Earth Entry Guidance

In the scope of the ESA project “New Guidance Schemes for the Terminal Area Energy Management (TAEM) of Atmospheric Re-entry”, the nonlinear guidance and control approach initially developed for Mars entry was adapted for an Earth re-entry. The scheme was applied to two types of Earth atmospheric entry missions (ISS and Lunar return missions), and a subscale Apollo-like vehicle was modeled.

The reference low-g (<3g) trajectories, which are especially challenging given the limited aerodynamic capabilities of the capsule, were optimised for both missions using the ASTOS software.

Despite these demanding requirements, the performance achieved by the nonlinear guidance scheme yielded further proof of both the validity and the performance of the proposed solution to the guided entry problem. In particular, lunar return trajectories all remained within a 2km circular radius, with >80% of cases within 250m.
The tasks involved in this project included:

  • Review of existing entry guidance schemes for low L/D vehicles
  • Trade-off and selection of the most promising solutions
  • Adjustment to original algorithm for compatibility with optimised trajectories
  • Comparative testing via 4DOF Monte-Carlo between a reference guidance and the new scheme