Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

The orbiter is the most important section of the Space Shuttle. Although it looks a great deal like a small plane, it is actually a high-tech laboratory and storage area, with facilities to hold up to seven crew members for over two weeks. The front end of the orbiter is comprised of three levels: the flight deck, the mid-deck, where the crews live whilst in space, and the lower deck, which contains vital life-support equipment. Most of the orbiter is taken up by a vast payload bay.

The Orbiter is both the brains and heart of the Space Transportation System. About the same size and weight as a DC-9 aircraft, the Orbiter contains the pressurized crew compartment (which can normally carry up to seven crew members), the huge cargo bay, and the three main engines mounted on its aft end. The cockpit, living quarters and experiment operator’s station are located in the forward fuselage of the Orbiter vehicle. Payloads are carried in the mid-fuselage payload bay, and the Orbiter’s main engines and maneuvering thrusters are located in the aft fuselage.

The cockpit, living quarters and experiment operator’s station are located in the forward fuselage. This area houses the pressurized crew module and provides support for the nose section, the nose gear and the nose gear wheel well and doors.

The 65.8-cubic-meter (2,325-cubic-foot) crew station module is a three-section pressurized working, living and stowage compartment in the forward portion of the Orbiter. It consists of the flight deck, the middeck/equipment bay and an airlock. Outside the aft bulkhead of the crew module in the payload bay, a docking module and a transfer tunnel with an adapter can be fitted to allow crew and equipment transfer for docking, Spacelab and extravehicular operations. The two-level crew module has a forward flight deck with the commander’s seat positioned on the left and the pilot’s seat on the right.

The flight deck is designed in the usual pilot/copilot arrangement, which permits the vehicle to be piloted from either seat and permits one-man emergency return. Each seat has manual flight controls, including rotation and translation hand controllers, rudder pedals and speed-brake controllers. The flight deck seats four. The on-orbit displays and controls are at the aft end of the flight deck/crew compartment. The displays and controls on the left are for operating the Orbiter, and those on the right are for operating and handling the payloads. More than 2,020 separate displays and controls are located on the flight deck.

Six pressure windshields, two overhead windows and two rear-viewing payload bay windows are located in the upper flight deck of the crew module, and a window is located in the crew entrance/exit hatch located in the midsection, or deck, of the crew module.

The middeck contains provisions and stowage facilities for four crew sleep stations. Stowage for the lithium hydroxide canisters and other gear, the waste management system, the personal hygiene station and the work/dining table is also provided in the middeck. The nominal maximum crew size is seven. The middeck can be reconfigured by adding three rescue seats in place of the modular stowage and sleeping provisions. The seating capacity will then accommodate the rescue flight crew of three and a maximum rescued crew of seven.

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The STS is comprised of four main parts: the orbiter is the main section of the Shuttle, housing the crew, the control centre and the payload. The orbiter is the only part of the Shuttle to reach orbit, after which it returns to Earth, landing like a plane. An external fuel tank contains the liquid hydrogen and liquid oxygen needed for propulsion. Two solid rocket boosters propel the orbiter to a height of 45km (28 miles) before they are jettisoned.

Orbiter: Each orbiter is 121 feet long, with a wingspan of 78 feet and a tail height of 57 feet. Constructed mainly of aluminum, it is about the size of a DC-9 commercial airliner, and can carry a payload of 65,000 pounds into space. The payload bay is 60 feet long and 15 feet in diameter. The landing weight varies from mission to mission and ranges from 200,000 pounds to 230,000 pounds. Each orbiter is designed for a lifetime of about 100 space missions. The forward fuselage houses the cockpit and crew cabin and crew work areas. The mid-fuselage area consists of the payload bay and the wing and main landing gear attach points. The aft fuselage houses the main engines, the orbital maneuvering system (OMS), the reaction control system (RCS) pods, the wing aft spar, and the attach point for the vertical tail.

