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Time Machine (1957): Sputnik By Scientific American, adapted by Newsela staff on 03.30.16 Word Count 763 A replica of Sputnik 1 at the U.S. National Air and Space Museum Newsela Editor's Note: This article originally appeared in the November 1957 issue of Scientific American. The Soviet Union made history on Oct. 4, 1957. A rocket was launched into space. It sent a satellite called Sputnik into orbit around the Earth. Due to gravity, most rockets that go up eventually fall back down to Earth. If a rocket is high enough and is traveling fast enough, though, gravity can send it on a path around the planet (an orbit). Once in orbit, it can continue traveling for a long time thanks to gravity. Things in orbit are called satellites. Orbiting The Earth Sputnik means "fellow traveler" in Russian. It is the first man-made satellite in human history. It is orbiting, or circling, Earth like the moon, which is a natural satellite. The launch has caught the world by surprise. Russia did not tell anyone about Sputnik in advance. Many details are still uncertain. This is what is known so far: The launch was announced in the late afternoon on Oct. 4. Russia did not say where the launch took place. Some have guessed that it happened near the Caspian Sea. Three-Stage Rocket Launch Sputnik was sent into space in a three-stage rocket. Three-stage rockets are like three rockets stacked on top of each other. Each has its own engine and fuel supply. The bottom rocket launches from the ground, carrying the other two with it. When its fuel is used up, it drops off, and the next rocket kicks in, and so on. In this way, three-stage rockets can shed weight as they gain speed. The Russian announcement said the rocket's total power equaled that of the world's largest hydroelectric station, which harnesses power from the flow of a river. Rocket experts in other countries estimated the take-off weight to be somewhere between 150,000 and 300,000 pounds. Sputnik Looks Like A Metal Ball Sputnik had the appearance of a metal ball with four antennae. It was about 23 inches wide and weighed about 184 pounds. It carried two radio transmitters. Batteries for the transmitters took up most of the space inside the satellite. Whether it carried other instruments was not clear. Soviet scientists said the satellite was recording temperature. U.S. scientists believed it was using radio to send information down to Earth. The satellite did not orbit the Earth on the same path as the moon. Instead, it was tilted at an angle of 65 degrees. As a result, the satellite did not just travel east to west. It also traveled north to south, making its way diagonally around the globe. The satellite circled Earth in 96 minutes. It traveled about 18,000 miles every hour. At times, it was as many as 600 miles above the Earth. Watching Sputnik From Earth In Russia, observers could keep their eyes on the satellite from the beginning. It passed over the country at dawn and twilight. At those times of day, it could be seen more easily. In the United States, people could not see the satellite at first. They were able to follow its radio signals, though. Radio information, along with a few sightings in Australia, Alaska and finally in the United States, allowed U.S. scientists to figure out how the satellite was orbiting. Sputnik is expected to provide valuable information about the Earth and space. It will measure the air thickness of the outer atmosphere and will tell us more about the shape of Earth. It will also possibly lead to discoveries about the temperature at the borders of space. Long Time Coming Russian scientists said they hoped to launch larger Sputniks soon. The U.S. planned to fire a small satellite in December and a larger one by March or April. Soon, a whole flock of satellites may be flying around the Earth. Scientists have dreamed of sending satellites into space for many years. Hermann Oberth is one of the first rocket scientists. He was the first to work on satellites in a serious way. In 1923, he proposed a manned space station from which scientists could observe space. Developing Rocket Technology Sending satellites into orbit became possible after the technological advances of World War II. Radio technology allowed information to be sent over vast distances, making it possible to send up small satellites to collect information in space and then send it back to Earth. A number of experts started working on satellite projects in the years following the war. At that point, Russia had already been working with rockets for many years. Now, with the success of Sputnik, they have made history. Quiz 1 Which two answer choices are MAIN ideas of the article? 1. The United States wanted to launch a satellite like Sputnik. 2. Sputnik was the first man-made satellite. 3. Using three stages made Sputnik's rocket lighter. 4. Radios are important for Sputnik's success. 2 3 4 (A) 1 and 2 (B) 2 and 3 (C) 3 and 4 (D) 1 and 4 Which of these sentences supports a MAIN idea from the article? (A) Due to gravity, most rockets that go up eventually fall back down to Earth. (B) Three-stage rockets are like three rockets stacked on top of each other (C) U.S. scientists believed it was using radio to send information down to Earth. (D) Hermann Oberth is one of the first rocket scientists. Which of the following BEST describes Sputnik's path? (A) Sputnik traveled from the United States to Russia. (B) Sputnik traveled to the moon. (C) Sputnik traveled all around the globe. (D) Sputnik traveled to the Caspian Sea. Which answer choice BEST describes what the article says about Sputnik's place in the history of space travel? (A) an important development built on earlier work (B) a creative reuse of inventions already used in World War II (C) a completely different invention from anything people had made before (D) a disappointing failure following the accomplishments of earlier scientists