Warming up the thruster that will ram LOHAN to glorious heights

Project team prepares to shove pocket rocket in toaster

Our audacious Low Orbit Helium Assisted Navigator (LOHAN) spaceplane project continues to advance on multiple fronts, and while Neil Barnes and Anthony Stirk put together the Special Project Electronic Altitude Release System (SPEARS) control board, we've been doing some more work on the Vulture 2 rocket motor heater set-up.

Click here for a bigger version of the LOHAN graphicTo summarise, we know a solid rocket motor will fire at altitude, but the effect of very low temperature on the thruster's ammonium perchlorate composite propellant (APCP) is unknown.

To launch a pre-emptive strike on this potential problem, we decided to heat the motor on the ascent phase of the mission, and got our hands on a space-grade Polyimide Thermofoil flexible heater.

The heater's effective area is 300.257 cm2, and its resistance is 64Ω. At 12V it draws 0.1875A and pumps out 2.24W, which translates to a watt density of 0.0078W/cm2. We hooked it up to a 1300mAh Lithium Polymer (LiPo) battery (11.1V nominal)...

The heater test rig, with battery, watt meter, temperature sensor, heater and insulation

...and the first results were encouraging. Here's how the LOHAN toaster performed when sandwiched between two sheets of styrofoam:

Graph of our first heater test, between styrofoam sheets

Biting the hand that feeds IT © 1998–2017