First-Hand Look: One Family's Unforgettable Zero Gravity Holiday
The Stern family of Colorado float in weightlessness during a Fourth of July holiday flight aboard a Zero Gravity Corporation aircraft on July 4, 2010.
Credit: Steve Boxall/Zero-G

Like many American families across the country, the Stern family of Colorado celebrated the Fourth of July holiday together on Sunday. But instead of a traditional barbecue or picnic, the family took to the skies for a novel weightless daytrip on a Zero Gravity Corporation (Zero-G) aircraft.

Here, journalist and eldest Stern daughter Sarah Stern describes the experience of the July 4th trip, which was arranged as part of a project led by her father ? planetary scientist Alan Stern ? investigating the scientific uses of zero gravity and suborbital spaceflights at the Southwest Research Institute:

Countdown to takeoff

I woke up to hear my dad?s muffled voice saying ?Welcome to Space Day? on the morning of the Fourth of July. My family and I were about to experience zero gravity, what many have labeled the ?gateway drug? for space tourism.

We began bright and early by meeting for Zero-G orientation in a conference room in a Hyatt hotel in Reston, Va. We were given flight suits with upside down nametags so that we could tell who was who during our floating experience. Once you have completed your first flight aboard G-Force One, you may turn your nametag around to show that you are no longer a first-time flier.

We were placed in a group with several Australian high school students who came to America to fly with their physics teacher and experience weightlessness. Along with them, we met passengers who flew to Washington D.C. all the way from Ireland and Texas. 

We also met Richard Garriott, an entrepreneur who spent time at the International Space Station, and was celebrating his birthday by making yet another Zero-G flight.

Unfortunately, we were unaware that we were not allowed to bring our own experiments onboard without prior permission, so we ended up having to leave our materials behind before we arrived at Dulles International Airport for our departure. 

We boarded the flight, which smelled strongly of rubber, and had about 40 seats in the back of the plane.  In front of the passenger seats, there was a large padded room dubbed the "floating lounge." 

Space Adventures, which owns Zero-G, had FAA-approved flight attendants who gave the exact same speech as they do aboard normal flights, though with a bit more gusto than usual. Their job happens to have a few more perks than the typical flight attendant, who is relegated to delivering half cans of soda midflight rather than simulating modern spaceflight.

Experiencing moon and Mars gravity

Once we were shoe-less and at cruising altitude, we were instructed to lie on the floor in the floating lounge and stare at the ceiling with our feet facing the back of the plane. As we climbed in altitude while lying down, the force of gravity felt strong and similar to being pulled toward the floor by a huge magnet.

I felt the skin on my face peel back slightly as we edged into our first parabola. We eased into weightless by starting with Mars gravity, which is about one-third of Earth?s gravity. After being pulled to the floor, there was a brief second before we could feel the plane dropping and then we began to float briefly.

Next, we cruised into lunar gravity, which is about one-sixth of Earth?s gravity. With both Martian and lunar gravity, you are not entirely weightless, though doing pushups and jumping around is much easier to do, as if you were on a trampoline. 

Zero-G uses incremental weightlessness in order to decrease the disorientation once you begin to experience zero gravity. Soon after we began to feel slightly lighter, we heard the command ?feet down, coming out,? which ordered us to lay down with our feet facing the back of the plane. Then we began the 12 zero gravity parabolas, which was far less than the 40 to 80 parabolas done in NASA?s K-Bird aircraft once used for weightless flights.

Weightless at last

After we glided into the parabola, the pressure of gravity suddenly decreased as the passengers floated magically up toward the ceiling of the plane. 

Experiencing zero gravity is a disorienting feeling because the loss of muscular control is both exhilarating and discomforting. Throughout your entire existence on Earth, you have had the usage of your muscles to move around. 

Once you are weightless, your movement is suddenly uncontrollable. You collide into walls and people and the only way to move to another area is to push off from the padded walls of the cabin lightly.

As I looked down the cabin, there were about 40 of us laughing and spinning around uncontrollably, while one photographer glided from edge to edge to capture the moment. 

After doing the first few parabolas, you learn how to be more agile with your movements. Although you cannot really control them, you can curl your body into a defensive posture and avoid flailing limbs in order to minimize injury. 

During our first zero gravity parabola, my mother was accidentally drop-kicked in the stomach, which knocked the wind out of her for a few minutes. Once everyone got their bearings and was getting used to entering in and out of parabolas, the real fun began.

My dad was able to bring a small paper airplane on to the flight, which flew up and backward as we exited each parabola. The passengers spent several of the parabolas trying to catch floating M & Ms and droplets of water in their mouths. 

By the time we got to the last few parabolas, I felt incredibly nauseous. Luckily, my mission was accomplished: I was able to avoid vomiting, though one other passenger was sick during the flight.

After exiting the final parabola, we watched the candy and the water hit the floor of the cabin and everyone returned to their seats. Once the flight was over, we were told by Garriott that the ?experience is not merely a simulation of what it is like to float away in space, it is identical.?

Faces across the room lit up, awestruck at the possibility that we could experience what it is like to be an astronaut on an otherworldly vacation that we will never forget.

The Zero Gravity Corporation offers weightless flights from airports in Las Vegas, Cape Canaveral, Fla., and Titusville, Fla., with occasional flights from Seattle, Los Angeles and New York. Tickets are typically $4,950 per person, though children are 50 percent off with a full-price ticket this summer, Space Adventures officials said.

Sarah Stern is the editor of the political blog New Era News, oldest daughter of planetary scientist Alan Stern and a freelance writer living in Boulder, Colo. This article was written for SPACE.com.