The prototype microwave-electrothermal-thruster (MET), designed and built by Mehmet Serhan Yildiz, is successfully tested inside the BUSTLab vacuum chamber. The thruster operates at 2.45 GHz microwave frequency. Power levels of up to 550 W was delivered to the thruster during its initial tests. The first picture below shows the power generation and delivery system located outside the vacuum chamber. The power is brought inside vacuum chamber with high power microwave cables and a 7/16" power feedthrough. The second picture shows the prototype MET thruster, placed on a stand, and its high power microwave connections inside the BUSTLab vacuum chamber. The third picture shows a close-up view of the MET thruster before its initial tests. The fourth picture shows the thruster in operation inside the chamber. The last picture is taken from one of the side viewports of the BUSTLab vacuum chamber. From the forth picture, through the circular window port on the thruster, it is possible to see the plasma inside the resonant cavity of the thruster, as well as the plume exiting the nozzle of the thruster.