Artemis II study finds ionospheric changes linked to GPS errors

A study by researchers at National Cheng Kung University in Taiwan says NASA’s Artemis II flight disturbed Earth’s ionosphere, producing changes in ground-based GPS measurements equivalent to possible positioning errors of several metres. The researchers say the effects were temporary and localized; their findings do not establish that vehicles or other GPS users experienced operational problems. The team analyzed data from high-precision GPS receivers at fixed stations across the United States. Those receivers recorded changes in the ionosphere’s concentration of free electrons as signals passed through the charged atmospheric layer, which begins about 30 miles (50 kilometres) above Earth. Changes in electron density can alter signal travel time and affect the position calculated by a receiver. The study identifies two broad regions of reduced electron density, each about 3,100 miles (5,000 kilometres) across. One followed the passage of the Space Launch System core stage, while the other was associated with two later burns by the rocket’s upper stage. The upper-stage burns, at about 115 miles (185 kilometres) altitude, produced the more prominent disturbance, according to...