NASA's next Mars rover will launch in 2020, and it's being built before our eyes - here's what the robot's birth has looked like

The Mars 2020 rover's design is based on that of Curiosity, which has been exploring the red planet since 2012. Curiosity discovered that Mars once had environments that could have supported microbial life. Mars 2020 will search for signs of that life.

Once completed, Mars 2020 will feature six wheels, a mast to raise cameras to human eye level, a robotic arm, three antennae, and seven impressive scientific instruments. All in all, the mission is set to cost NASA $2.1 billion.

The goal is as ambitious as the cost: NASA aims to determine whether life ever existed on Mars.

The mission is also expected to teach researchers much more about the planet's climate and geology — it will be the first to collect samples of rock and soil. Overall, the work is part of long-term preparations to send future human explorers to Mars.

Since NASA announced the start of the rover's assembly last year, the team has been fitting the pieces together step by step.

Last year, technicians painted the rover's chassis — basically its skeleton.

The rover is scheduled to explore Mars' windy, high-radiation surface for at least two years, so a proper covering will help the robot stay alive. The chassis got a very precise paint job before the technicians started attaching components: Three coats of paint for a thickness of between four- and six-thousandths of an inch.

Then in March, engineers installed an instrument that can convert carbon dioxide into oxygen. If it works, it could solve a big problem facing future human explorers.

One of the biggest obstacles to putting people on Mars is that the planet's air is very thin, so humans would have to bring their own oxygen or produce it on-site.

But the device that the new Mars rover will test out — called the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) — is designed to convert the abundant carbon dioxide on Mars into breathable oxygen. (About 95% of the red planet's atmosphere is CO2.)

If MOXIE is a success, it would offer a lighter, cheaper alternative to hauling oxygen tanks through space. Plus, the ability to covert carbon dioxide into oxygen could allow for the creation of rocket fuel for a return trip back to Earth.

MOXIE is the size of a car battery, but similar equipment for use on human missions would need to be 100 times larger. Even that would save precious space on a crewed flight to Mars, though, since MOXIE could hypothetically replace both oxygen tanks and three-quarters of the necessary propellant.

In April, Mars 2020 got an antenna that will enable it to communicate with Earth.

NASA will be able to steer this antenna to point directly at Earth. That way, the rover won't have to change location to receive and send data. In total, the rover will get three antennae to give NASA back-up options for staying in touch with its robot.

Later that month, technicians installed Mars 2020's heart: its motor.

The rover's motor control assembly (RMCA) gives it the ability to move: The tool manages motion of Mars 2020's wheels, arms, mast, drill, and the instruments that will handle Martian rock and soil samples.

Throughout the spring, helicopters tested out the rover's navigation system.

"What we needed was a Neil Armstrong for Mars," Al Chen, the entry, descent, and landing lead for the Mars 2020 mission, said in a press release. "What we came up with was Terrain-Relative Navigation."

This navigation system acts as an autopilot, monitoring the rover's location over the Martian terrain, calculating its trajectory, and changing course if things look too dangerous.

This will allow the rover to land safely in the 28-mile-wide Jezero Crater, which contains cliffs, sand dunes, and boulder fields. (Those obstacles made the crater too risky for previous missions to visit.) Researchers think this area's 3.6-billion-year-old geology could tell us a lot about the planet's history and perhaps offer signs of ancient microbial life.

For three weeks, NASA flew the navigation's vision component (the Lander Vision System) over the Mars-like terrain of Death Valley and the Mojave Desert. They tested the equivalent of 659 Mars landings, and the tool held up.

Then in May, two high-definition cameras were fit onto the rover's mast.

Mastcam Z is a 3D camera that can take high-definition photos and high-speed video. There are two on the rover's mast. These cameras will identify rocks and soil for the rover's other instruments to investigate or collect and stow. The cameras will also help scientists observe details in Martian rock and sediment.

"Mastcam-Z will be the first Mars color camera that can zoom, enabling 3D images at unprecedented resolution," Jim Bell, the Mastcam-Z team's principal investigator, said in a release.

