BeiDou readies next generation of satellites

More than two years after the BeiDou Navigation Satellite System (BDS) was put into service, two new satellites in the BDS family are being prepared for operation, with the aim of testing the new generation of technologies, while improving the accuracy and reliability of the system.

At the Innovation Academy of Microsatellites of the Chinese Academy of Sciences, a team of 81 engineers and researchers with an average age of less than 31 has sent 10 BDS satellites into space so far.

Today, the development of two new satellites is nearing completion, with only the solar wings yet to be installed. The satellites are over two meters high and consist of two compartments. The upper part consists of the payloads, which allow the satellite to perform functions like positioning, navigation and timing, while the lower part is the module that ensures the satellite's stable operation.

Li Shaoqian, vice director of the satellite research institute at the academy, said that the two satellites were once backups for the BDS-3. As the BDS-3 has been operating stably, the two satellites will now be launched as test satellites to verify the new-generation BDS technology and products.

According to Li, they will verify new technologies like providing higher precision timing benchmarks and improving inter-satellite links.

They are currently at the verification stage and are expected to be launched by the end of this year or early next year. Li noted that the new technologies will greatly improve the accuracy of the BDS system's inter-satellite ranging and time synchronization.

As Li's team develops and produces the BDS satellites, Ying Jun's team is focused on the satellites' operation, making sure they have a long and robust service life.

The real-time data about satellite operations are sent back to the operation and management hall in Shanghai. The amount of data generated daily by 10 satellites is massive, and alarms often sound in the middle of the night or during holidays.

"Satellites are sometimes like kids. When the space environment is not good, they will also 'get sick' and 'feel uncomfortable'," said Ying. "Whenever this happens, we have to rush here and make them happy."

Meanwhile, some BDS satellites have entered "middle age" due to their designed lifespan. According to Ying, the design lifespan of satellites is generally 10 years, and a five-year-old satellite will encounter more problems.

"We hope that, through our efforts, they can operate for 15 years, 20 years, or even longer," said Ying.

She added that the team can now detect and handle abnormal situations earlier and faster. Data and experience accumulated over previous years will help the development of the next generation of BDS satellites.

China has negotiated many difficulties and challenges in building the BDS system.

"The only way to solve problems is through innovation," said Lin Baojun, the chief designer of the BDS-3 satellites.

"There is a tradition in the aerospace field that new technologies cannot make up more than 30 percent of a project. However, we have over 100 key technologies, almost 70 percent of which are new," said Lin.

For instance, the team optimized the design to make a satellite weighing less than a ton achieve the capacity of a 3-ton satellite.

Lin said that new technology does not mean unreliable technology. "We need to use reliable technologies, mature processes and sufficient experiments to achieve the rapid development of new technologies," Lin said.

Currently, the BDS service is within a range of 2,000 km above the Earth's surface. It is expected to address navigation issues in deep space, indoor, and underwater environments by 2035.