When most space enthusiasts hear of the name “Voyager,” it’s often and naturally presumed that the topic involves one or both of the two advanced Grand Tour outer-planet flyby probes launched in 1977.
While not the first outer planet flybys (that honor goes to the 1972 Pioneer 10 and 11 spacecraft) the Voyager probes are legendary, even in the fantastic subject of space exploration. One of the two probes, Voyager 2, is the only spacecraft to flyby four planets and is the only earthly visitor of the outermost ice giants Uranus and Neptune.
As of this writing, although frail and weak on power over 40 years after launch, the Voyagers have exited the boundary of our solar system and are providing interesting data on the nature of interstellar space.
But older people might hear the name of Voyager and lament about a 1960s project that was among NASA’s most complex, ambitious and expensive mission concepts, which had nothing to do with the outer planets of Jupiter and Saturn.
The exploration and conquest of the Moon was a national manifest as part of President Kennedy’s rallying cry to put a man on the Moon and return him home. The Kennedy’ administration’s goal of men to the Moon was a nationalistic and technological challenge to the Soviet Union to their then-overwhelming dominance of repeated Soviet space-firsts, from the first Earth satellite in 1957, the first flybys and contact with the surface of the Moon in 1959, and the first human in space in April 1961.
NASA’s resources at the time, while quite abundant financially, were strained by the agency’s overall ambitions.
The agency’s secondary goal, more so for science than national prestige, was beating the Soviets in going anywhere else first in the solar system.
But space travel in the 1960s was, as you know, a new thing.
The most powerful and available US launch vehicle was the adaptable but rather finicky Atlas SM-65 missile and its variants. NASA began to acquire more and more of these former intercontinental ballistic missiles from the US Air Force as the Titan II came online as a faster way to potentially start and finish a nuclear missile-based World War III.
The original Atlas, several magnitudes lower in sophistication and power than its modern namesake flown by United Launch Alliance today, was hardly the most reliable rocket at the time.
While today’s Atlas V has a 100% launch success record, the original SM-65, of a wholly different design, had a terrifying high 65% failure rate by 1963. NASA’s engineers had a challenging time in taming the missile, not only into a launch vehicle that could send probes into space, but also men, as part of the first US human space project, Mercury.
Even once the missile was sufficiently tamed, Atlas SM-65 and its variations, by itself, lacked the power to put more than a small payload into Earth orbit. It needed an upper stage with sufficient energy to push something out to the Moon, at the very least.
Early upper stages such as the Able worked with even less reliability than the Atlas SM-65 itself and were soon discontinued.
Very shortly after its founding in 1958, NASA began planning the Vega, a two to three stage upper stage for Atlas with the capacity to restart itself to get lunar and additional interplanetary probes where they needed to go.
However, the US Air Force had already started a similar upper stage project to meet their military objectives. To allow their early spy satellite camera systems such as CORONA (disguised publicly under the name DISCOVERER) to fly, the Agena upper stage for Atlas was being developed at the same time as Vega.
When NASA heard about the Agena’s abilities and that the USAF upper stage was already designed for restarts, Vega was considered redundant and cancelled by 1959.
Adapting the Agena with the Atlas vehicle, NASA gained their first interplanetary success with humanity’s first-ever flyby of a planet, Venus, by Mariner 2 in 1962. Fresh with this success, NASA’s attention, and its scientists’ ambition, turned to two other worlds.
Additionally, a variant of Agena was to be put into a parking orbit as a target for the second phase of NASA’s human spaceflight development, Gemini, to encounter the stage in orbit to verify that men could perform rendezvous and docking, vital to the success of the finalized Apollo lunar orbit rendezvous mode of completing a lunar landing mission.
While Agena had a very good success record in military applications, NASA-specific missions, particularly Gemini’s Agena Target Vehicle variant, weren’t as rosy. The mission of Gemini 6 was to be the first rendezvous attempt but its Agena, launched hours before the scheduled Gemini launch, apparently exploded shortly after igniting its hypergolic engine to complete orbital insertion. Another GATV failed to reach orbit for Gemini 9 and another partially failed while in orbit as part of other mission objectives for the last Gemini mission.
Hopes for more complex and heavier space probes rested on development of the Centaur, a far more capable and powerful Atlas upper stage than Agena. But its development was very problematic, unavailable for operational use until 1966.
Getting to the next planetary target, Mars, was the next challenge. The Mariner-Mars probe design itself, because of the payload limits of Atlas-Agena, had to be as lightweight as possible–no easy feat.
