Celestial Events 



Lost but Not Forgotten 



by Gail S. Cleere 



As the new year begins, Mars is liidden 

 in the solar glare, along with Mercury, 

 Venus, Neptune, and Uranus. The Mars 

 Obseiyer is hiding, too. All contact with 

 the spacecraft was lost last August 21, 

 after it had journeyed 450 million miles to 

 reach the red planet. For several weeks, 

 technicians tried everything they could 

 think of to reestablish contact, but no re- 

 sponse was picked up on NASA's Deep 

 Space Network of antennas. Without con- 

 tact, scientists have no way of telling 

 where the spacecraft is or even if it still ex- 

 ists. It may be uselessly orbiting Mars, or 

 it may have sped past its destination on a 

 path that will eventually take it out of the 

 solar system. 



The silence began just as flight con- 

 trollers at California's Jet Propulsion Lab- 

 oratory sent signals to pressurize the 

 spacecraft's propellant tanks in prepara- 

 tion for maneuvers that would place it in 

 orbit around Mars. Pressurizing the tanks 

 required opening valves, which are oper- 

 ated by firing small explosive charges. The 

 resultant jolts may have caused the space- 

 craft's main and backup clocks to fail si- 

 multaneously when faulty transistors or 

 wiring welds were jarred, crippling the 

 craft's central computers and communica- 

 tions systems. Transistors of the type used 

 in the Mars Observer have failed on other 

 spacecraft, such as the NOAA-1 weather 

 satellite. A NASA committee has been set 

 up to investigate the failure and to insure 

 that no other spacecraft contains the sus- 

 pect transistors. 



The loss of the Mars Observer has been 

 a major setback for planetary scientists. 

 The first spacecraft to visit Mars since the 

 Viking landers touched down in 1976, the 

 Mars Observer was to have mapped the 

 planet from an altitude of 250 miles for 



one Martian year (687 Earth days). Its in- 

 struments were designed to provide a 

 wealth of data on the red planet's topogra- 

 phy, atmosphere, climate, and geology. 

 More than a hundred scientists were 

 poised to begin analyzing the flow of data 

 beamed to Earth — more data on the red 

 planet than had been obtained from all the 

 previous Mars missions combined. 



Some of the infoimation was crucial to 

 planning future Mars missions that are al- 

 ready scheduled. Another NASA space- 

 craft, named Pathfinder, is due to land on 

 Mars in July 1997 to carry out the Mars 

 Environmental Survey Mission. Path- 

 finder will include a lander and a rover 

 carrying instruments and cameras for 

 gathering information from the planet's 

 surface. Scientists were hoping for more 

 detailed images of the Martian terrain 

 from Mars Observer to help them select 

 Pathfinder landing sites. 



Last September, in the wake of the 

 Mars Observer disaster, Daniel Goldin, 

 NASA's chief administrator, challenged 

 his agency to find a way to build and 

 launch another Mars spacecraft by Octo- 

 ber 1994, when the earth and Mars come 

 into proper alignment (which happens 

 only once every twenty-six months). A 

 team of scientists was quickly put together 

 to review the options. Thek recommenda- 

 tion was to use spare Mars Obser\>er elec- 

 tronic and instrument components, which 

 were built as test models and backups and 

 are now stored in New Jersey, and assem- 

 ble them on a lightweight military satellite 

 frame. The craft could have been carried 

 aloft by the space shuttle and boosted out 

 of the earth's orbit by rocket, or it could 

 have been launched on a foreign rocket. 

 Despite NASA's efforts, however, a new 

 Mai'S spacecraft will not be ready on time. 



The Russians plan to take advantage of 

 next October's window of opportunity to 

 launch landers that will reach Mars in late 

 1995. This mission will feature not only 

 landers but also rovers that wiU traverse 

 the terrain analyzing samples, as well as a 

 balloon that will drift along dragging sen- 

 sors across the Martian surface. NASA 

 will have to wait until 1996 to launch a 

 mission to Mars. 



The Planets in January 



Mercury is close to the sun at the be- 

 ginning of the month. During the final 

 week of January, however. Mercury 

 moves far enough away to be spotted on 

 the western horizon just after sundown. It 

 will make a close approach to Saturn at the 

 end of the month. 



Venus reaches superior conjunction 

 wifli the sun on the 16th. It is then behind 

 the sun. 



Mars is a morning object, but much too 

 close to the sun to be seen. 



Jupiter rises a couple of hours after 

 midnight and shines brightly in the south- 

 em sky by dawn. The planet, now residing 

 in the constellation Libra, continues its ret- 

 rograde (western) motion across the sky 

 and approaches Zubenelgenubi, the third- 

 magnitude star that marks the right claw of 

 Scorpius. On the morning of the 6th, the 

 waning crescent moon stands weU below 

 and to the right (west) of Jupiter, and on 

 the 7th it will be well below and to the left 

 (east) of Jupiter. 



Saturn is in Aquarius this month, rising 

 in midmoming to the east of the sun. It sets 

 in the west a few hours after sunset. This 

 gives us a chance for one last look at the 

 ringed planet before the sun's glare over- 

 powers it. On the evening of the 14th, Sat- 

 urn will be the bright, yellowish white 



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