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The American space agency NASA's Mars explorer has begun dropping rock samples it collected on the planet's surface. A different spacecraft is to recover the samples at a future date and return them to Earth.

The Perseverance¹ explorer, or rover, landed on Mars in February 2021. It has been collecting rock, soil and atmospheric² samples at Mars' Jezero Crater³ area since September 2021.

NASA officials have said detailed⁴ study of the samples on Earth will be important to help scientists understand whether life ever existed on Mars.

NASA said Perseverance has collected 18 different samples. The space agency plans to pick up the collected materials during a Mars mission planned for 2028.

The joint⁵ mission with the European Space Agency would involve a lander spacecraft being sent to Mars along with a small rocket. The samples would be loaded onto the rocket to be transported to Earth. If the mission goes well, the samples could arrive on Earth in 2033.

The samples are kept inside a storage area inside the rover. They are kept inside air-tight titanium tubes to be protected from the severe conditions on Mars. Most of them will be kept inside a container on Perseverance until the return mission happens. But NASA decided⁶ to drop 10 of them on the planet's surface in case something goes wrong with the ones kept inside the rover.

NASA said the tubes dropped on the surface could be picked up by a helicopter-like vehicle and transported to the rocket to be brought to Earth. The space agency has already demonstrated that its Ingenuity⁷ helicopter can operate successfully on Mars.

Perseverance collected the samples with robotic equipment attached to the rover. The collection operations are led by NASA mission controllers on Earth. Perseverance has a drill attached to a robotic arm it uses to collect small, circular rock samples from beneath the surface.

NASA said in a statement the first sample container was dropped on the Mars surface by Perseverance on December 21. The agency plans to drop the remaining nine containers over the next two months.

Perseverance will be releasing the samples in an area of Jezero Crater known as "Three Forks." Scientists believe Jezero Crater contains the remains⁸ of an ancient river system. NASA considers the area a good place to find possible signs of microscopic⁹ life. Scientists believe if life ever existed on Mars, it would have been present 3 to 4 billion years ago, when water flowed on the planet.

Meenakshi Wadhwa is a scientist from Arizona State University who helps lead the scientific team of the Mars Sample Return program. She said the samples collected so far represent a good mix of different kinds of rock and soil found in the area being explored by Perseverance. The rover still has more than 20 empty containers that can be used in the collection mission.

NASA officials said the operation to drop samples on the surface of Mars has been complex. This is because the chosen sites must be reachable by both flying and driving vehicles.

Richard Cook is the Mars Sample Return program manager at NASA's Jet Propulsion Laboratory in Southern California.

He said once the 10 drop areas were identified, the team then had to map out exactly how the rover could effectively get to those places to deploy¹⁰ the samples. "You can't simply drop them in a big pile because the recovery helicopters are designed to interact with only one tube at a time."

The team decided to create an "area of operation" stretching about 5.5 meters for each dropping point. The tubes are to be dropped about five to 15 meters apart from one another.

NASA said mission controllers will be examining numerous images captured by the rover to assist them in deciding where to drop the samples. The images will also help the team identify exactly where the samples are in case they are covered in sand or dust before they are collected.

Words in This Story

sample – n. a small amount of something that gives you information about the thing it was taken from

mission – n. an important project or trip, especially involving space travel

drill – n. a tool or machine used for making holes in a hard substance

air-tight –adj. secured so that air cannot enter

pile – n. a collection of a number of objects placed on top of each other