NASA’s Planetary Joint Motion Group Piloted Mars Flyby Examine (1966)

The piloted Mars/Venus flyby idea — the hallmark of which was a Solar-centered trajectory intersecting a number of planets and starting and ending at Earth — was first proposed by Gaetano Crocco in 1956, at a time when robotic probes to different worlds had been scarcely talked about by champions of spaceflight. A decade later, when NASA carried out its first high-level NASA-wide research of the piloted flyby idea, that state of affairs had modified markedly — thanks largely to a 261-kilogram (575-pound) spacecraft referred to as Mariner IV.

Launched on 28 November 1964, Mariner IV demonstrated for the primary time {that a} robotic spacecraft might return helpful knowledge from the neighborhood of Mars. The success of Mariner IV — it captured 21 pictures of the planet because it flew previous on 15 July 1965, and slowly transmitted them to Earth over the next month — gave ammunition to those that referred to as into query the utility of piloted flybys. 

The Mariner IV pictures revealed a cratered, arid floor, and its radio occultation experiment discovered an environment just one% as dense as Earth’s. Mars, seemingly so promising for the event of life, out of the blue appeared virtually as inhospitable as Earth’s barren Moon. 

Supporters of Mars exploration had been fast to level out, nevertheless, that the little spacecraft had imaged solely about 1% of Mars at a decision so low that, had it flown previous Earth, it might not have discovered life. NASA and the planetary science group endured with plans to launch new scientific exploration missions to Mars within the Mariner and Voyager applications (the latter to not be confused with the late Seventies Voyager initially referred to as Mariner Jupiter-Saturn — please see “Extra Info,” beneath). 

Cratered planet: One of many sharpest Mariner IV pictures of Mars. Picture credit score: NASA.

In like trend, piloted flyby proponents — such because the contributors within the Planetary Joint Motion Group (JAG), led by Edward Z. Grey of the NASA Headquarters Workplace Manned House Flight (OMSF) — proceeded with their planning conferences regardless of Mariner IV’s achievement. The primary Planetary JAG assembly, held on the NASA Manned Spacecraft Heart (MSC) in Houston, Texas, on 4 Might 1966, gave roughly equal precedence to piloted Mars/Venus flybys and a piloted Mars touchdown mission. 

By the Planetary JAG’s second assembly, held at NASA Headquarters in Washington on 9 June 1966, piloted flybys had assumed primacy. “The article of the hassle,” the Group declared, “is a Mars/Venus Fly-by functionality by [19]75 with a manned Mars touchdown in view.” 

Satirically, given the destructive impact of Mariner IV, a brand new class of robotic probe was largely chargeable for the optimistic change within the piloted flyby idea’s fortunes. The Mars Floor Pattern Returner (MSSR), first mentioned on the NASA Headquarters assembly, would borrow know-how and expertise from Mariner and Voyager. It will journey to Mars on board the piloted flyby spacecraft. After fastidiously trying out and servicing its programs, the crew would launch it a number of days earlier than the flyby. It will attain Mars hours forward of the flyby spacecraft, land, acquire samples of martian air and grime, and launch them into house. 

The astronauts would seize the pattern container minutes after their closest strategy to Mars. They might analyze the pattern in a lab on board the piloted flyby spacecraft inside an hour of its launch from Mars, earlier than any residing issues it contained might perish. 

Greater than 50 engineers from throughout NASA attended the Planetary JAG’s third assembly at NASA Kennedy House Heart (KSC) on 29-30 June 1966. By then, the Group had begun work on a pair of paperwork: a briefing to the high-level managers of the NASA Administration Council and a preliminary Program Growth Plan (PDP). Bellcomm, NASA’s Washington, DC-based planning contractor, supplied the Group with technical help.

The briefing befell a month later — the Council’s response just isn’t recorded, nevertheless it was apparently favorable sufficient for work on the PDP to proceed. The finished PDP, labelled “For Inner Use Solely,” bore the date 3 October 1966. 

