China launches two satellites to monitor Earth's weakening magnetic field

May 22, 2023

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China launched two satellites designed to investigate and monitor Earth's magnetic field changes at 4 pm local time on Sunday, May 21, at the Jiuquan launch site in the Gobi Desert.

The mission called Macau Science 1 lifted a pair of satellites weighing 500kg (1,100lbs) each atop a Long March 2C rocket. It is the first Chinese space mission operated as part of a partnership with scientists in Macau, according to a report by the South China Morning Post.

The two satellites are set to operate in two slightly different orbits: one will fly 400km (250 miles) above Earth, while the other will operate at an altitude of 500km (310 miles).

China's space agency, the China National Space Administration (CNSA), stated that the two satellites will make some of the most accurate measurements of Earth's magnetic field to date. They hope the mission will help shed new light on the formation of Earth's magnetic field and how it changes over time.

Earth's magnetic field is crucial to our existence. Without its protection, cosmic rays would batter us, and Earth wouldn't be able to sustain a livable atmosphere.

While we know that Earth's magnetism originates from the liquid metal in its molten outer core, we don't quite understand why the strength of the magnetism has decreased slightly since records began — it has weakened by about nine percent over the past 200 years, according to NASA. The decrease has been most prominent between South America and Southwest Africa in the South Atlantic.

While this decrease isn't an immediate cause for alarm, some scientists have hypothesized that Mars may have once had an atmosphere that was swept away due to the cooling of its core and the subsequent decline of its magnetic field.

Still, the Macau Science 1 mission is tasked with making sense of the so-called South Atlantic Anomaly. It will do so by probing 3,000 km into Earth's interior. Both satellites have a series of impressive instruments ranging from high-precision magnetometers to detectors that monitor the surrounding space environment.

The new satellites follow in the footsteps of Europe's three-satellite Swarm mission and the Chinese-Italian Zhangheng 1 satellite mission, which also collects data on Earth's geomagnetic field.

The Macau Science 1 team will now perform in-orbit scientific instrument tests aboard the satellite over the next six to 12 months. If all goes to plan, the satellites are expected to operate and collect data on Earth's magnetic field for at least five years.