Gail Eales (opens in new tab)Senior Lecturer in Physics, RMIT University
On June 18, a two-seater SIAI-Marchetti S.211 took off from Melbourne’s Essendon Fields Airport with an experienced pilot at the controls and a box full of scientific experiments in the passenger seat.
Pilot Steve Gayle (opens in new tab) took the plane on Australia’s first commercial “parabolic flight”, where the plane flies in the path of a free-falling object, creating a brief period of weightlessness for everyone and everything inside.
Parabolic flights are often a test for zero gravity space conditions. This one was operated by the Australian Space Company Beings Systems (opens in new tab)which plans to operate regular commercial flights in the coming years.
As Australia’s space program begins to take off, flights like these will be in high demand.
What was on the plane?
The experiments on board the flight were small packages developed by space science students at RMIT University. As program manager of RMIT’s space science degree, I have taught these students for the past three years, preparing them for careers in the Australian space industry.
Experiments investigate the effect of zero gravity on plant growth, crystal growth, heat transfer, particle agglomeration, foams and magnetism.
Scientific phenomena behave differently in zero gravity than in laboratories The Earth. This is important for two main reasons.
First, zero gravity or “microgravity” provides a very “clean” environment in which to conduct experiments. By removing gravity from the system, we can study a phenomenon in a more “pure” state and thus understand it better.
Second, microgravity platforms such as parabolic troughs, sounding rockets, and drop towers provide test facilities for equipment and science before it is sent into space.
Laboratory in a plane: mini ISS
The flight was successful, with the six experiments recording various data and images.
The plant experiment monitored broccoli seedlings during flight and found no adverse reactions to hyper- or microgravity.
Another experiment formed a crystal of sodium acetate trihydrate in microgravity that grew much larger than its counterpart on earth.
The largest zero-gravity laboratory, of course, is International Space Station (ISS), where studies of plant growth, crystal growth, and physical science phenomena are commonplace. At any given moment, 300 experiments are being conducted on the ISS.
Turning a benchtop experiment into a stand-alone scientific payload for space is not easy. Each one must be rigorously tested before launch to make sure it will work once it gets there, using parabolic flights or other testing platforms.
Transition to zero speed
There is a common misconception that you have to go into space to experience microgravity. In fact, it is the state of free fall that makes things apparently weightless, and this can also be experienced here on Earth.
If you throw a ball to a friend, it creates a rainbow as it flies through the air. From the moment it leaves your hand, it’s in free fall—yes, even on the way up—and that’s the exact same arc the plane flies. Instead of an arm, it has a motor providing the “push” it needs to travel and fall through the air, tracing a parabolic arc as it goes.
Even the International Space Station experiences the same free fall as the ball or the airplane. The only difference for the ISS is that it has enough speed to “miss the ground” and move on. The combination of the forward speed and the attraction to Earth causes it to spin in circles, orbiting the planet.
Human space flight
Parabolic flights in the US and Europe take place every two or three months. During the flights, researchers conduct scientific research, companies test technologies, and astronauts receive training in preparation for spaceflight.
Blue skies, fuel in the tank, payloads loaded Marchetti flight ahead on a beautiful morning in Melbourne, Australia. @RMIT @beingssystems pic.twitter.com/X88SZldbqCJune 18, 2022
As a researcher at the European Space Agency and ex instructor cosmonaut (opens in new tab), I am a veteran of five parabolic flight campaigns in Europe. I have flown over 500 parabolas aboard a Novespace Airbus A300.
As long as I have never get sick on these flights (opens in new tab), up to 25% of people on board will vomit in zero gravity conditions. This is why they are sometimes called “vomit comets”.
So why does Australia need parabolic flights all of a sudden? Since the establishment of the Australian Space Agency in 2018, several space projects have received funding, including a moon rover (opens in new tab), four earth observation satellites (opens in new tab) and a space suit (opens in new tab).
For these projects to succeed, all of their various systems and components will need to be tested. That’s where parabolic flights come in.
As demand increases, so will Australian aircraft. Beings Systems plans to offer a larger aircraft — like a Lear jet — by 2023 so researchers and companies can test their equipment, big and small, without leaving the country.
In addition to reading exciting scientific papers about the latest phenomena observed in microgravity, we’ll start seeing footage of satellites testing the deployment of their antennas and people putting on and taking off spacesuits aboard parabolic flights.
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