Q&A with Mark Sirangelo, leader of Sierra Nevada Space Systems

A SpaceX Dragon supply ship packed with nearly three tons of experiments, crew provisions and supplies will remain on the ground until at least Friday morning to allow more time for NASA flight controllers to troubleshoot a problem with an electrical distribution unit on the International Space Station.

Sierra Nevada Corp. has booked at least six launches on United Launch Alliance’s new Vulcan Centaur rocket to carry Dream Chaser supply ships into orbit on cargo runs to the International Space Station beginning in 2021, becoming the first confirmed customer for ULA’s next-generation launcher.

The last of Japan’s first series of HTV supply ships departed the International Space Station on Tuesday with several tons of trash, old batteries, and unneeded equipment, heading for a destructive re-entry before the debut of an upgraded cargo freighter design.