LUNAR IMPACT: A History of Project Ranger

Part I. The Original Ranger

Chapter Three - SPACE SCIENCE AND THE RANGER MACHINE

All through the managerial fracas, JPL engineers had been pushing ahead with the design of the Ranger spacecraft. The origins of the evolving Ranger machine went back to March 1958, when Major General John B. Medaris, Chief of the Army Ordnance Missile Command, had authorized JPL to evaluate a new launch vehicle based on the Jupiter and eventually known as Juno IV. Paper analyses concluded that Juno IV could inject several tens of kilograms into deep space trajectories. That prospect was enough for JPL Director Pickering. Eager to leapfrog beyond the moon and begin exploring the inner planets before the Soviets, he instructed Daniel Schneiderman, in charge of JPL's payload design group, to define the technology and preliminary concepts for a Juno IV planetary spacecraft, one that would weigh some 134 kilograms (300 pounds) and could be guided to an encounter with Mars. 1

A PLANETARY MACHINE FOR SPACE SCIENCE

John Small, Chief of Mechanical Engineering, assigned a few engineers to work with Schneiderman on the new spacecraft design: James Burke, Walter Downhower, Marc Comuntzis, and John Casani. For some weeks this group devoted considerable time to the problem of radio communications. To communicate adequately from planetary distances, the spacecraft would require a high-gain antenna–in conventional terms, a narrow-beam "dish" mounted and hinged so as to point continuously at the earth. There, sensitive receivers, powerful transmitters, and very-high-gain antennas would complete the circuit. All the while, the spacecraft dish antenna would have to be kept pointing in the right direction through an appropriate method of stabilizing the attitude of the spacecraft itself. Early American spacecraft, such as the Explorers and Pioneers, had been stabilized by spinning the vehicle along its roll axis. For flights to the planets, JPL engineers deemed it necessary to have complete control of the spacecraft in all three axes, roll, yaw, and pitch. This would ensure precise pointing of the experiments and the antenna, and maximize solar power collection and thermal control (Figure 18). With full attitude control, the flight trajectory of a planetary spacecraft could also be refined by igniting a rocket engine on board in a "midcourse maneuver." A small rocket would be able to compensate for minor guidance errors introduced by the launch vehicle, thus permitting the spacecraft to approach more closely or even hit a celestial target. 2 In June 1958 a Pickering appointed JPL review team approved these preliminary design concepts. 3


 

Fig. 18. Spacecraft Attitude Stabilization in Three Axes


The planes of movement through which the spacecraft passes are illustrated above. The attitude of the spacecraft is established and maintained by commands executed by the attitude control system in conjunction with other systems of the spacecraft the attitude control system regulates the movements of the spacecraft in these three planes and accomplishes these movements by imparting small amounts of thrust to the spacecraft bus by the discharge of nitrogen gas from cold-gas jets positioned on and about the hexagonal frame of the spacecraft. The desired posture of the spacecraft is dictated by its spatial relationship with the sun and earth. It must keep its solar panels facing the sun for solar power and the high-gain antenna facing earth for communication. The sun and earth sensors, part of the attitude control system, continuously generate signals which are combined with information from the rate gyros of the autopilots. The latter supply the information defining the rate of movement. This combined information is translated by the attitude control system into commands to the appropriate cold-gas jets or combination of jets. This cycle is repeated until the desired attitude of the spacecraft is established and subsequently continues to function maintaining this posture.

Though the Juno IV program was canceled in October 1958, 4 the JPL martian spacecraft continued to evolve, now to be used in Project Vega. In addition to the features of a high-gain antenna and full attitude stabilization, engineers designed the spacecraft so that its longitudinal axis would point continuously toward the sun (except during midcourse or terminal maneuvers), since it was uncertain whether the earth could be "seen" by onboard sensors at planetary distances. This decision simplified the problem of maintaining thermal equilibrium on the spacecraft and permitted the use of solar cells on fixed panels as a primary source of electrical power. 5 With the Vega launch vehicle, JPL's Schneiderman and his colleagues also had more ample weight figures with which to work. Assuming a parking orbit technique, in which the spacecraft is ultimately launched into the solar system from earth orbit, Vega calculations yielded spacecraft weights of 360 kilograms (800 pounds) deliverable to the vicinity of the moon, and approximately 205 kilograms (450 pounds) to Mars or Venus. 6

