Don't do this... 'n' Don't do that

NASA's Space Shuttle, officially called the Space Transportation System (STS), is the spacecraft currently used by the United States government for its human spaceflight missions. At launch, it consists of a rust-colored external tank (ET), two white, slender Solid Rocket Boosters (SRBs), and the orbiter, a winged spaceplane which is the space shuttle in the narrowest sense.

The orbiter carries astronauts and payload such as satellites or space station parts into low earth orbit, into the Earth's upper atmosphere or thermosphere.^[1] Usually, five to seven crew members ride in the orbiter. The payload capacity is 22,700 kg (50,000 lb). When the orbiter's mission is complete it fires its Orbital Maneuvering System (OMS) thrusters to drop out of orbit and re-enters the lower atmosphere.^[1] During the descent and landing, the shuttle orbiter acts as a glider, and makes a completely unpowered ("deadstick") landing.

Description

The shuttle is the first orbital spacecraft designed for partial reusability. It carries payloads to low Earth orbit, provides crew rotation for the International Space Station (ISS), and performs servicing missions. The orbiter can also recover satellites and other payloads from orbit and return them to Earth, but this capacity has not been used often. However, it has been used to return large payloads from the ISS to Earth, as the Russian Soyuz spacecraft has limited capacity for return payloads. Each Shuttle was designed for a projected lifespan of 100 launches or 10 years operational life. The man responsible for the design of the STS was Maxime Faget, who had also overseen the Mercury, Gemini and Apollo spacecraft designs. The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned commercial and classified satellites, and have the cross-range recovery range to meet classified USAF missions requirement for a one-around abort for a polar launch. Factors involved in opting for 'reusable' solid rockets and an expendable fuel tank included the desire of the Pentagon to obtain a high-capacity payload vehicle for satellite deployment, and the desire of the Nixon administration to reduce the costs of space exploration by developing a spacecraft with reusable components.

Six air-worthy shuttles have been built; the first orbiter, Enterprise, was not built for space flight, and was used only for testing purposes. Five space-worthy orbiters were built: Columbia, Challenger, Discovery, Atlantis, and Endeavour. Challenger disintegrated 73 seconds after launch in 1986, and Endeavour was built as a replacement. Columbia broke apart during re-entry in 2003.

Each Space Shuttle is a partially reusable launch system that is composed of three main assemblies: the reusable Orbiter Vehicle (OV), the expendable external tank (ET), and the two partially-reusable solid rocket boosters (SRBs). The tank and boosters are jettisoned during ascent; only the orbiter goes into orbit. The vehicle is launched vertically like a conventional rocket, and the orbiter glides to a horizontal landing, after which it is refurbished for reuse.

Roger A. Pielke, Jr. has estimated that the Space Shuttle program has cost about US$170 billion (2008 dollars) through early 2008. This works out to an average cost per flight of about US$1.5 billion.^[2]

At times, the orbiter itself is referred to as the space shuttle. Technically, this is a misnomer, as the actual "Space Transportation System" (space shuttle) is the combination of the orbiter, the external tank (ET), and the two partially-reusable solid rocket boosters. Combined, these are referred to as the "Stack".

Technical Data

Orbiter specifications^[13] (for Endeavour, OV-105)

• Length: 37.24 m (122.17 ft)
• Wingspan: 23.79 m (78.06 ft)
• Height: 58.58 ft (17.86 m)
• Empty weight: 68,585 kg (151,205 lb)
• Gross liftoff weight: 109,000 kg (240,000 lb)
• Maximum landing weight: 104,000 kg (230,000 lb)
• Main engines: Three Rocketdyne Block IIA SSMEs, each with a sea level thrust of 1.75 meganewtons (MN) (393,800 pounds-force (lbf))
• Maximum payload: 25,061 kilograms (55,250 lb)
• Payload bay dimensions: 4.6 m (15 ft) by 18 m (59 ft)
• Operational altitude: 100 to 520 nmi (185 to 960 km)
• Speed: 7,743 m/s (27,875 km/h, 25,404 ft/s, 17,321 mi/h)
• Crossrange: 2,009 km (1,085 nmi)
• Crew: Varies. The earliest shuttle flights had the minimum crew of two; many later missions a crew of five. Today, typically seven people fly (commander, pilot, several mission specialists, and rarely a flight engineer). On two occasions, eight astronauts have flown (STS-61-A, STS-71). Eleven people could be accommodated in an emergency mission (see STS-3xx).

External tank specifications (for SLWT)

• Length: 46.9 m (153.8 ft)
• Diameter: 8.4 m (27.6 ft)
• Propellant volume: 2,025 m³ (535,000 US gal)
• Empty weight: 26,535 kg (58,500 lb)
• Gross liftoff weight: 756,000 kg (1,667,000 lb)

Solid Rocket Booster specifications

• Length: 45.6 m (149.6 ft)
• Diameter: 3.7 m (12.14 ft)
• Empty weight (per booster): 63,272 kg (139,491 lb)
• Gross liftoff weight (per booster): 590,000 kg (1.3 million lb)
• Thrust (sea level, liftoff): 12.5 MN (2.8 million lbf)

System Stack specifications

• Height: 56 m (183.7 ft)
• Gross liftoff weight: 2 million kg (4.5 million lb)
• Total liftoff thrust: 30.16 MN (6.781 million lbf)

Jika malam hari tiba, terutama di sekitar lampu penerang, biasanya banyak berdatangan cicak atau tokek. Binatang melata ini bisa berjalan lincah tanpa takut jatuh dari dinding atau atap rumah. Kakinya seakan lengket pada dinding. Karena itulah binatang melata ini bisa dengan mudah memangsa serangga yang ikut mampir di sekitar lampu. Kadangkala kita berpikir, “kok cicak dan tokek itu tidak jatuh dari dinding atau atap rumah ya ?”. Ada yang mengira bahwa pada kaki cicak terkandung zat perekat sehingga bisa menahan tubuhnya agar tidak terjatuh ke lantai. Tapi pendapat ini jelas dibantah, sebab pada bekas langkah kaki cicak tidak ditemukan zat-zat seperti itu. Sungguh aneh dan hal ini terus menjadi misteri.

Beberapa waktu yang lalu, rahasia alam ini berhasil diungkapkan oleh kelompok peneliti dari universitas California Barkeley. Dari berbagai data yang berhasil terkumpul, mereka meyakini bahwa kekuatan perekat pada telapak kaki cicak ditimbulkan oleh tenaga van der Waals.

Mereka menemukan adanya sekitar 500 ribu bulu halus yang kuat pada telapak kaki cicak. Bulu halus ini mengandung senyawa keratin yang juga terkandung pada rambut manusia. Bulu halus pada telapak kaki cicak ini panjangnya bervariasi, antara 30 sampai 130 mikrometer. Tebalnya pun hanya sepersepuluh tebal rambut manusia. Yang lebih menakjubkan lagi, ternyata ujung bulu halus ini masih terbagi lagi menjadi beberapa bagian yang berbentuk mirip dengan sendok teh.

Kekuatan pelekat yang ditimbulkan oleh daya van der Waals bulu halus ini sangat menakjubkan. Satu bulu halus tadi bisa memiliki kekuatan pelekat sampai 10 atm. Mereka mengukurnya langsung dengan menggunakan sebuah alat bernama atomic force microscope (AFM).