Exactly How SLS’s First Launch Impacted Launch Complex 39B
Just last month the Space Launch System lifted off and became the most powerful operational rocket in the world. While the overall mission was a major success with Orion splashing down almost a month later, not every aspect was perfect. Being that SLS is such a powerful launch vehicle, the mobile launcher and surrounding pad infrastructure sustained quite a bit of damage.
However, after NASA looked further into the details, they found that the various systems performed much better than expected. A lot of which has to do with the significant amount of upgrades that have been made in the last few years in preparation for Artemis missions. With this in mind, the agency is now hard at work trying to prepare for Artemis II with the first humans on top of SLS.
While the rocket itself is obviously an important part of these missions, the ground infrastructure plays just as important role with many different unique and complex systems to try and contain and help facilitate a rocket launch. Here I will go more in-depth into what NASA found after the first SLS launch, how they are preparing for Artemis II, what to expect in the future, and more.
Artemis I Impact
Launch Pad 39B is a historic launch site that was first designed for the Saturn V launch vehicle, which at the time was the United States’ most powerful rocket. It then was used to launch NASA’s crewed spaceflight missions from the late 1960s up until the start of the Space Launch System. Following the successful liftoff of the world’s most powerful rocket from NASA’s Kennedy Space Center in Florida, teams carefully assessed the mobile launcher and infrastructure at Launch Pad 39B. Engineers determined the overall mobile launcher and pad systems all performed as designed during launch and were structurally sound.
The ground systems, umbilical, software, and ignition over pressure and sound suppression system from the water deluge system, which sprays water to dampen the acoustic shock and protect the deck of the mobile launcher from the flames of the engines, all supported the launch as expected throughout countdown and as the Space Launch System rocket imparted 8.8 million pounds of thrust onto the structure while leaving Earth. “The exploration ground systems exceeded our expectation for its overall performance,” Artemis mission manager, Mike Sarafin said during a Nov. 21 news briefing following Orion’s closest lunar flyby. “We did have a little bit of damage on the mobile launcher, but it will be ready to support Artemis II and we had accounted for that previously in our pre-plan and our budget for the time between Artemis I and II.”
The assessment, which began the day of launch, Wednesday, Nov. 16, and concluded Friday, Nov. 18, enabled teams to inspect areas on the mobile launcher and identify specific damage and debris around the pad. Engineers identified minor damage to umbilicals and the crew access arm on the mobile launcher. Damage to the pneumatic lines associated with gaseous nitrogen and gaseous helium caused the oxygen sensors on the pad to show there were low oxygen readings due to leaks, which teams have since isolated. The most significant issue is the damage to the elevators, which required the team to use the stairs for inspections on the 355-foot-tall tower structure, which has 662 steps, and extended the time required for the inspection. The agency pointed out that the elevators will remain out of service for several months to complete repairs.
In addition, debris assessments around the pad found the solid rocket booster’s throat plug material which is purposefully expelled at liftoff and commonly found at the pad post launch. Other debris found at the pad included pieces of the caulk-like material from Orion, though teams are unclear if that was detached during launch or during Hurricane Nicole. Overall, the mobile launcher and pad post launch inspections yielded findings that are consistent with expectations and similar to those of space shuttle launches. Now at a parking location at Kennedy, it will undergo emergency egress modifications and testing to prepare for the Artemis II crewed mission which is already making progress.
Pad Upgrades
Now that we know some of the damage that was found and the overall results on the pad after Artemis I, we can take a closer look at the long list of upgrades made over the past few years in preparation for returning humans to the Moon. Launch Pad 39B at NASA’s Kennedy Space Center in Florida underwent a metamorphosis from top to bottom to support the agency’s Space Launch System (SLS) rocket with the Orion spacecraft atop for their first integrated uncrewed flight test. While modifications to the surface of the pad and work in the flame trench are visible, upgrades to other systems may not be as obvious, but are vital to ensuring safe and successful launches into deep space and NASA’s Journey to Mars.
“We have been steadily working on a series of projects to modernize or refurbish every part of the pad,” said Regina Spellman, launch pad senior project manager in the Ground Systems Development and Operations (GSDO) Program. “Upon completion of this group of projects, we are entering the home stretch in our preparation for the first launch.” These upgrades include a new communication system; new heating, ventilation and cooling system; replacement of water system piping in the pad perimeter; and installing new ignition overpressure/sound suppression bypass valves at the valve complex.
One of the most interesting and important upgrades had to do with the flame trench. In June 2015, NASA awarded a contract to J.P. Donovan Construction of Rockledge, Florida, to upgrade the flame trench and provide a new flame deflector. This system is critical to safely containing the plume exhaust from the massive rocket during launch. Construction workers began by removing old adhesive material and preparing the walls for brick installation on the north side of the trench. “It’s very exciting to see this project making such great progress. The flame trench and flame deflector are the last large pieces of the puzzle required at the pad prior to integrating testing with the mobile launcher and before launch,” said Regina Spellman, GSDO launch pad senior project manager.
The north side of the flame trench is about 571 feet long, 58 feet wide, and 42 feet high. The new flame deflector will divert the rocket’s exhaust, pressure, and heat to the north. To determine where the most pressure and heat will occur during launch, a team of engineers from Kennedy and NASA’s Ames Research Center in Moffett Field, California, used computational fluid dynamics to locate the areas of significant temperature and pressure. In these areas of concern, adhesive anchors were drilled into the walls at intervals to hold the metal plates that will reinforce the brick system before the mortar and bricks were added.
Construction workers then prepared the north side of the flame trench to withstand temperatures of up to 2000 degrees Fahrenheit at launch of the rocket’s engines and solid rocket boosters. Approximately 100,000 heat-resistant bricks, in three different sizes, were secured to the walls using bonding mortar in combination with the adhesive anchors. “The contractor is performing quality checks as the work progresses,” said Lori Jones, an engineer and project manager for Construction of Facilities for the pad flame trench and deflector. Because all of the rocket’s flame and energy at liftoff will be diverted to the north side of the flame trench, the south side of the flame trench will not be covered in brick, but instead, will be repaired and remain a concrete surface.
The new flame deflector will be positioned about six feet south of the old flame deflector’s position. The north side of the deflector will be protected by a NASA standard coating. The south side of the deflector will not be slanted and will have no lining. The new design will provide easier access for inspection, maintenance and repair. The two side flame deflectors, repurposed from space shuttle launches, were refurbished and reinstalled at pad level on either side of the flame trench to help reduce damage to the pad and SLS rocket. In order to accommodate the new configuration, an access door between the west catacomb and the main deflector was moved to a new location. A new opening was cut into the east side of the flame trench wall to relocate the ignition over pressure/sound suppression system’s water pipes that will feed the deflector’s crest spray system.
At the time, the flame trench modifications were scheduled to be completed by March 2017, however, this took a bit longer. Additional work was also done to reinforce the catacomb below the pad surface so it can handle the load of the SLS rocket. A previously completed project included removal of all of the crawler track panels on the pad’s surface, repair of the surface beneath the panels and the catacomb roof below, and reinstallation of existing panels or, depending on their condition, installation of some new track panels.
Conclusion
It takes a lot more than just a launch vehicle in order to successfully lift off from Earth. The infrastructure necessary only becomes more complicated when the rocket gets even more powerful. An increasingly difficult task for one of the most powerful rockets in the world. We will have to wait and see how it progresses and the impact it has on the space industry.