Candlewax Rockets: A Green Alternative for In-Space Propulsion

Space Exploration Initiative

The Space Enabled Research Group is exploring the potential of using beeswax and candle wax as potential fuels for satellites in space. Beeswax and candle wax are both low cost, non-toxic materials that can be accessible to teams around the world. 

Previous research at Stanford University and beyond has shown that wax-based hybrid rocket propellants, including paraffin (common candlewax) and beeswax show promise as high-performing hybrid rocket propellants for chemical propulsion systems. Wax is safe for humans to handle, can be managed with simple equipment and is low cost (less than $4/kg); these characteristics make waxes well-suited for widespread adoption for launch and in-space applications. Their benign nature compared to the toxicity and carcinogenicity which characterize currently-used propellants, such as hydrazine and nitrogen tetroxide, make paraffin an especially strong candidate for new entrants to the propulsion community.

Space Enabled is exploring whether wax can be used as a propellant to de-orbit satellites which would otherwise become space debris. In addition, Space Enabled is studying opportunities to perform in space the manufacturing of wax into the shape that is ideal to be used for fuel, a hollow tube with an opening in the middle to allow oxidizer to pass through.  The ability to manufacture wax into a fuel grain in space could overcome concerns that brittle wax fuel grains might crack or crumble during launch. Wax is also promising as a propellant for satellites because of its thermal properties. Wax has previously been used as a thermal insulator on spacecraft. Space Enabled envisions repurposing wax insulation as fuel, thus providing examples of reuse and multiple purpose materials on spacecraft. This is part of a larger vision to work toward future material lifecycles in space that emphasize reuse and recycling.

Space Enabled has demonstrated through experiments that there is likely an advantage to manufacturing wax fuel grains in microgravity as compared to the gravity environment on Earth. In the microgravity environment, Space Enabled has found that wax can be cast into a fuel grain at lower rotation rates than in the laboratory. Space Enabled has performed three reduced gravity plane flights to find this preliminary results. Additional tests are planned for suborbital flights and an experiment on the International Space Station.


Space Enabled Research Group