Before I go into detail, let's explain why we need it. So far, our space crafts are carried out of orbit by traditional rocket engines. Those are essentially internal combustion engines, hence they burn some type of fuel to create a jet stream and drive the craft forward. This, although the best option at the moment, has quite enough limiting traits to call for improvement.
This is what a shuttle looks like moments after take-off. The huge giant red thing with the stuff on the sides is initial delivery system to take the craft outside of the Earth's orbit. The red cylinder is the external fuel tank, which provides the fuel needed to ascend the shuttle outside of the atmosphere. Around seventy percent of the thrust is provided by the two SRB's (solid rocket boosters) and the rest by the shuttle's main engines. Upon the various stages before entering orbit the SRB's and the external tank get separated from the shuttle which is to execute it's mission.
The shuttle itself is about ten percent of the entire payload weigh upon lift-off. Furthermore, there is also fuel located inside it, so the actual equipment and supplies it can carry is even lower.
Clearly, it's not efficient enough for interplanetary transport and travel, however, it's the best we have, so far.
Lightcraft Technologies tries to challenge that notion with their conceptual "Lightcraft" (hence the name of the company)
It uses beam propulsion system as a drive force. This beam propulsion is essentially a laser hitting the desired object to propel it forward. Sounds simple, right ? Well, it's much more interesting.
This is the concept model for the lightcraft. It uses an acorn shape for better aerodynamics and stability. The idea is to project a laser beam from the bottom side. For this purpose the company uses a PLVTS (Pulse Laser Vulnerability Test System). This is a pulsed laser with a power of ten kilowatts, developed by the US Military as a part of an anti-missile defence system. It "shoots" it's target more than twenty times in a second. In other words, it's really, really powerful.
The second milestone in the lightcraft's design is the parabolic mirror.
On top is a diagram of a parabolic mirror in action. The lines coming from the top are rays of light (in out case the laser). Once they hit the mirror, it reflects and aims all individual rays into a single point. That focused point will get super heated to 10 to 30 thousand degrees Celsius. For reference the surface of the Sun is around 5500 degrees Celsius - an average of four times cooler. Pretty hot, right ?
So, what do you think happens when you superheat something up to that temperature ?
Yup, It explodes.
To elaborate, the air is aimed and gathered into the focus point of the mirror. It then super heats and ionizes, losing electrons. The plasma combusts and creates an explosion which will propel the craft forward. These explosions occur every time a pulse hits the mirror (more than 20 times a second), so while the laser can reach it's target, it will go forward no matter what.
In the outer layers of the atmosphere where the air is not as dense, hydrogen can be used as a replacement.
The idea sounds great for atmospheric and orbital transportation, but when we consider interplanetary travel and furthermore, deep space travel, this propulsion system has a large gaping hole in it's concept. As lasers are practically a stream of focused light beams, they cannot travel forever. Light diffuses over distance - the greater the distance the larger the area covered, but smaller the intensity. This means lasers can only go so far, before they are too weak to provide the needed heat.
To achieve the idea of blasting ourselves to wherever our heart desires, we have to get something better. Scientists are trying to recreate the theoretical phenomenon known as Bessel Beam, however, with no apparent success.
Well, for now, everything around the lightcraft stays experimental, but in future years it can become reality and revolutionize our transportation system. In reality though, Lightcraft Technologies have a working model that can reach several hundred metres of altitude. In 2000, on the White Sands Missile Range the 12.2 centimetre prototype reached 71 metres in the air.
The prototype used for testing get's spanned primer to lift-off, much like an ordinary spin top. This improves the stability of the craft during ascension.
This new propulsion system is far better than the rocket engines we use at the moment because of two key improvements.It's propulsive efficiency (the ratio between the energy used and the propulsion energy generated) is up to six times bigger than the one of the standard shuttle's engines. That means it requires far little energy to achieve the same results.
Furthermore, the craft is only obligated to carry small engines for use in navigation and control. Thus, the huge fuel tanks and combustion chambers get cut off. This eliminates those 90 percent of weigh of our shuttles upon take-off. This space can be used to carry more useful equipment, on-board electronics and even...passengers.
The benefits of having the propulsion system outside of the actual craft doesn't end with one craft only. The same "engine" can be used on multiple vehicles and for multiple directions.
In the near future, this technology will stay on the missile ranges, however, I, personally, am thrilled to see what will come out of it. Who knows, maybe our children will ride the spinning ship on daily trips form London to Tokyo and back. For now though, we can only wait and spectate as science forges our path forward.
Now, I leave you with video footage of the live tests. Hope you have enjoyed, and I'll see you guys in the next one.