Why Bother Launcher Gary Snyder – June 2002

Why advanced launch technology is a waste of time at the present.

A quick enumeration of advanced launch technology includes: Electromagnetic accelerators, Balloons, Air breathers, Towed and Air Re-fuelers, Tethers, Lasers, and Nuclear engines. All these technologies purport to save propellant and thereby lower launch costs but ....

Consider an example, the Saturn V launch vehicle used to place Skylab into low Earth orbit. Similar vehicles, with the third stage, propelled the Apollo lunar landing missions. The Saturn V Payload Mass is 118000 kg. Delivered to: 185 km Orbit at a 28.0 degree inclination.

Stage Number 1:. Saturn 1C

Gross Mass: 2286217 kg. Empty Mass: 135218 kg.

Propellant Mass: 2150999 kg O2/Fuel Ratio: 2.27 (F-1 Engine)

Propellant Mass LOX: 1493201 kg Mass Kerosene 657798 kg

Stage Number 2:. Saturn II

Gross Mass: 490778 kg. Empty Mass: 39048 kg.

Propellant Mass 451730 kg O2/Fuel Ratio: 5.50 (J-2 engine)

.Propellant Mass LOX 382233 kg Mass LH2 69497 kg

Stage Number 3:. Saturn IVB

Gross Mass: 119900 kg. Empty Mass: 13300 kg.

Propellant Mass 106600 kg O2/Fuel Ratio: 5.50 (J-2 engine)

Propellant Mass LOX 90200 kg Mass LH2 16400 kg

(Technically not used on Skylab – but throw it in for extra cost)

Total all stage Propellant masses 2709329 kg

LOX:1965634 kg Kerosene:657798 kg LH2:85897 kg

Estimated Current Price of Propellants

LOX $0.055/kg (Ref 1) Kerosene $0.33/kg (Ref 2) LH2 $2.20/kg (Ref3

Estimated Current Cost of propellants $514156.61

LOX $108109.87 Kerosene $217073.34 LH2 $188973.40

Cost per kg payload from propellants $ 4.36/ kg

A current Book by D. Jenkins, develops the cost of $36,368/kg (Re 4). Thus:

The cost of propellants is 0.012% of the cost of the Saturn V vehicle. Propellant savings of advanced propulsion would be insignificant.

References:

Ref1 – Verbal communication with Launch personnel for cost of Liquid Oxygen at the Sea Launch Payload Processing Port was 2.5 cents per pound = $0.055 / kg

Ref2 = Retail price of Diesel Fuel at local gas station is 1.20/gallon. 6 lbs per gal and a tax of 30 cents. (1.20-0.30) / 6 = 0.15/lb retail price = $0.33/kg

Ref3 US department of energy lists the cost of generating hydrogen on site at $0.35/lb but liquid delivery raises this to approximately $1.00/lb = $2.205/kg

Ref 4 “Space Shuttle, The history of the National Space Transportation System, the first 100 missions” by Dennis R. Jenkins, 2001 PP 256 – (table)