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Planetary News: Human Spaceflight (2007)

Stephen Hawking Flies into Zero-G and "Tastes" Space

Click to enlarge > Stephen Hawking goes "zero" Renowned British theoretical physicist Stephen Hawking took to the skies above Florida yesterday and experienced zero-gravity onboard a commercial jet especially converted for weightless flights. The Zero Gravity Corporation first began offering weightless flights to the public in 2004. Credit: Zero Gravity Corp.

British theoretical physicist Stephen Hawking – whose groundbreaking work on black holes and the origins of the universe has rewritten physics – floated free of his wheelchair in zero-gravity yesterday. Flying onboard a commercial 727 jet especially converted for weightless flights, he experienced for the first time what astronauts-in-training experience on NASA's KC-135, better known as the "Vomit Comet."

Hawking, 65, perhaps the most renowned theoretical physicist of his time, has long suffered from a motor neuron disorder called amyotrophic lateral sclerosis (ALS), better known as Lou Gehrig's disease. Unable to move his hands and legs, he has been wheelchair bound for nearly four decades. In the mid-1980s, he also lost his ability to speak naturally after a tracheotomy following a bad bout with pneumonia.

As a result, Hawking, who is the Lucasian Professor of Mathematics at the University of Cambridge in England, communicates by making small facial expressions, using the muscles around his eyes, eyebrows, cheek and mouth, raising an eyebrow, for example, to signal "yes." Technology has allowed him to communicate more extensively through a computer that talks for him in a synthesized voice while he chooses words on the screen through an infrared sensor on a headpiece that detects motion in his cheek. That voice has resounded -- as definitively Hawking's -- through pop culture as well as scientific circles and he has defied all ALS odds. But he lives immobilized in a body debilitated by the irreversible neuromuscular disorder.

Yesterday, Hawking escaped the confines of his illness for 4 minutes and experienced a freedom unlike any he's ever known, becoming the first person with a disability to experience a zero-g flight on this commercial airline.

Before taking off over the Atlantic Ocean, Hawking acknowledged that experiencing weightlessness even for a few seconds would be a welcome change from life in the wheelchair. "The chance to float free in zero-g will be wonderful," he said through his computer voice synthesizer during a pre-flight news conference. "I want to demonstrate to the public that anybody can participate in this type of weightless experience."

Previously, the only way to experience zero-g was to snare a ride on NASA's "Vomit Comet," which of course wasn't and isn't likely unless you're an astronaut or lucky journalist. Now, with its G Force fleet of 727s, Zero Gravity Corporation has opened up the skies to the general public with parabolic flights over Florida and Nevada. These are the same type of flights used by NASA to train its astronauts and used by Ron Howard in the filming of Apollo 13.

The brainstorm of Peter H. Diamandis, who created the X Prize, and astronaut Byron K. Licthenberg, the first payload specialist on the space shuttle, Zero Gravity Corp (ZGC) began in the early 1990s. Once they chose the aircraft -- a Boeing 727 cargo plane -- and put it through a series of Federal Aviation Administration (FAA) test flights, they redesigned the interior, padding it for flyers' protection, and made some other technical changes under the guidance of the agency. The company conducted its first parabolic flights in 2000 for the filming of Matrix Reloaded, then worked with the FAA to complete the engineering and testing needed to achieve the safety requirements.

By 2004, ZGC had secured the needed FAA approval and began offering parabolic or weightless flights to the public. Since then, it has flown about 2,700 people on the Florida-based flights and just recently began offering flights out of Las Vegas.

Hawking, who was accompanied on his flight by physicians and nurses, announced the plans for this flight earlier this year at his 65th birthday celebration on January 8 in Cambridge, England. Beyond the fun of floating free, he is preparing for a sub-orbital spaceflight on Virgin Galactica, the "spaceline" offshoot of Virgin Airways, slated to begin launches in 2009. Virgin's founder, billionaire Richard Branson, said he will cover the $200,000 tab for the flight into space.

