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Launch of Explorer 1 . Click here for a full size version of this image. ... The USSR was first, sending off its first "Sputnik" ("satellite") on October 4, followed by Sputnik II on November 3. ... News conference following the launch of Explorer 1 . ... Unlike the orbits of the Sputniks, that of Explorer 1 was quite elliptical and it rose to an altitude of about 2500 kilometers. ... Explorer 2 failed to orbit, but Explorer 3, launched March 26, was successful, and it did carry a tape recorder. ...

Gaspra . ... On October 29, 1991, Galileo came within 1,600 kilometers (1,000 miles) of Gaspra. ... These two color views of the asteroid Gaspra were produced by combining three images taken through violet, green, and infrared filters by the Galileo spacecraft on October 29, 1991, from a distance of about 16,000 kilometers (10,000 miles). ... The earliest view (upper left) was taken 5 hours, 45 minutes before closest approach when the spacecraft was 164,000 kilometers (102,000 miles) from Gaspra. ...