4 ms·

The thing is, if they miss the date by mere months, they will have to wait 2 years for the next launch window.

• iandanforth 10y ago
  More info for people curious about this. The best time to launch is during "Earth Mars opposition" and the next window is in Jul 2018. After that there is a 26 month wait before the next optimal (from a fuel perspective) time.
  • ohitsdom 10y ago
    I thought the biggest concern about launch window was journey time? And that would only matter for a crewed mission. I didn't think fuel mattered because it would probably be close for either mission profile- burn to get up to speed, shutdown and coast for months, then any orbit corrections and slowdowns as the Mars approach nears. It's not like the engine is burning for the whole trip, and they'll be using solar for internal instruments. Or am I misunderstanding?
    • zardo 10y ago
      You are, the total energy required for a transfer varies considerably depending on the phasing of the planets. This is mars->Earth, but you get the idea. http://www.projectrho.com/public_html/rocket/images/mission/Mars2103PorkChop.png http://www.projectrho.com/public_html/rocket/images/mission/...
  • aaron-santos 10y ago
    Do you have more info on Earth Mars opposition launch windows? It struck me as odd because a western-quadrature[1] alignment is a decent approximation of a launch window when using a Hohmann transfer from an inner to outer planet in KSP. The maven orbital path[2] seems to confirm this. [1] https://en.wikipedia.org/wiki/Quadrature_(astronomy)#/media/File:Quadrature_(astronomy).png https://en.wikipedia.org/wiki/Quadrature_(astronomy)#/media/... [2] http://mars.nasa.gov/images/MAVEN_orbital_path_rev-br2.jpg http://mars.nasa.gov/images/MAVEN_orbital_path_rev-br2.jpg