Although Hawking'scontributions to the fields of cosmology and quantum gravity are beyond the comprehension of most people, his popular efforts, wherein he discusses his own theories and musings and cosmology in general, have struck a chord in the mainstream. A Brief History of Time -- often referred to as the book everyone owns but no one understands -- stayed on the British Sunday Times bestseller list for a record-breaking 237 weeks and is an all-time bestseller. His more recent pop venture, The Universe in a Nutshell, is still topping charts all over the world.

Once ZGC's G Force jet reached its proper altitude, Hawking's assistants lifted him out of his seat and positioned him on his back in the front of the cabin for the first parabola or maneuver.

The feeling comes on slowly at first, moving from the legs to the stomach, chest, and finally -- as the emotional anticipation builds -- the head -- and -- voila – instant bliss permeates the brain. The body rises and within seconds -- zero-g --  weightlessness.

As Hawking floated free, unbound by wheelchair or the 1 gravity in which we live on Earth, the smile on his face was unmistakable. (Not surprisingly, he'd done his homework and took a motion sickness pill, just in case, prior to the flight.)

With the help of his assistants and Diamandis, ZGC's chairman, Hawking spun like gymnast, floated like an astronaut, and beamed like everyone who knows the joy of zero-g. Words cannot really describe the experience, because leaving the 1 gravity of Earth and feeling weightless is like nothing you will ever experience while on this planet.

The sense of weightlessness is actually artificial and is created when the plane is flown in parabolic arcs in the sky. Basically the jet flies up and down, kind of like it's following a Bell curve. Specially trained pilots fly these maneuvers between approximately 24,000 and 34,000 feet altitude. Each parabola takes 10 miles of airspace to perform and lasts approximately one minute from start to finish, offering up 30 - 45 seconds of reduced gravity in the midst of the maneuvers.

Initially the jet pulls up to approximately 45 degrees "nose high" and climbs to about 34,000 feet, then "pushes over" the top of the arc to reach into the zero-gravity segment of the parabolas. For the next 25 - 30 seconds everything in the plane is weightless. At approximately 30 degrees "nose low," a gentle "pull-out" is initiated. This allows the flyers about 20 seconds to get back down on the aircraft floor and in line with the vector of the aircraft. The force is slowly increased to about 1.8-g's during the pull-out until the aircraft reaches a flight altitude of 24,000 feet. That completes one parabola and the maneuver is then repeated.

It gets better: the type of gravity experienced can actually be changed to lunar gravity (1/6 Earth gravity) or Martian gravity (1/3 Earth gravity) as well as zero-g simply by altering the jet's "angle of attack" on the climb up.

Periods of 1.8-g's both precede and follow the periods of weightlessness -- and are critical to an enjoyable flight. If you are not properly positioned in line with the vector of the aircraft (facing front) during those periods, you risk airsickness and a bout with the bag in the back of the aircraft. And once you get sick, the party's over. For those who do their homework, pay attention to the flight director, and properly position themselves, however, "going zero" it is pure, sheer ecstasy.

The experience has been likened to that of a roller coaster, but that description doesn't cut it. Unlike the ride on a coaster, there is no feeling of weight, no feeling of force slamming you against the side of the coaster, and no feeling like your brain is going to explode or be ripped from your head. Rather, in search for a comparison, the weightlessness experienced in zero-g is more equivalent to the type of "free fall" experienced in skydiving minus the face-distorting on-rushing wind. But even that only inadequately describes what it's like.

Currently, ZGC is the only company approved by the FAA to conduct weightless flights for the public. On most flights, the thrill lasts for about 15 parabolas and costs about $3500 a pop, but yesterday the ticket fee was waived so that the expert on gravity could defy gravity.

About two hours after it took off yesterday, the ZGC's G Force returned to the Kennedy Space Center in Florida via one of the space shuttles runways. It had flown eight parabolas, giving Hawking a total of four minutes of weightlessness.

"It was amazing . . . I could have gone on and on," Hawking said after landing. "Space, here I come."

The smile recorded on the video and news cameras during his flight, however, said far more than words ever could.

The author flew aboard the maiden flight of Zero Gravity Corp's G Force One over the Pacific Ocean, along with Planetary Society Advisory Council member Buzz Aldrin and two-time space shuttle commander Kevin Kregel, on September 15, 2004.