Environmental Testing Master Class for Aerospace 2022

Certification and qualification of products require specific dynamic tests using external excitation - shock, vibration, and noise. Understanding the key parameters behind any control algorithm is critical to a successful test.

Mechanical qualification testing takes place on a very expensive model/prototype or the actual spacecraft, with a significant risk of damage to the hardware. We will discuss how this can be done with full confidence without compromising the integrity of the scarce and expensive engineering qualification model or the actual flight model.

The purpose of mission synthesis is to design the optimal test. A balance between severity and accuracy needs to be found. The test should give confidence that it is severe enough to produce those failures likely to occur under normal operating conditions while avoiding too high-test levels that tend to result in costly over and under-testing design of the item. The goal of mission synthesis is to design the optimal test. A balance between severity and accuracy needs to be found. The test needs to give the confidence that it is severe enough to produce those failures that are likely to occur during normal operating conditions.

The noise levels generated at launch can reach levels up to 146dB or higher inside the fairing and cause structural damages and jeopardize the functionality of instruments and subsystems. Therefore, launcher authorities require spacecraft also to be qualified for acoustic loading. Both traditional (RFAX) and the new testing method (DFAN) will be discussed.

The need for time-efficient testing procedures and the guarantee of accurate replication of the operational environment are two driving factors in the environmental testing community. MIMO control strategies for dynamic environmental testing can provide the required flexibility to design test campaigns that safely comply with these two key drivers.

To understand the structural dynamics of a spacecraft, the program sometimes requires a Modal survey test. This test aims at test-validating the spacecraft Finite Element structural dynamics model. This model is necessary for the Launcher Coupled Loads analysis process, which assesses the risk of launch load damage. In the field of vibration testing, the interaction between the spacecraft being tested and the shaker used to perform the test is a critical issue, because the dynamics of the shaker often couples with that of the test object making its behavior during the physical tests unpredictable. Simulation methods such as “Virtual Shaker Testing” are being developed to be able to foresee these testing difficulties and take countermeasures before running the actual program.

High-end optical imaging sensors and lasers are used more and more in satellites. These sensors have high requirements in terms of stability to provide high-quality images. However, mechanical devices on the spacecraft such as reaction wheels for attitude control can cause micro-vibration disturbances leading to blurred images. Therefore, scientific and earth observation missions call for stringent requirements with regard to the micro-vibration environment on-board of a spacecraft. In this session, we will discuss traditional and novel experimental-based methods to assess the performance of micro-vibration sources.