... Orbits in Space . ... The ion rocket is another means of providing thrust, more gradually but also more efficiently than a conventional rocket. ... As in the nuclear rocket, the energy which propels the xenon jet comes from a different source; here it is electrical energy from solar cells. ... The XIPS ("zips") ion engine developed by the Hughes corporation was tested in the laboratory and then aboard a Russian spacecraft, launched 6 October 1997; it is the one shown on top of this page. ...

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. ...

Courtesy of NASA's National Space Science Data Center . ... On-orbit dry mass: 1106.00 kg . Venera 4 was launched from a Tyazheliy Sputnik (67-058B) towards the planet Venus with the announced mission of direct atmospheric studies. On October 18, 1967, the spacecraft entered the Venusian atmosphere and released two thermometers, a barameter, a radio altimeter, and atmospheric density gauge, 11 gas analyzers, and two radio transmitters operating in the DM waveband. ... Space History . ...

Cosmic Research, Vol. 42, No. 5, 2004, pp. 435­488. Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 5, 2004, pp. 453­508. Original Russian Text Copyright © 2004 by Veselovsky, Panasyuk, Avdyushin, Bazilevskaya, Belov, Bogachev, Bogod, Bogomolov, Bothmer, Boyarchuk, Vashenyuk, Vlasov, Gnezdilov, Gorgutsa, Grechnev, Denisov, Dmitriev, Dryer, Yermolaev, Eroshenko, Zherebtsov, Zhitnik, Zhukov, Zastenker, Zelenyi, Zeldovich, Ivanov-Kholodnyi, Ignat'ev, Ishkov, Kolomiytsev, Krasheninnikov, Kudela,