{"id":89557,"date":"2026-09-11T17:29:28","date_gmt":"2026-09-11T09:29:28","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/?p=89557"},"modified":"2026-09-11T17:59:25","modified_gmt":"2026-09-11T09:59:25","slug":"both-bound-for-the-moon-why-are-nasas-sls-and-spacexs-starship-so-different","status":"publish","type":"post","link":"https:\/\/starpath.global\/blog\/both-bound-for-the-moon-why-are-nasas-sls-and-spacexs-starship-so-different\/","title":{"rendered":"Both Bound for the Moon: Why Are NASA\u2019s SLS and SpaceX\u2019s Starship So Different?"},"content":{"rendered":"<p>On one side is the orange-and-white SLS. On the other is Starship, resembling a stainless-steel tower. Both are part of the United States\u2019 architecture for returning humans to the Moon, yet they have almost nothing in common\u2014from their appearance and engines to how they are intended to operate.<\/p>\n<p><strong>Their respective roles:<\/strong> SLS Block 1 and Starship are not simply two different approaches to building the \u201csame rocket.\u201d Led by NASA, SLS currently forms part of a crewed deep-space transportation chain centered on the Orion spacecraft. Developed by SpaceX, Starship was designed from the outset around reusability, high-frequency launches and in-space refueling. Within the Artemis program, Starship HLS serves as a commercially developed crewed lunar lander\u2014a role distinct from that of Orion.[1]<\/p>\n<h2>1. Before Comparing the Rockets, Look at Where They Fit into the Mission<\/h2>\n<p>Most rocket comparisons begin with payload capacity, vehicle height and engine count. But the first difference between SLS and Starship lies in their mission boundaries.<\/p>\n<p>SLS is the launch element of NASA\u2019s Artemis crewed deep-space exploration system. Together with Orion, the launch site and ground systems, it forms a tightly controlled mission chain: the rocket sends Orion and its astronauts into space, while Orion handles deep-space travel, rendezvous and docking, and the return to Earth.[1][2]<\/p>\n<p>Starship, by contrast, is a large transportation system that SpaceX is continuing to iterate. The general-purpose Starship system is intended to make both its first stage and upper stage reusable. Starship HLS is a commercially developed lunar lander modified specifically for transporting astronauts between lunar orbit and the Moon\u2019s surface.[1][6]<\/p>\n<p>Under NASA\u2019s updated 2026 schedule, Artemis III will first demonstrate rendezvous and docking between Orion and a commercial lunar lander test article in low Earth orbit in 2027. The target for a crewed lunar landing has shifted to Artemis IV in 2028. This revised timeline makes the division of responsibilities even clearer: SLS\/Orion and the commercial HLS are two interconnected segments of the mission architecture.[1]<\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Two Mission Chains for the Same Lunar Goal<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">SLS and Orion handle crewed deep-space transportation, while commercial human landing systems cover the lunar segment.<\/div>\n<div style=\"background-color: #ffffff; padding: 18px 16px;\">\n<div style=\"color: #27718d; font-size: 18px; font-weight: bold; text-align: left; margin-bottom: 14px;\">2027 Artemis III: Near-Earth-Orbit Docking Demonstration<\/div>\n<table style=\"width: 100%; border-collapse: separate; border-spacing: 0; table-layout: fixed; text-align: center; background-color: #ffffff; margin: 0;\">\n<tbody>\n<tr>\n<td style=\"width: 20%; padding: 18px 8px; font-size: 15px; font-weight: 600; line-height: 1.5; color: #173f59; background-color: #edf4f7; border: 1px solid #cbd5e1; border-radius: 8px;\">SLS<br \/>\nLaunch<\/td>\n<td style=\"width: 6%; padding: 8px 2px; font-size: 26px; font-weight: bold; color: #d88b2f;\">\u2192<\/td>\n<td style=\"width: 20%; padding: 18px 8px; font-size: 15px; font-weight: 600; line-height: 1.5; color: #173f59; background-color: #edf4f7; border: 1px solid #cbd5e1; border-radius: 8px;\">Orion<br \/>\nCrew Transport<\/td>\n<td style=\"width: 6%; padding: 8px 2px; font-size: 26px; font-weight: bold; color: #d88b2f;\">\u2192<\/td>\n<td style=\"width: 20%; padding: 18px 8px; font-size: 15px; font-weight: 600; line-height: 1.5; color: #173f59; background-color: #edf4f7; border: 1px solid #cbd5e1; border-radius: 8px;\">Commercial Lunar Lander Test Article<\/td>\n<td style=\"width: 6%; padding: 8px 2px; font-size: 26px; font-weight: bold; color: #d88b2f;\">\u2192<\/td>\n<td style=\"width: 22%; padding: 18px 8px; font-size: 15px; font-weight: 600; line-height: 1.5; color: #173f59; background-color: #edf4f7; border: 1px solid #cbd5e1; border-radius: 8px;\">Rendezvous