#3411 · Science & Engineering Tool

Exoplanet Transit Mission Requirement Calculator

Translate an exoplanet transit observing concept into measurable mission requirements. Estimate total samples, science data volume, observing duty, and campaign span from cadence, transit duration, target count, transit count, and data size.

Calculator

Campaign sampling assumptions
stars
Stars monitored in the campaign.
events
Complete events required for each target.
hours
In-transit time per event.
hours
Out-of-transit coverage around each event.
sec
Time between recorded samples.
MB
Stored size after onboard processing.
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How to use this calculator

  1. Enter mission or observing assumptions using the units shown.
  2. Use measured or requirement-level values and document their source.
  3. Select Calculate to update the main estimate and supporting results.
  4. Change one uncertain input at a time to explore sensitivity.
  5. Use Reset to restore the worked-example defaults.

Formula

Samples = targets × transits × (duration + baseline) × 3,600 ÷ cadence
Data = samples × MB per sample
Campaign span = observing hours ÷ duty fraction

What the result means

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.

The nominal span assumes a 35% usable observing duty cycle. Scheduling constraints, target visibility, calibration data, and redundancy must be budgeted separately.

Example calculation

For 40 stars, 3 transits each, 5 hours of coverage, and 60-second cadence, the campaign records 36,000 samples. At 2 MB each, that is 70.31 GB and 600 observing hours.

Tips for better results

  • Keep all inputs in the displayed units before comparing scenarios.
  • Run nominal, best-case, and worst-case values instead of relying on one estimate.
  • Carry extra margin only once; avoid embedding it in an input and adding it again.
  • Record instrument mode, environmental assumptions, and data-reduction choices.
  • Confirm the final budget with the relevant observatory, spacecraft, or subsystem model.

Frequently asked questions

What inputs most strongly affect the exoplanet transit mission requirement calculator result?

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.

Can I use zero for an optional mission requirement input?

Fields described as optional or overhead may accept zero. Physical quantities that appear in a denominator or define the mission scale must remain positive.

Does this exoplanet transit estimate include operational contingency?

Only the contingency or efficiency explicitly entered is included. Add separate reserves for effects that are not represented by an input.

Why might a detailed mission model differ from this result?

Detailed models include geometry, hardware modes, environmental conditions, correlated uncertainties, and organization-specific constraints that a screening calculator cannot capture.

How should I validate this result before using it in a design review?

Recompute the case with an independent tool, document every assumption and unit, test pessimistic and optimistic scenarios, and compare against subsystem or observatory requirements.

Result interpretation guide

OutputUse
Main resultPrimary sizing or planning value
Supporting metricsTrace the drivers behind the result
InterpretationIdentify what is and is not represented

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