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On Mars: Exploration of the Red Planet. 1958-1978
 
 
ORIGINS OF VOYAGER
 
 
 
[85] For the duration of the Voyager project, there were two distinct perspectives of the enterprise-one view from NASA Headquarters and another from the Jet Propulsion Laboratory in Pasadena. As with Ranger and Mariner, Voyager was initially a JPL undertaking, with nearly all the early study and design done in the California lab. In contrast, JPL had contracted out to industry for the design and development of Surveyor, the lunar soft-lander. This difference may have been indicative of the Pasadena team's bias for planetary missions but, for whatever reason, the team had a particular attachment to Voyager. JPL staffers had very specific ideas about how Voyager should be developed (orbiters first, with the addition of landers much later) and managed (loosely knit organization of delegates from various laboratory divisions). Furthermore, JPL wanted to conduct the total project within the walls of the laboratory. The West Coast planners favored small "manageable" undertakings, while NASA Headquarters called for centralized management under one responsible individual, with centers assuming a supervisory role over industrial contractors. As Voyager became a pet project with headquarters managers, the differences between JPL and Washington became obvious. In Pasadena, JPL personnel muttered about pencil-pushers who had no understanding of the problems of engineering the nuts and bolts of a Mars-bound spacecraft, and not uncommon in the nation's capital were exasperated remarks about the single-mindedness and independence found at JPL. While these differences were not responsible for the cancellation of the project, they made the work of Donald P. Hearth, responsible for Voyager at headquarters, and Donald P. Burcham, Voyager manager at JPL, more difficult. From the beginning, even Voyager's most optimistic supporters saw trouble ahead for the planetary spacecraft.
 
JPL planners began to study Voyager-class missions in 1961 to determined more clearly what flights with what size spacecraft would be a reasonable [86] step beyond Mariner B. In May 1962, the laboratory's Planetary Program Office commissioned a study of advanced missions and spacecraft. In addition to Voyager with flights to Venus and Mars, a second kind of advanced spacecraft was examined - Navigator, which would explore the sun, comets, Mercury, and Jupiter and require still more powerful launch vehicles. Under the direction of Phillip K. Eckman, the advanced planetary spacecraft study group, with representatives from all the technical divisions of JPL, examined large orbiter missions for Voyager because it believed that too little was known about the Martian and Venusian atmospheres to permit the development of spacecraft landing systems for either planet. One of the most important results of this initial phase of the advanced study was the determination of "the maximum orbiter-spacecraft payload." One member recalled that the group had been ``hard pressed to come up with an in-orbit payload in excess of 500 pounds [230 kilograms] of instruments'' for the "ideal" payload. 3 The group's work was the subject of three days of discussions by JPL and NASA representatives in early November 1962 (table 9).
 
Five men participated in the November Voyager review: Donald Hearth and Andrew Edwards, Jr., from headquarters; and Peter N. Haurlan, manager of the JPL Voyager study, Philip Eckman, and Robert J. Parks from JPL. Hearth, with NASA since 1962, was chief of Advanced Programs in the Lunar and Planetary Program Office and the key headquarters representative at the winter meeting. He had been an aeronautical research engineer at the Lewis Flight Propulsion Laboratory (of NACA) in Cleveland in the 1950s and a project engineer for Marquardt Corporation, where he had managed research related to hypersonic ramjets and similar advanced power plants. Hearth believed that fiscal 1963 activities were "proceeding along logical lines" and that JPL was doing a good job. However, he was disturbed by the postponement of work on landers, as preliminary research was necessary for comparison studies of alternative missions. Hearth preferred to push ahead with a total mission study, refining the details as new information about the planets became available.
 
A more pressing concern, according to Hearth, was the work load the Pasadena laboratory was assuming. "It appears to me that JPL is planning on doing too much in-house starting in 1964. Their plans for bringing in contractors next year looks good; however, I question the relative in-house and out-of-house level." Providing some overlap (with the JPL effort) from contractors appeared advisable, and Hearth expanded his thoughts on the subject in a memorandum to Oran Nicks:
 
l.) JPL (Haurlan) did not have complete information on Voyager expenditures thus far in FY63.
2.) JPL should have conducted mission capability comparisons (even on just a preliminary basis) earlier in the committee activity.
[87] 3.) Haurlan and [Eckman] did not have definite schedules for committee activities....[and] schedule charts were not available. Between the three of us, we made up such a chart during my visit.
4.) JPL is thinking of doing more of the Voyager job in future years in-house than is reasonable.
 
