Wednesday, October 1, 2008

SpaceX and RLV

SpaceX has done an amazing job of creating and flying a new launch system from scratch. There have been a few snipers criticizing their designs, procedures, schedules, and anything else the anonymous crowd can dream up. The fact remains that a relatively new team has done a tremendous job with less cash expended than many traditional launch people thought possible.

The very excellence of SpaceX points out one of the fundamental differences between ELVs that might be reusable, and RLVs designed around continuing operations with each airframe. A really good company splashed 3 vehicles before getting one in orbit with a test payload. The bottom line is that they are building at least 5 complete launch vehicles before collecting revenue from a single flight.

I am an RLV fan. If it were to cost 5 times as much to build an equivalent payload RLV as a Falcon 1, then they would be equal in total cost and revenue returned after the first completed revenue RLV flight. It will almost certainly cost more than 5 times as much money per airframe for the RLV vehicles, the question is "how much more?". Just on operations, weekly flight RLV could fly 50 times a year, so even if it were 50 times as much per airframe, it just might be worthwhile to build the RLV for the revenue it would return the second, third, and fourth years.

That would be if all else were equal. It is not. Development money up front is frequently far more important than operational costs in the misty future. The Shuttle is the classic example of skimping on development at the cost of unaffordable operations. The conventional wisdom is that it will cost far more to develop a minimal RLV than a conventional ELV with tried and true technology.

The conventional wisdom has a few problems. Testing is the major cost in spacecraft development. An RLV test schedule could have flown bunny hops with minimum propellant of the first stage only to characterise early flight handling. Falcon flight 1 was flown all up for good reason, once it leaves the pad, it is expended whether it reaches orbit or the next island. If it is not coming back, why waste the airframe on a tenth of a test. The problems of flights two and three might have been ironed out without losing an airframe if tiny steps could have been taken.

It is my opinion that a sufficiently funded and well run RLV vehicle development effort could easily cost less than 10 Falcon 1s. It could afford to fly dozens of dummy payloads to make very sure of most uncertainties. At the end, it could be superior competition to a vehicle type that has flown a total of ten times with 70% mission completion, or even 100 times with 97% mission completion.

No comments: