1. It is also important in terms of planetary defense.

2. So if there is something planetary scientists want a closer look at, it can take a while to send the commands.

3. This is about much more than planetary definitions.

4. The quest to understand the interior of Mars has been a longstanding goal of planetary scientists for decades.

5. Miss that, and the mission would be grounded for two years before the right planetary alignment returned.

6. In this way we expect to identify clusters of rocks that could give rise to common impact events on both planetary bodies.