NASA Mars rover: key questions about perseverance


Perseverance RoverImage copyright
NASA / JPL-Caltech

On July 20, NASA will have its first opportunity to launch the Perseverance rover to Mars. Here, we answer some common questions about the mission.

What will the rover do?

The Perseverance rover will land on Mars to look for signs of past microbial life, if it ever existed. It will be the first NASA mission to directly search for these “biological signatures” since Viking missions in the 1970s.

The rover will collect rock and soil samples, enclose them in tubes, and leave them on the planet’s surface to return to Earth at a future date. Perseverance will also study Martian geology and test a way for future astronauts to produce breathing oxygen and fuel from CO2 in the atmosphere.

Additionally, a drone-like helicopter will be deployed to demonstrate the first powered flight on Mars. Perseverance will explore the Jezero crater on Mars for at least one Martian year (approximately 687 Earth days).

How does it get to Mars?

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NASA / C. MANGANO

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The rover is encapsulated within an aerosol shell, consisting of a back shell and heat shield

The one-ton car-sized rover is slated to launch from Cape Canaveral Air Force Station in Florida on an Atlas 5 rocket between July 20 and August 11, 2020. Perseverance travels to Mars enclosed in a protective layer consisting of two parts: a conical back shell and a curved heat shield.

The aeroshell is connected to a cruise stage that fires thrusters to keep the spacecraft on course, ensuring it reaches Mars in the right place for landing. Perseverance will make its seven-minute descent to the Martian surface on February 18, 2021.

The relative positions of Earth and Mars mean that launch opportunities arise only every 26 months. If Perseverance did not launch to Mars this summer, the mission would have to wait until September 2022 to try again.

Technical Specifications: Perseverance Rover

  • Length: 3m (10ft)
  • Width: 2.7 m (9 ft)
  • Height: 2.2m (7ft)
  • Weight: 1,025 kg (2,260 lb)
  • Power supply: Multi-mission radioisotope thermoelectric generator (MMRTG). Converts heat from radioactive decay of plutonium to electricity.

How does perseverance land?

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NASA / JPL-Caltech

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Work: The overhead crane maneuver is designed to safely lower the vehicle to the ground

As the spacecraft passes through the Martian atmosphere, its heat shield will have to withstand temperatures of up to 2,100C (3,800F). When it is about 11 km (7 miles) from the ground, the spacecraft will deploy a parachute, slowing down the heaviest payload in the history of Mars exploration from a speed of Mach 1.7 (2,099 km / h; 1,304 mph) ) at approximately 320 km / h (200 mph).

Subsequently, the heat shield moves away from the rear cover and, for a short time, the rover, which is connected to a descent stage, falls freely to the ground.

Eight retro-rockets in the descent stage then fire, allowing the “sky crane” maneuver to be performed. Perseverance is lowered slowly with three nylon strings and an “umbilical cord”. When the rover’s wheels touch the ground, the ties are cut and the descent stage flies a safe distance.

Where on Mars will you be exploring?

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NASA / JPL-Caltech / MSSS / JHU-APL / ESA

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Jezero Crater on Mars – the rover’s landing ellipse is marked by the black circle

The rover’s target is an impact depression 30 miles (49 km) wide just north of the equator of Mars. Scientists believe that more than 3.5 billion years ago, river channels spilled onto the wall of the Jezero crater to form a lake.

The large bowl is also home to one of the best-preserved Martian examples of a delta, a sedimentary structure that forms when rivers enter open bodies of water and deposit rocks, sand, and potentially layered organic carbon.

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NASA / JPL / JHUAPL / MSSS / BROWN UNIVERSITY

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The Jezero Delta is one of the best preserved examples on Mars

Microbes could have lived in the crater when there was water there. Jezero maintains a record of important geological processes, such as the impact crater and volcanism, as well as the action of water. Studying its rocks will shed light on how the planet evolved over time.

How does the rover look for signs of past lives?

The Jezero fan-shaped delta is one of the main targets in the search for signs of past lives. Scientists also see carbonate minerals deposited around the crater shoreline like the ring in a bathtub. When carbonates rush out of the water, they can trap things that are in it, including evidence of life.

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Science Photo Library

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Stromatolites in Shark Bay, Australia

“We will look for biological signatures: patterns, textures, or substances that require the influence of life to form,” says project associate scientist Katie Stack Morgan.

We don’t know what Martian biosignatures would look like, but ancient Earth could provide clues. A record of our planet’s early life can be found in stromatolites, rocks originally formed by the growth of layer after layer of bacteria. If similar structures exist on Mars, scientists could combine measurements from different instruments to assess the probability of a biological origin.