But at the start of the space program, the additional spacecraft weight was inseparable from the expensive and unproved Vega launch vehicle. The higher launch costs would ultimately mean fewer flights. The unproved launcher would also likely fail in some early missions; estimates of reliability for the individual Vega stages ran at about 0.5. Each flight could be expected to have less than half a chance of succeeding even if one were to neglect any failures that might occur in the complex spacecraft. To enhance reliability, therefore, members of the JPL design group decided to use a single spacecraft design repetitively. They identified and combined functions common to all flights, with the resultant basic unit termed a spacecraft "bus." Here the design would vary as little as possible for each mission. The bus would provide electrical power, communications, attitude control, command functions, and a midcourse maneuver capability. To the bus would be added the scientific instruments and associated equipment that together comprised a mission package. 7

Since nearby equipment could adversely affect many kinds of scientific experiments (limits on fields of view, radio or magnetic interference, etc.), tall structures and extendable booms were called for. Like a chrysalis, the craft with its solar wings would be folded into a compact and rugged package inside the conical aerodynamic nose fairing of the launch vehicle, then open out in space while cruising to Mars or Venus. By mid-1959 these preliminary plans had been communicated to NASA and described to Congress. 8 They would provide the basic model for the Ranger machine (Figure 19).


 

Fig. 19. Vega Spacecraft Model


THE VEGA-RANGER: HERE PLANET AND SKY SCIENCE MEET

The JPL Space Sciences Division, meantime, drew up a program of experiments for the Vega flights. Created in the reorganization that followed JPL's transfer to NASA, this division drew together JPL experimenters in one group, prepared instruments for flight missions, and processed the information returned to earth for release to the experimenters. 9 As chief of the new division, Pickering named Albert R. Hibbs, an articulate, exceptionally bright young physicist with a Caltech Ph.D. One of the founders of the Lunar and Planetary Exploration Colloquia and a participant in the Explorer and Pioneer IGY projects, Hibbs was already well known within the community of space scientists and engineers.

When Glennan decided to emphasize the lunar objective in July 1959, neither Hibbs nor his JPL engineering colleagues abandoned the martian spacecraft. They preferred to stick with it even though on a 66-hour flight to the moon batteries could suffice in place of solar panels, and a high-gain antenna was unnecessary for communicating over a distance of 400,000 kilometers (a quarter million miles). Adapted to lunar missions, the high-gain antenna, instead of being used for long-range, narrow band communication, would now be used for relatively wide-band transmission such as television at lunar distances. The bus and passenger concept, three-axis attitude stabilization, and solar power, its designers reasoned, could be used to develop the technology required for the planetary flights postponed to 1962. 10

The question of just what scientific experiments the Ranger machines would carry was a matter for decision not only by JPL but by NASA Headquarters, particularly Silverstein's office of Space Flight Programs. Silverstein had awarded the responsibility for determining what scientific instruments would ride into space to his quiet assistant director, Homer E. Newell. A crew-cut, 44 year-old scientist administrator, Newell was the son of an electrical engineer, who had helped him provision a chemical laboratory in their home in Holyoke, Massachusetts. His mother, an accomplished musician, inspired dinner time exchanges concerning events of the day. Newell, who earned his Ph.D in mathematics from the University of Wisconsin, joined the Naval Research Laboratory after World War II. He was soon appointed head of the Rocket Sonde Branch, and then, a few years later, Superintendent of the Atmosphere and Astrophysics Division. Together with James Van Allen, Lloyd Berkner, and other members of the ad hoc Upper Atmosphere Rocket Research Panel, he directed America’s postwar assault on the physics of the upper atmosphere, seeking answers to theoretical questions involving earth-sun electromagnetic relationships. Revealing the type of science he preferred, Newell assured the readers of his first book that "the ultimate technical strength of the nation is to be found in the continuing accumulation of fundamental knowledge" (Figure 20). 11


 

Fig. 20. NASA Space Flight Programs Assistant Director for Space Sciences Homer Newell


In October 1958, after serving as Science Program Coordinator for the IGY Vanguard Satellite project, Newell moved to Silverstein's office in the fledgling NASA. He promptly established procedures for shaping the agency's space flight program. In arrangements worked out in succeeding months, the Space Science Board of the National Academy of Sciences contracted to provide advice on long-term goals to NASA. While specific research objectives and operating policy were of course prerogatives reserved to the space agency, Newell recognized that the success of the research program would ultimately depend upon the support it could command within and outside the agency, especially from those scientists engaged in its work. He elected to employ small contingents of qualified scientists at Headquarters and the field centers. In accord with the precedent of the IGY and sounding rocket programs, he chose to delegate the bulk of NASA's basic space research, primarily to university scientists. NASA would tap the best scientific talent available in the nation, and the best scientific talent, Newell hoped, could be expected to provide vocal and articulate support for NASA's science program. 12

