It has been an exciting and busy summer for the European Space Agency, with development and testing of its new Ariane 6 launcher.

At Europe's spaceport in, French Guiana, a test model of the launcher's central core was assembled for the first time.

Ariane 6 is the first Ariane rocket to be assembled horizontally, which is simpler and less costly than more traditional vertical assembly. After assembly, the rocket was moved to its launchpad and placed upright in the massive mobile gantry for combined tests, to validate the compatibility between all components of the complete launch system.

Soon more testing will be done on Ariane 6's upper stage at a purpose-built DLR facility in Lampoldshausen, Germany.

For decades, scientists have been trying to solve a vexing problem regarding the weather in outer space: At unpredictable times, high-energy particles bombard the Earth and objects outside the Earth's atmosphere with radiation that can endanger the lives of astronauts and destroy satellites' electronic equipment. These flare-ups can even trigger showers of radiation strong enough to reach passengers in airplanes flying over the North Pole. Despite scientists' best efforts, a clear pattern of how and when flare-ups will occur has remained enduringly difficult to identify.

This week, in a paper in The Astrophysical Journal Letters, authors Luca Comisso and Lorenzo Sironi of Columbia's Department of Astronomy and the Astrophysics Laboratory, have used supercomputers to simulate when and how high-energy particles are born in turbulent environments like that on the atmosphere of the sun. This new research paves the way for more accurate predictions of when dangerous bursts of these particles will occur.

"This exciting new research will allow us to better predict the origin of solar energetic particles and improve forecasting models of space weather events, a key goal of NASA and other space agencies and governments around the globe," Comisso said.

More than half of the thousands of satellites in orbit are now defunct, and this accumulation of floating space debris has been described as a "fatal problem" for current and future space missions and human space travel.

An estimated 130 million objects smaller than 1cm and 34,000 larger than 10cm are traveling in orbit at speeds of thousands of kilometers per hour, according to the European Space Agency (ESA). A report presented at this year's European conference on space debris suggests the amount of space junk could increase fifty-fold by 2100.

While many fragments of space junk are small, they travel so fast their impact has enough energy to disable a satellite or cause significant damage to space stations.

Both the Hubble Telescope and the Solar Maximum Mission (SMM) satellites had coin-sized holes punched into them by flying debris and a mirror on Nasa's James Webb space telescope was damaged by micrometeoroids.

Most satellites were not designed with the end of their usefulness in mind.