and Docking Validation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div style=\"background-color: #ffffff; padding: 18px 16px 20px;\">\n<div style=\"color: #c7812b; font-size: 18px; font-weight: bold; text-align: left; margin-bottom: 14px;\">2028 Artemis IV Goal: Crewed Lunar Landing<\/div>\n<div style=\"background-color: #123d63; border-radius: 10px; padding: 18px 20px 8px;\">\n<div style=\"color: #ffffff; font-size: 18px; font-weight: bold; text-align: left; margin-bottom: 12px;\">Division of Responsibilities for Lunar Missions<\/div>\n<table style=\"width: 100%; border-collapse: collapse; text-align: left; background-color: transparent; margin: 0;\">\n<tbody>\n<tr>\n<td style=\"width: 31%; padding: 12px 8px 12px 0; font-size: 15px; font-weight: 600; color: #64c3d4; border-bottom: 1px solid rgba(255,255,255,0.2);\">Earth \u2192 Moon<\/td>\n<td style=\"width: 23%; padding: 12px 8px; font-size: 15px; font-weight: 600; color: #ffffff; border-bottom: 1px solid rgba(255,255,255,0.2);\">SLS + Orion<\/td>\n<td style=\"width: 46%; padding: 12px 0 12px 8px; font-size: 15px; line-height: 1.5; color: #e2e8f0; border-bottom: 1px solid rgba(255,255,255,0.2);\">Crewed launch, deep-space transit and return to Earth<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 12px 8px 12px 0; font-size: 15px; font-weight: 600; color: #64c3d4;\">Lunar Orbit \u2192 Surface<\/td>\n<td style=\"padding: 12px 8px; font-size: 15px; font-weight: 600; color: #ffffff;\">Commercial HLS<\/td>\n<td style=\"padding: 12px 0 12px 8px; font-size: 15px; line-height: 1.5; color: #e2e8f0;\">Astronaut transfer, lunar descent and ascent<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p><!-- Source --><\/p>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\"><em>Table 1. Division of responsibilities between SLS\/Orion and the commercial HLS in Artemis missions. Source: Table created by the author based on publicly available NASA information.<\/em><\/div>\n<h2>2. The Shape of SLS Is Defined by Its Liquid-Hydrogen Core Stage and Solid Rocket Boosters<\/h2>\n<p>SLS Block 1 consists of the Orion spacecraft at the top, the Interim Cryogenic Propulsion Stage, or ICPS, a massive core stage and two five-segment solid rocket boosters. The core stage is powered by four RS-25 engines burning liquid hydrogen and liquid oxygen. The ICPS also uses liquid hydrogen and liquid oxygen, with propulsion provided by a single RL10 engine.[2][4]<\/p>\n<p>Liquid hydrogen delivers excellent performance by mass, but its density is extremely low, requiring very large propellant tanks. With a boiling point of approximately 20 K, it also places demanding requirements on insulation, plumbing, valves and ground-based fueling systems. The SLS core stage\u2019s enormous, elongated shape is largely a consequence of these physical properties.<\/p>\n<p>The rocket also needs extremely high thrust at liftoff. Its two five-segment solid rocket boosters provide most of the initial thrust during approximately the first two minutes of flight before separating. The high thrust of the solid boosters and the high efficiency of the core stage\u2019s hydrogen-fueled engines perform complementary roles within the same launch vehicle.[3]<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-89566\" src=\"\/wp-content\/uploads\/2026\/09\/SLS-and-Orion-lift-off-on-the-Artemis-I-mission-on-November-16-2022.webp\" alt=\"SLS and Orion lift off on the Artemis I mission on November 16, 2022. Source: NASA\/Joel Kowsky, image ID NHQ202211160027.\" width=\"1220\" height=\"684\" srcset=\"\/blog\/wp-content\/uploads\/2026\/09\/SLS-and-Orion-lift-off-on-the-Artemis-I-mission-on-November-16-2022.webp 1220w, \/blog\/wp-content\/uploads\/2026\/09\/SLS-and-Orion-lift-off-on-the-Artemis-I-mission-on-November-16-2022-300x168.webp 300w, \/blog\/wp-content\/uploads\/2026\/09\/SLS-and-Orion-lift-off-on-the-Artemis-I-mission-on-November-16-2022-1024x574.webp 1024w, \/blog\/wp-content\/uploads\/2026\/09\/SLS-and-Orion-lift-off-on-the-Artemis-I-mission-on-November-16-2022-768x431.webp 768w\" sizes=\"(max-width: 1220px) 100vw, 1220px\" \/><\/p>\n<p><em>SLS and Orion lift off on the Artemis I mission on November 16, 2022. Source: NASA\/Joel Kowsky, image ID NHQ202211160027.