Particle physics research

Aus ‘vomit comet’ is a big deal for zero gravity space research

Gail Islands, RMIT University

Last Saturday, a two-seater SIAI-Marchetti S.211 jet took off from Essendon Fields Airport in Melbourne with an expert aerobatic pilot at the controls and a briefcase full of science experiments in the passenger seat.


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Pilot Steve Gale took the jet on Australia’s first commercial ‘parabolic flight’, in which the plane flies along the path of a free-falling object, creating a short period of weightlessness for everyone and everything inside.

Parabolic flights are often a test for the weightless conditions of space. This was operated by Australian space company Beings Systems, which plans to perform 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 Leader of the RMIT Space Science Degree, I have been teaching these students for three years, preparing them for a career in the Australian space industry.

The experiments study the effect of weightlessness on plant growth, crystal growth, heat transfer, particle agglomeration, foams and magnetism.

RMIT University science payloads designed for parabolic flight. Gail Islands

Scientific phenomena behave differently in weightlessness than in laboratories on Earth. This is important for two main reasons.

First, weightlessness, 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 “purer” state and thus better understand it.

Second, microgravity platforms such as parabolic flights, sounding rockets, and drop towers provide testing facilities for equipment and science before it is sent into space.

Lab on an airplane: a mini ISS

Last Saturday’s flight was a success, with all six experiments recording a variety of data and images.

The plant experiment observed broccoli seedlings throughout the flight and found no adverse reactions to hyper or micro gravity.

Another experiment formed a crystal of sodium acetate trihydrate in microgravity, which grew much larger than its counterpart on the ground.

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Insulin crystals grown in standard gravity (left) are smaller than those grown in microgravity (right). Nasa

The largest weightlessness laboratory is of course the International Space Station (ISS), where studies of plant growth, crystal growth and physical science phenomena are commonplace. At any given time, 300 experiments are taking place on the ISS.

Turning a benchtop experiment into an autonomous science payload for space isn’t easy. Each must be rigorously tested before launch to ensure it will work once there, using parabolic flights or other test platforms.

Go ‘zero-g’

There is a common misconception that you have to go to space to experience microgravity. In fact, it is the free fall condition that makes things seem weightless and can be experienced here on Earth as well.

If you throw a ball at a friend, it will arc as it flies through the air. From the moment it leaves your hand, it’s in free fall – yes, even going up – and it’s the exact same arc the plane flies. Instead of a hand, it has a motor providing the “thrust” it needs to travel and fall through the air, tracing a parabolic arc as it goes.

Diagram showing the speed, acceleration and flight direction of an airplane in parabolic flight.
The flight path during the parabolic maneuver. Van Ombergen et al., Scientific Reports (2017)

Even the International Space Station experiences the same free fall as the bullet or the plane. The only difference for the ISS is that it has enough speed to “miss the ground” and keep moving forward. The combination of forward velocity and pull to Earth causes her to spin in circles, orbiting the planet.

Manned spaceflight

Parabolic flights in the United States and Europe take place every two or three months. During flights, researchers do science, companies test technologies, and astronauts receive training in preparation for space missions.

As a researcher at the European Space Agency and a former astronaut instructor, I am a veteran of five parabolic flight campaigns in Europe. I made more than 500 parabolas on board Novespace’s Airbus A300.

Although I never got sick on these flights, up to 25% of people on board vomit in zero g conditions. This is why they are sometimes called “vomit comets”.

Why now?

So why does Australia suddenly need parabolic flights? Since the establishment of the Australian Space Agency in 2018, several space projects have been funded, including a lunar rover, four Earth observation satellites and a spacesuit.

For these projects to succeed, all of their various systems and components will need to be tested. This is where parabolic flights come in.

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The plane flying over Melbourne (top left), with students (bottom left) and preparing for flight (right). systems of beings

As demand increases, Australian aircraft will also increase. Beings Systems intends to offer a larger aircraft – like a Lear jet – by 2023, so researchers and companies can test their gear, big and small, without leaving the country.

In addition to reading exciting scientific articles on the latest phenomena observed in microgravity, we will begin to see images of satellites testing the deployment of their antennas and of people putting on and taking off spacesuits aboard parabolic flights.

Gail Iles, Lecturer in Physics, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.