Before a satellite is allowed on a rocket, it has to prove that it will survive the launch and work in space. Environmental testing simulates the loads of the ascent and the conditions in orbit on the ground. Launch providers usually require evidence of these tests, so they belong in every project schedule from the start.
Mechanical tests
- Vibration testing: the satellite is mounted on a shaker table and exposed to sine and random vibration that represents the launch environment of the chosen rocket.
- Acoustic testing: larger satellites are placed in a reverberant chamber and exposed to the intense noise generated during lift off.
- Shock testing: checks that the satellite tolerates the short, sharp loads from stage and fairing separation and from its own release.
Thermal vacuum testing
In a thermal vacuum chamber, air is pumped out and the satellite is cycled between hot and cold extremes while it operates. This test shows whether the thermal design works and whether components function reliably in vacuum. The cover image shows the NASA and ISRO radar satellite NISAR during such a test at an Indian facility.
Electromagnetic compatibility
EMC tests verify that the satellite's electronics do not interfere with each other or with the launch vehicle, and that they are not disturbed by the rocket's own radio systems.
Qualification and acceptance
Test programmes distinguish between qualification tests, which use higher levels to prove the design, and acceptance tests, which confirm that a flight unit was built correctly. Small satellite projects often use a protoflight approach, in which the flight unit is tested at intermediate levels and durations to save time and cost.
How the launch vehicle affects testing
Every rocket has its own user manual with load levels and test requirements. If a satellite switches to another rocket, its existing test results may not cover the new environment. Operators who want flexibility should test to an envelope that covers several candidate launchers.
Related reading
- The Launch Campaign: What Happens to a Satellite at the Launch Site
- Payload Fairings, Adapters and Separation Systems: The Launch Interface Explained
- CubeSats Explained: Sizes, Standards and How They Reach Orbit
Sources
Cover image: The NISAR satellite after thermal vacuum testing at an Indian spacecraft facility. Credit: NASA/JPL-Caltech (PIA26114), public domain.