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Mars launch windows

Missions to Mars leave about every 26 months, when Earth and Mars line up. In the late 2026 Launch windowA launch window is the stretch of time, about every 26 months, when Earth and Mars line up so a spacecraft can reach Mars using the least fuel.More in the glossary, the lowest-energy day to leave is Oct 31, 2026, NASA calculates. The next window comes in late 2028.

Updated Sources (17)

When is the next Mars launch window?

Late 2026: NASA calculates that the lowest-energy day to leave is Oct 31, 2026. On that path a spacecraft reaches Mars on Aug 19, 2027, 292 days later. A faster path leaves on Nov 14, 2026 and arrives on Aug 9, 2027.[3]

A window has no single official start and end date. Each mission picks its own launch period around these days, and depending on the mission it lasts from a few minutes to a few weeks.[1] These are the missions planned for this window.[7][8][14]

Oct 20261919:41 UTCMMX launches to PhobosJAXA · H3 flight 10 · Oct 20, 04:41:03 JST

Japan’s mission to the Martian moons, bringing samples of Phobos back to Earth. JAXA has reserved backup launch days through Nov 7.

MMX mission
MonthNov 2026ESCAPADE leaves for MarsNASA · twin orbiters

In space since November 2025. NASA plans an Earth flyby in November 2026 that slings the pair toward Mars, arriving in September 2027.

ESCAPADE mission
Target2028No Starship this timeSpaceX

SpaceX’s Mars page says Starship cargo flights to Mars start no earlier than 2028.

Starship tracker

When are the next Mars launch windows?

Upcoming Mars launch windows: NASA’s lowest-energy day to leave in each, the trip it starts, and the missions planned for each
WindowLowest-energy day to leave (NASA)Planned missions
Late 2026this windowLonger path: arrive Aug 19, 2027 (292 days)Faster path: leave Nov 14, arrive Aug 9, 2027
MMXLaunch Oct 19 (UTC)JAXAESCAPADELeaves Nov 2026NASA · twin orbiters
Late 2028in about 2.1 yearsLonger path: arrive Oct 16, 2029 (318 days)Faster path: leave Dec 10, arrive Jul 20, 2029
Rosalind FranklinLate 2028ESA rover, on a NASA-provided launchSR-1 FreedomLate 2028NASAAeolus2028NASA instruments on a Relativity Space orbiterTianwen-3Around 2028China (CNSA)Starship cargoNo earlier than 2028SpaceX
Early 2031in about 4.4 yearsLonger path: arrive Jan 9, 2032 (320 days)Faster path: leave Jan 28, arrive Aug 6, 2031
None announced yet
Early 2033in about 6.6 yearsLonger path: arrive Jan 27, 2034 (274 days)Faster path: leave Apr 6, arrive Oct 1, 2033
None announced yet
Early 2035in about 8.5 yearsFaster path: arrive Nov 3, 2035 (196 days)Longer path: leave Jun 12, arrive Jul 28, 2036
None announced yet

Lowest-energy days from NASA Glenn’s mission design handbook, which works out every window from 2026 to 2045.[3] A mission is listed only where its agency or company has said which window it’s aiming for: ESA and NASA for Rosalind Franklin,[9][10] NASA for SR-1 Freedom[11] and Aeolus,[12] C17SA for Tianwen-3[17][13] and SpaceX for Starship.[14] A dashed tag is a company target.

Some windows cost less fuel than others, because the planets’ orbits are neither circles nor in quite the same plane. Of the windows from 2026 to 2045, NASA’s handbook finds that 2033 needs the least energy to leave Earth.[3]

Why do Mars launch windows come every 26 months?

Because Earth laps Mars about once every 26 months. Earth goes around the Sun faster than Mars, on the inside track. About once every 26 months the two line up for the most energy-efficient trip, NASA says.[2] The exact gap, called the synodic period, is 779.94 days, or about 25.6 months, so some NASA pages round it to 25 months instead.[5][15]

365.256 daysEarth’s year
686.980 daysMars’s year
779.94 daysbetween line-ups: the gap between launch windows

Sidereal orbit periods and the synodic period from NASA’s planetary fact sheets.[5][6]

What is a Hohmann transfer orbit?

The lowest-energy path from one orbit to another: half an ellipse around the Sun that touches Earth’s orbit at one end and Mars’s at the other.[15] On this textbook Transfer orbitA transfer orbit is the path a spacecraft coasts along around the Sun from Earth’s orbit to Mars’s, timed so that it and Mars arrive at the same place at the same time.More in the glossary, the trip to Mars takes about 259 days.[1]

NASA JPL works out the launch angle like this. The ellipse’s full orbit would take about 517 days, so the trip, half of it, takes about 259. In 259 days Mars moves about 136° around the Sun. To be there when the spacecraft arrives, 180° from where it left Earth, Mars must start about 44° ahead of Earth. That angle is the Phase angleHere, the phase angle is how far ahead of Earth Mars sits in its orbit, seen from the Sun; trips to Mars work best when it is about 44°.More in the glossary.[1]

The 44° rule treats the orbits as circles in one plane, which JPL says isn’t true but gives a fairly accurate answer.[1] NASA’s detailed calculations, which use the real orbits, land a few weeks away from it.[3] In this window Mars reaches 44° on about Dec 5, 2026, 35 days after NASA’s lowest-energy day. The dial at the top of this page tracks that angle live.

