October 4, 2023

NASA’s newest robotic researcher will reach Mars on Thursday afternoon, the third spacecraft to arrive on the planet this month after visitors from the United Arab Emirates and China. The Perseverance Rover is on its way to Jezero Crater, a place that planetary researchers believe is an ideal place to find surviving signs of life from billions of years ago, should life ever arise on Mars.

But first, NASA’s mission has to land in one piece.

Touchdown is expected around 3:55 p.m. Eastern Time. NASA television will broadcast coverage from the mission control room at the Jet Propulsion Laboratory in California starting at 2:15 p.m.

During the descent, the spaceship sends updates on how it works. Since the main antenna does not point to the earth, direct communication is just a series of simple tones.

“We can use these tones to tell us different things, like the heat shield peeled off or something,” Allen Chen, the chief engineer for the landing portion of the mission, said at a news conference Wednesday.

It is possible that Perseverance could send back some photos of the surface via NASA’s Mars Reconnaissance Orbiter, but it could take hours for them to arrive. “If we get this, it’ll be golden,” said Jennifer Trosper, an assistant project manager for the mission.

In short, the persistence must slow to a standstill from more than 19,000 km / h during the period from the rover’s entry into the atmosphere to its landing. There is no chance for a revision. The path of perseverance will cross the surface of Mars. The only question is whether the rover will end in one piece, ready to begin its mission, or will be shattered into many pieces.

Mars’ thin atmosphere adds several levels of difficulty. A spaceship needs a heat shield because the friction of air molecules heats its underside to thousands of degrees. But there isn’t enough friction to slow it down for a soft landing with just parachutes.

The spaceship must carry out the landing process alone. It takes 11 minutes for a radio signal from Mars to reach Earth. That said, if something went wrong, it would be too late by the time the people at NASA’s Mission Operations Center found out about it.

“It all has to be done autonomously,” said Matt Wallace, assistant project manager. “Perseverance really has to fight its way to the surface. It’s like a controlled dismantling of the spacecraft. “

About 80 seconds after entering the atmosphere, the spacecraft experiences peak temperatures, with the heat shield at the bottom of the capsule reaching 2370 degrees Fahrenheit. It’s much less roasted in the capsule – at room temperature. When the air becomes denser, the spaceship continues to slow down.

Small engines fire on top of the capsule to change the angle and direction of their descent and keep them on course for their landing site.

At an altitude of about seven miles, four minutes after entering the atmosphere, the capsule is moving at a speed of less than 1,000 miles per hour. Then a giant parachute, more than 70 feet in diameter, is deployed.

The spaceship will now drop the heat shield so cameras and other instruments can look at the terrain below to determine its position.

Even with the giant parachute, the spaceship is still falling at a speed of about 200 miles per hour.

The next crucial step is the sky crane maneuver. The top of the capsule, the so-called backshell, is released and carried away by the parachute. There are two parts of the spacecraft left. The top is the descent stage – essentially a rocket propelled jetpack that carries the rover underneath. The motors of the descent stage fire and steer first to avoid a collision with the rear shell and the parachute. Then the engines slow the descent to less than two miles per hour.

The rover is then lowered on cables about 30 meters above the surface. The descent stage continues down until the rover’s wheels touch the ground. Then the cables are cut and the descent step flies away to collide at a safe distance from the rover.

It has worked before. The Curiosity rover, currently on Mars, successfully deployed the same landing system in 2012. Spacecraft, however, are complex systems and one success does not guarantee a second success.

Endurance has stronger parachutes and a more precise navigation system. NASA engineers say they tried every step to improve the chances of everything working, but they don’t know if they figured out all of the eventualities.

“We’ve never really found a good way to calculate the likelihood of success,” said Wallace, the assistant project manager.

Over the decades, NASA succeeded eight out of nine attempts to land on Mars. The only flaw was the Mars Polar Lander in 1999.

Steve Jurcyzk, NASA’s acting administrator, admitted in an interview, “I’m going to be extremely nervous.”

Over the past 20 years, NASA has gradually asked more complex questions about Mars. First, the mantra was “Follow the water” because there may have been life there once. With huge canyons, winding river channels, and signs of dried-up lakes, it was clear that water flowed on Mars in the past, even though the planet is now cold and dry.

The goal of Perseverance is the Jezero crater. The rover will explore the delta of a river that once flowed into a lake that filled the crater. The sediment heaps are a promising place where the fossil chemical signatures of the ancient Martian microbes could still be preserved today.

The rover has largely the same design as the Curiosity rover, which is now examining the Gale Crater. However, there are a number of other instruments available, including sophisticated cameras, lasers that can be used to analyze the chemical composition of rocks, and ground penetrating radar. Tests of these tools on earth showed the possibility of finding preserved past life signs.

NASA’s new rover carries a four-pound helicopter called the Ingenuity, which is attempting something never before done: the first controlled flight on another world in our solar system.

Flying on Mars is no trivial undertaking. There isn’t a lot of air there to push against to create buoyancy. On the surface of Mars, the atmosphere is only 1/100 as dense as that of Earth. The lower gravity – a third of what you’re feeling here – helps get into the air. Lifting off the Martian surface, however, is equivalent to flying through the air as thin as 100,000 feet above Earth. No land helicopter has ever flown this high, and that’s more than twice the height at which jetliners normally fly.

NASA engineers took advantage of a number of advances in materials and computer technology to address a number of these challenges. About two months after landing, Perseverance will drop the helicopter from its belly, and Ingenuity will attempt a series of about five test flights of increasing duration.

If the tests are successful, this could pave the way for future, larger Marscopes. The ability to use robotic airplanes could greatly expand a space agency’s ability to study the Martian landscape more closely, just as the transition from stationary landers to rovers did in previous decades.