Main Engines: The main engines operate on a mixture of liquid oxygen and liquid hydrogen, each engine producing a sea level thrust of 375,000 pounds and a vacuum thrust of 470,000 pounds. The engines can be throttled over a thrust range of 65 to 109 percent, allowing a high power setting during liftoff and initial ascent, and a power reduction during final ascent to keep acceleration of the orbiter at three earth gravities. The engines are gimbaled (movable) to control pitch, yaw, and roll. Normal engine operating time on each flight is about 8.5 minutes. Each engine is designed for about 7.5 total operating hours.

External Tank: The external tank is 154 feet long and 28.6 feet in diameter. It is constructed primarily of aluminum alloys. Empty weight of an external tank is 78,100 pounds. When filled and flight ready, each has a gross weight of 1,667,677 pounds and contains nearly 1.6 million pounds (143,060 gallons) of liquid oxygen and more than 226,000 pounds (526,126 gallons) of liquid hydrogen. The external tank is the only major part of the space shuttle system not reused after each flight.

Solid Rocket Boosters: The space shuttle solid rocket boosters are the largest solid propellant motors ever built and the first to be used on a manned spacecraft. Each motor is made of 11 individual weld-free steel segments joined together with high-strength steel pins. Each assembled motor is 116 feet long, 12 feet in diameter, and contains more than l million pounds of solid propellant. The propellant burns at a temperature of 5,800 degrees Fahrenheit and generates a liftoff thrust of 2.65 million pounds. The exhaust nozzles are gimbaled to provide yaw, pitch, and roll control to help steer the orbiter on its ascent path. The solid propellant is made of atomized aluminum powder (fuel), ammonium perchlorate (oxidizer), iron oxide powder (catalyst), plus a binder and curing agent. The boosters burn for two minutes in parallel with the main engines during initial ascent and give the added thrust needed to achieve orbital altitude. After two minutes of flight, at an altitude of about 28 miles, the booster casings separate from the external tank. They descend by parachute into the Atlantic Ocean where they are recovered by ship, returned to land, and refurbished for reuse.

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Most rockets either burn up in Earth’s atmosphere or are decommissioned after they have completed their mission. A new rocket has to be built from scratch for the next launch. All but one part of NASA’s Space Shuttle returns to Earth intact. After these parts have been checked for damage, they are ready to be used again, therefore saving the cost of rebuilding.

The U.S. space shuttle consisted of three major components: a winged orbiter that carried both crew and cargo; an external tank containing liquid hydrogen (fuel) and liquid oxygen (oxidizer) for the orbiter’s three main rocket engines; and a pair of large, solid-propellant, strap-on booster rockets. At liftoff the entire system weighed 2 million kilograms (4.4 million pounds) and stood 56 metres (184 feet) high. During launch the boosters and the orbiter’s main engines fired together, producing about 31,000 kilonewtons (7 million pounds) of thrust. The boosters were jettisoned about two minutes after liftoff and were returned to Earth by parachute for reuse. After attaining 99 percent of its orbital velocity, the orbiter had exhausted the propellants in the external tank. It released the tank, which disintegrated on reentering the atmosphere. Although the orbiter lifted off vertically like an expendable rocket launcher, it made an unpowered descent and landing similar to a glider.

The space shuttle could transport satellites and other craft in the orbiter’s cargo bay for deployment in space. It also could rendezvous with orbiting spacecraft to allow astronauts to service, resupply, or board them or to retrieve them for return to Earth. Moreover, the orbiter could serve as a space platform for conducting experiments and making observations of Earth and cosmic objects for as long as about two weeks. On some missions it carried a European-built pressurized facility called Spacelab, in which shuttle crew members conducted biological and physical research in weightless conditions.