<\/em><\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Why SLS Block 1 Is Orange and White<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">A central liquid-hydrogen\/liquid-oxygen core stage with two five-segment solid rocket boosters<\/div>\n<table style=\"width: 100%; border-collapse: collapse; text-align: left; background-color: #ffffff; margin: 0; border-spacing: 0;\">\n<thead>\n<tr style=\"background-color: #3b74bf; color: #ffffff;\">\n<th style=\"width: 28%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">Component<\/th>\n<th style=\"width: 30%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">Configuration<\/th>\n<th style=\"width: 42%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-bottom: 1px solid #0b3c85;\">Function<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Orion Spacecraft<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Crew spacecraft<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Crewed deep-space transportation and return<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Interim Cryogenic Propulsion Stage (ICPS)<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">One RL10 engine; liquid hydrogen and liquid oxygen<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Provides in-space propulsion after core-stage separation<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Core Stage<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Four RS-25 engines; liquid hydrogen and liquid oxygen<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Serves as the rocket\u2019s main propulsion stage<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1;\">Two Five-Segment Solid Rocket Boosters<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1;\">Mounted on either side of the core stage<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50;\">Provide high thrust during liftoff<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div style=\"background-color: #f1f5f9; padding: 14px 16px; font-size: 14px; color: #475569; border-top: 1px solid #cbd5e1; line-height: 1.6; text-align: left;\"><span style=\"display: block; color: #173f59; font-size: 16px; font-weight: 600; margin-bottom: 6px;\">Its Appearance Reflects Its Thermal Design<\/span>The core-stage tanks are primarily made of 2219 aluminum alloy. The orange exterior is spray-on foam insulation that helps keep the propellants at cryogenic temperatures while protecting the vehicle against moisture and the thermal environment of flight. The orange color is neither decorative nor the natural color of the tanks.<\/div>\n<\/div>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\"><em>Table 2. The configuration of SLS Block 1 and the factors behind its appearance. Source: Table created by the author based on publicly available NASA information.<\/em><\/div>\n<h2>3. Starship Looks Like a Stainless-Steel Tower Because the Entire Transport System Is Intended to Fly Many Times<\/h2>\n<p>The Starship system consists of the Super Heavy first stage and the Starship upper stage. Under the current official baseline configuration, Super Heavy is powered by 33 Raptor engines using superchilled liquid oxygen and liquid methane. SpaceX designed the system with first-stage return, launch-tower catch, upper-stage recovery and subsequent reflights all taken into account.[6]<\/p>\n<p>That objective fundamentally changes the vehicle\u2019s mass budget. An expendable rocket mainly needs to complete its ascent mission. A reusable rocket must also retain propellant for its return, carry control surfaces and a thermal protection system, and withstand repeated loads during both ascent and recovery. All of these requirements consume mass and volume that could otherwise be allocated to payload.<\/p>\n<p>The lunar version of Starship introduces another critical step: the in-space transfer of cryogenic propellant. To complete its lunar transfer, descent and ascent, HLS must accumulate propellant in low Earth orbit through multiple launches of tanker Starships. Starship HLS is therefore not merely a spacecraft. It is part of a broader system encompassing launch sites, tanker vehicles, orbital propellant storage, rendezvous and docking, and cryogenic fluid management.[6][8]<\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Starship Builds Reuse and Refueling into Its Architecture<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">First-stage return, upper-stage return and in-orbit cryogenic propellant transfer must each be validated separately.