 
 

Table 9

Highlights of Advanced Planetary Spacecraft Group Investigation, 1962
 
 
Missions Considered
 
- Flyby-very short duration.
- Planetary orbiter-longer duration but does not permit examination of planetary surface.
- Direct landing- "most exciting" mission, but technological requirements for such mission are quite severe.
- Other-sample return, flyby or orbiter wim landing capsule, flyby with multiple capsules, etc.
- Conclusion -Advanced orbiter appears most feasible in period under study, 1966-1973.
 
General Mission Objectives
 
- Acquire sufficient environmental information to permit confident design of large landing vehicle, both manned and unmanned.
- Permit biological examination of the near planets.
- Investigate planetary atmospheres.
- Study planetary geology.
 
Major Technological Problem Areas
 
- Launch facility limitations-not enough launch pads for quick turnaround required by launch window schedule.
- Tracking system limitations-deep space network too limi ted to permit communication with multiple spacecraft.
- Spacecraft power limitations-need to improve both solar-cell and radioisotope-thermoelectric-generator technology.
- Sterilization-need to develop techniques for sterilization and develop hardware that can survive sterilization process.
- Flexibility-need to develop capability to incorporate new knowledge from one mission into the next, even with short interval between planetary opportunities.
 
SOURCE: JPL,"Advanced Planetary Spacecraft Study Report," vol. 1, EPD-139, 28 Dec.1962, pp II-1 to II-8, V-1 to V-2
 
 
Trying to maintain greater control over the progress of Voyager, Hearth asked the study group to provide NASA with monthly reports, quarterly [88] project reviews, and all back minutes of advanced planetary spacecraft study group meetings. Hearth made a final point that would have discomfitted the team in Pasadena. From "the current situation," it appeared likely that JPL, could manage Voyager in future years, but there was the chance that NASA Headquarters might decide otherwise. "If another NASA Center or if a strong industry contractor [was] to manage the project." Hearth thought that "they should be brought into the project now because the studies being conducted this year will establish the system design concept to be followed in future years." 4
 
NASA had been considering broader industry participation in the Voyager project since early l962, 5 and eight companies had active, internally sponsored concept studies in progress:
 
 

Continuous study during the last 9-12 months

AVCO

General Electric

Study during the last few months

Douglas, Santa Monica

Convair, San Diego

Convair, Fort Worth

Study just starting

Lockheed, Sunnyvale

North American Aviation, Space and Information Systems Div.

Space Technology Laboratories

 
In addition to the JPL exercise that would cost $700 000, Hearth recommended to Nicks that headquarters fund two industrial contractors ($75 000 each) to conduct mission and predesign studies. From their findings, two systems would be selected for further study.
 
Industrial participation would have four advantages according to Hearth. First, "it would provide a 'check' on the JPL results. This is important since a decision will, presumably, be made this year which will determine the approach to a system involving many millions of dollars." Second, NASA would have a wider base of "funded Voyager studies" in the event that Voyager management did not go to JPL. Third, by investing $150 000, NASA "would provide encouragement to the management" of numerous companies by demonstrating that NASA was "serious about Voyager" and that a substantial part of the task would be assigned to industry. Finally, contracts with industry would allow NASA to direct the studies "along lines desired" by the agency, and Hearth had no doubt that considerably more than $75 000 would be expended by each company in its studies. "In addition, the agency would gain an "early insight into the firm's capability for Voyager." 6
 
Whereas Hearth had planned to contract with AVCO or General Electric for this short-term study, with a more elaborate preliminary design project in fiscal 1964, the lure of money brought a number of other contractors [89] onto the scene. 7 The original plan for a six-month contract starting 1 January was replaced by a 5 March 1963 competitive request for proposals for a formal design study. 8 With an eye on a 1967 launch to Venus, Hearth decided that he cold not afford to sacrifice six or seven months on a preliminary exercise. He told the NASA senior management at a February briefing for Administrator Webb that it would be difficult to meet the next Venus launch opportunity less than four and a half years away, but the undesirable alternative was to wait six years to launch the first planetary spacecraft (Mars 1969) "having the mission capability and scientific return possible with Voyager." Hearth believed strongly that they should set June 1967 as their goal. 9
 
