The NASA Perseverance rover's 293 million mile (472 million km) journey to Mars ended successfully on February 18, 2021, with a picture-perfect landing inside the Jezero Crater. The car-sized, six-wheeled rover, nicknamed Percy, is the US space agency's biggest and most advanced explorer to date. Its primary mission is to search for signs of ancient microbial life on Mars.
"Touchdown confirmed! Perseverance is safely on the surface of Mars, ready to begin seeking the signs of past life!" Swati Mohan, the guidance, navigation, and controls (GN&C) operations lead for the Perseverance mission, declared at about 3:55 p.m. EST. Upon hearing the confirmation, the anxiously-waiting double-masked engineers in the mission control room at NASA's Jet Propulsion Laboratory (JPL) broke out into cheers. Moments later, the hazard cameras attached to the spacecraft sent back a clear black-and-white image of the Martian surface with the rover lurking in the shadow.
Though NASA scientists made it look easy, landing on Mars is extremely tricky. The Red Planet's gravitational pull causes approaching spacecraft to accelerate to high speeds, while its thin atmosphere — just 1 percent that of Earth's — does little to help dissipate the energy and slow it down as it approaches the surface.
The scientists had to use a series of tricky maneuvers to reduce Percy's 12,000 mph (19,000 kmh) speed to a safe landing speed of less than five mph – in just six and a half minutes. The target entry angle also had to be a precise 12 degrees – any steeper, and the spacecraft would burn up; any flatter, and it would bounce off the atmosphere and get lost in space. It is no wonder that the final approach is often referred to as the “seven minutes of terror.”
Upon attaining a manageable speed, Percy briefly hovered over the Martian surface to seek out the perfect landing spot. Its sophisticated navigation system rapidly scanned the area and matched it with maps in its database to find the optimal location. The spacecraft then used its hovering-landing sky crane system to gently alight on flat ground just 114 feet (35 meters) away from hazardous boulders. "We did successfully find that parking lot and have a safe rover on the ground,” said Allen Chen, the head of the rover’s landing team at JPL.
The NASA scientists will spend the next two months testing Percy's state-of-the-art scientific instruments. Once ready, the rover will begin its two-year-long mission to explore the ancient crater's lakebed and river delta — which scientists believe were once filled with water — for fossilized microscopic Martian life. The rock and sediment samples collected will be carefully stored and brought back to Earth for analysis in subsequent missions, conducted in partnership with the European Space Agency (ESA).
"Perseverance is the most sophisticated robotic geologist ever made, but verifying that microscopic life once existed carries an enormous burden of proof,” said Lori Glaze, director of NASA’s Planetary Science Division. “While we’ll learn a lot with the great instruments we have aboard the rover, it may very well require the far more capable laboratories and instruments back here on Earth to tell us whether our samples carry evidence that Mars once harbored life."
Whether Percy succeeds in finding any evidence of ancient alien life remains to be seen. However, we can look forward to some spectacular footage of the Red Planet from the rover's 19 high-definition cameras. Since they are also equipped with microphones, we will also be able to hear — for the first time — what Mars really sounds like.