Home Table of Contents What's New Image Index Copyright ScienceViews Search

On Mars: Exploration of the Red Planet. 1958-1978
 
 
FIRST PHASE OF VIKING ORBITER PLANNING
 
 
 
[167] Working within this milieu that stressed building on proved technological concepts, the engineers at Langley and JPL also made maximum use of earlier subsystems for the Viking orbiter. First considerations for a design of a Titan-Mars 1973 orbiter mission had begun even before the 1971 Mariner or 1973 Viking flights had been approved. A Titan-Mars orbiter....
 
 
 
Assembly of Mariner 9 at Jet Propulsion Laboratory. The spacecraft's solar panels are spread.
 
 
[168]....design team led by Casper F. Mohl was established at JPL in August 1968. with Dalton D. Webb, Jr., as the group's Langley representative.
 
Casey Mohl was an advanced mission planner at the California lab. He had worked on Explorer 1 and on several lander capsule studies for Ranger. During the Voyager effort, he had participated in the capsule systems advanced development activities, part of JPL's hard-lander studies. When the laboratory began to work with Langley's Advanced Spacecraft Project Office on the 1973 mission, JPL Director Pickering assigned Mohl and a group of his colleagues to the "pre-project effort," and the men began to study the diameters, and weights of possible 1973 orbiters. 17 As they worked, they discovered that every time the Langley people "did something to the lander, it ricocheted back to the orbiter, especially into the [propellant] tank sizing."
 
Orbiter size was limited by the diameter of the Centaur launch shroud, which was 3.65 meters. Weights considered during the fall of 1968 ranged from 454 to 680 kilograms for the orbiter and 590 to 907 kilograms for the lander. At this early stage in the planning, many suggestions for the mission design were made, including one by JPL engineer Robert A. Neilson that the 1973 flight be made using a 1971 orbiter without scientific instruments or scan platform. Later, of course, such an idea would be unthinkable, but during the mission definition period one of the alternatives called for using the orbiter simply as a bus to deliver the lander to Mars. 18 The two JPL orbiter proposals presented to the Langley Research Center Advanced Space Projects Office on 9 and 30 October did not include any scientific instruments for the orbiting vehicle, as the JPL planners wanted to consider initially only the minimum number of modifications in the 1971 orbiter, just then beginning to take shape on the drawing board. 19
 
By mid-November 1968, the JPL advanced planners had gone about as far as they could with the design of an orbiter for 1973 without approval of the project by Congress and the president. But at a 5 December meeting, a very pleased Casper Mohl told the "out-of-orbit" design team that the Titan-Mars 73 project had received the approval of the Bureau of the Budget; they could proceed with the development of an orbiter design while Langley worked on the lander. Although the orbiter science payload would not be defined until the Mariner 69 results were known, John Naugle said that, for planning purposes, the candidate experiment hardware in descending order of priority would include: Mariner 71-style television camera, high-resolution infrared radiometer, infrared interferometer spectrometer, near-infrared mapper, x-ray spectrometer, three-channel ultraviolet photometer, and polarimeter. Projected weights for the orbiter at launch were 1880 to 2130 kilograms, and the lander would weigh between 680 and 920 kilograms, with approximately 70 kilograms allocated for orbital science instruments. 20
 
[169] Between mid-November 1968 and mid-February 1969, JPL worked on a "baseline orbiter conceptual design" for the Viking mission, while the project office at Langley concentrated on staffing key management positions. In Pasadena 13-l4 February, JPL hosted a review of its conceptual design for the orbiter. The Viking spacecraft (orbiter and lander) was to be launched by a Titan IIID-Improved Centaur, which could lift a combined weight of 3330 kilograms (2513 kilograms for the orbiter and 817 kilograms for the lander). The orbiter and lander would have a minimum life of 90 days after touchdown on Mars. The lander would have communications links directly with Earth stations and through the orbiter, which would serve as a relay satellite.
 
