Kakehashi, Faulty brazing in second-stage engine cooling system caused engine burn through and cable damage resulting in shutdown midway through the upper stage's second burn, leaving spacecraft in elliptical LEO instead of GTO. Spacecraft thrusters raised orbit enough to complete some communications experiments.
Cavitation in the first stage hydrogen turbopump impeller caused an impeller blade to fracture, resulting in loss of fuel and rapid shutdown of the engine at T+239 seconds. The vehicle impacted the ocean 380 km at the northwest of Chichijima.
A hot gas leak from one SRB-A motor destroyed its separation system. The strap-on did not separate as planned, and the weight of the spent motor prevented the vehicle from achieving its planned height.[1]
^Ryan, Dorothy (3 December 2020). "Lincoln Laboratory is designing a payload to integrate on Japanese satellites". MIT. Retrieved 29 April 2021. The laboratory is working with the Japanese National Space Policy Secretariat and Mitsubishi Electric Company to integrate state-of-the-art sensors on the newest satellites in the QZSS constellation, QZS-6 and QZS-7, which are scheduled for launch in 2023 and 2024, respectively.
^"技術試験衛星9号機（ETS-9）の開発状況について" [About the development status of Engineering Test Satellite No. 9 (ETS-9)] (PDF). MEXT (in Japanese). 28 June 2021. Retrieved 7 September 2021.