<\/div>\n<table style=\"width: 100%; border-collapse: collapse; text-align: left; background-color: #ffffff; margin: 0; border-spacing: 0;\">\n<thead>\n<tr style=\"background-color: #3b74bf; color: #ffffff;\">\n<th style=\"width: 10%; padding: 12px 10px; font-size: 15px; font-weight: 600; text-align: center; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">Step<\/th>\n<th style=\"width: 27%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">Capability<\/th>\n<th style=\"width: 63%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-bottom: 1px solid #0b3c85;\">Configuration or Validation Requirement<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">1<\/td>\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Launch<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Liquid oxygen and liquid methane propulsion with multiple engines operating in parallel<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">2<\/td>\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">First-Stage Return<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Recovery by the launch tower, a capability already demonstrated in flight testing<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">3<\/td>\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Upper-Stage Reuse<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Requires the upper stage to return, be recovered and fly again as the same vehicle<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1;\">4<\/td>\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1;\">In-Orbit Refueling<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50;\">Rendezvous and docking between two vehicles, followed by cryogenic propellant transfer<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; border-top: 1px solid #cbd5e1; line-height: 1.6; text-align: left;\"><span style=\"font-weight: 600; color: #173f59;\">Vehicle configuration:<\/span> A Starship upper stage mounted atop a Super Heavy first-stage booster powered by 33 Raptor engines.<\/div>\n<\/div>\n<p><!-- Source --><\/p>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\">Table 3: Starship\u2019s validation chain for reusability and in-space propellant transfer. Source: Table created by the author based on publicly available SpaceX and NASA information.<\/div>\n<h2>4. Liquid Hydrogen Versus Liquid Methane Is More Than a Choice Between Two Fuels<\/h2>\n<p>The RS-25 and Raptor are both high-performance liquid-propellant rocket engines, but they serve different system-level objectives. The RS-25\u2019s liquid-hydrogen\/liquid-oxygen propellant combination delivers very high specific impulse, making it well suited to providing efficient thrust over an extended burn. SLS uses two solid rocket boosters to meet the high-thrust requirements of the initial ascent phase.[3][4]<\/p>\n<p>Raptor burns liquid methane and liquid oxygen using a full-flow staged-combustion cycle. Methane is denser than hydrogen and is stored at a much higher temperature, so it has different implications for tank volume and cryogenic-system layout. It is still a cryogenic propellant, however, and the real challenges lie in long-duration storage inside very large tanks, stabilizing fluids in microgravity, and enabling two vehicles to rendezvous, dock and conduct high-flow-rate propellant transfer.[6][8]<\/p>\n<p>Engine count is also a reflection of system architecture. SLS concentrates its thrust on a single deep-space injection mission by combining four RS-25 core-stage engines with two solid rocket boosters. Starship\u2019s first stage uses 33 Raptor engines to provide liftoff thrust, while thrust vectoring from its gimbaling engines and engine-restart capability also support ascent and return control. Clustering so many engines introduces greater complexity in propellant supply, control, fault management and the thermal environment at the base of the vehicle.<\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Different Propellants Reshape the Entire Rocket<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">Mixture ratio, density, cryogenic storage, engine configuration and reusability constraints are interdependent design parameters.<\/div>\n<table style=\"width: 100%; border-collapse: collapse; text-align: left; background-color: #ffffff; margin: 0; border-spacing: 0;\">\n<thead>\n<tr style=\"background-color: #3b74bf; color: #ffffff;\">\n<th style=\"width: 22%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">Design Factor<\/th>\n<th style=\"width: 39%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">SLS Core Stage<\/th>\n<th style=\"width: 39%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-bottom: 1px solid #0b3c85;\">Starship<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Propellants<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Liquid hydrogen and liquid oxygen<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Liquid methane and liquid oxygen<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Engines<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Four RS-25 engines<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">33 Raptor engines on the Super Heavy first stage<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Effect on Volume<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Hydrogen\u2019s low density requires large propellant