NASA has done it. The largest and most sophisticated spacecraft ever sent to another planet has landed safely on the surface of Mars. We live-blogged Curiosity's arrival, but for those of you who couldn't watch it live, here's what we saw during the most remarkable Mars landing in history.
That's not exaggeration, by the way. Curiosity's arrival was epic, and — by pretty much all accounts — flawless.
In the days and hours leading up to the landing, the rover was described as being in excellent shape. Last night, at 21:12 PT, a little more than an hour before entering Mars' atmosphere, the uplink transmitter between Curiosity and NASA's Jet Propulsion Lab in Pasadena was intentionally switched off. The crew at JPL had guided Curiosity along its journey for as long as it could, but given that it takes light 14 minutes to make the trip from Earth to Mars, controlling the spacecraft directly from Earth was out of the question; Curiosity had been programmed to perform all of its entry, descent and landing maneuvers autonomously. Having no input from JPL meant that If the rover was going to land safely, it was going to have to do so entirely on its own.
All that was left to do was watch and wait, so the crew members at JPL turned to hand-wringing and munching on peanuts.
The snack is a NASA/JPL good luck tradition, and dates all the way back to the Ranger 7 mission in 1964. This screenshot, taken from NASA's livefeed, was captured around 23 minutes before atmospheric entry. The tension at JPL, which had been building steadily for the better part of two hours, was approaching heart-attack inducing levels.
Even Curiosity seemed anxious to arrive. After traveling through space for over eight months at around 8,000 miles per hour, the spacecraft began to pick up speed as it approached the planet, egged on by the ever-increasing pull of Mars' gravitational forces. By the time it hit Mars atmo at 22:25 PT, Curiosity had reached a blazing 13,200 miles per hour. The rover's seven-minute trip from the top of the atmosphere to the surface of the planet (the so-called "seven minutes of terror") had begun.
Events began unfolding rapidly. Less than two minutes after atmospheric entry, JPL confirmed that Curiosity had established a connection with NASA's Odyssey spacecraft, and that the satellite was, in fact, relaying data to Earth. Direct contact between Curiosity and Earth is dependent upon line of sight communication (depicted here with pink dashes). Curiosity was scheduled to lose sight of Earth over the Martian horizon a few minutes after entering the atmosphere, but before landing on the surface of Mars. Odyssey would therefore play a crucial role in relaying real-time signals (depicted here in blue) to Earth. There had been doubts over whether Odyssey would be a) in the right position, and b) able to relay communications to Earth during Curiosity's landing. The fact that it had managed to accomplish both was a huge success.
Things only got better from there. Another two minutes passed, and NASA received word that Curiosity's supersonic parachute had deployed successfully, and that the rover was decelerating toward its target, Mars' Gale crater. At 22:30 PT, NASA confirmed that Curiosity had made radar contact with the ground and was traveling at 86 meters per second.
At 22:32, JPL erupted. "Touchdown confirmed," said engineer Alan Chen. "We're safe on Mars."
Our favorite sideburn-sporting rockabilly engineer Adam Steltzner, leader of Curiosity's descent and landing team, was understandably excited:
Minutes later, even more good news arrived when Curiosity beamed back its very first black and white photos of the Martian surface, including these awesome shots showing the shadow of Curiosity in the Mars afternoon sun (on the left), and a view of one of the rover's wheels (on the right). The images appear dusty because the HazCams that captured these photos still had their lens caps on.
In the days ahead, Curiosity will begin unpacking its various scientific systems, and verifying that they're all in good shape. It is then that we will receive even bigger, color pictures from Mars. If Curiosity's Mastcam instrument is successfully deployed and in working order, NASA predicts we'll have our first 360-degree color panoramas of Curiosity's landing site as early as Wednesday or Thursday. Once curiosity is all unpacked and has a good feel for its surroundings, it will set out on its scheduled two year mission, in search of the building blocks of life.
A lot has been said about the overwhelming success of the mission thus far. According to Steltzner, "we landed in a nice flat spot. Beautiful, really beautiful." President Obama weighted in as well, describing the landing as "an unprecedented feat of technology that will stand as a point of national pride far into the future."
But one of our favorite summaries of the night's accomplishments came from JPL director Charles Elachi shortly after touchdown.
"Tonight was a great drama," he explained matter-of-factly. "Tomorrow we're going to start exploring Mars... And next week and next month and next year, we'll be bringing new discoveries every day, every week, to all of you.
"Our Curiosity has no limits, and we will explore the solar system."