Build a first-order electrical power budget for a exoplanet transit mission. Combine instrument and spacecraft-bus loads, payload duty cycle, conversion losses, design margin, eclipse duration, and allowable battery depth of discharge.
Use the main result as a transparent first-order planning value. The supporting metrics expose intermediate quantities so assumptions can be checked and compared across scenarios.
This screening estimate does not replace an orbit-by-orbit energy balance. Include solar incidence, array degradation, battery efficiency, heater modes, safe mode, and recharge constraints in detailed design.
With a 180 W instrument at 65% duty, a 220 W bus, 88% efficiency, and 25% margin, average source power is 478.69 W. A 2-hour eclipse at 70% depth of discharge requires 1,367.69 Wh.
The dominant inputs are those used directly in the displayed formula. Change one input at a time to see its effect while holding the other exoplanet transit assumptions fixed.
Fields described as optional or overhead may accept zero. Physical quantities that appear in a denominator or define the mission scale must remain positive.
Only the contingency or efficiency explicitly entered is included. Add separate reserves for effects that are not represented by an input.
Detailed models include geometry, hardware modes, environmental conditions, correlated uncertainties, and organization-specific constraints that a screening calculator cannot capture.
Recompute the case with an independent tool, document every assumption and unit, test pessimistic and optimistic scenarios, and compare against subsystem or observatory requirements.
| Output | Use |
|---|---|
| Main result | Primary sizing or planning value |
| Supporting metrics | Trace the drivers behind the result |
| Interpretation | Identify what is and is not represented |