Fwd: The Apollo 10 Mission

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: May 19, 2014 10:02:39 PM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: The Apollo 10 Mission

 

 

AmericaSpace

For a nation that explores

May 16th, 2014 

'Somewhere Important to Go': The Need for Apollo 10 (Part 1)

By Ben Evans

Over the years, many have questioned the need for Apollo 10 and why it could not be retasked to perform a lunar landing. In reality, the mission was critical in clearing up many unknowns before a landing could go ahead. Photo Credit: NASA

In the annals of space history, few dates are more important than July 1969, when Neil Armstrong and Buzz Aldrin took humanity's first steps on the Moon. However, their triumphant landing on the Sea of Tranquillity was by no means guaranteed at the dawn of that momentous year. Following the deaths of three astronauts in a launch pad fire, the Apollo spacecraft did not even undertake its first manned test in Earth orbit until October 1968, yet President John F. Kennedy's goal was met within just nine months. Forty-five years ago this week, the crew of Apollo 10 cleared the final hurdle for the historic landing, bringing their spidery lunar module close to the Moon … and leaving a question on many lips: Why did they not land? In reality, the race with the end of the decade was so close that astronauts Tom Stafford and Gene Cernan might indeed have been the first men to leave their bootprints in ancient lunar dust.

As early as September 1967, NASA outlined a series of seven critical steps, labeled "A" through "G," to enable the first piloted landing on an alien world. First would come unmanned tests of the Apollo spacecraft ("A" and "B"), followed by manned tests of the command and service module ("C") and lunar module ("D") in Earth orbit. Next, an "E" mission would fly into a highly elliptical orbit, with an apogee of 4,000 miles (6,400 km), to demonstrate re-entry systems from close to lunar-return velocities. The "F" voyage—later to become Apollo 10—would then perform a full dress rehearsal in orbit around the Moon and would involve a pair of astronauts descending to within 9 miles (15 km) of the surface, clearing the way for the "G" mission: the landing itself.

Much of this plan changed in August 1968, when the E mission was unofficially cancelled in favour of an audacious new expedition known as "C-prime": a manned flight into lunar orbit, aboard Apollo 8, to be launched in December … a mere four months away. By the time Frank Borman, Jim Lovell, and Bill Anders returned triumphantly from Apollo 8, only a dozen months remained in which to meet Kennedy's challenge. The D mission (Apollo 9) went smoothly in March 1969, but as the weeks wore on Gene Cernan began to wonder if his flight, the F mission, might instead be transformed from a dress rehearsal in lunar orbit into a full-blown landing. Tom Stafford, the commander of Apollo 10, had the same thoughts, but unlike Cernan he was decidedly unhappy about them.

Pictured in November 1968, the crew of Apollo 10 (left to right, Gene Cernan, Tom Stafford, and John Young) might have flown a lunar landing mission if the challenge of meeting John Kennedy's goal had been endangered. Having said this, Stafford felt that the dress rehearsal provided by the F mission was not merely desirable, but critical. Photo Credit: NASA

Early in 1969, George Mueller, NASA's head of the Office of Space Flight, hinted strongly that Apollo 10 might make the first lunar landing, but Stafford expressed many reservations. "Tom was not so adamant about being first on the Moon," wrote Cernan in his autobiography, The Last Man on the Moon. "He never looked at it that way. He wanted to do what was the best thing to do to have a co-ordinated, planned program." Instead of embracing Mueller's suggestion, Stafford replied that if Apollo 10 was retasked to perform the landing, "this flight crew won't be on it." In Stafford's mind, there was simply too much work to be done and too many unknowns remained before such an enormous step could be taken.

The main problem was that Apollo 10's Grumman-built lunar module ("LM-4″) was overweight. Grumman engineers knew that LM-4 was earmarked for either an Earth-orbital or lunar-orbital test flight, rather than a landing, and therefore had not subjected it to their Super Weight Improvement Program. The next lunar module, LM-5, on the other hand, was slated for a first shot at the landing and was significantly lighter. "The option, then, was to postpone Apollo 10 for a couple of months until [LM-5] was ready," wrote Deke Slayton, the head of Flight Crew Operations. "When you added up what we would gain, as opposed to what we would lose, the decision was pretty easy." On 24 March 1969, Apollo Program Manager Sam Phillips made the final announcement: The F mission would fly as planned.

