RaQua Δημοσιεύτηκε Αύγουστος 27, 2002 Δημοσιεύτηκε Αύγουστος 27, 2002 CONTOUR: MISSING IN ACTION At 4:49 a.m. Eastern Daylight Time on August 15th, the Contour spacecraftwas to fire its engine, leave its Earth orbit, and head off intointerplanetary space. When the burn took place, the craft was 225kilometers (140 miles) above the Indian Ocean, in a blind spot fromcommunications. Deep-Space Network tracking stations in either Goldstone,California, or Canberra, Australia, were supposed to reestablish contactwith the spacecraft 46 minutes later. But all attempts to reach the craftwent unanswered.... NASA has turned to amateur astronomers for help locating the craft. Sinceits launch on July 3rd, many advanced amateurs with the capability toobserve the faintest asteroids have also watched and imaged Contourorbiting Earth. Even if Contour's burn was successful, it should still bearound 18th magnitude -- within the capabilities of amateurs with largetelescopes and CCD cameras.... http://SkyandTelescope.com/news/current/article_700_1.asp CONTOUR'S FATE LOOKS "BLEAK" Although efforts to reestablish contact with the Contour spacecraftcontinue, mission managers now suspect that the craft was destroyed duringa rocket firing on August 15th. Convincing evidence came from imagesacquired by the Spacewatch telescope about 20 hours afterward, showing twoobjects separated in the sky by about 460 kilometers and located some460,000 km from Earth.... Mission mananger Robert W. Farquhar and his team received the Spacewatchimage in response to a call to professional and amateur astronomers tohelp locate the spacecraft. The image shows a pair of 18th-magnitudeobjects, one approximately three times brighter than the other. Accordingto David W. Dunham, head of the mission-design team, the objects were thenwithin 0.6 degrees of where Contour would have been if on its correctinterplanetary trajectory, and their positions suggest that Contour'ssolid-fuel STAR-30 rocket motor provided about 3 percent less total thrustthan expected. Dunham estimates that "Contour A" and "Contour B" aremoving apart at roughly 6 meters per second (14 miles per hour). It is notyet clear what the two pieces might be. "The spacecraft was built aroundthe STAR motor," Dunham notes, "and they weren't supposed to separate...." http://SkyandTelescope.com/news/current/article_712_1.asp NASA appoints CONTOUR mission investigation teamNASA Administrator Sean O'Keefe has announced that Chief Engineer Theron M. Bradley Jr. will lead a team to investigate the apparent loss of the CONTOUR mission space probe. The investigation team will independently examine all aspects of the CONTOUR mission, which has been out of contact with controllers since a scheduled engine firing Aug. 15. http://www.spaceflightnow.com/news/n0208/26contour/
RaQua Δημοσιεύτηκε Σεπτέμβριος 5, 2002 Συγγραφέας Δημοσιεύτηκε Σεπτέμβριος 5, 2002 Contour Watch Winds Down Spaceflight engineers have little hope for recovering the Comet NucleusTour (Contour) spacecraft, though they will continue to listenperiodically for its signal through December. The comet-bound craft waslast heard from on August 15th, just before a solid-fuel rocket was topropel it from its temporary Earth orbit into interplanetary space.Telescopic images later showed two objects leaving Earth along (but alittle behind) the predicted trajectory. "Obviously, we had a bigproblem," comments Robert Farquhar, the Contour mission manager at JohnsHopkins University's Applied Physics Laboratory. Although the cause of themission-ending malfunction may never be determined with certainty, for nowthe APL team is presuming either that the Star 30 motor ruptured justbefore the end of its 50-second-long firing, or that heat from the rockettriggered the failure of some other component (such as the tanks ofhydrazine fuel used for smaller maneuvers). The Contour team hopes to convince NASA to build a replacement craft,which might be launched as soon as 2006. However, this effort wouldoverlap -- and compete for scarce funds - with the proposed New Horizonsmission to Pluto, which APL is also building. Meanwhile, NASAadministrator Sean O'Keefe has tasked Theron Bradley Jr., the spaceagency's chief engineer, to lead the investigation into Contour's loss.Bradley is expected to report his panel's findings in six to eight weeks. Sky&Telescope
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