Spacecraft Missions How does a scientist stuck on Earth know what the weather's like in space, or which way the solar wind is blowing? Fitted with sensors and telescopes, satellites like SOHO (Solar & Heliospheric Observatory) turn space into a vast lab, where scientists study how magnetic fields and plasmas behave. These spacecraft are Earth’s early warning system, letting us know when potentially dangerous events are taking place in space, or might soon occur. FAST was launched on August 21, 1996. FAST is a satellite designed to study Earth's aurora. This highly successful spacecraft has helped scientists answer fundamental questions about the causes and makeup of the aurora. FAST's primary objective is to study the electromagnetic waves and charged particles in the aurora.