Had the cruelty of fate not intervened, 45 years ago, today—on 16 April 1970—the fifth and sixth humans ever to set foot on another world would twice have walked on the dusty surface of the Moon. Following their launch aboard Apollo 13, and a four-day voyage across 240,000 miles (370,000 km) of cislunar space, Apollo 13 astronauts Jim Lovell and Fred Haise would have boarded the Lunar Module (LM) Aquarius and accomplished humanity’s third piloted landing on our closest celestial neighbor. If near-disaster had not radically altered their mission, Lovell and Haise would have performed two EVAs at a place called Fra Mauro, becoming the first Apollo astronauts to explore a hilly upland lunar site. “It was driven by confidence in the LM capability and steerage,” Haise told the NASA Oral History Project of the site selection, years later, “but also, if you’re going to properly sample the Moon … you had to become more diverse in … where you went to get a proper sampling.”
And Fra Mauro was nothing if not diverse.
The site was named in honor of the 15th-century Venetian cartographer-monk Fra Mauro, who created one of the earliest (and relatively accurate) maps of the Old World. His lunar namesake differed markedly from the relatively flat, open plains (or mare) explored by the Apollo 11 and Apollo 12 astronauts and was considerably more rugged, resembling a low “island” in the Moon’s Ocean of Storms. In the late 1960s, many geologists suspected that the lunar highlands had remained virtually unchanged, geochemically and morphologically, since the Moon formed, around 4.5 billion years ago. By exploring into the older and more heavily cratered lunar highlands, it was hoped that Lovell and Haise would identify some of the oldest rocks on the surface.
Fra Mauro had been extensively photographed from lunar orbit by the Apollo 12 crew in November 1969, and samples returned from the Sea of Tranquility and the Ocean of Storms differed markedly in composition from “ordinary” mare materials, to such an extent that they were believed to have been violently ejected over long distances by vast impacts in the lunar highlands. One obvious example of such an impact was the object which created the 750-mile-wide (1,200 km) Imbrium basin, whose southern rim lay 300 miles (480 km) to the north of Apollo 13’s selected landing site at Fra Mauro. In fact, much of Fra Mauro was thought to be composed of ejecta from this ancient cataclysm. By sampling these foothills, Lovell and Haise might shed significant new light on the composition of the pre-Imbrium lunar crust and help to establish an absolute date for when the impact took place.
Of central importance in the so-called Fra Mauro Formation was Cone Crater, a yawning bowl, spanning 1,000 feet (300 meters), whose impact was believed to have dug deeply into a ridge of Imbrium ejecta. Imagery from NASA’s unmanned Lunar Orbiters had shown its rim to be littered with boulders drawn from deep within the blanket of Imbrium material, and Cone was one of Apollo 13’s key sampling locations. “By strategically sampling up toward the crater, you would be sampling material that at the…outside ray of the crater would be the deepest material,” Haise explained to the NASA Oral History Project. “If it’s due to an impact facet, it ‘inverts’—it’s an inverted flap—so if you’re sampling up a ray, the farther-out stuff is the deepest stuff within the crater. And as you get up near the edge of the crater, you’re sampling literally at the surface.”
Reaching Fra Mauro and Cone Crater involved a novel propellant-conservation plan. Previous Apollo missions had entered near-circular orbits at an altitude of about 70 miles (110 km), after which the LM undocked from the Command and Service Module (CSM) to commence its Powered Descent to the surface. However, on Apollo 13, the spacecraft would enter an elliptical orbit, with a high point of 70 miles (110 km) and a low point of only 9.3 miles (15 km). The result was that LM Aquarius would be effectively relieved of the need to perform a Descent Orbit Insertion (DOI) maneuver, thereby providing Lovell with an extra 15 seconds of hovering time in order to select an appropriate landing spot. During his approach, he would clear the 1,000-feet-wide (300-meter) ridge, into which Cone was embedded, and find a safe patch, somewhere between two groups of craters, nicknamed “Doublet” and “Triplet.”
