SLS Rolled Out To The Pad, NASA Announces More Powerful SLS Variant, & More
For months now the Space Launch System has been going to and from the VAB as NASA continues to try and launch this rocket. Marked as one of the first significant steps in returning humans to the surface of the Moon, this first launch apart of Artemis 1 is very important. Thankfully, after additional work inside the Vehicle Assembly building, it looks as if we are just over a week away from launch.
Specifically, just yesterday on the 4th, SLS officially arrived back on pad 39B after sitting with the VAB since late September. Currently on track for its next launch attempt just 9 days away on the 14th. In addition to progress toward this first launch, NASA also released new information about enhancing the SLS rocket for future missions.
This included work on the SLS Block 1B variant, expected to be capable of lifting 40% more mass than the current Block I SLS configuration that will soon launch the uncrewed Artemis I flight test. Here I will go more in-depth into the recent rollout back onto the pad, why this more powerful configuration is so important, what to expect in the coming weeks, and more.
Rollout & Launch
In the last two days, NASA worked to both prepare and roll SLS back to the launch pad once again. Late at night on the 3rd, the Space Launch System rocket and Orion spacecraft for the Artemis I flight test began rolling to launch pad 39B at NASA’s Kennedy Space Center in Florida ahead of launch. At about 11:17 p.m. EDT the crawler-transporter began the approximately 4-mile journey from the Vehicle Assembly Building (VAB) to the launch pad. Once outside the VAB high-bay doors, the Moon rocket made a planned pause allowing the team to reposition the crew access arm on the mobile launcher before continuing to the launch pad. Overall the journey took about 9 hours throughout the night. Yesterday NASA tweeted saying, “Thanks @NASAGroundSys! We have arrived! Around 8:30 a.m. EDT on Nov. 4, the Space Launch System rocket and @NASA_Orion spacecraft for the #Artemis I mission arrived at launch pad 39B at @NASAKennedy in Florida for the upcoming Nov. 14. launch attempt.”
In the over month long period the rocket was inside the VAB, NASA completed a few necessary tasks. For one, minor repairs identified through detailed inspections were completed. Testing of the reaction control system on the twin solid rocket boosters, as well as the installation of the flight batteries, was completed and those components were deemed ready for flight. Engineers also replaced the batteries on the interim cryogenic propulsion stage (ICPS), which was powered up for a series of tests to ensure the stage is functioning properly. Teams successfully completed final confidence checks for the ICPS, launch vehicle stage adapter, and the core stage forward skirt. Teams also recharged, replaced, and reinstalled several of the radiation instruments and the crew seat accelerometer inside Orion ahead of the crew module closure for roll. Now that SLS is on the launch pad, technicians will refresh the specimens for the space biology payload. The flight termination system batteries were also reset giving the agency around a month for more launch opportunities.
The November launch period stretches from November 12th till the 27th with a few exceptions along the way. If NASA is unable to launch SLS within this period, the next opportunity begins December 9th. These launch periods are quite interesting and highlight the different factors that need to be considered when launching to the Moon. Specifically, these mission availability dates consider daylight conditions when Orion splashes back down on Earth, they must support a skip entry trajectory with the Moon, ensure Orion is not in darkness for more than 90 minutes during its journey, and also account for the Moon’s position. If everything goes according to plan, in just 9 days we will watch SLS lift off for the first time.
