This milestone was so recent that many can still remember a time before it – and despite our incredible advances since that October evening in 1957, human beings' knowledge of space is still fresh in its infancy. We are continuously struggling with hazards to do with Earth's orbital atmosphere, radiation, and space junk, let alone that associated with other planets.
One of the issues scientists face when it comes to close-to-home space travel is broad-spectrum background radiation. For example, the spectral flux of electrons, protons and ions in Earths Van-Allen belts have the ability to affect on-board electronics, and until recently, we have not been able to create effective laboratory simulations of this type of radiation for testing purposes.
However, in January 2017, Scientists from the University of Strathclyde in collaboration with the University of Düsseldorf and the CLF, managed to re-create Van-Allen belt type broadband radiation, which was then successfully used to test the hardiness of space instruments. Based on NASA's AE8/AP8 and AE9/AP9 models, Prof. Bernard Hidding and his team did experiments on Düsseldorf's laser, Arcturus, and the CLF's laser, Vulcan PW, using peak laser powers in the P ~ 150 TW to PW range to produce an electron and proton flux similar to that which surrounds the Earth.
This was achieved by compressing each laser to spot sizes of the μm2 range, and pulse durations as short as 20 femtoseconds, before shooting them onto thin metal foil targets. This created interaction intensities of I ≈ 1018–1020 W cm−2.
“You need a very powerful laser to generate the kind of energies of particles we see in space," David Carroll stated, who was one of the link scientists for Vulcan laser, “Unlike existing techniques that have been used to do similar testing, we have the capability to simultaneously mimic the broad range of energies and types of radiation found in space."
Previous to this experiment, electron flux from the outer Van-Allen belt and proton flux from the inner Van-Allen belt have been shown to significantly degrade optocoupler performance, making the need for state-of-the-art testing procedures vital. This work produces broadband inner and outer Van-Allen belt conditions that can “systematically characterise realistic degradation of space electronics", disclosing for the first time that laser-plasma-accelerators can be used for reliable space radiation testing.
“This means you could test complex electronics, such as those used in manned space travel or on satellites, as these are the kinds of thing which are vulnerable to interference and damage from charged particles. It's hoped that these test facilities will not only make space travel safer, but also less expensive," link scientist, James Green, said about the results.
These results are particularly important now that we are beginning to travel further and further out into our solar system, and while the Earth's magnetic fields may be a problem for space instruments, the magnetic fields of Neptune, Uranus, Saturn and Jupiter are far more challenging.
If we are to explore such things as the prospect of habitable zones on Io and Europa, we must insure the instruments we send can survive the harsh radiation environment that surrounds Jupiter. For reasons such as this, this research has been of great scientific priory and its success will hopefully lead to new gains in space travel technology.
1: Hidding, B. et al. Laser-plasma-based Space Radiation Reproduction in the Laboratory. Sci. Rep. 7, 42354; doi: 10.1038/srep42354 (2017).
For more information, please go to: https://www.nature.com/articles/srep42354