Long March 2D launches LKW-4

by Rui C. Barbosa

Returning to orbital launch activity after the traditional festivities of the Spring Festival, China launched a new remote sensing satellite on Saturday. Launch took place at 07:10 UTC via a Long March 2D launch vehicle orbiting a new satellite in the Ludikancha Weixing (LKW) series, also known as ‘Land Surveying’. The launch of Ludikancha Weixing-4 took place from the 94 Launch Platform at the LC43 Launch Complex from the Jiuquan Satellite Launch Center (JSLC).

As per usual for the Chinese media, this spacecraft is once again classed as a new remote sensing bird that will be used for remote sensing exploration of land resources.

As was the case in previous launches of this series, analysts believe this class of satellites is used for military purposes.

Previous satellites on the series were the LKW-1 (43034 2017-077A) that was launched on December 2, 2017; the LKW-2 (43080 2017-084A) that was launched on December 23, 2017; and the LKW-3 (43146 2018-006A) launched on January 13. All satellites were orbited by Long March-2D launch vehicles from the Jiuquan Satellite Launch Center.

Before the launch of Ludikancha Weixing-1, and when the NOTAMs were announced for this mission, observers of the Chinese space program were expecting the launch of the Yaogan Weixing-31 satellite, and more precisely the launch of a new electro-optical imaging satellite.

CCTV screenshot showing ground stations

Analysts were already surprised by the launch of the YG-30-01 Yaogan Weixing-30-01 triplet on September 29, 2017 (and subsequent similar missions on November 24, 2017; December 25, 2017 and January 25, 2018), so the designation ‘Ludikancha Weixing’ came as a surprise.

As per usual for China, this kind of generic designation is often used hide the military purpose of some missions. In this case, the Ludikancha Weixing appears to be related to the electro-optical imaging satellites that were previously launched under the cover name of the Yaogan Weixing missions.

Namely, with a perigee of 489 km, apogee of 502 km and orbital inclination of 97.4 degrees, the Ludikancha Weixing satellites appears to be related to the Jianbing-10 series of CAST (China Academy of Space Technology)-developed second generation electro-optical imaging satellites.

We will need to wait and see if the deployment of the Ludikancha Weixing satellites follow a similar pattern that was used with the deployment of the low-orbiting optical imaging reconnaissance satellites launched under the Yaogan Weixing series to establish a ‘definite’ conclusion about the true nature of this hexagonal shaped satellites.

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

The development of LM-2D was started in February 1990. From 2002, to meet the demand of SSO satellites, the payload fairing of 3350mm in diameter and attitude control engine for the second stage have been successfully developed; and the discharge of remaining propellant and de-orbit of the second stage have been realized. This launcher is mainly used for launching LEO and SSO satellites.

It is characterized by high reliability, wide application and mature technology.

The LM-2D can launch a 1,300 kg cargo in a 645 km SSO. The rocket is 41.056 meters long and the first, second stages and payload fairing are all 3.35 meters in diameter.

The first stage is the same of the Long March-4.

The Long March used for this mission

The second stage is based on LM-4 second stage with an improved equipment bay. Lift-off mass is 232,250 kg, total length 41,056 meters, diameter 3.35 meters and fairing length 6.983 meters. At launch, it develops 2961.6 kN engine thrust.

The first stage has a 27.910 meter length with a 3.35 meter diameter, consuming 183,200 kg of N2O4 / UDMH (launch mass of the first stage is 192,700 kg). Equipped with a YF-21C engine capable of a ground thrust of 2,961.6 kN and a ground specific impulse of 2,550 m/s. Burn time is 170 seconds.

The second stage has a 10.9 meter length with a 3.35 meter diameter, launch mass of 39,550 kg and consuming 45,550 kg of N2O4 / UDMH. Equipped with a YF-24C cluster engine with a main engine vacuum thrust of 742.04 kN and a vernier engine with a vacuum thrust of 47.1 kN (specific impulses of 2,942 m/s and 2,834 m/s, respectively).

The LM-2D can use two types of fairings depending on the cargo. Type A fairing has a 2.90 meters diameter (total launch vehicle length is 37.728 meters) and Type B fairing with a diameter of 3.35 meters – total launch vehicle length is 41.056 meters.

Long March 2D launch – photo from Chinese media.

Launch profile of the Long March-2D starts with engine ignition at 1.2 seconds before lift-off. Pitch over maneuver happens at 12 seconds into the flight and the end of the first stage ignition occurs at two minutes 33 seconds. Stage separation and second stage ignition occur one second later. At 3 minutes 34 seconds the two parts of the fairing separate from the second stage.

Second stage main engine cut-off takes place at 4 minutes 21 seconds and second stage Vernier engines cut-off takes place at 9 minutes and 10 seconds. Nominally payload separation takes place three seconds later.

The first launch of the LM-2D was on August 9th, 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 Launch Site – Photo via Chinese Media

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. It is also the place from where all the Chinese manned missions are launched.

The LC-43 launch complex, also known as 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 unmanned 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, Kaituo and the Long March-11 solid propellant launch vehicles.

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

Next in line for China will be the launch of a new pair of navigation satellites from the Xichang Satellite Launch Center, Sichuan province. The launch is expected to take place around March 26 using a Long March-3B/Y1 launch vehicle. The Yuanwang-3 space tracking vessel that will support this launch departed is home harbor on March 12. The ship will also be used to support the launch of the DFH-4 based APStar-6C communications satellite currently scheduled for April 21.

China is also preparing the launch of the PRSS-1 (Pakistan Remote Sensing Satellite) that will take place from the Taiyuan satellite Launch Center using a Long March-2C/SMA, but at this time the schedule of the launch activities related to this mission is uncertain.

A Long March-11 rocket is also scheduled to launch two Zhuai-1 satellites at the end of March or early April. Launch will take place from Jiuquan and a total of five satellites will be on board.

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