tanks<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Methane is denser than hydrogen, but overall vehicle dimensions remain constrained by payload capacity and reusability requirements<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Thermal Management<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Hydrogen\u2019s extremely low temperature makes insulation and fueling systems more complex<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Methane also requires cryogenic handling; long-duration storage and propellant transfer in orbit are key challenges<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Liftoff Thrust<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Shared with two solid rocket boosters<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Multiple engines operate in parallel, with the propulsion system designed alongside first-stage return requirements<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"font-weight: 600; color: #1a202c; padding: 12px 14px; font-size: 15px; border-right: 1px solid #cbd5e1;\">Mission Focus<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1;\">One-time, high-energy deep-space transportation<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50;\">Reusability, high launch cadence and in-orbit refueling<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div style=\"background-color: #f1f5f9; padding: 14px 16px; font-size: 14px; color: #475569; border-top: 1px solid #cbd5e1; line-height: 1.6; text-align: left;\"><span style=\"display: block; color: #173f59; font-size: 16px; font-weight: 600; margin-bottom: 6px;\">Conclusion: There Is No \u201cOptimal Propellant\u201d in Isolation<\/span><br \/>\nA propellant\u2019s value must be assessed together with tank and engine design, ground fueling, mission delta-v, recovery method and operational cadence.<\/div>\n<\/div>\n<p><!-- Source --><\/p>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\">Table 4: How the propulsion systems of the SLS core stage and Starship influence the overall vehicles. Source: Table created by the author based on publicly available NASA and SpaceX information.<\/div>\n<h2>5. An Orange Aluminum Rocket and a Silver Stainless-Steel Rocket Reflect Two Different Manufacturing and Operating Systems<\/h2>\n<p>The liquid-hydrogen and liquid-oxygen tanks in the SLS core stage are made primarily from 2219 aluminum alloy. Its distinctive orange exterior comes from spray-on foam insulation. The foam reduces heat transfer between the cryogenic propellants and the surrounding environment while also helping the vehicle cope with condensation, ice formation and aerodynamic heating during flight.[5]<\/p>\n<p>Starship\u2019s primary structure and propellant tanks are made from stainless steel. This choice works in conjunction with SpaceX\u2019s welding processes, rapid iteration, large-scale manufacturing and vehicle-return requirements. Stainless steel does not automatically produce lower costs; it is simply one variable within the broader production and operating system.<\/p>\n<p>A material\u2019s density, strength, cryogenic properties and high-temperature performance all influence structural design. But whether a rocket can be built quickly, launched frequently and returned to service with minimal maintenance also depends on its thermal protection system, weld quality, nondestructive inspection, configuration management and reflight certification. Directly equating the two material choices with \u201cconservative\u201d and \u201cadvanced\u201d overlooks the most important system-engineering considerations.<\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Aluminum Alloy vs. Stainless Steel: Two Different Manufacturing Systems<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">Material selection is closely linked to tank dimensions, insulation, welding, production cadence and the atmospheric-return environment.<\/div>\n<table style=\"width: 100%; border-collapse: collapse; text-align: left; background-color: #ffffff; margin: 0; border-spacing: 0;\">\n<thead>\n<tr style=\"background-color: #3b74bf; color: #ffffff;\">\n<th style=\"width: 12%; padding: 12px 10px; font-size: 15px; font-weight: 600; text-align: center; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">No.