| タイトル | Piloted Mars missions using cryogenic and storable propellants |
| 著者（英） | Desai, Prasun N.; Striepe, Scott A. |
| 著者所属（英） | NASA Langley Research Center |
| 発行日 | 1993-08-01 |
| 言語 | eng |
| 内容記述 | The paper presents an analyses of piloted long-duration stay Mars missions using a chemical or nuclear thermal propulsion Earth-departure stage, storable propellant Mars arrival and departure stages (to avoid propellant boiloff), and an Earth entry vehicle, conducted for three-year segments from 2000 to 2020. The study initially determines the minimum initial mass in low-Earth orbit (IMLEO) missions and then investigates their radiation exposure levels and Mars parking orbit selection. The impact of reducing the outbound (Earth-Mars) transfer time on IMLEO and predicted radiation exposure levels is included. The results indicate that a vehicle using an advanced chemical propulsion system (Isp = 480 s) for Earth departure is feasible throughout 2000-2020 with an IMLEO less than 640 metric tons, while an Earth departure stage using a nuclear thermal propulsion (NTP) system with Isp of 925 s is even more appealing with IMLEO's less than 405 tons. Vehicles with 875 and 825 s specific impulse Earth departure stages have only slightly higher IMLEO's than the advanced NTP system (10 and 20 tons higher, respectively). Reducing the time spent in space may not always result in a significantly reduced level of radiation exposure, especially if the mission encounter dates are changed to a less favorable period of the solar cycle. |
| NASA分類 | ASTRONAUTICS (GENERAL) |
| レポートNO | 93A52903
AAS PAPER 93-636 |
| 権利 | Copyright |
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