History of Mars rovers

A planetary rover, or rover in English, is a moving device used to explore the moons and planets of the Solar System. This buzzy name actually refers at the moment to the exploration of one moon and one planet — Mars. Only in these extraterrestrial locations operated and still operate rovers. Each rover is equipped with an array of sensors and cameras. Some can also take soil samples and give them a preliminary analysis. The rovers are mobile, extraterrestrial laboratories. Their history dates back to 1969, the same year that the Apollo 11 crew landed on the moon.

Lunar rover. The first was Lunochod

The first robot to land on the Moon was the Soviet Lunochod, now referred to as “rover zero”. Unfortunately, it didn’t make it because it was destroyed during a failed launch that occurred on February 19, 1969.

Before rovers, humans reached the Moon. However, as early as November 1970, Lunochod 1 arrived on the Silver Globe, which for 30 years held the title of the longest operating planetary rover. It worked for as long as 11 months, which is a very good result. Especially if we take into account that the ubiquitous dust on the Moon changes under the influence of cosmic radiation into plasma, which has a destructive effect on mechanical parts.

The Lunochod was a relatively large and very massive structure. It weighed over 750 kilograms and resembled a log on metal wheels. However, it was clearly a breakthrough in the history of robotic space exploration. Its mission was supposed to last only three days; it lasted 11 months. After landing in the so-called Sea of Rain, it traveled less than 200 meters. However, this was enough to send 26 images to Earth and analyze samples of lunar regolith. Its next version — Lunochod 2 — traveled as much as 39 kilometers on the Moon.

Another type of lunar rover was the LRV, or Lunar Roving Vehicle used during the last three missions of the Apollo program to transport equipment and the astronauts themselves. This rover was not a mobile laboratory, but a functioning four-wheeled buggy-type vehicle. During its last mission — Apollo 17 — it broke the speed record on the Moon, reaching 18 km / h. What is important, behind the design of the rover was an engineer Mieczysław Bekker. He was a graduate of the Warsaw University of Technology and a soldier, who in 1942 accepted the proposal of the Canadians and moved to Ottawa to develop armoured vehicles.

Mars rover — what does Perseverance do?

Modern robotic space exploration involves high-tech missions and sensor-laden mobile laboratories like Perseverance. This huge, comparable in size to an SUV (dimensions 2.9x2.7x2.2 m), heavy (1025 kg) rover is supposed to focus on life. Both the past life, if it existed on Mars, and the future life. The rover is exploring the Jezero Crater, a geologically rich environment, a former river delta. This is the place where it is easiest to find traces of possible life.

Perseverance is also collecting soil samples for future transport to Earth as part of the Mars Sample Return mission under development. It also conducts experiments whose results will serve future marsons. One of them is “MOXIE”. It is an experiment to see if oxygen can be produced from Martian carbon dioxide. The experiment went successfully, in April 2021 MOXIE produced oxygen.

The device design is based on a previously constructed so-called MIP, or Mars In-situ propellant production Precursor. It was developed for the canceled Mars Surveyor 2001 lander mission. And here we touch on an important issue: the distinction between rovers and landers.

The Martian rover — the beginnings of Mars exploration

Robotic exploration of Mars began with the Soviet Mars 2 lander, which crashed into the surface of the Red Planet in August 1972. It took a few more years before NASA’s Viking 1 and Viking 2 landers safely settled on Mars, and while they were the most successful Mars missions for many years, and the program itself was rated very highly, Viking lacked one thing — the ability to move around Mars. Because the lander, as the name suggests, is supposed to land and that’s where its movement ends. It examines the environment, analyzes samples, transmits sensor data, and that would be it.

Also landing was the InSight probe, which settled on Mars in November 2018. For the purposes of this mission, a so-called mole was made, which is a penetrator designed to penetrate under the surface of the planet. Unfortunately, the lander settled on a layer of regolith unsuitable for this type of research. The mole could not penetrate to the right depth and the lander itself had no way to move.

Mars rover — Sojourner, Spirit and Opportunity

Therefore, a rover is the optimal solution. Historically, the first Mars rover was the Pathfinder mission’s small, six-wheeled Sojourner. The rover was 65x50x40 cm, weighed just over 10 kg and was powered by solar panels. It was only a dozen or so meters away from the lander, yet it performed several chemical analyses and sent back over 550 images.

Thanks to him, it was already known that in order to learn about Mars, it was necessary to explore it with mobile robots. However, the next rovers had to wait almost 10 years. In 2003, the Spirit and Opportunity twins landed on Mars. They were much larger than Sojourner. Their dimensions are 1.6 x 2.3 x 1.5 m and weight — 185 kg. Designed and manufactured at NASA’s Jet Propulsion Laboratory (JPL), they were supposed to operate on Mars for only 90 days. However, they worked for 3 and 15 years respectively. Thanks to them, we learned about the conditions on Mars, learned a lot about the chemical and geological processes on the planet, and obtained a huge photo base.

The twins, and especially the bravest Martian rover in history, Oppy (short for Opportunity), have also started a veritable worldwide rover boom. NASA’s sub-site, which published information provided by Oppy, was the agency’s most visited sub-site. And when the rover’s panels were covered in sand, which consequently led to the end of the mission in 2018, thousands of people from all over the world sent virtual cards to the rover wishing it a good recovery.

The Mars rover — how is it controlled?

The aforementioned JPL is the main place for designing, executing and commanding NASA rover missions. It houses the so-called Mars Yard, which is a warehouse and martian track where twin versions of Mars rovers are stored. They are used to solve problems on Earth that the rovers encounter on Mars. Thanks to these tests, scientists know what commands to implement to solve the problems of devices operating on the distant planet.

All Mars rovers, including the modern Perseverance, are controlled from Earth. That’s why they move extremely slowly, passing a few dozen or so meters a day. This is related to the time necessary to send the signal. In the optimal arrangement of the Earth and Mars, the time between sending information from Mars, and receiving by the rover command from the Earth, is a minimum of 15 minutes. And that’s if everything works smoothly. When the arrangement of the planets changes, this time can extend to several tens of minutes, or even an hour. If the rover traveled fast, the operator would not have the opportunity to react in a situation when on the path of the robot would find a dangerous cleft or stone.

However, artificial intelligence algorithms are being developed at JPL that, working with the Earth operator, would help the rover better plot its path. Other helpers will be future versions of Martian helicopters, such as Ingenuity, which could also assist in choosing the optimal path. Because there are many indications that by the time humans set foot on Mars, it will be the only planet in the solar system inhabited exclusively by robots for a long time to come.