Seven years of growth and testing would precede launch of the 1975 mission. The flyby program nested inside a sequence of extant and anticipated NASA applications and missions, which the Planetary JAG said supplied “a sound base for the event of a manned flyby system.” The piloted flyby spacecraft, for instance, can be based mostly on {hardware} and expertise from Apollo and its deliberate follow-on, the Apollo Purposes Program (AAP). Set to start as early as 1968, AAP was envisioned primarily as an Earth-orbital house station program, however was additionally anticipated to incorporate “restricted lunar exploration” past the Apollo baseline.

AAP astronauts would perform progressively longer missions on board Orbital Workshops, attaining a one-year keep in weightlessness in 1970 or 1971. The AAP Orbital Workshop would take the type of a transformed S-IVB stage, which fashioned the second stage of the Saturn IB rocket and the third stage of the Saturn V. A 3rd Orbital Workshop launched in 1972-1973 would check prototype piloted flyby spacecraft subsystems.

Main parts of the Planetary JAG’s piloted flyby spacecraft. A = Propulsion Module (PM) with toroidal propellant tanks and 4 engines; B = Apollo-derived Earth-Entry Module (EEM) with warmth protect tunnel; C = Mission Module (MM) with tunnel to airlock/organic laboratory; D = Experiment Module (EM) with MSSR probe, airlock, telescope, and organic laboratory (probe complement illustrated differs from that described in Planetary JAG PDP); E = deployed high-gain antenna (stowed place additionally proven); F = deployed photo voltaic array.

In the identical timeframe, robotic precursor probes would offer vital knowledge to engineers designing piloted flyby mission programs. A Mariner spacecraft would launch a probe to plumb the martian ambiance in 1971 and probably once more in 1973 and probes would assess the meteoroid inhabitants between the orbit of Venus and the internal fringe of the Asteroid Belt in 1970 or 1971. The previous would support in piloted flyby probe design and the latter may allow diminished piloted flyby spacecraft meteoroid shielding. Weight saved by lowering shielding may allow a heavier scientific payload on board the piloted flyby spacecraft.

Late 1972 would see a check of a Earth Entry Module (EEM) derived from the Apollo Command Module design however able to withstanding Earth-atmosphere reentry on the finish of the piloted flyby mission at as much as 50,000 toes per second — that’s, 14,000 toes per second greater than the utmost deliberate Apollo lunar-return pace. In 1973-1974, 4 astronauts — the quantity deliberate for the piloted flyby spacecraft crew — would rehearse the piloted flyby mission for a yr in low-Earth orbit on board a prototype 180,000-pound (81,650-kilogram) piloted flyby spacecraft. They might journey to Earth orbit and return to Earth in a 51,500-pound (23,350-kilogram) CSM launched with the flyby spacecraft.

The S-IVB stage was the third stage of the Saturn V rocket (proven in silhouette at left) and the second stage of the Saturn IB rocket. It was tapped because the structural foundation of the AAP Orbital Workshop. The Planetary JAG anticipated that three Modified S-IVB phases launched on two-stage Saturn Vs would increase piloted flyby spacecraft out of Earth orbit towards Mars and Venus. Picture credit score: NASA.

The piloted flyby spacecraft and CSM would attain Earth orbit atop a two-stage “Improved” Saturn V rocket, the workhorse launch car of the piloted flyby program. The Improved Saturn V would comprise an S-IC first stage stretched 20 toes (6.6 meters) to carry further propellants for its beefed-up F-1 engines. Along with launching the piloted flyby spacecraft and CSM, it might be used to quickly launch a sequence of three 231,400-pound (105,000-kilogram) Modified S-IVB (MS-IVB) phases which might hyperlink up with the piloted flyby spacecraft in 485-kilometer (300-mile) meeting orbit to kind an Orbital Launch Car (OLV). 

The MS-IVB phases would every comprise 195,800 kilos (88,800 kilograms) of cryogenic liquid hydrogen gasoline and liquid oxygen oxidizer. Even with added insulation, the liquid hydrogen would boil and escape, so the phases must be used inside about 50 hours of launch from NASA KSC to make sure that they might comprise ample gasoline to launch the piloted flyby spacecraft out of Earth orbit on flyby course previous Mars. 

The Planetary JAG envisioned launching the three MS-IVB phases 12 hours aside. To make doable this “salvo” launch marketing campaign, a 3rd Launch Complicated 39 Saturn V launch pad would have to be constructed beside the 2 NASA had already constructed for the Apollo Program. 