Had the crippling explosion in one of two oxygen tanks aboard Apollo 13 on the evening of 13 April 1970 not occurred, and had the mission proceeded as intended, the crew would have entered lunar orbit at 7:38 p.m. EDT on 14 April, about 77.5 hours after launch. Almost a full day later, at 5:29 p.m. EDT on the 15th, during Apollo 13’s 12th orbit of the Moon, Lovell and Haise would have undocked LM Aquarius from CSM Odyssey, leaving crewmate Jack Swigert alone in orbit. “A radially-downward Service Module Reaction Control System (RCS) burn of 1 fps (0.3 meters/sec),” it was noted in the Apollo 13 Press Kit, “will place the CSM on an equiperiod orbit with a maximum separation of 2.5 nautical miles (4.6 km).” About an hour later, Swigert would have executed a Circularization Burn to establish Odyssey into an orbit of 52 x 62 nautical miles (96.3 km x 114.8 km). Due to perturbations of the lunar gravitational potential, this orbit was expected to virtually circularize by the time of rendezvous with Aquarius’ returning ascent stage, almost two days hence.
In the meantime, Lovell and Haise would have commenced their Powered Descent during the 14th orbit, braking the LM out of the descent orbit by means of the Descent Engine. “Spacecraft attitude will be windows-up from the Powered Descent Initiation to the end of the braking phase,” it was explained, “so that the LM landing radar data can be integrated continually by the LM guidance computer and better communications can be maintained.” About 7,400 feet (2,250 meters) above the Moon, the braking phase would end and Aquarius would be rotated toward an “upright,” windows-forward, attitude, thereby permitting the crew a view of the landing site. Progressing through the upper (“High Gate”) and lower (“Low Gate”) stages of the approach, Aquarius would initiate a final vertical descent at an altitude of about 100 feet (30 meters), by which point all forward velocity would have been nulled out. According to the Apollo 13 Press Kit, touchdown at Fra Mauro was intended to occur at 9:55 p.m. EDT on 15 April, about 103 hours and 42 minutes after departing Earth. The predicted landing spot was situated 30 miles (48 km) north of the Fra Mauro crater.
Like their immediate predecessors, Apollo 12 astronauts Charles “Pete” Conrad and Al Bean, it was expected that Lovell and Haise would remain on the surface for 33.5 hours and supported a pair of EVAs, each baselined at four hours, although each carried an optional extension to five hours, “if the physical conditions of the astronauts and amount of remaining consumables permit.” Plans for a “rest” period in the immediate aftermath of landing had long since been abandoned, and it was anticipated that Lovell and Haise would be suited up and ready to begin the first of their two EVAs at 2:13 a.m. EDT on 16 April, 45 years ago today.
The first EVA would have been very similar to that of Apollo 12, with Lovell departing Aquarius first and being joined shortly afterwards by Haise. The duo would set up an erectable S-band antenna, about 50 feet (15 meters) from Aquarius, for relaying voice, television, and LM telemetry data to Earth-based stations. “After the antenna is deployed, Haise will climb back into the LM to switch from the LM steerable S-band antenna to the erectable antenna, while Lovell makes final adjustments to the antenna’s alignment,” it was noted by NASA. “Haise will then rejoin Lovell on the lunar surface to set up a United States flag and continue with EVA tasks.”
Core objectives would have encompassed the collection of a “contingency” sample of about 2 pounds (900 grams) of lunar soil, the unveiling of a commemorative plaque on Aquarius’ leg and the deployment of the second Apollo Lunar Surface Experiments Package (ALSEP). The latter, situated about 500 feet (150 meters) from the LM, would have supported five discrete investigations: the instrumented probes of the Heat Flow Experiment (HFE), the Dust Detector, the Charged Particle Lunar Environment Experiment (CPLEE), the Cold Cathode Gauge Ion Instrument of the Lunar Atmosphere Detector (LAD), and the Passive Seismic Experiment (PSE). “These experiments are aimed toward determining the structure and state of the lunar interior, the composition and structure of the lunar surface and processes which modify the lunar surface, and evolutionary sequence leading to the Moon’s present characteristics,” NASA explained. “The Passive Seismic Experiment will become the second point in a lunar seismic ‘net’, begun with the first ALSEP at the Surveyor III landing site of Apollo 12. The two seismometers must continue to operate until the next seismometer is emplaced to complete the three-station set.”
