Interstage adapter installed on Space Launch System

The Launch Vehicle Stage Adapter is lowered on top of the Space Launch System core stage inside High Bay 3 of the Vehicle Assembly Building. Credit: NASA/Frank Michaux

NASA has stacked the next piece of the agency’s first Space Launch System moon rocket at the Kennedy Space Center, adding an adapter structure to connect the launch vehicle’s core stage and upper stage, which is scheduled to be installed next week.

Ground crews inside the Vehicle Assembly Building at the Kennedy Space Center connected the Launch Vehicle Stage Adapter, or LVSA, on top of the SLS core stage Tuesday inside High Bay 3 after lifting the structure across the VAB by crane.

The LVSA is the structural interface between the SLS core stage with the rocket’s Interim Cryogenic Propulsion Stage, or upper stage. The element was built at NASA’s Marshall Space Flight Center in Huntsville, Alabama, under the management of prime contractor Teledyne Brown Engineering.

The cone-shaped adapter has a height of about 30 feet, or 9 meters, and tapers from the top of the 27.6-foot-diameter (8.4-meter) core stage to the base of the 16.8-foot-diameter (5.1-meter) upper stage. The LVSA will also help protect the upper stage’s RL10 engine during the early minutes of the SLS launch, before the RL10 fires to send an Orion capsule on a trajectory toward the moon.

Before the stacking of the LVSA this week, ground teams mounted the 212-foot-tall (65-meter) Boeing-built SLS core stage between the rocket’s twin solid-fueled boosters. That milestone was completed June 13.

Technicians with NASA’s ground systems team, along with contractor Jacobs, are overseeing stacking of the first Space Launch System rocket.

The first pieces of the SLS to be stacked on the rocket’s mobile launch platform were the two five-segment solid rocket boosters. The boosters, supplied by Northrop Grumman, stand about 177 feet (54 meters) tall.

NASA still hopes to launch the first SLS test flight as soon as November. The mission, named Artemis 1, will send an unpiloted Orion crew capsule to orbit the moon and return to Earth.

But officials don’t expect the stacking and checkouts of the first Space Launch System rocket to go perfectly. Any technical issues or weather-related delays during this year’s hurricane season would force a delay in the Artemis 1 launch until early 2022.

The Launch Vehicle Stage Adapter is lowered on top of the Space Launch System core stage inside High Bay 3 of the Vehicle Assembly Building. Credit: NASA/Frank Michaux

The upper stage for the first Space Launch System mission was built by United Launch Alliance. The stage is based on the second stage of ULA’s Delta 4-Heavy rocket.

ULA delivered the upper stage to the Vehicle Assembly Building earlier this week. Stacking of that piece of the rocket is scheduled some time next week.

Once the upper stage is mounted on top of the SLS in High Bay 3, teams will install the Orion Stage Adapter, a ring that connects the rocket to the Orion spacecraft. During the Artemis 1 launch, 13 CubeSats will ride to space on the Orion adapter ring for deployment on science and technology demonstration missions.

Next will come a mass simulator for the Orion spacecraft.

That will set the stage for a test to verify the propellant lines, fluid connections, and other umbilicals running between the mobile launch platform’s tower and the rocket can safely release and retract as they will at liftoff.

Then teams will move into structural resonance testing, or modal testing, of the fully-stacked launch vehicle in July and August. Once that is complete, teams will move the real Orion spacecraft — which will already be integrated with its launch abort system — to the VAB for attachment to the top of the Space Launch System.

That milestone is currently scheduled for some time in August.

The entire Space Launch System rocket will stand 322 feet (98 meters) tall. Its two solid rocket boosters and four hydrogen-fueled RS-25 main engines, all based on leftover hardware from the space shuttle program, will generate about 8.8 million pounds of thrust at liftoff, more than any U.S. rocket flown to date.

Assuming no significant delays, NASA plans to roll the rocket and its mobile launch platform to launch pad 39B in late September or early October for a practice countdown, when engineers will load cryogenic propellants into the rocket during a dress rehearsal for launch day.

The SLS and Orion spacecraft will return to the Vehicle Assembly Building for final closeouts, inspections, and ordnance connections.

The next time the rocket rolls out to pad 39B will be around six day before launch.

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