Imagine trying to land a rover the size of an SUV on another world. That alone is a challenge, but imagine doing so while the rover is hanging precariously beneath a floating sky crane, connected to it only by a handful of clothesline-like nylon cables.
In a matter of minutes and without external assistance, the spacecraft must slow down from 21,000 km/h to zero to ensure that the sky crane gently lowers the rover wheels first to the surface so that it can carry out the scientific mission it was designed for. They have only one attempt for the landing, during which the rotation of the Red Planet will keep the rover out of sight of the Earthand you cannot communicate directly with him and learn of his success or failure for a short but agonizing period.
Sounds like a science fiction novel, doesn’t it? Yet NASA scientists and engineers achieved such a daring feat 12 years ago this month, when such an unprecedented, death-defying jump brought a new robot inhabitant to Mars — curiosity – and set the stage for future missions to the Red Planet.
“Seven Minutes of Terror”
The first three Mars Rover—Pathfinder, Spirit and opportunity – landed wrapped in giant, inflated airbags that bounced on the Red Planet’s surface more than 15 times before coming to a slow stop. For the car-sized Curiosity, however, calculations showed that the existing airbags wouldn’t work. And even if they did, there was no known material that could support the rover’s one-ton weight.
Related: Curiosity Rover: The Ultimate Guide
Oh, how Mars landings have changed. Pathfinder used giant airbags to land on the Red Planet. A decade later, @NASAJPL developed the Sky Crane maneuver to safely land @MarsCuriosity and @NASAPersevere. More on this engineering development: https://t.co/YPfZSLq6TQ pic.twitter.com/dvxja7gV468 August 2024
The only way to lower Curiosity to the surface was to use a rocket-powered sky crane, which in turn was lowered by the Mars atmosphereBut the mission team wasn’t sure how to suspend a rover the size of Curiosity without it swinging dangerously. Inspired by similar sky cranes that carry cargo helicopters on Earth, the team eventually incorporated similar technology into Curiosity’s jetpack so that it could sense and control the swinging.
“All this new technology gives us a real chance of getting to the right place on the surface,” said Al Chen of NASA’s Jet Propulsion Laboratory (JPL) in Southern California, who played a key role in the entry, descent and landing (EDL) phase of the Curiosity mission, in a latest statement from NASA.
Curiosity’s complicated and nerve-wracking landing attempt, in which some of the mission’s staff emotionally frightenedwas described as “seven minutes of terror.”
Although Curiosity was guided and monitored by its team of 400 scientists and engineers during its eight-month space journey, the $2.5 billion mission was largely left to its own devices during the seven-minute EDL. The last command from Earth was sent two hours earlier. And because of the time lag between the two planets, scientists didn’t know whether Curiosity had landed safely or crashed until about 15 minutes after the event.
“In terms of the team’s control during entry, descent and landing, it’s identical to the control any viewer has at home,” said Adam Steltzner of JPL, who led the EDL phase for Curiosity. told reporters shortly before Curiosity’s landing attempt. “We’re all there.”
The flight was deemed flawless after Curiosity’s six wheels touched down as planned in the 154 km wide Gale Crater and its ten scientific instruments worked perfectly. Scientists and engineers sitting in the JPL mission control center jumped up and down with joy when they received confirmation that Curiosity had landed safely.
“The right kind of madness”
When the novel Skycrane EDL approach took shape in the early 2000s and was considered the only way to land a heavy rover on Mars, it was so frighteningly daring that few scientists or engineers were convinced by the idea, not least because NASA had recently Sensational failures on the Red Planet.
In particular, the idea that the jetpack would be placed above the rover in the planned mission and not below it as usual worried many people, recalls JPL fellow Rob Manning, who worked on the original idea in 2000.
“People were confused by this,” he said in the NASA statement. “They assumed that the propulsion would always be below us, like you see in old science fiction stories when a rocket lands on a planet.”
However, a lander’s engines would not only kick up debris during descent, making it difficult for Curiosity to descend; they could also dig a hole in the ground from which the rover would be unable to exit. By placing the engines above the rover, the mission team ensured that the wheels would touch down directly on the surface, eliminating the additional weight of a landing platform on an already heavy spacecraft.
“We talked about it endlessly,” said Steltzner Eric Betz from Astronomy“If it doesn’t work, you can’t hide anymore, because any normal person on the street would say they knew it wouldn’t work.”
Then-NASA administrator Mike Griffin told the mission team the idea was crazy, “but it might be crazy enough to work. It might be the right kind of crazy.”
Related: NASA: Landing a giant Mars rover with a sky crane was the “least crazy” idea
What’s the deal with the landing? 🥇12 years ago, I needed 76 pyrotechnic devices to land on the Red Planet and had no room for error – and my team absolutely nailed it. Do you remember the drama of those “7 minutes of terror”? pic.twitter.com/5iZd7PSQax5 August 2024
The novel technology proved so successful that in 2021, NASA used the same skycrane method to successfully land another rover. Endurancewhich only last month amazed the scientific community – and the world – with its Discovery of a Martian rock which may contain traces of prehistoric life.
Scientists say the same technology could be used for larger spacecraft that could travel not only to Mars but also to other destinations in the solar system“If you want a payload delivery service in the future, you can easily use this architecture to access the surface of the moon or elsewhere without ever touching the ground,” Manning said in the NASA statement.
What curiosityThe rover continues to roam the Martian landscape in search of Signs of former habitable conditionsmore than 12 years after his groundbreaking landing.
