Monday after midnight, a white rover named Curiosity is supposed to land on Mars and begin a 23-month expedition to figure out whether the planet can – or ever could – harbor life.
The mission is the most scientifically advanced attempt at exploring Mars and it took NASA seven years and $2.5 billion to prepare. The minutes before landing will stretch the nerves of the agency’s crew, including propulsion engineer and Wichitan Todd Barber.
Barber, who has worked with NASA’s Jet Propulsion Laboratory since 1990, describes himself as a remote “space plumber.” His work during Curiosity’s nine-month cruise from Earth to Mars involved checking the pressure and temperature in Curiosity’s propulsion system, its thrusters, tanks and heaters.
“It’s very similar to golf – you’ll never get your hole in one, so you take shots along the way,” Barber said. “We fire the rocket engines to correct the trajectory slightly along the way. And those maneuvers get smaller and smaller as you get closer to Mars.”
A week before its projected landing, Curiosity was on track to enter the Mars atmosphere at 12:31 a.m. CDT on Monday. That’s when the nerve-racking part will begin.
The seven minutes in which Curiosity is projected to travel from the top of the Mars atmosphere to its surface are referred to by NASA engineers as the “entry-descent-landing” stage. They also call it the “Seven minutes of terror.”
Curiosity will enter the top of the atmosphere at 13,000 mph and will have seven minutes to reduce its speed to zero mph and land safely. Because it takes approximately 14 minutes for the signals from the spacecraft to reach Earth, the NASA crew will not be able to directly control the landing.
By the time they receive the signal that Curiosity has entered the atmosphere, the robot will already have landed – or crashed – on the surface.
Everything that happens during those seven minutes was pre-built into the spacecraft and will be triggered by timing, sensors and luck.
As the spacecraft enters the atmosphere, it will heat up to 1,600 degrees and start shining like the surface of the sun. A supersonic parachute – the strongest NASA has built so far – will pop up to slow the spacecraft.
At that point, the heat shield meant to protect Curiosity during the descent will be dropped. The parachute will slow the spacecraft to about 200 mph, at which point the rover will be detached from the spacecraft and will come down with the aid of eight powerful rockets.
At about 20 meters above the surface, the rover will be lowered on a tether and placed safely on the ground. Then, the tether will be cut and the rocket mechanism will fly away, leaving Curiosity alone and ready to start exploring.
“You can do everything right, if one little thing is wrong or if Mars throws you a bad day, with a dust storm or a sharp rock right below the rover ... ” Barber said. “We’ve done everything we reasonably can to ensure success. The rest is up to fate.”
Elaborate equipment, high stakes
Curiosity is the first Mars rover to use rockets in its descent and landing stage. The previous Mars rovers – Sojourner, which landed in 1997, and twin rovers Spirit and Opportunity, which landed in 2004 – used airbags for landing. Curiosity was too big for airbags.
The nuclear-powered rover weighs 2,000 pounds and is about the size of a car – bigger than a Mini Cooper, Barber said. Comparatively, Sojourner was the size of a microwave and Spirit and Opportunity resembled golf carts.
Curiosity was built so that it could incorporate the most ambitious set of scientific tools ever to be sent to Mars. It is the first mobile laboratory on another planet that can perform not only geology tests, but also chemical analyses.
“We’re looking for the kind of conditions where life could have formed,” Barber said. “This is not a life-detection mission; we are not looking for live things there today.
“But we are landing in a place on Mars that was probably pretty hospitable for life, given it was low and had a thicker atmosphere and liquid water at one time.”
Curiosity is equipped with a robotic arm that can pick up rock samples and an oven-like laboratory for analyzing them. It also has a laser – Barber calls it the “Martian death ray” when he tries to explain it to children – that can vaporize rocks from 25 feet away, and analyze the substances in the vapors. It can snap high-definition pictures, and it has a radiation detector so that scientists will know what kind of protection suits to build for the astronauts who will one day land on Mars.
NASA staff sometimes talks about the possibility of a human mission to Mars, Barber said. It would take serious funding and political resolve. It would maybe need a decade of planning and research.
It would be a three-year mission, including the 18 months on the road – nine each way – and the 18 months that astronauts would have to wait for Earth and Mars to realign for the return trip.
“But I’d go in a heartbeat,” he said.
Realistically, Curiosity might be NASA’s only Mars mission this decade. A successful landing Monday night is paramount for for NASA’s reputation, in a time of difficult funding. It’s also important for the team’s morale.
“When we have lost robots they sent in grief counselors,” Barber said. “You work with them so much (that) sometimes you see them more than your families. They all have quirky personalities and their own individuality.”
‘I miss Wichita every day’
Barber will be waiting for Curiosity’s landing signals with his colleagues at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Every landing mission is an intense experience, he said. Time slows down like in an accident, breathing gets labored, the heartbeat intensifies, and nervousness kicks in.
“And then, assuming everything works, there’s just no better feeling in the world,” he said. “The relief that all the years of work and all the people that have put their heart and souls into it is paying off in this one moment.”
Barber’s friends and family in Wichita will be able to watch Barber watching Curiosity. Two Wichita channels – Cox Cable Channel 20 and AT&T U-verse Channel 99 – will carry NASA TV live during the event.
Barber’s parents watched their son on TV on the previous missions he worked on – the insertion of the Galileo spacecraft on the Jupiter Orbit in 1995, and the landing of Spirit and Opportunity rovers on Mars in 2004. For the Cassini mission to Saturn in 2004, Barber’s parents were guests at the official viewing at Exploration Place.
Barber said he considers himself “a product” of Wichita public schools. He graduated from Southeast High School in 1984 and attributes his passion and success in propulsion engineering to three of his high school teachers: math teacher Sue Neal, chemistry teacher Floyd Bayer and physics and astronomy teacher Marion Hodges.
Barber got his bachelor’s and master’s degrees from the Massachusetts Institute of Technology and was hired by NASA right out of college. He has kept in touch over the years with his family, friends and teachers in Wichita. He sometimes gives speeches at his former high school, hoping to encourage other kids to walk his path.
Most recently, Barber was back home a couple of weeks ago, when he attended his grandmother’s 100th birthday celebration in western Kansas.
“Between that and hopefully sticking a landing on Mars,” he said, “I think this will be a summer I’ll never forget.”