The space shuttle launched like a rocket. But it landed like a glider airplane. The solid rocket boosters and the main engines on the orbiter helped the shuttle blast off from Earth like a rocket. The two boosters dropped off the shuttle two minutes after launch. They fell into the ocean. A special boat picked the boosters out of the ocean. They were used again for another flight. The external tank dropped off the orbiter after it had used all the fuel in the tank. The external tank would burn up over Earth. So the tank could not be used again.

When the shuttle orbiter returned to Earth, it came down from the sky like an airplane. Wheels came out from underneath the orbiter. It rolled to a stop on a runway. Then NASA would prepare it to fly on another mission.

On Apollo 17, the last manned mission to the Moon, the astronauts took with them a small buggy called the Lunar Rover. It was battery powered and could travel at just under 20k-min. (12mph), enabling astronauts to explore much more of the Moon than their predecessors had been able to do on foot. It had a small television camera and a satellite dish that sent the footage back to Earth. The Moon Buggy, as it is often called, had rubber tyres that could not be punctured, and was steered by a small hand control. It could be folded up and stored away when it was not needed.

The Apollo lunar roving vehicle was a battery-powered space buggy. The astronauts on Apollo 15, 16, and 17 used it to explore their landing sites and to travel greater distances than astronauts on earlier missions. The lunar rover neatly folded up inside the lunar lander during trips to the Moon. Once on the Moon’s surface, it unfolded with the help of springs. The lunar rover carried two astronauts and was manually driven. It was designed to climb steep slopes, to go over rocks, and to move easily over the Moon’s regolith. It was able to carry more than twice its own weight in passengers, scientific instruments, rocks, and regolith samples. The wheels on the rover were made of wire mesh (piano wire) with titanium cleats for treads. Engineers did not use solid or air-filled rubber tires because they would have been much heavier than were the wire mesh wheels. The Apollo spacecraft had a fixed amount of mass (payload) it could deliver to the surface, including the rover, rover batteries, scientific instruments, sample collection devices, etc. Hence, the wire-mesh wheels were important to the overall payload mass. This rover was not designed for prolonged use, and it is uncertain if future lunar explorers would use similar designs and materials for their vehicles, use new, more durable components, or turn to robotic rovers.

The LRV (Lunar Roving Vehicle) was technically a car, in that it had four wheels and two seats. Fenders over the wheels kept dust from flying everywhere, and the suspension incorporated double-swing A-arms, so overall it had a rather car-like look. Otherwise, it was radically different, starting with the exposed aluminum frame that was completely absent of bodywork. It also had no interior or even traditional controls like pedals and a steering wheel. A simple T-lever accessible by either astronaut was used to control turning, acceleration, and braking.

It did have four wheels, but instead of using solid rubber tires, a metallic mesh tire was developed using aluminum wires. Small titanium blocks arranged in a V-shape served as the tread, and it worked extremely well on the Moon’s very fine, powder-like surface.

They didn’t absorb impacts quite like air-filled tires, but astronauts remained secure in the LRV (Lunar Roving Vehicle) thanks to Velcro straps that kept them in the seats. To ensure the LRV (Lunar Roving Vehicle) could traverse the decidedly off-road environment on the Moon’s surface, four DC electric motors were installed in each wheel. That’s right – the LRV (Lunar Roving Vehicle) is a four-wheel-drive EV not unlike many modern electric hypercars, but it’s not nearly as powerful. Each motor produced the equivalent of just 0.25 horsepower. That power was transmitted to the wheels through a cycloidal gearbox with an 80:1 ratio, which allowed the rover to reach a top speed of approximately 8 mph (14 km/h).

Unlike modern EVs, the LRV was not rechargeable. Electricity was supplied via two zinc-silver batteries weighing a total of 119 pounds (54 kilograms). Total output was 8.7 kWh, and the LRV range was just 56 miles (90 kilometers). Another interesting tidbit about the individually-powered wheels is that all four could turn, giving the LRV a turning radius of just 9.8 feet (3 meters).

