Estimate propellant needed for a space-telescope maneuver budget using the ideal rocket equation. Dry observatory mass, station-keeping delta-v, specific impulse, mission years, and reserve are kept explicit so propulsion growth can be compared with optical and instrument mass allocations.
Lifetime delta-v = annual delta-v × mission years. Ideal propellant = dry mass × [exp(delta-v ÷ (Isp × g₀)) − 1]. Loaded propellant includes the selected reserve.
Treat the main result as an engineering estimate based on the stated inputs. Compare it with the applicable mission requirement and retain enough traceability to update the result when assumptions change.
This calculator supports early trade studies and does not replace mission-specific simulation, environmental analysis, or professional engineering review.
A 6,500 kg telescope needing 4 m/s per year for 10 years with 220 s Isp requires about 121.6 kg ideally. A 20% reserve raises the load to about 145.9 kg.
It uses the values shown in the input panel and the formula stated on this page. It does not add hidden operational or environmental allowances.
Yes. Decimal values are accepted within each field’s displayed range, and calculations retain precision until the result is formatted.
Use a value justified by your project’s maturity, uncertainty policy, and verification plan rather than treating the default as a universal recommendation.
No. It is a first-pass estimate for trade studies. Verify the design with subsystem models, test data, and mission-specific constraints.
Zero is accepted where it represents a physically meaningful absence of load, loss, background, duty, or maneuver demand. Inputs used as divisors must remain above zero.
| Item | Use |
|---|---|
| Primary inputs | Enter values in the units printed beside each field. |
| Margin or reserve | Applied only where stated in the formula. |
| Displayed result | Rounded for readability; internal math keeps full precision. |