 
Request for Proposals-Voyager
 
 
Aiming for 1967 and 1969 launches to Venus and Mars, the NASA Headquarters staff decided to spend about $200,000 in 1964 On two contracts to examine mission and predesign aspects of a Voyager flight.10 "Request for Proposal No. 10-929, Voyager Design Studies" was sent to 21 companies 5 March 1963. Potential contractors were to summarize their cost and scientific proposals-based on NASA's statement of work defining the projected studies-for developing an advanced spacecraft to perform "orbiter/lander missions to Mars and Venus from 1967 through 1975." 11 This Voyager-class spacecraft, launched by a Saturn booster, would be capable of more difficult missions than Mariner, carry more scientific instrumentation, collect and return more data, and have a longer operational lifetime.
 
Two contractors would be given six months to recommend their design concepts. Their proposals would consider both the orbiter and the lander and evaluate landers that could be released both before and after achievement of planetary orbit. Flight weight was set at 2700 to 3175 kilograms, the planetary payload for the Saturn IB booster, but smaller craft (1800 kilograms) would also be examined in case the Air Force Titan IIIC launch vehicle were employed instead. Growth of subsequent Voyager craft to weights as great as 27 000 kilograms was another area of study. Spacecraft in the heaviest class could be sized to fit the Saturn V, called the Advanced Saturn. Don Hearth was the technical director for this phase of the Voyager investigations. 12
 
A total of 37 industrial organizations was represented at the Voyager preproposal briefing at NASA Headquarters on 11 March 1963, where delegates had the opportunity to ask questions before they finalized their proposals, due on the 25th. 13 Of the 13 companies submitting proposals, 10 were judged acceptable. A technical evaluation team * met on 27 March to begin the selection process. Using an elaborate formula, the team decided that the Missile and Space Vehicle Division of General Electric, Valley [91] Forge Space Technology Center, Pennsylvania, was the clear first choice. While other companies were competitive from a cost standpoint, only AVCO Corporation,** Lockheed Missiles & Space Company, and Space Technology Laboratories, Inc., had submitted technically acceptable proposals. After careful scrutiny, the evaluation team favored awarding the second contract to AVCO. Although AVCO's "proposal was not as smooth and as well organized as the Lockheed proposal, it did demonstrate a better understanding of the scope of the technical study." 14 The two contractors were notified of their selection in early April.
 
 
 
Table 10 [whole page 90]
Ranking of Contractors Bidding on 1963 Voyager Study

Contractor

Overall
Rank
Composite Score
(of possible 600)

Total Cost Estimated (cost rank)

Fee Requested

Overhead Rate
Man
Hours
G & A*
Rate
Computer
Time

Missile and Space Div., General Electric

1

524.5

$125 000 (6)

8.0%

120%

6 100

10.5%

9 000

Research and Advanced Development Div., AVCO

2

443.4

144 546 (7)

7.0

105

9 131

8.0

13 200

Missiles & Space Co., Lockheed Aircraft Corp.

3

406.5

122 315 (5)

7.0

80

8 530

6.5

3 500

Space Technology Laboratories

4

358.6

169 189 (8)

8.5

103

10 850

9.9

---

Space and information Systems Div., North American Aviation Inc.

5

337.8

---

---

---

---

---

---

Aeronutronics Div., Ford Motor Co.

6

334.4

96 109 (1)

0.0

131

4 284

0.0

---

Martin Marietta Corp.

7

332.6

186 505 (9)

7.0

102

19 184

16.9

---

Aerospace Div., Boeing Co.

8

301.9

---

---

---

---

---

---

McDonnell Aircraft Corp.

9

276.4

98 939 (3)

12.0

80

7 080

6.6

---

Astronautics Div., General Dynamics Corp.

10

265.7

99 944 (4)

7.0

47

7 335

7.17

---

International Telephone &Telegraph

11

---

97 916 (2)

0.0

125

9 480

12.9

---

 
--- data not available.
 
* General and administrative; expenses such as executive salaries.
 
