New era of launching astronauts trades in wings for capsule
Vehicle for upcoming NASA, SpaceX liftoff eschews shuttle for a simpler, safer design
Norm Knight started his NASA career in the ’90s with the space shuttle, impressed by the engineering marvel that launched like a rocket, hauled space station parts like a truck and then landed like a glider.
When space shuttle Atlantis touched down for the last time on July 21, 2011, Knight was on Houston’s mission control management team overseeing that landing. Nine years later, he’s helping with the
May 27 liftoff where NASA and SpaceX will resume astronaut launches from Florida. But this time, the vehicle will be reminiscent of the compact Apollo capsule that inspired his youth rather than the massive shuttle that nurtured his career.
“It was sad to see the shuttle retired,” he said. “It was a winged glider coming home that was like no other.”
Yet he’s excited for the SpaceX launch. NASA has spent years working with SpaceX, founded by billionaire Elon Musk, and Boeing to develop vehicles that could ferry astronauts to the International Space Station. The government agency provided funding and expertise, but the companies designed the spacecraft, which they own and operate. NASA will buy seats as a customer.
Compact capsules are simpler and faster to design than the bulky shuttle orbiter, which was 122 feet long with a 78-foot wingspan. A capsule’s placement on top of the rocket, rather than alongside it like the shuttle, can help keep astronauts safe.
Still, Knight said it was difficult watching the shuttle retire after fly
ing 30 years and 135 missions. NASA was suddenly dependent on Russia for reaching the International Space Station. And around that same time, President Barack Obama canceled the agency’s prior moon mission, the Constellation Program, where Knight and others had placed their post-shuttle hopes.
“That was a very hard time at NASA,” Knight said. “It really left the agency in a lot of turmoil relative to, ‘What are we doing? What is NASA’s role now?’ ”
But he sees a vision again. The launch of the SpaceX Falcon 9 rocket and Crew Dragon spacecraft, the final major test before SpaceX receives NASA certification for more regular flights to the space station, is a milestone for NASA collaboration with the private sector. That will be crucial in the agency’s new moon program, Artemis — NASA plans to buy seats on vehicles that will lower astronauts to the moon.
More leeway
NASA’s Commercial Crew Program, established as a standalone program on April 5, 2011, takes a very different approach from the Space Shuttle Program where NASA made all the design decisions and then owned and operated the vehicles.
NASA would give its contractors 10,000 to 12,000 requirements for a shuttle’s design. These requirements ranged from the ability to reach a certain orbit to how much stainless steel was included in bolts, said Phil McAlister, director of commercial spaceflight development at NASA headquarters.
For Commercial Crew, NASA had only 300 requirements. And they were mostly related to safety, such as an abort system to carry the spacecraft away from the rocket should a problem occur during launch and a statistical calculation that placed loss of crew at no more than 1 in every 270 flights.
NASA did not care if the Commercial Crew companies proposed a winged vehicle or a capsule, as long as the system was safe, reliable and cost effective. Sierra Nevada Corp., one of the final three contenders, proposed a winged vehicle.
McAlister said the companies’ entire systems were evaluated, and the Sierra Nevada proposal “was very strong.” Still, wings did factor into the decision. “Both Boeing and SpaceX use a capsule spacecraft, which is a lower complexity design than (Sierra Nevada’s) winged spacecraft,” according to a 2014 document explaining the Commercial Crew selection, “and therefore minimizes the work and time required to complete development.”
NASA chose SpaceX and Boeing in September 2014, and the two companies have contracts and Space Act Agreements worth $8 billion; NASA has thus far provided just under $6 billion to help with development.
Keeping it simple
Boeing and the companies it’s acquired over the years have experience building capsules and space shuttles. It picked the capsule design for the CST-100 Starliner.
“It was a shorter road to get that fully developed and in use,” Boeing spokesman Steven Siceloff said, “and it met NASA’s needs.”
SpaceX did not respond to requests for comment. But during a May 1 news conference Benji Reed, SpaceX director of crew mission management, said the Crew Dragon was built on decades of capsule heritage as well as the company’s uncrewed cargo capsule, which began delivering supplies to the space station in 2012.
