HELSINKI — China conducted a pair of launches last week to replenish its Beidou navigation system and send science and radar tech test satellites into orbit. A Long March 2C rocket lifted off at 4 a.m. Eastern May 21 from the Jiuquan Satellite Launch Center in the Gobi Desert. Aboard were the Macau Science Satellite 1A and 1B, designed to study the Earth’s magnetic field, and the Luojia-2 (01), a Ka-band synthetic aperture radar (SAR) test satellite for Wuhan University. Macau Science Satellite 1A carries payloads for measuring the Earth’s magnetic field while 1B features high-energy particle detectors and solar...