LULU GARCIA-NAVARRO, HOST:
2020 could be a banner year for the U.S. space program. If all goes well, two commercial companies may be able to send astronauts into space. This country hasn't been able to do that since the shuttle program ended in 2011. Also next year, a new six-wheeled rover is supposed to head off to Mars. And hundreds of small satellites are scheduled to go into orbit. And that will provide global Internet coverage. Here to talk about the year ahead in space is NPR science correspondent Joe Palca. Hey, Joe.
JOE PALCA, BYLINE: Hey, Lulu.