Mariners needed complex propulsion, navigation, power and communication systems in a time where computers were something that were no smaller than a large room, a worldwide infrastructure for long-distance communication from Earth to Mars was almost non-existent, and generating electrical power with the newer, heavy inefficient solar photovoltaic cell technologies added more weight.
Atlas-Agena delivered many probes more often than not to Mars, starting with Mariner 4’s historic first of an operational Mars flyby.
Yet four years before Mariner 4 even flew, two agencies in NASA began dreaming big . Really, really big.
Long-range plans by the agency to send probes to the Moon, Venus and even Mars were in work by 1960. National zeal to beat the Soviet Union to various destinations in space meant greater funding for space projects, in potential.
The Jet Propulsion Laboratory had an ambitious plan to send a lander or impact probe to the surface of Mars. The idea also manifested at NASA Headquarters, and heads began to butt as to who was to spearhead design and overall management of the concept given the project name, “Voyager.”
So what was this original Voyager spacecraft?
Simply put, Voyager was what the Viking Mars missions turned out to be, but on steroids. Lots of steroids. Not only was this Voyager intended for Mars, but for reaching and dropping probes on the surface of Venus.
This Voyager project’s doom would be ultimately sealed by something we, today, take for granted when watching NASA develop a new space probe.
In 1960, a space probe management hierarchy we see often today by JPL or other contractors or scientific agency, starting with a project manager or principal investigator with sub-groups of scientists and engineers for instruments, spacecraft and testing, simply didn’t exist.
JPL wanted to own the whole idea of Mariner and Voyager, while NASA wanted more managerial control. It should be noted that JPL, a body that existed before NASA itself, was affiliated with NASA but not always “taking orders” as a department of the University of Caltech.
Because of the chaotic independence of JPL and NASA management in who-led-what and what would fly, there was also competing ideas and concepts to Voyager within the greenlighted Mariner project team itself. Three other Mariner vehicles were initially proposed.
The second, the Mariner-B design, to fly after a Mariner-A mission flyby-only spacecraft, would drop a probe into the atmosphere as it flew by to gather more data of the planet. A Mariner-C type would be an orbiter.
Complicating both Mariner-B and Voyager ideas, JPL was working with educational and presumptive data about Mars and Venus at the time.
In the early 1960s, scientists believed that both Mars and Venus had sufficient atmosphere densities to allow parachutes and heat shielding available to soft-land their probes safely. Their sources of data were biased with notions from science fiction as well as conjecture. Voyager’s idea coalesced long before the first Mariner flybys of the two planets in question.
Voyager proponents saw the Mariner missions to Venus and Mars as pathfinders that would provide sufficient data for designing Voyager probes to reach planetary orbits, and release probes that would enter a planet’s atmosphere, at the very least.
Mostly due to the payload limitations of the only available interplanetary launch vehicle between 1962 to 1966, the Atlas-Agena, the Mariner-B idea was just too heavy to consider seriously. Its lander probe idea seemingly merged with Voyager, losing its name and identity as 1962 passed. JPL’s Voyager supporters wanted to go far bigger than Mariner-B’s small entry probe, after one or two Mariner-A flybys of the two planets.
Voyager was going to be a beast of a space probe, even by today’s standards. The age of miniaturized electronics was just arriving. And younger still was an understanding of how electronics would behave or survive in the extremes of space.
NASA asked for contractor proposals for initial designs of the orbiter and lander. AVCO and General Electric won a preliminary study contract, with designs of large orbiter/lander spacecraft.
AVCO apparently had two designs. A 1963 version didn’t seem to have an specific lander capsule.
Another diagram shows why the design wasn’t intuitive to today’s understanding of Mars aeroshells. A lander would’ve rested inside a rather tall aeroshell.
The second AVCO version was based on the Mariner spacecraft bus which, much later, would bear a more significant resemblance to what would fly in Voyager’s place over a decade after the project’s inception.
But it appeared that the TRW design of 1965 had gained greater attention. Its appearance seemed anything but slim, small or delicate.
The GE spacecraft design was a large, round orbiter bus, with a lander atop inside a massive aeroshell fairing, which varied in height and width based on lander concepts in flux.
Boeing submitted at least two spacecraft buses to carry a similarly immense and non-descript lander and aeroshell (designed by someone else) as with GE’s design.
AVCOs lander used a series of petals that up-righted the probe after touchdown. It was an idea not much different, as it turned out, than the first probe to eventually soft-land (but not operate long) on the red planet: The Soviet’s Mars 3 in 1971.
GE’s landers were little more than simple crasher probes which parachuted to the surface.
