Never in the history of exploration has there been an undertaking quite like Apollo. ... Few of the half million ever had a chance to travel in space and fewer still walked on the Moon; but most were deeply dedicated and, for them, working on Apollo was much more than a job. ... Apollo was a start. ... By the time of the last three missions, crews were spending three days on the Moon and, out of each twenty-four hours, were staying outside and working hard for six to seven hours at a time. ...

This groups includes about 200 communication satellites ("comsats") scattered in synchronous orbits above the Earth's equator. ... 6 Earth radii (42,000 km or 26,000 miles), these satellite make one orbit per day, and therefore as the Earth turns, they always stay above the same ground station. ... Still another application is the 24-satellite network of the "Global Positioning System" (GPS), in circular orbits at distances of about 4.1 Earth radii (26,000 km or 16,000 miles). ...

. Click icons to make large pictures. The annual distribution of the satellite locations in the geophysical regions labeled by the regions marks. The dates are shown along the X axis, . The time on the orbit counted from ascending node of the each turn is shown along the Y axis. Orbit in the Solar ecliptic coordinate system . Dr. Victoria Prokhorenko . Dated 04 August 98 

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,