Kairos
Kairos was a massive single-stage, 16.8-ft-long, 96-lb rocket that competed in the 10K SRAD category. It was powered by an N3503 motor with a predicted apogee of 14,225 ft. Kairos is greek for the moment of action, as after two dual-stage builds, the team deliberately returned to a single-stage design to move focus towards expanding the scope of internal projects and member training. Kairos experienced a CATO (Catastrophe at Takeoff) at IREC.
Payload: IRIS
IRIS (In-flight Rocket Information System) was a 3U non-deployable CubeSat built on the team's iteratively refined HACS (Highly Adjustable CubeSat Structure) shelving platform. The name Iris comes from the Greek goddess of messages, reflecting the payload’s role in communicating real-time data between the rocket and the ground team. It carried a SparkFun Data Logger 9-DoF (accel/gyro/pressure/temp/magnetic flux) interfaced to a Raspberry Pi 4, transmitting live over an XBee 900HP Pro to a ground station, plus an independent payload black box (MPU-6050 + BME280 + Raspberry Pi Pico). Power came from three parallel 18650 Li-ion cells. Its mission was dual-purpose: atmospheric/flight science plus a redundant backup to the primary altimeters.
Avionics Bay
The avionics bay contained dual-redundant altimeters: Altus Metrum EasyMini (primary) and Featherweight BlueRaven (secondary), mounted on a CF-PETG sled alongside a Featherweight GPS tracker, each with its own screw switch. Batteries were mounted opposite their altimeters to prevent impact damage, secured via Velcro and zip ties.
Cherry Limeade Propellant
The propulsion team initially moved away from the GW's standard propellant formula and adopted a new research mixture dubbed Cherry Limeade. That shift led to 16 characterization tests before settling on a new formula. With a newly designed static fire test stand, the team conducted three subscale tests and one full-scale test with the new propellant, with mixed results. One subscale fire failed to collect pressure data, a second suffered a CATO from overpressurization, and the full-scale attempt also ended in a CATO. After that third failure with the new formula, the team abandoned it and reverted to GW's original formula, which they ultimately used for the competition motor.
SRAD Retention System
The Kairos motor retention system was redesigned this cycle to accommodate the TPAS v2's motor-mounted thermistor sensors, which required a gap between the motor casing and the motor tube rather than the traditional flush fit. To create that clearance, the team installed a 5 in motor tube around the 3.8 in (98 mm) motor casing instead of the standard 4 in tube, with modified centering rings closing the resulting gap and allowing sensor wiring to run internally along the case rather than externally, unlike Cerberus. At the nozzle end, a custom retainer and retaining ring held the motor casing in place, secured by a ring of socket-head bolts paired with hex nuts epoxied on the opposite face for added rigidity. Kairos did not include the TPAS v2 despite this new retention system.
