X-15

Tuesday, January 13, 2009

An experimental rocket plane, built by North American, that set aircraft speed and altitude records, some of which still stand today. First flown on June 8, 1959, the X-15 was used to provide data on thermal heating, control, and stability at extremely high speeds, and on atmospheric reentry. It was made primarily fromtitanium and stainless steel covered with Inconel X nickel, an alloythat can withstand temperatures up to 650°C. To sustain even higher temperatures the X-15 was often covered with a pink ablative material (MA-25S) which could boil away, carrying the heat with it. 

The plane was dropped from a B-52 bomber at an altitude of 13,700 m, and then ignited its Reaction Motors XLR99-RM-2 throttleable liquid propellant (liquid hydrogen and anhydrous ammonia) engine. The rear tail was movable and could be pivoted for control at altitudes where the air was sufficiently thick. At greater (non-atmospheric) heights, control was provided by 12 hydrogen peroxide jets – four in the wingtips and eight in the nose. The plane was piloted following a predetermined flight path, and came down on Rogers dry lakebed using unique landing gear. Just before landing, the lower half of the bottom tail section was jettisoned, and two landing skids deployed, together with a two-wheel conventional landing gear at the nose. 

Three X-15s were built and 199 missions flown, the last in November 1968. During the X-15 program, 13 flights met the US criterion for a spaceflight by passing an altitude of 50 miles (80 km) and the pilots were accordingly awarded astronaut status by the US Air Force. Out of these, two also qualified for the international FAI definition of a spaceflight by exceeding an altitude of 100 km (62.1 miles). The X-15 was the first aircraft to exceed Mach 4, 5, and 6 – records that it broke successively within a nine-month period in 1961 with U.S. Air Force Robert White at the controls. 

Length	16.0 m
Wingspan	6.7 m
Mass, fully fuelled	15,400 kg
Thrust	254,000 N
Maximum speed	7,297 km/h (mach 6.72)
Maximum altitude	107,960 m (67.08 miles)

PSLV (Polar Satellite Launch Vehicle)

Monday, January 12, 2009

PSLV-3C

A four-stage Indian launch vehicle capable of placing a one-ton payload into polar orbit. Its development allows India to launch its own IRS (India Resource Satellite) missions, rather than relying on Russian launch services. The PSLV uses a four-stage core vehicle surrounded by six strap-on boosters of the type developed for the ASLV. At liftoff only two of the strap-ons and the bottom stage of the core vehicle are ignited. The other four boosters are fired at an altitude of 3 km. The core vehicle is unusual in having two solid-propellant stages (1 and 3) and two liquid, hypergolic stages (2 and 4). The PSLV was first launched on Sep. 20, 1993, became operational in March 1996, and has since successfully launched several payloads, including IRS-P4 (Oceansat) and two piggyback satellites, the Korean KITSAT and the German TUBSAT, on May 26,1999. A second successful triple launch for PSLV took place on Oct. 22, 2001, when the German BIRD, the Belgian PROBA, and the Indian TES satellites were placed into their correct orbits by the PSLV-3C mission (see accompanying photo of launch). 

Total mass	294 tonnes
Height	44.4 m
Maximum diameter	2.8 m
Payload to polar orbit	1,000-2,000 kg
Thrust
First stage (+ 6 strap-ons)	8,600,000 N
Second stage	724,000 N
Third stage	324,000 N
Fourth stage	14,800 N

GSLV (geosynchronous Satellite Launch Vehicle)

india’s latest four-stage launch vehicle, capable of placing 2,500-kg Insat-type communications satellites into geostationary transfer orbit. The GSLV improves on the performance of the PSLV (Polar Satellite Launch Vehicle) by the addition of liquid strap-on boosters and a cryogenic upper stage. The solid first and liquid second stages are carried over from the PSLV, while the cryogenic upper stage is being supplied by Russia until India has developed an indigenous version. Carrying a 1.5-ton experimental satellite, the GSLV was launched successfully for the first time on Apr. 18, 2001 – an important first step toward India’s independence in space and competing in the lucrative geosynchronous market. 

