Estimate how long a battery-powered satellite can operate an observation payload while supporting the spacecraft bus and preserving an energy reserve. The calculation exposes both usable observing time and total load, which helps mission planners compare payload modes before committing to a pass schedule.
Available energy = nominal battery × usable depth × (1 − reserve). Observation time = available energy ÷ (bus load + payload load).
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 5,000 Wh battery at 70% usable depth with a 15% reserve provides 2,975 Wh. A 180 W bus plus 420 W payload draws 600 W, allowing about 4.96 hours.
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. |