It was originally designed and built for billionaire adventurer Steve Fossett, who wanted to make the world's first solo dive to the bottom of the Mariana Trench.
But after he died in a plane crash, former property investor Chris Welsh, who is based in California, bought the submarine and is now taking on the lonely challenge himself.
Chris said: "I've been working day and night for two years pursuing this. I'm really excited to get out there and do it - I can't wait.
"The rewards of this is breaking ground in so many ways - in raw human exploration, on bringing back science, and in getting a better understanding of our world."
The experimental sub was created and built by British engineer Graham Hawkes.
Fitted with wings and a tail fin, its design is based on that of a plane.
Chris Welsh hopes to "fly" down to the bottom of the trench, and break the record for the first lone dive there, later this year.
After this, he and the Virgin team also plan to plunge down four other trenches around the world, with the hope of reaching the deepest point in five oceans.

It is understood that the Indian owners of the plant fear that the current UK political uncertainty could derail efforts linked to the planned sale.
Concerns centre on proposed changes to the pension scheme which are crucial to securing the future of the business.
The government says its consultation on the scheme is closed, and it will respond in due course.
Tata announced in March that it was considering selling its UK steel business, putting 11,000 jobs at risk.
But buyers are reluctant to take on the huge steelworkers' pension scheme, which has 130,000 members. Including spouses and children, hundreds of thousands of people depend upon it.
The scheme also has a deficit of about Â£700m.
In May, the business secretary Sajid Javid launched a consultation outlining options to resolve the pensions issue.
But it is understood that Tata now has concerns that the political uncertainty surrounding the Tory leadership battle could derail the process.
"It's clearly an incredibly busy time in UK politics," a source close to the company said.
"Nevertheless, the company still hopes that the hundreds of thousands of people in Britain who are dependent on a steel pension will not be left worse off by the current political leadership uncertainties."
The consultation on Tata's pension scheme is being handled by the Department of Work and Pensions.
On Wednesday the Work and Pensions Secretary Stephen Crabb announced his intention to run for the leadership of the Conservative Party.
He is being backed by Sajid Javid, who hopes to become chancellor if Mr Crabb wins. Mr Javid has led efforts to resolve the crisis in the steel industry which has intensified under his watch.
That's led to concerns that the leadership race could take priority over efforts to resolve the pensions issue.
The consultation on the scheme closed on 23 June, with a government response due four weeks later, just before the summer parliamentary recess.
The Tata Steel pension consultation included a plan to base the scheme's annual increase on the CPI measure of inflation rather than RPI, a move expected to save billions of pounds.
While reducing payouts, the plan would leave most pensions holders either better off or no worse off compared with entering the Pension Protection Fund - the industry lifeboat for pension schemes that go under.
But the plans have been criticised for setting a precedent that could lead other employers to attempt to dilute their pensions promises.
A DWP spokesman said: "Our consultation into the British Steel Pensions Scheme has now closed. We have received over 5,000 responses and will respond in due course."
You can follow John at @JohnMoylanBBC

People served by the Rosemarkie transmitter will lose Radio Scotland, Radio Nan Gaidheal, and BBC national radio services for short periods.
DAB radio and TV services are unaffected.
The disruption is expected over the course of the day. BBC Scotland said it apologised for the loss of service.
Listeners in the Inverness and Inner Moray Firth area were expected to be the worst affected.
The final phase of disruption is expected to last for about two hours from 12:45.
The Deep Flight Challenger submersible has been backed by Richard Branson's Virgin empire, and is currently undergoing its first water trials.
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Fresh concerns have emerged over the future of Tata Steel's UK assets, which include the huge Port Talbot works.
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BBC radio listeners in the Highlands could find their service affected due to essential transmitter work taking place on Tuesday.