Authors: Richard Tongue
The planning document for a 'Manned Venus Flyby' outlines a realistic development schedule, with two test missions preceding the Venus launch. The first of these missions was to test the suitability of the spent S-IVB stage for long-duration spaceflight, and would have seen a launch of the complex into Earth orbit, with a duration of up to 28 days. The focus of this mission would have been as an engineering test flight, and would have used the standard Block II CSM.
The second flight would have been more ambitious, and would have tested the same systems in Earth orbit for a duration of a year – the length of the planned flight to Venus. Much equipment specific to the flyby would have been excluded, effectively making it a space station analogous to Skylab, with the first use of the Block III CSM, intended for use over an extended period. This would have focused on both engineering and medical testing, and the opportunity would no doubt have been taken for Earth Observation experiments. (For additional economy, it was suggested that this could use two Saturn IB launches, instead of a single Saturn V.)
Assuming these missions had been successful – and 1972 and 1973-74 suggest themselves as suitable timeframes – then the Venus flyby could launch in 1975. There would be windows of opportunity for additional Apollo missions in this period, in the context of test flights; a test of the Block III CSM could have been used to accomplish a 28-day Lunar Orbital mission, to conduct a complete orbital survey of the moon; this could also have been used to test equipment for the probe flotilla. Another flight under suggestion as part of Apollo Applications was to one of the Earth-Moon Lagrange points, to sample any material trapped at these points and determine its nature; this would have been of similar duration to a standard Apollo flight.
There would certainly have been a series of probes launched to precede man to Venus. An element considered essential was the launch of a Pegasus micrometeorite detector, to evaluate the potential risk of a meteor impact in interplanetary space. A Venus orbital probe would also have been likely, again to determine the nature of Cytherean space in context of protecting a crew. The 'Viking' soft-landers on Mars would be another likely casualty, replaced with similar landings on Venus.
As for the flight itself, the craft would have left Earth on June 4
th
, 1975, as indicated. 115 days would elapse before it made its approach to Venus; during this time a focus on astronomic surveys would have been taken, with the launch of the probe flotilla at pre-designated times. (One possibility would be the launch of some additional probes direct from Earth, still to be monitored from the flyby craft.)
During Venus approach, the craft would have been a hive of activity; the complete focus of the crew would have been on the planet, both on making their own observations with the on-board instruments, and monitoring the results of the probes coming in. Shortly after leaving the planet, rendezvous with any sample return craft would have been accomplished, and then the long flight back to Earth would have begun – 252 days before the crew would load themselves and their samples into the Block III CSM, separate from the craft that had been their home for a year, and return to Earth on June 5
th
, 1976.
The crew of the craft is a matter of conjecture, but it would likely have not been anyone who had flown on the two previous missions. There would have been any number of volunteers for such a flight, which would have carried the standard Apollo crew of three. The commander of the flight would have been an experienced astronauts, possibly one of the CMP from a lunar mission; someone like Dick Gordon, Ken Mattingly, Jack Swigert, or Gene Cernan might have been considered – or even a moonwalker – Pete Conrad might have been a possibility, Al Bean, Fred Haise, or even Dave Scott. The second and third seats would have gone to rookie astronauts – one of them an unflown Group V astronaut such as Jerry Carr or Jack Lousma, the third to one of the scientist-astronauts, though
which
would have been a matter of conjecture.
There were two choices. Those scientist-astronauts specialising in materials and engineering would have been ideal for the earlier test flights, but for the Venus mission, it would either have been a medical scientist, such as Joe Kerwin or F. Story Musgrove, or an astronomer, such as Curt Michel. While there would have been a bias towards the first scientist-astronaut selection, the final decision would depend on the astronauts flown on previous missions. A repeat mission is regrettably far less likely. It is unclear what would have been accomplished by flying the mission for a second time, and there would have been requirements for increased radiation shielding for a flight in, say, 1977.
One potential follow-up mission could have been to a near-Earth asteroid; as early as 1966, there were some proposals to send an Apollo-derived complex to intercept the asteroid Eros on a 527-day flight, with a flight complex not dissimilar to that projected for the Manned Venus mission; solar radiation would have been a concern, but as the flight would have been out towards the orbit of Mars, less of a concern than for a repeat of the Venus flight. A Mars flyby might also have been a possibility, but would have required improvements to the Saturn V if it was to be a one-launch mission.
But would
this
mission have ever actually been flown? More to the point,
could
it have been flown? In terms of booster technology, then certainly. The Saturn V could have thrown the flyby complex into the required trajectory without any modifications – the velocity required for a flight to Venus is no greater than that required to reach the moon, it just takes somewhat longer to get there! The Apollo CSM could have been modified to suit the requirements for re-entry at interplanetary speeds, there were numerous studies demonstrating this potential.
The problematic point would have been maintaining the life-support environment for an entire year, but this is not quite so far-fetched as it sounds. Skylab maintained a crew for periods of 28, 56 and 84 days, with the option for an additional 20 days – 188 days in total, half-way there. Given that there would have been a pair of test-flights from which much could be learned in the fields of atmospheric and water recycling and limiting atmospheric leakage, constructing a flyby module with the capability of sustaining a crew for 367 days was probably a realistic goal for 1975.
The biggest question mark would have been the health of the crew, and it would have been here that the second test-flight would have been absolutely essential. Until the Skylab program, the longest duration of an American space flight was recorded by Gemini 6, fourteen days. There were many unknowns in the period over the effects of prolonged spaceflight on an astronaut. Based on thirty years of data, we know
now
that given the proper exercise regime, it is possible for a man to survive for this period – there are several cosmonauts who have lived in space for longer than the duration of the Venus flyby mission. The question was – even if the test had been successful, would NASA have taken the risk?
