By SSubhashini MTech COS 1 st year INTRODUCTION Sputnik 1 was the first artificial Earth satellite It was a 58 cm diameter polished metal sphere with four external radio antennas to broadcast radio pulses ID: 409972
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Slide1
SPUTNIK 1
By,
S.Subhashini
M.Tech
(COS)
1
st
yearSlide2
INTRODUCTION
Sputnik 1 was the first artificial Earth satellite.
It was a 58 cm diameter polished metal sphere, with four external radio antennas to broadcast radio pulses.
The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957 at 19:28:34.
It was visible all around the Earth and its radio pulses were detectable.Slide3Slide4
Cont…
Sputnik
itself provided scientists with valuable information.
The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave information about the ionosphere.
The satellite travelled at about 29,000 kilo-
metres
per hour (18,000 mph), taking 96.2 minutes to complete each orbit.Slide5
Cont..
It transmitted on 20.005 and 40.002 MHz
which were monitored by amateur radio
operators throughout the world.
The signals continued for 22 days until the transmitter batteries ran out on 26 October 1957.
Sputnik
1
burned up on 4 January 1958, as it fell from orbit upon reentering Earth's atmosphere, after travelling about 70 million km and spending 3 months in orbit.Slide6
HISTORY
The story begins in 1952, when the International Council of Scientific Unions decided to establish July 1, 1957, to December 31, 1958, as the International Geophysical Year (IGY) because the scientists knew that the cycles of solar activity would be at a high point then.
In October 1954, the council adopted a resolution calling for artificial satellites to be launched during the IGY to map the Earth's surface. Slide7
Cont..
In July 1955, the White House announced plans to launch an Earth-orbiting satellite for the IGY and solicited proposals from various Government research agencies to undertake development.
In September 1955, the Naval Research Laboratory's Vanguard
proposal was chosen to represent the U.S. during the IGY.
The Sputnik launch changed everything.Slide8
Cont..
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 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.Slide9
Cont…
On November 3, Sputnik II was launched, carrying a much heavier payload, including a dog named
Laika
.
Immediately after the Sputnik I 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 Explorer
project. Slide10
DESIGN
The satellite was a 585-millimetre (23.0 in) diameter sphere, assembled from two hemispheres which were hermetically sealed using
o-rings
and
connected using 36 bolts, and had a mass of 83.6 kilograms.Slide11
Cont…
The hemispheres were 2 mm thick
,
and were covered with a highly polished 1 mm-thick heat
shield
made
of
aluminium
-magnesium-titanium
AMG6T alloy.
("
AMG" is an abbreviation for "
aluminium
-magnesium" and "T" stands for "titanium", the alloy contains 6% of magnesium and 0.2% of
titanium). Slide12
Cont…
The satellite carried two pairs of antennas designed by the Antenna Laboratory of
OKB-1.
Each
antenna was made up of two whip-like parts: 2.4 and 2.9 meters (7.9 and 9.5 ft) in
length,
and
had an almost spherical radiation pattern
,
so that the satellite beeps were transmitted with equal power in all directions, making reception of the transmitted signal independent of the satellite's rotation
.
The whip-like pairs of antennas resembled four long "whiskers" pointing to one side, at equal 35 degree angles with the longitudinal axis of the satellite.
[Slide13
The power supply, with a mass of 51 kg was in the shape of an octagonal nut with the radio transmitter in its hole
.
It consisted of three silver-zinc batteries, developed at the All-Union Research Institute of Current Sources (VNIIT
).
Two of them powered the radio transmitter and one powered the temperature regulation system
.
They were expected to fade out in two weeks, but ended up working for 22 days. Slide14
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