January 30, 2005
A Marvelous Sense of Theater
In this multipart series on the twin Viking landers that pioneered surface imagery and exploration on Mars, the events leading to the first and tense rocket-powered landing of Viking I are described.
Astrobiology Magazine -- The NASA History Office has compiled a definitive account of the early robotic exploration of the martian surface. The account's first-person immediacy highlights particularly the pair of Viking landers that lasted for up to six years on the surface. AM excerpts a series of historical reviews of significant events to this search for life on the red planet.For many members of the Viking flight team, the early morning hours of 20 July 1976 were the culmination of 8 years of intense activity. Several of the scientists had more than 15 years invested in preparations for the investigations that would begin once Viking safely landed on the surface of Mars.
The focus of everyone's attention on this day was the Viking I spacecraft in orbit around Mars. Across 348 million kilometers, the team maintained contact with the 3250-kilogram craft from the Jet Propulsion Laboratory (JPL) in Pasadena, California. JPL this night stood jewellike, its brightly lit buiIdings contrasting sharply with the darkened silhouette of the San Gabriel Mountains.
Outside the Theodore von Karman Auditorium, converted into a press center for the mission, mobile television vans were being readied to broadcast the news of Viking's success or failure.
While reporters prepared stories and visitors strolled over the grounds, members of the flight team could be seen on the closed-circuit television monitors as they sat in the half-light of the control room. Elsewhere, hundreds of engineers, scientists, technicians, and support crews were at work or waiting to go to work.
At 1:52 a.m., PDT, the audio circuit on the JPL television came to life, and George Sands, associate project scientist and for the moment the "Voice of Viking," announced: "We have separation.... We have engineering data indicating separation....Separation is being confirmed all along the line."
Eighteen minutes 18 seconds earlier, the time it took the confirming radio signal to travel from Mars to Earth, the lander had separated from the orbiter.
By 2 a.m., the noise that had been building up at the press center and in the visitor areas diminished. Mission control, a small, glass-walled room with men seated around a circular console watching data displayed on television screens, was being projected on monitors around the lab. "
Beyond the controllers' desks and the consoles, through the glass walls of his office.... [was] Jim Martin, a big man in a short-sleeved blue shirt." James Slattin Martin, Jr., had the bearing and appearance of a military man. His closely cropped iron gray hair added to the image and encouraged nicknames like the "Paratroop Colonel" and the "Prussian General."
Many members of the Viking team would attest publicly that he had run a tight project, but even those who had cursed him under their breath over the years had to admit that the incredible performance of the spacecraft during its 11-month cruise toward Mars and the normal postseparation checkout of the lander indicated that all the discipline and hard work Martin had put them through had been worth it.
With a billion dollars invested in two spacecraft, someone had to have a firm grip. As the lander in its protective aeroshell fell freely toward the surface thousands of kilometers below it, Jim Martin listened to the controllers reporting tersely and calmly on the latest electronic news.
At 3 a.m., Albert R. Hibbs, a senior advanced missions planner at JPL, relieved George Sands in the commentator's booth. Hibbs, a veteran "voice" of many earlier unmanned spacecraft directed from Pasadena, had what one observer called "marvelous sense of theater."
Smiling, Hibbs noted that the deorbit burn of the lander's eight small rocket motors had gone smoothly and the spacecraft had proper velocity. Impishly, he noted that it was also going the right direction.
(to be continued)
Based on NASA's "On Mars: Exploration of the Red Planet. 1958-1978", NASA SP-4212 History Office.
NASA's Viking Mission to Mars was composed of two spacecraft, Viking 1 and Viking 2, each consisting of an orbiter and a lander. The primary mission objectives were to obtain high resolution images of the Martian surface, characterize the structure and composition of the atmosphere and surface, and search for evidence of life. Viking 1 was launched on August 20, 1975 and arrived at Mars on June 19, 1976. On July 20, 1976 the Viking 1 Lander separated from the Orbiter and touched down at Chryse Planitia, just north of the equator.
Viking 2 was launched September 9, 1975 and entered Mars orbit on August 7, 1976. The Viking 2 Lander touched down at Utopia Planitia much further north and on nearly the opposite side of Mars on September 3, 1976. The Viking Landers transmitted images of the surface, took surface samples and analyzed them for composition and signs of life, studied atmospheric composition and meteorology, and deployed seismometers.
The Viking 2 Lander ended communications on April 11, 1980, and the Viking 1 Lander on November 13, 1982, after transmitting over 1400 images of the two sites.
On the Net:
Life on Mars: Viking and the Biology Experiments (Wayne RESA)