The ESA wants to solve a crucial puzzle: What really happens when accidents occur in orbit?
A model image of a collision with a satellite that generates debris. Photo credits: ESA / ID & Sense / ONiRiXEL
The European Space Agency (ESA) launches a new research project to study satellite collisions in space
"We want to understand what happens when two satellites collide," said Tiziana Cardone , an ESA site manager will lead the project on Tuesday. "So far, many assumptions have been made about how the very high collision energy would disappear, but we do not have a solid understanding of the physics involved."
Space junk is a real issue for future space missions The environment outside the earth is becoming increasingly crowded. Scientists have so far only seen four events where satellites have collided so far, and these collisions, plus 60 years of orbital launches, have left behind more than 500,000 pieces of flotsam that clogs space around the earth.
It increases the likelihood of space debris entering a spacecraft. These collisions are likely to leave rubble and cause even more trash.
Possibly this could cause a runaway chain reaction of collisions and debris, known as the Kessler effect, named after former NASA scientist Donald Kessler, who could destroy anything in the near-Earth orbit and fragments that are at thousands of miles per Rush around the planet and destroy everything that is on their way.
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The satellite collision occurred in 1991, when the Russian space probe Cosmos was hit in 1934 by a piece of older Cosmos 926 hardware. Five years later, the second incident between the French satellite Cerise and a part of the Ariane 4 rocket.
The third was in 2005, when an American satellite was hit by a Chinese missile and the fourth in 2009 between an Iridium satellite and the Cosmos 2251 from Russia.
It is obviously counterproductive to bubble in orbit, which is why the researchers have to concentrate on simulations instead. These are operated by the Fraunhofer Institute for Short-Term Dynamics, a materials science laboratory in Germany, and the Center for Studies and Activities for Space at the University of Padua in Italy.
"Of the four known collisions, only one was done in the way we expected, with both satellites crashing catastrophically and creating debris clouds," said Holger Krag, a researcher at ESA's Space Debris Office.
"The others were quite different, so something is missing our image, and by doing many different collision variants, we hope to understand what happened in the actual collisions to substantiate our modeling."
Numerical simulations model that Spacecraft as a "finite element grid", a common way to create predictive simulations of objects under stress. The material is broken down into smaller parts, called elements, which are converted into particle clouds upon collision of the satellite.
Another simulation method involves satellites that are composed of many different parts, such as plates, fuel tanks and solar energy arrays and payload. During a collision, the physical connections that hold these parts together are broken and fragmented.
Researchers can use and modify a library of past crash events and data to keep track of how satellites behave when they crash into one another. After these simulations, researchers will conduct hands-on experiments to smash satellites on a 500 kg scale.
"We need to have this understanding because we are currently working on expensive depletion strategies based on our understanding of debris, and we project the development of the debris environment to be 200 years ahead," added Krag. ®
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