Long March 1D

The Long March 1D (CZ-1D) was a member of China's Long March rocket family, developed by the China Academy of Launch Vehicle Technology (CALT) during the 1990s. It was an improved version of the Long March 1, itself derived from the Dong Feng-4 (DF-4) intercontinental ballistic missile. The primary purpose of the Long March 1D was to test reentry vehicle warheads for the DF-31 missile, though it was also offered for commercial satellite launch applications.

Development and Design

During the 1990s, CALT developed an enhanced version of the DF-4 to test reentry vehicle warheads for the DF-31 program. This development was subsequently offered commercially as the Long March 1D. Key modifications from the original Long March 1 included:

• First stage: An improved DF-4 first stage using a new version of the YF-2B engine, with propellants switched to UDMH/N₂O₄ (unsymmetrical dimethylhydrazine and nitrogen tetroxide) for improved performance.
• Second stage: Replacement of the original DF-4 second stage motor (YF-3A) with the Long March 4 third stage engine, the YF-40 (two engines).
• Inter-stage: A new inline inter-stage replaced the existing tapered connector between the second and third stages, allowing an additional 70 cm diameter to be added to the third stage skirt and enabling the addition of reaction control system (RCS) to the third stage.
• Third stage: A new third stage with a new solid rocket motor, the FG-36, and an optional RCS.
• Guidance: A new computer inertial guidance system enabling three-axis stabilization of the third stage for improved precision.

Specifications

Launch History

The Long March 1D flew three suborbital missions from Taiyuan Launch Center (LC-1), with two successes and one failure:

The design did not receive strong commercial reception and was ultimately used only for reentry vehicle tests. The Long March 1D was retired after its final mission in 2002.