Q&A with Heino Falcke, principal investigator of the Netherlands-China Low-Frequency Explorer (members only)

SpaceX’s launch team loaded super-chilled liquid propellants into a two-stage Falcon 9 rocket Wednesday and fired the booster’s nine first stage engines at Cape Canaveral, marching toward liftoff Monday with a NASA observatory built to find planets around other stars in our galactic neighborhood.

Europe’s LISA Pathfinder mission — a fundamental physics lab launched last year to a point a million miles from Earth — has demonstrated the mind-boggling technology required for a future space-based observatory to listen for faint, low-frequency vibrations emitted by invisible objects in the most distant pockets of the universe, scientists said this week.

Soaring more than 200 miles above Earth, a Chinese spacecraft with two astronauts on-board closed in for docking with the Tiangong 2 space lab just before 1930 GMT (3:30 p.m. EDT).