Orbital Launch Car (OLV) meeting configurations. Picture credit score: NASA/DSFPortree.

OLV meeting got here in for particular consideration within the Planetary JAG PDP. In 1973, a crew in a CSM launched on a Saturn I-B rocket would dock with the prototype piloted flyby spacecraft after the one-year check crew returned to Earth. Shortly thereafter, NASA would launch two MS-IVB phases in fast succession. The CSM, docked with a particular docking collar on the entrance of the flyby spacecraft, would act as an area tug to push the piloted flyby spacecraft to a rendezvous and docking with the primary MS-IVB in meeting orbit, then would push the piloted flyby spacecraft/MS-IVB mixture to a rendezvous and docking with the second MS-IVB. The phases would then separate from the prototype flyby spacecraft and ignite in succession to hold out an MS-IVB flight check. The CSM crew would undock from the docking collar and return to Earth.

A full-up OLV meeting rehearsal involving a crew in a CSM, the piloted flyby spacecraft prototype, and three MS-IVB phases would comply with in mid-1974. The CSM would dock with the docking collar on the entrance of the prototype, push it to a docking with the primary MS-IVB, push the prototype and MS-IVB to a docking with the second MS-IVB, and eventually push the prototype and the 2 MS-IVBs to a docking with the third MS-IVB. 

After docking with the piloted flyby spacecraft prototype, the crew within the CSM would have issue seeing the MS-IVB phases throughout docking maneuvers. The Planetary JAG proposed that strategically positioned TV cameras and a viewscreen within the CSM might improve visibility. As well as, an astronaut with an Astronaut Maneuvering Unit backpack may place himself the place he might see the docking operation and name out instructions to the crew within the CSM.

The Planetary JAG advised that, following CSM separation, the three-stage OLV may launch the piloted flyby spacecraft prototype on an interplanetary trajectory and not using a crew. Alternately, the OLV may increase it right into a excessive Earth orbit the place it might function an area station.

The Planetary JAG assumed that the OLV for the 1975 piloted flyby mission can be prepared for Earth departure on 5 September 1975, on the opening of its month-long launch window. After OLV meeting and previous to Earth departure, the flyby crew within the CSM would undock from the docking collar on the entrance of the piloted flyby spacecraft and redock at an airlock port on its aspect. After coming into the flyby spacecraft’s drum-shaped, two-deck Mission Module (MM), their residence for the subsequent 22 months, they might solid off the CSM and the docking collar. The MS-IVB phases would then ignite, burn to depletion, and separate in succession to start a 130-day Earth-to-Mars switch.

Throughout flight to Mars, the flyby crew would function a 40-inch astronomical telescope virtually repeatedly. The Planetary JAG took pains to emphasize the worth of their analysis program, which would come with multispectral photo voltaic, stellar, planetary, and asteroid observations. Photo voltaic pictures had been anticipated to comprise particulars as small as 95 miles (150 kilometers) throughout. The telescope can be housed when not in use inside the flyby spacecraft’s tightly packed Experiment Module (EM). 

In complete, at launch from Earth the EM would comprise 30,190 kilos (13,690 kilograms) of experimental equipment, together with six robotic probes and the biology lab for analyzing the samples collected by the MSSR probe. Along with the 11,692-pound (5300-kilogram) MSSR, probes would come with a 1290-pound (585-kilogram) Lander for floor images, geology/geophysics, and ambiance research, three 100-pound (45-kilogram) Aerodynamic Drag/Impacter probes, and a ten,130-pound (4600-kilogram) Orbiter for planet-wide mapping images. 

The piloted flyby spacecraft would cross Mars between 23 January and 4 February 1976, the precise date and time relying on the date of Earth departure and magnitude in fact corrections required. Because the flyby spacecraft approached Mars, the crew would spend an rising period of time imaging it utilizing the telescope and relaying the high-resolution pictures to Earth utilizing the 19-foot-diameter (5.8-meter-diameter) radio dish antenna mounted on a stalk hooked up to the EM. The photographs, which might quickly reveal new particulars because the piloted flyby spacecraft closed in on Mars, can be of profound scientific curiosity, however would additionally serve an operational goal: they might be used to pick out targets for the robotic lander probes, which might be launched between 5 and 10 days earlier than piloted flyby spacecraft Mars periapsis (closest strategy to the planet).

