Jan. 11 (UPI) -- United Launch Alliance will attempt to carry out the classified NROL-47 mission on Friday. The mission will see the aerospace company launch a spy satellite into orbit using its Delta IV rocket.
The rocket launch, originally scheduled to blast-off at 4:00 p.m. ET on Thursday, was delayed until 4:55 p.m., 1:55 p.m. local time. But that launch time was canceled "due to an issue with a ground system valve," ULA said in a tweet.
The new launch time is now 4:00 p.m. on Friday, 1:00 p.m. local time.
The rocket will take-off from California's Vandenberg Air Force Base. Friday's launch will be ULA's 27th for the U.S. National Reconnaissance Office.
The NROL-47 mission was first slated to lift-off on Wednesday, a 24-hour delay was high winds forced ULA to delay the mission. Officials are hopeful the weather will cooperate this time.
"We're counting down," ULA tweeted on Thursday morning. "Latest weather briefing shows an 80% chance of favorable weather."
While details about the payload are classified, groups of amateur satellite trackers can use clues to narrow down the nature of the satellite, including its likely orbit and technology. Details such as hazard warnings issued to pilots and ships can reveal the satellite's likely orbital entry point.
According to NASA Spaceflight, NROL-47 is most likely some type of radar imaging satellite.
Thursday's mission offers ULA a chance to showcase its reliability in the wake of alleged failure of SpaceX's Zuma mission.
On Sunday, a top secret government spacecraft launched by SpaceX reportedly failed to achieve a stable orbit. The government hasn't confirmed whether the top-secret satellite did indeed fall out of orbit and reenter Earth's atmosphere.
In the aftermath of the alleged failure, SpaceX claimed its rocket performed as expected, implying the blame for the Zuma mission lay elsewhere.