The design of the regenerator causes the helium to expand and contract in a way that produces a powerful sound wave.

ECONOMIST: A more efficient way to make electricity in spacecraft

For them, it has been testing a new bit of technology - called the broadband regenerator - which it hopes can squeeze a fairly decent speed - up to 5Mbps - out of lines that have struggled before.

BBC: When will UK rural areas get fast-speed fibre internet?