SOURCE: Donald Hearth and Andrew Edwards to Carl M. Grey, "Technical Evaluation of Proposals Received in Response to RFP No.10-929," 2 Apr.1963; Hearth , note of conversation with Grey and R. W. Lord, 4 Apr. 1963; and Grey. "Technical Evaluation of Proposals," 4 Apr. 1963.
 
 
Contractor Proposals
 
 
Despite public and congressional scrutiny of Voyager, the contractor studies were conducted as planned during the summer months of 1963.15 General Electric secured the services of 20 distinguished scientists to review the company's progress and "suggest modifications which would increase the overall scientific value of the program.'' Several familiar names were on the list-Melvin Calvin, Joshua Lederberg, Wolf Vishniac, Carl Sagan, Harold Urey. 16 Scientific community and industry were working together for their mutual benefit.
 
A host of technical questions were being examined by the contractors, as the following list sent to the Voyager project managers at AVCO and General Electric indicates:
 
l. What can Voyager do scientifically that Mariner B cannot do?
 
2. How large a Mars lander is required for long lifetime (one month or more)?
 
3. If a relay orbiter is employed, what is the trade-off between lander data rate, science payload weight, and lifetime?
 
4. How does Martian lander performance (data rate, science payload, and lifetime) and weight compare with and without a relay orbiter?
 
5. What are the problems associated with the use of a high-gain directional antenna on the Martian surface?
 
6. Can such an antenna be designed and developed for a '69 mission (without undue risk) based upon what we currently know and expect to learn about the planetary surface in the near future?
 
7. If the answer to question 6 is no, what type of additional scientific data is required?
 
8. Will a Voyager lander and relay plus science orbiter system be capable of obtaining the type of data indicated by the answer to question 7?
 
9. Once these data are obtained, how much time will be required for the design and development of a high-gain antenna (for landers) for use in a flight mission?
 
[92] 10. How heavy must a Martian lander be if it is to use a high-gain antenna?
 
11. Is an orbiter really necessary? For science? For communications relay? If an orbiter is necessary, must it be used simultaneously with a lander? Can basic orbiter spacecraft be designed to be modified efficiently from a science plus relay orbiter to a pure relay orbiter?
 
12. What is the trade-off between orbiter science weight and lander science weight?
 
13. What is the minimum weight of a pure relay orbiter as a function of data rate? Of a pure science orbiter?
 
14. How does the weighs of a science plus relay orbiter compare to a relay orbiter?
 
15. Can an orbiter he designed (with or without minor modifications) to perform both Mars and Venus missions? How much of a eight penalty results from designing an orbiter for both Mars and Venus compared loan orbiter for only Mars?
 
l6. What are the critical technology problems associated with Voyager? What is the development time and cost? What will flight units cost? On what experience is this based?
 
17. Starting with the 1969 opportunity, what type of Voyager program for Mars is possible with the changing energy requirements between 1969 and 1975? 17
 
Before any hardware could be developed for Voyager missions to the near planets, all these many complex technical issues had to be resolved by NASA and its contractors. Time, however, was an issue of equal importance, By early fall 1963, no one at the space agency still considered a 1967 launch to Venus practical, and a mission to Mars in 1969 seemed even less likely. 18
 
Growing friction between Hearth's office at headquarters and JPL's Advanced Planetary Spacecraft Study Group was another negative factor, The study group continued to stress the orbital portion of Voyager's mission and exclude the lander from its research. During the second phase of its study, which paralleled the AVCO and General Electric contracts, the team in Pasadena turned its attention to orbiter missions in the 2700 to 3175- kilogram class and during a third phase examined the technical aspects of joining and later separating an orbiter and lander. However, the work did not include studies of the lander itself. In fact, the engineers at JPL were growing increasingly skeptical about the desirability of an orbiter-lander spacecraft. 19
 
Since NASA Headquarters had assumed control of Voyager, the laboratory managers had become resentful over the allocation of Voyager work and responsibility among the NASA centers. A memorandum for internal use only at JPL recorded that the laboratory had been directed by NASA [93] Headquarters to terminate its Advanced Planetary Spacecraft Study (APSS) as of September 1963. Later analysts explained JPL's perceptions of the controversy:
 
