Dereck Chiu

Electric propulsion for small satellites

Propulsion is required for satellite motion in outer space. The displacement of a satellite in space, orbit transfer and its attitude control are the task of space propulsion, which is carried out by rocket engines. Electric propulsion uses electric energy to energize or accelerate the propellant. The electric propulsion, which uses electrical energy to accelerate propellant in the form of plasma, is known as plasma propulsion. Plasma propulsion utilizes the electric energy to first, ionize the propellant and then, deliver energy to the resulting plasma leading to plasma acceleration. Many types of plasma thrusters have been developed over last 50 years. The variety of these devices can be divided into three main categories dependent on the mechanism of acceleration: (i) electrothermal, (ii) electrostatic and (iii) electromagnetic. Recent trends in space exploration associate with the paradigm shift towards small and efficient satellites, or micro- and nano-satellites. A particular example of microthruster considered in this paper is the micro-cathode arc thruster (µCAT). The µCAT is based on vacuum arc discharge. Thrust is produced when the arc discharge erodes some of the cathode at high velocity and is accelerated out the nozzle by a Lorentz force. The thrust amount is controlled by varying the frequency of pulses with demonstrated range to date of 1‐50Hz producing thrust ranging from 1 µN to 0.05mN.

Cold Atmospheric Plasma (CAP) Combined with Chemo-Radiation and Cytoreductive Surgery: The First Clinical Experience for Stage IV Metastatic Colon Cancer

The authors report the first clinical experience using CAP for Stage IV metastatic colon cancer. The report describes the patient’s history, chemotherapy, radiation, surgical treatment and ex-vivo and intra-operative treatment of the tumor and normal tissue with CAP. Evaluation of intra-operative temperature, oxygen and end tidal CO2 measurements during the surgery and post-surgery analysis of tissue treated by cold plasma. In vivo studies suggest that TRAIl-R1 expression increases in the CAP treated liver tissues, suggesting that the death receptor molecule may be involved in inducing apoptosis. Three-month postoperative CT scan of the abdomen and pelvis revealed no evidence of recurrent tumor at the resected and cold plasma treatment sites.

Micro-Cathode Arc Thruster for small sattelites attitude control

Summary form only given. A low-mass, low-volume propulsion subsystems based on electrically activated micro-thrusters that utilize chemically-inert solid propellants are beneficial for small satellite attitude control applications. Micro-thrusters are able to deliver small impulse bits of about several μNs to satellites and characterized by simplicity, scalability, low cost, low weight and high reliability. In this work measurements of the key parameters of micro-Cathode Arc Thruster (μCAT) are presented and μCAT performance compared with other commercially available thruster technologies operating at the same power range.