Newell's office made known the opportunities for conducting space research from NASA satellites and space probes to university scientists directly by correspondence, in announcements at annual meetings of the various science societies, and by means of special conferences convened for that purpose, including the first national Conference on Space Physics sponsored jointly by NASA, the National Academy of Sciences, and the American Physical Society in April 1959. 13 Numerous proposals for experiments-both solicited and unsolicited-arrived in short order. In fact, Newell received far more proposals than could be accommodated on authorized NASA space launch vehicles. Ad hoc space science working groups assisted in selecting and developing the most promising of these experiments for NASA flight missions. Composed of well-known university and NASA scientists appointed by Newell, one group dealt with space radiation, another with magnetic fields and plasmas in space, and the third considered experiments for lunar exploration after Robert Jastrow and Harold Urey convinced Newell of its importance. 14

By the fall of 1959, the Headquarters working groups and Hibbs' scientists at JPL had agreed upon a rough priority of experiments to be carried on the six authorized Vega lunar flights. Since the experiments of sky scientists did not require a precise trajectory, the first two Vega test missions would be instrumented to measure more closely the fields and particles between the earth and the sun. Representations by planetary scientists ensured that the lunar flights to follow would be confined exclusively to investigating the moon rather than the interplanetary medium. This division of available vehicles proved congenial to the interests of both science parties.

In November Hibbs submitted a precis of these deliberations to the JPL Vega Project staff. Planning of the sky science experiments for the first two launches, he informed Cummings and Burke, had reached an advanced stage. Measuring solar corpuscular radiation-the solar atmosphere-and magnetic fields was the objective preferred by these scientists. Second preference had been assigned to investigating the neutral hydrogen cloud that surrounds the earth, third preference to measuring cosmic rays, and fourth, to measuring micrometeorites. Those identified as experimenters were James Van Allen of the State University of Iowa, and others from the Naval Research Laboratory, Goddard Space Flight Center (GSFC), Los Alamos Scientific Laboratory (LASL), JPL, and Caltech. The later lunar rough landing missions would carry the seismometer being developed cooperatively for NASA by Caltech and Columbia University. Additional lunar experiments would be designated in the near future, upon completion of the Vega spacecraft design. 15

But Glennan's cancellation of Vega occurred just as the spacecraft design neared completion. After Silverstein then ordered the five flight Atlas-Agena B Ranger Project, JPL Director Pickering and Vega Program Director Cummings faced a choice: considering only the spacecraft, JPL could begin a new on the design of a less complicated lunar machine for use on the Atlas-Agena; or it could proceed with the planetary craft, building on the work already accomplished. Pickering and Cummings opted for the planetary vehicle. If that course was risky, it nevertheless offered a rapid development of planetary flight technology and experience, nearly on Vega schedules. Besides, the time and money already invested, and the experience accumulated, would be saved. Moreover, if pushed in a concerted fashion, the planetary machine might well return valuable data about the moon in advance of the Soviets. And by using the Vega planetary craft for the lunar missions, NASA could also accomplish the scientific program already agreed upon by the ad hoc working groups at Headquarters and Al Hibbs’ Space Sciences Division at JPL.

On December 28, 1959, representatives of NASA Headquarters met with Pickering and his senior staff to review plans for Ranger. Pickering recommended pursuing the Vega spacecraft and flight mission plans in Project Ranger. The savings in time and money appealed to everyone, and so did the possibility of surpassing the Soviets. 16 Headquarters personnel authorized JPL to proceed in Project Ranger with what had been the Vega planetary spacecraft and flight sequencing. By implication, they also sanctioned Vega's scientific experiments-sky science ventures on the first two Ranger engineering test flights, planetary science on the three lunar rough-landing missions. Newell assured his associates at NASA that the five Ranger missions appeared to be "well thought out from the scientific point of view." 17 Early in 1960 Headquarters officially approved the list of experiments for all five flights (Table II). 18