A key element of the February presentation was the technology that would be borrowed from Mariner 71. For electricity, the Viking orbiter power subsystem was essentially the same as for Mariner 71, providing lander power during transit and early orbital cruise periods. For 50 days of solar occultation during the 1973 mission, the spacecraft would be without the benefit of the sun's energy for one-half to three and one-half hours in each orbit. The increased distance of Mars from the sun during the Viking mission and the revised science instruments also led to some new requirements for the power system. New solar panels were designed, along with a new battery and battery charger. Minor changes were made in the power distribution circuitry, but the core of the entire system was borrowed from Mariner design. 21
 
Industry representatives would later write to James S. Martin, Viking project manager at Langley, complaining about JPL's conservative orbiter design. L. I. Mirowitz, director of planetary systems at McDonnell Douglas Astronautics Company in St. Louis, believed that "spacecraft performance could be judiciously improved by considering some newer components; for example, the [central computer and sequencer] has a 512 word sequencer weighing [12.5 kilograms], the current state of the art permits use of a lander computer and sequencer that has a 6000 word capacity and weighs [11.3 kilograms]." 22 A. J. Kullas at the Denver Division of Martin Marietta Corporation also believed that weights could be reduced and performance improved by being less conservative than JPL had been in its engineering. In one instance, Kullas suggested that newer kinds of electrical cabling would permit a weight reduction from about 49 kilograms to 39, a saving of 20 percent. 23 While there was no doubt that the JPL baseline orbiter design could be improved, the conservative engineering was not unreasonable in an era of stringent budgets and equally tight schedules. Building on previously proved hardware concepts helped to ensure space- craft reliability within the budget and on time. The specialists at JPL evaluated alterations to the basic design, and the orbiter did change over time, but conservative engineering prevailed. 24
 
 
[170] Organizing Orbiter Management
 
 
Early in April 1969, a formal Viking Orbiter Office was set up at JPL to replace the ad hoc arrangements that had existed since the official initiation of the 1973 landing project. Pickering announced the establishment of the management office on the 17th and named Henry W. Norris Viking orbiter manager. Casey Mohl's team went out of business at about the same time, and some of the members of that group joined Norris. A native Californian and graduate of UCLA, Norris had worked in aviation and space activities at General Precision Inc. before joining JPL at the age of 41 in 1963. During the Mariner Mars 69 mission, Norris served as spacecraft systems manager. Kermit S. Watkins, deputy to Norris, came to the Viking project from the JPL Office of Flight Projects, having also been assistant program manager for the Surveyor lunar landers. 25
 
Other key personnel members appointed to the orbiter team by Director Pickering included Allen E. Wolfe, spacecraft systems manager, and Conway W. Snyder, Viking orbiter scientist. Wolfe had been spacecraft systems manager for Project Ranger and for the Mariner 5 Venus mission in 1967. A nuclear physicist by education, Snyder had worked at the California Institute of Technology on Navy rocket research projects during World War II. He joined the JPL physics staff in 1956 and was principal investigator on three space experiments that studied the solar wind, becoming Mariner 5 project scientist. 26 While Norris, Watkins, Wolfe, and Snyder were essential. highly visible members of the orbiter staff at JPL, they represented only the top of a large pyramid. When the orbiter management held its first weekly staff meeting on 1 April 1969, Norris told the participants that their sessions were not designed to resolve problems, but to discuss them "in sufficient depth to understand and identify items for separate action. " 27
 
One of the immediate concerns of the project managers was the growing cost of the orbiter as projected in periodic estimates. Early in February, Charles W. Cole, manager of the Advanced Planetary Missions Technology Office at JPL, informed Martin that the hardware for the total orbiter system (two flight craft, spares, and test models) would cost nearly $147 million, while the total amount needed by the California laboratory to get the orbiters ready for flight, with test equipment and facilities, would be $161 million. Cole attributed the high figures to recent increases in hardware requirements, accelerated delivery schedules, and more extensive test procedures. The Viking orbiter would require several major pieces of new hardware (table 28), and the designers at JPL had based their cost projections for this equipment on the master schedule given them by the Viking Project Office. But the people in California did not believe that the schedule was realistic. For example, the JPL engineers were convinced that such an early delivery date for the engineering test model of the orbiter would require a major acceleration of orbiter system and subsystem design plans, which in turn would demand an earlier selection and design of scientific....
 
