The Space Shuttle's Ascent: Pradhuman Chahar

 

The Space Shuttle's Ascent 

Hey readers, Pradhuman here today we will learn about Space shuttle path to orbit

As the Space Shuttle powers its way through the atmosphere, propelled by its massive solid rocket boosters and main engines, the astronauts inside the orbiter transition from an exhilarating thundering journey to a serene, silent cruise. The moment the engines power down, they become weightless, and the light of the shining blue Earth below floods through the windows of the crew cabin. The journey to orbit has ended, but their mission has just begun.

The Space Shuttle was not just a rocket - it was a mobile laboratory, a home in space, equipped with all the tools the astronauts needed to not just survive, but to complete complicated tasks in space. The orbiter provided a secure haven, sustaining a breathable atmosphere, facilitating precise maneuvers, and housing a payload bay capable of carrying massive spacecraft like the Hubble Space Telescope.

The Reaction Control System

The astronauts' jobs begin the moment they reach orbit. The orbiter has released the external tank, and it's beginning its journey back through the atmosphere where it will disintegrate. To inspect the tank for any issues that could have occurred on ascent, the commander of the orbiter needs to pitch the shuttle onto its back using its maneuvering system.

Scattered all over the orbiter are smaller rocket nozzles, part of the reaction control system. This removable module in the nose of the aircraft contains two spherical tanks - one filled with nitrogen tetroxide (the oxidizer) and the other with monomethyl hydrazine (the fuel). This hypergolic fuel-oxidizer combination ignites spontaneously upon contact, providing precise and instantaneous thrust control for delicate maneuvering and docking procedures.

The reaction control system features 38 main thrusters, each capable of providing 3,870 newtons of thrust, as well as 6 smaller vernier thrusters for even finer control. The astronauts control these thrusters using a square-knobbed controller for translational movements and a traditional flight stick for attitude adjustments, all of which are fed into a fly-by-wire computer system.

The Orbiter's Windows and Thermal Protection System

The Space Shuttle's windows were a critical component, designed to be durable enough to survive space debris impacts and capable of resisting the extreme temperatures of re-entry. The window structure had multiple layers of glass, each tailored to withstand different conditions. The pressure pane was made from tempered aluminosilicate glass, the outer thermal pane could resist temperatures up to 482 degrees Celsius, and a thick, redundant center pane made of fused silica glass served as a failsafe.

The rear windows looking into the payload area did not have the outer thermal pane, as they would not be exposed to the super-heated plasma during re-entry. The middeck, where the astronauts slept and performed experiments, had no windows at all.

The Payload Bay and Temperature Control

The payload bay doors needed to open shortly after reaching orbit, as one of the Space Shuttle's vital life support systems required them to be open. The temperature control system used freon-filled tubes snaking around radiator panels attached to the payload bay doors to radiate heat absorbed from a heat exchanger inside the orbiter into space.

The payload bay doors themselves were made from a lightweight graphite/epoxy composite material, covering an area 18.3 meters long and 4.6 meters wide - the largest and heaviest payload the Shuttle ever carried was the 22.7-tonne Chandra X-Ray Observatory.

Rendezvous and Docking Procedures

Once the Space Shuttle has arrived at its target orbit, the real work can begin. On Bruce's mission, STS-49, the first task was to rendezvous with a stranded communications satellite. As the astronauts approached, two of them donned their EVA suits in the middeck and prepared to enter the airlock.

The airlock was located inside the crew cabin, but it could be configured to be outside in the payload area. During the construction of the International Space Station, a special docking system called the Androgynous Peripheral Attach System was installed, allowing the Space Shuttle to dock with both Russian and American spacecraft.

On STS-49, the stranded satellite had no docking points, so the astronauts needed to perform an EVA and manually grab the satellite using a capture bar. This proved to be a challenging task, as the satellite kept bouncing off the capture bar. After several failed attempts, the crew came up with a creative solution - they would send three astronauts out instead of the usual two, with one person attaching the capture bar while the other two grabbed the satellite with their gloved hands.

The Canadarm and Orbital Maneuvering System

The Canadarm, a 15-meter long articulated arm, was a multifunctional tool used for many tasks aboard the Shuttle. Despite weighing just 430 kilograms, it could move 30 tonnes in orbit. The arm's unique design, with 6 degrees of freedom, allowed for precise and delicate movements, even in the weightless environment of space.

The Shuttle also had an Orbital Maneuvering System, with large rocket nozzles capable of providing 305 meters per second of additional velocity. This system, powered by the same hypergolic fuel and oxidizer as the Reaction Control System, was used for larger orbital changes.

Life Support Systems and Re-entry

The Space Shuttle's life support systems included spherical tanks of high-pressure oxygen and nitrogen, used to create a breathable atmosphere, as well as a fuel cell that generated electricity and water. The cabin air was scrubbed of carbon dioxide using lithium hydroxide canisters, which needed to be replaced every 12 hours.

As the Shuttle prepared for re-entry, the payload bay doors needed to be closed, but on STS-49, they wouldn't latch properly due to thermal warping. The crew had to use a "barbecue mode" to equalize the temperatures on the Shuttle before they could successfully close the doors.

During re-entry, the Space Shuttle would be traveling between 7 and 8 km/s, entering the thin upper atmosphere at 30 times the speed of sound. The incredible heat, reaching 1,650 degrees Celsius, required innovative engineering to not only withstand but also transition the Shuttle into a glider capable of landing on a runway - a true space plane.

The insane engineering of the Space Shuttle Orbiter is a testament to the ingenuity and dedication of the teams that designed and built this remarkable vehicle. From its ascent to orbit, to its complex systems and procedures, the Space Shuttle represented a groundbreaking leap in aerospace technology and exploration.