At that time, NASA decided to test the separation of the rover from its descent stage by firing the pyrotechnic devices that held the two together, and them, using a crane, to lift the descent stage. The two pieces of the puzzle will remain detached from one another until next spring, when the final assembly will be made.
The Mars 2020 mission will depart next July and has a planned arrival date for February 2021. And the success of the mission relies solely on the ability of the spacecraft to separate from the descent stage and land safely.
Using a technology called Terrain-Relative Navigation (TRN) with Lander Vision System (LVS), the on-board computers will determine in advance if a landing site is safe for the rover. If it’s not, for the first time in the history of space exploration, the spacecraft will be steered out of harm’s way.
"There had been Moon landings with robotic spacecraft before Apollo 11," said Al Chen, entry, descent and landing lead for NASA's Mars 2020 mission.
"But never before had a spacecraft on a descent toward its surface changed its trajectory to maneuver out of harm's way. What we needed was a Neil Armstrong for Mars. What we came up with was Terrain-Relative Navigation."
You can learn more about the 2020 mission to Mars at this link.