Many factors probably played a role in this decision; one of these was the reporting of recent Mars observations, indicating that the surface pressure was much less than had been previously estimated, making the problem of successful entry and descent more difficult. Another reason appears to be budgetary considerations. A third reason, though never publicly expressed, may have been related to certain political questions related to the future of the Laboratory and whether or not it was to be directly involved in planetary landing missions. The fourth and most pressing reason was the initiation of the Mariner 1966 project and the lack of available manpower to support APSS work concurrently. 20
 
Early in 1963, three JPL scientists-Lewis D. Kaplan, Guido Munch, and Hyron Spinrad-had revealed new data about Mars that had serious implications for proposed Mars landing studies, The new estimate for the surface level atmospheric pressure was 10-40 millibars, or one-third the previously estimated pressure. 21 Homer Newell called a special colloquium for l October 1963 to discuss the subject. As Newell later told members of the Senate Committee on Aeronautical and Space Sciences, a dozen or so planetary astronomers could not agree on the best figure, and their estimates ranged from 10 to 115 millibars. While Mariner 4 would resolve this issue in the summer of 1965, the uncertainty did cause concerns-though not insurmountable ones-for the Voyager team in the interim. AVCO and General Electric were given an extra month to examine the implications of the lower pressure for their proposed landers. 22
 
The JPL budget was not an inconsiderable issue. The space science budget was tied to the shuffling of the Mariner flights during 1963. As Oran Nicks pointed out to the Administrator in a 1963 year-end review, several flights planned for 1964 had been eliminated, including the Venus missions that would have duplicated the successful Mariner 2 . Turning to the Mars aspect of the planetary program, Nicks told Webb that the two Mariner B flights planned for 1966 had been scrapped because of "recent budget problems for Fiscal Years 1964 and 1965." Mariner B with its small, biologically oriented landing capsule had begun to compete for Voyager dollars, Instead, a reincarnation of Mariner B-Mariner l966-with a lighter and less expensive capsule had been scheduled for two Centaur-powered flights in 1966 to determine the constituents of the Martian atmosphere and obtain more accurate measurements of the surface pressure. While there was still time to prepare for a Venus mission in 1967, the fiscal 1965 budget crunch seemed to preclude such a flight. If Voyager funds were cut back or dropped entirely from the 1965 budget, a planetary mission would not be possible before 1971. 23
 
[94] JPL's contention that the lab's future was inextricably bound to NASA politics over what center would manage the agency's planetary projects, had a hollow sound to it, as did claims about manpower shortage. Hearth and his associates in the headquarters Advanced Programs and Technology Office were the first to acknowledge the crucial and central role that JPL had played in the NASA planetary program, but in a late summer memo Hearth told Nicks that JPL was using Voyager as a hostage to induce the agency to increase its manpower levels. "As you know, JPL has been going through a detailed evaluation of their personnel assignments as a result of their current man-power ceiling.'' It appeared to Hearth that JPL would not be submitting a proposed project development plan for Voyager or the cost and schedule information that headquarters needed. Apparently, the lab would "dissolve the Advanced Planetary Spacecraft Study Committee which essentially [would] terminate the current Voyager activity at JPL." 24 Simply put, the managers in Pasadena had decided not to work on Voyager during 1964. This did Slot quite agree with JPL's position that the laboratory had been "directed to terminate its APSS work."
 
Hearth was sure it would mean trouble for the project if JPL were to use Voyager to garner more job slots, but he argued that without Pasadena's assistance his office would be crippled. "In addition, we cannot propose a program without a center ready and willing to accept project management." Although he could delay his Voyager recommendations to the NASA managers for six months while his team selected another center or for one year while they waited for JPL, either of those delays would "jeopardize the chance for a 1969 Voyager launch." Hearth frankly felt that JPL was being "short-sighted" and would be left "without significant programs in another 2 to 3 years without Voyager." But he also had an inkling that some people at NASA Headquarters also wanted to delay Voyager. "Obviously, NASA management may decide to defer Voyager indefinitely," but he did not want that to happen without their having "all the technical and scientific facts available.'' 25
 