The mission was probably flyable, albeit with a considerably higher risk factor than the Apollo lunar landings. It
could
have been accomplished, in the 1975 window, had the project begun in 1967 ( gutting the Apollo program in the process, most likely!) The scientific return would have been another question.
Undoubtedly a great deal of medical and astronomical data would have been returned from the Venus mission – but the returned data would have been little different from that returned from a year-long space station flight. As for the primary object of the mission, the Venus flyby – again, it is certain that a good deal of data would have been gathered from the flight, but the bulk of it would have been gathered from the unmanned probes being operated from the flyer. The same effect could have been gathered by unmanned probes over an extended period, as indeed was the case with the Soviet
Venera
and
Vega
probes. The difference would have been that the data would have been gathered in one grand, glorious moment, rather than spread out over twenty or thirty years.
The greatest effect would have undoubtedly been on the shape of the space programs of the USA and USSR over the next thirty years. If the USA had flown to Venus, then there would have been far greater motivation for the USSR to attempt a Mars flyby at some point in the 1980s. The pressure on NASA for more planetary missions would have been stronger, and the government might have been more favourably inclined towards future flights.
And yet...we haven't gone back to the moon. Would we have gone back to Venus, or on to Mars? I would like to think so...but I fear not.
As for the present day? Well, plans for planetary flybys fell into abeyance for many years, but lo and behold – as NASA evolved its Constellation plan for a return to the moon, and a potential progression to longer-ranged missions, manned flybys returned to the schedule, at point scheduled for the 2020s, shortly after a planned return to the moon. Now, however, Constellation is dead and buried, and once again, the manned flyby is off the books. Something about this mission seems to draw people...and one day, this mission profile just might be flown.
Bibliography
A Venus lander probe for Manned Flyby Mission
s, P. L. Chandeysson, Bellcomm, Inc., 1968
Alternate Apollo Missions: Liberation Points
, John T. Wheeler, NASA, 1968
Drop Sonde and Photo Sinker probes for a Manned Venus Flyby Mission
, R. N. Kostoff, Bellcomm, Inc., 1968
Experiment Payloads for Manned Encounter Missions to Mars and Venus
, W. B. Thompson and others, Bellcomm Inc., 1968
Experiment Payload for a Manned Venus Encounter Mission – Venus Tracking and Data Orbiter
, M. M. Cutler, Bellcomm, Inc., 1968
Eyes on the Red Planet: Human Mars Mission Planning
, Annie Platoff, NASA, 2001
Humans to Mars: Fifty Years of Mission Planning
, David S. F. Portree, NASA, 2001
Manned Venus Flyby
, M. S. Feldman and others, Bellcomm, Inc., 1967
Manned Venus Flyby Meteorological Balloon System
, G. A. Briggs, E. M., Grenning, Bellcomm, Inc., 1968
Manned Venus Orbiting Mission
, Edward A. Willis, Jr., NASA, 1967
On Mars
, Edward Clinton Ezell and Linda Neuman Ezell, Dover, 2009
Optical Astronomy on a Manned Planetary Flyby Mission
, W. D. Grobman, Bellcomm, Inc., 1968
Preliminary Considerations of Venus Exploration via Manned Flyby
, D. E. Cassidy, C. L. Davis, M. H. Skeer, Bellcomm, Inc., 1967
Preliminary Mission Study of a Single-Launch Manned Venus Flyby with Extended Apollo Hardware
, Jack Funk, James J. Taylor, NASA, 1967
Russian Planetary Exploration: History, Development, Legacy and Prospects
, Brian Harvey, Springer-Praxis, 2007
Conclusion
None of the missions described in this book happened. But all of them
could
have happened, and arguably, some of them
should
have happened. In 1969, we dared to go to the Moon, ventured forth for three years, and left it – so far for good – in 1972. Many of the moonwalkers are dead now, and the remainder are old men. For a sobering thought, within twenty years it is likely that there will be
no-one alive who walked on the Moon
. That's just sad.
Of the five scenarios projected in this book, some of them are obviously less likely to have happened than others. The Project Horizon moonbase was
just
technically feasible with the technology of the day, but it would have required a national effort an order of magnitude greater than the Apollo program. It would have been a grandiose project, to say the least; even if it
had
been built, it is not likely that it would have lasted, unless it was quickly followed by efforts from rival nations.
It is almost good in a sense that Lunar Gemini didn't happen; it would have been an indication that the United States was falling far behind in the race to the Moon, and needed a more improvised mission to meet Kennedy's deadline. Had such a, to coin a phrase, “faster, better, cheaper”, mission been attempted, it would be nice to think that the money saved would have been used in an extended effort in the 1970s, but this seems unlikely; the Moon would have remained a place where humanity touched for only the briefest moment, and still largely unknown. (But could this have proven a spur to later explorations, say in the 1980s or 1990s?)
Given how much time, effort and blood they poured into it, I firmly believe that the Soviet Union
deserved
to walk on the Moon. It would have been a magnificent accomplishment, and a grandiose spectacle – but it was reliant on the taming of the N-1, and it is difficult to see it succeeding without considerably more funding, which was simply unavailable. At the very least, Zond 7 or Zond 8 should have carried a crew around the Moon, as some level of payback for the effort put in. The amazing thing is not that they failed to land on the Moon, but that with the handicaps and challenges facing them, they dared to try at all.
Apollo 18 and Apollo 19 should have been sent to the Moon. Funding was tight, but considerably more money has been spent on storing and preserving this hardware than would have been used for a lunar flight. The scientific payback would have been high, with the landing program finally beginning to develop a level of maturity. Apollo 20 is perhaps a harder sell; cancelling that mission to free up hardware for Skylab was a better decision, and at least the hardware was
used
. There would certainly have been risks, but no greater than those in previous missions.