NASA prepares for Mars missions
Spacecraft and their cargo are rigorously tested before leaving for the red planet. Viviane Richter reports.
While Curiosity explores Mars to see if it could once have harboured life, NASA is preparing a more sophisticated rover to look for signs of life in 2020 before finally sending astronauts to the red planet into the 2030s.
To give their Mars missions the best possible chances of success, NASA rigorously tests its spacecraft and their equipment before launch. Their testing facilities are almost as impressive as their rockets and landers.
To reach Mars, a spacecraft must travel through the cold vacuum of space for nine months. These extreme conditions are recreated at NASA’s Glenn Research Centre in Cleveland. In Vacuum Chamber 5, powerful pumps suck air out of the 4.5 metre tall space. Even a spacecraft’s thrusters can be tested here – it’s designed to handle the heat and gas they generate. Panels cooled to -262°C line the walls, chilling the thruster’s exhaust. Pumps lining the bottom of the tank concentrate and recycle the precious xenon gas that the thrusters blast out as propellant.
After months of floating at near-absolute zero degrees, a spacecraft must be prepared for a blistering shock when it pierces the atmosphere of Mars. Scientists come to the Arc Jet Complex at the Ames Research Centre in California to test heat shield materials.
In the above image, hot gas blasts through a half-metre-wide nozzle on the left, roasting an umbrella-shaped section of a heat shield at temperatures higher than 1,500°C. The bluish streaks flowing from its surface are generated by a resin layer that was applied to protect the craft.
After entering the red planet’s atmosphere, NASA’s Mars landers deploy giant parachutes to slow their descent to the surface. These parachutes are tested in the world’s largest wind tunnel at NASA’s Ames Research Centre. The tunnel is large enough to house a Boeing 737 and can generate hurricane-force wind speeds of up to 190 kilometres per hour. As the ‘wind’ blows, parachutes are fired from a mortar mounted high up in the wind tunnel on struts.
Parachutes have helped NASA safely land rovers weighing up to one tonne on to the surface of Mars. But NASA estimates sending humans and all their supplies on Mars will involve landing at least 10 times that weight. The space agency is researching sophisticated thrusters to replace parachutes in order to slow the rate of descent.
This is the space simulator at NASA’s Jet Propulsion Laboratory in California – a souped-up tanning bed that operates at bone-chilling temperatures. High-powered xenon lamps mimic sunlight, similar in intensity to that found on Mars. The Curiosity rover spent time in this chamber before touching down on Mars. Here, scientists are getting ready to test a vessel that will contain a Mars rover.
NASA doesn’t only test its hardware when planning a trip to Mars. The isolated slopes of Hawaii’s Mauna Loa volcano are the site of the Hawaii Space Exploration Analog and Simulation (HI-SEAS) testing facility. It examines the possible impact of living on Mars on the human mind.
In August 2015 a six-member crew entered an 11-metre wide dome for the experiment’s fourth iteration. They will stay for a year, carrying out experiments and maintenance. To communicate with family or read the news, they wait for a 20-minute delayed internet connection. To leave the habitat for their rocky surroundings, they have to suit up. It’s the full dress rehearsal for landing humans on Mars.
“We’re doing this in much the same way that people practice for track meets, debates and dance-offs,” crew member Sheyna Gifford wrote in her blog, two months into her 12-month stay. “It’s a little bit weird, but it’s also necessary to win the game, to finish the race, to get to Mars, for the show to go on.”