The UK government and Cornwall Council are prepared to invest up to £20m into Newquay airport (Spaceport Cornwall) to make it a base for Virgin Orbit.
Orbit is the satellite launch system currently being developed in the US by Sir Richard Branson.
This system intends to despatch rockets to space from under the wing of a converted Virgin Atlantic jumbo jet.
The investment offer is dependent on Spaceport Cornwall and Virgin Orbit putting together the business case.
If everything comes together, however, it could see the jet, called Cosmic Girl, operating out of Newquay in the early 2020s.
"We're eager to fly from lots of places, to have hubs and gateways to key orbits," explained Will Pomerantz, vice president for special projects at the Long Beach, California-based company.
"The UK is an obvious choice, given its historic strengths in the manufacturing and operation of satellites; and the Virgin connection with Sir Richard, of course," he told BBC News.
Virgin Orbit and Spaceport Cornwall have been working together for a year now and are confident they can make the commercial case for Newquay.
The funding would comprise up to £12m from the council and up to £7.85m from the UK Space Agency. There would also be a contribution of £0.5m from the Cornwall and Isles of Scilly Local Enterprise Partnership.
Virgin Orbit is putting up £2.5m of its own money to help the process along.
There is currently a major shift taking place in the business of space, which is seeing many more smaller satellites going into orbit - in the class that Virgin Orbit's LauncherOne rocket has been designed to facilitate.
This rocket has yet to have its maiden flight but Mr Pomerantz said this should happen before the end of the year. "That's what we're aiming for."
At the moment, Cosmic Girl is running simulation missions out over the Pacific Ocean from California. Very soon, the jumbo will do a drop test in which the rocket is released from under the wing and allowed to fly free - but without igniting the rocket motor.
This will check the booster's flight characteristics. Assuming that goes well, Virgin Orbit will then move towards the first full-up orbital test of LauncherOne.
Technical and regulatory hurdles will need to be cleared before the American company can operate outside of the US, and UK government officials are already working with counterparts across the Atlantic to ensure these issues are sorted out.
Julian German, the leader of Cornwall Council, commented: "Cornwall is the birthplace of innovation and technology and space is at the heart of our 21st Century economy.
"With assets like Spaceport Cornwall, world-class mission control facilities at Goonhilly Earth Station and superb digital connectivity, Cornwall will play a vital role in the growth of the global space economy."
Last year, the government announced significant seed investment in the north of Scotland to help the area establish a spaceport for rockets that climb vertically to space from a launch pad on the ground.
Tuesday's news of the potential investment in southwest England was accompanied by two other UK space announcements.
One was another funding pledge, to put £7m behind scientists at University College London to develop a new instrument – a "plasma analyser" – to monitor space weather.
Europe and America are working on new satellite concepts that would be positioned far from Earth to warn of energetic outbursts from the Sun.
In the worst cases, these colossal releases of charged particles and magnetic fields from our star can interfere with communications, trip satellite electronics, and even disrupt power grids on the ground.
The third announcement concerned the establishment of a UK National Space Council.
This is possibly a very significant development. If modelled on a similar body in the US, it would bring together senior figures in government to direct UK space policy - advised by industry and academia.
Allied to a long-called-for national space programme (and supporting budget), it could give real bite to Britain's stated aim to become a much bigger space player.
Graham Peters, the chair of the industry group UKspace, told BBC News: "Space technology and services will play an increasingly important role in the digital economy. We look forward to strengthening our partnership with government and academia to build a national space programme that will help to deliver a stronger, safer and richer future for everyone in the UK."