Last month, construction really started ramping up. In early June, the team attached the mast to the rover's body.

As the rover travels to Mars, the mast will lay flat, stowed away in its deck. Upon landing, the rover's first order of business will be to hoist up the mast — and its various cameras and instruments — to a high perch over 7 feet above the ground.

In mid-June, the rover got its wheels and two titanium legs.

The rover will have six aluminum wheels, each with an individual motor and 48 cleats for traction. Thanks to additional steering motors on the two front and two rear wheels, the rover will be able to turn 360 degrees in place.

The rover's suspension system is designed to give each wheel a relatively constant, even weight. That helps prevent the robot from falling over — it can handle a tilt of up to 45 degrees.

The wheels currently on the rover are models. The team will replace them sometime next year.

The rover's robotic arm, which has five motors and five joints for optimal mobility, was installed on June 21.

The rover's 7-foot arm will operate as a human scientist's would, extracting and stashing rock cores, snapping microscopic photos, and analyzing the soil as as the rover trudges along the Martian landscape.

It hasn't yet gotten its hand, though: The turret (still to be installed) will hold and operate the sample-collecting instruments, including a drill and more high-definition cameras.

The rover's impressive SuperCam tool can identify the mineral, chemical, and atomic composition of a target the size of a pencil point up to 20 feet away. It was installed on June 25.

The SuperCam is the result of collaboration between engineers in the US, France, and Spain. The tool includes a camera, laser, and spectrometers that determine which elements are present in distant rock or soil by measuring how much light atoms absorb or reflect.

"It lets the Mars 2020 rover conduct its cutting-edge science from a distance," Soren Madsen, a project manager at the Jet Propulsion Laboratory, said in a press release.

On Mars, the SuperCam will collect data about how compounds in the Martian atmosphere interact with solar radiation, which could improve scientists' abilities to predict Martian weather. Along the way, it will also scan nearby rocks and soil for signs of ancient water or even microbial life.

What's more, the SuperCam will look for elements in Martian dust that might be harmful to future human explorers.

In the coming weeks and months, the team will fit even more parts onto the rover, including a tool that will test out pieces of spacesuit material.

A piece of a helmet and several fabrics will make the trip to Mars, where a tool called SHERLOC will monitor how these items react to Martian dust storms and the sun's radiation (which is 2.5 times stronger on Mars' surface than at the International Space Station). This could help NASA develop spacesuits for future human missions to the red planet.

The rover is also slated to get sensors that will provide daily weather reports and collect data on wind, dust, and radiation, as well as an instrument that can analyze the chemistry of tiny targets to test for traces of ancient life.

Monitoring Martian weather will help scientists learn more about the planet's dramatic seasonal changes. Accurate weather predictions will be essential if humans are to safely explore Mars.

The hunt for traces of ancient microbial life will also involve a tool that shoots X-ray beams at tiny target points. In five seconds, it can analyze the results to map the target's elemental makeup.

Yet another tool still to be added will penetrate a part of Mars that instrument has ever probed before: deep underground.

The instrument, called RIMFAX, will use radar to see geologic layers and features over 30 feet below the Martian surface. There's a lot of climate history down there — just think how much we've learned about Earth from analyzing its layers.

When RIMFAX sends down radar waves, they'll return as sonogram-like signals that reveal which materials lay below. The analysis could find buried layers of sediment, rock, ice, water, or saltwater.

The rover's sample-collection system, meanwhile, will carry 43 containers in which to store bits of rock or soil.

The rover will store the rock cores that it collects in its belly. Eventually, the robot will deposit those samples in a spot on Mars for a future mission to find and hopefully return to Earth.

You can watch the rest of Mars 2020's birth unfold via NASA's live broadcast of the engineers at work.

NASA has installed a camera to broadcast the Mars 2020 construction live at the Jet Propulsion Laboratory in Pasadena, California.

"You can watch engineers and technicians assemble and test the rover before it embarks next year on one of the most technologically challenging interplanetary missions ever designed," NASA said.

Tune in anytime to watch the $2.1 billion rover take shape before it launches in July 2020.