Over the years, speculation has been rife that if Apollo 10 had taken place closer to the end of 1969, "adjustments" could have been made to enable LM-4 to accomplish a landing. A little offloading of fuel to shed weight could have helped, but in reality other problems remained which simply had to be resolved. One of these was the phenomenon of "mass concentrations"—"mascons"—which take the form of large positive gravitational anomalies, caused by excess distributions of mass, on or just beneath the lunar surface. Areas of such concentrations included the enormous impact basins of Imbrium, Serenitatis, Crisium, and Orientale, and the effect of mascons upon satellites could be truly profound, even altering their orbits so dramatically as to cause them to crash.

Four months before launch, LM-4, the lunar module assigned to the F mission, is attached to its Saturn V adaptor. Too heavy to attempt a landing, LM-4 had not been subjected to Grumman's weight reduction program. Photo Credit: NASA

Mascons were first reported in the journal Nature in August 1968 by Jet Propulsion Laboratory (JPL) scientists Paul Muller and William Sjogren, who had studied data from the unmanned Lunar Orbiters. Sometimes, the orbiters diverged from their predicted positions by up to 10 times more than they should have done, and NASA quickly realized the importance of knowing where the mascons were situated and how great an influence they exerted. By the end of the year, using data from three equatorial Lunar Orbiters and two polar ones, it was possible to compile a near-complete gravitational map of the Moon's near side. Apollo 8 did not carry a lunar module, so its ability to investigate the mascons was somewhat limited, leaving Apollo 10 as the only mission to observe how the spidery lander's guidance and navigation systems might perform in this situation.

When Stafford, Cernan, and John Young were named as the crew of Apollo 10 in November 1968, NASA described their mission as encompassing a range of options, "from Earth-orbital operations to a lunar orbit flight". When it became clear that Apollo 8 would perform a flight to the Moon, Apollo 10 began to take shape as either a lunar-orbital voyage or a landing. Early plans called for the lunar module to simply undock and fly in formation with the command and service modules, but trajectory analyst Bill Tindall advocated a more expansive program of tests. He wanted to the lunar module to fly close to the surface—as close as 9 miles (15 km)—to rehearse the approach to the point at which a landing mission would begin its Powered Descent. This would permit an all-up test of the descent engine, the landing radar, and the rendezvous radar. Tindall even proposed a "fire in the hole" ignition of the ascent engine at low altitude to simulate an abortive descent, but on this last point he was overruled, on the grounds that Apollo 10 was already filled with tasks and another would overburden the crew.

Although he would not be landing on the Moon, Cernan remained philosophical. "Our pathfinder role," he wrote, "meant launching aboard a Saturn V, flying a quarter of a million miles in space and leaving John in Moon orbit, while Tom and I took the lander on a sweeping flight near the lunar surface. No one had ever done that before." One of Stafford and Cernan's tasks, during their descent, was to observe the leading candidate landing point for Apollo 11. Known as "Site 2," it lay close to the Moon's equator, about 62 miles (100 km) east of the crater Sabine, in the relatively flat Sea of Tranquillity.

Six weeks before launch, Gene Cernan (left) and Tom Stafford stand side by side at the controls of the lunar module simulator. Their mission into the unknown would bring humanity closer to the Moon than had ever been achieved in history … until the landing itself on Apollo 11. Photo Credit: NASA

Even in the late spring of 1969, riding on the coattails of Apollo 8's success, many wondered why Stafford, Young, and Cernan could simply not take a chance: After traveling all the way to the Moon, with all the necessary hardware in place, why not land? However, others cautioned that the software and procedures needed as the lunar module descended in a precise, sweeping arc, under the thrust of its throttleable descent engine, had still to be verified. Two years earlier, managers decreed that half a dozen different docking modes had to be demonstrated, ahead of a landing. "So far," wrote Deke Slayton in his autobiography Deke, co-authored with Michael Cassutt, "we had demonstrated exactly one." The drive to reach the Moon was already proceeding at break-neck pace and had already been daring accelerated by Apollo 8 and the cancellation of the E mission. To skip another step and attempt a landing so soon was too rash to risk.