 
 
 

Table 28 [whole page 171]

Major Test and Flight Hardware to be Developed by JPL for the Viking Orbiter

Scheduled Delivery Dates

Equipment

Purpose or Function of Equipment

As of 10 Feb. 1969

As of 13 Mar. 1969

As of 7 Aug. 1969

Orbiter structural test model (STM)

Also called development test Model (DTM). For qualification testing of basic orbiter structure, including vibration, static modal, and separation of orbiter from lander tests

mid-Feb.1971

 

15 Sept.1971

 

15 Aug.1971

 

Thermal Control test model (TCM)

Tear For thermal qualifications of orbiter systems. During tests, TCM to be mated with lander capsule thermal effects simulator to test effects on orbiter of lander heating. Both STM and TCM to be returned to JPL by 1 Aug. 1971 for laboratory testing.

1 Mar. 1971

 

1 Dec. 1970

 

1 July 1971

 

Engineering test model (ETM)

To validate physical and functional interfaces between orbiter and lander capsule and between spacecraft and people, procedures, and facilities associated with combined systems tests. To be assembled from early production components for orbiter; flight-qualified parts not necessary. Could be updated after tests for use in Deep Space Network compatibility testing and launch center testing.

1 Aug. 1971

1 Dec. 1971

1 Feb. 1972

Proof-test model (PYM)

To demonstrate orbiter design adequacy by performance of qualification tests, including vibration, shock, and thermal/vacuum. Also to be used for propulsion-system-interaction tests.

1 Feb. 1972

15 July 1972

1 Aug. 1972

Flight orbiters

Three flight-ready orbiters to be fabricated by JPL, two to be launched, and third to be held as backup before launch and as systems test vehicle during mission.

1 Aug. 1972

1 Sept. 1972

1 Oct. 1972

15 Oct. 1972

15 Nov. 1972

15 Dec. 1972

1 Jan. 1973

1 Feb.1973

1 Mar. 1973

 
SOURCE: "Viking Project and Design Requirements Specification", n.d., encl. to S.R. Schofield, "Minutes of the 17th Viking Orbiter Design Team Meeting Held 20 March 1969," memo, 24 Mar. 1969; Charles W. Cole to James S. Martin, "JPL Resource Requirements for Viking Project," 10 Feb. 1969; Langley Research Center, "Viking Project Orbiter System (VOS) Master Working Schedule," 13 Mar. 1969; and LaRC, "Viking Project Orbiter System (VOS) Master Working Schedule," 7 Apr. 1969.
 
 
[172]....instruments and related equipment than JPL had planned. These schedule changes would have to be translated into direct dollar increases. But even extra dollars could do only so much toward relieving the problems imposed by the increased tempo. Cole wrote to Martin, "In JPL's opinion, the significant schedule riskŠis not further reducible by bringing additional money and manpower to bear." What they would need was close coordination among the Viking Project Office at Langley, the lander contractor, and the JPL orbiter team to minimize the risks if they were to build a program that was "suitably balanced and mutually acceptable." 28
 
During the spring months of 1969, the orbiter schedules were revised by the project office to give Pasadena teams some more time and the budget a little breathing room. Rising expenditures, however, continued to be a major concern of Viking personnel on both coasts, although evaluating the budget promised to become a more comprehensible, concrete process once the agency selected an industrial contractor to design and build the lander. Only then would they be able to determine a firm figure for he cost of the entire project. 29 In late February 1969, NASA had issued a request for proposals for the lander and, on 29 May, selected Martin Marietta Corporation from the three bidders for the contract. With this choice made (discussed in chapter 7), the Viking project entered a new phase.
 
Early in June when Jim Martin and his colleagues met with representatives from the new lander contractor and JPL, nine working groups were established. Of these, one of the most important, from the perspective of the budget and scheduling, was the spacecraft interface and integration working group. Formed as the common ground for discussion between the Viking Project Office at Langley and the spacecraft builders at JPL and Martin Marietta, this working group allowed the three organizations to exchange information and ideas on spacecraft construction and hardware interface. Donald H. Kindt at JPL was named the Viking orbiter/lander capsule integration engineer. The interface-integration working group met for the first time on 10 and II June and. after their sessions, representatives from all three organizations took "action items" home to consider before they met again. 30
 
