Advantage to a Rocket?

About ninety percent of the weight of a rocket is the fuel required to reach orbit. The payload has to share in the remaining ten percent.

`Delta v = v_e ln(m_f / m_e)`

Rockets are complex and expensive like an airplane but with the exception of SpaceX they can only be used for a single launch.

A large amount of explosives is inherently dangerous and can easily be weaponized when combined with long range, high velocity and precision steering.

Advantage to the Space Shuttle?

Although the Space Shuttle looked like a plane, it did not use aerodynamic lift until the final stages of descent and landing.

To recover the main engines the orbiter had to carry 78.000kg to orbit and back. This was only possible by using two solid rocket boosters and sacrificing the external main tank.

Why not a use a Plane?

Conventional planes are heavier than air and need aerodynamic lift to take off. Climbing through the atmosphere they have to increase their velocity to compensate for decreasing pressure and density.

`F_L = ( rho v^2 A C_L ) / 2`

Civilian planes typically fly below 15000m and do not have the engine power to climb further and approach the sound barrier.

The Lockheed U2 Dragon Lady has exceptionally large wings allowing it to reach an altitude of 21300m. It used to fly in a narrow margin ("coffin corner") between stalling the plane and breaking the sound barrier.

The airship I am building can be seen as a plane lifting off from the top of the atmosphere. Neutral buoyancy at 30000m means zero wingload and stall speed, allowing the airship to gain altitude with very little thrust.

Why use Solar, not a Battery?

A Lithium-Ion battery can store about 250Wh/kg or 900kJ/kg of energy, only about three percent of the amount required to get their own mass to orbit.

Solar panels generate about 300W/kg. Enough to accelerate their own mass to orbit with 31 hours of sunlight.

Why not a Propeller?

The thrust of a propeller is governed by the same formula as the aerodynamic lift of an airfoil.

`F_L = ( rho v^2 A C_L ) / 2`

The NASA Helios prototype had to use 14 propellers with 2m diameter each to reach an altitude record of 29524m.

Credit: Wikipedia/MenteMagica

Electro-aerodynamic propulsion shares the advantage of using molecules from the surrounding air as propellant but provides a more efficient conversion from electric to kinetic energy.

Why not use a Jet Engine?

Run out of air Hypersonic Scramjet

Why not use a Rocket Engine?

X-15

What does this mean for Satellite Operators?

Cheap Launch and De-Orbit allows building Cheaper Satellites High Altitude Pseudo Satellites

What does this mean for Aviation?

Near-Space Tourism Emissionless Transportation High Altitude Observation of Earth and Space

What does this mean for Manned Space Flight?

Cargo to ISS and SpaceX ITS