by the application of electric current. Unlike conventional rocket motor propellants that are difficult to control and extinguish, ESPs can be ignited reliably at precise intervals and durations. It requires no moving parts and the propellant is insensitive to flames or electrical sparks. Hobby and amateur rocketry Solid propellant rocket motors can be bought for use in model rocketry; they are normally small cylinders of black powder fuel with an integral nozzle and optionally a small charge that is set off when the propellant is exhausted after a time delay. This charge can be used to trigger a camera, or deploy a parachute. Without this charge and delay, the motor may ignite a second stage (black powder only). In mid- and high-power rocketry, commercially made APCP motors are widely used. They can be designed as either single-use or reloadables. These motors are available in impulse ranges from "A" (1.26 Ns– 2.50 Ns) to "O" (20.48 kNs – 40.96 kNs), from several manufacturers. They are manufactured in standardized diameters and varying lengths depending on required impulse. Standard motor diameters are 13, 18, 24, 29, 38, 54, 75, 98, and 150 millimeters. Different propellant formulations are available to produce different thrust profiles, as well as special effects such as colored flames, smoke trails, or large quantities of sparks (produced by adding titanium sponge to the mix). Use Sounding rockets Almost all sounding rockets use solid motors. Astrobee Black Brant S-310, S-520 Skylark (rocket) Terrier-Orion, Terrier-Malemute VSB-30 Missiles Due to reliability, ease of storage and handling, solid rockets are used on missiles and ICBMs. Air-to-air missiles: AIM-9 Sidewinder Ballistic missiles: Jericho, Sejjil ICBMs: LGM-30 Minuteman, UGM-133 Trident II, LGM-118 Peacekeeper, RT-2PM Topol, DF-41, M51 SLBM Orbital rockets Solid rockets are suitable for launching small payloads to orbital velocities, especially if three or more stages are used. Many of these are based on repurposed ICBMs. Scout Athena Mu Pegasus Taurus Minotaur Start-1 PSLV - alternating solid and liquid stages Shavit Vega Long March 11 OmegA Larger liquid-fueled orbital rockets often use solid rocket boosters to gain enough initial thrust to launch the fully fueled rocket. Delta II Titan IV Space Shuttle Space Launch System Ariane 5 Atlas II Atlas V (optionally 1-5 boosters) Delta IV (optionally 2 or 4 boosters) H-IIA, H-IIB PSLV - optional solid boosters to lift heavier payloads GSLV Mk III Solid fuel is also used for some upper stages, particularly