  1. Earth at launch. The spacecraft leaves here.
  2. Mars at launch, about 44° ahead of Earth.
  3. Mars at arrival, about 259 days later, on the far side of the Sun.
  4. Earth at arrival. It has moved on, too.

Orbits to scale; the path is illustrative. Scroll to fly it (the rocket stays still if you’ve asked for less motion).

How long real missions took

How we calculate this

Method and precision

The dial uses NASA JPL’s approximate orbital elements, the same ones behind our live distance to Mars, and redraws in your browser every minute.[4] The same engine finds the 44° days: Dec 5, 2026; Jan 7, 2029; Feb 10, 2031; Mar 19, 2033; May 10, 2035. The lowest-energy days in the table are NASA’s published calculations, not ours.[3] The page rebuilds daily, and “this window” moves on 30 days after its last lowest-energy day.

Questions

When is the next Mars launch window?

Late 2026. NASA calculates the lowest-energy day to leave as Oct 31, 2026. The window after that comes in late 2028, with its lowest-energy day on Dec 2, 2028.

What is a Mars transfer window?

Another name for a launch window: the weeks when a spacecraft can leave Earth on a Transfer orbitA transfer orbit is the path a spacecraft coasts along around the Sun from Earth’s orbit to Mars’s, timed so that it and Mars arrive at the same place at the same time.More in the glossary that meets Mars when it arrives, using the least fuel. It comes round about every 26 months.

Why do Mars launches happen every 26 months?

Because that’s how often Earth and Mars line up. Earth laps Mars every 779.94 days, about 25.6 months, and only near one point in each lap is a low-energy trip possible.

What is a Hohmann transfer?

The lowest-energy path between two orbits: half an ellipse around the Sun that touches both. From Earth to Mars it takes about 259 days, NASA JPL calculates.

How long does a launch window last?

From a few minutes to a few weeks, depending on the mission, NASA JPL says. NASA set Perseverance’s 2020 launch period for Jul 20 to Aug 11, and it launched on Jul 30.

Is SpaceX sending Starship to Mars in 2026?

No. SpaceX’s Mars page says Starship cargo flights to Mars start no earlier than 2028.

Sources

  1. NASA JPL Education — Let’s Go to Mars! Calculating Launch WindowsPrimary · checked Oct 4, 2026
  2. NASA Science — Mars Mission TimelinePrimary · checked Oct 4, 2026
  3. NASA Glenn Research Center — Interplanetary Mission Design Handbook: Earth-to-Mars Mission Opportunities 2026 to 2045 (NASA/TM-2010-216764)Primary · checked Oct 4, 2026
  4. NASA JPL Solar System Dynamics — Approximate Positions of the PlanetsPrimary · checked Oct 4, 2026
  5. NASA NSSDCA — Mars Fact SheetPrimary · checked Oct 4, 2026
  6. NASA NSSDCA — Earth Fact SheetPrimary · checked Oct 4, 2026
  7. JAXA — Launch schedule of the Martian Moons eXploration (MMX) spacecraft aboard H3 Launch Vehicle flight No.10 (H3 F10)Primary · checked Oct 4, 2026
  8. NASA — NASA, Blue Origin Launch Two Spacecraft to Study Mars, Solar WindPrimary · checked Oct 4, 2026
  9. ESA Exploration Science — ExoMars Rosalind Franklin (RFM)Primary · checked Oct 4, 2026
  10. NASA Science — NASA Begins Implementation for ESA’s Rosalind Franklin Mission to MarsPrimary · checked Oct 4, 2026
  11. NASA — Space Reactor-1 FreedomPrimary · checked Oct 4, 2026
  12. NASA — NASA Announces Public-Private Partnership to Advance Mars SciencePrimary · checked Oct 4, 2026
  13. Xinhua — China unveils international partners for Tianwen-3 Mars missionSecondary · checked Oct 4, 2026
  14. SpaceX — Mars & BeyondPrimary · checked Oct 4, 2026
  15. NASA Science — Basics of Space Flight, Chapter 4: TrajectoriesPrimary · checked Oct 4, 2026
  16. NASA JPL — Mars 2020 Perseverance Launch Press Kit: Mission OverviewPrimary · checked Oct 4, 2026
  17. China National Space Administration (CNSA) — China celebrates Space Day with a sneak peek at Tianwen 3's tech (Apr 24, 2026, from China Daily)Primary · checked Oct 6, 2026