Q&A with Marc Rayman, chief engineer on NASA’s Dawn mission (members only)

A commercial cargo carrier owned and operated by SpaceX pulled into port at the International Space Station on Monday, three days after launching from Cape Canaveral with a NASA Earth science instrument, a spare hand for the lab’s Canadian robotic arm, and an AI-powered helper bot for the research lab’s six-person crew.

Stratolaunch’s rocket carrier jet, the largest aircraft in the world by wing span, took off Saturday morning from the Mojave Air and Space Port in California for its first test flight.

After an extended review, NASA has opted to forgo capturing a small asteroid as an interim step on the road to sending astronauts to Mars. Instead, the agency will focus on robotically plucking a sizable boulder from the surface of an asteroid and returning it to the vicinity of the moon for analysis by spacewalking astronauts in the mid 2020s.