Height	49 m
Maximum diameter	2.8 m
Mass at liftoff	402 tons
Payload to GTO (geosynchronous transfer orbit)	2,500 kg

Sputnik missions.

Sunday, January 11, 2009

A series of satellites launched by the Soviet Union at the dawn of the Space Age. “Sputnik” (satellite) was the abbreviated Western name for these spacecraft, known in Russia generically as Iskusstvenniy Sputnik Zemli (Artificial Earth Satellite). 

Sputniks 1, 2, and 3 were launched during the International Geophysical Year, a period lasting from July 1, 1957, to December 31, 1958. Details of these satellites are given below. The spacecraft known in the West as Sputnik 4, 5, 6, 9, and 10 were announced at the time in Russia as Korabl-Sputnik 1, 2, 3, 4, and 5. These were unmanned test launches of the Vostok space capsule which would eventually carry Yuri Gagarin on his historic flight. Sputnik 7 and 8 were Venus probes. 


Sputnik 1 

Sputnik 1

The first spacecraft to be placed in orbit around the Earth. A basket-ball-sized (59-cm) aluminum sphere with four trailing spring-loaded antennae, it carried a small radio beacon that beeped at regular intervals and could verify, by telemetry, exact locations on the Earth’s surface. It decayed three months after launch. 

As a technical achievement, Sputnik caught the world's attention and the American public off-guard. Its size was more impressive than Vanguard's intended 7.7-kg (3.5-pound) payload. In addition, the public feared that the Soviets' ability to launch satellites also translated into the capability to launch ballistic missiles that could carry nuclear weapons from Europe to the U.S. 

Immediately after the Sputnik 1 launch in October, the U.S. Defense Department responded to the political furor by approving funding for another U.S. satellite project. As a simultaneous alternative to Vanguard, Wernher von Braun and his Army Redstone Arsenal team began work on the Explorerproject. 


Sputnik 2 

Sputnik 2

The second artificial satellite and the first to carry a passenger – the dog Laika. Biological data were returned for approximately a week. However, as there was no provision for safe reentry, Laika was put to sleep after a week in space. The satellite itself remained in orbit 162 days. 

Sputnik 2 was a 4-meter high cone-shaped capsule with a base diameter of 2 meters. It contained several compartments for radio transmitters, a telemetry system, a programming unit, a regeneration and temperature control system for the cabin, and scientific instruments. A separate sealed cabin contained the experimental dog Laika. Engineering and biological data were transmitted using the Tral D telemetry system, which would transmit data to Earth for 15 minutes of each orbit. Two spectrophotometers were on board for measuring solar radiation (ultraviolet and X-ray emissions) and cosmic rays. A television camera was mounted in the passenger compartment to observe Laika. 

Sputnik 2 was launched on a Sapwood SS-6 8K71PS launch vehicle (essentially a modified R-7 ICBM similar to that used for Sputnik 1) into a 212 × 1660 km orbit with a period of 103.7 minutes. After reaching orbit the nose cone was jettisoned successfully but the Blok A core did not separate as planned. This inhibited the operation of the thermal control system. Additionally some of the thermal insulation tore loose so the interior temperatures reached 40°C. It is believed Laika survived for only about two days instead of the planned ten because of the heat. The orbit of Sputnik 2 decayed and it reentered Earth's atmosphere on April 14, 1958 after 162 days in orbit. 


Sputnik 3 

Sputnik 3

The last in the series, though prior to a decision to be more cautious in the launch schedule it may have been intended as the first. Sputnik 3 was an automatic scientific laboratory spacecraft. It was conically-shaped and was 3.57 meters long. The scientific instrumentation (twelve instruments) provided data on pressure and composition of the upper atmosphere, concentration of charged particles, photons in cosmic rays, heavy nuclei in cosmic rays, magnetic and electrostatic fields, and meteoric particles. The outer radiation belts of the Earth were detected during the flight. The spacecraft remained in orbit until April 6, 1960. 

Spacecraft	Launch date	Orbit	Mass (kg)
Sputnik 1	Oct. 4, 1957	228 × 947 km	83.6
Sputnik 2	Nov. 3, 1957	225 × 1,671 km	508
Sputnik 3	May 15, 1958	230 × 1,880 km	1,327