The images gave the world a glimpse of an often completely invisible process, including the deployment of the parachute to slow the spacecraft after it entered the atmosphere.
The 70.5-foot supersonic parachute was an extraordinary engineering challenge, said Ian Clark, systems engineer at NASA’s Jet Propulsion Laboratory in Pasadena, California. Clark, who has been with JPL since 2009, has worked on the parachute for years. He conducted three tests on Earth to make sure the parachute could survive in a wind twice the speed of sound, or Mach 2.
“We’ve been doing tests that hadn’t really been done since the Viking program (in the 1970s and 1980s), which was supersonic scaling parachute testing,” Clark said.
The parachute tests were conducted at NASA’s Wallops Flight Facility in Virginia in 2017 and 2018. The test team replicated the Martian environment by using probing rockets to reach the mid-edge of space at twice the speed of sound and deploying the parachute.
Nylon, Technora and Kevlar were used to create the largest parachute ever sent to Mars, material that was three times stronger than what was used for the Curiosity rover’s 2012 landing.
The team was confident in their tests, but it all came down to the parachute’s main performance on Mars.
A secret code
Easter eggs have a history as part of the missions NASA sends to Mars. For example, thanks to small holes in the wheels, the Curiosity rover – which Gale Crater has explored – leaves behind “JPL” marks in Morse code as it travels through the Martian landscape.
While working on the parachute design, Clark knew it would be of great use to create a pattern. Cartridges on parachutes help convey its orientation, how it is inflated, and whether there is damage after inflation. Checkerboard patterns can be confusing, so Clark wanted to use something less uniform and clearer.
Then Clark and some of his teammates decided to have a little fun.
Clark is a puzzle enthusiast. He does the New York Times crossword every morning. His mother also keeps the Sunday edition puzzles in a manila envelope that she gives him every time he visits her.
He thought about coding words with binary code. But what would the message be? Although he has never been one to look at a motivational poster and take much meaning from it, Clark noticed three words: “Dare to do mighty things.”
The motto, taken from a speech by Theodore Roosevelt, is in buildings all over the JPL campus.
“Week after week, I never got tired of reading ‘Dare Mighty Things’,” said Clark. “And it’s not just the phrase, but it’s even the broader context of the speech. This amazing inspirational message really represented the culture of JPL and NASA as a whole.”
He also posted the GPS coordinates for JPL on the outer ring of the parachute.
At a press conference where the video was shared with the public on Monday, Allen Chen teased before entry, descent, and landing that there might be something to decipher in the orange-and-white parachute.
Within hours, space fans began posting what they had deciphered on Reddit and Twitter. Clark was excited to see others engaged in this type of puzzle solving, especially so quickly, as well as the joy that spread after the video of Mars was shared.
Clark hopes The Perseverance’s images and videos will inspire people and help them get through the challenges of their days.
Inspiration becomes reality
Missions exploring the solar system such as Voyager, Galileo, and Cassini have long inspired Clark.
As a child, Clark watches Carl Sagan’s “Cosmos”, the 1980 PBS show recorded by his father. Clark saw Sagan talk about the billions of stars in the universe and shared the first images returned by the Voyager probes as they passed Jupiter and Neptune. It piqued his curiosity and made him want to get involved in aerospace engineering.
Even the slightest thing can cause damage to the parachute “and ultimately lead to a bad day because of the chaos of the environment,” Clark said.
Wind moving in the wrong direction can have a catastrophic effect, blowing the parachute inside out and destroying itself. Those who work on the entry, descent and landing often point to the parachute as one of the aspects of a mission that scares them the most, as it is one of the least predictable of the mission.
When Mohan said the parachute had been deployed, Clark monitored the spacecraft’s speed as it fell through the atmosphere. At first it seemed a bit too fast, given the distance between the robber and the ground.
But the parachute did its job, slowed the rover and landed gently in a perfect way.
As images and videos of the descent began to return, Clark finally knew that the team’s efforts had paid off and that the parachute had blown up beautifully.
“The realization of what had happened began to bubble to the surface,” said Clark. “I said to the person who sent me the images, ‘I think I feel happy for the first time today.’ ”
Exploring Mars
With each mission, NASA builds on previous successes. This first video of a spacecraft landing on Mars will be used by teams planning other missions for decades, Clark said.
The importance of these types of images cannot be overstated.
Some of the first parachute tests conducted for a Mars mission took place during the Viking program nearly 50 years ago. Images from the tests on 16-millimeter film were thought to have been lost to history, Clark said. But they were able to track it down to someone who donated it to a small museum in Bradenton, Florida.
Clark flew from Los Angeles to pick up the film and have it restored and digitized. Now the images are used to compare with their recent parachute tests.
Clark continues to work on the Perseverance mission in a variety of ways. He was the assistant project systems engineer for monster purity, ensuring that the samples that the Perseverance rover collects on Mars in its quest for ancient life are not contaminated by anything from Earth.
Those samples will be returned to Earth in the 2030s by follow-up missions called Mars Sample Return. Clark will be the phase conductor for the mission that will retrieve those samples from the surface of Mars and return them to orbit before returning to Earth.
“We’ve been wanting to do this kind of mission for nearly six decades now,” said Clark. “If we dare to do great things, we can achieve truly phenomenal success.”