Joe Palca

In space, there are no road maps. So if you happen to be heading to Jupiter, you'd better bring your own navigation tools.

One really useful tool is an instrument called a star tracker, essentially a camera with a built-in star catalog. It looks at a patch of sky, picks out stars it knows, and uses their coordinates to tell the spacecraft which way it's pointing.

After a five-year journey through the solar system, NASA's $1.1 billion Juno mission is set to begin its orbit around Jupiter on Monday. But for the probe to be captured by the giant planet's gravity and go into the desired orbit, Juno's main engine has to fire for 35 minutes.

In 1975, I was living in San Diego and needed a job. The roommate of a friend of mine was a scientist at Scripps Clinic and Research Foundation. He said a colleague of his was looking to hire a lab technician, so I applied and got the job. The scientist I worked for was some guy from a small town in Texas. His name? Jim Allison.

Since 2014, the U.S. Army has gradually been deploying the latest version of a hearing protection system that protects users from loud noises while still letting them hear the world around them.

The system is called TCAPS, or Tactical Communication and Protective System, and about 20,000 of the new TCAPS devices have been deployed in the field so far.

NASA called off today's effort to inflate an expandable module attached to the International Space Station after its first attempt fell flat.