NIAGARA FALLS, N.Y., March 23, 2011 /PRNewswire/ -- AMPAC-ISP CORP., American Pacific Corporation's (Nasdaq: APFC) wholly-owned in-space propulsion subsidiary (AMPAC-ISP), reported that their LEROS 1b bipropellant engine (LEROS 1b) fired for nearly fifteen minutes in the early hours on March 18, 2011 to slow the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft and place it into orbit around Mercury. The orbit insertion firing slowed the spacecraft by more than 1,900 miles per hour, with the rendezvous taking place 96 million miles from the Earth. The firing consumed nearly one third of the propellant that the spacecraft carried at launch. The LEROS 1b performed five deep space maneuvers in the six and one-half years since launch, to line up MESSENGER for the final orbit insertion maneuver. Operational data transmitted back to the Earth has confirmed successful orbit insertion by the LEROS 1b. MESSENGER was launched on August 3, 2004, and has traveled nearly five billion miles. MESSENGER will spend the next year imaging Mercury, as well as gathering data on its composition and atmosphere.

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The LEROS 1b was developed and is manufactured at AMPAC-ISP's Westcott UK division, with final testing at their Niagara Falls, NY facility. The LEROS 1b is a 150 pound thrust bipropellant engine that operates on hydrazine and nitrogen tetroxide propellants, combining high thrust with high specific impulse to provide thrust margin for heavy payloads and deep space probes. The LEROS 1 series has been used for a variety of interplanetary missions including Mars Global Surveyor, Mars Odyssey and the NEAR asteroid mission. More than seventy (70) LEROS 1 series engines have been delivered and flown successfully.

"AMPAC-ISP is proud to have played a part in this historic event, putting the first artificial satellite into orbit around Mercury, and we look forward to the important data that MESSENGER will return," said Robert Huebner, American Pacific Corporation, Vice President – AMPAC-ISP. "The successful firing of the LEROS 1b after more than six years in operation demonstrates the reliability of the engine and confirms industry confidence in the LEROS 1 engine series for deep space exploration."

The LEROS 1b will play a critical role in the next interplanetary NASA mission, JUNO, set to launch in August 2011.

ABOUT AMPAC-ISP CORP.

AMPAC-ISP Corp. (AMPAC-ISP), a wholly-owned subsidiary of American Pacific Corporation, manufactures monopropellant and bipropellant liquid propulsion systems and thrusters for satellites, launch vehicles and interceptors. Additionally, AMPAC-ISP designs, develops and manufactures high performance valves, pressure regulators, cold-gas propulsion systems, and precision structures for space applications, especially in the European space market. Additional information about us can be obtained by visiting our web site at www.ampacisp.com.

AMPAC-ISP's European operations are headquartered in Dublin, Ireland and its manufacturing facilities are in the United Kingdom and Ireland. Additional information about AMPAC-ISP Europe can be obtained by visiting www.ampacispdublin.eu.

ABOUT AMERICAN PACIFIC CORPORATION

American Pacific Corporation (AMPAC) is a leading custom manufacturer of fine chemicals, specialty chemicals and propulsion products within its focused markets. We supply active pharmaceutical ingredients and advanced intermediates to the pharmaceutical industry. For the aerospace and defense industry we provide specialty chemicals used in solid rocket motors for space launch and military missiles. AMPAC also designs and manufactures liquid propulsion systems, valves and structures for space and missile defense applications. We produce clean agent chemicals for the fire protection industry, as well as electro-chemical equipment for the water treatment industry. Our products are designed to meet customer specifications and often must meet certain governmental and regulatory approvals. Additional information about us can be obtained by visiting our web site at www.apfc.com.

SOURCE American Pacific Corporation