[FPSPACE] NASA's plans for CEV and heavy lift launcher
zirconic1 at earthlink.net
Wed Jul 6 18:41:55 EDT 2005
From: Frank Johnson <fjohnson3 at gmail.com>
Sent: Jul 5, 2005 1:46 PM
>As a taxpayer, I would rather see the exploration architecture designed
around the Delta/Atlas EELV boosters. The development costs for these
rockets have already been sunk and their production lines seem to have
1-Utilizing either of these vehicles for the lunar mission requires further development of some sort. In the case of launching the CEV, it will require some kind of human rating of the vehicle. I have yet to see a good description of what the heck that means, but I assume that it means adding additional sensors and changes to the flight termination system and stuff like that. In the case of turning either vehicle into an HLLV, it requires further development. But both manufacturers acknowledge that there are upper limits to how big they can make their rockets. At some point you need to start over (i.e. an entirely new vehicle), or start with a different set of assumptions (like utilizing shuttle hardware).
2-How much extra capacity do they actually have? I looked at some internal NASA estimates of rocket vehicle use from 2002 and it was rather surprising. If you assume a robust lunar exploration goal, then you may actually _exceed_ the production line capabilities for at least one of these rockets. The architecture requires more core vehicles than they can build.
2.5-How does the recent decision to consolidate production of both vehicles affect the capacity issue? With them both being built in the same facility, is there excess capacity for either vehicle? I assume that there is still _some_ excess capacity. But is there enough?
>Some, such as Robert Zubrin, point out that an EELV-based
exploration architecture with more launches per mission carry higher risks
from launch failure. I think that an economic argument can be made that the
costs of insurance and replacement payloads will be less than the cost of
developing a substantially new shuttle-derived launch vehicle.
The government doesn't buy insurance. It "self-insures." This means that it pays the full cost of failure. And it is hard to see how it could do it otherwise for these payloads. The government can to some extent get insurance for more commercial type payloads (like military comsats), but where is it going to find an insurance company willing to insure a billion dollar spacecraft and launch?
But here's where I think you get to a real thorny issue--is there _any_ room for failure at all? If you lose a single big payload on a Shuttle-C, you're in deep trouble. But if you lose a single medium-size payload on a big EELV, you're still probably in deep trouble. Look at the ISS construction manifest. Which of the past dozen or so shuttle ISS construction missions could you spare without significantly affecting the overall construction? Lose a solar panel or a habitation module or any important piece of equipment and you are still set back by years.
(One minor additional note: Zubrin did not only refer to launch failures, but other mission failures associated with complexity, such as a docking failure.)
In addition, going to many more, smaller flights adds tremendous complexity. I have not seen much public discussion of t/Space's lunar exploration proposal. They propose fifty--yes, FIFTY--launches for each lunar landing. Zubrin discussed (and I have not yet seen any information on what he was discussing) a NASA moon architecture that called for four EELV launches per mission (one lander, one crew vehicle, two TLI stages). He rightly pointed out that basing the architecture on multiple launches adds some major constraints. It prevents you from using hydrogen propellant, for instance. And it requires parallel launch processing for several vehicles.
All that said, I strongly believe that there are real answers to some of these questions. And we seem to be discussing the questions without anybody getting the answers. Here are some of the questions:
-what is the maximum capacity for EELV production?
-what is the marginal cost for EELV launches at several different launch rates?
-what are the anticipated development costs for a Shuttle-C?
-what are the marginal costs for a Shuttle-C?
(note that this one should be relatively simple to calculate to close approximation: simply take the current per-year cost of the Shuttle and then subtract a major fraction of the costs of the Orbiter, leaving at least some of that money to account for the costs of the SSMEs).
-what are the costs of human-rating an EELV?
-what are the marginal costs of an SRB-derived booster?
(note that this should also be relatively easy to calculate: simply take the cost of a single SRB and then add in the additional costs to stick humans on it, such as a second stage).
I just find this frustrating. There should be answers there, and I hope that NASA is making decisions based upon sound cost accounting, rather than simply gut instinct.
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