Ranger test flights

Experiment

Agency and scientist
 Solar corpuscular (plasma) detector  JPL: M.M. Neugebauer, C. W. Snyder
 Photoconductive particle (trapped radiation) detectors  State University of Iowa: J. A. Van Allen
 Rubidium vapor magnetometer  GSFC: J. P. Heppner
 Vehicle charge  Not specified
 Triple-coincidence cosmic ray telescope  University of Chicago: J. A. Simpson
 Cosmic-ray integrating ionization chamber  Caltech/JPL: H. V. Neher, H. R. Anderson
 Lyman alpha scanning telescope (hydrogen geo-corona)  Naval Research Laboratory: T. A. Chubb
 Micrometeorite dust particle detectors  GSFC: W. M. Alexander

Ranger lunar flights

Experiment

Agency and scientist

 Single-axis passive seismometer a  Caltech: Frank Press
      Capsule temperature measurement   Columbia University: M. Ewing
      Maximum deceleration at impact measurement
 Gamma-ray spectrometer b

 U.C.San Diego: J. R. Arnold

 JPL: A. E. Metzger

 LASL: M. A. Van Dilla

 Television camera b   Experimenter Team representing various agencies to be assigned
 a Capsule to survive hard landing.
 b Spacecraft bus - destroyed on impact.

 

Table II. The Original Ranger Space Science Plan


 

Capable of performing sky science experiments and of exploring the distant planets, the Ranger spacecraft would be far more complex than a vehicle designed for lunar missions had to be. The commitment to develop such a machine demanded a major technological advance-from small spin-stabilized earth orbiting vehicles weighing tens of kilograms to a completely attitude-stabilized planetary machine weighing hundreds of kilograms. The first earth satellites had been equipped with small radios to transmit data to stations several hundred kilometers below. The Ranger spacecraft would be able to accomplish tasks automatically in response to a preset program, to process and transmit diagnostic and scientific information, and to receive and respond to commands sent to it from the earth-not just at lunar distances but at interplanetary distances of millions of kilometers. Whether the decision to pin the fortunes of lunar exploration on the development of such a machine within a little more than a year was wise or not, officials at NASA and JPL recognized the task as a high-risk venture-one sure to tax the technology and skills both in and out of the Laboratory in Pasadena.

CREATING THE RANGER MACHINE

On February 1, 1960, Dan Schneiderman issued the design concepts and criteria for the Ranger spacecraft. 19 Since the Vega third-stage vehicle had employed a hexagonal truss and six longerons, the Ranger spacecraft possessed hexagonal symmetry (Figure 21). JPL experience in electronics packaging on the Corporal and Sergeant missiles suggested the use of modular construction of electronic equipment to withstand high levels of vibration. These modules would be packaged in plain rectangular boxes, one bolted to each of the six sides (Figures 22 and 23). Above the 1.5-meter (5-foot) diameter hexagon would rise a "tower" that supported the fixed low-gain antenna and various scientific experiments. Conforming to design concepts that called for tall structures, the tower would become a permanent feature on all early JPL lunar and planetary spacecraft. Below it, two solar panels would be attached to opposite sides of the bus; a 1.2-meter (4 foot) diameter high-gain dish antenna would be stowed directly beneath the spacecraft. Both the solar panels and the dish antenna would be hinged at the frame, designed to swing out from the bus after the spacecraft had been placed on its trajectory in space.


 

Fig. 21. Ranger Spacecraft Preliminary Design



 

Fig. 22. Spacecraft Packaging



 

Fig. 23. Typical Assembly Package


This spacecraft was to be used on the first two test flights, which, with their sky science purpose, were designated Block 1. The three further flights, which would photograph the moon and deposit seismometers on its surface; were designated Block II The three Block II spacecraft would incorporate the midcourse engine and maneuver capability, and a tower to support the seismometer capsule and its retrorocket. Prior Atlas-Agena studies had yielded an estimated weight of 360 kilograms (800 pounds) for the lunar spacecraft, comparable to the weightlifting performance expected of Atlas-Vega.

Systems Division Chief Schurmeier created a Spacecraft Design Specifications Book to guide the JPL design activity and to describe the mission objectives, design philosophy, design restraints (weight, schedule, power, etc.), and functional requirements (what each subsystem was intended to do, and their interactions). NASA, through Cummings and Burke at JPL, would provide project objectives and guidelines; the Systems Division would integrate the complete design and test the assembled spacecraft. Other JPL technical divisions would prepare Ranger's detailed design, procure parts, fabricate components, and test each subsystem. To conserve time and quickly demonstrate the technology for planetary missions, changes in the spacecraft design were to be minimized.

