# How The Space Shuttle Worked | Full Documentary

Channel: Real Engineering
Source: https://www.youtube.com/watch?v=w4FCkbPykdQ
Recap page: https://rapidrecap.app/video/w4FCkbPykdQ

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## Quick Overview

The Space Shuttle was a revolutionary reusable space plane, powered by three main liquid-fuel engines and two massive solid rocket boosters, designed for complex missions like satellite rescue. Its intricate engineering included unique fuel management, precise thrust vectoring, and a sophisticated reaction control system, all managed by fly-by-wire computers, with a notable manual override for landing gear deployment. The STS-49 mission successfully rescued a stranded Intelsat satellite through an unprecedented three-person spacewalk and the precise operation of the Canadarm, overcoming initial capture failures and thermal warping issues with the payload bay doors.

**Key Points:**
- The Space Shuttle launched with three main liquid-fuel engines and two solid rocket boosters (SRBs), which were the largest ever made, each providing 13,000 kilonewtons of thrust.
- The SRBs, once ignited, could not be throttled or stopped, and their fuel cavity was shaped with an 11-point star in the upper section to control thrust, reducing it by 33% 50 seconds into flight.
- At 2 minutes into flight, the SRBs separated from the external tank, a process astronaut Bruce Melnick described as a 'big bang and then you're in this Fireball' due to the exhaust from separation motors.
- The external tank was the largest design compromise, being a non-reusable structural backbone that contained liquid oxygen (LOX) and liquid hydrogen (LH2), with LOX placed on top to raise the center of gravity for stability.
- The STS-49 mission successfully rescued a stranded Intelsat satellite after initial capture attempts failed, leading to an unprecedented three-person spacewalk to manually grab the satellite.
- Astronaut Bruce Melnick, a Coast Guard helicopter pilot, expertly operated the 15-meter Canadarm, which could move 30 tons in orbit despite weighing only 430 kg, to secure the capture bar to the satellite.
- The Orbiter's payload bay doors, made of graphite epoxy composite, initially failed to latch on STS-49 due to thermal warping, but the crew resolved this by orbiting in 'barbecue mode' to equalize temperatures.

**Context:** The Space Shuttle program aimed for reusability, but faced funding challenges that led to design compromises, such as the expendable external tank. The documentary details the complex engineering behind the shuttle's operation, from its powerful launch systems to its precise orbital maneuvering capabilities. A key focus is the STS-49 mission aboard the Space Shuttle Endeavour, its maiden flight in 1992, which involved a daring rescue of a stranded Intelsat communication satellite that had failed to reach its intended geosynchronous orbit.

## Detailed Analysis

The Space Shuttle, a groundbreaking reusable space plane, launched with immense power from three main liquid-fuel engines and two solid rocket boosters (SRBs), the largest ever made. The launch sequence involved the main engines igniting first, causing a 'twang' as the stack bent, followed by the SRBs at T-0. SRBs, fueled by a rubbery mixture of ammonium perchlorate and aluminum, used a 40-point star igniter for rapid combustion and featured an 11-point star internal cavity to manage thrust profiles, reducing it by 33% 50 seconds into flight. Hold-down posts with explosive frangible nuts anchored the shuttle, with a redesign implemented after 'stud Hang-Ups' were observed. Two minutes into flight, SRBs separated with a 'big bang' and exhaust fireball, propelled by separation motors. The external tank, a non-reusable structural backbone, contained liquid oxygen (LOX) and liquid hydrogen (LH2), with LOX placed on top for stability. Fuel was fed to the Orbiter via massive pipes and umbilical plates, with gaseous lines maintaining ullage pressure. Main engine cut-off (MECO) was triggered by velocity or fuel sensors, ensuring a fuel-rich shutdown to protect reusable engines. After MECO, the external tank separated, and critical umbilical doors closed. In orbit, the Orbiter used its Orbital Maneuvering System (OMS) for large velocity changes and a Reaction Control System (RCS) with 44 hypergolic thrusters for precise attitude and translational control, managed by a fly-by-wire computer system, except for the manually deployed landing gear. The Orbiter's windows featured multiple layers for pressure and thermal resistance. The STS-49 mission, Endeavour's maiden flight, aimed to rescue a stranded Intelsat satellite. After initial failures to capture the satellite with a bar, astronauts devised an unprecedented three-person spacewalk, utilizing components from three EVA suits, to manually grab the satellite. Bruce Melnick, a Coast Guard helicopter pilot, expertly operated the Canadarm, a 15-meter composite arm capable of moving 30 tons in orbit, to secure the capture bar to the satellite, enabling its re-orbiting. Life support systems included oxygen and nitrogen tanks, lithium hydroxide canisters for CO2 scrubbing, and fuel cells for power and water production. The mission also faced a challenge with payload bay doors not latching due to thermal warping, which was resolved by orbiting in 'barbecue mode' to equalize temperatures.

