Watch the Falcon 9 launch from pad 39A

Amid a Russian spacewalk to carry out routine maintenance and inspections outside the International Space Station, two NASA astronauts and a Japanese crewmate staged a culinary first in orbit — harvesting and eating a few leaves of leafy, space-grown red romaine lettuce.

The second of three robotic resupply ships going to the International Space Station in two weeks has arrived at its launch pad in Kazakhstan for liftoff Thursday aboard a Soyuz rocket.

SpaceX engineers have narrowed the cause of last week’s unsuccessful landing of a Falcon 9 rocket booster on a barge in the Atlantic Ocean on a commanding issue with an engine throttle valve, according to Elon Musk, the company’s founder and chief executive.