More Powerful Configuration
Now that we know more about SLS’s recent journey back to the launch pad and some of the work that has been done, we can take a closer look at NASA’s recent announcement regarding a more powerful SLS variant. Yesterday NASA tweeted saying, “On Nov. 3, @NASA reached a milestone toward enhancing the SLS rocket for future missions when managers convened for the critical design review of the Block IB evolved configuration of the rocket that will be used beginning with #Artemis IV”
In this case, beginning with Artemis IV, the SLS rocket will fly using the evolved Block 1B configuration with a more powerful Exploration Upper Stage (EUS) that includes larger fuel tanks and four RL10 engines, and a new stage adapter and payload adapter to send the crewed Orion spacecraft and large cargos to the Moon on a single mission. This Block 1B configuration will be capable of launching more than 80,000 pounds of payload to the Moon, includes new flight software capabilities, allows for more launch date opportunities, and enhances crew safety. It will be capable of lifting 40% more mass than the current Block I SLS configuration that will soon launch the uncrewed Artemis I flight test, as well as the Artemis II and III missions. The Block I configuration uses an interim cryogenic propulsion stage with one RL10 engine to provide in-space propulsion to send Orion to the Moon.
In reality, NASA has been planning on a long variant line of SLS for quite a while now. This list includes SLS Block 1 Crew, Block 1B Crew, Block 1B Cargo, and Block 2 Cargo Evolution. In total there are 6 variants that each have a specific purpose and goal revolving around the future of humans on the Moon.
Focusing back on yesterday’s announcement, early production work on an EUS structural test article is already in progress at NASA’s Michoud Assembly Facility in New Orleans, and teams recently delivered the interstage simulator to NASA’s Stennis Space Center near Bay St. Louis, Mississippi, for future testing. As teams at Michoud build SLS core stages for future Artemis missions, they are also testing the weld parameters on the recently manufactured EUS hydrogen tank barrel weld confidence article. These tests will allow engineers to construct the EUS structural test article that will be used to qualify the stage for flight. Manufacturing the upper stage is a collaborative effort between NASA and Boeing, the lead contractor for EUS and the SLS core stage. It’s important to point out that this variant is not expected to be used for a long time. As of right now, Artemis IV is set to lift off no earlier than 2025, as the agency needs to complete the first 3 missions before. Starting with Artemis I, scheduled on the 14th of this month.
Artemis I is the first integrated test of NASA’s deep space exploration systems: the Orion spacecraft, Space Launch System (SLS) rocket and the ground systems at the agency’s Kennedy Space Center in Florida. The first in a series of increasingly complex missions, Artemis I is an uncrewed flight test that will provide a foundation for human deep space exploration and demonstrate our commitment and capability to return humans to the Moon and extend beyond. During this flight, Orion will launch atop one of the most powerful rockets in the world and fly farther than any spacecraft built for humans has ever flown. Over the course of the mission, it will travel 280,000 miles (450,000 kilometers) from Earth and 40,000 miles (64,000 kilometers) beyond the far side of the Moon. Orion will stay in space longer than any human spacecraft has without docking to a space station and return home faster and hotter than ever before.
This first Artemis mission is intended to demonstrate the performance of both Orion and the SLS rocket and test NASA’s capabilities to orbit the Moon and return to Earth. With Artemis I, NASA sets the stage for human exploration into deep space, where astronauts will build and begin testing the systems near the Moon needed for lunar surface missions and exploration to other destinations farther from Earth, including Mars. With Artemis, NASA will collaborate with industry and international partners to establish long-term exploration for the first time.
In this mission, after about four to six weeks and a total distance traveled exceeding 1.3 million miles, the mission will end with a test of Orion’s capability to return safely to the Earth as the spacecraft makes a precision landing within eyesight of the recovery ship off the coast of Baja, California. Following splashdown, Orion will remain powered for a period of time as divers from the U.S. Navy and operations teams from NASA’s Exploration Ground Systems approach in small boats from the waiting recovery ship. The divers will briefly inspect the spacecraft for hazards and hook up tending and tow lines, and then engineers will tow the capsule into the well-deck of the recovery ship to bring the spacecraft home. If successful, the next step will be a crewed mission to the Moon apart of Artemis II.
Conclusion
NASA has been trying to launch SLS for multiple months now. Throughout this time period, a lot of issues and various complications have come in the way of the first Artemis mission. Thankfully, the rocket just arrived at the pad and will have another attempt in just over a week. We will have to wait and see how it progresses and the impact it has on the space industry.