Update, 8:10pm ET (01:10am UK): Finally, SpaceX did it. During its third launch attempt from Florida's Kennedy Space Center, the rocket company successfully delivered the 6.7-ton Intelsat 35e communications satellite to geostationary transfer orbit. The mission went off nearly flawlessly. Remarkably, it was the company's third flight in 12 days, and fourth in 32 days.

Original post: After a full review of its launchpad systems and the Falcon 9 rocket, SpaceX has declared that it is ready to make a third attempt to launch a heavy communications satellite. The launch window for the Intelsat 35e mission opens at 7:38pm ET on Wednesday (00:38am UK), and it will remain so for about an hour. The launch-time weather at Kennedy Space Center is forecast to be excellent—with a 90 percent chance of favorable conditions.

SpaceX tried on Sunday and Monday to launch the satellite, but both times an unspecified technical issue with the rocket's guidance, navigation, and control system led the rocket's flight computer to stop the countdown within 10 seconds of launch time. The rocket company then stood down an attempt on July 4 so it could investigate the problem and has apparently resolved the issue. But we won't know for sure until the countdown this evening.

With a mass of 6,761kg, the Intelsat 35e communications satellite is the heaviest payload SpaceX has ever launched toward geostationary orbit, about 36,000km above the Earth's surface. For this reason, the rocket will not have enough fuel reserves to attempt a safe return to Earth—even to a drone ship in the Atlantic Ocean. This booster, therefore, will be expended.

This will be SpaceX's 10th launch of 2017, and the company has been especially busy as of late. A launch Wednesday would be the company's third flight in less than two weeks, and its fourth since June 3. By way of comparison, the most successful launches the California rocket company has had in any year, prior to this one, is eight. And it's only July.

After the Intelsat 35e mission, SpaceX will take a break for about a month. This is partly because the US Air Force needs time to upgrade some of its assets on the "Eastern Range," which tracks rocket launches along the entire US East Coast. Part of the range's purpose is to ensure the safety of shipping lanes and residents beneath the flight path of launches. As a result, no launches are planned from Kennedy Space Center or Cape Canaveral Air Force Station in Florida until August 3, when United Launch Alliance will lift a communications and data relay satellite for NASA. SpaceX's next launch is planned for no earlier than August 10, when the company will send a supply mission to the International Space Station.

The webcast below should begin about 15 minutes before the launch window opens.