What does CAPER mean in UNCLASSIFIED

CAPER stands for Cusp Alfven and Plasma Electrodynamics Rocket. It is a type of spacecraft powered by electric and magnetic fields that use the natural plasma environment of space to generate thrust.

CAPER uses an electric field to induce a current in the surrounding plasma, which generates a force in the opposite direction. As more current is induced from this electric field, more force is generated, allowing the spacecraft to move forward. Additionally, CAPER utilizes magnetohydrodynamic principles to create lift forces in order to change its attitude during flight.

The main advantage of using CAPER is its ability to operate without using any fuel or propellants, drastically reducing cost while providing long-duration missions with unlimited maneuverability in comparison with other propulsion systems like chemical rockets or ion thrusters which require continuous refueling or have limited maneuverability due to mass constraints.

Depending on the application, some disadvantages can include higher power requirements compared to traditional propulsion systems as well as relatively low acceleration performance compared to chemical rockets or ion thrusters depending on mission requirements and operational parameters. Additionally, there are still many unknowns when working with exotic plasmas which could result in unexpected performance issues during flight operations.

In 2020, JAXA successfully tested a version of CAPER called Smart Phased Array for Radio wave propulsion (SPAR), demonstrating successfully that this technology could be used for deep space exploration missions. Additionally NASA is currently developing its own version called Variable Specific Impulse Magnetoplasma Rocket (VASIMR).