currently active in the US I would hate to see it killed.
Also it's implications for space propulsion are huge.
#98 Re: Civilization and Culture » The Local Currency - How many Martian Spanners does it cost? » 2005-06-09 18:17:03
I think that buy the time Mars has a significant enough population to justify a curency independent from the USD either automated manufactories or nanotechnology will have advanced to the point that the material cost of most things will be basically deflated. Due to this the cost of any item will be based around A.) the intelectual property cost and B.) the time it takes in local manufactories or nano-fabs. As such I think an proper unit of curency for Mars might be the nanofab second/minute/hour.
#99 Re: Human missions » Shuttle derived revival - Space.com » 2005-06-08 00:20:02
I think that the term SDV is a pretty ill defined term at this point. It could mean anything from current stack + cargo pod to redesigned tank for inline with RS-68r engine pods, which is damn closed to a clean sheet vehicle, so I'm not up to panikcing yet.
If we went with an inline design with RS-68rs, would it be possible to use 4 SRBs arranged around the 'core' rather then the two. SRBs are a very cheap are reliable way to add thrust, and 4 SRBs would really increase the throw weight of the booster.
#100 Re: Human missions » Master of AI » 2005-05-23 17:22:33
Well I think you could put automate alot of simple resource utilization tasks up to a point.
For example, I think it would be very possible to land a completely automated construction materials factory. Engineer a couple of loader dump truck rovers and a central receiving center to crack it and produce cement and other by products and then feed them into a smelter to produce magnesium alloy and then cast it into rebar.
The crew can then land and bring along compressors and air bladders and then will have all the materials to produce a series of monolithic domes. I forgot what the construction technique was called but it involeves laying a foundation, and then setting an air bladder on top of it. then a web of rebar and concrete (and I would guess in the case of mars heating elements) is laid up on top of the bladder, which is then inflated producing a dome. You can then reuse the bladder and build another dome, and another and so on...
At least that's how I can envision producing habititats on Mars using completely endigenous(sp?) materials.