A reliable heat shield for ESA’s Space Rider mission

Fraunhofer EMI contributes to the ESA’s Space Rider re-entry design with hypervelocity impact tests and impact damage modeling.

In 2024, ESA wants to launch Space Rider, its first reusable uncrewed spacecraft. Currently, six missions are planned. At the end of each mission, Space Rider shall re-enter into Earth’s atmosphere and perform a soft landing. Prior to re-entry, while in orbit, the heat shield is impacted by space debris and micrometeoroid particles. Depending on size and position, the damage caused by those impacts can be negligible, or it can prevent a successful re-entry and be responsible for the loss of the vehicle.

To assess the actual risk posed by hypervelocity impact damage during the re-entry phase, damage models applicable to the re-entry heat shield material are required. Those significantly depend on the individual material properties. Since only few heat shield materials have been characterized in hypervelocity impact tests so far, no general damage models are available. The Italian Aerospace Research Center CIRA is heavily involved in the Space Rider development, one of its tasks being the design of the heat shield. To help CIRA with this task, Fraunhofer EMI investigated the behavior of their carbon-fiber-reinforced silicon carbide in hypervelocity impact tests. In those tests, we reproduced the actual on-orbit conditions in ground tests. We then used the test data to successfully develop the damage models required for risk analyses.

CIRA plans to expose some of the impacted samples to a simulated atmospheric re-entry in its Scirocco plasma wind tunnel. This allows to evaluate the combined effects of different environmental conditions. Such combined tests are currently only rarely performed. However, they provide valuable data, supporting the Space Rider mission as well as future space missions.