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Media captionDrive with NASA’s next Mars rover through Jezero crater

Why do scientists think there might have been life on Mars?

Today, Mars is cold and dry, with a thin atmosphere that exposes the surface to damaging levels of cosmic radiation. But billions of years ago, the planet appears to have been wetter, with a thicker atmosphere. Multiple lines of evidence, such as the presence of shales and sedimentary bands, show that liquid water was once on the surface.

This is important because water is an essential ingredient for all life on Earth. Curiosity also found organic molecules preserved in sedimentary rocks three billion years old. While tempting, it’s unclear whether these organic compounds retain a record of ancient life, were their food, or have nothing to do with biological processes.

What instruments does the rover carry?

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NASA / JPL-Caltech

Perseverance is carrying an advanced payload of scientific instruments to gather information on Mars geology, atmosphere, environmental conditions, and possible biological signatures:

  • Mastcam-Z: An advanced camera system to help study surface minerals.

  • MEDA: A set of Spanish-made sensors to measure temperature, wind speed and direction, pressure, humidity and dust.

  • MOXIE: Experiment to demonstrate how astronauts can produce oxygen from Martian CO2 to breathe and fuel

  • PIXL: It has an X-ray spectrometer to identify chemical elements and a camera that takes close-up images of rock and soil textures.

  • RIMFAX: A Norwegian-built ground penetrating radar that will map geology below the surface at centimeter scales

  • SHERLOC: It will use spectrometers, a laser and a camera to search for organic compounds and minerals altered by water.

  • SuperCam: will examine rocks and earth with a camera, laser and spectrometers to look for organic compounds

Why fly a helicopter on Mars?

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NASA / JPL-Caltech

Wit is a 1.8 kg (4 lb) helicopter that will travel to Mars connected to the belly of perseverance. NASA wants to demonstrate a powered flight in the thin atmosphere of Mars. The red planet’s gravity is lower (about a third of that of Earth), but its atmosphere is only 1% of Earth’s density. This makes it more difficult to generate the lift needed to lift off the ground.

Equipped with two counter-rotating blades, the autonomous helicopter can take color images with a 13-megapixel camera, the same type commonly found in smartphones. Rotorcraft could be a useful way to explore other worlds: flying vehicles travel faster than ground rovers and can reach areas that are inaccessible to wheeled vehicles.

How does this rover differ from curiosity?

Image copyright
NASA / Kim Shiflett

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Wheels have been redesigned to be more wear resistant.

Perseverance is very similar to its predecessor Curiosity in terms of overall design, but there are key differences. In addition to the new scientific payload, Perseverance has a larger “hand” or turret at the end of its robotic arm to hold a heavier tool set, including a core extraction drill.

The system designed to cache samples is also a new feature. Engineers have redesigned the rover’s wheels to be more wear resistant. Curiosity’s wheels suffered damage while driving on sharp, pointed rocks.

How does the rover store rocks and dirt?

The mobile’s sample caching system consists of three robotic elements. Most visible is the 2.1 m (7 ft) long five-link robotic arm, which is bolted to the chassis. A rotary hammer drill on the arm turret can cut intact cores from Martian rock. These cores, about the size of a piece of chalk, fit into a sample tube. The robot’s main arm places the filled tube into a mechanism at the front of the mobile called a drill carousel.

Reminiscent of a slide projector from the 1960s, this mechanism moves the tube inside the mobile where a smaller sample handling arm of 0.5 m (1.6 ft) is located (also called Tyrant saurian Rex arm) grabs it. An image is taken before hermetically sealing the tube and placing it on a storage shelf. It is driven by the scout vehicle until the team finds a suitable place to drop it off.

How will Martian samples be delivered to Earth?

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ESA / ATG Medialab

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Artwork: The plan calls for a fetch rover to be dispatched to collect the sample containers

For decades, scientists have wanted to deliver samples of Martian rock and earth to Earth for laboratory study. Here, scientists could investigate the samples with instruments too large and complex to send to Mars. By leaving rock and soil samples on the surface in sealed tubes, perseverance will lay the foundation for that to happen.

As part of the program known as the Mars Sample Return, a separate mission will be sent to land on Mars to collect the tubes using a fetch rover. Then a robotic arm will transfer the tubes from the scout vehicle to a rocket called the Mars Ascent Vehicle (MAV). The ascent vehicle drops the samples into Martian orbit, where they are captured by an orbiter. This orbiter will then deliver the sample containers to Earth, possibly by 2031.

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