High power electromagnetic plasma thrusters are being developed as primary in-space propulsion systems for future robotic and piloted space missions. Electromagnetic thrusters effectively process megawatts of electrical power, providing a wide range of specific impulse values to meet a variety of inspace propulsion requirements. Potential applications for high power thrusters include the orbit raising and maneuvering of large space platforms, lunar and planetary cargo transport, piloted planetary missions, asteroid rendezvous and sample return, and robotic deep space exploration. The NASA Glenn Research Center is developing MW-class magnetoplasmadynamic (MPD) thrusters and pulsed inductive thrusters (PIT) to support these diverse mission requirements. This paper provides an overview of the current GRC research program, describes the operating principles, challenges, and status of each technology, and outlines plans for further development.