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China’s largest rocket apparently wasn’t big enough to launch the country’s newest spy satellite, so engineers gave the rocket an upgrade.

The Long March 5 launcher flew with a payload fairing some 20 feet (6.2 meters) taller than its usual nose cone when it took off on Friday with a Chinese military spy satellite. This made the Long March 5, with a height of some 200 feet, the tallest rocket China has ever flown.

Adding to the intrigue, the Chinese government claimed the spacecraft aboard the Long March 5 rocket, named Yaogan-41, is a high-altitude optical remote sensing satellite. These types of surveillance satellites usually fly much closer to Earth to obtain the sharpest images possible of an adversary’s military forces and strategically important sites.

This could mean a few things. First, assuming China’s official description is accurate, the satellite could be heading for a perch in geosynchronous orbit, a position that would afford any Earth-facing sensors continuous views of a third of the world’s surface. In this orbit, the spacecraft would circle Earth once every 24 hours, synchronizing its movement with the planet’s rotation.

Because this mission launched on China’s most powerful rocket, with the longer payload fairing added on, the Yaogan-41 spacecraft is presumably quite big. The US military’s space tracking network found the Yaogan-41 satellite in an elliptical, or oval-shaped, soon after Friday’s launch. Yaogan-41’s trajectory takes it between an altitude of about 121 miles (195 kilometers) and 22,254 miles (35,815 kilometers), according to publicly available tracking data.

This is a standard orbit for spacecraft heading into geosynchronous orbit. It’s likely in the coming weeks that the Yaogan-41 satellite will maneuver into this more circular orbit, where it would maintain an altitude of 22,236 miles (35,786 kilometers) and perhaps nudge itself into an orbit closer to the equator.

Staring down from space

In an official statement, China’s state-run Xinhua news agency claimed Yaogan-41 will be used for civilian purposes, such as land surveys and agricultural monitoring. In reality, China uses the Yaogan name as a blanket identifier for most of its military satellites.

US military officials will closely watch to see where Yaogan-41 ends up. If it settles into geosynchronous orbit over the Indian or Pacific Oceans, as analysts expect, Yaogan-41 would have a constant view of China, Taiwan, and neighboring countries.

From such a high altitude, Yaogan-41’s optical imager won’t have the sharp vision of a satellite closer to Earth. But it’s easy to imagine the benefits of all-day coverage, even at lower resolution, without China’s military needing to wait hours for a follow-up pass over a potential target from another satellite in low-Earth orbit.

In August, China launched a synthetic aperture radar surveillance satellite into a geosynchronous-type orbit using a medium-lift Long March 7 rocket. This spacecraft can achieve 20-meter (66-foot) resolution at Earth’s surface with its radar instrument, which is capable of day-and-night all-weather imaging.

Optical payloads, like the one on Yaogan-41, are restricted to daytime observations over cloud-free regions. China launched a smaller optical remote sensing satellite into geosynchronous orbit in 2015, ostensibly for civilian purposes.

Although Chinese officials did not disclose the exact capabilities of Yaogan-41, it would almost certainly have the sensitivity to continually track US Navy ships and allied vessels across a wide swath of the Indo-Pacific. Aside from its use of the larger payload fairing, the Long March 5 rocket used to launch Yaogan-41 can haul approximately 31,000 pounds (14 metric tons) of payload mass into the orbit it reached on Friday’s launch.

This suggests China could have equipped Yaogan-41 with a large telescope to stare down from space. Notably, China acknowledged Yaogan-41’s purpose as an optical imaging satellite. China’s government doesn’t always do that. Perhaps this is a signal to US officials.