Soviet Scientists Describe Sputnik 2

Sputnik 2 was the whole last stage of the rocket, in which all the scientific and measuring instruments were installed. This arrangement materially simplified the problem of determining the satellite's co-ordinates, with the aid of optical instruments.

Our experience with Sputnik 1 showed that observations of the carrier rocket were simpler than of the satellite itself. The carrier rocket was very much brighter than the sputnik.

The combined weight of the apparatus, of the dog and of the batteries on Sputnik 2 was almost exactly half a tonne.

On a special frame in the forward part of the last stage of the rocket were installed an instrument for measuring solar radiations in the ultra-violet and X-ray regions of the spectrum, a spherical container with the radio transmitters and other apparatus, and the hermetically sealed chamber in which the dog was kept. The instruments for studying the cosmic rays were mounted outside the body of the rocket. A special cone protected all these instruments while the rocket was travelling into orbit. When it was in orbit, the cone was discarded.

The radio transmitters and their batteries, the system of heat regulation and the sensitive elements registering the changes in the temperature and other things were put into a spherical container which resembled Sputnik 1 in design. The signals on 15 metres wavelength - the famous "bleep"-lasted an average of about three-tenths of a second, as did the pauses between them. But they changed within certain limits when there were changes in the temperature and pressure in the spherical container. The transmitter on 7.5 metres gave out a continuous signal.

These broadcasts were audible regardless of the state of the ionosphere, enabling a great many radio amateurs in all parts of the world to co-operate in the observations. Reports from these amateurs proved that signals from the sputniks could be reliably received by ordinary amateur receivers at ranges, in some cases, of nearly 10,000 miles.

Laika was put in a hermetically sealed chamber with food and an air-conditioning plant, consisting of a regenerating outfit and a system of heat control, installed. Also installed were instruments to register the dog's pulse, respiration and blood pressure, apparatus to take electro-cardiograms, and sensitive elements to measure the temperature and pressure in the chamber.

The animal's chamber, like the container itself, was made of aluminium alloys, its surface polished and specially treated so as to absorb the right amount of solar radiation.

The heat regulation system installed maintained the temperature within fixed limits, through forced circulation of gas in the chamber.

The equipment also included telemetering apparatus for measuring the temperature, and batteries to provide power for the radio and the various scientific and measuring instruments. The temperature on the outside and inside surfaces of the dog's chamber was measured by means of special apparatus. Temperature gauges were also installed on individual instruments and parts of the sputnik. The radio-telemetering device ensured the transmission of all these readings and those of the instruments installed in the sputnik, to the Earth at fixed intervals.

The full programme of investigations on Sputnik 2 was calculated to work for seven days. The radio transmitters then ceased functioning, and further observations were confined to radar and optical observations of its movements.