Hold-down and release mechanism (HDRM)

We developed ARMER, a reusable hold-down and release mechanism for small spacecraft and payloads, with mentors from NASA's Jet Propulsion Laboratory. It holds a deployable in place without continuous power, then releases it on command through mechanically and electrically redundant actuation. The mechanism can be reset for repeated testing, with no consumable parts.

How it works

The mechanism uses two rotating, over-center latches and a deployable pin with a pivoting anchor. This arrangement provides mechanical redundancy during release. Electric actuators with position feedback drive the latches, which stay locked when power is removed and release the deployable within a fraction of a second.

We designed the HDRM to be reset between tests without replacing parts. It accepts pyrotechnic trigger signals as well as digital commands. The digital interface also supports self-diagnostics, usage logs and real-time status reporting to a flight computer.

Development

Our team was five engineering and computer science students from NYU Abu Dhabi’s Engineering Design Studio. We worked with mentors through JPL’s University Crowdsourcing Initiative (JUCI) to define the operating requirements and system characteristics.

We used multi-domain simulations to work through the design before building the first functional prototype. Fabricators in several countries machined and 3D-printed its titanium and stainless steel components.

Flight on Haloship

In June 2023, we flew two identical HDRMs on Haloship at the Spaceport America Cup, with a target altitude of 10,000 feet. They held the rocket sections together through launch, then released them to deploy the drogue and main parachutes.

The flight let us test the mechanisms under aerodynamic and structural loads, including both separation events. Haloship placed second out of 158 teams for the Dr. Gil Moore Award for Innovation, with the reusable structure and non-explosive recovery system central to the design.