Hearth presented the Voyager case at a December 1963 planetary program briefing for Administrator Webb. Summarizing first the Mariner program to date, he noted that the revised figures for the Mars atmospheric pressure, coupled with budget problems, had led to the termination of Mariner B. To survive a hard landing, a capsule would have to weigh at least 360 kilograms, and Atlas-Centaur could not be expected to deliver more than about 225 kilograms. The new Mariner 1966 would use a chassis like Mariner 4 's to transport a small atmosphere probe to Mars. Turning to Voyager, Hearth discussed the JPL, AVCO, and General Electric concepts as they had emerged during the April to October study. 26
 
Engineers for AVCO and GE had studied Mars and Venus missions, with AVCO giving Venus greater attention, but it was obvious to both contractors that Mars was NASA's primary target. General Electric recommended two identical landers carried aboard a single orbiter bus. Primary [95] communications from the landers to Earth would be via a relay in the orbiter, with secondary links directly from the landers. Solar cells and batteries would be used to power the orbiter, while radioisotope thermoelectric generators would provide both electricity and heat for the lander. Having concentrated basically on Mars missions, the General Electric engineers emphasized "biological and geophysical-geological experiments," recommending Syrtis Major (10°N., 285° long.) as a landing site for one lander and Pandorae Fretum (24°S, 310° long.) for the second. These were two of the more interesting areas for biological exploration. The appearance of Syrtis Major did not change much with the seasons. Its boundaries "are sharp and stable, and it is one of the darkest areas of the planet." Pandorae Fretum did change with the seasons, the dark color developing in spring, deepening with summer, and becoming light in the fall for the duration of winter. While the choice of these sites would eliminate close examination of the polar regions and the "darkening wave," they considered their choices the best ones "in view of the high priority of the life detection [experiments] and the eventual requirements for choosing sites for manned landing missions," 27 GE would wait until after the first successful landings to define future sites, but AVCO made the proposals in table 11. 28
 
General Electric proposed a rather ambitious series of scientific investigations, considering the weight limits on instrumentation for both the orbiter (98 kilograms) and the lander (70 kg). Biological instruments would easily constitute a third of the payload projected for the lander, AVCO Corporation's landed science payload was greater (91 kg), but the proposed orbital instrumentation was less (61 kg). In either case, the weight was substantially more than the 23 kg of experiments that could have been landed with a Mariner B-class capsule. During more favorable Mars launch....
 
 
 

Table 11

AVCO Proposals for Missions to Mars, 1963

Launch Opportunity

Lander

Landing Site

Latitude

Longitude

1969

1

Solis Lacus

28°S

90°

2

Syrtis Major

15°N

286°

1971

1

South Polar Cap

83°S

30°

2

Mare Cimmerium

18°S

235°

3

Lunae Palus

15°N

65°

4

Aurorae Sinus

15°S

50°

1973

1

Popontis

45°N

185°

2

Elysium

25°N

210°

1975

1

North Polar Cap

78°N

220°

2

Nepenthes-Thoth

25°N

225°

 
 
[96]....opportunities-1971 and 1973-larger scientific packages could be landed using the same orbiter and launch vehicles.
 
Besides the weights of the landers (GE, 657; AVCO, 762), the major difference between the two contractors' approaches was the number of landers; one for AVCO and two for GE. AVCO's lander was encapsulated before launch for sterility and for protection during the descent. The blunt body of the aeroshell would protect the lander during entry and slow the descent. A parachute, deployed when the aeroshell and heatshield were discarded, would slow the craft further. At impact, the lander would be protected by aluminum crush-up pads (touchdown velocity 12 meters per second). After a relatively hard landing, the craft would roll and tumble until it came to a stop, and six petals, which when closed protected the internal parts, would open and erect the lander and raise it off the ground. AVCO also planned to use radioisotope thermoelectric generators to provide electricity. General Electric's capsules by comparison were much simpler. They consisted of "moderately blunt sphere cones," which entered point downward instead of blunt end down as with the AVCO approach. General Electric proposed to use rockets, tip bars, and explosive anchors to orient the cone once it was on the surface.
 
