Getting into space hasn’t changed much since the Russians launched Sputnik into orbit, but that may be about to change.

This image shows the planned Stratolaunch Systems carrier aircraft.(Credit:Dynetics/Stratolaunch Systems)

Ground launched rockets propel a payload into space, using more than 90% of the energy just to launch the weight of the rocket itself. Only a small percentage of that energy is used to lift the payload. Such a waste, but what if we could lower the requirements by starting the launch at a high altitude? The higher into the atmosphere you start the whole process, the less mass and thrust that rocket will need – and that saves money.

What I am talking about is an air launch of a spacecraft into orbit, the same thing that SpaceShipOne did in 2004 to win the Ansari X Prize.

Comparison of the largest aircraft(Credit:Clem Tillier)
Deep in the Mojave desert at a place called Hangar 78, Billionaire Microsoft co-founder Paul Allen (who was also behind SpaceShipOne) is funding something similar, but much larger, named Stratolaunch Systems. Scaled Composites is building the aircraft under the direction of Vulcan Aerospace and when it is complete it will be the largest in the world, but not the heaviest because it is being made with lightweight materials.

Named the ‘Roc’, after the mythical gigantic bird of prey that was said to carry away elephants, this aircraft will weigh 1.2 million pounds and have a wingspan of 385ft (117m). To put that into perspective the largest passenger aircraft, the Airbus A380, has a wingspan of 262ft (79.8m). To power this beast into the air it will have 6 Pratt & Whitney PW4056 engines with a thrust rating of 60,000lbs each. Other parts are being cannibalized from two 747’s on site.

Its unique design with twin fuselages will carry the spacecraft underneath the wings to an altitude of 30,000ft. Then the switches to release the rocket will be flipped and the Roc will turn sharply away. The rocket will angle its fins to climb into space and ignite its engines. Upon reaching an altitude of 298,000ft the first stage will break away and the second stage will fire, bringing the up to 13,500lbs of payload into orbit.

Initially the payloads will be cargo and satellites, but they are hoping to carry passengers later on, either government or private.

An artist's impression of the Stratolaunch Systems carrier aircraft releasing a rocket.(Credit:Dynetics/Stratolaunch Systems)

This isn’t the first time that an air launch system has been used, it is just the latest and the largest:

• 1963: The X-15 rocket plane reaches space after being dropped by a B-52
• 1990: Orbital Sciences (now Orbital ATK) is the first private space launch company after it launches a Pegasus rocket from a B-52
• 2004: WhiteKnight launches SpaceShipOne into space

This method of space launch has its own advantages and disadvantages:

ADVANTAGES:

• You don’t have to wait on the weather, fly the payload above or around it. “Any orbit. Any time.”
• Works well with reusable systems
• Reduced delta V needed to orbit, resulting in less cost

DISADVANTAGES:

• Limited payload size
• Airplane launch system could generate lateral forces that could damage payloads
• Elon Musk says the advantage is minimal, around 5%, over ground based launches

The whole project started with Elon Musk being a partner – he was contemplating using the system to launch SpaceX’s Falcon rockets , but he backed out after seeing what he saw as that minimal advantage. Allen pressed on, planning to service the needs of numerous companies to get into orbit.

"I think that access to space is going to change the way we live and it's going to continue to change for decades into the future. The only limit is going to be the cost and convenience of access to space and each company has its own idea of how to do that," – Chuck Beames, president of Vulcan aerospace

A part of one of the two fuselages of Stratolaunch emerges from the scaffold. (Credit:Vulcan Inc)

The main goal is to make access to space more affordable, because the cheaper it is the more companies and people that can partake in the benefits of it. The aircraft is approximately 75% complete and they are expecting to start operations by the year 2020.

Credit: Karl Tate

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Sources

• Say Hello to Stratolaunch, the World's Largest Plane
• Vulcan Aerospace: Stratolaunch
• World's Largest Plane Will Launch Rockets into Space
• Microsoft Co-Founder Paul Allen Unveils Giant Plane for Private Space Launches
• Can Billionaire Paul Allen's Mega-Plane Really Launch Private Rockets Into Space?