Fresh off Falcon Heavy, Elon Musk launches broadband test satellites Musk says he's "rebuilding the internet in space."

 -- As SpaceX's Elon Musk continues to track his red roadster's journey into deep space, he's also plotting something far more practical.

On Thursday, SpaceX on Thursday launched a pair of prototype satellites intended to form the basis for Starlink, a constellation of about 11,000 satellites that are designed to beam broadband internet down to Earth.

Today's launch - originally slated for Wednesday but put on hold because of "high altitude wind shear" - marks the first big step in Musk's plan for "rebuilding the internet in space," as he put it in 2015.

In addition to competing with typical internet providers, Starlink could deliver connectivity to rural communities without the lag they're accustomed to.

Critics - including broadband competitor OneWeb, which has already received FCC approval for its own constellation of low-Earth-orbit satellites - worry that all those SpaceX satellites whirring around would pose "danger from orbital debris," and risk collisions with other satellites already in orbit.

In a letter to the FCC, SpaceX's attorney said the company is confident Starlink is "more than capable of operating safely" and called OneWeb's concerns "self-serving and anti-competitive."

The SpaceX satellites to be delivered to low-Earth orbit this week, Microsat-2a and Microsat-2b, were carried aboard a Falcon 9 rocket that launched from Vandenberg AFB in California Thursday morning, at 6:17 a.m. local time.

They'll be monitored by receivers in California, Texas, and Washington state.

SpaceX still needs formal approval for the rest of the Starlink system, but FCC chairman Ajit Pai has already called on his colleagues to support the company's efforts to "unleash the power of satellite constellation to provide high-speed internet to rural Americans."