Why Mars Travel Time Varies

The distance between Earth and Mars is constantly changing, affecting spacecraft travel time.

Published on Feb. 9, 2026

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The travel time from Earth to Mars can vary significantly, from as little as 7-9 months to as long as 2 years. This is because Earth and Mars are constantly moving, so the distance between the two planets is not constant. Additionally, spacecraft don't travel in a straight line to Mars, but instead follow an elliptical Hohmann transfer orbit that requires the least amount of energy.

Why it matters

Understanding the factors that affect travel time to Mars is crucial for planning future crewed missions to the Red Planet. NASA's Orion spacecraft and Space Launch System rocket are being developed to carry astronauts to Mars, with the first crewed Artemis 2 mission around the Moon planned for 2026.

The details

Spacecraft from Earth don't travel in a straight line to Mars, but instead follow a Hohmann transfer orbit, an ellipse that allows the spacecraft to arrive at Mars using the least amount of energy. However, the distance between Earth and Mars is constantly changing as the two planets orbit the Sun, which can dramatically impact the travel time. Launches outside the optimal 26-month window can increase the journey to Mars from 7-9 months to as long as 2 years.

  • Earth and Mars are in their best position for interplanetary travel every 26 months.
  • NASA's Orion spacecraft and Space Launch System rocket are being developed for future crewed missions to Mars.
  • The first crewed Artemis 2 mission around the Moon is planned for March 2026.

The players

Orion spacecraft

NASA's spacecraft that will carry crew members to Mars, launched atop the powerful Space Launch System rocket.

Space Launch System (SLS) rocket

NASA's new heavy-lift rocket that will launch the Orion spacecraft on missions to the Moon and Mars, more powerful than the Saturn V rocket that carried astronauts to the Moon.

Artemis 1

NASA's uncrewed test flight of the Orion spacecraft and SLS rocket, which launched in 2022 and traveled around the Moon.

Artemis 2

NASA's planned first crewed mission of the Orion spacecraft and SLS rocket, scheduled to launch around the Moon in March 2026.

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What they’re saying

“I've read that the planned crewed Mars missions will take six months or two years to arrive. Which is it? Could a longer trip be due to the heavy payload? Our rovers took only eight to nine months to arrive.”

— Ronald Greene, Reader (astronomy.com)

“When it comes to a trip to the Red Planet, your mileage may vary — literally. Earth and Mars are constantly moving, but they don't stay a constant distance apart. Furthermore, spacecraft from Earth don't travel in a straight line to the Red Planet. Instead, astronauts leaving Earth would follow a path known as the Hohmann transfer orbit, an ellipse from where Earth is now to where Mars will be in the future. This orbit requires the least energy (and thus the least fuel) and allows the spacecraft to arrive within seven to nine months.”

— Nola Taylor Tillman, Freelance science journalist and Astronomy contributor (astronomy.com)

What’s next

NASA is planning to launch the crewed Artemis 2 mission around the Moon in March 2026, which will be a crucial step towards future crewed missions to Mars.

The takeaway

The travel time from Earth to Mars can vary significantly due to the constantly changing distance between the two planets and the need for spacecraft to follow an elliptical Hohmann transfer orbit. Understanding these factors is crucial for planning future crewed missions to Mars, which NASA is working towards with the development of the Orion spacecraft and Space Launch System rocket.