Sending a rocket into space is a very expensive procedure, especially considering that each launcher can be used only once. The Space Transportation System (STS), better known as the Space Shuttle, was designed to be the world’s first reusable space vehicle.

The Space Transportation System, also known internally to NASA as the Integrated Program Plan (IPP), was a proposed system of reusable manned space vehicles envisioned in 1969 to support extended operations beyond the Apollo program. (NASA appropriated the name for its Space Shuttle Program, the only component of the proposal to survive Congressional funding approval). The purpose of the system was twofold: to reduce the cost of spaceflight by replacing the current method of launching capsules on expendable rockets with reusable spacecraft; and to support ambitious follow-on programs including permanent orbiting space station around the Earth and Moon, and a human landing mission to Mars.

In February 1969, President Richard Nixon appointed a Space Task Group headed by Vice President Spiro Agnew to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human Mars landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system’s major components consisted of:

The tug and ferry vehicles would be of a modular design, allowing them to be clustered and/or staged for large payloads or interplanetary missions. The system would be supported by permanent Earth and lunar orbital propellant depots. The Saturn V might still have been used as a heavy lift launch vehicle for the nuclear ferry and space station modules. A special “Mars Excursion Module” would be the only remaining vehicle necessary for a human Mars landing.

As Apollo accomplished its objective of landing the first men on the Moon, political support for further manned space activities began to wane, which was reflected in unwillingness of the Congress to provide funding for most of these extended activities. Based on this, Nixon rejected all parts of the program except the Space Shuttle, which inherited the STS name. As funded, the Shuttle was greatly scaled back from its planned degree of reusability, and deferred in time. The Shuttle first flew in 1981, and was retired in 2011.

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There have been six Apollo missions to the Moon, during which 12 astronauts have explored its composition and conditions. Thousands of photographs have been taken, and 176kg (3881bs) of Moon-rock were brought back to Earth to be studied. Scientists are interested in finding out what the Moon is made of because this may determine its origin and history. Astronauts also measured the amount of solar particles reaching the lunar surface, the amount of dust in the air, and the power of moonquakes, which are slight movements in the Moon’s crust.

After the Lunar Module landed on the Moon’s Sea of Tranquility, Aldrin and Armstrong conducted a series of landmark scientific experiments. Aldrin deployed the Early Apollo Scientific Experiments Package (EASEP), which included instruments for several tests to be left on the lunar surface. The Passive Seismic Experiment contained seismometers to measure moonquakes or effects of meteoroid and other impacts on the Moon. The Laser Ranging Retro-reflector allowed for a precise measurement of the distance between Earth and the Moon, obtained by timing how long it took for a laser beam to travel from Earth to the lunar surface and back.

Another experiment created by Swiss Scientists, collected solar-wind particles that researchers could analyze the composition of solar wind. The team also recorded extensive observations of the lunar surface, photographed the terrain and each other, and gathered 22 kilograms of rock, soil, and dust samples—all in the course of approximately two hours.

The observations and material collected by the Apollo 11 crew led to exciting discoveries. Among the most important findings: analysis of the chemical composition of lunar rocks helped strengthen the theory that the Moon was actually a chip off the young Earth.

Researchers now think that soon after the formation of the solar system, Earth was struck by a Mars-sized object, intimately mixing the two bodies. Some of the resulting vapor and rock later congealed into the single satellite that is our Moon today. This origin story would explain why the Moon doesn’t have a large iron core and is mostly composed of materials found in Earth’s crust, and why the ratios of many isotopes on the Moon’s surface are identical to those found in rocks on Earth. It was a stunning finding,” says Shara.

One of the instruments left on the Moon’s surface—the Laser Ranging Retro-reflector—allowed scientists to collect data for decades after Apollo 11’s return to Earth. Findings include that the Moon is moving farther away from Earth and that the universal force of gravity is stable.

Research based on materials gathered during the Apollo missions continues to this day.

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