Q&A with Guglielmo Aglietti, RemoveDebris principal investigator (members only)

Hours after calling off a launch of a different rocket from a nearby launch pad, SpaceX’s launch team loaded a Falcon 9 rocket with propellant Saturday and fired its nine main engines on pad 40 at Cape Canaveral Air Force Station, setting the stage for a liftoff with a South Korean military satellite as soon as Tuesday amid a busy stretch of missions for the California-based rocket company.

Flying its most complex mission to date, a Japanese H-2A rocket fired off a launch pad and roared into space from southern Japan on Tuesday, heading for an on-target deployment of the Telstar 12 Vantage communications satellite four-and-a-half hours later.

SpaceX is set to launch two prototype probes Wednesday to begin testing spacecraft and antenna technology the company hopes will eventually power a network of thousands of satellites blanketing planet Earth with broadband Internet coverage.