Long March 2D lofts Gaofen-9

by Rui C. Barbosa

A Long March 2D launched the Gaofen-9 (02) remote sensing satellite on Sunday, as China begins to ramp up its 2020 launch schedule. The launch took place at 8:53 UTC from the LC43/94 launch complex at the Jiuquan Satellite Launch Center, Inner Mongolia. The HEAD-4 satellite rode to orbit as a co-passenger.

The new Earth observation satellite is equipped with a high-resolution Earth observation system. It uses a microwave remote sensing system with ground cell resolution up to the sub-meter level, to be mainly used in land census, urban planning, land rights, road network design, crop estimation and disaster prevention and mitigation, and other fields.

The satellite will work together with other Gaofen satellites to form an Earth observation system with high resolution and high positioning accuracy, which will help promote international sci-tech industrial cooperation through data sharing and support the Belt and Road initiative.

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

In May 2010, China officially initiated the development of the CHEOS system, which is established as one of the major national science and technology projects.

The Earth Observation System and Data Center of China National Space Administration (EOSDC-CNSA) is responsible for organizing the construction of the CHEOS that is near-real-time, all-weather, global surveillance network consisting of the satellite, stratosphere airships, and aerial observation platforms.

The Earth Observation System and Data Center, China National Space Administration was established in March 2010.

The Center is principally responsible for organizing and implementing as well as managing CHEOS. It is also responsible for EO application services, commercial development, technology consultant and international cooperation.

By following an arrangement of integral observation from space, air and ground, the CHEOS is developing a space-based system, near-space system, aerial system, ground system and application system.

This is to create Earth observation at a high temporal, spatial and spectral resolution, which is making good progress.

To meet the strategic demands of the national economic development and social progress, the initial plan involved five satellites.

Gaofen-1 employed1. a CAST2000 bus, configured with one 2 meter panchromatic / 8 meter multi-spectral camera and one 16m multispectral medium-resolution and wide-view camera.

The satellite integrates imaging capacity at medium and high spatial resolution and with large swath, with a designed lifespan of over five years. It was launched on April 26, 2013.

Gaofen-2 employed a CS-L3000A bus, configured with one 1 meter panchromatic/4m multi-spectral camera, with a designed lifespan of over 5 years. The satellite was launched on August 19, 2014.

Designed by CAST (China Academy of Space Technology), Gaofen-3 employs the CS-L3000B bus configured with multi-polarized C-band SAR at meter-level resolution. The satellite had a designed lifespan of eight years and will mainly be used by the State Oceanic Administration (SOA) of China. GF-3 was launched on August 9, 2016.

Gaofen-4 was developed by CAST and is based on the new GEO remote-sensing satellite bus. It has an orbital mass of 4,600 kg, and was designed for a lifespan of 8 years. The satellite was placed into orbit by a Long March-3B launch vehicle from the Xichang Satellite Launch Centre on 29 December 2015.


Gaofen-5 employs the SAST5000B bus and is configured with six types of payloads, including visible and short-wave infra hyperspectral camera, spectral imager, greenhouse gas detector, atmospheric environment infrared detector at the very high spectral resolution, differential absorption spectrometer for atmospheric trace gas, and multi-angle polarization detector.

It is designed for 8 years and was launched on May 8, 2018, using a Long March-4C rocket from Taiyuan.

A Long March-2D orbited the Gaofen-6 satellite out of Jiuquan on June 2, 2018. This was an optical satellite similar to the Gaofen-1, but using a different instrument suite, consisting of a 2/8 m resolution panchromatic/hyperspectral camera with an image swath of >90 km and a 16 m resolution wide-angle camera with an 800 km image swath. Both cameras use a three-mirror anastigmat telescope. Both covers visible light to NIR bands.

On June 26, 2015, China launched the Gaofen-8 satellite. Developed by the China Aerospace Science and Technology Corporation (CASC), the satellite is part of a civilian program whose aim is to facilitate climate surveying, disaster response, precision agriculture mapping, urban planning and road network design. Its imagery will be mostly used by the Ministry of Land and Resources, the Ministry of Environmental Protection, and the Ministry of Agriculture. The satellite was launched from the Taiyuan Satellite Launch Center using a Long March-4B rocket.

On September 14, 2015, another Gaofen satellite, Gaofen-9, was launched from the Jiuquan Satellite Launch Center, using a Long March-2D. Possibly a civilian version of the Yaogan Weixing-2 (Jianbing-6) satellite, Gaofen-9 will provide sub-meter class resolution optical images for city planning, road network design, land ownership determination purposes.

A Gaofen-1 triplet was launched on March 31, 2017, by a Long March-4C from Taiyuan.

What appears to be a high-resolution optical Earth observation satellite, Gaofen-11, launched on July 31, 2018 using a Long March-4B launch vehicle from Taiyuan.

On October 4, 2019, a new satellite designated Gaofen-10 was launched using a Long March-4C vehicle from Taiyuan.

Gaofen-7 was launched on November 3, 2019, using a Long March-4B rocket from Taiyuan and Gaofen-12 was launched on November 27 using a Long March-4C also rocket from Taiyuan.

Also riding along with this mission – and also designated Hede – the HEAD satellites are built by the Shanghai Academy of Spaceflight Technology (SAST) and features a high-performance AIS-receiver being able to process 2 million Automated Identification System (AIS) short messages per 24 hours and to identify 60000 ships.

The satellites are operated by HEAD Aerospace to track ships receiving their AIS signals.

The three-axis stabilized satellites have a launch mass of 45 kg.

The Chang Zheng-2D launch vehicle is a two-stage rocket developed by the Shanghai Academy of Spaceflight Technology.

The development of CZ-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.

Long March 2D launch – photo from Chinese media.

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

Its first stage is the same as the CZ-4 Chang Zheng-4. The second stage is based on the CZ-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 2961.6kN 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, a launch mass of 39,550 kg consuming 35,550 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 CZ-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.

The first launch of the CZ-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 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 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 unmanned orbital launches by the Long March-2C, Long March-2D and Long March-4C launch vehicles.

The Launch Site – Photo via Chinese Media

Other launch zones at the launch site are used for launching the Kuaizhou and the CZ-11 Chang Zheng-11 solid propellant launch vehicles.

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).

Images released from the launch of the first Long March-11 out of Xichang appear to show that both launch complexes have integrated launch vehicles being prepared for launch. One of those rockets will be used to launch the last Beidou navigation satellite, Beidou-3GEO3, possibly on June 14. The payload of the other launch vehicle is still uncertain, either the APStar-6D communications satellite or the Fengyun-4B geosynchronous meteorological satellite.

A new remote sensing will be launched from Jiuquan on June 17. Gaofen-9 (03) will be orbited by a Long March-2D rocket.

Preparations are also on full swing at Wencheng preparing for the launch of the Tianwen-1 Mars mission using the Long March-5 (Y4) heavy launch vehicle that arrived at the new spaceport on May 24. Some sources point to a July 23 launch date on a launch window that opens on July 7 and closes at the end of August.

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