Early British solid propellants
The first solid propellants were homogeneous propellants obtained by press extrusion (EDB, Extruded Double Bases) or by casting (CDB, Cast Double Bases). Plastic propellants were produced since 1938, prior to the opening of hostilities. After the war, work was directed towards producing plastic composite solid propellants employing ammonium perchlorate and picrate and polyisobutylene binder.
17 inch British solid motors
Early British Army SAMs (Red Shoes, later Thunderbirds) were powered by solid propellant sustainers, 17 inches (43.2 cm) in diameter. After some liquid propelled prototypes, the Red Shoes vehicles were successively propelled by Ratcatcher, Smoky Joe, Elkhound, Wolfhound and Albatross. The motor intended for the upper atmosphere sounding rocket (which later become Skylark) was created starting from the experience gained with these series. Raven, obtained by welding three Smoky Joe tubes together, contained 840 kg of propellant (the later versions reached 1020 kg). Cuckoo, with 180 kg of propellant, was half less long than Smoky Joe whereas Goldfinch, with approximately 310 kg, had the same size. The last of the series, Rook, designed for fast burning, was as long as Raven and carried 880 kg of propellant.
Early French solid propellants
The first solid propellants were homogeneous propellants of which the grains were pressed (SD) or cast (Epictète) charges. In early Sixties, the composite propellants allowed the construction of wider grains with higher specific impulse. Three categories of composite propellants appeared successively in France: Plastorgols with polyvinyl chloride binder, Isorgols with polyurethane binder and Butargols with polybutadiene binder. Each of them existed in two versions: without aluminium additive (Plastolite, Isolite and Butalite) and with aluminium additive (Plastolane, Isolane and Butalane).
560 mm French solid motors
The Vesuve grains, 550 mm in diameter (motors are of about 560 mm) were first stage boosters for SAMs such as the ECAN Masurca, the Matra R422 and R431 and the SNCASE SE4400. The last three mentioned used the SEPR 732 version (470 kg of Plastolite, about 880 kNs in 4.5 s) that later became the motor of the SEREB VE9 rocket. A SEPR 734 version (1020 kNs in 4.5 s) was also developed for the R422. It was then used as first stage of the ONERA Antares rocket and as the booster of the Nord Aviation Vega experimental ramjet. This improved Vesuve also boosted the last ONERA Statex ramjets.
A technological program, led in 1957-58 by Service des Poudres, ONERA and SEPR, resulted in the development of an experimental solid motor burning for 15 to 20 s and using a 550 mm grain named Stromboli. This grain gave birth to the SEPR 737 motor of the SEREB VE10 rocket and SEPR 738 of the ONERA Stataltex ramjet vehicle. Largest of the series was the SEPR 739 (1240 kg of propellant, 2850 kNs in 20 s) that equipped the first stage of the Berenice, Tacite, Titus and Tibere rockets - as well as the 2nd stage of Tibere - and boosted the X-422 ramjet. The SEPR 740 (738 kg of propellant, 1650 kNs in 18 s) was the second stage of Berenice and Titus. The Dragon, Dauphin and Eridan sounding rockets used a solid motor loaded with a 2-m long Stromboli grain named S2 (686 kg of propellant, 1380 kNs in 16 s). During the 1960s, Plastolane propellant replaced Plastolite.
Stromboli launch log
IRIS (Italian Research Interim Stage)
This solid-motor was developed by Alenia as a perigee stage for launching 600 to 950 kg payloads from the Space shuttle. The IRIS is composed primarily of two elements: the reusable launch platform (ESA) including a spinning table (45-100 rpm) and the consumable solid-rocket motor (SRM). This BPD motor is 1.94 m long (with the nozzle), 1.30 m in diameter, and weighs 1721 kg including 1574 kg of propellant (HTPB) in nominal version or 1328 kg in reduced version (-25% of propellant). It provides a total impulse of 4490 kNs in 79 sec in the first case, 3370 kNs in 63 sec in the second. The Challenger disaster reduced the IRIS career to only one launching. It had also been proposed like upper stage for the Vega launcher (1st version).
This solid-motor was developed by SEP/BPD/MAN as an apogee stage for geostationary satellites. It was also proposed as an upper stage for the Skylark 17 rocket. It is a 1.52 m length engine, 77 cm in diameter, weighing 530 kg including 490 kg of propellant, and capable of providing approximately 1412 kNs in 44 seconds.