The avionics-payload bay were both designed in SolidWorks with an emphasis on strength, accessible installation, and accessible payload deployment. Ease of 3D printing was another consideration. The avionics bay supports the attachment of Eggtimer Apogee and Eggtimer Classic flight computers. Two Lipo 1S batteries are screwed into place via M2 screws to minimize the risk of a wire disconnecting.

The subsystem components are composed of the:

• Avionics bay mount

• Battery enclosure

• Deployment rail

• Support rail

• Mounting disk

• 2U CubeSat

Installation involves part-level and component-level assembly. Part-level assembly refers to the installation of individual parts, whereas the latter refers to the installation of the payload.

Part-Level Assembly

After the Lipo 1S batteries are placed in the enclosure, the enclosure is secured to the mounting plate via M2 screws. This enclosure minimizes the risk of a wire disconnecting. The avionics bay is then glued to two mounting disks via epoxy resin. Four steel-cylindrical rods are slid through the holes on the mounting disks. Bolts are used to secure the rods in place. The payload deployment rails are attached to the mounting disk of the avionics bay via steel-reinforced epoxy; there are indents for installation. 

Component-Level Assembly

With the deployment rails installed, the CubeSat is slid into place. The final mounting disk is attached to the support rails and is locked into place via eyebolts. The simple design of the avionics-payload bay allows it to be quickly slid into or out the rocket when necessary.

The rocket utilizes a dual deployment recovery system; two flight computers are used. At apogee, a charge ignites to separate the lower body tube and upper body tube to deploy the drogue parachute. At 1,000 ft, another charge fires to separate the nosecone from the upper cone; the main parachute is deployed. For this system to be possible, the avionics bay was placed near the mid-section of the rocket. In which, the drogue parachute is placed below the avionics bay, whereas the main parachute is placed above. Both parachutes are secured to their respective avionics bay eyebolts.

OpenRocket was initially used to evaluate the stability and flight characteristics of the rocket. In level one and two rocket designs, the avionics bay was placed directly beneath the nose cone's shoulder. However, simulations showed that the rocket was over stable at 4.79 cal. Placing the avionics-payload bay closer to the lower body tube caused the rocket to be unstable. Subsequently, the avionics bay was placed near the mid-section of the level three rocket to increase stability. To obtain a target stability value of 1.25, four fins were used and the fin's sweep length were increased; the down-side of the four fin configuration is that the rocket would be less aerodynamic. The predicted mass from SolidWorks was inputted to obtain more accurate results. A M650W-P motor was used to achieve the target altitude of 10,000 ft (3,048 m).

Flight Characteristics:

Apogee: 3400 m.

Max velocity: 282 m/s.

Max acceleration: 93.6 m/s^2.

Velocity at drogue parachute deployment: 0.8 m/s.

Velocity at main parachute deployment: -11.3 m/s.

Descent / Ground hit velocity:  5.14 m/s.

Time to apogee: 25 s

Flight time: 253

Analysis of these flight characteristics shows that the parachutes will not experience any deployment failures due to shocks.

RASAero and RockSim were used to verify whether the OpenRocket results were accurate. All relevant characteristics were entered as accurately as possible into each program; all simulations shared the same initial conditions. However, some elements/features were not present. This is why there is a wide variance in data. By closely examining each program, RockSim shares the most similar data to OpenRocket. More specifically, the apogee obtained, time to apogee, and max velocity are relatively similar. Subsequently, it can be concluded the simulation set-up in OpenRocket was correct. Furthermore, it could be concluded that the simulation results should closely mirror the experimental results.