As a surrogate of man in the cosmos, the Ranger spacecraft was to serve a four-fold purpose: first, to deliver its scientific cargo to a celestial target within certain tolerances, then position the experiments, perform the proposed scientific program, and transmit the results back to earth. Priorities for Project Ranger, released by Cummings on February 17, 1960, conformed to this progression. In descending order of importance, he committed JPL to ( 1) develop the spacecraft technology, (2) maintain schedules, (3) establish industrial support for NASA-JPL planetary flight missions, and (4) support science. 20 Although included on the test flights, sky science thus initially held a low position in the scheme of project activities as Cummings and Burke sought to create the technology first, then pursue lunar investigations. In authorizing the eight experiments for the engineering test missions, Silverstein agreed that sky science was not to interfere with the creation of the spacecraft technology. 21

But NASA had specified scientific investigations of the moon as the objective of the Block II Rangers-to acquire more knowledge about our celestial neighbor. 22 Approved in early 1960, the planetary experiments included a television camera to return close-up photographs of the moon, a seismometer to be deposited upon it, and a gamma-ray spectrometer to determine the chemical composition of the surface material. 23 The midcourse trajectory and terminal attitude maneuvers to be incorporated in these spacecraft would position the television camera to take pictures of the moon, and permit release of the seismometer capsule just prior to impact. However, in a compromise between the scientific objective stipulated by Headquarters and the necessity to create the required technology, technology remained the clear emphasis for the engineers charged with Ranger's prosecution. As the project got underway, the priorities established at JPL revealed the essential purpose of all five Ranger flights to be the development of "basic elements of spacecraft technology required for lunar and planetary missions." 24

Under direction of the Systems Division, design of the two test spacecraft moved ahead smoothly, and was completed by May 1960 (Figure 24). 25 To reduce complexity to manageable proportions, the engineers divided the spacecraft system into functional subsystems that corresponded to the responsibilities of the line divisions at the Laboratory. The Telecommunications Division, headed by Eberhardt Rechtin, handled the spacecraft command, telemetry, and communications subsystem; Eugene Giberson and the Guidance Control Division looked after attitude control, power, and central control; GeoMey Robillard's Propulsion Division was responsible for spacecraft pyrotechnic squibs and actuators, and–on Block II-midcourse propulsion; the Engineering Mechanics Division, led by Charles Cole, developed the thermal control, structures, electronics packaging, and cabling for the spacecraft; and Hibbs' Space Sciences Division dealt with the scientific instruments and their control data automation subsystem. Apportioned so that one individual could comprehend an entire subsystem, each one was assigned to a "cognizant engineer" by the respective division chief, the cognizant engineer, in turn, further subdivided the work and guided subsystem development.


 

Fig. 24. Ranger 1 and 2 Spacecraft Design


The tasks to be accomplished by the respective Ranger spacecraft may be seen most readily as a set of increasingly complex phases of operation, as shown in Table III.

 


Mission phases

Blocks

 Launch (spacecraft as passenger) I a II b
 Postlaunch (active period, spacecraft separation, solar panels and dish antenna extended, acquistion of sun and earth) I II
 Cruise (in free fall, orientated to sun and earth) I II
 Midcourse maneuver (active period, attitude change, engine burn, reacquition of sun and earth)   II
 Cruise (as above)   II
 Lunar operations (active period, terminal attitude maneuver, TV, seismometer capsule launch)   II
 a Flights 1 and 2
 b Flights 3, 4 and 5

 

Table III. Progression of Ranger Spacecraft Technology


Ranger had to be designed to operate in free fall and the hard vacuum of outer space. Lacking the protection of the earth's atmosphere, it would be bombarded by radiation from the sun across the entire energy spectrum. Ranger would also demand 100-150 watts of power to operate a host of electronic components. This energy could be supplied continuously by the 1.86 square meters (20 square feet) of solar panels weighing 18 kilograms (40 pounds) or, for up to two days, by a 54-kilogram (120-pound) silver-zinc storage battery. But the electrical power consumed by its onboard instruments would reappear all over the spacecraft in the form of heat that had to be carried away if the instruments were to continue functioning efficiently. After considerable effort, this problem was solved: the final design minimized direct solar energy input and matched it with heat radiated to space without involving any active elements of the spacecraft in this task. Thus, heat levels would be controlled passively-by conduction and radiation-through the use of aluminum and magnesium alloys in the structural elements, by various coatings such as reflective paint and gold plating of electronic boxes, and by carefully distributing heat sources throughout the spacecraft. The electronic boxes themselves were vented so that all equipment operated in the vacuum of space.

