There are currently three active funding for the projects: one BAP project and two TUBITAK-1001 projects.

In-space propulsion of spacecrafts and satellites are provided by specially designed thrusters that operate efficiently in vacuum environment of interplanetary-space or earths orbit. In order to develop and test thrusters to be deployed on spacecrafts or satellites, vacuum facil- ities that provide the vacuum environment that is similar to the environment in low earth orbit are used. In this project, the acquisition and construction of a vacuum facility that is going to be used in the development and testing of in-space propulsion systems are made.

The constructed vacuum facility should provide the vacuum environment that is similar to the environment in low earth orbit even when a thruster is in operation inside the chamber (when releasing gas into the chamber). The vacuum facility will primarily be used to develop electric spacecraft thrusters that run on Xenon or Argon propellants. Thus, as a baseline requirement the vacuum facility ( 1.5m in diameter, 2m in length) should employ pumping systems that is well suited to pump Xenon and Argon gases and maintain a vacuum level of 2x10^-5 Torr when 1mg/min of gas is being released by the thruster.

This BAP project has a total budget of 222k TL. This project has officially began on April 9, 2012 as a 1 year project. It was granted a 1 year extension. It will be closed on April 9, 2014. There is about 26k TL unspent money in this project's budget that needs to be spent as soon as possible.

Spenditures on BAP-6184

So far two major purchases were made. Both purchases have arrived and the budget has been accounted for. The 1st purchase was for the metal of the vacuum chamber. The second purchase was for the mechanical pump, pressure sensor, and few feedthroughs.

This project proposal was submitted on September 7, 2012 and the announcement for the awardees were made on January 11, 2013. This project officially began on March 15, 2013. It has a duration of 3 years with a total budget of 390k TL including the payment for the department and the PTI. This project promises the manufacturing and testing of a hollow cathode and a numerical modeling effort for the cathode insert region plasma.

Ion engines and Hall effect thrusters need a cathode for two reasons. The first reason is to supply the electrons needed to ionize the neutral propellant gas. Ionization is needed, because the Hall effect thrusters and ion engines work on the principle of electromagnetic forces accelerating the charged particles of the propellant. In both the standard (Kauffman type) ion engines and the Hall effect thrusters the ionization of the propellant gas, thus the plasma generation, occurs with the process called electron-impact Ionization. For this ionization process, the required electrons are supplied by a hollow cathode. The second reason is to provide the electrons needed to neutralize the ion beam leaving the thruster, thus the satellite or spacecraft. This is needed to prevent the spacecraft from charging (thus preventing the propulsion systems continued operation). In terms of the performance and the operational life of both the Hall effect thrusters and the ion engines, the cathode material, physical configuration and the structure are of great importance.

This project will have two major parts, an experimental and a theoretical (modeling) part. On the experimental side, a lanthanum hexaboride (LaB6) hollow cathode to be used for the operation of an ion engine or a Hall effect thruster will be designed and manufac- tured. Lanthanum hexaboride has been chosen as the cathode insert material, because of its lesser sensitivity to impurities in the propellant gas and lesser sensitivity to humidity, and its better suitability to laboratory testing where exposure to atmosphere is common. In the development of the hallow cathode, the studies and designs at NASA's Jet Propulsion Laboratory (JPL) will be used as a reference starting point. The target current values will be in the 0.5-3.0 Ampere range. In order to achieve the targeted cathode current levels, the propellant flow to the cathode will be adjusted. It is estimated that a 100W heater unit will be required to allow the starting of the cathode within 120 minutes. After the cathode starts its operation no other heater power would be required.

On the theoretical side a two dimensional axisymmetric numerical model of the discharge region of a hollow cathode will be developed. The driving physics inside orificed hollow cathodes is not well understood. Such a study will complement and aid the development effort of the cathode.

As part of this project it is possible to employ three graduate and one undergraduate students at a given time. 3 graduate students (Oguz Korkmaz, Sina Jahanbakhsh and Ali Enes Ozturk) and 1 undergraduate student (Firat Sik) are being paid through this project's budget.

