Chinese Long March 2D’s 50th launch lofts latest Gaofen-9 satellite

by Rui C. Barbosa

A new satellite on the Gaofen-9 remote sensing series was orbited by China on Wednesday. A Long March 2D launched the Gaofen-9 (04) at 04:01:54 UTC from the Jiuquan Satellite Launch Center’s LC43/94 complex.

This was also the 50th launch of the Long March-2D launch vehicle and the 342nd launch of the Long March launch vehicle family.

The Gaofen-9 is a series of optical remote-sensing satellite that operates together with other satellites from the Gaofen series to form an Earth observation system.
As usual, according to the official Chinese media, the satellite will be used for land surveys, city planning, land right confirmation, road network design, crop yield estimation and disaster prevention and mitigation.

Gaofen (“High Resolution”) is a program of civilian Earth observation satellites developed and launched for the state-sponsored program China High-definition Earth Observation System (CHEOS).

It is expected that a new Gaofen-9 satellite, Gaofen-9 (05) should be orbited from Jiuquan until the end of August.

The first Gaofen-9 was orbited on September 14, 2015, by a Long March-2D rocket from Jiuquan. All following launches on the series were launched from this launch site using the LM-2D on May 31 and June 17, 2020.

Together with the Gaofen-9 (04) China also orbited a Tsinghua developed gravity and atmospheric science satellite, Tsinghua Kexue Weixing.

The research objective of this scientific satellite project is based on the study of the gravity field. For this study, the satellite needs a precise orbit using GPS signals to achieve centimeter-level positioning (5 cm precision orbit).

The primary goal of the Tsinghua Science Satellite Project is to receive on-orbit measured data for technical verification. This data includes atmospheric density and gravity field data.

The Long March 2D (Chang Zheng-2D) launch vehicle is a two-stage rocket developed by the Shanghai Academy of Spaceflight Technology. It is mainly used to launch a variety of low earth orbit satellites.

The CZ-2D can launch 1,300 kg of cargo into a 645 km SSO.
It shares the same first and second stages as the Chang Zheng-4, although the second stage sports an improved equipment bay.

At launch, the Long March 2D develops 2961.6kN of engine thrust, with the first stage powering the YF-21C engine that consumes 183,200 kg of N2O4 / UDMH. The rocket has a lift-off mass of 232,250 kg.

The second stage has a launch mass of 39,550 kg, with its YF-24C cluster engine running off 35,550 kg of N2O4 / UDMH.

The Long March 2D can use two types of fairings depending on the cargo. Type A fairing has a 2.90 meters diameter and the Type B fairing with a diameter of 3.35 meters.

The Long March 2D conducted its maiden flight on August 9, 1992 from the Jiuquan Satellite Launch Center – orbiting the Fanhui Shei Weixing FSW-2-1 (22072 1992-051A) recoverable satellite.

The Jiuquan Satellite Launch Center, in Ejin-Banner – a county in Alashan League of the Inner Mongolia Autonomous Region – was the first Chinese satellite launch center and is also known as the Shuang Cheng Tze launch center.
The site includes a Technical Centre, two Launch Complexes, Mission Command and Control Centre, Launch Control Centre, propellant fuelling systems, tracking and communication systems, gas supply systems, weather forecast systems, and logistic support systems.

Jiuquan was originally used to launch scientific and recoverable satellites into medium or low earth orbits at high inclinations. All Chinese crewed missions are launched from this site.

The LC-43 launch complex, also known as the South Launch Site (SLS) is equipped with two launch pads: 91 and 94. Launch Pad 91 is used for the manned program for the launch of the Long March-2F launch vehicle (Shenzhou and Tiangong).

Launch Pad 94 is used for uncrewed orbital launches by the Long March-2C, Long March-2D and Long March-4C launch vehicles.

Other launch zones at the launch site are used for launching the Kuaizhou, the CZ-11 Chang Zheng-11 and commercial launch vehicles using solid rocket motors.

The first orbital launch took place on April 24, 1970 when the CZ-1 Chang Zheng-1 rocket launched the first Chinese satellite, the Dongfanghong-1 (04382 1970-034A).

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