### Space Shuttle Launch Sequence

- Three main liquid-fuel engines ignite first, causing a 'twang'
- Two solid rocket boosters (SRBs) ignite at T-0, providing 13,000 kilonewtons of thrust each
- SRBs use a rubbery fuel mixture with an 11-point star internal cavity for controlled thrust reduction
- Eight explosive frangible nuts on hold-down posts anchor the shuttle, with a redesign addressing 'stud Hang-Ups'
- SRBs separate at 2 minutes into flight, propelled by 96,000 Newtons of thrust from separation motors

### External Tank and Fuel Management

- The external tank is a non-reusable structural backbone connecting the Orbiter and SRBs
- It contains liquid oxygen (LOX) on top for stability and liquid hydrogen (LH2) below
- Massive pipes and umbilical plates transfer fuel to the Orbiter's main engines
- Gaseous lines maintain ullage pressure in the tanks, vital for structural integrity
- Main engine cut-off (MECO) is triggered by velocity or fuel sensors, ensuring a fuel-rich shutdown to protect reusable engines

### Orbital Maneuvering and Control Systems

- The Orbital Maneuvering System (OMS) provides 305 m/s of additional velocity for large orbital changes
- The Reaction Control System (RCS) uses 44 hypergolic thrusters for precise attitude and translational control
- Hypergolic fuels spontaneously ignite on contact, offering reliability and long storage
- Control is primarily fly-by-wire, with the landing gear being the only mechanical link due to concerns about cosmic ray interference
- Astronauts control the Orbiter using a square knob for translation and a flight stick for attitude, with a rear station for rendezvous maneuvers

### Orbiter Design and Internal Systems

- Multi-layered windows provide pressure and thermal resistance, with a 33mm thick fused silica redundant pane
- The payload bay doors, made of graphite epoxy composite, open in orbit to expose radiator panels for temperature control
- Life support includes oxygen and nitrogen tanks for breathable atmosphere and lithium hydroxide canisters for CO2 scrubbing
- Fuel cells generate electricity and water from hydrogen and oxygen, with water undergoing degassing before use
- Astronauts sleep strapped to walls or in cloth sleeping bags in the mid-deck, where science experiments are also performed

### STS-49 Satellite Rescue Mission

- The Endeavour's maiden flight aimed to rescue a stranded Intelsat satellite in a useless 800-mile orbit
- Initial attempts to capture the satellite with a capture bar failed as it bounced off
- Astronauts devised an unprecedented three-person spacewalk, utilizing components from three EVA suits, to manually grab the satellite
- Bruce Melnick, a Coast Guard helicopter pilot, expertly operated the 15-meter Canadarm to secure the capture bar to the satellite
- The mission successfully attached a new second stage to the satellite, allowing it to reach geostationary orbit and operate for 21 years

### Mission Challenges and Solutions

- The STS-93 mission experienced a hydrogen leak due to an ejected gold pin, leading to a maintenance policy change for oxygen posts
- STS-49 faced an issue with payload bay doors not latching due to thermal warping
- The crew resolved the payload door issue by orbiting in 'barbecue mode' to equalize temperatures
- The airlock, designed for two, accommodated three spacewalkers by having one astronaut positioned upside down on internal life support systems
- The manual capture of the Intelsat satellite required precise coordination and adaptation after initial failures