SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/aero-mars-window-25-months

About how often does a minimum-energy launch chance to Mars come around?

About every 25 months, when Earth and Mars line up right.

Start playing free

  1. Every month
  2. About every 25 months ✔
  3. About every 10 years

Why: To use the low-energy path, Mars has to be in the right spot when the spacecraft arrives. Earth and Mars return to that lineup only about every 25 months, so Mars missions launch in bunches.

Huh, didn't know that: Missing a Mars window means waiting about two more years for the next one.

The dad joke
Why did the Mars rover wait so patiently? Its window only opens every two years.
Like this card?
Play the game

References

Answer: About every 25 months. To use the low-energy path, Mars has to be in the right spot when the spacecraft arrives. Earth and Mars return to that lineup only about every 25 months, so Mars missions launch in bunches.

  1. NASA Science, Basics of Space Flight, Chapter 4 science.nasa.gov/learn/basics-of-space-flight/chapter4-1
    The opportunity to launch a spacecraft on a minimum-energy transfer orbit to Mars occurs about every 25 months.
    Checked 2026-10-10.

Think this answer is wrong? Tap "Challenge this answer" on the card in the game and tell us why.

Test yourself in the game

Flying & DronesWhy does Mars look red?Flying & DronesIn ballistic flight, which force is assumed to be the only one acting on the object?Flying & DronesWhat is an interplanetary Hohmann transfer known for?

That's stuff everyone should know.