Propulsion Economic Considerations for Next Generation Space Launch by Chris Y. Taylor 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit Ft. Lauderdale, FL July 12,

Estimate of Costs for a New Economical Space Launch Vehicle Cargo to LEO Current Technology Expendable Liquid Fuel

c = r λ c = specific cost ($/lb.) = Launch Cost/Payload Mass r= structure-payload mass ratio = Structure Mass/Payload Mass λ= structure cost ($/lb.) = Launch Cost/Structure Mass

Physics & Technology r= structure-payload mass ratio = Structure Mass/Payload Mass Vehicle r (to LEO) Atlas V 4002 Proton M2.2 Ariane 55.2 Space Shuttle12 Assume r=2 Economics & Management λ= structure cost ($/lb.) = Launch Cost/Structure Mass c = r λ

λ = λ r + (λ nr /a) λ = structure cost ($/lb.) = Launch Cost/Structure Mass λ r = recurring costs λ nr = non-recurring costs a= amortization factor  flight rate

λ r = λ vehicle + λ ops + λ risk + λ propellant λ vehicle = Cost of Vehicle Hardware λ ops = Cost of Operations λ risk = Cost of Risk λ propellant = Cost of Propellant

λ vehicle = f C hardware f= fraction of vehicle expended = 1 (completely expendable) C hardware = cost of hardware ($/lb) $1100 < C hardware <$2300 $1100 < λ vehicle < $2300

λ ops = L C labor L= labor intensity (manhours/lb) = Total Labor Hours / Structure Mass 1 < L < 20 (for current launchers) C labor = cost of labor ($/manhour) = $100 $100 < λ ops < $2000

λ risk ≈ P fail [C payload /r + (1-f) C hardware ] P fail = probability of failure 0.02 < P fail < 0.05 C payload = cost of payload ($/lb) = payload cost/payload mass ≈ $10,000 r = 2, f = 1 $100 < λ risk < $250 not including indirect costs

λ propellant = q C propellant q = Propellant Mass/Structure Mass = η/(1-η) = 9 (assuming η=0.9) $0.1 < C propellant <$0.25 $0.9 < λ propellant <$2.25

λ = λ r + (λ nr /a) λ nr = non-recurring costs $20,000 < λ nr < $120,000 (assuming R&D only) a= amortization factor  flight rate = 27 (10 yr. payback, 4 yr. r&d, flight rate of 27/6 yr, 0% interest & inflation) $750 < (λ nr /a)< $4500

Launch Costs

Reducing (λ nr /a) Reduce λ nr design for min. λ nr off the shelf evolutionary cost sharing

Reducing (λ nr /a) Increase a on orbit assembly cluster vehicles new markets

New vs. COTS Stage 1 Engine Trade COTS launcher: λ=$2,050, r=2, η=0.9, M s =100,000 lbs, Stage 1 I SP = 331s

Reducing λ vehicle λ vehicle = f C hardware Reusable (reduce f) Big Dumb Booster (reduce C hardware )

Effects of Staging on Cost 2 Stage Case, subscripts indicate stage number If λ 1 ≈ λ 2, then changes to r 1 or r 2 have the same effect. Changes to λ 1 have bigger effect than λ 2. Therefore, 2 nd stage should be expensive and light weight while 1 st stage is heavier and cheaper (big&dumb or reusable).

Conclusions Amortized non-recurring costs (R&D) are the biggest consideration in developing economic launch vehicles. Economical launch vehicles will make heavy use of COTS parts (esp. engines) and evolutionary development paths. New major propulsion systems will require much higher flight rates and/or non-space applications to economically justify development costs. For economical cargo launch, reusable first stages are justifiable before reusable upper stages are. Performance optimized vehicles ≠ cost optimized ones.

Selected Bibliography Griffen M.D. and Claybaugh, W.R., “The Cost of Access to Space”, JBIS vol. 47 pp , 1994 Whitehead, J.C., “Launch Vehicle Cost: A Low Tech Analysis”, AIAA paper , 2000 Kalitventzeff, B., “Various Optimization Methods for Preliminary Cost and Mass Distribution Assessment for Multistage Rocket Vehicles”, JBIS vol. 20, pp , 1965 Carton, D.S., and Kalitventzeff, B., “Effect of Engine, Tank, and Propellant Specific Cost on Single- Stage Recoverable Booster Economics,” JBIS vol. 20, pp , 1965 Wertz, J.R., “Economic Model of Reusable vs. Expendable Launch Vehicles”, presented IAF Congress, Reo de Janeiro, Brazil, Oct. 2-6, 2000 Worden, S., “Perspectives on Space Future”, presented 2003 NIAC meeting, Nov. 6, 2003, /library/fellows_mtg/nov03_mtg/pdf/Worden_Simon.pdf Griffen, M.D., “Heavy Lift Launch for Lunar Exploration”, presented U. of Wisconsin, Nov. 9, 2001, Chang, I.S., “Overview of World Space Launches”, Journal of Prop. and Power, Vol. 16, No. 5, pp , Sept.-Oct Claybaugh, W. R., Economics of Space Transportation AIAA Short Course, 2002 World Space Congress, Houston TX