A new kind of space race has taken off, and this time it involves entrepreneurs eager to dominate commercial spaceflight.
Yesterday, Amazon founder Jeff Bezos, a key player in the field, announced his latest endeavour – his startup Blue Origin is investing more than $200m (£129m) in building rocket manufacturing facilities in Florida and taking control of the Launch Complex 36 pad at Cape Canaveral Air Force Station.
The company, which was founded in 2000, is set on testing its New Shepard reusable rocket, which it hopes will take humans into space in the future.
But Bezos is not alone in his ambition – this latest announcement comes at a time when private investors are showing more interest than ever in the space industry, with a growing list of big names throwing money at building innovative technologies.
No-one has quite managed to crack the space tourism nut yet, but there are plenty on the verge of doing so. Here's a list of who's who in the space entrepreneurship race.
Elon Musk – SpaceX
When he first set up SpaceX 13 years ago, billionaire Elon Musk said it was his ultimate goal to send humans to Mars.
He's still some way off achieving that, but in the meantime his startup has created some innovative designs. So much so that it has won contracts from Nasa, the US space agency, to design a more efficient system for delivering cargo to the International Space Station (ISS). It has already completed six missions under this agreement.
On the space tourism front, the company plans to test out its Falcon Heavy next year – the most powerful rocket currently in operation, which was designed from the outset to carry humans into space.
Richard Branson – Virgin Galactic
UK entrepreneur Richard Branson first branched into the space industry in 2004, when he founded Virgin Galactic – the “world's first commercial spaceline”.
The Spaceship Company, which was set up a year later to manage the Virgin's space operations, has kept us on the edge of our seats as we wait for the unveiling of “SpaceShipTwo” - the first ever suborbital plane designed specifically for space tourism.
Branson originally suggested the first flight would happen before the end of 2009, but a series of delays ensued. In October last year, Virgin Galactic experienced a setback when VSS Enterprise, one of its experimental spaceflight test vehicles, crashed in the Mojave Desert, killing the co-pilot and seriously injuring the pilot.
Following a subsequent nine-month investigation into the accident, the National Transportation Safety Board concluded that it was the result of a combination of human error and inadequate safety procedures.
There's hope, however – the finalised vehicle, which wannabe space tourists shave been waiting for for years, could be unveiled “within months”, George Whitesides, chief executive of Richard Branson's ambitious space tourism company, said last week.
Read more: Virgin Galactic's SpaceShipTwo crashes during space test flight after “in-flight anomaly” killing one and injuring a second person
Robert Bigelow – Bigelow Aerospace
Nevada-based startup Bigelow Aerospace is creating its own kind of technology – expandable station modules.
These inflatable habitats won't be much use for taking humans into space, but they'll be a great help in keeping them there.
Only last month, the company announced it was preparing to launch its BEAM habitat to the ISS, where it will spend two years providing extra space for the astronauts based there.
The reason why they're so helpful is that they are much more light ad compact than the solid structures traditionally sent into space, so make missions cheaper to launch.
Ultimately, founder Robert Bigelow hopes the invention will enable long-distance manned space flights in the future, potentially providing bases on the moon and Mars.
Paul Allen – Vulcan Aerospace
Paul Allen, who co-founded Microsoft with Bill Gates, is channelling his energy into Vulcan Aerospace – a venture started in April this year.
The aim of the company, which is a subsidiary of Vulcan Inc, is to “boost private space travel” by making it more affordable and efficient.
So far, the company has started overseeing Stratolaunch Systems, a project facilitating a move away from the current orbital launch model to a flexible, less expensive model. This includes launching spacecraft and probes into orbit from a huge carrier aircraft with a wingspan of 117 metres.
It's a new company, so there isn't a huge amount to report on just yet, but with Allen's track record for building businesses it should certainly be considered a serious contender.
Larry Page and Eric Schmidt - Planetary Resources Inc.
Asteroids are rich in untapped resources, ranging from precious metals like platinum to water, which will come in very handy if we ever run out of it here on Earth.
The trouble is, they're tricky to pin down – they're located far away in space and travel at extremely fast speeds – often heading away from Earth.
But this hasn't put off Larry Page and Eric Schmidt, co-founder and former chief executive of Google. In 2012, they founded Planetary Resources – a company aimed specifically at finding a way to mine these rocks.
The company is based on the belief that by turning asteroid mining into a major industry, it could “add trillions of dollars to the global GDP" and "help ensure humanity's prosperity."