- 著者
- Keiyu HANDA Masato FUNATSU Kenji SHIBUSAWA
- 出版者
- THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES
- 雑誌
- TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)
- 巻号頁・発行日
- vol.18, no.5, pp.209-215, 2020 (Released:2020-09-04)
- 参考文献数
- 14
- 被引用文献数
- 1
Recently, various unmanned and manned Mars exploration programs have been proposed. To send a space vehicle safely to the ground of Mars, the vehicle needs to be protected from the aerodynamic heating. The accurate prediction of the aerodynamic heating is important for the design of safe and light-weight thermal protection system. For the accurate prediction, it is necessary to simulate the plasma generated behind the shock wave and to clarify its internal state. To investigate the state of the plasma, spectroscopic measurement is useful. We performed the spectroscopic measurements of carbon dioxide (CO2) plasma generated using microwave discharge under the pressure condition during Mars entry. To investigate the basic characteristics of microwave-discharged CO2 plasma, the spectra of the radiation were obtained in the wavelength region of 200 to 800 nm. As a result, carbon monoxide (CO) fourth positive bands, CO third positive bands, CO Ångström bands, and atomic oxygen lines were observed. Electronic excitation temperature was also estimated by the Boltzmann plot method for the atomic oxygen lines.
- 著者
- Yusuke MATSUOKA Masato FUNATSU Takahisa KANEDA Yuki OYA
- 出版者
- International Symposium on Space Technology and Science
- 雑誌
- Journal of Evolving Space Activities (ISSN:27581802)
- 巻号頁・発行日
- vol.1, pp.93, 2023 (Released:2023-12-21)
- 参考文献数
- 9
When a sample return capsule enters the Earth's atmosphere, a strong shock wave is generated in front of the capsule and it receives severe aerodynamic heating. An ablation method is the effective thermal protection one to protect the capsule from the heating. In the future, capsules are expected to be larger and to increase reentry speed. Therefore, the capsules will be exposed to more severe aerodynamic heating. In this experiment, porous carbons with different pore diameters (5 μm, 10 μm, and 25 μm), and porous carbons impregnated with cyanoacrylate were used as test pieces. It was found that there were differences in wear time and wear behavior depending on the test pieces. Furthermore, the effective heat of ablation was calculated by conducting an experiment using an automatic position control system that can detect the tip of the test piece and control it to the target position. The effective heat of ablation of porous carbon impregnated with cyanoacrylate (5 μm) was about 2.8 MJ/kg.
- 著者
- Kenji SHIBUSAWA Masato FUNATSU
- 出版者
- THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES
- 雑誌
- TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (ISSN:05493811)
- 巻号頁・発行日
- vol.62, no.2, pp.86-92, 2019 (Released:2019-03-04)
- 参考文献数
- 20
- 被引用文献数
- 4
The spectroscopic measurement of low-pressure microwave-discharged nitrogen plasma was conducted in the wavelength region of 550 to 1070 nm. Radiation from the N2 first positive band of the Δv=0 to Δv=+4 band series and nitrogen atomic lines were observed. The experimental spectrum was compared with the theoretical spectrum, showing the effect of the predissociation of N2 B 3Πg state through N2 A′5Σg+ state and triplet splitting for the transition of 3Π to the 3Σ state. They agreed very well with each other for the Δv=0 to Δv=+2 band series, which consisted of the lower vibrational levels of Δv′=0 to 7, but did not agree well for the higher vibrational levels of Δv′=8 to 12 in the Δv=+3 and +4 band series. By comparing the band head intensity of the experimental and theoretical spectra, the experimental vibrational population on each vibrational level for the B 3Πg state was estimated to be a non-Boltzmann distribution at the higher vibrational levels. In addition, the theoretical vibrational population distribution in the B 3Πg state was calculated using a master equation, and then agreement between the experimental spectrum and the theoretical spectrum with the non-Boltzmann distribution obtained from the master equation was improved.