The Virgin Galactic unveils its new SpaceShipTwo spacecraft at the Mojave Spaceport in California. (File: Getty)
Virgin Galactic isn’t the only company looking at ways to offer space travel to the masses. Insiders forecast that commercial space aviation could be a US$1 billion industry.
Ten days ago, British business magnate Richard Branson announced a new Virgin venture – Virgin Volcanic: an expedition to the centre of Earth through an active volcano.
As you probably guessed, it was an April Fool’s joke – a very cheesy one, too, as days earlier James Cameron had just reached the ocean’s deepest point, an (actual) expedition that was well discussed on The Conversation.
The Virgin Group is a corporate empire consisting of about 400 companies around the world. But there’s one Virgin venture that is of particular interest and has the potential to be truly groundbreaking: Virgin Galactic – offering commercial seats for space travel.
In December 2009, Virgin Galactic unveiled its first commercial spaceship – the VSS Enterprise – based on the SpaceShipTwo spacecraft model (discussed below). The VSS Enterprise is 18 metres long and capable of taking six passengers and two pilots to space.
But what are the challenges? And what exactly is involved? Let’s take the example of Virgin Galactic’s spacecraft and discuss a few points, such as:
HOW DOES IT WORK?
The Virgin spacecraft base model (SpaceShipTwo) does not launch vertically from the ground but horizontally from an aircraft (the WhiteKnightTwo) that takes it to around 50,000ft (about 15km) altitude. By launching at such high altitude, Virgin claims any engine issues that may arise on the way would simply lead to a return journey “gliding” to the ground, adding a layer of safety in case of emergency.
Also, by using a “carrier aircraft plus spaceship” combination to get into space, the set-up required is smaller and lighter than that for rocket-launching systems, which require far greater power. Another advantage is the ability to avoid delays caused by bad weather, as the aircraft can simply climb to a more suitable launch position if required.
The idea to air-launch came from Burt Rutan, founder of Scaled Composites. Rutan is an aerospace engineer who is well known for winning the Ansari X-Prize in 2004, when his company successfully launched SpaceShipOne: the first privately-funded spacecraft to enter the realm of space twice within two weeks. His work caught the eye of Richard Branson, who asked him to join the Virgin Galactic team.
WHAT IS THE VIRGIN SPACECRAFT MADE OF?
Virgin Galactic opted for what they call an “all carbon-structure”. That means the spacecraft features a large quantity of carbon-reinforced composite materials. Composite materials are a combination of more than one material, with the final product having better properties than its individual components.
Carbon-fibre-reinforced composites have a great strength-to-weight and stiffness-to-weight ratio compared to traditional materials, such as steel. This allows for lighter structures, which leads to lower energy requirements (less fuel) to move the structure. They are also more resistant to fatigue and corrosion than metals, and this lowers maintenance costs.
But Boeing and Airbus have both had well-documented issues with composite materials manufacturing. Ensuring high quality on a large scale is no easy task.
The counter-argument is that Virgin Galactic won’t have to manufacture large numbers of their SpaceShipTwo spacecraft in the way Airbus and Boeing do.
On its website, Virgin Galactic claims structural changes can be made if there’s a need, and that it’s as easy as “simply bonding on additional pieces”. But, actually, no – it’s not that easy.
People spend entire PhDs trying to optimise composite material properties or enhance manufacturing processes (including the bonding process). But Virgin Galactic is right when it highlights the fact composite materials offer a greater amount of flexibility and “tweaking” than traditional materials.