A service structure is a permanent

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

framework or tower erected on a

rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

launch pad that allows assembly, servicing, and crew onboarding of the

launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...

prior to liftoff. In

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

launches at the

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...

, astronauts enter the vehicle through a type of service structure called an " umbilical tower". Immediately before ignition of the rocket's

engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

, all connections between the tower and the craft are severed, and the connecting

bridges A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somet ...

swing away to prevent damage to structure and vehicle. An elevator in the tower also allows maintenance crew to service the vehicle.

Kennedy Space Center

During the NASA Space Shuttle program, the structures at the

Launch Complex 39 Launch Complex 39 (LC-39) is a rocket launch site at the John F. Kennedy Space Center on Merritt Island, Florida, Merritt Island in Florida, United States. The site and its collection of facilities were originally built as the Apollo program's ...

pads contained a two-piece access tower system, the Fixed Service Structure (FSS) and the Rotating Service Structure (RSS). The FSS permitted access to the Shuttle via a retractable arm and a "beanie cap" to capture vented liquid oxygen (LOX) from the external fuel tank. The RSS contained the Payload Changeout Room, which offered "clean" access to the orbiter's payload bay, protection from the elements, and protection in winds up to . The FSS on Pad 39A was repurposed the top of the umbilical tower of Mobile Launcher 2, while the FSS on 39B re-used the umbilical tower of Mobile Launcher 3. Mobile Launcher 3 would later become Mobile Launcher Platform 1 for the Shuttle. In 2011 NASA removed both the FSS and RSS from LC-39B to make way for a new generation of launch vehicles. In 2017-2018

SpaceX Space Exploration Technologies Corp., commonly referred to as SpaceX, is an America, American space technology company headquartered at the SpaceX Starbase, Starbase development site in Starbase, Texas. Since its founding in 2002, the compa ...

removed the RSS from LC-39A and modified the FSS for its new series of launch vehicles. Certain rockets such as the

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), the fourth letter of the Greek alphabet * D (NATO phonetic alphabet: "Delta"), the fourth letter in the Latin alphabet * River delta, at a river mouth * Delta Air Lines, a major US carrier ...

and the Saturn V use structures consisting of a fixed portion and a mobile portion; the former is the umbilical tower and the latter is known as the "mobile service tower" or "mobile service structure," but often referred to as a '' gantry''. This mobile structure is moved away from the vehicle several hours before launch.

White room

The white room was the small area used by astronauts to access the spacecraft during human flights up through the Space Shuttle program. The room takes its name from its white paint, which was used in Project Gemini. The room was first used in Project Mercury. Its use and white color (since Gemini) continued through subsequent programs of Apollo and the Space Shuttle. Astronauts and closeout crew made their final preparations before liftoff, such as donning

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

packs, putting on

spacesuit A space suit (or spacesuit) is an environmental suit used for protection from the harsh Space environment, environment of outer space, mainly from its Vacuum (outer space), vacuum as a highly specialized pressure suit, but also its temperatu ...

helmets, and detaching portable air-conditioning units. In 2014, NASA planned to move the White Room to a museum. SpaceX launches use a rotating "Crew Access Arm" for . As of the 2020 Crew Dragon Demo-2 mission, SpaceX began calling the equivalent area of its Crew Access Arm at LC-39A the "White Room" in recognition of the original NASA structure's significance. On the first launch attempt, NASA and SpaceX flight crew began signing their respective "meatball"

NASA insignia The NASA has three official insignia, insignias, although the one with stylized red curved text (the "worm") was retired from official use from May 22, 1992, until April 3, 2020, when it was reinstated as a secondary logo. The three logos include ...

or SpaceX logos at the end of the Crew Access Arm, a practice which has become a tradition.

Baikonur Cosmodrome

Similarly, Soviet-and Russian-designed service structures such as those at

Baikonur Cosmodrome The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...

Site 31 feature rotating crane-like "tower arms" that stand upright to service and secure the vehicle. The tower arms then pivot outward away from the rocket at launch. https://blogs.esa.int/eolaunches/2012/09/14/metop-on-the-launch-pad/

References

{{Space Shuttle Rocket launch technologies Apollo program hardware Space Shuttle program