The WP2 has been led by POLITO with the direct involvement of Deimos and DLR-Bremen. It has been run across the first 3 months of the project from beginning of December 2022 until beginning of March ( KO till 7th March). It came across eleven (11) weekly teleconferences during which the work performed in back-office was presented, analyzed, commented and reviewed by the core team of the WP2 as well as by the other partners of the consortium.
The core part of the WP2 was the Business Case analysis effort, that addressed potential applications strictly related with the exploitation of Inflatable Heat Shields in the space sector (with particular focus on LEO re-entry) as: recovery and reuse of launcher’s stages, recovery of ISS Cargo system and delivery of its payloads, and recovery of reusable satellites.
The BCA succeeded in:
• Identification and trade-off possible alternative applications of the Inflatable Heat Shields technology and down-selection the most promising one (the recovery of LV stages).
• Generation of the reference requirements for the WP3 to be started with an adequate set of inputs.
• Production of 2 deliverables successfully reviewed and submitted on the EC portal.
The WP3 kick-off occurred on March the 7th (see ppt of DLR, WT#11).
The first part of the WP3 was dedicated to engineering of the reference use-case system with implementation of the mission and system design loop bt the following main macro-activities:
I. Mission design
II. System engineering
III. Aeroshape design
IV. System synthesis
The Mission design addressed the study and consolidation of ConOps and trajectory analysis with identification of flight environment. Lops were done with support of Monte Carlo investigation.
Aeroshape design focused on exploration and consolidation of a baseline shape to fly the mission. Aerodynamics and Aerothermodynamics investigation were done, an AEDB was obtained through engineering tool and a trajectory analysis was done. Four options were compared w.r.t. flight corridor feasibility, complexity, mass impact. Only the first 2 options were chosen and for both executed an investigation based on CFD at ONERA. The Aeroshape was evaluated through Flying Quality Assessment.
Consideration on GN&C potential aspects were produced with respect to: Range capability and Entry guidance implementation.
The refence configuration underwent a design loop more detailed with CFD for axisymmetric AEDB/ATDB investigation providing input to trajectory analysis and structural/thermal design of the key elements of aeroshell re-sized with FEM models.
Mass/volume budget were produced for key sub-system and the system. A system synthesis was appointed to get: configuration, internal layout, mass/volume budget including MCI
The FSI loop was addressed in June, with the following main steps:
Analysis of literature and FSI general considerations
Definition of an FSI baseline strategy: key aspects, Key parameters to be monitored and convergence criterion, FSI meaningful flight conditions,
FSI implementation cycles: FEM preparation and first-guess, Loops execution at 2 different flight points (Mach 7 and Mach 13)
The FSI loop ended with:
Identification of a deformed shape to be tested in the wind tunnel H2K at Mach 7
A non deformed shape to be tested in the wind-tunnel TMK at Mach 3.5
Evaluation of specific phenomenology at Mach 13 around a deformed shape to be investigated in the future with a specific experimental activity
The FSI loop took more than 1 month involving CFD/FEM resources. It also allowed to steer some important aspects of the wind-tunnel test campaign. The FSI loop is deemed satisfactory.
All the WP3 deliverables have been produced as planned and uploaded on the EC portal end of July.
The WP4-WP5 preparation was taking the early stage of planning with definition of details for tests and implementation of needed procurements:
1) wind-tunnel models design and manufacturing for the WTT
2) refurbishment of Inflatable Structure demonstrator and test-rig
Afterwards a great test effort was carried out in parallel with:
A) execution of static and dynamic test on the ground demonstrator of the Inflatable Structure at premises of CIRA
B) execution of wind-tunnel tests in hypersonic and supersonic regimes , within two different wind tunnel facilities (H2K and TMK) at premises of DLR-Cologne using 2 different aero-models featuring the shape of the re-entry vehicle in its deformed and undeformed status.
The experimental results were used to revisit and improve numerical models (CFD, FEM) to increase their confidence level and as consequence their prediction capability.
The WP7 allowed to develop and validate a GN&C software for the control of re-entry of vehicles based on Inflatable Heat Shield technology .
The G&NC algorithms were verified in design environment (model-in-the-loop, MIL, then translated into a software that was validated in a simulated environment ((software-in-the-loop, MIL) , and at the end verified on a piece of hardware (on-board computer) to get final stage of validation as Processor in the loop (PIL).
The WP6 performed very well with a lot of dissemination actions , mainly publication and participation to scientific international events in the field of space access and re-entry. In addition, the WP6 has produced an outstanding document where it has been widely assessed the status of the technology after this propjet as well as the identification of potential delta-effort for future initiatives in order to completed the process up until TRL>7.
