LIVE: SpaceX takes a second try for a potentially historic rocket landing

On Sunday SpaceX will make a second attempt at a historic rocket landing on a floating platform in the ocean.

A 22-story-tall Falcon 9 rocket will lift off out of Cape Canaveral Air Force Station in Florida a couple of minutes after sunset, at 6:10 ET. The weather for take off looks clear as of 5pm.

And within a half hour or so after take-off, the rocket will return from space and attempt to guide its way, using GPS tracking, onto a droneship in the Atlantic.

Five years ago, a landing attempt like this was unheard of. But SpaceX is changing things up and paving the way for a new era of reusable rockets. The company, founded by billionaire entrepreneur Elon Musk, has gone to great lengths to build the foundations for a future of cheap space travel. The key to that future is reusable rockets that can carry cargo and astronauts into space multiple times instead of only once.

So far, SpaceX has never recovered a rocket for reuse. But if everything goes according to plan this Sunday and the rocket lands softly, it would be a game changer.

NASA TV will be streaming the launch live starting at 3:30 p.m. ET on Sunday. The live stream is provided below.

Broadcast live streaming video on Ustream

 If the launch is aborted, SpaceX has prepared a backup launch opportunity for 6:07 p.m. on Monday. And with 17 potential rocket launches scheduled for 2015, there is plenty of opportunity to get it right even if this latest attempt doesn't work.

The re-entry and landing of the rocket will be even more difficult this time around, because this mission is to send a satellite into deep space, Musk tweeted:

The rocket had trouble on the last attempt, because it ran out of hydraulic fluid, sending it careening out of control on its way onto the drone ship:

Technology for the future

The landing attempt isn't the only exciting thing about Sunday's launch. For this launch, the rocket will also ferry an important instrument into space: the Deep Space Climate Observatory (DSCOVR).

DSCOVR, shown to the right, is the latest instrument that the National Oceanic and Atmospheric Administration will use to monitor solar winds. The sun emits gusts of high-energy particles in the form of solar wind, and when those gusts occasionally reach Earth's magnetic field it can disrupt the planet's power grids, telecommunications, aviation, and GPS.

Having a satellite like this is "the first line of defense ... for us to be able to take the appropriate action to protect our system from any impacts that could happen," said David Velazquez, the executive vice president for Pepco Holdings Inc. - a holding company for the Potomac Electric Power Company - in a NOAA video.

After the rocket detaches from DSCOVR in space, the climate observatory will begin a 110-day long journey to its final orbit while the rocket will head back toward Earth.

There's a special point in space, called Lagrangian Point 1, where a spacecraft can orbit so that it will always remain between the Earth and the Sun.

"The L1 position will provide DSCOVR with a point of 'early warning' when a surge of particles and magnetic field from the sun will hit Earth," NASA said in a statement. The observatory will sound the alarm 30 to 45 minutes ahead of time.