Author Topic: Doing Both Conjunction and Opposition Class Missions  (Read 228 times)

Offline Darkseraph

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Could a Mars program benefit from doing both conjunction and opposition class missions concurrently rather than only performing one kind of mission?

Since both mission types send the payload at different times when the planets orbits are in completely different positions, does this actually open up more opportunities to send cargo than only once every two years often cited? Or am I missing something in my understanding of this?

Would the ability to send cargo more frequently help with the economics of systems like the Starship/Superheavy?
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." R.P.Feynman

Online ncb1397

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Re: Doing Both Conjunction and Opposition Class Missions
« Reply #1 on: 01/13/2019 05:21 pm »
One thing to consider is that the EVM trajectories arrive at similar times to the EM trajectories. For instance, here is a quick trajectory search from the AMES tool (

499,"Mars",,"6779 km",0,May-10-2018,Dec-04-2018,208,6.9,31,3.53,0.82,4.36,EM,
499,"Mars",,"6779 km",0,Aug-03-2020,Feb-27-2021,208,14.7,4,3.87,0.59,4.47,EM,
499,"Mars",,"6779 km",0,Jan-13-2016,Oct-11-2016,272,11,14,3.71,1.24,4.95,EM,
499,"Mars",,"6779 km",0,Apr-16-2015,Jun-21-2016,432,11.7,40,3.74,2.72,6.47,EVM,
499,"Mars",,"6779 km",0,Apr-05-2017,Apr-08-2018,368,21.2,10,4.15,2.34,6.49,EVM,

The first date is departure time, the second date is arrival time. The 2015 launch going via Venus arrives in June 2016. But the 2016 launch going direct arrives in October 2016 or a difference of 3.5 months. So, while this increases the launch cadence at earth, it hardly increases the arrival cadence. You still get arrival in 2016, 2018 and 2021 or roughly every 2 years. I guess the spread for 2018 is April vs December. So, more of a gap there.
« Last Edit: 01/13/2019 05:26 pm by ncb1397 »