Another aspect of the increased tempo was the further proliferation of committees and working groups. By the end of June 1969, the amount of paperwork reaching Henry Norris's desk at JPL was growing dramatically. All managers in NASA programs, whether government or contractor employees, had to become accustomed to reading thousands of letters, memoranda, telexes, meeting minutes, reports, and other documents in the course of a project. Besides the meetings of the orbiter design team, 28 other conferences had been held by the end of June. The Viking orbiter project staff had held 12 meetings by 2 July, and the Viking orbiter mission design team started a new series of work sessions 30 June. By the time the orbiter was ready to fly the personnel of the orbiter design team (and its successor, the orbiter system design team), who oversaw the spacecraft's design and [173] fabrication would meet formally more than 250 times. The mission planners who worked out the flight details for the orbiter-navigation and tracking-met 143 times before the Viking launches.
 
Although Kermit Watkins noted as early as August 1969 that "we are beginning to become inundated with documentation," all the meetings and paper allowed Norris and his orbiter team to keep abreast of the myriad of details that went into planning and building the spacecraft. At the Viking Project Office in Hampton, Virginia, Jim Martin used similar tools to keep tabs on the progress or lack of progress of the lander. Viking was not brought to fruition by paperwork alone, but the mountain of documents the teams left behind provides some clues to the enormous number of man-hours that went into getting the project off the ground. 31
 
During the remainder of 1969, the Viking orbiter personnel worked on a number of key tasks in defining the design of the spacecraft and the nature of its scientific payload. Norris participated in the first meetings of the Viking Project Management Council; Norris, Watkins, and their colleagues worked out the second and third versions of the "Viking mission definition" document; orbiter staff members received a briefing on the preliminary science results of Mariner Mars 69; and the staff took part in the first quarterly review of the whole project. These activities were typical of activities during the next five years.
 
 
Viking Project Management Council
 
 
Jim Martin formed the Viking Project Management Council* in March 1969. Since Viking was the first planetary project in which several NASA centers and contractors would be participating in the design, development, and operation of major spacecraft elements, the project manager believed that a management council would "facilitate common understanding of the overall project objectives and provide a forum where technical and management problems can be freely discussed." At the first meeting, 18-19 August at the Martin Marietta factory outside Denver, each of the systems managers gave a brief status report on his organization's work to the 50 persons attending.
 
Henry Norris outlined the orbiter design, covering such topics as the relationship between the orbiter and lander during the cruise phase of the trip to Mars, the orbiter's weight budget, and communications equipment for the Viking spacecraft. Noting that orbiter and lander weights were a recurring concern, he told Martin and the other participants at the council meeting that a system of weight bookkeeping must be established between Langley and JPL. By this time, the entire spacecraft was projected to weigh [174] 3316 kilograms, with the weight of the orbiter at 605 kilograms without propellants. Jim Martin agreed; someone from the Viking Project Office would be assigned to the problem. Norris also reported that procurement had begun for the orbiter components and work was already under way on tasks that would require a long lead-time. The spokesman from JPL noted in summary that additional orbiter personnel at the laboratory would be selected shortly, including some persons that were finished with their Mariner 69 activities. 32
 
Once all the systems managers gave their reports, l3 working group chairmen presented information about their work. Norris later told his colleagues at the Jet Propulsion Laboratory that the sessions "proved to be very beneficial in helping to identify and clear the air on a number of interface concerns." In particular, the two days of discussion helped to clarify the roles and responsibilities of individuals and organizations. 33 Equally significant, it gave the managers from scattered geographic locations an opportunity to meet with one another. Face to face, they could take the measure of their colleagues as they worked on problems of mutual interest. This and subsequent meetings of the management council would force the men to work with other human beings, not faceless signatures on memos. The council was just one part of Jim Martin's strategy for forging a team from a group of disparate individuals and organizations.
 
* Membership in the council included J.S. Martin-chairman, W.J. Boyer, H.E. Van Ness, I Taback, F.W. Bowen-secretary, and E.A. Brummer, Langley; R.H. Gray, Kennedy Space Center; W. Jakobowski, NASA Headquarters, E.R. Jonash, Lewis Research Center; A. J. Kullas, Martin Marietta; and H.W. Norris and N.A. Renzetti, JPL.