#11
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The 100/10/1 Rule.
kT wrote:
Sylvia Else wrote: It's all about the overall cost of putting payload into orbit. A TSTO would presumably give a better payload ratio, but with extra complexity (equals dollars) both in the vehicles themselves, and in handling the vehicles when they're in use. So the net cost per kg in orbit may be higher for a TSTO than for an SSTO despite the higher payload ratio. An airliner style operation using a single vehicle per mission is very attractive if it's achievable. After the vehicle lands, you just refuel it, put in the next mission's payload and you're ready to launch again. And I posit we must approach that SSTO RLV launch scenario incrementally. The 100/10/1 puts the masses involved in perspective. However, one can argue that the expendable SSTO approach puts almost an order of magnitude more mass into orbit, which is what I am suggesting. Only because you're deeming that the spacecraft hardware in orbit is part of the payload. That's fine if you have someone who wants that payload in orbit, but most launches involve other kinds of payload. Sylvia. |
#12
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The 100/10/1 Rule.
Sylvia Else wrote:
kT wrote: Sylvia Else wrote: It's all about the overall cost of putting payload into orbit. A TSTO would presumably give a better payload ratio, but with extra complexity (equals dollars) both in the vehicles themselves, and in handling the vehicles when they're in use. So the net cost per kg in orbit may be higher for a TSTO than for an SSTO despite the higher payload ratio. An airliner style operation using a single vehicle per mission is very attractive if it's achievable. After the vehicle lands, you just refuel it, put in the next mission's payload and you're ready to launch again. And I posit we must approach that SSTO RLV launch scenario incrementally. The 100/10/1 puts the masses involved in perspective. However, one can argue that the expendable SSTO approach puts almost an order of magnitude more mass into orbit, which is what I am suggesting. Only because you're deeming that the spacecraft hardware in orbit is part of the payload. That's fine if you have someone who wants that payload in orbit, but most launches involve other kinds of payload. Then they can launch on little Dneprs for all I care, I want to colonize space, and the 100/10/1 rule is the only way I know how. If I'm going to be flying around in a large spaceship for any length of time, I want as much fuel and hardware as I can get. By leveraging the 10/1 rule to our advantage the material and infrastructure in orbit gets large very fast. Plus, I can get the engines back, so it's sustainable, and it's an order of magnitude less flights that it otherwise would have taken. Thus, it's scalable and sustainable so things only get bigger and better over time. -- Get A Free Orbiter Space Flight Simulator : http://orbit.medphys.ucl.ac.uk/orbit.html |
#13
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The 100/10/1 Rule.
Alan Jones wrote:
On 4 Mar 2007 08:29:52 -0800, "Frogwatch" wrote: On Mar 4, 11:28 am, "Frogwatch" wrote: On Mar 2, 4:42 pm, kT wrote: I've been simulating single stage to orbit (SSTO) launch to low earth orbit (LEO) in orbiter space flight simulator for a little while now. In order to increase this payload, the obvious solution is converting the rocket itself into payload. BTW, why ssto, wouldnt tsto give better payload ratio? Certainly, but kT is playing some sort of game with SSTO. It's not a game, it's a fully qualified space simulator. SSTO itself is just an engineering challenge, not the most economical way to achieve orbit. Most SSTO studies postulate a fully reusable vehicle to achieve some level of economy, but the margins, payload performance, and real costs just are not competitive. kT's cannibalistic SSTO vehicle seems pointless. I'm not cannibalizing anything, I'm designing it all in from scratch. Everything is used as is. At the most, it will require a space suit to get into the hydrogen tank to seal the ports. All the the pressurization hardware can be used as is. If anything, I'll be adding hardware to it. -- Get A Free Orbiter Space Flight Simulator : http://orbit.medphys.ucl.ac.uk/orbit.html |
#14
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The 100/10/1 Rule.
On Sun, 04 Mar 2007 20:46:23 -0600, kT wrote:
However, one can argue that the expendable SSTO approach puts almost an order of magnitude more mass into orbit, which is what I am suggesting. Has anyone ever put anything into orbit with a single stage? I know we've managed SSTS, Single Stage To Space, but I don't think we've managed SSTO. Mary "Haven't thought about this for years" -- Mary Shafer Retired aerospace research engineer We didn't just do weird stuff at Dryden, we wrote reports about it. or Visit my new blog at http://thedigitalknitter.blogspot.com/ |
#15
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The 100/10/1 Rule.
