Weightless: parabolic flight on an A310

I check that my feet are planted shoulder width apart and my knees are bent as the announcement for the start of the third parabola calls out 30 seconds. Then 20, 10, 5, 3, 2,1. Pull up! Immediately, I feel heavier—1.8 times heavier as the pilots pull the aircraft through 30 and 40 degrees to a 50 degrees nose up attitude.

The Zero G airline

Novespace was founded in 1986 as a subsidiary of the French space agency (CNES) to promote microgravity research using parabolic flights. Flights began with a Caravelle, but that was replaced with an Airbus A300 in 1995. In 2014 the current A310 was purchased from the German government after being used to transport the German Chancellor. Today’s microgravity research flights are operated by Novespace with partner organizations including CNES, the European Space Agency (ESA), and the German Aerospace Research Center — Space Agency (DLR).

The interior of the A310 has been heavily modified, but only small changes have been made to the flight deck. Except for the two accelerometers, the flight deck is the same as any A310. In the cabin, white padding and guide rails keep free-floating participants safe in the front three-quarters of the aircraft. The rear of the plane includes the original seats and is used for take off and landing.

The first timer

As soon as the seatbelt sign is turned off, scientists jump out of their seats to prepare their experiments. Time before the first parabola is short and every second of microgravity counts. Some must connect the electrodes attached to their skin to the computers in their rack, others power up their tiny, but powerful electro magnets, while others still are ensuring that the temperatures of their cell cultures are within range.

Dr. Katrin Stang, DLR’s Parabolic Flight Program manager, reminds me not to move my head in hypergravity. She wants me to experience the first parabola from my seat. She moves to the main cabin where the experiments are located and wraps one of the floor mounted safety straps around her leg to keep from floating away as the first parabola (parabola 0) begins.

I sit pressed in my seat, hypergravity pushing on me with 1.8g until the injection and then I float up in my seat as we go ballistic. Looking out the window I can see the wing of the A310 level off of then begin its free fall back toward the earth, pointing down at 20, then 30, and finally 42 degrees before gravity returns after 22 seconds of weightlessness.

For the next parabola, Stang tells me to loosen my seatbelt so that I can really feel the weightlessness. At injection I float up as far as my belt will allow, bouncing back down in my seat taking full advantage of Newton’s laws of motion.

Injection

Hold a ball in one hand and toss it to your other hand and you’ve just replicated parabolic flight in miniature. The ball begins its ballistic phase as it falls back to earth. The idea is the same with the A310, but instead of two hands and a ball you have two engines and an airframe. Injecting the aircraft into an arc of an orbit around the earth maximizes the time of weightlessness. By climbing first and then diving, instead of just flying level then diving, the time of weightlessness is doubled. As Jean-François Clervoy, former astronaut and chairman of Novepsace, puts it to me, “the principle of zero g flight is to throw the plane in the air and make it believe it is in vacuum.”

To fly a parabola takes 3 pilots working in concert. Two pilots sit in front of the control columns and a third sits in the center jump seat to manage the engines. When flying a parabola, one pilot is responsible for the pitch of the aircraft and the other for the roll. The pilot responsible for the roll of the aircraft actually has a modified control column in order to put as little pressure on the yoke as possible, allowing the pitch pilot to focus on the correct parabola timing.

From level flight, the pilots enter the parabola by pulling aft on the control column raising the nose of the A310 to +50 degrees within 21 seconds. At 24 seconds, the aircraft is injected into “orbit” and weightless begins for 22 seconds. During this time the pilots bring the nose of the aircraft down from +50 degrees to -42 degrees before pulling back once again for 26 seconds bringing the aircraft back to level flight.

There are a total of four pilots on board each flight, three working, one resting. Pilot Bertrand Rameau says switching after about 5 parabolas allows the pilots to stay fresh and not fatigue. Getting the timing of the parabola right, or as Rameau says, “listening to the music,“ is the most important thing for a successful flight.

Most of Novespace’s pilots come from test flight backgrounds, either civilian or military. They train extensively in a simulator to gain understanding on how the A310 will operate when flying a parabola and to train for any emergency procedures. Once simulator training is complete, they perform a series of test flights without passengers before being qualified to operate the Novespace A310 for scientific and commercial flights. Because Novespace only operates about 30 flights per year, the pilots hold other positions as well, some doing test flying, others running airline operations.

Research in microgravity

It’s parabola number seven and the Space Bike team is hard at work. Their test subject is connected to a battery of electrodes including a helmet designed to detect brain waves. The team’s goal during this flight campaign is to gain a better understanding of how the brain’s commands to the rest of the body are impacted by different levels of gravity. This research will help inform the training for astronauts as they move beyond earth orbit and into moon habitats and eventually landing and working on Mars.

The team from RWTH Aachen and ICARE-CNRS near the front of the aircraft is lighting things on fire. Their research investigates the properties of so-called “cool flames” in microgravity—important research to better understand under what conditions fuels will ignite in space and how the flames behave once ignited.

Another team from University of Bremen, ZARM, is testing space refueling. Their experiment on board the parabolic flights is being validated prior to inclusion on the International Space Station. Future spaceflight beyond earth orbit will need to take advantage of ship-to-ship refueling and understanding the properties of transfer between two tanks in microgravity is critical before any large-scale testing.

Getting the full flight experience

The combination of parabolas and a healthy amount of regular old turbulence on this flight mean that my body decides I should receive the full flight experience, including the use of air sick bag provided to each person on board. The onboard doctor checks on me, gives me a fresh bag, then floats away.

Thankfully the rest of the flight passes without further incident and after 31 parabolas we return to Bordeaux. Back on the ground it takes about 20 steps to realize two things: I’m exhausted and I want to fly again as soon as possible.

After the flight, all teams gather for debriefing. The flight crew reports how the flight went from their perspective and any necessary adjustments for the following day. The crew reports that due to the turbulence experienced during the flight over the Atlantic, the next flight day’s flight will likely take place over the Mediterranean. Then each scientific team reports what worked well on their experiments, what needs improvement, and any changes for future flights. Most report that everything went well, while a few will return to the aircraft in the afternoon to modify their experiments and prepare for the next flight.

Novespace continues to expand its cooperation with various space agencies as one of the few providers of parabolic flight campaigns and the only to offer such a large platform to scientists. They also offer public flights that help defray the costs of the scientific research flights, so if you’re keen to give it a go, its possible to enjoy weightlessness for yourself. As human spaceflight is revived in the coming years with missions to the moon and Mars, the Novespace A310 is poised to continue playing a crucial role in validating research here on earth.