As my arms rose above my head and my feet left the ground, I thought to myself: "?!?!"
This October, I left the comfortable embrace of Earth's gravity, taking to the skies aboard a "zero-gravity flight." I embarked on a plane ride aboard the Zero Gravity Corporation's (Zero-G) "G-Force One," a customized Boeing 727 airplane that flies passengers in a series of specially designed parabolas, or arc motions, to create weightlessness, simulating zero gravity, lunar gravity and Martian gravity in the cabin.
First: how does it work?
Think of the airplane like the cars of a rollercoaster, going up and over steep inclines and then plummeting down, only to come back up and climb another hill. But, instead of metal coaster tracks, the airplane goes up and over carefully planned-out parabolas in a slice of sky away from other planes for safety.
And, just as you might rise out of your seat going over the top of a rollercoaster's peak, as you crest over each parabola in the plane, your body lifts into the air. But, while technically you're in freefall, you actually float around the craft.
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Additionally, as you round out the bottom of the parabolas, you feel increased gravity — about 1.8 g's, or gravitational forces. (Earth's "normal" gravitational pull at the planet's surface is 1 g.) Now, depending on which of the 15 parabolas the plane is currently flying on, you either feel simulated zero gravity and float weightlessly or you feel simulated lunar gravity or Martian gravity.
So, what does it actually feel like?
Getting to the point: it feels nothing like I could have ever possibly imagined. It's the kind of feeling you can't anticipate, but once you've had the experience, the feeling is impossible to shake. Even while writing this, I keep finding my head spinning and my mind drifting off, back to the G-Force One cabin.
Now, I have seen countless videos of people floating weightlessly aboardG-Force One and thought that I had at least a pretty good rough idea of what was to come as I boarded the helicopter to the airport. (We all went in helicopters, which only added to the excitement and insanity of it all.)
Boarding the plane, my heart was pounding out of my chest with anticipation, beyond eager to jump head-first into this bucket-list item. I was a bit nervous that the flight might make me nauseated (and we all had "barf bags" secured in our flight suit pockets just in case), but since most people who take this flight don't get sick, I wasn't too worried.
After a short flight into the slice of sky where we would begin the parabolas, we all left our seats and walked forward into the main part of the cabin while wearing masks (Zero-G has changed its operations to include a number of COVID-19 safety precautions). The walls, floor and ceiling all were heavily padded for safe floating, and we all went to find our own space on the floor to lie down as we would soon feel the "heavy" 1.8 g's before lifting up on the first parabola — a lunar parabola simulating gravity on the moon's surface.
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The increased gravity wasn't uncomfortable; in fact, it felt kind of comforting being pushed against the bottom of the plane — like a gravitational weighted blanket. But before I knew it, we were flying over the crest, and I felt the ground give way.
What I expected to feel was the sensation of floating. From watching Zero-G flyers float on the plane to seeing videos of countless astronauts floating in space, it seemed reasonable to assume that what looked like floating might, well, feel a bit like floating. But instead, it was a sensation entirely its own.
What I realized pretty much immediately is that, as a human, my brain has been hard-wired to function with Earth's gravity, and I've gotten pretty used to Earth's gravity in my years on this planet. So, when it was taken away and I got my first taste of lunar gravity, my brain didn't know what to make of it. It was so amazingly, incredibly bizarre I might even liken it to a psychedelic experience.
In fact, I was so disoriented that it took me a minute to adjust my eyes to try and see straight as I stood up and my arms flew instantly above my head. I knew that with less gravity, every tiny action would merit a much bigger physical response, but actually experiencing it is completely wild! I barely moved and yet I was catapulting to the (padded) ceiling in absolute disbelief of the myriad of sensations rushing through me.
As soon as I had just begun to wrap my head around what was happening, we were nearing the bottom of the parabola and I lay back down on the cabin floor for the next round of 1.8 g's and my next moments in lunar gravity.
One really special part of experiencing lunar gravity, I found, was that I suddenly felt a little bit closer to the Apollo astronauts bunny-hopping across the lunar surface. As someone who grew up in utter awe of NASA's early, pioneering astronauts and the incredible journeys they took, feeling what those bouncing, awkward steps on the moon may have felt like was beyond words.
Mesmerized like a kid at Disney World for the first time, staring at Cinderella's castle, I continued to float through lunar gravity, Martian gravity and, finally, total weightlessness. When we crested over the top of the first "zero gravity" weightless parabola, I lifted right off of the ground, bewildered — my senses somehow even more confused and distorted than before.
Flight coach Ray Cronise, an author and scientist who served as an assistant mission scientist on four Spacelab missions during his 15-year career at NASA, helped to guide me and other flyers through the day. As my feet left the ground, he tossed me a colorful "koosh ball"l so I could see it floating weightlessly and experience the absolute magic of manipulating objects without gravity. I tried to catch it and, again a bit clumsy as I adjusted, caught it while tumbling backward head over heels (literally). Trying desperately not to bump into the others who were also getting used to it all, I made my best effort to get rightside-up again, experiencing my limbs and their movement without gravity for the first time.
At this point, the up-and-down motion of the plane and the overall sensory overload was starting to catch up to me, and I began feeling just a bit queasy. Upon lying back down to prepare for the next round of weightlessness, I realized that I might be getting sick on this flight after all. As the gravity pushed heavily against me, I stared straight ahead, hoping that if I kept my gaze focused on a single point the nausea would subside.
I kept my eyes locked, desperately, on a small knob on the ceiling, hoping that this focused stare might right the chaos that my brain was working feverishly to make sense of. But, alas, as gravity once again dissipated and I floated back upward, I saw Cronise floating over to me. As someone who's flown countless times, he knew the instant that I wasn't feeling well and he escorted me into a buckled seat in the back of the plane so I could try and catch my breath (and catch...well...you know).
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Unfortunately, I wasn't able to make a miraculous comeback, and both my flying partner and I ended up spending the last portion of the flight buckled into seats in the back, clutching our barf bags tightly. While disgusting and unpleasant as puking while weightless is, it was a quick and effective lesson in fluid dynamics, giving me a firsthand glimpse into how liquids behave when no longer acting in accordance with Earth's gravity.
Luckily, we were the only ones on the entire flight to get sick at all — I chalk it up to not taking any kind of anti-nausea medication before the flight (not even the most basic over-the-counter Dramamine). So, at the very least, I know the mistake I will not make if I ever have the opportunity to go weightless again.
Landing back on Earth and making my way home was a blur as I both attempted to settle my stomach and came to terms with the unbelievable day I'd just had. But, little did I know, the ride wasn't quite over. As I lay my head down to go sleep that night, I found myself instantly transported to the belly of the plane; lying back flat against the cabin, pressed down by the 1.8 g-forces, awaiting the next round of weightlessness.
For just that night, every time I'd close my eyes, I would find myself feeling that heavy gravity once again. I'd liken it to drifting off to sleep at night after spending the entire day floating in the ocean and still seeming to feel the rocking waves of the sea. But, instead of the ocean's waves, I fell asleep while feeling the heavy burden of gravity, only for it to lift from my chest, lifting me with it, over and over again.
Email Chelsea Gohd at firstname.lastname@example.org or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.