June 26, 2019, 9:45 am

FEES Qualification Test Campaign

Testing your satellite is essential if you want to make sure that the mission goes as planned during launch and operation phases. For this, we have adopted a double model strategy, which consists of a qualification and a flight model: here we will talk about the former model.

After the complete assembly and the Ground Support Equipment (GSE) being determined and produced, FEES has been transported to SERMS laboratory (Terni, Italy) for being subjected to 2 different tests:

  • Mechanical test: consists of different kinds and levels of vibrations which simulate the launcher environment.
  • Thermal-vacuum test: consist of a vacuum chamber, heated and cooled according to our specific temperatures, in order to simulate the orbital environment.

 

Mechanical test

In order to better reproduce the launcher conditions, an aluminum dummy mass, representing other satellites, has been produced and placed above FEES. During the launch, FEES and the other satellites will be integrated into the designated ejection POD: in the same way, FEES and the dummy mass have been put inside a functional model of the same POD, provided by GAUSS srl, and anchored to a steel plate fixture, specially designed to simulate the mechanical properties of the inside of the launcher and the shaker interface.

FEES with the fixture and POD upon the shaker.

Finally, this combination of units has been placed on the facility's shaker, which has been instructed to reproduce the launcher vibrations in terms of frequencies and time in the 3-axis. To better monitor the conditions and assess the fidelity of the tests, accelerometers have been put on each object, that is FEES, the POD and the steel fixture.

Thermal-vacuum test

FEES has been placed inside the facility's thermal-vacuum chamber for a cycling test, which consists on a number of cycles between extreme temperatures, typically from hot to cold. To make sure the satellite will be able to correctly function in orbit, the plateau temperature times have been doubled with respect to the orbit estimation. First, the air is removed so all the heat is handled through radiation, and then the rate begins according to the designated input.

FEES inside the thermal-vacuum chamber.

In addition, FEES has been switched on and off in real time, according to the schedule requirements, by means of an electronic board and the data stream has been saved: this includes different kinds of information regarding electronics and sensors.

Finally, FEES has been weighted and its mass compared to the initial one: this is done due to the necessity of obtaining the Total Mass Loss (TML), that is the mass which the materials "lose" due to the outgassing.

Results

Upon first inspection, it is evident that FEES has shown positive results for both tests: while it takes time to extract and analyze the detailed test results, it is easily understood that the Qualification Test Campaign has been passed.

There has been no physical damage to any part of the model, and the most critical components, for what concerns vibration and mechanical loads (e.g. iridium module, antennas and switches), have shown no stability issue. Regarding the thermal-vacuum, FEES has demostrated its capability to survive and work at the extreme temperatures (which respectively represent direct sunlight and eclipse) and during the transition phases. Moreover, the TML is undeniably within the acceptable value of 1%.

The firmware has been working flawlessly during all the designated operative simulations of both tests.

Since the qualification model has been assessed to be reliable during the tests, the flight model will be almost identical and will face another test campaign at acceptance level (that is, with lower mechanical and thermal loads compared to qualification).

Get in touch to receive
news and updates about
our services and products

Tankyou

We will keep you informed about our activities, projects and products.