WASHINGTON-NASA’s next Mars mission is slowly coming together in a “clean room” in California. Technicians at the agency’s Jet Propulsion Laboratory assembled the capsule that will keep the Mars 2020 rover secure for its wild ride to the Red Planet’s surface.

After leaving Earth next summer, Mars 2020 will spend about seven months flying towards the Red Planet before a spectacular entry at its destination, including a repeat of the famous “7 minutes of terror” sequence that brought NASA’s Curiosity rover to the planet’s surface in 2012. (The Mars 2020 rover and Curiosity have similar body frames, although they carry different instruments.) So, all the parts need to be secured in the Mars 2020’s entry capsule in a process called “stacking.”

“Stacking is an important milestone in mission development, because as good as our computer models are, we still need to put it together to show that the bolt holes line up and everything fits together,” David Gruel, assembly, test and launch operations manager for Mars 2020 at JPL, said in a statement.

“It is a great feeling for the entire project when we see the stack sitting there waiting to go for the next part of its journey, which will eventually lead to a launch pad at the Cape Canaveral in July of next year.” The stacking process includes both the real rover and a surrogate rover; the latter is being tested to make sure everything fits properly before using the real flight hardware.

In the most recent batch of checks, technicians placed the rocket-powered descent stage on top of the surrogate rover. After confirming that the holes in the stage and surrogate lined up, they performed a careful check before lowering the “back shell” — part of what protects the rover as it enters the Martian atmosphere — and checking the alignment. Next, the team tested the fit of a parachute nose cone. This important piece will protect the parachute as the Mars 2020 shell slams into the atmosphere; once the fiery entry is over, Mars 2020 can safely deploy the parachute to slow its descent.