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Spaceport America Cup: ESRA 2020-2021

The Project Imua Team participated in the ERSA 2020-2021 Spaceport America Cup for its Mission 8.

The team designed a hybrid rocket and payload for the competition that was originally scheduled for launch in summer 2020. Due to COVID travel restrictions, the ESRA 2020 event was continued into 2021. The continuation of lockdown mandates forced the ESRA 2021 event to b held as a virtual conference in the summer of 2021. The hybrid rocket was evntually flown at the ARLISS 2021 competition in September at Black Rock, Nevada. The team won first first in the hybrid power motor event.

Two-Year preparations:

WCC team assembled a hybrid rocket motor. Its maiden flight was originally scheduled for this summer. Onboard was an atmospheric sensing payload consisting of a two-CubeSat-swarm (2U parent with releasable 1U child) designed by Honolulu Community College.

The propellant powering hybrid rocket motors exists in two different phases—a solid fuel and a liquid or gaseous oxidizer. SpaceShipOne, which successfully made the first private crewed spaceflight in 2004, used a hybrid motor. Unlike solid rockets, hybrids can be easily throttled and even restarted. They also pose a lower explosive hazard. In contrast to liquid rockets, hybrids are mechanically simpler, requiring fewer pumps and valves. One major disadvantage of hybrids is a decreasing thrust curve resulting from its non-constant ratio of fuel production to oxidizer flow rates as the fuel grain regresses.

For its first hybrid motor attempt, WCC is using a commercial off-the-shelf motor produced by Contrail Rockets. Liquid nitrous oxide (laughing gas) is pumped into an upper chamber prior to launch. Once this tank is fully pressurized, the nitrous oxide becomes flammable. Prior to this fueling, the motor is inert. Upon ignition, a valve opens allowing the hot nitrous oxide to flow through a proprietary solid fuel, causing volatiles in its grain to ignite. The resulting high-pressure exhaust exits the nozzle providing the rocket’s thrust.  

The WCC team conducted four hybrid motor tests at the college’s Static Rocket Motor Test Facility. The first two tests resulted in failure due to an over-pressurization of the main fill line and battery problems.  

With these issues resolved and refinements made to the launch protocols, a third static test was conducted on January 11, 2020 that resulted in the team’s first successful ignition of a hybrid motor —and likely the first in Hawaii. Burn time for this M class motor was 4.2 sec. Its total impulse of 6,547 Ns is calculated to lift the rocket and payload to an altitude of 9,730 feet AGL.

A fourth test on February 22 also proved successful. On October 3, 2020 the WCC team conducted their 5th static hybrid motor test. The WCC rocketry team successfully launched its first hybrid rocket at Fall’s ARLISS 2021 competition.

collage of project Imua team photos


ESRA 2020-21 Documents

Technical Report 1 (WIP) (pdf)

Project Imua Entry Form (pdf)

 Milestones in the Development of the Hybrid Rocket

  • Nov. 17 2019 - The WCC team attemepted the first static test of the hybrid motor. Due to hardware issues, the fill lines burst due to over pressurization causing the motor to release its fuel, resulting in a failed ignition of the liquid fuel. The team was still able to test the ignition system succesfully.
  • The next Static Test has been rescheduled for December 14, 2019. Improvements to the fueling system have been made and we expect a succesful test.
  • Dec. 14 2019 - The WCC team attempted a second static test of the hybrid motor. Due to leaks from the previous & current tests, we lost a majority of our N2O gas before the tank could fill. In addition more gas was lost due to ignition system delays resulting in a failed test. Post test autopsy showed that everything worked properly and would have been successful had we not run out of gas. The next test will be Dec. 31, 2019.
  • Jan 4, 2020 - The Dec. 31st test was cancelled due to lack of N2O and has been rescheduled to take place on Jan. 11, 2019.
  • Jan 11, 2020 - WCC Team attempted a third static test of the hybrid motor and was successful. The M1575 Motor was attached to a steel truss frame, which was anchored to an 800lb cement block embedded in the ground, via multiple hose clamps, as well as a redundant retention line. The motor used 10 ohm resistors for its ignitors, and used 50/50 pyrodex for ignition. The ignition was achieved by using a 24V 5A power supply. We used an amber flashing light powered by a 12V battery for safety notification. The fueling process was controlled by an electronic solanoid valve which was powered by another 12V battery. We also fabricated an ignition switch board which insured that the rocket ignited safely. The motor test was filmed on two separate cameras. The videos will be available for viewing soon.
  • Jan 28, 2020 - The WCC team is currently waiting on parts to be delivered to begin assembly on the frame of the rocket. Construction of the quadcopter, which will be carried within Apophis and ejected during a test flight, has also begun. During this time a member of the WCC team also began calibrating and testing the rockets avionics section(Telemega V3 / Stratologger).
  • Feb 16, 2020- The WCC team successfully tested the Telemega V3 in a Executioner model rocket. The data shown in thi graph shows the maximum height achieved, maximum speed, max acceleration, as well as the 4 phases of a rocket launch (Boost, Coast, Droge Deployment, and Touchdown) and the over-all time of the launch itself.
    graph comparing time vs height
  • Feb 29, 2020 - On Feb. 22 the WCC team conducted their 4th static test of their hybrid motor and was sucessful for the 2nd time in a row. Members from the HCC team developed and tested a thrust plate to get a thrust curve readingfor the hybrid motor (Data wil be uploaded as it is made available).
    Video from a GoPro attached to the motor at ignition

    Video recorded on a cell phone remotely close by to the rocket at ignition

  • July 2020 - The avionics section for Apophis was succesfully tesed. On July 20, 2020, the team succesfully tested the GPS coding written by a previous member.
  • October 3, 2020 - The WCC team conducted their 5th static hybrid motor test which resulted in a success. A thrust curve was obtained and calculated a rate regression parameter for the overall thrust determination.
    Apophis Static Hybrid Motor Force vs. Time graph