Not the US dollar, euro, British pound, or Russian rubel – it’s bitcoin – a virtual currency that the founder of Virgin Groups has invested £17.8 million in fundraising for BitPay, a software program that processes payments in the digital currency.

Richard Branson, who has for the past year accepted bitcoin in payment for airline travel on his Virgin Galactic Spaceship project, has now put his own personal money into the virtual currency.

Customers wanting to buy a seat on his Virgin Galactic space travel vehicles in future can pay the $250,000 right now using bitcoin, with the transactions processed using the BitPay software in which Branson has now invested.

Branson has also bought some of the virtual currency for himself, making him one of the more high profile investors in Bitcoin.

Bitcoin is not recognized by any central bank, though the German government has granted it a limited degree of official status as a “private currency.” This means that transactions carried out in the currency are taxable, and it can be exchanged freely for euros within the banking system, but is not legal tender.

The value of one bitcoin has fluctuated wildly throughout its existence. In April 2013 it hit $266, but dropped to $50 within a week.

Last November the exchange rate reached $267 per bitcoin, which was a record at that time, but is $497 at the time of writing.