Artemis I SSL ICPS Lift and Mate

Teams with NASA’s Exploration Ground Systems and contractor Jacobs integrate the interim cryogenic propulsion stage (ICPS) for NASA’s Space Launch System (SLS) rocket with the launch vehicle stage adapter (LVSA) atop the massive SLS core stage in the agency’s Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida on July 5, 2021. The ICPS is a liquid oxygen and liquid hydrogen-based system that will fire its RL 10 engine to give the Orion spacecraft the big in-space push needed to fly tens of thousands of miles beyond the Moon. The next component to be stacked on top of ICPS will be the Orion stage adapter, which will connect the ICPS with the spacecraft. Through Artemis, NASA will send the first woman and the first person of color to the lunar surface, as well as establish a sustainable presence on and around the Moon. As the first in an increasingly complex set of missions, Artemis I will test SLS and Orion as an integrated system prior to crewed flights to the Moon.

As crews at NASA’s Kennedy Space Center assemble the Moon rocket for the Artemis I mission, teams have installed the flight software that will help steer, fly, track, and guide the spacecraft during launch and ascent to space. Engineers loaded the flight software onto the Space Launch System rocket Aug. 6 after powering up the core stage that contains the flight computers for the first time since stacking began.

With the software installed, the engineers who developed the flight software at Marshall Space Flight Center are supporting final checkouts and completing tests to certify the software for the mission.

“NASA’s Space Launch System is on the path to the pad, and the SLS flight computer application software is complete and ready to perform the mission,” David Beaman, SLS systems engineering and integration manager, said. “The mission certification and performance certification tests are the next step for the rocket’s software on the path to launch and flight ahead of Artemis I.”

The software is loaded on three flight computers, along with the avionics systems inside the SLS rocket’s core stage. On the day of launch, the SLS’s twin solid rocket boosters and four RS-25 engines fire together to produce more than 8.8 million pounds of thrust to send NASA’s Orion spacecraft to the Moon. The software and avionics operate with the rocket’s three flight computers to harness the power of the rocket through ascent and communicate with avionics systems inside the engines and the boosters. That same software is monitored in real time by NASA’s Exploration Ground Systems team at the agency’s launch complex at Kennedy and SLS Program engineers at the SLS Engineering Support Center at Marshall. 

Once the rocket and Orion are fully stacked and assembled on the mobile launcher, they will undergo several additional tests and checkouts leading up to launch. The software is designed to be tested and certified for each launch window so that ascent performance parameters can be updated right up until launch to enhance mission success.

“It is important to test and certify the SLS flight software for each launch opportunity to account for day of launch weather and other factors,” Dan Mitchell, lead SLS integrated avionics and software engineer, said. “Those tests also ensure that all the software elements and systems on the rocket, Orion, and the ground work together seamlessly for prelaunch checks and preparations, liftoff, and ascent.”

NASA conducts integrated end-to-end testing for the software, hardware, avionics, and integrated systems needed to fly Artemis missions. Each hardware element is tested before delivery to Kennedy. In addition, testing in the agency’s sophisticated software development laboratories uses actual SLS, Orion, and Exploration Ground Systems flight hardware and software, as well as emulators – versions of the software that each team employs to test how their code works with the integrated system – to support both system-level interface testing and integrated mission testing to ensure software and avionics systems work together.

Earlier this year, the flight software and avionics systems completed a series of checkouts and tests as part of the comprehensive, eight-part SLS core stage Green Run test series at NASA’s Stennis Space Center. Key tests and checkouts included powering on the stage, simulating the launch countdown, and operating the flight computers and avionics systems during the eight-minute hot fire test March 18.  

During Green Run, the core stage flight computers, software, and avionics systems performed as expected as test teams monitored and operated the flight software just like they would in a launch environment for the first time. Those data findings were then used to inform the mission certification testing for the Artemis I flight software.

Extensive testing was also completed on the flight computer application software for Artemis I in Marshall’s System Integration Lab. Inside, software engineers create real-time launch simulations to further test the flight software under normal and unplanned mission scenarios.

“The flight software test campaign for the Artemis I mission involves more than 300,000 different mission scenarios to satisfy all flight software requirements,” Shaun Phillips, SLS flight software project team lead based at Marshall, said. “Each of these scenarios are focused on evaluating different interfaces and situations the vehicle may face during launch and flight.”

NASA thoroughly tests and evaluates all software and hardware for every phase of the Artemis I mission to ensure that it meets safety requirements and is fully qualified for human spaceflight. With Artemis, NASA will land the first woman and the first person of color on the Moon and establish a long-term presence while preparing for human missions to Mars. SLS and NASA’s Orion spacecraft, along with the commercial human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission.

Editor’s note: Corinne Edmiston, a Media Fusion employee, supports Marshall’s Office of Strategic Analysis & Communications.

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