NASA’s Perseverance rover left the first of at least 10 sample tubes on the surface of Mars for a future sample return mission to Earth.
While Perseverance is carrying most of the samples, the tubes left on the ground will remain as a backup in case the rover is damaged or stuck before the retrieval mission. After dropping the first sample off on Dec. 21, 2022, the rover will spend the next few weeks leaving the first batch of samples at a location called Three Forks.
“Seeing our first sample on the ground is a great capstone to our prime mission period, which ends on January 6,” said Rick Welch, Perseverance’s deputy project manager at NASA’s Jet Propulsion Laboratory, in a statement. “It’s a nice alignment that, just as we’re starting our cache, we’re also closing this first chapter of the mission.”
The cache includes samples collected by the rover from across Jezero Crater. The 50 kilometre-wide crater includes an ancient river delta that flowed into a lake billions of years ago. Deltas on Earth are rich sources of microbial life. Organisms were found embedded in the rocks.
Perseverance has been on Mars for nearly two Earth years, or nearly one Martian year (it will reach a full year on Feb. 18, 2023). Since arriving on Mars, the rover collected 16 rock samples and one atmospheric sample in titanium tubes roughly the size of test tubes. At each site, Perseverance collects a duplicate sample. The rover has 43 containers.
If the current schedule holds, a Sample Retrieval Lander carrying a rocket and two helicopter drones will head to Mars in 2027. Perseverance will deliver the samples stored in its belly, while the drones will gather the cached samples.
The samples will be loaded onto the rocket and launched towards a spacecraft orbiting Mars. The spacecraft will return to Earth and the samples will land in the Utah desert sometime in 2033.
The drones are designed to gather the samples left on the ground individually, so the tubes will be spaced apart instead of clumped in a pile.
“Up to now, Mars missions required just one good landing zone; we need 11,” said Richard Cook, Mars Sample Return program manager at JPL, in a Dec. 16, 2022, statement.
“The first one is for the Sample Retrieval Lander, but then we need 10 more in the vicinity for our Sample Recovery Helicopters to perform takeoffs and landings, and driving too.”
Once Perseverance’s prime mission ends on Jan. 6, 2023, Perseverance will focus on preparing the depot at Three Forks. The rover will then head to the top of the delta. It will spend eight months searching for boulders that were carried from elsewhere on Mars by the ancient river that formed the delta.
“The Delta Top Campaign is our opportunity to get a glimpse at the geological process beyond the walls of Jezero Crater,” said JPL’s Katie Stack Morgan, deputy project scientist for Perseverance, in a Dec. 16, 2022, statement.
“Billions of years ago a raging river carried debris and boulders from miles beyond the walls of Jezero. We are going to explore these ancient river deposits and obtain samples from their long-traveled boulders and rocks.”