China is supersizing its rocket industry – and it’s coming for Starlink

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The Long March 8 is a low-cost, non-reusable rocket that can house more than 20 Starlink-sized communication satellites. China intends to use the medium-sized launch vehicle, which has seen two successful test launches, to send more than 1,000 satellites into space every year, comparable to the current pace of SpaceX.

A giant satellite constellation is driving China’s space industry into a new age Song Zhengyu

But the new rocket is also designed to put satellites in a higher orbit than the Starlink satellites. The more advantageous altitude would allow Chinese satellites to monitor or even suppress their American rivals.

The race to “build a giant satellite constellation is driving China’s space industry into a new age”, said Song Zhengyu, a senior rocket scientist with the China Academy of Launch Vehicle Technology (CALT), who is leading the Long March 8 team, in a paper published in the Chinese Journal of Astronautics last month.

Production with a pulse

In a bid to catch up with SpaceX’s Starlink programme, China plans to launch nearly 13,000 satellites, in addition to the more than 4,000 satellites it currently has in orbit.

The project – code-named “GW” – is specifically aimed at suppressing Starlink’s global services in the event of war, according to some PLA scientists.

But China’s current line-up of rockets is not up to the task, according to Song and his colleagues. Existing Long March rockets are either too small or too big, they said.

The Long March 8 is designed to fill the gap, with unprecedented efficiency.

A Long March 8 rocket carrying 22 satellites blasts off from a Wenchang launch site in 2022. Photo Xinhua

The Chinese scientists also developed a new method to guide and control the rocket during flight, which involves alternating powered flight and gliding to optimise the rocket’s trajectory.

Specifically, during the first part of the second stage of flight, the rocket glides along a suborbital path to a specific target. Then, during the second part of the second stage, it switches to powered flight to reach its final target orbit.

The method allows for more precise control over the rocket’s trajectory and can help it adapt to deviations from its intended path. It is difficult to achieve because it requires precise timing and coordination between different stages of the rocket’s flight.

Gliding in space is difficult since there is no air resistance to help control the rocket’s movement. The new method is a key advancement in rocket technology that could improve the accuracy and efficiency of space missions, according to Song’s team.

To reduce costs even more, the Long March 8 no longer requires a triple redundant inertial measurement unit (IMU) configuration. Instead, it uses a simplified dual IMU configuration. This requires new technology to improve flight reliability and intelligence, and uses alternative methods to address potential failures.

Gaining altitude

Long’s team said that the Long March 8 rocket is optimised to send satellites to the sun-synchronous orbit (SSO) at an altitude of 700km (435 miles), higher than most Starlink satellites, which operate at about 550km.

At present, the SSO is used mainly by Earth observation satellites. It is called “sun-synchronous” because the satellite passes over any given point on Earth at the same local time each day, which makes it easier to take consistent measurements of things like temperature, vegetation growth and ocean currents.

SSO has advantages and disadvantages compared to the LEO used by most Starlink satellites. One advantage is that it allows for more consistent and accurate data collection, since the satellite passes over the same area at the same time of day.

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