When NASA’s Perseverance rover fell through the Martian atmosphere last week, a video camera from the spacecraft captured the breakneck deployment of its parachute, adorned with patches of reddish orange and white.
These spots were classified as secret news.
During a press conference on Monday, Allen Chen, the engineer in charge of the landing system, told what to see and learn from the slowed-down video.
Cryptic and casual, he added that his team hoped to inspire others. “Sometimes we leave messages in our work that others can find for that purpose,” he said. “So we invite all of you to try it out and show your work.”
Across the Atlantic Ocean, Maxence Abela, a 23-year-old computer science student in Paris, realized what Mr. Chen was saying: The seemingly random pattern on Perseverance’s parachute contained a code.
He called his father Jerome, a Google software engineer who works in London, and the two of them went to work to solve the problem.
“We like such little challenges,” said Abela. “We didn’t think we could solve it, but at least we’d try.”
They collaborated on a conference call, downloaded the video, isolated images showing the parachute fully inflated, and began piecing together the bits.
Others around the world shared insights on Twitter and forums on Reddit. “It’s just exciting that NASA is bringing these little puzzles into their missions,” said Adithya Balaji, a PhD student in computer science at Carnegie Mellon University in Pittsburgh who approached the problem independently.
Mr. Balaji compared the parachute puzzle to some science fiction films: “Contact”, in which a scientist played by Jodie Foster unravels an extraterrestrial message, and “The Martian,” in which Matt Damon’s character Mark Watney talks to humans on Earth communicates a similar code.
“I find it exciting that real life can sometimes be even more exciting than the movies,” said Balaji.
The person who came up with the idea to embed a message was Ian Clark, who led the development of the parachute. NASA’s previous rover, Curiosity, used the same system when it successfully landed on Mars in 2012. However, failure of a prototype parachute for future missions spurred engineers to improve on the design.
While watching a video of an altitude test of the new parachute for endurance, Dr. Clark that the checkerboard pattern on the canopy made it difficult to see how parts of the parachute unfolded and inflated.
Since Perseverance would be equipped with video cameras, Dr. Clark a pattern that is visually different. Again, this was an opportunity to “have a little fun with it,” he said.
He asked permission from Matt Wallace, an assistant project manager for the mission.
“I told you OK,” recalled Mr. Wallace. “Just make sure that it is appropriate and that it cannot be misinterpreted.”
The 70 foot wide parachute was made up of 80 strips of fabric radiating outward from the center to form a hemispherical canopy, and each strip was made up of four pieces. Dr. So Clark had 320 pieces to work with.
Some of his ideas would have required additional colors, but that could have compromised the integrity of the parachute if untested dyes had weakened the fabric fibers.
“We didn’t want to go to a cloth that was dyed a color that we had never used before,” Wallace said.
Even a pattern of just orange and white, the two colors of previous parachutes, posed potential problems. “There are all kinds of questions to think about,” said Dr. Clark. “How could more white than orange or vice versa mean that the parachute would heat up differently and perhaps this would change its behavior?”
After all, the mission managers would have been embarrassed to have to explain how they lost a $ 2.7 billion mission to a parachute engineer sneaking into a classified message.
But Dr. Clark’s analysis showed no ill effects, and the plan was moving forward. As of this week, only about half a dozen people knew about it.
When computer scientists see something in black and white – or in this case, orange and white – they think of binary code, the ones and zeros that are the language of computers. This was the first clue that the puzzle solvers followed on Monday.
For each orange section on the Parachute of Perseverance, Maxence Abela and his father wrote down a 1, and for each white section they assigned a 0. This resulted in a long string of ones and zeros.
They thought that maybe the digits could be converted into an image, like the message scientists sent from the Arecibo radio telescope in Puerto Rico in 1974 to tell distant extraterrestrial civilizations of people on Earth.
“We couldn’t find anything that looked like anything,” said Mr Abela.
They tried to divide the digits into groups of eight – a common practice in computer programming – but that also produced gibberish.
Then the elderly Mr. Abela noticed that the digits seemed to fit in groups of ten. “Every 10 bits would be three zeros in a row,” said Maxence Abela. It is not a coincidence.
However, the resulting numbers didn’t make any sense until they realized they had read the ones and zeros in the wrong direction, counterclockwise instead of clockwise. When they wrote the digits in reverse order, the 10-digit parts of the binary code were translated into small numbers that could then be assigned to letters. The number 1 corresponded to the letter A, the number 2 was B, 3 was C, 4 was D and so on.
The message on the inner three ring tones: “DARE MIGHTY THINGS.”
Mr. Abela posted his response on Twitter at 4:36 p.m. Eastern Time, approximately two hours after Mr. Chen dropped his cryptic tip during the press conference.
This is a creed often quoted in NASA’s Jet Propulsion Laboratory in California, which built and operated Perseverance. It comes from “The Strenuous Life”, an 1899 speech by Teddy Roosevelt: “It is far better to dare to dare powerful things to achieve glorious triumphs, though they have been slowed down by failure, than to measure yourself against the poor spirits who neither enjoy much. ” nor suffer much because they live in a gray twilight that knows neither victory nor defeat. “
There were still a few numbers and letters in the fourth ring that none of Abela could understand. It found that this was the longitude and latitude of the NASA center: 34 ° 11’58 ”N 118 ° 10’31” W.
“If you look in Google Earth and put in those coordinates, you are probably about 10 feet from the JPL visitor center door,” said Dr. Clark.
In the evening Adam Steltzner, the chief engineer for persistence, posted an annotated diagram explaining the solution.
The parachute wasn’t the only fun the builders of the Perseverance Rover had.
Eagle-eyed observers discovered a series of drawings depicting the five rovers NASA sent to Mars, from the little Sojourner in 1997 to the Perseverance.
A plaque that is used to calibrate one of the rover’s main cameras has spots of paint on it, but there are also quirky drawings that include DNA, a rocket, and a dinosaur.
There is an inscription on the edge of the calibration board: “Are we alone? We came here to look for signs of life and to collect samples from Mars for study on Earth. We wish those who follow a safe journey and the joy of discovery. “
Elsewhere on the rover is a piece of a Martian meteorite that landed on Earth and is now back on its original planet. This is to be used to calibrate SuperCam, an instrument that uses lasers and a camera to identify carbon-based molecules and other compounds in rocks and soils. (Before returning to Mars, the same well-traveled rock made a round trip to the International Space Station.)
There are also three small chips on Perseverance with the names of 10.9 million people who stand on stencils. This is part of NASA’s effort to get the public to participate in their robotic missions. A more solemn addition was an aluminum plate that takes into account the needs of those affected by the coronavirus pandemic.
The practice of adding fun or festive parts to spacecraft is not new. In NASA jargon it is called “festooning”. The two Voyager spaceships that are now in interstellar space have disks full of images and sounds of the earth. Two previous Mars rovers, Spirit and Opportunity, had parts made from the rubble of the World Trade Center. The New Horizons spacecraft, which passed Pluto in 2015, carries some of the ashes of Clyde Tombaugh, the astronomer who discovered this world.
When it comes to endurance, there are still a few surprises to be revealed.
“There are some things on the front of the vehicle that we can see when we deploy the robotic arm,” said Wallace. He declined to say what they were or to give any clues.
“We’ll let people enjoy the pictures when it comes down to it,” he said.