For 10 minutes the first flight by an aircraft, powered fully by solid hydrogen, has stayed in the air. It is an experimental drone and runs on pellets that emit only water vapour when they burn. The fuel cell is also three times as light as a comparable lithium battery. 

Previously, large tanks of liquid hydrogen kept at super-low temperatures were needed to power hydrogen flight.  But the tanks were too big to be practical. Storing hydrogen as a pressurised gas is also inefficient. The new system uses 100 solid pellets packed into a cartridge. The 1-centimetre-long pellets are made from a chemical compound that produces a steady stream of hydrogen as it is gently heated. This gas is converted into electricity in a fuel cell that runs the drone’s rotor. The inclusion of a polymer stops the compound melting and helps it release hydrogen at a lower temperature. Unlike with a battery, if you put in twice as much fuel you can go twice as far. It is cleaner and because the drone’s propeller is its only moving part, it is also not susceptible to carburettor icing that can prevent petrol drones from operating in extreme cold. (Niall Firth, New Scientist)

Amid all the political turmoil and violence in the world, good news that could have dramatic effects on the environment in the next twenty yesrs keep emerging, offering hope for staving off some of the most dire predictions on climate change. This is just one instance; tomorrow another.