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Ares alternatives? "NASA renegades"
How real is this?
http://www.popularmechanics.com/scie...buzz&mag=po p -- Kulvinder Singh Matharu Website : www.metalvortex.com Contact : www.metalvortex.com/contact/ Brain! Brain! What is brain?! |
#2
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Ares alternatives? "NASA renegades"
"Kulvinder Singh Matharu" wrote in message ... How real is this? http://www.popularmechanics.com/scie...buzz&mag=po p http://www.directlauncher.com/ How "real" it is, is a matter of opinion. In my opinion, it's a better option that Ares but a worse option to using EELV's (and any emerging launch providers in the future) in combination with developing in orbit refueling depots. Jeff -- "Many things that were acceptable in 1958 are no longer acceptable today. My own standards have changed too." -- Freeman Dyson |
#3
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Ares alternatives? "NASA renegades"
"Jeff Findley" writes:
"Kulvinder Singh Matharu" wrote in message ... How real is this? http://www.popularmechanics.com/scie...buzz&mag=po p http://www.directlauncher.com/ How "real" it is, is a matter of opinion. In my opinion, it's a better option that Ares but a worse option to using EELV's (and any emerging launch providers in the future) in combination with developing in orbit refueling depots. I'm still not getting how you want to get lunar or Mars landers on their way with EELV's. Sewing 10-15 ton modules together into a Mars lander seems not exactly easy, especially if alone the heatshield won't fit under the payload shroud in one piece. Fuel is important, but it's not everything. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery |
#4
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Ares alternatives? "NASA renegades"
"Jochem Huhmann" wrote in message ... "Jeff Findley" writes: "Kulvinder Singh Matharu" wrote in message ... How real is this? http://www.popularmechanics.com/scie...buzz&mag=po p http://www.directlauncher.com/ How "real" it is, is a matter of opinion. In my opinion, it's a better option that Ares but a worse option to using EELV's (and any emerging launch providers in the future) in combination with developing in orbit refueling depots. I'm still not getting how you want to get lunar or Mars landers on their way with EELV's. Sewing 10-15 ton modules together into a Mars lander seems not exactly easy, especially if alone the heatshield won't fit under the payload shroud in one piece. Fuel is important, but it's not everything. There is no law of physics that says heat shields need to be one piece. The shuttle, for example, has a few openings in the base of its heat shield for the landing gear, LOX and LH2 lines to the ET, and etc. Also, a Gemini capsule was re-flown as part of the MOL program and it had a hatch in it. It worked just fine too. Even with Ares V, a Mars mission is going to need to be assembled in LEO from many launches. The bulk of that mass is fuel and oxidizer for the engines, so a LEO fuel depot makes a lot of sense to develop. Jeff -- "Many things that were acceptable in 1958 are no longer acceptable today. My own standards have changed too." -- Freeman Dyson |
#5
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Ares alternatives? "NASA renegades"
Jochem Huhmann wrote:
I'm still not getting how you want to get lunar or Mars landers on their way with EELV's. Sewing 10-15 ton modules together into a Mars lander seems not exactly easy, especially if alone the heatshield won't fit under the payload shroud in one piece. Fuel is important, but it's not everything. Does anyone really think that one could mount a mars expedition without assembling a huge "space station" for the expedition ship ? When you consider the biggest thing we've sent to mars so far, do you really think that you could magically send a cargo ship capable of landing on mars in one launch ? Do you think we could send a fully outfitted habitat to the surface of mars ahead of time with a single launch ? Having a good launcher will help reduce the number of launches needed to assemble a mars expedition. (whether set as one ship or as 2 ships, you still need to send that mass to LEO and assemble it in one or two chunks before sending it. |
#6
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Ares alternatives? "NASA renegades"
"Jeff Findley" writes:
