Feasibility improvement of non-ablative lightweight TPS for mars aero-flyby sample collection mission

The concept of Non-Ablative Lightweight Thermal protection system (NALT) is proposed for the nest Mars exploration mission in Japan. The NALT consists of the C/C composite skin, insulator tiles and the honeycomb sandwich panel. By the dust collision tests during the heating, it was found that the entry vehicle using the NALT aeroshell could survive the Martian dust storm environment even if the C/C composite skin would not be coated with SiC. The bread board model (BBM) of NALT with the diameter of 600mm was developed to examine the technical difficulties in the development of the flight model of NALT. By the inspection using X-ray CT, it was fund that small separation points were partially observed between the C/C composite skin and the insulator tiles. Using the NALT BBM, the thermal vacuum test was carried out to verify the functional performance of NALT under space condition. It was found from the X-ray CT that the small separation points inside the NALT BBM did not propagate any more by the severe temperature differences during the thermal vacuum testing. The vibration test of NALT BBM was also performed to examine tolerance of NALT against vibration environment during the launch. It was found that no serious damage was observed for the NALT BBM after the testing.