Inside the Real Spaceship Enterprise

I refuse to use the word “Starship” in conjunction with “Enterprise” in this post. Despite the inner geek in me having a mental breakdown at that statement, it just would not be accurate in describing the vehicles that are in question.

What vehicles are they? Well, so far there have been two real-life human spacecraft thus far named “Enterprise”. One of these never actually went into space, and never will. The other will almost certainly be the next human-carrying vessel to actually go to space in known history.

The Enterprise - OV101

The first vessel named “Enterprise” was the US Space Shuttle designated “OV-101”. This was the first fully completed, flight worthy Space Shuttle. It was named directly after the fictional Star Trek vessel “USS Enterprise” in recognition of its place as a pioneering flagship of human space travel.

Enterprise OV101 never actually went to space; its purpose was primarily flight tests (and most insiders will say a huge PR booster) which demonstrated that the concept of a reusable shuttle was indeed viable. These days you can find the Enterprise in the Smithsonian’s National Air and Space Museum.

Now, on to the first real “Enterprise” in space. Feast your eyes on the VSS Enterprise

The VSS Enterprise

 The VSS Enterprise is also named directly in honour of the USS Enterprise, the “V” in “VSS” standing for “Virgin”. Everyone’s favourite British billionaire sir Richard Branson has lead a new venture to create a commercial space-liner, and the results are breath-taking

So, what can the first ever “Enterprise” in space do?

How high?

The Enterprise has an operational maximum altitude of 112km. This is 12km above the official line of “space”. The view from this height would be stunning, as seen in the picture here. This image was taken by ‘SpaceShipOne’ the 2004 prototype for the Enterprise.

To put this height into context, the international Space Station orbits at an average distance of 350km from the planet, so the Enterprise gets a third of the way there despite only being sub-orbital. The Space shuttles have a maximum range of about 400km from the planet.

Technically, at 112km you are still within the Ionosphere, but do not let that fool you. The technical atmosphere of Earth extends to arguably 600km away from the planet, but any discernable gasses like oxygen/ nitrogen are long gone once you get above 50km. here you are simply bumping against random ionised gas molecules, which technically constitute an ‘atmosphere’.

How fast?

The VSS Enterprise isn’t quite warp-capable, but it sure can move when it needs to. Its estimated flight speed is 4,200kph (2,600mph). Needless to say, this is very quick. This gives it enough speed that the initial burn of the engines lasts for just 70 seconds, allowing the Enterprise to reach space using nothing but inertia from this initial boost. 

It will hit mach 1 after just 8 of those 70 seconds, having been released from it’s mothership at a speed of approximately 400mph. Mothership?

The Enterprise being released from the mothership

The Enterprise is one of the few spaceships that is not launched from the ground. It is flown to an altitude of around 50,000 feet by its ‘mothership’, where it is released into a freefall before its own engines kick in.

 Compare the 4,200kph speed to the speed of our standard orbital space-craft (Shuttle, Soyuz etc). These craft accelerate to the required speed for orbit in about 8 minutes. Their final speed is 17,500mph, in comparison to the Enterprise’s 2,600mph. So you can see that despite the massive speed of the Enterprise, it just cannot get to orbit. 

Virgin are now talking about building an orbital craft, but that is another story.

The Engines

The Enterprise uses a hybrid engine. This is different to the twin SRB Engines used on the US Space Shuttle, in that they use a liquid oxidizer in tandem with solid fuel. The advantage of an "S/L" Hybrid engine is the controllability; it can be mannually throttled and shut-off by the pilot in the event of any trouble. The Solid fuel means it can achieve this without compromising on power. It is also much cleaner for the environment.

The motor, named “RocketMotorTwo”, will be positioned to the rear of the craft. The engine is filled with fuel for a 70 second rocket burn, using Nitrous Oxide as the liquid oxidizer, and a "Rubber Compound" as the solid rocket fuel.

Technical Diagram

It is important to note that the return trip to Earth is entirely unpowered, the Enterprise glides to an airstrip landing in much the same way as the Shuttles do. Unlike the Shuttles, however, the Enterprise does not need an advanced TPS (Thermal Protection System) as the relatively low speed won’t create the same frictional forces on ships hull.

The Passengers & Crew

The Enterprise will be crewed by 2 people, and carry a further 6 passengers. This puts it on a level with the US Space Shuttle for the record of most people transported to space in one vessel.

Aboard the Enterprise

Aboard the Enterprise you would enjoy just under 10 minutes of ‘weightlessness’ before the craft must begin its journey back to Earth. Current press images suggest that those persons aboard will wear some type of space-suit. Although the Enterprise is designed to be a ‘shirt-sleeve’ environment, it is logical to provide passengers with an o2 supply just in case there is an issue with pressurisation.

The Enterprise was completed a year ago, and has spent the last 12 months in rigorous testing along with its mothership. It is estimated to begin flying paying customers within the next 12 months.

Let’s just pause for a minute, and think about what all of this means. What Virgin Galactic are doing here is something very special. The Enterprise may not reach orbit but it is demonstrating technologies and practices needed for human space travel. They are pioneering reusable space transportation; giving anyone the chance to take the first tentative steps into the final frontier.

That’s something that has never been done before. The £125,000 price may seem steep, but it is within the realms of mere mortals. Up to now, you could count the number of privately funded humans in space on one hand. The Enterprise promises to take people up by the hundreds each year.

More than all of that though, is what it can do for our imaginations. Recently, space travel has stagnated in the minds of the public. The Enterprise represents a big chance to get space travel back on our TVs, in the news, in our minds. It actually gives people a chance to do it themselves, if they have the money.

Sounds like I need to start saving…