China launches Brazilian remote sensing satellite

by Chris Bergin

China were back in launch action this morning, with the lift-off of a Brazilian observation and remote sensing satellite. The launch was on behalf of the CBERS Program, via their CZ-4B Chang Zheng-4B (Long March-4B) rocket.

Lift-off took place at 03:26 UTC, launching from the Taiyuan Satellite Launch Center. This marks China’s eighth launch of the year.




The satellite belongs to the first generation of CBERS satellites and is almost identical to the CBERS-1 (October 14th, 1999) and CBERS-2 (October 21st, 2003) satellites.

The new CBERS-2B includes upgrades for improved performance. The IRMSS imager – that was launched on the first two satellites of the CBERS series – was replaced by a high-resolution panchromatic camera, CPAR, with a resolution of 2.7 meters per pixel. The spacecraft also has a new Global Positioning System and a star tracker.

The integration and testing of the satellite took place on the LIT (Laboratorio de Integracao e Testes – Test and Integration Laboratory) from the INPE (Instituto Nacional de Pesquisas Espaciais) – National Institute of Space Research, located in Sao Jose dos Campos, Brazil.

The CBERS-2B orbit will be sun synchronized, at an altitude of 778 km. Utilizing this orbit, the CBERS-2B will always cross the equator at the same local time and lightning conditions that will allow for the comparison of images taken on different days.

Using the CCD and IRMSS, the CBERS-2B will be able to cover the entire planet over a 26 day period, using a field of 113 km wide and 120 km wide – while the WFI the satellite will be able to complete global coverage in just five days, with its field of 890 km wide.

The satellite is composed of two modules: a Cargo Module and a Service Module. The Cargo Module contains the optical systems (CCD, CPAR and WFI) and the RSBCDA (Repetidor para o Sistema Brasileiro de Coleta de Dados Ambientais) – a Brazilian System for the Collection of Environmental Data.

The Service Module contains the power sources, control systems, telecommunication systems and other elements necessary for the operation of the vehicle.

The electrical power required for the operation of the satellite will be gained via the 6.3 meter long and 2.6 meter wide solar panel, which will deploy after entering orbit. The panel will be continuously oriented to the Sun using an automatic control system. The satellite is equipped with two Nickel Cadmium batteries.

The attitude control of the CBERS-2B is a key element for mission success and is unique to this series of spacecraft. CBERS-2B is equipped with a GPS system and star tracker system that will control the attitude control systems.

The satellite will use hydrazine thrusters to control attitude and maintain to do orbital correction manoeuvres. The internal environment of the satellite will be kept by an active and passive thermal control system.

CBERS-2B has a total mass of 1450 kg, and its dimensions are 1.8 x 2.0 x 2.2 meters. The satellite has three axis stabilization – and should operate in orbit for the next two years.

It was a long road to launch, starting in January 2007, when the satellite was placed through environmental testing, following by a month of electromagnetic interference tests. Following this, the satellite was put to its paces with mass measuring tests, leak tests on the propulsion system, vibration tests and acoustic tests. There were 30 Chinese technicians present at the LIT during the integration and tests phases.

Last April, the satellite was shipped to China’s CAST (Chinese Academy of Space Technology), which also runs the CBERS program. Together with 30 tons of equipment that was shipped to China, a group of 12 Brazilian technicians were on hand to prepare CBERS-2B for launch.

The Chang Zheng-4B launch vehicle used to launch CBERS-2B arrived at the Tayiuan Satellite Launch Center in the last week of August. On the morning of September 6, the satellite was transported from the Technical Center to the Launch Platform. The satellite took almost one hour to get from the Technical Center to the Launch Platform, separated by 7 km.

The satellite was carried on a special adapted vehicle, capable of offering the environmental conditions necessary to keep the spacecraft in a healthy state. After the fuelling of the satellite, it was assembled on the third stage adapter on September 5. After arriving to the Launch Platform, the third stage adapter was hoisted and integrated to the third stage of the launcher.

The final integration tests on the CBERS-2B satellite were completed on September 12 without issue. These tests verified the connections between the satellite and the third stage of the launch vehicle – and also between the satellite and the launch center.

The launch simulation of CBERS-2B took place September 14, with the satellite was placed in its launch configuration, two hours before lift-off.

The CZ-4B is a three stage launch vehicle, capable of launching a 4595 kg payload to a low Earth orbit, or 1419 kg to a GTO. This launcher derived from the CZ-4A, with a modernized third stage and payload fairing.


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