NASA is still planning to launch its Mars 2020 rover next Summer, with an official launch window slated for some time in July. But before the American space agency can move forward with attaching its ambitious Mars-exploring mission to the top of a rocket, it must ensure that the integrated payload fits together correctly.
Image Credit: NASA/JPL-Caltech
The term NASA uses to describe this process is ‘stacking,’ and it is customary for space agency personnel to partake in this practice for missions of this scale. The term is particularly fitting because engineers at NASA’s Jet Propulsion Laboratory are sandwiching parts together like Legos to make sure all the holes line up and that the dimensions are within specifications.
"One of our main jobs is to make sure the rover and all the hardware that is required to get the rover from here on Earth to the surface of Mars fits inside the payload fairing of an Atlas V rocket, which gives us about 15 feet of width to work with," elucidated David Gruel, the ATLO manager for the Mars 2020 mission at JPL.
In a statement, NASA explains that the stacking process begins by placing the rocket-powered descent stage over the surrogate Mars 2020 rover and then covering the result with a back shell via crane. Afterward, the team installs the parachute nose cone, the cruise stage, and then the heat shield, all in that order.
Integrating everything into one piece is tedious work, and because of the sheer size of what the team is working with, at least a dozen NASA engineers and technicians work together to ensure everything goes smoothly. In addition to calling on the help of a crane, the team uses the Spacecraft Assembly Rotation Fixture to physically rotate the entire project and access those ‘hard to reach’ places.
"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," Gruel added. "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."
As you might have noticed, we said ‘surrogate’ Mars 2020 rover, and that’s because the real one is still being built and enduring testing. The surrogate acts as a placeholder, as its dimensions are identical to that of the true rover. Obviously, NASA will integrate the true Mars 2020 rover into the stack after completing it ahead of the launch.
In the meantime, NASA plans to test the stack by subjecting it to cryogenic and vibration testing, much like what it will experience when being rocketed into space and when traveling to Mars. This testing will ensure that everything holds together and that none of the bolts come loose from the vibrations.
It’d be an understatement to say that the Mars 2020 rover mission is coming together; in fact, it’s nearly ready for launch. We only wish we could say the same about the James Webb Space Telescope…