Ares 5, done faster and cheaper
Under the current iteration of NASA's moon plan, the agency will be saddled with the costs of building two all-new rockets over the following decade. In light of the agency's inability to get a budget increase consistent with this plan, it makes the most sense to drop one of the rockets and use the survivng rocket for an earth-orbit rendezvous mission plan.
I've been against Ares I from the start, referring to it as "the stick" last summer. I think there is room for Ares V, but only if the costs and schedule can be kept in check. That will only happen if performance is sacrificed. In other words, I think that Ares 5 should be faster and cheaper, but not better (at least in terms of throw weight.)
How do we accelerate Ares 5 development? While I would keep the RS-68 engines, I would not introduce the 10-meter first stage, I would delay development of the EDS upper stage, and I wouldn't use the five-segment solids. It won't require much, if any, new tooling if they stuck with the shuttle's 8.38-meter tank and four-segment solids. It would be easy from a manufacturing standpoint to make the LOX tank for the Ares V (it's just a shorter version of the LH2 tank,) and it would be easy to manufacture a longer first stage if needed. However, I'm willing to trade performance to get this rocket built quickly and within budget.
The vehicle I propose (RS-68 engines, 8.38 meter tank, 4-segment SRB's, axially-mounted CEV, and no upper stage) will have fairly underwhelming performance, perhaps putting only 60 metric tons into low earth orbit. Still, that's over twice the capacity of Ares I or a heavy EELV. It also ensures that an economy of scale will be necessary for a lunar mission. NASA's maximum proven flight rate was 9 shuttle missions during a year (1985.) NASA estimated that it could potentially launch 14 missions per year, assuming that no time was wasted with an orbiter in the Orbiter Processing Facility. If the Ares 5 program costs $4 billion per year like the shuttle does and launches 14 times, it will cost $286 million per launch.
NASA will still need to develop the EDS upper stage and the lander (which has now taken over the lunar orbit insertion burn from the EDS,) but the cheaper, faster Ares 5 that I describe could at least be flying CEV missions to the ISS before the other elements are ready.
An open question is whether the lighter, underperforming Ares 5 in this proposal would really be an "Ares 4." It would seem that the fifth engine would be overkill, considering that this configuration will be similar in mass to the existing shuttle. I am tempted to retain the fifth engine, but only to preserve the option for adding the EDS as an upper stage at a later date. If the fifth engine is omitted, it would save NASA $20 million per launch.
NASA Watch also reports that NASA is looking back to the Saturn V's third stage (S-IVB) for the EDS. If anything, the S-IVB can suggest technical solutions for the EDS (and the second stage of Ares I, if it survives,) but can't be put back into production. The S-IVB was built by Douglas Aircraft in El Segundo, and the 6.61-meter tooling was probably scrapped long ago. Still, the unique common bulkhead employed by the S-IVB is worthy of consideration. However, reusing the Shuttle ET tooling for the EDS might be the cheapest way of approaching the problem.
I've been against Ares I from the start, referring to it as "the stick" last summer. I think there is room for Ares V, but only if the costs and schedule can be kept in check. That will only happen if performance is sacrificed. In other words, I think that Ares 5 should be faster and cheaper, but not better (at least in terms of throw weight.)
How do we accelerate Ares 5 development? While I would keep the RS-68 engines, I would not introduce the 10-meter first stage, I would delay development of the EDS upper stage, and I wouldn't use the five-segment solids. It won't require much, if any, new tooling if they stuck with the shuttle's 8.38-meter tank and four-segment solids. It would be easy from a manufacturing standpoint to make the LOX tank for the Ares V (it's just a shorter version of the LH2 tank,) and it would be easy to manufacture a longer first stage if needed. However, I'm willing to trade performance to get this rocket built quickly and within budget.
The vehicle I propose (RS-68 engines, 8.38 meter tank, 4-segment SRB's, axially-mounted CEV, and no upper stage) will have fairly underwhelming performance, perhaps putting only 60 metric tons into low earth orbit. Still, that's over twice the capacity of Ares I or a heavy EELV. It also ensures that an economy of scale will be necessary for a lunar mission. NASA's maximum proven flight rate was 9 shuttle missions during a year (1985.) NASA estimated that it could potentially launch 14 missions per year, assuming that no time was wasted with an orbiter in the Orbiter Processing Facility. If the Ares 5 program costs $4 billion per year like the shuttle does and launches 14 times, it will cost $286 million per launch.
NASA will still need to develop the EDS upper stage and the lander (which has now taken over the lunar orbit insertion burn from the EDS,) but the cheaper, faster Ares 5 that I describe could at least be flying CEV missions to the ISS before the other elements are ready.
An open question is whether the lighter, underperforming Ares 5 in this proposal would really be an "Ares 4." It would seem that the fifth engine would be overkill, considering that this configuration will be similar in mass to the existing shuttle. I am tempted to retain the fifth engine, but only to preserve the option for adding the EDS as an upper stage at a later date. If the fifth engine is omitted, it would save NASA $20 million per launch.
NASA Watch also reports that NASA is looking back to the Saturn V's third stage (S-IVB) for the EDS. If anything, the S-IVB can suggest technical solutions for the EDS (and the second stage of Ares I, if it survives,) but can't be put back into production. The S-IVB was built by Douglas Aircraft in El Segundo, and the 6.61-meter tooling was probably scrapped long ago. Still, the unique common bulkhead employed by the S-IVB is worthy of consideration. However, reusing the Shuttle ET tooling for the EDS might be the cheapest way of approaching the problem.
posted by Mr. X at
5:04 PM
