SpaceX Falcon Heavy Launch 2019 Live Stream: When to Watch Live Online as Satellites Take off From NASA Base

A SpaceX Falcon Heavy rocket is set to launch from the Kennedy Space Center in Cape Canaveral, Florida, carrying a host of scientific payloads into orbit as part of the Department of Defense's (DoD) Space Test Program-2 (STP 2) mission.

The four hour launch window opens at 11:30 p.m. EDT tonight (June 24) and proceedings from Launch Complex 39A will be streamed live on both NASA TV and SpaceX's own YouTube channel (see below) with coverage beginning on the latter around 15 minutes before the targeted lift-off time.

The STP-2 mission includes technologies developed by several organizations, including the National Oceanic and Atmospheric Administration (NOAA,) DoD research laboratories, several universities and NASA—which is sending up four payloads.

Together, scientists hope that the experiments will provide valuable data which could help to improve future spacecraft technology.

Among the most intriguing of the experiment is the "Deep Space Atomic Clock" built by NASA's Jet Propulsion Laboratory in Pasadena—a technology which has the potential to revolutionize how we navigate in space.

While still only a prototype, the clock—which is accurate to a tenth of a trillionth of a second—helps spacecraft to navigate in much the same way that GPS is used by people to find directions on Earth. The technology has the potential to be more effective than current navigation methods, and—if the demonstration is successful—could be of huge benefit to future deep space exploration missions.

Among the other payloads aboard STP-2 is a small satellite—designed by The Planetary Society—featuring a novel and non-toxic method of propulsion.
Dubbed LightSail 2, the spacecraft—which is backed by science communicator and head of the society Bill Nye—will attempt the first controlled flight in Earth's orbit powered by solar sails.

This technology uses a large sail made from a thin polyester film to harness the gentle push of photons (particles of light) in order to propel the spacecraft, in much the same way that conventional sails utilize the wind to move boats.

SpaceX CEO Elon Musk, described the STP-2 launch as the company's "most difficult launch ever," in a Twitter post. This is due to several factors, including the fact that the 24 satellites will need to be deployed at three different orbits in a mission lasting over six hours.

Furthermore, the launch will also involve four separate upper-stage engine burns, according to the company, and will also mark the first time that the Falcon Heavy's side boosters will be reused. The boosters were previously used for the April launch of the Arabsat-6A telecommunications satellite—the Falcon Heavy's first commercial mission—during which they successfully separated from the main rocket and landed safely at Cape Canaveral.

After its maiden test flight and the Arabsat-6A mission, STP-2 will be the third launch for the Falcon Heavy—the "most powerful operational rocket in the world by a factor of two," according to SpaceX.

Falcon Heavy launch
SpaceX Falcon Heavy demonstration launch on Feb. 6, 2018. NASA