I'm still not getting how you want to get lunar or Mars landers on their way with EELV's. Sewing 10-15 ton modules together into a Mars lander seems not exactly easy, especially if alone the heatshield won't fit under the payload shroud in one piece. Fuel is important, but it's not everything. There is no law of physics that says heat shields need to be one piece. The shuttle, for example, has a few openings in the base of its heat shield for the landing gear, LOX and LH2 lines to the ET, and etc. Also, a Gemini capsule was re-flown as part of the MOL program and it had a hatch in it. It worked just fine too. There's no law of physics that say heat shields need to be one piece, right. But assembling such a lander (structure, heatshield and all) from rather tiny chunks is a nightmare. You can't just easily dock together things for that. You'll need a crew and do rather delicate work for that and then you'll need to have even more launches. Look at how many launches and EVA hours the ISS has needed and then show me how you assemble a Mars craft this way. And then even without the Shuttle (which at least has the crew already with it) and without the crew on the station... no way. How many launches of EELV's for pieces and assembly crews you're thinking of here? 100? 200? Even with Ares V, a Mars mission is going to need to be assembled in LEO from many launches. The bulk of that mass is fuel and oxidizer for the engines, so a LEO fuel depot makes a lot of sense to develop. I have nothing against fuel depots and in-orbit assembly. But I think that current EELV's are just too small to deliver useful pieces of such crafts, both mass- and size-wise. 60 to 100 tons of payload and 8 to 10 meters payload diameter makes all of this at least an order of magnitude easier and this is easily worth a new launcher. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery |
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Ares alternatives? "NASA renegades"
John Doe writes:
Having a good launcher will help reduce the number of launches needed to assemble a mars expedition. (whether set as one ship or as 2 ships, you still need to send that mass to LEO and assemble it in one or two chunks before sending it. But if you want to launch that on current EELV's you will deliver at most 10 to 15 tons of equipment with one launch (since every single payload will need power and engines and fuel and more). Add to this the needed crews to assemble non-trivial stuff which you also have to launch and you end up with dozens or more launches, not two or three. This is just not practical. You'll have to launch modules that are assembled and tested on the ground and which don't need any manual work to join them. You most certainly don't want to assemble a heat-shield for a Mars lander from a dozen different pieces launched seperately. You probably even don't want to assemble the structure and tanks and engines and pressure vessel and airlock and other equipment for a moon lander this way. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery |
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Ares alternatives? "NASA renegades"
Jochem Huhmann wrote:
But if you want to launch that on current EELV's you will deliver at most 10 to 15 tons of equipment with one launch (since every single payload will need power and engines and fuel and more). Honest question he Is it realistic to expect launchers that could scale much beyond the 15 tonnes that we have now ? Someone mentioned 100 tonnes. Is that realistic with either H2O2 or Kerosene propulsion systems ? At oe point, wouldn't these become just too big/high and generate way too much noise/vibration etc ? |
#9
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Ares alternatives? "NASA renegades"
John Doe writes:
Honest question he Is it realistic to expect launchers that could scale much beyond the 15 tonnes that we have now ? Someone mentioned 100 tonnes. Is that realistic with either H2O2 or Kerosene propulsion systems ? At oe point, wouldn't these become just too big/high and generate way too much noise/vibration etc ? The Saturn V had a payload to LEO of 118 tonnes. Ares V is planned to have a payload to LEO of 188 tonnes. Jochem -- "A designer knows he has arrived at perfection not when there is no longer anything to add, but when there is no longer anything to take away." - Antoine de Saint-Exupery |
#10
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Ares alternatives? "NASA renegades"
Jochem Huhmann wrote:
The Saturn V had a payload to LEO of 118 tonnes. Ares V is planned to have a payload to LEO of 188 tonnes. Ok then. I thought that the Shuttle had some the strongest engines (but I guess the vehicle itself ate all that power leaving a 15tonne payload). Ok, so if 120 tonnes is possible and has been done, then I guess it is quite a realistic payload to expect. |
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