One of the lessons carried over from Apollo 9 was the need to impose individual callsigns on the lander and the command and service modules. The choice of "Gumdrop" and "Spider" by the Apollo 9 crew went down like a lead balloon with some NASA managers … until Stafford's men revealed their selection: "Charlie Brown" for the command and service module and "Snoopy" for the lander! It was not just a bit of fun. For years, NASA had awarded "Snoopy pins" to its staff in recognition of their outstanding work. "The choice of Snoopy was a way of acknowledging the contributions of the hundreds of thousands of people who got us there," wrote Tom Stafford in his autobiography. "Once you had Snoopy, Charlie Brown couldn't be far away."

In one of the most awe-inspiring sights of the Sixties, the Saturn V, the largest and most powerful rocket ever brought to operational status in human history, rumbles toward Pad 39B. Photo Credit: NASA

Originally scheduled to fly on 1 May 1969, Apollo 10 slipped until the 17th in order to best "fit" the lunar launch window and allow additional training time for the astronauts. Another 24-hour delay was effected to allow Stafford and Cernan to benefit from closer levels of sunlight to those Apollo 11 would encounter when they made their low pass over Site 2. The mission would also make history as the Saturn V's first, and only, liftoff from Pad 39B. (However, the pad was kept in reserve throughout the remainder of the lunar program, lest a disaster wipe out its sister, 39A.) In the weeks preceding Apollo 10, the "newness" of 39B was apparent. As Stafford watched his Saturn V roll out in mid-March, he could not help thinking of the many workers still putting finishing touches to the new pad. As the giant rocket arrived at the launch complex, the paint was barely dry on the umbilical tower. …

Training of the prime crew and their backups—Gordon Cooper, Donn Eisele, and Ed Mitchell—was feverish as launch neared. Not until he was placed into pre-flight quarantine, in early May, could Stafford finally appreciate the enormity of the mission he was about to undertake. On the evening of the 16th, the crews had dinner with Vice President Ted Agnew and James McDonnell, founder of the aerospace giant which had built NASA's Mercury and Gemini spacecraft. Late on the following afternoon, driving a little too fast back to the Cape Kennedy crew quarters after seeing his family, Cernan was pulled over by a deputy sheriff.

An absence of papers in his car's glovebox, an iffy-looking military driving licence which, it seemed, never expired and an unlikely-sounding name aroused the officer's suspicions. Fortunately, a timely intervention by launch pad leader Guenter Wendt saved the day. Sharing a quiet "word" with the disbelieving cop, Wendt finally satisfied him that all was well. No, said Wendt, unfortunately "Mr. Kurnin" could not accompany the officer to the police station, because—motioning toward the distant Saturn V—he had somewhere important to go tomorrow. …

 

May 17th, 2014

'We Didn't Know the Questions': The Trials of Apollo 10 (Part 2)

By Ben Evans

 

Snoopy and Charlie Brown were everywhere in days surrounding Apollo 10. Photo Credit: NASA

Snoopy, the little black-and-white dog from the "Peanuts" comic strip, was everywhere in the days and hours leading up to the launch of Apollo 10. Forty-five years ago this week, he had become the mascot for a mission which would clear the final hurdle to accomplishing humanity's first piloted landing on the Moon. At Cape Kennedy, he could be seen wearing his red scarf and astronaut's bubble helmet on sweatshirts, stickers, posters, and buttons. In effect, as man's best friend, it was somewhat fitting that a canine companion should fly with Tom Stafford, John Young, and Gene Cernan … and Cernan was not alone in drawing several uncanny parallels between their voyage and Jules Verne's famous 1865 novel about a cannon-borne journey to the Moon. Both missions launched from Florida, both carried three men, both would land in the Pacific Ocean, and, in Verne's story, the crew included its own canine passenger, "Satellite." Yet the trials that Apollo 10 would face at the Moon dwarfed anything even the mind of Verne himself could have conceived.  

