Virgin first unveiled the VSS Unity in 2016 and has flown it (with the rocket engine) four times now. Each test pushed the altitude a little higher: 16.0 miles, 21.7 miles, 32.3 miles, and now 51.4 miles. Unity replaced the VSS Enterprise, which broke apart in 2014 because its “feathering” airbrake system was accidentally deployed too early. That accident killed co-pilot Michael Alsbury and injured pilot Peter Siebold. Virgin took steps to make sure the same thing can’t happen on new versions of its SpaceShipTwo design.

Safety is of higher importance than ever as Virgin Galactic nears its ultimate goal of taking passengers into space. For a mere $250,000, a person can ride up to the edge of space aboard one of Virgin’s spacecraft. The trip won’t be long, but they’ll get a few minutes of weightlessness before the craft heads back down for a landing. Virgin Galactic started pre-selling tickets several years ago and says it has sold all available seats through 2021.

Eoin Treacy's view

Space tourism looks likely to be a significant growth sector in future but it is another example of an industry that exists today because we have had a decade of incredibly low interest rates which has made funding available for just anything anyone could imagine.

Tightening liquidity conditions will eventually start to curtail the availability of credit to speculative enterprises. The impending IPO of significant unicorns like Lyft and Uber can be seen as a reflection of that realisation above capital intensive but profitless businesses.