Telemetry would determine and record the health of the spacecraft. In all of the subsystems, near-continuous measurements of voltage, current, temperatures, and pressures were to be sampled, channeled through a telemetry coder, and transmitted by radio to receiving stations on earth, where engineers could evaluate the data. But maintaining the health of the spacecraft, so dependent on temperatures, required keeping the vehicle properly oriented in space. That orientation would be determined by information received from photoelectric eyes, and through a working nervous system which included its own electronic brain and gyroscopic sense of balance that directed the motion of the spacecraft by expelling cold nitrogen gas. Especially heavy activity in spacecraft attitude control would occur during initial acquisition of the sun and earth, in the midcourse turns commanded by a central controller with the "muscle" provided by the cold gas jets, and at midcourse motor bum when a special, powerful auto pilot would steady the spacecraft attitude by means of vanes in the rocket exhaust.

For its lunar mission, Ranger's brain would be a miniature central computer and sequencer. This element began as a complex alarm clock on the Block I spacecraft; it was to time and trigger events after launch and enable Ranger to convert from its role as a rocket passenger to that of independent spacecraft (i.e., open the solar panels, activate the solar alignment, and point the dish antenna at the earth). With the midcourse maneuver phase added to refine the lunar trajectory for Block II spacecraft, engineers coupled a computer to the sequencer. Unlike the latter, the computer could receive such numerical information from earth stations as the direction and size of rocket thrust required, then initiate the maneuver on command.

The central computer and sequencer would receive its information from the command subsystem using decoding components in the spacecraft and encoding components on the ground. Other spacecraft activities would also be initiated by communications passed through this system. The radio link was to consist of a powerful transmitter on earth and a very sensitive receiver in Ranger. The same radio system would contain a spacecraft transmitter that conveyed the diagnostic telemetry and scientific experiment data to the earth receivers. Ranger's radio would also operate at radar frequency, and the signal loop-which could carry command, telemetry, and scientific data all at once-would provide accurate two-way doppler tracking at the ground receivers. Before sun acquisition or during the midcourse maneuver, commands to or data from the spacecraft would pass through the low-gain antenna atop the tower; in the stabilized cruise mode and at lunar encounter, the more powerful high-gain dish antenna beneath the spacecraft was to be used. 26

Totaling 270-320 kilograms (600-700 pounds), Block I spacecraft represented a complicated array of interdependent subsystems. The decision to fly scientific experiments on these two engineering test missions precluded adding many redundant or duplicate engineering devices such as a second central controller or attitude control components. The design did include a backup low power transmitter with independent battery power supply; nevertheless, to a greater extent than might have been preferred by its designers at JPL, the craft depended upon successive functioning of unique components in series; that is to say, the proper operation of each subsystem largely determined the operation of its neighbor. A failure in the attitude control or power subsystems, for example, would have adverse effects throughout the spacecraft. To compensate, engineers planned more redundant features for the lunar spacecraft. Among other changes to the bus, they expected to add a second set of attitude control gas jets and a separate gas supply, in addition to the backup low-power transmitter.

Of all the physical changes, a modified tower above the Block II spacecraft was the most noticeable. The JPL-designed hydrazine monopropellant midcourse rocket engine, another addition, would be tucked away out of sight beneath the hexagonal bus. The tower supported the seismometer capsule and its retrorocket; aimed at depositing the seismometer on the moon, the entire assembly was a major subsystem in its own right. Like the spacecraft in inherent complexity, the capsule subsystem had to be designed and developed at the same time as the bus. Short on manpower and facilities, and responding to the wishes expressed at NASA

Headquarters to engage industry in the space program, JPL immediately sought out an industrial firm to design and fabricate this science subsystem. Two weeks after formal NASA approval of Project Ranger in February 1960, three companies received contracts for competitive design studies of the capsule. On April 15 they returned proposals to JPL for evaluation. Ten days later NASA Administrator Glennan announced that the Aeronutronic Division of Ford Motor Company had been selected to build the seismometer subsystem. 27

