Propellant

Today’s spacecraft use rockets and rockets use large quantities of propellant.

As propellant blasts out of the rocket in one direction, it pushes the spacecraft in the other.

In a solid rocket, the propellants are mixed together and packed into a solid cylinder. Under normal temperature conditions, the propellants do not burn; but they will burn when exposed to a source of heat provided by an igniter. Once the burning starts, it proceeds until all the propellant is exhausted.

In-space electric propulsion can reduce the amount of fuel, or propellant, needed by up to 90% compared to chemical propulsion systems.

Then they backed the membrane with a gel matrix containing a perfluorocarbon (PFC) propellant and fluorescent "nanobullets" about a micron wide, and hit it with ultrasound.