<\/th>\n<th style=\"width: 44%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-right: 1px solid #ffffff; border-bottom: 1px solid #0b3c85;\">SLS Core Stage<\/th>\n<th style=\"width: 44%; padding: 12px 14px; font-size: 15px; font-weight: 600; border-bottom: 1px solid #0b3c85;\">Starship System<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">1<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Tanks made from 2219 aluminum alloy<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Stainless-steel structure and tanks<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">2<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Orange spray-on foam insulation<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Designed around a rapid manufacturing and iteration cycle<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">3<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\">Extra-large cryogenic propellant tanks<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-bottom: 1px solid #cbd5e1;\">Must withstand the thermal and aerodynamic loads of atmospheric return<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 12px 10px; font-size: 15px; font-weight: 600; color: #27718d; text-align: center; border-right: 1px solid #cbd5e1;\">4<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50; border-right: 1px solid #cbd5e1;\">The current design is based on single-use operation<\/td>\n<td style=\"padding: 12px 14px; font-size: 15px; line-height: 1.5; color: #2c3e50;\">Its reusability goal requires a closed loop of evidence from recovering and reflying the same vehicle<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div style=\"background-color: #123d63; padding: 16px 18px; color: #e2e8f0; font-size: 14px; line-height: 1.6; text-align: left;\"><span style=\"display: block; color: #ffffff; font-size: 16px; font-weight: 600; margin-bottom: 7px;\">Material Alone Cannot Predict Cost<\/span><br \/>\nAluminum alloys, stainless steel and composite materials can all be used to build high-performance structures. Cost and reusability ultimately depend on the combined effects of materials, structural design, thermal protection, inspection and maintenance, production organization and flight frequency.<\/div>\n<\/div>\n<p><!-- Source --><\/p>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\">Table 5: The material choices for SLS and Starship support different manufacturing and operating systems. Source: Table created by the author based on publicly available NASA and SpaceX information.<\/div>\n<h2>6. Recovery, Reflight and In-Space Refueling Are Three Separate Scorecards<\/h2>\n<p>As of the article\u2019s cutoff date, SpaceX had completed multiple Super Heavy returns and launch-tower catches. This has demonstrated that the first stage can return to the vicinity of the launch tower as planned. Assessing the system\u2019s economics, however, will require further evidence from repeated reflights of the same booster, the maintenance required between flights, turnaround time and operational availability.[6]<\/p>\n<p>Recovering the upper stage is even more difficult. It must reenter the atmosphere from orbital velocity, exposing it to more intense heat fluxes and a more complex flight envelope. Only after Starship can complete reliable reentries and recoveries\u2014and the same vehicle can fly again\u2014will \u201cupper-stage reusability\u201d move from a design objective to an operational capability.<\/p>\n<p>In-space propellant transfer represents another separate challenge. During Starship\u2019s third integrated flight test in 2024, SpaceX transferred liquid oxygen between tanks within a single vehicle. NASA TechPort subsequently recorded the demonstration as an on-orbit transfer of more than three metric tons of liquid oxygen between tanks. Rendezvous and docking between two vehicles, followed by the transfer of cryogenic propellant, remains a flight-validation milestone that the HLS architecture must still pass.[7][8]<\/p>\n<h2>7. The Difference Between SLS Reviews and Starship\u2019s Rapid Iteration Is Not Simply \u201cSafety\u201d Versus \u201cRisk-Taking\u201d<\/h2>\n<p>SLS follows NASA\u2019s process for crewed deep-space systems, including design reviews, component- and element-level testing, the core stage Green Run system-level hot-fire test campaign, and the collection of real-world data through the uncrewed Artemis I integrated flight test. The value of this approach lies in breaking down mission risks into layers and systematically resolving them in accordance with human-spaceflight requirements.[9]<\/p>\n<p>Starship also undergoes extensive ground testing, but it relies more frequently on large-scale integrated flight tests to expose system-level problems before changes are incorporated into the design and subsequent hardware. When an anomaly occurs, launch operations are also subject to public-safety reviews by regulators such as the FAA.[10]<\/p>\n<p>The difference between the two approaches lies in how test evidence is obtained, how risk is progressively addressed and how hardware is iterated. Once either system enters the crewed mission chain, it must ultimately demonstrate that its mission-specific configuration, flight envelope, fault-response capabilities and operating procedures meet applicable safety and mission requirements.