 

On the morning of 18 May 1969, the risk was temporarily set aside in the excitement. Walking down the hall of the Operations and Checkout Building, Stafford spotted one of their crew secretaries, Jamie Flowers, holding an enormous stuffed Snoopy. Stafford patted it on the head, Young swiped at it and Cernan playfully tried to grab it and take it with him. The playfulness ended when they arrived on the gantry of Pad 39B and were overwhelmed by the seriousness of what was about to happen. "The elevator door rattled closed as we rose up," wrote Cernan in his autobiography, The Last Man on the Moon, "higher and higher and we could see clearly through the wide openings of the safety door. Every inch of the way the rocket beside us hummed and vibrated. Glass-like chunks of ice slid away as her cryogenic lifeblood … boiled and bubbled in her guts. She's alive!" At length, the elevator stopped and technicians welcomed them to the "Twelve-Forty-Nine Express," in light-hearted reference to their scheduled 12:49 p.m. EDT liftoff time.

In the distance, on the beaches and roadways of the Cape, hundreds of cars and trucks and camper vans sat bumper-to-bumper. Thousands of spectators primed themselves for the event of 1969 which only one other mission could possibly surpass: the lunar landing flight itself, in July.

It was a few minutes after 10 that Tom Stafford entered the command module, "Charlie Brown," and scrunched himself into the commander's seat on the left side of the cabin. Next, Cernan assumed the right-side seat of the lunar module pilot and, lastly, came John Young in the centre seat as command module pilot. Pad leader Guenter Wendt—who had saved Cernan from an unfortunate episode with a deputy sheriff the day before—wished them good luck, tapped their helmets, and displayed a thumbs-up, before Charlie Brown's hatch was closed and sealed. Stafford, Young, and Cernan would see no other human being for the next eight days.

Gene Cernan (right) and Tom Stafford await insertion into the Apollo 10 command module, Charlie Brown, on launch day. Photo Credit: NASA

Alone now, the men broke out their checklists and began reading data to flight controllers and implementing computer updates. Apollo 10's stabilization and control system was checked, telemetry and radio frequencies were verified, pyrotechnics were armed, internal batteries inspected, the altimeter was updated, and Charlie Brown's reaction control thrusters were pressurised. "No time to think," Cernan later wrote, "just time to do." As launch neared, external power sources were removed and Apollo 10 was transferred onto its internal fuel cells. Stafford's hand controllers were activated and the Saturn V's guidance system assumed control. Nine seconds before liftoff, the astronauts felt, then heard, the fuel valves opening on the giant rocket's S-IC first stage. Then, the five mighty F-1 engines, engorged with propellant, roared to life.

Three miles (5 km) away, the launch commentator counted down the final seconds, amidst a steadily increasing din: "Ignition sequence start … five, four, three, two … all engines running … " Finally, as the Saturn V broke its shackles to Earth and ponderously rose, like Prometheus unchained, came "Launch Commit … Liftoff … We have a liftoff, at forty-nine minutes past the hour!"

Atop a tongue of flame, and issuing an "unearthly howl," the largest and most powerful rocket ever brought to operational status leaves Pad 39B. Said one journalist, the Saturn was "the mechanized triumph of the modern world … our pyramid of the 20th century." Photo Credit: NASA

Queen Fabiola of Belgium was in the VIP bleachers and instinctively grabbed the arm of her husband, King Baudouin, in surprise as the "unearthly howl" of the largest and most powerful rocket ever brought to operational status rolled over them. Even King Hussein of Jordan, who had seen many launches, flinched at the spectacle. Inside the rattling command module, Stafford, Young, and Cernan were buffeted by vibrations which rifled their way, vertically, up through the booster. Years later, Cernan could think of only two words to describe the sensation: "Absolutely scary."

That scariness was balanced by the pure, adrenaline-fed thrill as the Saturn climbed in stately fashion toward the heavens, taking 11 seconds to clear the tower. The ride on the first stage was a smooth, guttural roar, which pitched and rolled them out over the Atlantic Ocean for the first two minutes of the mission. Next came the sharp jolt of the S-II second stage, which almost propelled them head-first into Charlie Brown's instrument panel, and then the first worrisome signs of "pogo" arose. Pogo was an intense, low-frequency longitudinal oscillation, which rippled up through the body of the Saturn, causing it to "bounce" violently, like a giant pogo stick. "The engineers had shaved 20,000 pounds of metal" out of the S-IC, Stafford recalled, "making the booster walls more flexible and more prone to pogo. Also, there was a ground stabilization bar inside the cockpit that connected our crew couches to the rear bulkhead. It was supposed to be removed before launch, but somebody forgot. The bar magnified the pogo!"