In particular, the HFE would have required Haise to drill a pair of 10-foot-deep (3.3-meter) holes with the Apollo Lunar Surface Drill (ALSD). Meanwhile, Lovell would have busied himself with the assembly of the ALSEP Central Station. The pair would then have headed about a half-mile (800 meters) to the west to begin their first period of scientific exploration, venturing as far as the rim of Star Crater. They would have returned to the LM in a looping elllipse, by way of the Doublet crater group, and Haise would have deployed the Solar Wind Composition Experiment (SWCE). This would have concluded a maximum EVA-1 traverse of 5,000 feet (1,150 meters).
Lovell and Haise’s time outside would be tightly constrained, and the clock would forever work against them. “While on the surface, the crew’s operating radius will be limited by the range provided by the Oxygen Purge System (OPS), the reserve backup for each man’s Portable Life Support System (PLSS) backpack,” it was highlighted. “The OPS supplies 45 minutes of emergency breathing oxygen and suit pressure.” Unlike the crews of the two previous Apollo landing missions, Lovell and Haise’s snow-white suits would have been easily distinguishable, for the Commander’s ensemble was emblazoned for the first time with red stripes around its elbows and knees for identification. “Another modification since Apollo 12 has been the addition of 8-ounce (225-gram) drinking water bags, attached to the inside neck rings of the EVA suits,” NASA noted. “The crewmen can take a sip of water from the 6 x 8-inch (15 x 20 cm) bag through a 1/8-inch (0.3 cm) tube within reach of his mouth.”
Returning back inside Aquarius after a minimum of four hours, and perhaps as long as five hours, the astronauts would have grabbed a bite to eat in the broom-cupboard-sized LM and struggled to catch some sleep. Their second EVA was scheduled to begin at 9:58 p.m. EDT on 16 April, and it would feature the first “real” scientific inspection of the Fra Mauro site. Their EVA-2 traverse was expected to cover 8,700 feet (2,650 meters), of which 4,500 feet (1,370 meters) was the outbound half and 4,200 feet (1,280 meters) was the inbound portion, back toward Aquarius. Two sampling stops on the hilly approach to Cone Crater would have allowed Lovell and Haise to gather rock and soil specimens, potentially from lava flow or Imbrium impact material, and they would have moved slowly uphill to reach the rim of the crater, some 400-600 feet (120-180 meters) above the neighboring terrain.
“Almost the entire second EVA will be devoted to Field Geology Investigations and the collection of documental samples,” it was noted in the Apollo 13 Press Kit. “The sample locations will be carefully photographed before and after sampling. The astronauts will carefully describe the setting from which the sample is collected. In addition to specific tasks, the astronauts will be free to photograph and sample phenomena which they judge to be unusual, significant and interesting. The astronauts are provided with a package of detailed photo maps, which they will use for planning traverses. Photographs will be taken from the LM window. Each feature or family of features will be described, relating to features on the photo maps. Areas and features where photographs should be taken and representative samples collected will be marked on the maps. The crew and their ground support personnel will consider real-time deviation from the nominal plan, based upon an on-the-spot analysis of the actual situation.” Both Lovell and Haise would have carried a Lunar Surface Camera, which comprised a modified 70 mm electric Hasselblad.
The two men would put their geological training to good use in collecting several core tube samples, digging a 2-feet-deep (60 cm) trench to evaluate soil mechanics and gas dynamics and collecting a variety of rock samples. During the return journey to the LM, they would have paused at Flank Crater, dug a trench, gathered samples, and bored a 27-inch (68.5 cm) double core tube into the regolith at Weird Crater, before closing out EVA-2 with a soil mechanics sample. Their samples—of which about 95 pounds (43 kg) were planned to be loaded aboard Aquarius’ ascent stage for the return to lunar orbit—would include “core samples, individual rock samples and fine-grained fragments.” Moreover, Lovell and Haise were expected to use a Lunar Stereo Close-up Camera to image “small geological features that would be destroyed in any attempt to gather them for return to Earth.”