<\/p>\n<div style=\"max-width: 800px; margin: 24px auto; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif; border: 1px solid #3b74bf; border-radius: 8px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,0.08);\">\n<div style=\"background-color: #0b3c85; color: #ffffff; font-size: 20px; font-weight: bold; text-align: center; padding: 16px; border-bottom: 1px solid #3b74bf;\">Two Engineering Paths, Both Requiring Closed-Loop Evidence<\/div>\n<div style=\"background-color: #f1f5f9; padding: 12px 16px; font-size: 14px; color: #475569; line-height: 1.5; text-align: center; border-bottom: 1px solid #cbd5e1;\">Development methods may differ, but the safety and mission-success requirements of crewed missions remain unchanged.<\/div>\n<table style=\"width: 100%; border-collapse: collapse; table-layout: fixed; text-align: center; background-color: #ffffff; margin: 0; border-spacing: 0;\">\n<thead>\n<tr>\n<th style=\"width: 50%; padding: 13px 14px; background-color: #d98224; color: #ffffff; font-size: 17px; font-weight: 600; border-right: 4px solid #ffffff;\">SLS\/Orion<\/th>\n<th style=\"width: 50%; padding: 13px 14px; background-color: #2999a0; color: #ffffff; font-size: 17px; font-weight: 600;\">Starship\/HLS<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-right: 4px solid #ffffff; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #e88b28; color: #ffffff;\">1<\/span>Design Reviews<\/td>\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #299da3; color: #ffffff;\">1<\/span>Ground-System Testing<\/td>\n<\/tr>\n<tr style=\"background-color: #ffffff;\">\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #d98224; border-right: 4px solid #ffffff;\">\u2193<\/td>\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #2999a0;\">\u2193<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-right: 4px solid #ffffff; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #e88b28; color: #ffffff;\">2<\/span>Component- and Element-Level Testing<\/td>\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #299da3; color: #ffffff;\">2<\/span>High-Cadence Integrated Flight Testing<\/td>\n<\/tr>\n<tr style=\"background-color: #ffffff;\">\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #d98224; border-right: 4px solid #ffffff;\">\u2193<\/td>\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #2999a0;\">\u2193<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-right: 4px solid #ffffff; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #e88b28; color: #ffffff;\">3<\/span>Core Stage Green Run Hot-Fire Test<\/td>\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #299da3; color: #ffffff;\">3<\/span>First-Stage Return and Reflight<\/td>\n<\/tr>\n<tr style=\"background-color: #ffffff;\">\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #d98224; border-right: 4px solid #ffffff;\">\u2193<\/td>\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #2999a0;\">\u2193<\/td>\n<\/tr>\n<tr style=\"background-color: #f8fafc;\">\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-right: 4px solid #ffffff; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #e88b28; color: #ffffff;\">4<\/span>Artemis I Uncrewed Integrated Flight Test<\/td>\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-top: 1px solid #cbd5e1; border-bottom: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #299da3; color: #ffffff;\">4<\/span>In-Orbit Propellant Transfer Between Two Vehicles<\/td>\n<\/tr>\n<tr style=\"background-color: #ffffff;\">\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #d98224; border-right: 4px solid #ffffff;\">\u2193<\/td>\n<td style=\"padding: 3px; font-size: 24px; line-height: 1; font-weight: bold; color: #2999a0;\">\u2193<\/td>\n<\/tr>\n<tr style=\"background-color: #edf2f7;\">\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-right: 4px solid #ffffff; border-top: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #e88b28; color: #ffffff;\">5<\/span>Crewed-Mission Data Feedback Loop<\/td>\n<td style=\"padding: 14px; font-size: 15px; font-weight: 600; color: #1a202c; border-top: 1px solid #cbd5e1;\"><span style=\"display: inline-block; min-width: 28px; margin-right: 8px; padding: 5px 2px; border-radius: 50%; background-color: #299da3; color: #ffffff;\">5<\/span>Uncrewed HLS Lunar-Landing Demonstration<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p><!-- Source --><\/p>\n<div style=\"max-width: 800px; margin: 6px auto 18px; font-size: 13px; line-height: 1.5; color: #64748b; font-style: italic;\">Table 6: The validation chains for SLS\/Orion and Starship\/HLS. Source: Table created by the author based on publicly available information from NASA, SpaceX and the FAA.