It's eerily quiet on the spaceflight front.In the past two weeks, there has been just a single orbital launch — that of a Chinese Long March 4B rocket, which lofted the Gaofen-11 05 Earth-observation satellite on July 18.

However, according to multiple sources, SpaceX was ready to launch the Falcon 9 rocket as soon as late last week. Currently, the company has a launch opportunity for no earlier than 12:14 am ET (04:14 UTC) on Wednesday for its Starlink 10-4 mission.

Falcon 9 is the world's most popular launching vehicle and has only failed twice in 366 launches across 14 years, according to SpaceX figures. It also launches cargo missions to the ISS, satellites for NASA and the national military, and numerous other missions.

SpaceX is seeking a rapid return to Falcon 9 launches following a rare failure of its workhorse rocket during a satellite launch last week.

Additionally, SpaceX sends a portion of vital resupply missions to the ISS via its cargo Dragon spacecraft. Cargo Dragon also uses the Falcon 9 rocket. The last such docking, SpaceX's 30th, took place on March 4 with food, supplies and experiments for the Expedition 70/71 crew.

The engine failure blamed for stranding 20 Starlink satellites in a low, non-survivable orbit was caused by a liquid oxygen leak.