The MSSR probe can be the primary of the six probes to be launched. After launch, the MSSR would solid off a two-part organic protect. A rocket motor would then ignite to extend the probe’s pace by about 500 toes (150 meters) per second. The crew would start cautious monitoring the MSSR’s course. Twelve hours earlier than touchdown and about 19 hours forward of piloted flyby spacecraft periapsis, they might command the motor to carry out a ultimate course correction, after which it might be ejected.

The MSSR would enter the martian ambiance and land in pre-dawn darkness about seven hours forward of flyby spacecraft periapsis. Instantly after touchdown it might open like a flower with 4 fats triangular petals. The petals would comprise many of the MSSR’s scientific tools, together with two an identical units of 4 pattern collectors on reverse sides of the lander. The MSSR would picture the touchdown web site utilizing a panoramic digital camera and transmit the pictures instantly to the piloted flyby spacecraft, the place the astronauts would use them to pick out sampling areas. The crew would search to deploy the collectors exterior the zone contaminated by the MSSR’s descent rocket engines. 

Partial cutaway of the MSSR probe after organic shell separation. A = course change rocket motor with toroidal propellant tank; B = pattern container hooked up to prime of ascent car third stage; C = stowed science compartment (one among 4); D = folded touchdown leg (one among 4); E = warmth protect aeroshell; F = toroidal descent stage propellant tank; G = removable warmth protect cap overlaying descent engine bells. Picture credit score: NASA/DSFPortree.

MSSR descent. A = separation from the piloted flyby spacecraft and Mars focusing on course adjustments; the course change rocket motor (1) is then ejected; B = Mars ambiance entry and ejection of the protecting cap (2) overlaying the descent engines shortly earlier than ignition of the descent engine cluster; C = ejection of the aeroshell (3) and descent engine (4) operation. Picture credit score: NASA/DSFPortree.

MSSR after landing on Mars. A = pattern container hooked up to ascent car third stage; B = ascent car with three rocket phases with toroidal tanks (numbered in reverse order of use); C = ascent car protecting cowl/protect defending deployed science compartment throughout ascent car liftoff; D = deployed science compartment; E = descent motor cluster. Picture credit score: NASA/DSFPortree.

The Planetary JAG proposed 4 pattern collectors of various designs within the hope that a minimum of one would efficiently pattern the unknown floor supplies of Mars, plus a single rock drill for amassing subsurface samples and a filter for sampling airborne mud. Of the 4 collectors, three — two with rotating cylinders meant to scrape the floor and a “vacuum cleaner” — assumed a dry and dusty Mars, whereas a fourth — the “sticky string” collector — would serve nicely if Mars turned out to be “cheesy or viscous.” About two kilos (0.9 kilograms) of fabric can be collected. A shade movie digital camera would routinely {photograph} the sampling websites then would switch its movie to the MSSR pattern container. 

In the meantime, the opposite probes would arrive at Mars. The solar-powered Orbiter, with a 200-pound (90-kilogram) digital camera, would use a three-stage liquid-propellant propulsion system to decelerate and seize right into a 185-mile (300-kilometer) near-polar orbit 4 hours earlier than flyby spacecraft periapsis. The Lander would attain Mars two hours earlier than periapsis. An hour after touchdown it might launch a 50-pound (23-kilogram) solid-propellant sounding rocket to an altitude of about 45 miles (70 kilometers). The three Aerodynamic Drag/Impacters would enter the martian ambiance six minutes earlier than periapsis. Their missions would finish after they struck the martian floor.

The three-stage MSSR ascent car would raise off in daylight 11.5 minutes earlier than flyby spacecraft periapsis. Stage 1 would burn out and separate 5.5 minutes later, when the pattern container was about 1540 miles (2480 kilometers) behind the flyby spacecraft. Stage 2 would then burn for 4.5 minutes, closing the space to about 540 miles (870 kilometers). After a pause, Stage 3 would burn for a few minute, inserting the pattern container very close to the piloted flyby spacecraft over the night time aspect of Mars 5 minutes after periapsis. The astronauts would lengthen an arm-mounted docking ring, seize the pattern container and third stage, and swing them to a linkup with a port on the biology lab positioned contained in the EM.

