## 3 Background
### Propulsion System Technologies Overview
#### 3.3.1 Chemical Propulsion Systems
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Product** & **Manufacturer** & **Thrust** & **Specific Impulse** & **Propellant** & **Status** \\ \hline Micro-Thruster & \begin{tabular}{c} Marotta, \\ Montville, NJ, USA \\ \end{tabular} & 0.05–2.36 N & 65 s & Nitrogen & TRL9 \\ \hline Butane & \begin{tabular}{c} SSTL, \\ Guildford, UK \\ \end{tabular} & 0.5 N & 80 s & Butane & TRL9 \\ \hline MEMS & \begin{tabular}{c} NanoSpace, \\ Uppsala, Sweden \\ \end{tabular} & 0.01–1 mN & 50–75 s & Butane & TRL8 \\ \hline POPSAT & \begin{tabular}{c} MicroSpace, \\ Singapore \\ \end{tabular} & 0.083–1.1 mN & 32–43 s & Argon & TRL8 \\ \hline HIP1-CNAPS & \
\begin{tabular}{c} UTIAS/SFL, \\ Toronto, ON, Canada \\ \end{tabular} & 12.5–40 mN & 40 s & Sulphur Hexafluoride & TRL9 \\ \hline CPOD &
\begin{tabular}{c} VACCO, \\ South El Monte, CA, USA \\ \end{tabular} & 25 mN & 40 s & R134a & TRL6 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Cold and Warm Gas Propulsion Systems [23]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Product** & **Manufacturer** & **Thrust** & **Specific Impulse** & **Status** \\ \hline GR-1 & Aerojet Rocketdyne, Sacramento, CA, USA & 0.26–1.42 N & 231 s & TRL6 \\ GR-22 & Aerojet Rocketdyne, Sacramento, CA, USA & 5.7–26.9 N & 248 s & TRL5 \\
1 N HPGP & ECAPS, Solna, Sweden & 0.25–1.00 N & 204–235 s & TRL8 \\ HYDROS & Tethers Inc., Bothel, WA, USA & 0.2–0.6 N & 258 s & TRL5 \\ BGT-X5 & Busek, Natick, MA, USA & 0.5 N & 220 s & TRL5 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Green Propellant Propulsion Systems (NASA, 2015) [23]. The use of solid rocket motors to power nanosatellites is rare; however, NASA did attempt to develop a suitable system that could accommodate the weight, power, and volume restrictions of a nanosatellite. It was developed in conjunction with Thiokol Corporation for the MagCon mission. A special casing was developed bringing the entire systems weight down to 0.4 kg. This miniaturized motor could develop 20 ms of impulse in a vacuum with a power supply of 3.3 V of direct current. In comparison, a motor with a much larger 150 mm tank diameter can deliver 100 N-s of total impulse in the same conditions. The mass of this system is 1.25 kg (almost an entire 1.38 kg U) compared to the miniatures 0.4 kg weight [2; 31]. When a solid fuel mixture is combusted, several factors affect the impulse produced by the high-pressure high-temperature exhaust gases. The amount of torque produced depends on the area of the flame front. The gases are then passed through a nozzle to accelerate the flow [30]. The reaction force produced can be calculated by [PERSON]'s third law of motion. The nozzle affects the torque produced. The throat of the nozzle (smallest cross-sectional area) will determine the Mach number of the flow which can then be substituted into a version of the general thrust equation, see Figure 16[30]. Figure 16: Physics of a Solid Rocket Motor [31]. Figure 15: HYDROS [35]. Solid rocket motors for nanosatellites are not widely used and are extremely expensive. They provide a very viable option theoretically; however, factors such as price, availability, and suppliers reduce their viability [3]. Typically, Solid rocket technology is implemented into designs upon which impulse maneuvers such as insertion and de-orbiting are required. The solid propellant achieves moderate specific impulses and high thrust magnitudes making it suited to larger buses, rather than smaller CubeSats (Table 9). A thrust vector control system is usually integrated to allow larger changes in velocity than an uncontrolled system [23].