After nearly a month, United Launch Alliance will try once again early Sunday to launch a secret spy satellite from Cape Canaveral.
An attempt to launch the satellite on ULA's Delta IV Heavy rocket last month was aborted in the final seconds of the countdown -- right as the engines were firing.
The company says an issue with a regulator on the launch pad was to blame for the nearly month-long delay and it has replaced all three regulators out of an abundance of caution.
An attempt to launch Saturday was delayed due to "an issue with the swing arm retraction system."
ULA is launching a spy satellite for the National Reconnaissance Office. Not much is known about the payload. The NRO operates a fleet of spy satellites, providing data to U.S. intelligence agencies.
Sunday's launch window opens at 12:10 a.m. ET and the weather forecast is about 60 percent favorable for launch.
EDITORS NOTE: This story was updated to reflect a new launch time from ULA.
