The CZ-3B is very similar to the CZ-3A but with four liquid-fuel strap-on boosters of the type used by the CZ-2E. This addition will nearly double the GTO payload capacity to 4.8 metric tons and provide a 12 metric ton capacity to LEO.
The space program of the People's Republic was again hit hard in 1996 when two of its three commercial missions failed. Having seemingly recovered from the loss of a Long March (Chang Zheng) 2E (LM-2E) early in 1995, which killed six civilians, with the subsequent successful launch of two LM-2Es, China's efforts to establish itself as a major player in the commercial space launch market were dealt another blow when a Long March 3B (LM-3B), on its first flight, exploded 20-25 seconds after takeoff from the Xichang Satellite Launch Center on 14 February 1996. The accident destroyed the $125-million Intelsat 708 satellite which was to be used primarily for direct broadcast satellite (DBS) services to Latin America. At least six people were killed and 57 injured. The launch was the second in a series of 10 Intelsats (the first by a Long March rocket) covered under an insurance premium of $185 million purchased by Intelsat in 1994. Premiums for the three Long March launches covered by this package had been set at 13 percent. The loss cost the insurers $205 million.By 28 March 1996 the Chinese investigation and analysis of the failure determined the cause to be a malfunction of the vehicle's inertial guidance system two seconds after ignition. The failure in the inertial reference system was caused by a failure of output from one of the power modules in the electronic box of the platform. A series of measures were taken to resolve the problem, which were implemented on the LM-3A and LM-3B. At the request of international insurance underwriters and overseas customers, on 14 April 1996 an Independent Review Committee [IRC] was established to conduct an independent review of China's failure investigation findings. The IRC consisted of six experts from the United States, Britain and Germany.
On August 20, 1997, the second flight of LM-3B successfully sent the Philippine Agila 2 MABUHAY satellite into GTO, and on October 17, 1997 the third flight of LM-3B sent the APSTAR-IIR satellite into orbit.