Mars mission duration

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Manned missions to Mars split in two different types. They are named after astronomical names of the moments of departure of the ships from Mars: conjunction and opposition. Opposition type mission have less total time but more time spent travel in weightless conditions, conjunction mission have much more time spent in Mars surface.

Conjunction and opposition mission trajectory.
Conjunction and opposition mission trajectory.

Comparison conjunction and opposite mission type:

Mission type [1] Total mission duration, days Earth-Mars trip, days Time spent at destination Mars-Earth trip, days Total ∆V, km/s Trans-Mars Injection, km/s Mars Orbital Insertion, km/s Trans-Earth Injection, km/s
Conjuction 1005 198 558 197 2.81 0.50 1.25 1.06
Opposition 560 177 40 342 5.69 0.61 1.75 3.33
Conjunction and opposition Mars mission duration.
Conjunction and opposition Mars mission duration comparison.

Mars have very elliptical orbit relatively to Earth. The eccentricity of the orbit of Mars is 0.0935 – second among the planets after Mercury. Launch windows to Mars opened approximately every 2.14 years (26 months) but because of Mars orbit eccentricity and differences in his orbital speed this time changes a little bit from time. The same way changes a distance between Earth and Mars in moment of oppositions, time travel to Mars and necessary for this delva-V.

Mars Oppositions from 1995 to 2007 year
Mars Oppositions from 1995 to 2007 year

Examples of the near future missions opportunities

Mars short-stay (opposition) mission:

Departure Date [2] Mission Duration (years) Time spent at destination Injection (C3/∆v), km/s Post-escape ∆v, km/s Destination Aerocapture (∆V/Inertial), km/s Earth Aerocapture (∆V/Inertial), km/s
19-Jul-2020 1.50 1 month 14.5/3.87 2.80 1.41/6.2 0.86/11.8
22-Oct-2021 1.39 1 month 14.4/3.86 2.80 3.48/8.2 0.47/11.4
14-Sep-2023 1.64 1 month 25.7/4.34 0.99 3.29/8.0 0.48/11.4

Mars long-stay (conjunction) mission:

Departure Date [2] Mission Duration (years) Time spent at destination Injection (C3/∆v), km/s Post-escape ∆v, km/s Destination Aerocapture (∆V/Inertial), km/s Earth Aerocapture (∆V/Inertial), km/s
4-Aug-2020 2.53 1.40 years 15.7/3.92 1.45 0.70/5.5 0.80/11.7
15-Sep-2022 2.63 0.85 years 14.4/3.86 0.94 0.88/5.6 0.50/11.4
14-Oct-2024 2.62 0.87 years 12.1/3.76 0.82 0.73/5.5 0.58/11.5

References

  1. Bryan Mattfeld, Chel Stromgren - Trades Between Opposition and Conjunction Class Trajectories for Early Human Mission to Mars in AIAA Space 2014; 4-7 Aug. 2014; San Diego, California
  2. 2.0 2.1 Cyrus Foster, Matthew Daniels - Mission Opportunities for Human Exploration of Nearby Planetary Bodies in AIAA SPACE 2010 Conference & Exposition, 30 August - 2 September 2010, Anaheim, California ISBN AIAA 2010-8609