After years of designs and numerous times back at the drawing board learning the ropes of liquid rocketry, Caelus Rocketry ran its first-ever hardware test. The initial cold flow test verified initial designs for plumbing, flight software, and pressurization procedures for the ethanol propellant system. This test utilized water pressurized with nitrogen to serve as a proof-of-concept for methodology and development processes, as well as safety procedures and protocols.

The Caelus team presented our design for the Aphlex 1B engine at the AIAA Young Professionals, Students, and Educators (YPSE) 2020 conference and took home the "Best High School Presentation" prize for our design paper titled: "Development of a Cost-Effective 1.5kN Liquid-Fueled Rocket Propulsion System"

The second essential test conducted by Caelus, the nitrous water cold flow test further tested plumbing system design as well as electronics, programming, and safety procedures. This test once again utilized water pressurized with nitrogen in the nitrous oxide propellant system. This test was successfully conducted 3 times in one day!

With the team's growing experience and grasp of rocket science, we tackled an engine redesign to optimize our engine's performance with our hardware constraints. With this process, we increased our planned thrust from 1,500 to 2,500 Newtons and the Aphlex 1C engine has the potential to reach our target altitude of 5,000 feet with continued improvements.

Following a complete overhaul of the electronics and programming systems for the Aphlex 1C test stand, we ensured that pressure could be handled on the ethanol side of our test stand, validated sensor data, calibration, and leak testing procedures.

This test ensured that the test stand can hold and maintain pressure for propellants, gain accurate readings from all sensors and probes, successfully actuate all valves, and deliver the necessary conditions for combustion to the engine, using inert water instead of reactive nitrous oxide.

The full water cold flow unifies the testing of the ethanol and nitrous towers by simulating the responsibility of managing two towers simultaneously. It requires improved organization and logistical management of procedures for each tower and reliability of all electronics, software, plumbing, and structural elements for each tower, as the range of failure modes is more than doubled.

After almost 5 years of work and dozens of extensive tests on our system, we decided that a full redesign was necessary to incorporate all the experience we had gained in order to create a new and better system of the quality needed to launch Callisto 1. Project Caelus was reborn with the goal of more performant and reliable technical architecture along with a re-envisioned operational structure, under the new name of Caelus Rocketry.

In applying what we learned from our tests and failures with Project Caelus for years before, we were able to design an entirely new (and better) system from scratch in 7 months. We created a new engine, Aphlex 1D, with the help of NASA, whom we reached out to. Our new test stand is now in two parts, one for the flight stand and one for the ground stand. This helps with structural stability and transportation. Our new avionics system is streamlined and reliable.