NASA’s Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test on November 16, 2022, from Launch Complex 39B at NASA’s Kennedy Space Center in Florida. NASA’s Artemis I mission is the first integrated flight test of the agency’s deep space exploration systems: the Orion spacecraft, Space Launch System (SLS) rocket, and ground systems. SLS and Orion launched at 1:47 a.m. EST, from Launch Pad 39B at the Kennedy Space Center. Credit: NASA/Joel Kowsky
NASA continues to evaluate data and learn more about the Space Launch System (SLS) rocket’s debut performance during the agency’s November 16, 2022, Artemis I launch. Following an initial data assessment and review that determined the SLS rocket met or exceeded all performance expectations, SLS engineers are now taking a closer look at the Moon rocket’s performance to prepare for the first crewed Artemis missions.
Building off the assessment conducted shortly after launch, the preliminary post-flight data indicates that all SLS systems performed exceptionally and that the designs are ready to support a crewed flight on Artemis II. The post-flight analysis team will continue reviewing data and conducting final reports.
The core stage of NASA’s Space Launch System (SLS) rocket has more than 1,000 sensors and 45 miles of cabling. The SLS core stage’s base heat shield is roughly 1.3 inches thick and was specially designed to protect the 212-foot-tall stage and its two liquid propellant tanks from launch pad temperatures greater than 3,200 degrees Fahrenheit. Data indicates the structure was not affected by temperatures that can turn sand to glass. Credit: NASA/Chris Coleman and Kevin Dav
“NASA’s Space Launch System rocket has laid the foundation for the Artemis Generation and the future of spaceflight in deep space,” said John Honeycutt, SLS Program manager. “The correlation between actual flight performance and predicted performance for Artemis I was excellent. There is engineering and an art to successfully building and launching a rocket, and the analysis on the SLS rocket’s inaugural flight puts NASA and its partners in a good position to power missions for Artemis II and beyond.”
Ahead of launch, teams established benchmarks for the rocket’s performance through a series of pre-flight simulations and test campaigns. As the rocket launched and ascended to space, it experienced dynamic phases, like extreme forces and temperatures, that influenced its operations. The Artemis I flight test was the only way to gather real data on how the rocket performed during events like booster separation.
Four RS-25 engines and two five-segment solid rocket boosters provide more than 8.8 million pounds of thrust for SLS during liftoff and flight. Thanks in part to the development of a new RS-25 engine controller that checks engine health 50 times per second, engineers were able to collect more than 100 measurements on pressures, temperatures, flows, speeds, and vibrations on the four RS-25 engines that helped power Artemis I. Credit: NASA/Joel Kowsky
Engineers in the SLS Engineering and Support Center at NASA’s Marshall Space Flight Center in Huntsville, Alabama, collected more than four terabytes of data and on-board imagery from SLS during pre-launch and launch phases. In addition, a total of roughly 31 terabytes of imagery data alone was collected from ground cameras, cameras on the rocket, and aerial cameras that were focused on SLS. By comparison the Library of Congress’ printed material is roughly 20 terabytes.
“The data we got back from Artemis I is critical in building confidence in this rocket to send humanity back to the Moon,” said John Blevins, SLS chief engineer. “The SLS team will use what we learn from this flight test to improve future flights of the rocket, and we are already taking what we’ve learned about operations and assembly and applying it to streamline future missions.”
Experience the Artemis I launch from the engine ignition to Orion’s separation on its journey to the Moon. Credit: NASA
Cameras and sensors also allowed teams to monitor how the rocket performed during its in-space maneuvers. Seeing launch from the SLS rocket’s “view” (see video above) involved strategically positioning cameras, sensors, and other measurement tools all along the rocket, the mobile launcher, and the launch pad.
“The numerous views of the Artemis I rocket, including the solid rocket booster separation and interim cryogenic propulsion stage (ICPS) separation, provided imagery data that helped us assess how SLS performed from liftoff through the ascent and separation events,” said Beth St. Peter, SLS imagery integration lead.
NASA’s Space Launch System (SLS) rocket delivers propulsion in stages with the interim cryogenic propulsion stage (ICPS) providing the in-space “push” the Orion spacecraft needs to get to the Moon. During Artemis I, the ICPS performed two successful burns to send Orion to the Moon, including the longest RL10 engine burn in the design’s 50-year-plus history and hundreds of missions. Credit: NASA
Engineers also monitored the extreme temperatures and sounds the rocket experienced just after liftoff. SLS post-flight data have shown the RS-25 engines’ thrust and mixture ratio control valves were within 0.5% of predicted values. The mixture ratio is the ratio of fuel to oxidizer that determines the temperature and thrust coming from the engines throughout their eight minutes of flight time. Other key engine internal pressures and temperatures were within 2% of pre-flight predicted values.
In flight, the SLS core stage successfully executed all of its functions and inserted the ICPS and Orion spacecraft into an initial Earth orbit of 972.1 miles by 16 miles. The insert was just 2.9 miles shy of the perfect bullseye target of 975 miles by 16 miles and well within acceptable parameters. Following a near-perfect trans-lunar injection burn, the ICPS and Orion spacecraft successfully separated – allowing Orion to complete a 25.5-day mission.
As part of the Artemis program, NASA aims to achieve multiple milestones, including landing the first woman and person of color on the Moon’s surface. This will create a foundation for long-term lunar presence and serve as a crucial stepping stone for astronauts on their way to Mars.
“initial Earth orbit of 972.1 miles by 16 miles” I don’t understand how this can be an earth orbit. 16 miles is low stratosphere – not good orbit territory. Is this just the low point on an orbit that was never completed? i.e. the TLI occurred before the low point would have occurred.