Flight unit considerations

This chapter explains only the different steps and precautions required during the flight unit manufacture, assembly and testing.

Vibration testing and bake-out process

After the assembly, the satellite hardware must pass through vibration testing to certify that it can handle the launch. The vibration profile to test for is usually given by the launcher company and is specific for form factors or weight and the type of vibration. While all the tests are required for certification, usually the most important vibration test is the sinusoidal with frequencies up to 100 Hz, due to the predominance on launch. Consulting SpaceX Rideshare Payload User's Guide, the structure should handle at least 1.5 g.

A vibe fixture was developed to couple the satellite with the vibration table, released on Fixtures. It is not recommended to use 3D-printed PLA as tends to damp higher frequencies and instead, consider alluminum for the case.

At last, the satellite goes through a bake-out process to accelerate outgassing, thus preventing contamination of the launcher pod and payload.

Day in the life testing

Another important test is made to evaluate long-period satellite functioning. The test is performed by leaving the satellite running outdoors for an entire day, if possible being hit by the sun, to charge with the solar cells, and protected by the rain, to prevent damage. By the end of the test, the satellite should be running as it was left, and the batteries voltage be higher than previously.

Assembly precautions

Before the procedure, drop and scrub the boards and its components with isopropyl alcohol (IPA). In this assembly procedure, more than required in engineering satellite units, the use of nitrile gloves and anti-static mat and wrist strap is very important. Although it is not mandatory, the assembly should be made in an ISO cleanliness certified room, if possible. Also, satellite transportation should be made inside an EMF protection bag, in a Nanuk case.

Loctite usage

On flight unit, Loctite 222 is used in all screw surfaces. Just a few drops are enough to provide additional strength and prevent unscrewing.

Windform rails

Instead of PLA rails, a carbon-fiber-reinforced polyamide material called Windform XT 2.0 was used for the rails. It provides improved specific strength and NASA outgassing certification.