In his NASA Oral History, Haise reflected that he and Lovell and their backups—John Young and Charlie Duke—were the first Apollo crew to be extensively schooled by Dr. Lee Silver of California Institute of Technology, together with scientist-astronaut Jack Schmitt. In the months before launch, the prime and backup crews, Silver and Schmitt journeyed into the Orocopia Mountains of southern California, to develop their skills as lunar field geologists. “We would go through two or three exercises a day, using Polaroids in that timeframe, to record the events, and get debriefs from Lee, and discuss geology around a campfire till like 10 or 11 at night,” Haise remembered. “It was a real fast dose and startup of what was kind of the ritual that followed with many of the ensuing field trips, although it got refined in a higher way with equipment we used and more involvement with the back room people who were going to be there during the mission.”
Their lunar explorations concluded, Lovell and Haise would have lifted off from the Moon at 7:22 a.m. EDT on 17 April 1970, after 33.5 hours on the surface, and docked about 3.5 hours later with an undoubtedly very happy Jack Swigert aboard Odyssey. During their time apart, Swigert would have pursued his own program of Lunar Orbital Science, using a large-format Lunar Topographic Camera (LTC), known as the “Hycon.” It was a huge device, with an 18-inch (45.7-cm) lens that completely filled the window of the command module’s access hatch. Swigert would have acquired numerous high-resolution black-and-white images in overlapping sequences for use as mosaics or single frames. His key surface targets were candidate landing sites for subsequent Apollo missions, including Censorinus, the crater chain of Davy Rille and the Descartes highland site. So important was it that, after the return of Lovell and Haise, the crew were to spend another full day in lunar orbit using the Hycon and their other complement of cameras.
Barreling away from the Moon following the Trans-Earth Injection (TEI) burn at 1:42 p.m. EDT on 18 April, they were scheduled to splash down in the Pacific Ocean at 12:17 p.m. PDT (3:17 p.m. EDT) on the 21st, completing a mission of just over 10 full days. Although the Fra Mauro site was subsequently visited by the Apollo 14 crew in early 1971—thereby illustrating its significance to lunar science—it remains intensely disappointing that Jim Lovell and Fred Haise never had the opportunity to put their training and experience to the test on the Moon’s surface. It is equally disappointing that Jack Swigert lost his chance to perform exceptional lunar science from orbit. “The crewmen of Apollo 13 have spent more than five hours of formal crew training for each hour of the lunar landing mission’s ten-day duration,” NASA explained in the Press Kit. “More than 1,000 hours of training were in the Apollo 13 crew training syllabus over and above the normal preparations for the mission: technical briefings and reviews, pilot meetings and study.” Lovell and Haise also participated in 20 suited walk-throughs of their EVA activities, covering lunar geology and deployment of experiments, including the ALSEP.
Yet it must be borne in mind that, aside from the loss of a valued lunar landing mission, Lovell, Haise, and Swigert returned alive from arguably the most harrowing episode in America’s early exploration of the heavens. Against all the odds, they and a remarkable team of thousands on Earth tackled huge problems and overcame each one to snatch triumph from potential defeat. “The most frightening moment in this whole thing is when the explosion occurred and then—after a little period of time—saw the oxygen escaping and we didn’t have the solutions to get home,” Lovell told the NASA Oral History Project. “We knew we were in deep, deep trouble.”
For Apollo 13, the primary mission was lost, but in a remarkable feat of human ingenuity and courage, the mission morphed into something entirely new and continued. “I always compare this like a game of solitaire,” said Lovell. “You turn up a card, and that’s a crisis. If you can put it someplace, the mission keeps going.”