The Aeronutronic design was novel, its schedule ambitious. The firm proposed to fabricate, assemble, test, and deliver by September 1961 the required number of 134-kilogram (300-pound) capsule subsystems for a cost of $3.6 million. The design mounted the capsule above a solid-propellant retrorocket; a radar altimeter would signal separation and firing, of the capsule's motor at a specified distance above the lunar surface. The full capsule, which was then to separate from the motor, incorporated a crushable outside shell or impact limiter. Inside, a spherical metal survival package floated in fluid to distribute and dampen the structural loads at impact, and to allow erection of the package to local vertical by moon gravity after the capsule came to rest. In addition to tiny batteries, the survival package would contain the single-axis seismometer already being developed by Caltech's Seismological Laboratory and the Lamont-Doherty Geological Observatory at Columbia University. Erection to local vertical on the moon would permit the sensitive axis of the seismometer to be positioned correctly, and allowed deployment of a modest directional transmitting antenna. 28

The Aeronutronic firm appointed Frank G. Denison manager of its Lunar Systems, the group formed to develop the capsule subsystem. A Caltech graduate and former JPL Section Chief, Denison was well known at the Laboratory. He would report to Burke and Kautz in the Ranger Project Office, and to Schurmeier's Systems Division, which would integrate and test the capsule subsystem in the assembled spacecraft. In June, Denison selected and JPL approved the subsidiary contractors to fabricate the major components of the capsule subsystem: Hercules Powder Company, solid-propellant retrorocket; Ryan Aeronautical Company, radar altimeter; and Rohr Aircraft, capsule support structure (Figure 25).


 

Fig. 25. Ranger 3, 4, and 5 Superstructure Design


The Ranger spacecraft design had reached an advanced stage, with the scientific content agreed upon and the principal contractors selected. Before, in the minds of the participants at NASA and JPL, the name Vega had been associated with a launch vehicle. In the months to follow the name "Ranger," besides acting as a project designation, came to apply increasingly to a specific spacecraft genre. Its design concepts and functions had grown from Juno IV in 1958 via Vega in 1959 to become Ranger in 1960. A machine capable of planetary missions appeared destined to inaugurate NASA's program of lunar exploration.


Chapter 2  link to the previous page        link to the next page  Chapter 4

Chapter Three - Notes

The hyphenated numbers in parentheses at the ends of individual citations are catalog numbers of documents on file in the history archives of the JPL library.

1. JPL Interoffice Memo from William Pickering to Daniel Schneiderman-memo is lost-recollection of recipient.

2. See the testimony of Daniel Schneiderman on November 6, 1962, in RA-5 Failure Investigation Board Interviews, October 31-November 6, 1962, p.1 (2-460b).

3. James D. Burke's testimony on November 2, 1962, ibid.; also rationale as described by Clifford 1. Cummings, "The Shape of Tomorrow, Astronautics, Vol. 5, July 1960, pp. 24-25.

4. U.S. Army Ordnance Missile Command, Satellite and Space Program Progress Report for NASA, November 18, 1958 (2-578).

5. See Burke's testimony, RA-5 Failure Investigation Board Interviews (2460b); The Ranger Project: Annual Report for 196](U) (JPL TR 32-241. Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, June 15, 1962), p. 2.

6. JPL Interoffice Memo from John Keyser to Distribution, subject: "Vega Program; Preliminary Design Phase Assignments," April 14, 1959 (21002).

7. Interview of James Burke by Cargill Hall, January 27, 1969, pp. 2-3 (2-1391).

8. Space Programs Summary No. 4 for the period May 15, 1959, to July 15, 1959 (Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, August 1, 1959), p. 7; United States Congress, Senate, Committee on Aeronautical and Space Sciences, NASA Authorization for Fiscal Year 1960, Hearings before the NASA Authorization Subcommittee, 86th Congress, 1st Session, on S. 1582 and H.R. 7007, 1959, Part II: "Program Detail for Fiscal Year 1960," 750; for design evolution see James D. Burke, "The Ranger Spacecraft," Astronautics September 1961, pp. 23-24.

9. JPL Interoffice Memo from William Pickering to Division Chiefs, et al., subject: "Establishment of Space Sciences Division," July 14, 1959 (3- 225); letter from William Pickering to R. L. Bell, Colonel P. H. Seordas, and G. P. Chase, November 20, 1959 (2-865).

