The hours-long disposition process is currently scheduled to begin at 9 p.m. EDT on Tuesday, August 16 (01:00 UTC on Wednesday, August 17), weather permitting – which will result in a sunrise arrival at the pad. The disposition is the last major milestone before launch, which will differ from more recent missions in that the required azimuth — or flight path of the rocket — will change continuously through each day’s launch window. Launch to the Moon Launching into a rendezvous orbit with a satellite or low-Earth orbit station can be simplified by the need to launch directly into the plane – and therefore the same orbital inclination – of the target’s orbit. For example, when launching to the International Space Station from Florida, the azimuth followed by the rocket is 44.98°. This does not change based on when the lift occurs within the daily window. However, the same is not true when trying to launch into an interceptor orbit with the Moon. As stated by Artemis 1 Ascent/Entry Flight Director Judd Frieling at NASASpaceflight during Artemis Day events at Mission Control at Johnson Space Center, the Moon’s orbital motion combined with its ever-changing relative inclination to the launch site complicates the required launch azimuth for SLS.
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On each launch day, the SLS azimuth must fly incrementally, second by second, across the window to match the Moon’s motion relative to Earth for the interlunar injection burn (TLI). According to NASA, for SLS and Artemis 1, the azimuth at the window opening in all three launch attempts on August 29, September 2, and September 5 is 62°, resulting in an inclined orbit of 38°. At the end of each window, the azimuth would be 108° on a 32° inclination orbit. But before the SLS can prepare to enter the course on launch day, it must first reach the pad. Released for release The launch of Artemis 1 will mark the first time since May 31, 2011, that a vehicle will emerge from the Vehicle Assembly Building (VAB) at Kennedy Space Center for launch operations. SLS and Orion on LC-39B during preparations for WDR (Credit: Julia Bergeron for NSF/L2) As it has done twice already for wetsuit rehearsal campaigns, the SLS rocket for Artemis 1 will make the trip aboard LC-39B atop Carrier-Tracker 2, one of two NASA-owned carrier-trackers and the only modified to carry the full stack the Artemis/SLS vehicle on the pad. The upgrades were necessary due to the age of the crawler and the increased mass of the SLS vehicle with the combined Mobile Launcher (ML). The combined SLS/ML weight is about 15 million pounds (6.8 million kg) and is significantly heavier than the previous Space Shuttle record holder at 12 million pounds (5.4 million kg). Upgrades included 18 million pounds (8.1 million kg) of handling capacity, 50% more payload than originally planned, as well as a new 1,500-kilowatt electric generator, parking and service brakes, redesigned and upgraded roller bearings, and more modifications for the Artemis program. Like the crawlers, their custom-built road, the crawler road, also underwent upgrades between Shuttle and SLS. Beginning in 2013, the crawler’s foundations were repaired with new limestone to restore it to its original state and prepare for the Block 1B SLS, currently scheduled for the end of the decade, which will be heavier than the Block 1 SLS which was used for Artemis 1. The 15 million pound SLS and ML on LC-39B during the Wet Dress Rehearsal. (Credit: Nathan Barker for NSF) In addition, 30,000 tons of new Alabama River rock was added to return the crawler road to its optimal depth. For Launch Complex 39B, which was used for the Apollo, Skylab, Apollo-Soyuz, Space Shuttle, and Ares IX missions, the pad was slowly modified, beginning in the final years of the Shuttle program, to a pure pad configuration with three , Towers of 600-foot (183 m) lightning rods connected by catenary cables. The clean pad is without the Shuttle-era fixed and rotating service structures that served the Shuttle stack. The sound suppression system, flame trench, wiring and other systems were also upgraded during the transition to the SLS. Work on Pad 39B also included a new 1.25 million gallon liquid hydrogen tank, although it is not yet complete and will not be used for Artemis 1. Pad 39B’s clean pad configuration was designed to be able to handle different types of rockets as part of a multi-user spaceport emphasis. To date, only Northrop Grumman has expressed interest in a pad share for the now-cancelled OmegA missile. Artemis 1 Artemis 1 is scheduled to spend 13 days at Pad 39B after launch on August 16. During this time, the ML will be connected to the hydraulics that service the rocket with liquid oxygen, liquid hydrogen, helium and liquid nitrogen. Crawler-Transporter-2 (CT-2) during disposition testing. (Credit: NASA) Other round systems required for the launch will also be activated while the teams conduct system checks on SLS and Orion. If all goes well, the stage will be set for the 60th overall launch — and the second lunar flight since Apollo 10 — from Pad 39B. The countdown for Artemis 1 is currently scheduled to begin with the Call To Stations at 9:53 AM. EDT (13:53 UTC) on August 27. The feed will begin early on the morning of August 29 for a two-hour launch window that opens at 8:33 AM EDT (12:33 UTC). In total, Artemis 1 has 25 days to launch after completing the flight termination system (FTS) test on the launch vehicle on August 12. In the event that Artemis 1 is unable to launch on August 29, launch windows of September 2 and 5 are available. The two-hour launch window on September 2 begins at 12:48 p.m. EDT (16:48 UTC) while the September 5 window lasts 90 minutes, starting at 5:12 p.m. EDT (21:12 UTC). If Artemis 1 cannot make either of the launch windows, Crawler Transporter 2 would return to Pad 39B to return the stack to the VAB for FTS replacement and any other work the vehicle or ML may need before the next available launch window , likely October 17 to 31. Wide-angle photo showing the massive 525-foot-tall vehicle assembly building. Crawler-transporter 2 is now in place under @NASA_SLS and @NASA_Orion and ready for launch tomorrow at Launch Pad 39B. pic.twitter.com/fCDGS0wouf — NASA’s Exploration Ground Systems (@NASAGroundSys) August 15, 2022 Together, the first two SLS/Orion Artemis missions will pave the way for the first human lunar landing since 1972 on Artemis 3, which is currently scheduled for no earlier than late 2025. Artemis 3 will use SLS and Orion to transport astronauts to lunar orbit, where a SpaceX Starship lander procured under the HLS contract will ferry them to and from the surface near the Moon’s south pole. Just under 50 years after humanity last left the Moon in December 1972, Artemis 1 is ready to begin our return journey. This time to stay. (Main photo: SLS basks in the morning sun on LC-39B. Credit: Stephen Marr for NSF)
