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I'm curious whether anyone knows enough about EELVs to discuss them here. The Delta IV heavy and the new Atlas V are both pretty large; I think they can orbit 25 and 20 tonnes to low earth orbit, respectively (or maybe it is the other way around). The Ariane V will soon be in that range as well. I am wondering whether anyone knows how likely it is that these booster families can be expanded in the future, say, to the 30-tonne range, or even eventually to the 50-tonne range?
The commercial need for larger boosters may not exist, though a 30 tonne to LEO booster could launch three satellites to geosynchronous orbit instead of two (which is now done often). The obvious need, for our purposes, is for flights to Mars or the moon, which will require a total mass in low earth orbit of 100-200 tonnes or so (depending on your assumptions).
-- RobS
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The "Heavy" versions of both Delta IV and Atlas V can launch around 25 tons. The problem is that Lockheed Martin has no firm plans for Atlas V heavy (three common booster cores in parallel.)
I don't think an economic case can be made anytime soon for a heavy lifter, but the cost of NASA purchasing a few HLLVs can be minimized if such an HLLV can be built by clustering components from smaller boosters that are already in production. My hope is that Boeing and Lockheed Martin will design larger clusters of Delta IV and Atlas V to use for future Mars missions.
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Please excuse my ignorance in these things but I noticed Ad Astra mentioned an Atlas V with "three common booster cores in parallel".
If three booster cores can be used in parallel, in my mind's eye I can imagine four more being attached - for a total of seven booster cores all together!
First of all, is such a thing possible or practicable? And, secondly, if it were to be built, what kind of mass could it place in LEO?
???
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The concept of clustered rockets is not new. The Saturn I was formed of 8 Redstone tanks around a Jupiter tank core, but it had 8 Jupiter engines. Modern rockets use a different form of clustering; the Delta 7925 consists of 9 GEM40 boosters around a Delta Thor XLT-C stage, then other stages stacked on top. The Delta IV Large consists of 3 Delta RS-68 stages clustered together, then Delta 4H-2 upper stage stacked on the center. Atlas V is supposed to consist of an Atlas CCB (Common Core Booster) surrounded by 5 Atlas V SRBs and a Centaur V1 upper staged stacked on top. According to Astronautix.com that one can lift 20.050 tonnes to 185km at 28.5?. International Launch Services web site states it can lift 20.520 tonnes to LEO at 28.5?. There is a picture of an Atlas with 3 CCBs but Astronautix.com does not have any specifications for it, and the ILS web site doesn't show it at all.
Estimations of an extremely large launch vehicle can be interesting. Increasing the number of core stages from 3 to 7 does increase thrust by 7/3, but you also increase aerodynamic drag. For example, the Delta IV+(4,2) has one Delta RS-68 core stage, 2 GEM 60 solid rocket boosters, and a Delta 4-2 upper stage, and a 4 metre diameter payload fairing; it can lift 11.7 tonnes to 185km. The Delta IV+(5,2) has the same stage configuration, but a 5 meter payload fairing; it can only lift 10.3 tonnes to 185km. Then you have to worry about distributing payload weight, ensuring the weight applied to a single stage is not enough to crush it, and include rocket acceleration and aerodynamic drag force to that weight.
Let's take a wild guess. The Delta IV Medium consists of a single Delta RS-68 core stage and a Delta 4-2 upper stage. It can lift 8.6 tonnes to LEO. The Delta IV Large consists of 3 Delta RS-68 core stages and a Delta 4H-2 upper stage. It can lift 25.8 tonnes to LEO, which is exactly 3 times as much, but the upper stage (Delta 4H-2) is slightly larger as well. Following that simple progression then a Delta IV Oh-My-God Heavy would consist of 7 Delta RS-68 core stages with some speculative upper stage (perhaps a stack) which would lift 60.2 tonnes to 185km orbit at 28.5?. Interpolating to an ISS orbit, that would be about 35.7 tonnes. However, that would require a new launch facility.
Similarly the Atlas V 501 can lift 10.3 tonnes to 185km, so you would think a 3-core variant could lift 30.9 tonnes but that would require an enlarged Centaur upper stage. With the existing Centaur upper stage, Atlas V Heavy could probably lift more than Delta IV Large, but it would require a new mobile launcher.
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I am surprised no-one has mentioned the Energia SL-16 with payload capability of between 65,000kg and 200,000kg to low earth orbit.
http://home.attbi.com/~rusaerog/boosters/Energia.html
Cost is obviously a negative point, but with further R&D those can certainly be reduced.
Archie
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The issue of Enrgia has been the focus point of many heated threads on this forum.
Essentially, the Energia argument breaks down to this: Energia was the greatest booster mankind built, short of the Saturn V (and better in some aspects, because it was a highly modular system.) It would be difficult and possibly costly to restart production because much of the tooling is gone and the infrastructure degraded. In the end, it all boilds down to whether a newer booster can be built to the same (or higher) specs as Energia for a similar cost as reconstituting the Energia system.
My suspicion is that it would be cheaper to build a HLLV from Delta IV or Atlas V components, because the booster cores and engines are in production, and the facilities to launch them are operating. A shuttle-derived vehicle, akin to Shuttle C or Zubrin's Ares, would be feasible, but it would be hindered by additional expenses like modifications to the hardware and launch infrastructure.
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The Russians also have an EELV in the works. Called "Angara," it's an attempt by Russia to move away from using launch facilities in Kazakhstan and factories in the Ukraine. Powered by one RD-191 engine per common booster core, it is available in clusters of one, three, and five. The Angara 5 Heavy can put 11.2 tonnes in GTO, just short of the Delta IV heavy. The most exciting development on the Angara front is a proposed flyback booster core with a scissor wing, sometimes referred to as "Baikal."
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Where would it launch from?
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Angara will likely launch from Plesetsk. I'm most excited about the winged, recoverable variant of Angara, granted the Russians find the money to build and test it.
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I was reading about Buzz Aldrin's idea for a TSTO reusable booster/spaceplane-a booster cased in an airplane (Boeing 747, I believe-I know it was a 7x7), with the payload on top. The plane would then fly back down.
It sounded pretty good-but I don't know how an airplane would fare with liquid fuel and a booster inside.
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The idea of ejecting an RLV from a cargo aircraft or launching from on top a large subsonic aircraft is not new. I just haven't heard Buzz Aldrin promoting it. To date, Buzz has been talking about vertical takeoff vehicles with reusable "Starbooster" flyback boosters.
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