<\/div>\n<p>When evaluating SLS, the key questions are whether it can complete its launch mission within the required window for crewed deep-space exploration, and whether its flight reliability, mission cadence, per-launch cost and supply chain can remain under control. The significance of SLS does not depend on whether it can be recovered as quickly as Starship, because its current baseline configuration is designed for expendable missions.<\/p>\n<p>When evaluating Starship, the focus should be on whether its design objectives can be converted into repeatable operational data: Can both the first stage and upper stage be recovered reliably? How quickly can the same vehicle fly again? Can Starships conduct large-scale cryogenic propellant transfer in orbit? Can HLS complete an uncrewed lunar landing demonstration?<\/p>\n<p><strong>In one sentence:<\/strong> SLS begins with the objective of a single crewed deep-space launch, while Starship begins with reusability and large-scale space transportation. Their propellants, engines, structural materials and testing methods are all extensions of those different starting points. To understand a rocket, the most useful first question is always the same: What mission is it actually designed to accomplish?<\/p>\n<p>As lunar and deep-space missions become increasingly complex system-engineering projects, launch capability is only one part of the equation. China\u2019s expanding satellite industry is bringing greater production capacity and more cost-competitive spacecraft, payload and Assembly, Integration and Test (AIT) solutions to the global market. International customers developing new space missions can <a href=\"https:\/\/starpath.global\/contact\">contact STARPATH GLOBAL<\/a> to identify suitable capabilities and build a practical, cost-efficient path from mission concept to delivery.<\/p>\n<h2>References<\/h2>\n<p>[1] NASA, <em>How NASA\u2019s Artemis III Lander Test Will Pave Way for Moon Landings<\/em>, July 15, 2026; NASA, <em>Artemis III News and Updates<\/em>, 2026.<\/p>\n<p>[2] NASA, <em>Space Launch System Reference Guide<\/em>; NASA, <em>Space Launch System RS-25 Core Stage Engine<\/em>, March 24, 2026.<\/p>\n<p>[3] NASA, <em>SLS Space Launch System Solid Rocket Booster<\/em>, publicly available information on the five-segment solid rocket booster.<\/p>\n<p>[4] NASA, <em>Space Launch System RS-25 Core Stage Engine<\/em>, MSFC-12-2025-SLS-5637, 2026.<\/p>\n<p>[5] NASA, <em>SLS Space Launch System Core Stage<\/em>, January 22, 2026.<\/p>\n<p>[6] SpaceX, <em>Starship Vehicle Overview and Updates<\/em>, as of September 11, 2026.<\/p>\n<p>[7] NASA, <em>NASA Artemis Mission Progresses with SpaceX Starship Test Flight<\/em>, updated June 22, 2026.<\/p>\n<p>[8] NASA TechPort, <em>On-Orbit Large-Scale Cryogenic Propellant Management and Transfer Demonstration<\/em>, updated July 15, 2026.<\/p>\n<p>[9] NASA, publicly available materials on the SLS Green Run test series and the Artemis I integrated flight test.<\/p>\n<p>[10] Federal Aviation Administration, publicly available materials on SpaceX Starship\/Super Heavy licensing and mishap response, as of September 11, 2026.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>On one side is the orange-and-white SLS. On the other is Starship, resembling a stainless-steel tower. Both are part of the United States\u2019 architecture for returning humans to the Moon, yet they have almost nothing in common\u2014from their appearance and engines to how they are intended to operate. Their respective roles: SLS Block 1 and [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":89580,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[3],"tags":[304,800,572,190,640,238,624,316,317,5841],"class_list":["post-89557","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-artemis","tag-human-landing-system","tag-lunar-exploration","tag-nasa","tag-orion","tag-reusable-rockets","tag-sls","tag-spacex","tag-starship","tag-united-states"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/89557"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=89557"}],"version-history":[{"count":4,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/89557\/revisions"}],"predecessor-version":[{"id":89589,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/89557\/revisions\/89589"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/89580"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=89557"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=89557"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=89557"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}