Hearth told Webb at the December briefing that "the areas of agreement were quite significant even though the studies were conducted independently and separately of one another." Both contractors called for similar scientific capabilities, and "they agreed quite well on the prime technical problems and development problems" were. But would NASA underwrite Voyager missions to the planets beginning in l969? 29
 
 
Mariner 1966 and Advanced Mariner
 
 
Hearth's attempt to sell the NASA management on a 1969 Mars Voyager was unsuccessful. The administrator decided that the resources required-manpower and dollars-made it too ambitious for a 1969 mission. He preferred to defer the first Voyager launch until 1971. With the first manned lunar landings accomplished, the space agency would be under less political and financial pressure, and Voyager could proceed. To fill the gap between the 1964 Mariner C flyby and the 1971 Voyager orbiter-lander, NASA's planetary program staff proposed to add a 1968-1969 Advanced Mariner to the schedule so supplement a Mariner 1966 Mars atmospheric capsule mission. 30
 
A Mariner 1966 mission would "make maximum use" of Mariner 1964 technology. 31 Plans called for a nonsurviving atmospheric capsule that would crash onto the Martian surface after it had relayed its scientific data. But not everyone favored the concept, since it added new technological problems in several areas-planetary atmosphere entry dynamics, communication links between a flyby craft and capsule, and sterilization. NASA planners began discussing l966 capsule in January 1964, and it quickly became apparent that JPL did not favor the idea. 32
 
 
 
Table 12 [97]

Voyager System Weights from 1963 Contractor Studies

System

General Electric
(kg)
AVCO
(kg)

Orbiter
Structure

190

147 (includes thermal control)

Harnessing

48

---

Power supply

99

209

Guidance and control

103

84

Communications

131

128

Thermal control

40

---

Propulsion (dry)

212

209

Diagnostic instrumentation

13

---

Payload (scientific)

98

61

Total

934

838

Lander

2 landers

1 lander

Heatshield

41

204 (includes structure)

Structure

181

95 (adapter sterile can)

Retardation

72

---

Thermal control

41

---

Power supply

51

136

Orientation

26

91

Communications

65

145 (touchdown and deployment)

Payload deployment and installation

25

---

Spin and separation

19

---

Retrorocket

45

---

Adapter and radiator

21

---

Payload (scientific)

70

91

Total

657 each

762

657

-

Fuel
Orbit insertion and midcourse

939

1361

TOTAL

3187

2961

 
SOURCE: General Electric Co., Missile and Space Div., Valley Forge Space Center, "Voyager Design Study ", vol. 1, "Design Summary " 15 Oct. 1963: and AVCO Corp., Research and Advanced Developmenz Div., "Voyager Design Studies," vol. l., "Summary," 15 Oct. 1963, p. 111. All metric conversions are to nearest kilogram.
 
 
By mid-March, Hearth told Oran Nicks that he was compelled to recommend eliminating the capsule from the proposed Mariner 1966 mission. JPL, understaffed and unenthusiastic, would not support the project if it included a capsule, and it was too late to assign the "entry probe" to another center. Considering the technical risks of the capsule, Hearth had to yield in face of the laboratory's intransigence.
 
NASA's fiscal 1965 budget would not support the Mariner 1966 project either. The $5.25 billion approved by Congress was $195 million less than [99] the agency had requested. Administrator Webb announced that NASA would maintain the momentum and direction of its programs despite the loss of anticipated funds, while meeting its lunar goals. Although the decision did not "involve the transfer to manned space flight of funds from space science," those programs would "required some adjustments." Mariner 1966, however, was doomed. According to the news release issued at NASA Headquarters, "the combination of a heavy workload at the Jet of applying our resources to a major advance beyond the limited Mariner" made it "unwise" to undertake a Mars mission in 1966 with the current Mariner spacecraft. Development of a spacecraft "with much greater scientific promise for launch to Mars in 1969" was being initiated. 33
 
 

Table 13 [Whole page 98]

Experiments Recommended for Voyager 1969 in 1963 Contractor Studies

General Electric

AVCO

Orbiter
Orbiter

Biological
Biological
Television survey
Infrared spectra of surface
Infrared spectrum survey

Geophysical-geological

Geophysical-geological

Stereo-television mapping
Television mapping
Magnetic lield survey
Magnetic field survey
Charged particle flux survey
 
Radio absorption (lander to orbiter)
Spectral albedo.

