Maven Mars
Ballistic capture could be used to Mars at a lower cost than current techniques. How does it work, and what are the drawbacks?

Excerpt from techtimes.com

Ballistic capture is a navigational technique utilized by spacecraft, and has been successfully utilized to coast into orbit around . Now, new research shows the same process may be used in flights to Mars, making trips to the Red Planet easier and less expensive.

Costs to fly to Mars can exceed hundreds of millions of dollars, and a large portion of that cost is directly related to arrival procedures once the vehicle reaches its destination. Spacecraft are usually traveling tens of thousands of miles per hour when they encounter the Martian . Entering orbit around Mars means firing retro-rockets, powered by fuel from Earth, in a process called a Hohmann transfer. Any extra weight aboard rockets means additional fuel must be expended, adding to mission costs. Risks are also in this type of operation, as spacecraft could veer off-, or go racing straight its .

Ballistic capture could be used in the place of Hohmann transfer, researchers found, although there is a price to pay for the fuel savings.

Ballistic capture involves placing a spacecraft into the same orbit as the target, a little ahead of the body, traveling slower than its destination. As the or Mars “catches up” to the vehicle, the spacecraft is captured by the body, entering orbit around its target. Reaching Mars or the still as much fuel as normal, but the need for braking is greatly reduced.

Ballistic capture and its possible utilization in future Mars missions was detailed in the Celestial Mechanics and Dynamical Astronomy