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Request Atlas V Heavy-Lift Evolution

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http://www.ulalaunch.com/site/docs/product_cards/guides/AtlasVUsersGuide2010.pdf , page 351

8.2.3 Heavy-Lift Evolution
Development of the 5-m diameter evolved upper stage and 5-m diameter booster lay the foundation for further Atlas evolution to support potential growing customer performance requirements. As shown in Figure 8.2.3-1, combinations of these enhanced wide body booster cores with the evolved upper stage can produce a set of affordable heavy-lift solutions that deliver over 100 mT to LEO. Depending on customer requirements, one can either cluster five wide-body boosters to deliver 107 mT to LEO or, if even more performance is required, four wide body boosters can be clustered around an 8.4-m diameter core to deliver 140 mT to LEO. Both of these booster combinations are paired with the evolved upper stage and a new 8.4-m (27.6-ft) payload fairing.

The 5-m diameter booster tank is derived from Delta IV’s existing 5-m tank and is powered by a pair of RD-180 engines. The 8.4-m diameter core is derived from the Space Shuttle’s external tank and powered by five RD-180 engines. Both the 5-m and 8.4-m diameter booster cores can fly either as a single core, with strap on Aerojet SRBs (1 to 6), or as multi-core combinations with the use of either two or four 5-m, wide-body liquid rocket boosters (LRBs). The single core configurations provide ideal, highly reliable launch vehicles capable of supporting launch of large crew capsules. These super-heavy Atlas derivatives allow Atlas to support a broad payload range (9mT to 140 mT to LEO) with a common vehicle family.
2rzsao7.jpg
 

Urwumpe

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Why do they want to use dual RD-180 and not a single RD-170 in the plan?
 

simcosmos

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Why do they want to use dual RD-180 and not a single RD-170 in the plan?

As far as I’m aware, the RD-180 was chosen for the current Atlas V vehicles because it was the most cost-effective engine for the expected mission requirements: for extra performance the cores can support solid boosters, the Centaur can be fielded with an extra engine (as long as someone pays for that development on current vehicles) and there is also the AtlasV Heavy lift configuration (which passed CDR and uses very little changes to existing components, at least when comparing with Delta IV case, although it is expected that with RS-68A implementation the Delta cores might become slightly more common than what happens nowadays).

Nice threads for EELV Evolution / AtlasV / Delta IV related information:
http://forum.nasaspaceflight.com/index.php?topic=19972.0
http://forum.nasaspaceflight.com/index.php?topic=6479.0
http://forum.nasaspaceflight.com/index.php?topic=9350.0



For the eventual AtlasV evolution path it might then be natural to continue assuming the RD-180. A special wider / shorter core could be implemented (for a single RD-180, it is shown in the evolution picture) but the main plan would be really to field a new common core, with two RD-180: this provides engine out for crewed vehicles for the first stage (and upper stage could have that engine out feature too) and keeps using a known hardware component (the Rd-180) for such new cores (instead of requiring extra propulsion considerations).

Of course that some variation of a single RD-17X could do the same job (at least in terms of performance) but that would mean yet a new contract, etc: under current reality, there are already many RD-180 in storage and/or ordered and there was also some information exchanged that, in theory, could allow the ‘domestic’ (United States of America) production of the RD-180 (such domestic production capability seems to have been originally a requirement for all EELV but only Delta met that goal, with the development of the RS-68)… Although it is also true that there are several opinions about the true verification of such capability for the RD-180 (would the resulting RD-180 be really equal to the original version in terms of mass and performance? and how about the price?)… There are also opinions that mention that would probably be better to have a fresh start, with a more powerful engine – with thrust then at ~F1-A or RD-17X levels - as long as (and this is kind of important) there is money to pay for such 100% new development (instead of continuing to pay or trying to replicate the RD-180).


Regarding bringing such plans into Orbiter: I’m planning to implement some of the AtlasV Evolution stuff into an eventual future release (whenever that happens) of NASA VSE SC addon although will probably use the older ~5.5m diameter plans (current real life iterations assume the cores / upper stages at ~5m diameter). In fact, have played a little with that but will probably stop at the single core of Phase2 (and leave heavier lift for a SDLV with a later kerolox booster upgrade). Some older previews of AtlasV Evolution are on my flickr space (about the conceptual utilization of up to the three-core Phase2 variant (with options for max. performance) in a previous / outdated MarsDrive DRM):


3179561329_e3840ed241_o.jpg




The hardest thing to find are estimations about the mass of the new core (upper stages and stuff such as interstage / PLF are +/- easy… although the core could in part be estimated with some scaling). Haven’t really implemented performance neither studied ascent trajectory constraints. Because I take virtually forever to fine-tune / share the toys that have in 'simcosmos' development archives (and because will not go much beyond Phase2) it might be better to not wait for me!

As a final side note, something slightly similar (at least in concept) to AtlasV Evolution has been released by Kodiak:
http://www.orbiter-forum.com/showthread.php?t=13195#post142867


António
 
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Kyle

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The last 3 Atlas V HLV's require a new Launch Pad.. how about LC39A and B?
 

T.Neo

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Sure, if they're not scheduled for demolition...
 

Urwumpe

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Well, the thing is just that a single RD-170 is essentially two RD-180 with a common turbo-pump. That would mean further cost and weight savings, and the RD-170 is flight certified and at least practically available in the USA (because of Sealaunch).

Of course, it would mean a new contract for the delivery of the engines, but there are advantages, and the effort for getting a new engine delivery deal done would be likely small enough for the gains.

Since the engines share components, a RD-170 deal would also have positive impacts on the RD-180.
 
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