At 200 km there is still enough residual atmosphere to slow a satellite measurably. Left unchecked, that drag pulls a spacecraft back to Earth in weeks. The property that makes VLEO self-cleaning is the same one that makes it hard to stay in.
The conventional answer — carry propellant and burn it to fight drag — doesn't scale. Chemical systems need impractical volumes of fuel; even efficient electric thrusters carry a finite tank. ESA's GOCE ran dry after four years; JAXA's Tsubame after about 111 days.
The shift in thinking
Air-breathing electric propulsion stops fighting the atmosphere and starts using it. The residual air becomes the propellant.
The four stages
- Intake. A forward-facing intake collects residual atmospheric molecules.
- Collection. Those sparse molecules are concentrated into a usable stream.
- Ionization. The gas is ionized — no onboard fuel tank required.
- Acceleration. Ions are accelerated to produce continuous thrust that offsets drag.
Proven, then commercialised
Governments already demonstrated sustained low-altitude flight. Orbitt's work is to turn that demonstrated physics into a commercial platform operators can fly — without the proprietary detail, the principle is simple: the atmosphere is the resource, not the enemy.