Flyby spacecraft periapsis would happen about 125 miles (200 kilometers) above Mars, at which period the spacecraft can be shifting at about 30,000 toes per second (9140 meters per second). At that altitude, the spacecraft’s telescope would, with motion-compensation slewing, in idea be able to discerning floor options 1.5 toes (0.5 meters) throughout. Throughout the flyby, Mars’s gravity would bend the spacecraft’s course by solely 17°.

The MSSR, Lander, and Orbiter probes would proceed to discover Mars because the piloted flyby spacecraft moved outward previous the planet, at first relaying knowledge at a excessive charge through the flyby spacecraft after which transmitting on to Earth at a decrease charge. The authors of the PDP hoped that they might proceed to return knowledge from Mars for a number of years. 

Assuming Earth departure on 5 September 1975, the flyby crew would wish an extra 537 days to return to Earth. Early in that interval, they might spend a lot of their time inspecting the Mars samples. Later, they might return to their wide-ranging astronomy research. The Planetary JAG advised that they might research 12-mile-wide (19.75-kilometer-wide) asteroid 149 Medusa at a distance of about 20 million miles (32 million kilometers) 170 days after Mars periapsis and 75-mile-wide (120-kilometer-wide) asteroid 156 Xanthippe at a distance of about 14 million miles (22.5 million kilometers) 150 days after that. They could additionally uncover new asteroids and comets.

The flyby spacecraft can be on the alternative aspect of the Solar from the Earth when it reached aphelion at 2.2 occasions the Earth-Solar distance. The Planetary JAG anticipated that knowledge the astronauts collected from their distinctive vantage level may very well be mixed with knowledge collected concurrently on Earth to generate a full Solar portrait for the primary time.

Throughout the lengthy flight, the crew might anticipate to look at many photo voltaic flares. Some can be directed towards the piloted flyby spacecraft. At such occasions, the crew would shelter within the thick-skinned EEM. Toroidal tanks containing PM course-correction propellants and spherical tanks containing MM life help gases and liquids would encompass and supply further radiation shielding for the EEM.

The piloted flyby spacecraft would return to Earth between 18 and 26 July 1977. The 4 astronauts would enter the EEM with the Mars samples and separate from the piloted flyby spacecraft. They might use the hooked up PM to nudge their course towards Earth, then would solid it off. The deserted flyby spacecraft would swing previous Earth and enter photo voltaic orbit; the EEM, in the meantime, would enter Earth’s ambiance at a pace of 49,100 toes per second, decelerate, and descend on parachutes to a land touchdown. Strong-propellant rocket motors would soften landing.

The Planetary JAG envisioned that its sequence of 4 piloted flybys would pave the best way for piloted Mars touchdown and Venus orbital missions utilizing nuclear-thermal rockets. These might start as early as 1980 and may proceed into the Nineteen Nineties, when a Mars outpost is likely to be established.

With the PDP in circulation, planning started for a brand new part of Planetary JAG exercise. Within the minutes of a gathering held on 12 October 1966 at NASA Headquarters, Edward Z. Grey proposed spending $1.7 million of NASA’s $8.45-million advance planning finances on the piloted flyby idea in Fiscal 12 months (FY) 1967. Of this, $250,000 can be spent to organize for launch to U.S. trade of contracts for an MSSR research in FY 1968. 

The tempo of piloted flyby planning picked up in November and December 1966. On 17 November 1966, Grey referred to as an advance planning assembly at NASA Headquarters for six December 1966. In a telex message dated 2 December, he defined that “the aim of continuous exercise within the manned planetary space is to be ready to provoke a flyby mission in FY 1969.” He wrote that “to perform this finish, we have to put together a mission proposal by mid-April 1967, in time for consideration within the FY 1969 finances cycle.” 

The following Planetary JAG assembly was held at NASA MSC on 17 January 1967. Within the early afternoon on 27 January, in response to points raised throughout that assembly, Grey dispatched a telex wherein he referred to as on contributors within the Planetary JAG to handle “smooth areas” within the 3 October 1966 report by mid-April. He referred to as “experiment return from a flyby mission. . .one among its main sights and an space which has obtained many looking questions.” Somewhat greater than 5 hours after Grey despatched out his message, hearth raged by the AS-204/Apollo 1 spacecraft at Cape Kennedy, Florida, killing astronauts Virgil “Gus” Grissom, Edward White, and Roger Chaffee.