Some in JPL considered their own lander design, a tripod look not too dissimilar from the Surveyor lunar landers, with retrorocket propulsion.
Voyager’s general weight (not necessarily including any planetary atmospheric probe or lander) was estimated to be around 2700 to 3175 kilograms (6999 pounds), depending on what orbiter/cruise stage or lander you considered.
If you’re confused by the Voyager concepts shown thus far, you should be.
The studies and concepts presented were so varied in size, weight, lander type and cruise stage (bus) that it is no wonder why the project was in jeopardy the moment it was started.
There were just so many, many ideas. Perhaps too many.
Neither scientists and management didn’t appear to be sticking to any one design path for the spacecraft, lander, or launch vehicle as time passed.
The chaos of proposals and their specifications clearly showed that the early Atlas-Centaur, even once operational by 1966, wasn’t going to cut it with an initial payload maximum weight of around 3700 pounds to Earth orbit.
So JPL and NASA Headquarters considered their new launch vehicle under development: The Saturn.
While today we know of three Saturn launch vehicles, particularly the Saturn V Moon rocket, when the name “Saturn” was mentioned only the vehicle we know as the Saturn I was being initially discussed for space probes by the early 1960s as the project was getting fleshed out.
Saturn was a game-changing launch vehicle, specially built for NASA, not an adaptation of a missile, with potential for many variations to fit space probe needs.
The Uprated Saturn, or Saturn I-B, was a natural choice.
The original Saturn I concept had a three-stage design: The S-I booster stage, an S-IV second stage, and a Centaur upper stage known early as the S-V. While the S-V/Centaur was dropped during early Saturn I development, that Centaur upper stage could still be adapted for Saturn I-B and its more powerful S-IV-B second stage.
Getting any Saturn vehicle reserved for uncrewed space probes, despite its awesome capacity for payload mass, was the real problem. Clearly, Saturn vehicles were far more expensive.
Complicating matters, Saturn I-B production was halted by the mid-1960s, as designs for the vehicle’s keystone payload, the Apollo spacecraft, soon exceeded the ability of the Saturn I-B for Earth orbit tests and thus fewer Saturn I-Bs were needed.
The Saturn V was then considered. But rather than launching a single Voyager, two or more probes would piggyback atop the mighty launch vehicle to take advantage of the vehicle’s colossal payload mass and vehicle expense.
Today’s hindsight shows that a Voyager-Saturn V vehicle’s appearance would bear a notable resemblance to the final Saturn V to launch. and the only Saturn V to fly without an Apollo Command/Service Module: The May 1973 Skylab space station launch. Rather than an Apollo spacecraft stack, a long massive fairing sat atop the S-IV-B for shrouding the probes.
But additional studies thought more probes would be better, given the heavy-lift capacities of the Saturn V. So six and even twelve-probe carriers were considered.
This idea of a massive multiprobe project is more common today with terrestrial smallsat and constellation launches, but virtually unheard of in the mid-1960s, and certainly not for Mars.
The landers themselves, at least in one Boeing study, would be similar to what the Soviets had tried to send in their 1970s attempts in some ways. The simple landers would impact and then fold out out a communications antenna, perhaps a solar panel and an instrument arm.
By the time a Saturn V was considered to hurl boatloads of Voyager probes towards Mars in 1967, fiscal and national priorities began to assert themselves against the Voyagers ever flying. In this, Skylab’s origins with the Apollo Applications Project and this Voyager shared something in common.
Victory was near for Apollo by 1967. NASA’s management saw their overall support for the program fade, starting in their budget. Money was still allocated but voices from Capital Hill were less enthused with further increases. In fact, the funding numbers began to drop.
While Apollo planned for landing missions from 11 through 20, it was by 1967 that orders were given to the contractors to cease further construction on Saturn V stages. Ultimately, no Saturn vehicle would be available for Voyager to use, especially since NASA reserved the remaining Saturns for the only Apollo Applications project to survive the cutting block, and at the price of cancelling three lunar landing missions.
Critically bad for Voyager was that the data from the Mariner 4 1965 flyby revealed that Mars’ atmosphere was far, far more tenuous than expected. It would not support the heavy atmospheric probes of the types Voyager scientists initially envisioned. Thoughts of a lander, and the many studies that proposed the designs, began to seem impossible to implement. More revisions and concepts appeared.
All of these changes in planetary data and budgets left plans for a 1971 Voyager launch scrapped. Scientists shifted to a 1973 Mars launch window, but the Oval Office’s 1967 budget gave Voyager a much more meager level of funding to toy with that idea. NASA redirected focus to more Mariner-Mars missions with the 1969 launch window.
