Astronomy & space · lesson 2 of 4
Space missions, communications and measurement
A mission trades measurement goals against mass, power, thermal control, communications and trajectory constraints. No single orbit is best for every goal.
Learn the ideas
Prerequisites: Orbital basics, energy and signal travel time.
Mission design
A mission trades measurement goals against mass, power, thermal control, communications and trajectory constraints. No single orbit is best for every goal.
Communications
Signals travel at finite speed. One-way delay differs from round-trip delay, and data rate differs from propagation speed.
Remote sensing
An instrument measures a physical signal with finite resolution and uncertainty. Calibration converts measurements into interpretable estimates.
Reproducibility
Keep instrument configuration, units, timing conventions and processing steps with the data. These are part of the scientific result.
Worked examples
A spacecraft is 900000 km away. Use light speed 300000 km/s. Find one-way signal delay.
Delay=distance/speed=3 s.
3 s
A spacecraft is 900000 km away. Use signal speed 300000 km/s and neglect processing delay. Find round-trip signal delay.
A round trip covers twice the one-way distance.
6 s
Check your understanding
8 questionsDecimals or fractions are accepted for numeric answers. Proofs and written responses use sample answers and require human marking. This is practice, not a protected examination.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.