Rockets of Today

ROKOT (Рокот) — Russia, 1994

Though derived from an ICBM, this is Russia’s first for-profit commercial rocket. Launches are sold by a consortium named Eurockot. It has three stages, all using UDMH hypergolic fuel. The first stage has four small Energomash engines, one of which is tweaked to feed hot gas into the reservoir used to pressurize the fuel tanks — an approach previously used on the second stage of the Proton. The Rokot’s second stage has a nongimballed motor with vernier thrusters. The third stage which enables it to reach orbit is a Briz (Бриз, “breeze”) — a model which also sometimes used as a kick stage atop a Proton or Angara in a version with larger tanks than are used here. On the Rokot I believe it is non-optional, and the first two stages cannot reach orbit. (ICBMs reach speeds around 75% or more of orbital, depending on how intercontinental they really are, and the UR-100N / SS-19 needed both stages for that.) The word “rokot” means “rumble” — it’s named after the noise it makes.

A variant called Strela (Стрела, “arrow”) is not commercialized — closer to its ICBM roots, they say. It uses a different third stage and has a somewhat lower capacity.

The original plan was for the Rokot to be retired in favor of the single-stick Angara. But now the original Rokot is retired early for an unrelated reason, as it depended on guidance hardware from Ukraine which is no longer available to Russian buyers. Efforts are underway to get funding for an all-Russian Rokot 2, as the wait for the Angara to enter regular service drags on.

Rokot: mass 107 t, diam 2.5 m, thrust 3100 kN, imp 2.8 km/s, staged combustion (UDMH), payload 1.9 t (1.8%), cost $10M/t?, record 29/2/3 (may be final).