1. The basic mission used herein utilizes two pre-deployed missions in the 2035 Earth-Mars opportunity to preposition a cargo lander on Mars surface and a crew lander in Mars orbit. The crew mission begins at the start of the 2037 opportunity. Multiple Earth launches are required for each mission leg, thus multiple Earth orbit rendezvous (EOR) are required. Because the crew lander is pre-deployed to Mars orbit, the crew must perform a Mars orbit rendezvous(MOR) prior to descent to the surface. Thus, the basic mission mode used inthisexample isEOR-MOR.
2. Table 4. Departure Date Ranges for 2037Mars ReferenceMission
3. EXTRAis capable of performing mission design by utilizing its enumerative mode where all possible departure dates and flight times (over user-specified ranges) are calculated. In this example, the outbound cargo mission, the outbound crew mission, and the inbound crew mission opportunities and departure windows are determined over the 2030 to 2045 timeframe, covering a complete 15-year Earth-Mars cycle. The cargo mission utilizes propulsive Earth departure with aerocapture Mars arrival, the outbound crew mission utilizes propulsive Earth departure with propulsive Mars arrival, and the inbound crew mission utilizes propulsive Mars departure with direct Earth aero-entry. These opportunities (departure dates) and windows (size of the date range for a given opportunity) are selected assuming: the TMI V is less than 4.5 kilometers per second (km/s); the MOC V is less than 2.5 km/s; and the TEI V is less than 2.5 km/s. These values are selected to narrow the range of mission departure dates to those where the mission performance required and departure window size are reasonable. However, the design V must be traded against the size of the departure window as decreasing design V decreases the size of the departure window. The 2037 crew mission opportunity was selected for further missionoptimization and isshown in Table 4.
4. V (m/s) Ispv (sec) V (m/s) Ispv (sec) LEO Rendezvous NTR - 150 335.9 TMI NTR 3900 915.0 - Disposal NTR - 100 335.9 MOI - Aerocapture MAB - 150 335.9 De-Orbit MAB - 15 335.9 Entry/Descent MAB - 50 335.9 Landing MDS 500-800 352.4 100 334.5