Travel time to Mars depends on the mission design and planetary alignment. Here are the most commonly cited ranges and what they mean:

• Typical crewed-Hohmann-transfer missions: about 7 to 9 months to reach Mars, with most estimates clustering around roughly seven months for the transit leg. This is the conventional figure used in NASA planning and many mission studies. [sources: general NASA mission planning discussions and historical estimates]
• Alternative trajectories: faster short-cut trajectories are sometimes discussed, potentially reducing transit to around 6 months for specific propulsion concepts, but these often come with higher propulsion demands, steering challenges, and higher risk. [sources: propulsion concept discussions and space-access analyses]
• Historical robotic missions: spacecraft that traveled to Mars have taken anywhere from about 4 months to over 9 months depending on launch date, alignment, and trajectory design; note these are non-human missions and don’t include landing or surface transit time. [sources: historical mission data]

Important clarifications:

• “How long to get to Mars” usually refers to the interplanetary cruise phase; it does not include the time to enter Mars orbit or to land, which adds additional time and complex braking/post-landing phases.
• The minimum energy transfer (a slower, efficient route) is typically longer in duration, while higher-energy, faster trajectories demand more powerful propulsion and precise navigation.

If you’d like, I can tailor this to a specific propulsion concept (chemical rockets, nuclear thermal, ion drives) or a particular mission profile (military/space agency crewed mission vs. hypothetical private-sector plan) and provide a more precise time window with the caveats.