Atmospheric
Atmospheric
Ionosphere profile
Infrared radiometry of surface
 
Infrared emission

Space environment

Micrometeoroids

Magnetic fields

Landers (2)
Lander (1)

Biological

Biological

Growth
Biological detection
Metabolic activity
Microscopic examination of soil
Existence of organic molecules
Chemical structure of soil
 
 
 
 
 
 
 
Existence of photoautotroph
Turbidity and pH changes
Microscopic characteristics (TV)
Organic gases
Macroscopic forms (TV)
Surface gravity

Geophysical-geological
Geophysical -geological
Surface penetrability
Television mapping
Soil moisture
Magnetic field
Seismic-activity
Solar optical absorption
 
Surface gravity

Atmospheric

Atmospheric

Temperature
Temperature
Pressure
Pressure
Density
Density
Composition
Composition
Altitude
Wind velocity
 
 
Light level
Electron density
 
SOURCE: General Electric Co., Missile and Space Div., Valley Forge Space Center, "Voyager Design Studies" vol. 1, "Design Summary," 15 Oct. 1963, p. 2-2; and AVCO Corp., Research and Advanced Development Div., "Voyager Design Studies:' vol.1., Summary," 15 Oct. 1965, p. 9.
 
 
Canceling the 1966 capsule called for changes in Mariner 1964 and the Advanced Mariner (Mariner 1969). Hearth recommended flying the 1964 Mariner on an occultation trajectory-the spacecraft would fly behind Mars as viewed from Earth. A radio signal would be transmitted as the craft approached the planet, and that signal would be blocked as the craft passed behind it. Analysis of the behavior of the radio signal could determine more precisely the composition and density of the Martian atmosphere. *** 34
 
At the loss of the 1966 Mars mission in July 1964, Hearth called for an immediate study of the capsule for the 1969 Mariner. Early study was essential if Nicks' Lunar and Planetary Programs Division was to coordinate its plans effectively with Orr Reynolds' Bioscience Programs Division, which was working toward a 1 August 1964 deadline for a proposal for a "minimum acceptable" biological lander payload for 1969. Hearth believed that should sufficient information be "obtained over the next three years on the Martian atmosphere,Ša survivable biological lander is possible in 1969." He also thought that a lander mission was "preferable over an orbiter mission although the orbiter will be given careful study." 35 Hearth explained this in detail for Nicks because he did not believe that JPL could handle the entire Advanced Mariner mission, even if industrial contractors were used. The problem as Hearth saw it was choosing a NASA center to assist JPL. To assign Mariner 1969 to one organization and Voyager to [100] another would be unwise, because "the missions and spacecraft are too closely related." For Hearth, the only solution was to assign another center the responsibility for some portion of either Mariner 1969 or Voyager. "It is logical that this be the capsule. There is no question that such an arrangement will be difficult, to say the least," but he could see no alternative. Three centers could possibly assist JPL with its planetary work-Goddard, Langley, or Ames. Because of their earlier interest in the landing capsule for Mariner 1966, Hearth recommended the Ames Research Center team at Moffett Field, California. 36
 
 
* D. Hearth, chairman, B. C. Lam, A. Edwards, E. A. Gaugler, F. D. Kochendorfer, P. N. Haurlan, and L. E. Richtmyer.
 
** Reentry research was a strong point with AVCO, since it had worked with the Air Force in 1956 and 1957 to develop the heat-sink reentry vehicle.
 
*** If all other factors producing apparent motion of the spacecraft were accounted for (e.g., the actual motion of the spacecraft, the motion of the deep space stations on the rotating Earth, the lengthening of the transit time of the signal, and the refractivity of the Earth's lower atmosphere), the remaining unexplained changes in the radio signal could be attributed to refraction by the atmosphere of Mars. (For a successful experiment, it was necessary to account for the total change in frequency or phase of the signal due to all causes other than refraction by the Martian atmosphere to an accuracy of at least one part in 1011.) Since the geometry obtained from the estimated trajectory is known, the measured changes could be used to estimate the spatial characteristics of the index of refraction (or refractivity) in the electrically neutral atmosphere and electrically charged ionosphere of Mars. Thus, by measuring and then analyzing the changes in the characteristics (frequency, phase, and amplitude) of the radio signals from the spacecraft, it was hoped to learn more about the composition, density, and scale height of the Martian atmosphere." NASA, Mariner-Mars 1964: Final Project Report, NASA SP-139 (Washington, 1967), pp. 316-17.