Phil Smith, a space industry analyst at Bryce Space and Technology, said capsules are structurally simpler than winged spacecraft when designing and modeling how a vehicle will behave while landing. A capsule comes in like a cannonball. Fixed wings, however, act one way at a certain speed or air density and then a completely different way at other speeds or air densities, presenting design challenges.
“Flying a winged vehicle back from orbit is more complicated than bringing back a capsule,” said Jeffrey Hoffman, a retired shuttle astronaut and professor in the Department of Aeronautics and Astronautics at Massachusetts Institute of
Technology.
But winged vehicles haven’t disappeared. Sierra Nevada Corp. is still developing its Dream Chaser spaceplane, retooling it to deliver cargo rather than people to the International Space Station. Steve Lindsey, a former space shuttle commander and the senior vice president of strategy at Sierra Nevada, said the Dream Chaser’s ability to land on airport runways gives it global reach. And the force of gravity during this landing is gentler than in a capsule that lands in the ocean or on airbags in the desert. Some experiments, such as growing protein crystals, are delicate and sent into space specifically for its lesser gravity.
Ultimately, Sierra Nevada is still working toward flying people.
Virgin Galactic is likewise planning to use a winged vehicle for suborbital space tourism. WhiteKnightTwo is a custom-built, dualfuselage jet aircraft and attached to its belly is the winged SpaceShipTwo, where passengers will sit. It has launched its pilots and an employee into weightlessness, but it has not yet flown paying customers.
Space travel is risky, with two space shuttle accidents killing 14 people, but designs using capsules can have features to help minimize risk, especially during launch, said Scott Hubbard, adjunct professor in Stanford University’s Department of Aeronautics and Astronautics and former director of NASA’s Ames Research Center.
Space shuttle Columbia broke apart during reentry in 2003, but the damage that caused this accident occurred during launch. A large piece of insulating foam fell off its external tank, which held fuel for the main engines, and punctured a hole in the wing of the space shuttle’s orbiter. This caused the vehicle to overheat during reentry.
Placing a capsule on top of the rocket prevents it from being pummeled by launch debris.
Space shuttle Challenger broke apart 73 seconds after launch in 1986. One of its solid rocket boosters had a leak in the O-ring that caused an explosion and destroyed the orbiter vehicle. The orbiter could not escape the boosters during this part of the ascent.
“You could lose almost one of anything and you could get back safely,” Hoffman said. “Obviously, they didn’t plan for a major explosion or failure of the solid rocket booster.”
For Commercial Crew, NASA required an ability to remove crew from dangerous launch situations. SpaceX, Boeing and Sierra Nevada included this in their proposals.
SpaceX and Boeing are using a pusher system with specific abort motors to push the crew up and away from the rocket. It’s a feature astronaut Doug Hurley, who will be one of two astronauts on the flight test, addressed during a news conference.
“It’s a pretty safe design,” he said. “It gives us abort capability from the pad all the way up into space, which the space shuttle, I think has been well publicized, didn’t have that capability in all phases.”
Hubbard, who helped investigate the Columbia accident, felt the space shuttle was retired partly due to its safety concerns. He said the vehicle was so complex that there could have been more failures NASA was lucky to not encounter.
A new era
Not everyone thought this was a fair opinion. Knight, for instance, felt that NASA was managing the shuttle’s risks.
Promoted from chief flight director to the deputy director of flight operations in 2018, Knight will be at Kennedy Space Center on May 27 representing NASA’s astronauts and flight operations by giving a go (or no-go) to the agency’s launch manager. Both NASA and SpaceX must give the green light before liftoff.
After the launch, Knight will return to Houston to assist with other portions of the flight test, which is being run by teams in Florida, Houston and the SpaceX headquarters in California. Astronauts Hurley and Bob Behnken could spend between 30 days and 119 days on the space station before splashing down in the Atlantic Ocean.
Knight hopes this is part of a longer road NASA is paving into space, partnering with commercial companies to bring the rest of us along.
“I’m excited to see this thing lift off,” Knight said. “It’s going to be a bright shining star for our future in space. It’s really the beginning of a new era.”