NASA's Mars rover Perseverance landed on the Red Planet on Thursday after a roughly 480-million-kilometer (298-million-mile) journey through space, the first probe from Earth to reach Mars since 2018.
"Touchdown confirmed, Perseverance safely on the surface of Mars," a NASA announcer said during a live broadcast of the landing.
The landing sequence, known as the "Seven Minutes of Terror," saw Perseverance enter Mars's atmosphere at a speed of 20,000 kilometers per hour (12427.42 miles per hour) before deploying thrusters and a parachute to rapidly slow its descent.
Since it took more than 11 minutes for the NASA team to receive a radio signal back from Mars, the entire process was complete before NASA received notice of the rover's successful landing.
"Hello, world. My first look at my forever home. #CountdownToMars," tweeted the Rover on its Twitter account.
"And another look behind me. Welcome to Jezero Crater," it added in another tweet.
Perseverance has landed in the massive Jezero crater that used to be a lake, where it will begin a search for evidence of ancient microbial life.
Debates over life on Mars
Was there ever life, as we know it, on Mars, the red planet of the solar system? After decades in the making, seven months in space, a 480-million-kilometer journey and $2.7 billion, NASA's Perseverance mission is to answer that very question.
NASA's Perseverance rover has touched down on the Red Planet to search for telltale signs of microbes that might have existed there billions of years ago when conditions were warmer and wetter than they are today.
Over the course of several years, it will attempt to collect 30 rock and soil samples in sealed tubes, to be eventually sent back to Earth sometime in the 2030s for lab analysis.
"It's of course trying to make significant progress in answering one of the questions that has been with us for many centuries, namely: are we alone in the universe?" NASA Associate Administrator Thomas Zurbuchen said Wednesday.
Perseverance is the largest and most sophisticated vehicle ever sent to Mars.
About the size of an SUV, it weighs a ton, is equipped with a 7-foot (2-meter) long robotic arm, has 19 cameras, two microphones, and a suite of cutting-edge instruments to assist in its scientific goals.
The rover also survived the "seven minutes of terror" – the risky landing procedure that has scuppered nearly 50% of all missions to the planet. Since it takes over 11 minutes for the NASA team to receive a radio signal back from Mars, the entire process was over when they received notice that Perseverance has entered the atmosphere.
Shortly after 3:30 p.m. Eastern Time (2030 GMT), the spacecraft careened into the Martian atmosphere at 12,500 miles per hour (20,000 kilometers per hour), protected by its heat shield. It then deployed a supersonic parachute the size of a Little League field, before firing up an eight-engined jetpack to slow its descent even further, and then eventually lowered the rover carefully to the ground on a set of cables.
Its target site, the Jezero Crater, is full of perilous terrain, but thanks to new instruments, Perseverance is capable of landing with far greater precision than any robot sent before it.
Astrobiology dream
Scientists believe that around 3.5 billion years ago the crater was home to a river that flowed into a lake, depositing sediment in a fan-shaped delta. In fact, NASA even said the crater shared topographical and mineralogical similarity with a famed location in Turkey.
Scientists say geologic samples collected there could give evidence of ancient microbes that previously existed on Mars.
"We have very strong evidence that Mars could have supported life in its distant past," Ken Williford, the mission's deputy project scientist said Wednesday. But if past exploration has determined the planet was once habitable, Perseverance is tasked with determining whether it was actually inhabited.
It will begin drilling its first samples in summer, and its engineers have planned for it to traverse first the delta, then the ancient lakeshore, and finally the edges of the crater. It will study the Mars surface for at least two years as it examines the climate and geology, collects rock and soil samples.
Perseverance's top speed of 0.1 miles per hour is sluggish by Earth standards but faster than any of its predecessors, and along the way it will deploy new instruments to scan for organic matter, map chemical composition, and zap rocks with a laser to study the vapor.
"We astrobiologists have been dreaming about this mission for decades," said Mary Voytek, head of NASA's astrobiology program.
Despite its state-of-the-art technology, bringing samples back to Earth remains crucial because of anticipated ambiguities in the specimens it documents. For example, fossils that arose from ancient microbes may look suspiciously similar to patterns caused by precipitation.
Flying on another world
Before getting to the main mission, NASA wants to run several eye-catching experiments.
Tucked under Perseverance's belly is a small helicopter drone that will attempt the first powered flight on another planet. The helicopter, dubbed Ingenuity, will have to achieve lift in an atmosphere that's 1% the density of Earth's, in a demonstration of a concept that could revolutionize the way we explore other planets.
Another experiment involves an instrument that can convert oxygen from Mars' primarily carbon dioxide atmosphere, much like a plant, using the process of electrolysis to produce 10 grams of oxygen an hour. The idea is that humans eventually won't need to carry their own oxygen, which is crucial for rocket fuel as well as for breathing.
Perseverance's two microphones will meanwhile attempt to record the Martian soundscape for the very first time after past efforts failed.
The rover is only the fifth ever to set its wheels down on Mars. The feat was first accomplished in 1997 and all of them have been American.
That will probably soon change: China's Tianwen-1 spacecraft entered Martian orbit last week and is expected to touch down with a stationary lander and a rover in May.