Stacking of next Atlas 5 rocket begins at Cape Canaveral - Spaceflight Now

United Launch Alliance technicians positioned the first stage for the next Atlas 5 rocket on a mobile launch platform Friday at Cape Canaveral, a key step in preparations for an October mission that will debut a new solid-fueled booster design.

The Atlas 5’s bronze first stage — tail number AV-090 — was transferred from the Atlas Spaceflight Operations Center at Cape Canaveral Air Force Station to the Vertical Integration Facility just south of pad 41 early Friday.

Ground crews at the VIF raised the 107-foot (32-meter) first stage onto the Atlas 5’s mobile launch platform housed inside the vertical hangar.

In the coming days, three Northrop Grumman-made GEM 63 solid rocket motors will be mounted on the Atlas 5’s first stage.

The GEM 63 solid rocket boosters will fly for the first time on the NROL-101 mission.

Aerojet Rocketdyne’s AJ-60A motor has a flawless record since its first use on the Atlas 5’s third launch in July 2003, with 127 of the boosters flown to date.

ULA announced in 2015 the selection of Orbital ATK — now part of Northrop Grumman — to provide solid rocket boosters for future Atlas 5 launches, and for the next-generation Vulcan Centaur rocket.

The Atlas 5 rocket can fly with any number of solid rocket boosters from zero to five, while the Vulcan Centaur can launch in configurations with two, four or six boosters alongside the rocket’s two Blue Origin BE-4 main engines.

Julie Arnold, a ULA spokesperson, said the company will continue to fly the Aerojet Rocketdyne boosters on future Atlas 5 missions until the rocket is fully transitioned to the Northrop Grumman motors.