On Thursday, a few hours before SpaceX was due to launch a new version of its Falcon 9 rocket, company CEO Elon Musk admitted he was nervous. SpaceX had significantly revamped the nine-engine booster that had powered its astonishing rise to the top of the aerospace industry. Now came the final test.

"The reason that it's so hard to make an orbital rocket work is that your passing grade is 100 percent, and you can't fully and properly test an orbital rocket until it launches," Musk said. He paused a moment and then added, "Man, anyway, I'm stressed."

As it turned out, the Block 5 version of the Falcon 9 rocket did not undergo its orbital test on Thursday, as the ground control systems at Kennedy Space Center stopped the rocket's countdown with just 58 seconds to go. Because there were only about 30 minutes left in the two-hour launch window to send the Bangabandhu Satellite-1 to geostationary transfer orbit, the company ultimately had to scrub and turn around to try for a second launch attempt Friday.

Musk reiterated Thursday that this will be the final "substantial" upgrade to the Falcon 9 rocket, optimizing the booster for reuse. The company hopes to be able to fly each Block 5 first stage 10 times before significant refurbishment is required. The tenth flight of one of these rockets could come as early as the end of next year, Musk said.

Ten flights of an individual booster would be hugely significant, as SpaceX has thus far only reused each of its Falcon 9 rockets a single time. Additionally, the company hopes to reduce the turnaround time between launches of a Falcon 9 booster, now several months, to a matter of weeks or even days. (Musk said Thursday that as early as next year, the company will attempt to refly the same Falcon 9 booster within 24 hours).

The approximately two-hour launch window opens Friday at 4:14pm ET (20:14 UTC). Weather conditions are slightly less favorable than they were on Thursday, but the official launch forecast still calls for a 70 percent chance of "go" conditions on Friday. The webcast below should begin 15 to 20 minutes before the launch window opens.