Specific momentum:

4. Specific momentum: Units of are seconds

7. The LR87is a liquid rocket engine, similar in concept to the XLR99 and S-3D, but with significant differences. It is a fixed thrust engine that cannot be throttled, and it is not restartable in flight. The propellants are storable; they do not boil at normal temperatures as liquid oxygen does so they can remain in their tanks for extended periods of time. The engine delivers approximately 430,000 lbs. of thrust using Aerozine-50 (fuel) that ignites on contact with nitrogen tetroxide (oxidizer). Propellants such as these are termed "hypergolic."

8. The S-3D rocket engine powered the Jupiter intermediate range ballistic missile (IRBM), delivering 150,000 pounds of thrust for approximately 2.5 minutes. Development of the basic S-3 engine began in late 1955 and a test model was delivered to the Army Ballistic Missile Agency--then responsible for Jupiter development--in July 1956 for installation and test firing. The first production S-3 was delivered two months later

9. H-II Launch Vehicle • The H-II launch vehicle, the central rocket in Japan's space program, with the capability to launch a two-ton class satellite into geostationary orbit, is a two-stage rocket that was developed with Japanese independent technology in all stages. In addition to geostationary satellite, it can also be used to launch payloads into low and medium-altitude orbits. For greater economy, it is possible to launch simultaneously two geostationary satellites weighing about one ton each. The 1st stage has a large, high-performance liquid oxygen/liquid hydrogen engine known as the LE-7. Newly developed for the H-II launch vehicle, it offers propulsion of approximately 110 tons in a vacuum. The 2nd stage uses the LE-5A engine. This reignitable engine offers higher performance and reliability than the LE-5 engine developed for the H-I launch vehicle. The guidance system employs an inertial guidance method, a further improvement on H-I development results. • results.

10. A Japanese team has recovered the main engine from an H-2 rocket that crashed into the Pacific Ocean minutes after launch in mid-November, Japanese space agency officials reported Tuesday. The LE-7 engine was recovered January 23 by a salvage ship in a joint operation between Japan's National Space Development Agency (NASDA) and the Japan Marine Science and Technology Center (JAMSTEC). The engine was hauled to the surface after a remotely-operated submersible attached a cable to the engine, sitting on the ocean floor 3,000 meters (10,000 feet) below the surface 380 km (235 mi.) northwest of the Ogasawara Islands. Workers examine the LE-7 engine retrieved from the ocean floor. Japan Ends H-2 Rocket Program

11. Test Firing of Ambitious Indian Rocket Engine AbortedNew Delhi (AFP) February 17, 2000 - India's first test firing of its locally built and most ambitious rocket engine has failed, a government statement said Thursday. The 7.5-tonne engine, using liquid hydrogen and liquid oxygen, was ignited at the Liquid Propulsion Systems Centre at Mahendragiri in southern Tamil Nadu state on Wednesday, the statement said. "However, the test had to be aborted at 15 seconds instead of the planned duration of 30 seconds," it said.

13. Cape Canaveral • Vandenberg • Kourou • Tyuratam • Plesetkst

21. The Saturn V was the largest operational launch vehicle ever produced. Standing over 363 feet high with its Apollo Spacecraft payload, it produced over 7.5 million pounds of thrust at lift-off.