New Mars Forums

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Conjunction & Opposition Launch Windows to Mars

I want to find out when the launch windows to mars for both conjunction and opposition class missions occur over the next ~50 years or so.

Has anyone here worked it out?

---

- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

cIclops

Member

Registered: 2005-06-16

Posts: 3,230

Re: Conjunction & Opposition Launch Windows to Mars

This looks like a good paper on the subject (PDF), it addresses the conjunction class missions rather than the short stay opposition class ones.

data file for earth - mars conjuntion trajectories

---

[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Conjunction & Opposition Launch Windows to Mars

Thanks cIclops.

What I intend to find is how far the launch window can be extended if given the option of earth departure at both conjunction and opposition.

The data on available launch windows for a conjunction class mission is excellent. Now I just need something similar for opposition class missions.

My intention is to graphically represent when launch opportunities open and close through the years 2020 to 2040, perhaps by using green and red bands of colour in a linear progression.

---

- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

Michael Bloxham

Member

From: Auckland, New Zealand

Registered: 2002-03-31

Posts: 426

Re: Conjunction & Opposition Launch Windows to Mars

Just scouting through a few sites brought up by google, it seems as though launch windows for opposition class missions occur between those of conjunction class missions. I guess this would make sense as conjunction and opposition refer to the position of Mars in its orbit?

So the available launch windows might look like this:

2021 (opposition)
2022 (conjunction)
2023 (opposition)
2024 (conjunction)
2025 (opposition)
2026 (conjunction)

Can anyone confirm this?

---

- Mike,  Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,431

Re: Conjunction & Opposition Launch Windows to Mars

The chances of using both mission types opens up being able to make it to mars more often. We know that travel time is 6 to 9 months typical but when we make use of ion that all changes for cargo.

https://ntrs.nasa.gov/archive/nasa/casi … 001240.pdf
Trades Between Opposition and Conjunction Class Trajectories for Early Human Missions to Mars

Conjustion is making use of the travel time to lead and lag mars arrival and return.
Opposition is using a venus flyby for a short term stay on mars surface.

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,451

Re: Conjunction & Opposition Launch Windows to Mars

Opposition class missions carry a bit more risk to astronauts in cases of solar flare activity. All of the Mars Direct architecture utilizes Conjunction class launches.