ULA delays spy satellite launch to Wednesday from Florida

ORLANDO, Fla., Nov. 6 (UPI) -- United Launch Alliance plans to try again to send a Department of Defense spy satellite into orbit from Florida on Wednesday.

Liftoff on an Atlas V rocket is planned for 5:22 p.m. EST from Complex 41 at Cape Canaveral Air Force Station.

The launch company had planned a Sunday evening launch, but said Friday that the approach of a storm prompted a change.

"Due to impending weather from Tropical Depression Eta, we are rolling the Atlas V rocket carrying the NROL-101 mission ... back to secure the payload and vehicle," ULA said in an update on its website.

A problem with the rocket's propellant fuel system foiled a previous attempt the preceding Wednesday evening, and a problem with environmental controls for the satellite forced a delay the day before, ULA said.

The Defense Department's National Reconnaissance Office says little about any of its satellites, but the mission description states that the NROL 101 spacecraft will "provide intelligence data to the United States' senior policymakers" and to the nation's intelligence agencies and military.

The agency designed and built the satellite, and will operate it, according to the mission description.

ULA plans to use updated solid rocket boosters on the launch for the first time -- three GEM 63 motors built by Northrop Grumman. The strap-on boosters will add to the total thrust.

The first-stage rocket core provides 860,200 pounds of thrust at liftoff. The three side boosters provide an additional 371,550 pounds, for a total of 1.23 million pounds.

By comparison, SpaceX's Falcon 9 rocket provides more than 1.7 million pounds of thrust at liftoff, according to the company.

The new boosters are part of ULA's transition away from the Atlas V and toward a new rocket and launch system, Vulcan. The company plans its first Vulcan launch in the first half of 2021.

"The GEM 63s will be used on Atlas V launches to build flight experience in preparation for using GEM 63XLs on #VulcanCentaur's first flight," ULA posted on Twitter.