NASA is resuming work on a series of tests to bring the Space Launch System (SLS) rocket core stage to life for the first time, allowing engineers to evaluate the new complex stage that will launch the Artemis I lunar mission. Learn more about this exciting moment in space exploration history from Boeing SLS Engineer Tony Castilleja in a live broadcast noon Oct. 2 in Space Center Theater.
About the speaker
Tony Castilleja received his Bachelors of Science and Master’s in Mechanical Engineering and has worked at Boeing for more than a decade starting on the Space Shuttle Program in the Mission Evaluation Room at Mission Control, built Astronaut Trainers for the Boeing Starliner to International Space Station, and works on the Space Launch System, the NASA Rocket to the Moon and Mars.
What is a Green Run?
This Green Run is the step-by-step testing and analysis of the new SLS rocket core stage that will send astronauts to the Moon.
In January, engineers began activating the stage’s components one by one over several months through a series of initial tests and functional checks designed to identify any issues. Those tests and checks collectively called Green Run will culminate in a test fire replicating the stage’s first flight.
Green Run tests minimize risk to the core stage and ensure the stage satisfies design objectives and validates design models.
How many tests are there?
- Modal Test: The first test in the Green Run series, a modal test was conducted in January. This test used shakers to impart dynamic forces on the suspended stage to identify primary bending modes of the stage. Information from the modal test will help engineers verify vehicle models needed for the operation of the rocket’s guidance, navigation and control systems.
- Avionics: The rocket’s avionics, which are distributed throughout the stage, will be turned on and checkout out. This includes not only flight computers and electronics that control the rocket but also those that collect flight data and monitor the overall health of the core stage.
- Fail-Safes: Engineers will check out all the safety systems that shut down operations during testing. To do this, they will simulate potential issues.
- Propulsion: This will be the first test of each of the main propulsion system components that connect to the engines. Command and control operations will be verified, and the core stage will be checked for leaks in fluid or gas.
- Thrust Vector Controls: Engineers will ensure that the thrust vector control system can move the four engines and check all the related hydraulic systems.
- Countdown: This test simulates the launch countdown, including step-by-step fueling procedures. Core stage avionics are powered on, and propellant loading and pressurization are simulated. The test team will exercise and validate the countdown timeline and sequence of events.
- “Wet” Dress Rehearsal: Engineers will demonstrate loading, controlling and draining more than 700,000 gallons of cryogenic propellants into the two test stand run tanks and then returning the stage to a safe condition.
- Hot Fire: The core stage's four RS-25 engines will operated for up to eight minutes, generating 1.6 million pounds of thrust, the amount of thrust the engines produce at sea level on the launch pad at liftoff.
What happens after the tests?
After the hot fire test, engineers will refurbish the core stage and configure it for its journey to Kennedy for launch preparations. The next time the RS-25 engines fire, the SLS will launch in an epic debut of Artemis I ̶̶ the first in a series of increasingly complex missions that will enable human exploration to the Moon and Mars.
Note: This event is included in general admission.