Piloted flyby planning turned a casualty of Congressional backlash from the hearth, which generated looking questions for NASA extra urgent and speedy than any related to the piloted flyby mission. Planetary JAG work didn’t, nevertheless, finish instantly. The truth is, in Might 1967, Edward Z. Grey and his deputy Franklin Dixon felt assured sufficient to go public with the piloted flyby mission on the fifth Goddard Memorial Symposium in Washington, DC. They referred to as for the 1975 piloted Mars flyby to be made a proper new begin program in NASA’s FY 1969 finances. 

Grey and Dixon eschewed the time period “flyby,” which had grow to be intently related to robotic probes after Mariner IV, in favor of calling the proposed mission a “retriever” or an “encounter.” No matter it was referred to as, the piloted flyby idea — and, certainly, all NASA planning designed to offer the house company a future past Apollo — was in serious trouble by the summer time of 1967. In September 1967, goaded by a Request For Proposals (RFP) NASA MSC distributed to trade geared toward deciding on contractors for the MSSR research, Congress zeroed out all funding for NASA advance planning in FY 1968. NASA MSC collected RFP responses from trade however awarded no contracts.

In the meantime, the Jet Propulsion Laboratory (JPL), with help from the Illinois Institute of Know-how Analysis Institute (IITRI), accomplished a research of an all-robotic Automated Mars Floor Pattern Return (AMSSR) mission. The small research group had begun work towards their 15 March 1967 report, a direct response to the Planetary JAG’s 3 October 1966 PDP, on 26 October 1966. The group argued that an AMSSR mission based mostly on Voyager know-how and requiring however a single Saturn V launch may very well be less expensive than a piloted flyby with MSSR. It was the primary U.S. research of an robotic Mars Pattern Return (MSR) mission.

If an AMSSR probe ever flew, nevertheless, it might not be derived from Voyager, for that program had come to be seen as an costly foot within the door resulting in an much more costly piloted Mars mission. Congress cancelled Voyager in August 1967, simply earlier than it slashed NASA advance planning funding.

Largely as a result of the Soviet Union had declared that it might discover the Photo voltaic System with robots, U.S. robotic Mars exploration fared higher than did piloted flybys. Negotiations with Congress in September 1967 led to a promise of funding in FY 1969 for a pair of Mariner Mars orbiter missions in 1971 and a pair of reduced-cost Mars lander/orbiter missions in 1973 in a brand new program dubbed Viking. 

Sources

Memorandum, J. West, AD/Chief, Superior Spacecraft Planning to Distribution, “Planetary Exploration Program Examine — request for assessment and feedback on programs parameters,” NASA Manned Spacecraft Heart, 9 Might 1966.

Memorandum, R. Hock, DP/Chief, Superior Packages Workplace (PPR-2) to Distribution, “Minutes of Joint Motion Group Assembly on June 29 and 30, 1966,” NASA Kennedy House Heart, 8 July 1966.

Planetary Exploration Using a Manned Flight System, NASA Workplace of Manned House Flight, 3 October 1966.

Memorandum, MT/Director, Superior Manned Missions Program to NASA George C. Marshall House Heart, NASA Manned Spacecraft Heart, and NASA John F. Kennedy House Heart, “FY 1967 Superior Research Planning,” 27 October 1966.

Telex, Edward Z. Grey, Dir, Superior Manned Missions Program, NASA Workplace of Manned House Flight, to NASA MSFC Huntsville, NASA MSC Houston, and NASA KSC FLA, 2 December 1966.

Telex [Priority], E. Z. Grey, Director Superior Manned Missions Program to NASA MSFC Huntsville ALA, Kennedy House Heart FLA, and MSC Houston TEX, 27 January 1967.

People to Mars: Fifty Years of Mission Planning,1950-2000, NASA SP-2001-4521, Monographs in Aerospace Historical past #21, David S. F. Portree, NASA Headquarters Historical past Workplace, February 2001, pp. 23-32. 

Extra Info