After the success of Sputnik 1 in October 1957, Nikita Khrushchev, the Soviet leader, wanted a spacecraft launched on 7 November 1957, the 40th anniversary of the October Revolution. Construction had already started on a more sophisticated satellite, but it would not be ready until December; this satellite would later become Sputnik 3. Meeting the November deadline meant building a new craft. Khrushchev specifically wanted his engineers to deliver a "space spectacular", a mission that would repeat the triumph of Sputnik 1, stunning the world with Soviet prowess. Planners settled on an orbital flight with a dog. Soviet rocket engineers had long intended a canine orbit before attempting human spaceflight; since 1951, they had lofted twelve dogs into sub-orbital space on ballistic flights, working gradually toward an orbital mission set for some time in 1958. To satisfy Khrushchev's demands, they expedited the orbital canine flight for the November launch. According to Russian sources, the official decision to launch Sputnik 2 was made on 10 or 12 October, leaving less than four weeks to design and build the spacecraft. Sputnik 2, therefore, was something of a rush job, with most elements of the spacecraft being constructed from rough sketches. Aside from the primary mission of sending a living passenger into space, Sputnik 2 also contained instrumentation for measuring solar irradiance and cosmic rays. The craft was equipped with a life-support system consisting of an oxygen generator and devices to avoid oxygen poisoning and to absorb carbon dioxide. A fan, designed to activate whenever the cabin temperature exceeded 15 °C (59 °F), was added to keep the dog cool. Enough food (in a gelatinous form) was provided for a seven-day flight, and the dog was fitted with a bag to collect waste. A harness was designed to be fitted to the dog, and there were chains to restrict her movements to standing, sitting, or lying down; there was no room to turn around in the cabin. An electrocardiogram monitored heart rate and further instrumentation tracked respiration rate, maximum arterial pressure, and the dog's movements.