Voyager/Mars would die an agonizingly slow death through the remainder of 1967. You could consider it a casualty of war.
The Space Race was a friendlier aspect of the Cold War between the Soviet Union. But America was taxed in fighting more than one war. The US and USSR were also funding a real war by proxies on Vietnam–and the US was losing that fight. More money was grudgingly added to that armed conflict while President Johnson was forced to reduce some funding to the space program.
When the lunar landings began by 1969, Voyager was quite dead from a thousand little budget cuts. Or so it seemed.
NASA did not give up on the dream of Voyager’s orbiter/lander idea.
The idea simply required some downsizing and modernizing to make it affordable.
Technologies had grown substantially by the early 1970s, creating more capable, reliable, lightweight computers and scientific instruments, with lower power needs.
Mariner spacecraft had become advanced and mature enough to attempt to orbit Mars for greater study, with Mariner 9 becoming NASA’s first Mars orbiter. The Atlas Centaur itself was still too weak to fly even a lightweight orbiter/lander, but there was the newer Titan III-Centaur design to bridge that gap.
The ghost of Voyager sent echoes into a new project, run through NASA/Langley, that considered the factors that ultimately killed the original: Budget, planetary information, and launch vehicle. An improved mission management hierarchy, lead by men such as James Martin, aided the new project greatly.
Enter Project Viking. These vehicles completed what Voyager/Mars would not.
Viking took a heavily adapted Mariner spacecraft bus as its orbiter with a new Surveyor-styled lander, powered by RTGs, but designed in a coordinated manner to land safely based on Mariner 8/9 planetary studies. In fact, the data from Mariner 9 was critical in redefining the Viking lander aeroshell and heat shield, parachutes and lander retrorocket design from any Voyager concepts.
Because of greater mission management and scientific data, Viking’s entry, descent and landing features remain NASA’s standard for EDL vehicles, applied to every lander sent by NASA since 1975.
Only one Mars lander has failed in NASA’s history. Officially, the Mars Polar Lander never regained communications with Earth due to poor vibration testing on the spacecraft after lander separation for powered descent, which may have crashed the lander. Speculation also supported the probability that the spacecraft’s cruise stage never separated during the entry phase, and the vehicle died from aerodynamic forces.
While the Voyager Mars/Venus super-probes would be stillborn, the name itself would not die, of course.
A rare alignment of the outer planets became a very inviting target for the first-ever flybys of Jupiter, Saturn, Uranus and Neptune by the early 1970s. New President Nixon, already juggling what little budget would be allocated for NASA for space probes but also a next-generation human spaceplane, was persuaded by NASA to allocate some funding for these “Grand Tour” probes while Apollo was throttled back substantially, cutting additional lunar landings past 17.
Like Voyager under President Johnson, AAP’s many ideas for extended lunar operations were scuttled with the Nixon-era cuts. All that was left from AAP that would fly was a space station, sort of kludged together from the Apollo-Saturn parts that would never leave for the Moon.
The first Grand Tour spacecraft, Pioneer 10 and 11, left in 1972 to reach Jupiter and Saturn by 1974 to amaze both scientists and the public. The Pioneer name was then retired.
The Mariner probe history itself would end with a 1974 mission to make the first-ever encounter of the innermost planet, Mercury, as Mariner 10.
Two other probes, originally the last of the Mariner program, were branched off, and given the Voyager name for a more comprehensive second wave of Grand Tour spacecraft.
The Voyager 1 and 2 outer planet missions hold little of its early name’s design and purpose, yet forged its own unforgettable achievements worthy of the name, which have yet to be duplicated in terms of scale.
Sources include:
- On Mars: Exploration of the Red Planet. 1958-1978, (NASA publication)
- Voyager design studies, Volume I- Summary (NASA NTRS)
- Voyager design studies, Volume IV- Orbiter- Bus Design, Part 1 (NASA NTRS)
- Voyager Spacecraft System Study, Phase II – Saturn V launch vehicle, Volume I – Summary Final report (NASA NTRS)
- Voyager spacecraft. Volume IV – Alternate designs, systems considerations – Appendices Study report, phase IA (NASA NTRS)
- The First Voyager (1967), WIRED Magazine, Portree, David S.F.
- Saturn I-B/Centaur illustration, Heroic Relics.
Spaceflight Blunders & Greatness 
Fascinating article, but a typo has slipped in: Gagarin flew in 1961, not 1962.
LikeLike
Absolutely right. Writing this article about a train wreck of a project made proofreading a nightmare. Correcting, thank you.
LikeLike