Mars 2020 rover
Development of Mars 2020 remains on schedule despite uncertainty about when future phases of the overall Mars sample return effort will launch. Credit: NASA/JPL-Caltech

WASHINGTON — NASA’s Mars 2020 mission has passed its final review ahead of a July 30 launch that will kick off an ambitious effort to return samples of the red planet to Earth.

NASA announced July 27 that Mars 2020 completed its launch readiness review, confirming that the spacecraft and its Atlas 5 launch vehicle are ready for launch. The Atlas 5 will roll out to the pad at Cape Canaveral Air Force Station in Florida July 28, with launch scheduled for 7:50 a.m. Eastern July 30.

Weather is forecast to be favorable for the launch. At a July 27 briefing at the Kennedy Space Center, Jessica Williams, launch weather officer at the U.S. Space Force’s 45th Space Wing, said there was an 80% chance of acceptable weather for the July 30 launch attempt, improving to 90% if the launch slips one day.

Nearly an hour after the United Launch Alliance Atlas 5 541 lifts off, its Centaur upper stage will release the Mars 2020 spacecraft, having placed it on a Mars-bound trajectory. The spacecraft will arrive at Mars on Feb. 18, 2021, and attempt a landing in Jezero Crater, a large crater on the planet that once was home to a river delta.

The Mars 2020 rover, named Perseverance, is based on the Curiosity rover that has been on Mars for nearly eight years, but with a number of changes. “It’s clearly a more sophisticated vehicle,” Matt Wallace, Mars 2020 deputy program manager, said of Perseverance. “We’re carrying about 50% more surface payload than Curiosity did, and that was by far the most complex thing we had ever done up until that time.”

A major driver of that increased complexity is the rover’s mission to cache samples for later return to Earth. “The sampling and caching system is a robotically complex system,” said Jennifer Trosper, another deputy project manager for the mission. Besides its complexity, she noted it has to be “super clean” to avoid any terrestrial contamination of the samples it collects. “That has been the hardest thing to develop on the Perseverance rover.”

Those samples will be returned on a pair of missions, an orbiter and lander, projected to launch in 2026 in a cooperative effort between NASA and the European Space Agency. Both missions are still in their earliest phases of development, with no cost estimates yet released. Mars 2020 cost NASA $2.4 billion, with another $300 million budgeted for the rover’s first Martian year of operations.

Another factor in the mission’s complexity is the addition of Ingenuity, a small helicopter that will be carried to Mars with Perseverance. After landing, Perseverance will release Ingenuity, which will then perform a series of flight tests to demonstrate the ability for powered, controlled flight in the planet’s thin atmosphere.

Ingenuity was added to the mission relatively late in its development, and Wallace said that it required a “little bit of a magic trick” to accommodate it. “It’s a very, very unusual payload,” he said. “Our team was oversubscribed with engineering challenges.”

JPL engineers, with support from Lockheed Martin, were able to accommodate Ingenuity by attaching it to the rover’s underside. “We’ll be ready to go when it’s time to fly the helicopter on Mars, but it wasn’t easy,” he said.

A further complication for Mars 2020 was the coronavirus pandemic that hit as the mission was preparing the spacecraft for launch. “Nothing prepared us for what we had to deal with in the middle of March as the pandemic struck,” Wallace said. “We’re working with very limited schedule.” If Mars 2020 doesn’t launch by the middle of August, NASA will have to wait for more than two years for the next launch window.

The pandemic also affected those handling the launch itself. “I would never have thought that a launch director would be working from home,” said Omar Baez, the NASA launch director for Mars 2020.

He noted that, in contrast to launch readiness reviews for previous missions that were often standing room only, the review for Mars 2020 has fewer people in the room, with those in attendance wearing masks. “There’s a challenge and a penalty that goes with doing those things,” he said. “I’ve seen the team react and overcome all that, and it makes me very proud.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...