The development of advanced propulsion technologies represents a cornerstone in the successful realization of long-term human space travel. Unlike their robotic precursors, human interplanetary spacecraft must be fast, reliable, "power rich," and be capable of reasonable abort options --essential features for the preservation of human life. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is a new approach to plasma propulsion, which addresses these issues and provides an evolutionary path to fusion rockets, but with immediate and exciting non-fusion applications along the way. A NASA-led research effort, involving government, academia and private industry teams in the United States, is exploring the foundations of this concept, and pursuing its rapid development and test. This presentation will cover the basic principles of VASIMR operation, the latest experimental and theoretical results, as well as the most important technological developments and challenges for the future. Light gas (hydrogen, deuterium, helium and mixtures) helicon plasma production and subsequent Ion Cyclotron Resonant Acceleration (ICRA) are key experimental efforts. High density (~ 10@super 19@ m@super -3@) hydrogen, deuterium and helium plasma discharges have been achieved, with nearly 50% of the injected gas being accounted for in the plasma flow. Recent experiments with a strong magnetic choke (~ 1 tesla) downstream of the helicon source have demonstrated high Mach number (> 1) plasma flows. In certian conditions, high energy (> 50 eV) ion tails have been observed from the helicon source alone. Parametric (e.g. power, gas flow, and magnetic field) studies of the helicon source will be presented. ICRA experiments are in progress, so the configuration and most recent results will be discussed. The conceptual application of the VASIMR to fast human Mars missions, as well as plans for near-term flight demonstrations will also be highlighted.