Electric Space Tug: Multi-Propellant Analysis

Comparison of Xenon, Krypton, and Argon for a 1,000 kg payload mission to Lunar Flyby (TLI) and return.
System: 10x Turion TIE-20 GEN2 Thrusters (20kW Total Power).

1. Performance & Time Estimates

ISP and Thrust are scaled based on atomic mass. Lighter gases (Argon) have higher ISP (efficiency) but lower Thrust (slower acceleration) for the same power input.

Parameter Xenon (Xe) Krypton (Kr) Argon (Ar)
Atomic Mass 131.3 u 83.8 u 39.9 u
Estimated ISP 4,500 s 5,600 s 8,100 s
Total Thrust (10x Cluster) 550 mN 440 mN 305 mN
Est. Outbound Trip Time
(LEO to TLI)
~240 Days
(0.65 Years)
~300 Days
(0.82 Years)
~450 Days
(1.23 Years)
Time Constraint Check PASS PASS FAIL (>1 Year)

2. Mass Budget

Calculated for total ΔV = 14,000 m/s (7km/s out, 7km/s back). Argon requires significantly less reaction mass due to high ISP.

Component Xenon Mass Krypton Mass Argon Mass
Reaction Mass (Outbound) 350 kg 285 kg 185 kg
Reaction Mass (Return) 126 kg 95 kg 55 kg
Total Reaction Mass 476 kg 380 kg 240 kg
Tank Mass (15% of fuel) 72 kg 57 kg 36 kg
Tug Dry Mass (Hardware) 630 kg 630 kg 630 kg
Payload 1,000 kg 1,000 kg 1,000 kg
TOTAL LAUNCH MASS 2,178 kg 2,067 kg 1,906 kg

3. Cost Estimates

Assumptions

Comparison: Cost per kg of Payload Delivered

Values represent the Total Cost / 1000.

Scenario Xenon System
($1.43M fuel cost)
Krypton System
($152k fuel cost)
Argon System
($4.8k fuel cost)
1) Disposable Tug (Hardware + Fuel + Launch included)
High Launch Cost
($1000/kg)
$8,606 / kg $7,219 / kg $6,911 / kg
Low Launch Cost
($200/kg)
$6,864 / kg $5,565 / kg $5,386 / kg
2) Reusable Tug (Fuel + Launch of Fuel + Launch of Payload only)
High Launch Cost
($1000/kg)
$2,904 / kg $1,532 / kg $1,245 / kg
Low Launch Cost
($200/kg)
$1,723 / kg $428 / kg $259 / kg
Conclusion: