This blog likes to keep its feet firmly on the the ground and not up in the stars. However on Sunday I happened to chance on the “Sky at Night” which was talking about a mission to the stars. This is something I had heard about in the news, Professor Stephen Hawking is involved as are a load of tech billionaires. The idea is to shoot micro probes to the nearest star or nearby stars at up to 20% of the speed of light. At this speed getting to Proxima Centauri and even a peak at the newly discovered planet orbiting it.
The idea is to launch some very small probes (lots of them) in orbit. They would unfurl a microspically thin solar sail. LASERs on earth would blast the sail with light accelerating them rapidly towards the speed of light. There are a number of technical problems with this. How to communicate with the probes at such speeds, what to make the sail out of so it survives space and high powered LASER blasts and where the power is going to come from?
Leaving aside moral and cost concerns (the project is really only the same cost as the large Hadron Collider), a 100GW is a lot of juice. There seems to be some question as to whether all this is needed at once, the projects website is very vague. However, this amount of energy is not trivial. This got me thinking would we need world wide power grid. Maybe useful for a number of reasons, but technically probably be impossible with current transmission technology. Also linking continents wouldn’t be worth it with the levels of transmission power that current interconnectors have. Next it got me thinking about total spare capacity at night. The obvious place to start is the US. It has a 1000GWp capacity. Obviously not all this is available all the time but in principle the US might be able to provide the power at night time. This is today though and not in 20 years time when the starshot is being talked about. Then patterns of energy use such as electric cars and changes in capacity might make this far more difficult.
The wikipedia page is better than the official project website.