ENGINEERS AT UCD have been contracted by the European Space Agency to find new ways to reduce vibrations during lift-off in launcher designs.
The €250,000 contract will see the engineers design a “control algorithm”.
It will tell the launcher’s rocket engines and thrusters how they should most effectively be fired and controlled to absorb vibrations on their journey out of the Earth’s atmosphere and into space.
Too much vibration can damage the launcher’s structure and reduces “payload comfort”.
Reducing vibrations also helps to maintain the finely calculated trajectory of a launcher from lift-off into orbit.
Any departure from this course must be corrected, usually by steering the rocket motors, but this reduces the main thrust forward and so consumes more fuel.
Dr William O’Connor from the UCD School of Mechanical and Materials Engineering will lead the research, he said:
Keeping launchers on course when immensely powerful engines are violently shaking the structure is a complex problem.
“This is made even more complex when you consider that there are tonnes of liquid fuel like liquid hydrogen and oxygen sloshing around inside a relatively delicate structure.”
To lift-off, overcome the Earth’s gravity, and enter orbit, launchers must quickly reach a speed of 28,000 km/h from a standstill.
This requires an immense amount of fuel. They also need enough additional propellant to complete their mission.
At lift-off, about 90% of the weight of the launcher is fuel.
About 90% of the thrust coming from burning the fuel is used just to lift the fuel itself.
All the other weight, including the launcher structure, rocket motors, control systems, communication systems and of course the precious payload, must fit into the remaining 10%.
“The weight calculations are precise and literally every gram counts. If the ratio of thrust to weight from the chemicals in the fuel was a few percent lower, we would be stuck on Earth,” explains Dr O’Connor.
With designs tending towards lighter and lighter structures, launchers are becoming even more prone to vibrations and oscillations.
Our work aims to design more stable launchers, giving improved performance and a smoother ride than is currently possible.
Dr David McKeown is a partner on the research also from University College Dublin. He said: “Ultimately, it is all about safely delivering the payload into space with the most precision and minimum fuel consumption.”
Enterprise Ireland (EI) coordinates the participation of Irish companies and research teams in ESA programmes.
Dr Bryan Rodgers, Enterprise Ireland, said:
The space sector is of growing importance for Irish industry, with a growing number of Irish companies playing active roles in a range of space activities.
“This project on the control of future launchers is an important new addition to this work, with potential for commercial spin-out of the research, and I congratulate Dr O’Connor and Dr McKeown on winning this ESA contract.”
The research group at University College Dublin has previously worked on the control of large x-ray telescopes and a light flexible robot arm concept for an ESA Mars rover mission.
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