Lutz Kayser invented, developed, and tested the TIROC rocket engine (Tangential Injection and Rotational Combustion). It was the world's smallest thruster burning Monomethylhydrazine and Nitrogen tetroxide. It delivered 1 newton thrust (0.2 lbf) with a minimum burning time of 1 milliseconds and a demonstrated maximum burning time of 1 million seconds (11 days). The valves had response times of under 1 millisecond and were capable of more than 1 million cycles at a 6 sigma confidence level. Kayser also developed one of the first capillary action gas-liquid separation systems. This guaranteed positive liquid flow from propellant tanks to the rocket engines in zero-gravity. Future applications were high performance satellite and space vehicle attitude control systems.

The TIROC was licensed by unknown US manufacturers and used in classified US DoD satellites. Characteristics were:

• Propellants: N2O4/MMH
• Thrust: 1 to 10 Newton
• Tmin: 10^-3 Seconds
• Tmax:>10^6 Seconds
• ISP: 303 Seconds at 100 expansion ratio into vacuum
• Valve response:10^-3 Seconds
• Propellant inlet pressure: 40 bar to 10 bar range (600 psi)
• Chamber material: Pt90-Rh10 or Be for the larger thrust
• Dimensions incl. magnetic valves: 2x2x6 cm
• Mass: 80 gram
• Voltage: 24 VDC @ .5 A opening, .1 A holding current
• Injector type: purely tangential leading to a rotating combustion with Bessel-function gas liquid separation.

Because of the low thrust acceleration capillary action gas-liquid separation in the propellant was recommended

Bipropellant rocket engine (thruster) applications included: Satellite attitude and position control, re-entry systems, intra-orbit propulsion, docking, astronaut EVA, momentum gyro discharge.