This project proposal was submitted on March 8, 2013 and the announcement for the awardees were made on July 12, 2013. This project officially began on October 1, 2013. It has a duration of 3 years with a total budget of 440k TL including the payment for the department and the PTI.

This project will consist of experimental and theoretical (modeling) parts. In the ex- perimental part of the project, a prototype radio-frequency ion engine will be designed, manufactured and preliminary performance tests will be carried out. The prototype ion engine that will be produced as part of this project is expected to have a cylindrical dis- charge chamber of 72mm in diameter and 70mm in length. Due to fact that the produced ion engine will only be a laboratory prototype, initially the grids with 91 and 127 holes packed in a hexagonal shape are going to be manufactured and the necessary tests will be performed. During the design phase different materials and production methods will also be investigated. The design and the manufacturing of the prototype ion engine will benefit from the studies and designs of NASA's Jet Propulsion Laboratory (JPL) and the research conducted under the partnership of University of Giessen and EADS Astrium in Germany. The targeted thrust value of the prototype ion engine is in the range of 2-4 mN. In order to achive this thrust, the propellant flow rate, the grid spacing, and the discharge potential values will be adjusted. Other desired parametric studies will be conducted.

In the theoretical part of the project, the ionization chamber of the radio-frequency ion engine will be modeled. In radio-frequency ion engines, the ionization of the neutral propel- lant gas is achieved by an antenna wrapped around the ionization chamber. The working principle behind the ionization of the netutral propellant gas using the energy transmitted to the plasma by radio frequency waves will be studied. Modeling of the ionization chamber plasma of an RF ion engine is related to an important research topic called the inductively coupled plasma (ICP). With the numerical model that will be developed as part of this research, an important step towards the understanding of the working principle of an RF ion engine will be made. The developed model will also be used in the design phase as well as the analysis of the test results of the prototype thruster.

As part of this project it will be possible to employ 3 graduate and 1 undergraduate students. 3 graduate student (Mert Satir, Nazli Turan and Yavuz Emre Kamis) and 1 undergraduate student (Yigit Can Sezgin) are being paid through this project's budget. However, the work conducted by Emre Turkoz has been directly related to the promised work in this project. Emre has been an unpaid gradaute researcher for this project. The promised numerical work has already been completed.

Satellites and spacecrafts moving in an orbit or in interplanetary space use propulsion systems that use the principle of conservation of momentum to provide thrust. In addition to the typically used chemical thrusters, use of electric thruster are increasing over the last several decades. Electrothermal systems are the most common ones between the electrical propulsion systems. In these systems electrical energy is used to heat up the propellant. Resistojets and Arcjets type electrothermal systems are used in main space systems like international space station, communication and observation satellites since 1960’s. Even though specific level of these systems (300-2000 s) are relatively lower than the other electrical systems they are chosen for the better systematic and structural simplicity, productibility and reliability then other systems. Microwave Electrothermal System,the third type of the electrothermal systems, are designed to reduce the thermal endurance and lifetime limits of Resistojets and Arcjets. Although Microwave systems are not employed on any space platforms very good results are achieved from the experiments conducted to date and the developments in electromagnetic science will provide sustainable improvements in these systems. The most important component of the microwave electrothermal thruster is the resonant cavity in which the cold gas is heated up. In order to supply proper electric field intensity to initiate plasma discharge resonant cavity must be design very properly.

In this project resonant cavity which is working in TM₀₁₁ mode for microwave electrothermal thruster which uses 2.45 GHz frequency and 1 kW power will be designed, produced and numeric analysis is done. Project will have both experimental and numerical modeling parts. In experimental part of the proposed project a prototype resonant cavity will be designed, suitable production methods will be searched and chosen, a prototype will be produced. In the theoretical part, modeling of resonant cavity is done by using the commercial software. Effect of cavity geometry and dimensions on the electric field distribution in the cavity is examined. Ensuing work will be done on enhancing the system efficiency and integration of the components of the microwave electrothermal thruster system.

This BAP project has a total budget of 35k TL. This project has officially began on September 30, 2014 as a 1 year project.