10. Burke, "The Ranger Spacecraft," pp. 24-25; the spacecraft functional specifications released in August and September 1959 reflected the decision, see Payload Functional Description, Vega V-6, JPL Functional Design Group, August 21, 1959 (2-945); and James D. Burke, "Design Criteria for Vega Lunar Capsule," December 7, 1959 (2-1349).

11. Homer E. Newell, High Altitude Rocket Research (New York: Academic Press, Inc., 1953), p. v.

12. See the testimony of Homer Newell, United States Congress, House, Committee on Science and Astronautics, 1962 NASA Authorization, Hearings before the Committee and Subcommittees 1, 3, and 4, 87th Congress, 1st Session, on H.R. 3238 and H.R. 6029, 1961, No. 7, Part I, p. 244.

13. Letter from Homer Newell to Bruno Rossi, December 18, 1959 (2-1937); Robert Jastrow, ed., The Exploration of Space, A Symposium of Space Physics, April 29-30, 1959, sponsored by the National Academy of Sciences, the National Aeronautics and Space Administration, and the American Physical Society (New York: The Macmillan Company, 1960).

14. NASA Space Sciences "Staff Conference Report," February 19, 1959, p. 2 (2-1760). See also "From Interest to Resolve" in Chapter One of this volume.

15. JPL Interoffice Memo from Space Sciences Division to Distribution, subject: "Vega Missions, " November 30, 195 9 (2-846).

16. NASA Memorandum for the File from Homer Newell, subject: "Trip Report for the Visit to Jet Propulsion Laboratory on 28 December 1959 by Homer Newell, Jr., Newell Sanders, J. A. Crocker, Morton J. Stoller, December 30, 1959 (2-1935a); letter from William Pickering to Abe Silverstein, December 29, 1959 (2-2483); also William H. Pickering, "Do We Have a Space Program?" Astronautics, January 1960, pp. 83-84.

17. Based on NASA Memo for the File, from Newell, p. 2 (2-1935a). The craft was, nonetheless, represented publicly as a "lunar spacecraft, " Fourth Semiannual Report of the National Aeronautics and Space Administration (Washington: Government Printing Office, 1961 ), p. 5 7.

18. Letter from William Pickering to Gerhardt Schilling, January 20, 1960 (2-668); letter from Abe Silverstein to William Pickering, January 26, 1960 (2-669); letter from William Pickering to Gerhardt Schilling, May 5, 1960 (2-671); letter from Abe Silverstein to William Pickering, May 23, 1960 (2-1411a).

19. Daniel Schneiderman, et al., Spacecraft Design Criteria and Considerations, General Concepts, Spacecraft S-1 (JPL Section Report No. 29-1. Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, February 1, 1960).

20. JPL Interoffice Memo from Clifford Cummings to all Division Chiefs, subject: "Ranger A Program Guidelines," February 17, 1960 (2-1024).

21. Letter from Abe Silverstein to William Pickering, January 26, 1960 (2- 669); also "Mission Objectives and Design Criteria," in Ranger Spacecraft Design Specification Book, Spec. No. RA12-2 110 (Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, April 19, 1960), p. 2 (2-1094a).

22. The objectives of the original Ranger flights one through five were "(a) to create and test a new spacecraft design whose features can be exploited in the performance of lunar and interplanetary flight missions; and (b) using this spacecraft to perform two classes of scientific experiments: first, a group of measurements dealing with particles, fields and the solar atmosphere within one million miles of the Earth; and second, a group of measurements of lunar characteristics close to and on the surface of the Moon. "Ranger Project Development Plan (Rangers 1-5) (Revision 2. Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, August 1, 1962), p. 1-2.

23. Letter from Silverstein to Pickering, May 23, 1960 (2-141 la).

24. JPL Spec. No. RAI 2-2-110, Ranger Spacecraft Design Specification Book p. 1 (2-1094a).

25. Testimony of Burke, RA-5 Failure Investigation Board Interviews (2-460b); Space Programs Summary No. 3 7-3 for the period March 15, 1960, to May 15,1960 (Pasadena, California: Jet Propulsion Laboratory, California Institute of Technology, 1960), p. 26.

26. Spacecraft technical details can be found in Appendix B.

27. NASA Statement from T. Keith Glennan, subject: "Decision to Negotiate on the Lunar Capsule, " April 27, 1960 (2-320).

28. Aeronutronic, a Division of Ford Motor Company, Design Study of a Lunar Capsule Final Report (Publication No. U-870, Under Contract M48024, April 15, 1960), Volume I: "Design Study" (2-703a).


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