Earth and Mars align favorably only every 26 months . This alignment, known as "opposition," minimizes the fuel needed for the roughly 300-million-mile trip.
Using current chemical propulsion, the one-way journey typically takes 7 to 9 months . 3. The Martian Environment Challenges
Testing technologies for landing large payloads and surviving the harsh environment. 2. Launch Logistics
Determining if Mars ever supported microbial life.
Mars is a hostile environment that dictates how equipment and habitats are designed: Mars - NASA Science
