DENAKIV - Build

Project Overview

Project Top Hat (or DENAKIV) is a cold gas thruster system capable of hovering 3 feet in the air for at least 5 seconds. The primary objective of this project is to develop a control algorithm to mimic the level of control demonstrated by the MKV-L developed by Lockheed-Martin. 

Build Overview

Top Hat is propelled by four nitrogen cold gas thrusters, each capable of around 2 pounds of thrust. The thrusters have an inlet pressure of close to 300 psi and are 3D printed out of PLA. These nozzles are mounted to an acrylic base and receive gas from a manifold at the center of this base. The entire system is tethered to a test stand which supplies the nitrogen. Each cold gas thruster is pulsed using a high pressure solenoid valve. 

Surrounding the manifold are four 3D printed mounts through which the Arduino, relays, and other electronics are mounted. The battery is located above the manifold in between the four mounts. 

Project Challenges

One of the most difficult challenges of this project is finding a safe, high energy propellant that can reliably reignite while also not burning too hot. Top Hat uses cold gas due to its ease-of-use, however, these systems are incredibly inefficient, preventing the use of onboard tanks. 

The long term goal of this project is to use hypergolic propellants, such as nitric acid and turpentine or a nitromethane - nitrous oxide combination (not hypergolic, but highly volitile), to provide the thrust and control needed to mimic a real kill vehicle. Hypergols reignite easily and their high energy density allows small, lightweight tanks to be installed onboard. This raises some obvious safety and design concerns (fueling the tanks safely and designing a thruster for more "tame" hypergolic propellants). 

Another challenge is designing a control algorithm through the simple Arduino architecture. Using an inertial measurement unit, it's possible to create a loop that pulses the thrusters as the vehicle begins to roll in the wrong direction.