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Piloted Mars missions using cryogenic and storable propellantsThe 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.
Document ID
19930068906
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Striepe, Scott A.
(NASA Langley Research Center Hampton, VA, United States)
Desai, Prasun N.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1993
Subject Category
Astronautics (General)
Report/Patent Number
AAS PAPER 93-636
Report Number: AAS PAPER 93-636
Meeting Information
Meeting: AAS and AIAA, Astrodynamics Specialist Conference
Location: Victoria
Country: Canada
Start Date: August 16, 1993
End Date: August 19, 1993
Sponsors: AIAA, AAS
Accession Number
93A52903
Distribution Limits
Public
Copyright
Other

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