On Mon, 05 Mar 2007 14:10:19 -0800, in a place far, far away, "Reunite
Gondwanaland (Mary Shafer)" made the phosphor on my monitor glow in such a way as to indicate that: On Sun, 04 Mar 2007 20:46:23 -0600, kT wrote: However, one can argue that the expendable SSTO approach puts almost an order of magnitude more mass into orbit, which is what I am suggesting. Has anyone ever put anything into orbit with a single stage? I know we've managed SSTS, Single Stage To Space, but I don't think we've managed SSTO. The old Atlas could have come pretty close. With a small enough payload, it might have been able to. |
#16
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The 100/10/1 Rule.
Rand Simberg wrote: The old Atlas could have come pretty close. With a small enough payload, it might have been able to. That would be fun to figure out; the weight of the aft skirt and its engines versus that of the LEO payload. The Atlas H 1/2 stage weighed 8,038 lb according to Encyclopedia Astronautica; payload to LEO is 8,000 pounds, so with a lightweight aerodynamic nosecone, who knows? You'd be able to strip some weight off of the 1/2 stage because it wouldn't have to separate, so the plumbing could be simpler. It'd be a mighty low orbit, but you might be able to do it. Pat |
#17
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The 100/10/1 Rule.
"Pat Flannery" wrote in message
... Rand Simberg wrote: The old Atlas could have come pretty close. With a small enough payload, it might have been able to. That would be fun to figure out; the weight of the aft skirt and its engines versus that of the LEO payload. The Atlas H 1/2 stage weighed 8,038 lb according to Encyclopedia Astronautica; payload to LEO is 8,000 pounds, so with a lightweight aerodynamic nosecone, who knows? Hmm, and can you upgrade the engines at all? Might gain you a bit more. So.. what could you do with say: 200lbs 500lbs 1000lbs I think the first 2 are basically "small sat" type things. 1000lbs, a bare minimum once around capsule? You'd be able to strip some weight off of the 1/2 stage because it wouldn't have to separate, so the plumbing could be simpler. It'd be a mighty low orbit, but you might be able to do it. Pat -- Greg Moore SQL Server DBA Consulting sql (at) greenms.com http://www.greenms.com |
#18
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The 100/10/1 Rule.
Greg D. Moore (Strider) wrote: Hmm, and can you upgrade the engines at all? Might gain you a bit more. So.. what could you do with say: 200lbs 500lbs 1000lbs I think the first 2 are basically "small sat" type things. 1000lbs, a bare minimum once around capsule? It really doesn't make any sense though. Because of its size and low mass, the Atlas booster will destructively reenter in fairly short order from air drag anyway, so you really haven't gained anything by doing it this way. It would make more sense to figure out how to recover the 1/2 stage after jettison. But the two engines in that were fairly cheap low-tech ones, so that really doesn't make any sense either, considering the amount of payload you'd lose from the weight of the recovery system. Pat |
#19
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The 100/10/1 Rule.
Reunite Gondwanaland (Mary Shafer) wrote: Has anyone ever put anything into orbit with a single stage? I know we've managed SSTS, Single Stage To Space, but I don't think we've managed SSTO. Mary "Haven't thought about this for years" Scott Lowther claimed a long time back that Thor could do it, but then backed off that statement. I wonder if Thor could, minus any payload? I think the single stage Atlas conversion would be the most reasonable choice. It's almost going to have to be something using balloon tankage to get the mass fraction to where it's good enough to do the job. Pat |
#20
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The 100/10/1 Rule.
"Reunite Gondwanaland (Mary Shafer)" writes:
On Sun, 04 Mar 2007 20:46:23 -0600, kT wrote: However, one can argue that the expendable SSTO approach puts almost an order of magnitude more mass into orbit, which is what I am suggesting. Has anyone ever put anything into orbit with a single stage? I know we've managed SSTS, Single Stage To Space, but I don't think we've managed SSTO. I assume there's an implied "earth" before orbit there, since all the lunar landing LMs' ascent stages were SSTO, albeit lunar. |
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