Astonishing view of Earth's northern hemisphere as Apollo 10 begins its "climb-out" from the Home Planet's gravitational "well" afer Trans-Lunar Injection. Photo Credit: NASA

The ignition of the Saturn's second stage, the S-II, came with a noticeable wham, which slammed the astronauts back into their seats. "But the pogo stayed with us," Gene Cernan wrote, "worse than ever, as another million pounds of liquid hydrogen and liquid oxygen … burned hot and hard for seven minutes and we accelerated with breathtaking speed." This acceleration was accompanied by disturbing moans and creaks from the rocket, as its metal strained under excessive pogo forces. Stafford, Young, and Cernan could feel the effect, 20 stories beneath them, but could see nothing, for the command module's only uncovered window was directly in front of the commander's face. Said Cernan: "We were, in effect, blind."

That blindness ended when Young pushed the buttons to jettison the Saturn's escape tower and launch shroud. These blew away with a tremendous roar, and the cabin was instantly flooded with sunlight. The violence of the event surprised Cernan, to the extent that he was momentarily convinced that Apollo 10 had been torn loose from the booster. Still, the view was electrifying, as Africa's western shore and the startling azure blue of the Atlantic Ocean, lapping its coastline came into sight. Stafford, Young, and Cernan had crossed the second-largest ocean in the world … in a mere 12 minutes!

Yet they were not quite in orbit. "We got another stomp when the third stage kicked in," wrote Cernan. After the ignition of the S-IVB, the ride turned from an intense rocking and rolling into something he could only describe as being borne along with the grace and style of a Cadillac. Finally, when the S-IVB fell silent, Apollo 10 was in a 118-mile (190-km) "parking" orbit, around Earth, ready to commence its journey to the Moon … but with one question still unanswered: Had the pogo damaged their spacecraft? Flight Director Glynn Lunney and his Black Team of controllers could see nothing amiss in their telemetry, but they had an uneasy feeling that something was not right. Eventually, Lunney voted with the data on his screen, which told him that nothing was wrong. When Apollo 10 picked up communications with the Carnarvon tracking station on Honeysuckle Creek in Australia, the astronauts received a "Go for TLI."

The six-minute Trans-Lunar Injection burn of the S-IVB began at 3:19 p.m. EDT, a little more than four hours into the mission, when the third stage's single J-2 engine came to the life for the second time that day. For three minutes of the burn, all went well. Apollo 10 accelerated briskly toward the velocity it would need to climb out of Earth's gravitational "well" and set course for the Moon. Unfortunately, the velocity was accompanied by some disturbing vibrations through the vehicle. At their worst, these vibrations were so bad that the astronauts could hardly read their instruments.

Pictured in June 1969, these six men, the crews of Apollo 10 and 11, enabled the final steps of President John Kennedy's goal to be taken. Around the table, from the left, are Mike Collins, Buzz Aldrin, Gene Cernan, Tom Stafford, Neil Armstrong, and John Young. Photo Credit: NASA

Tom Stafford kept his gloved hand tightly closed around the controller which would enable him to shut down the S-IVB and abort the mission. "We're getting a little bit of high-frequency vibrations in the cabin," he radioed, calmly. "Nothin' to worry 'bout." It felt like "flutter"—the aeroelastic phenomenon in which aerodynamic forces on an object, together with an aircraft's natural vibration, produce rapid periodic motions—and Stafford was privately fearful that it would necessitate an abort. With six months left to meet President Kennedy's goal, he simply could not bring himself to twist the abort controller. "An abort would leave us in a giant, looping orbit," he later wrote. "There would be no visit to the Moon, no test of the lunar module, just a two-day wait for re-entry." For Stafford, the decision was a no-brainer: he would not call an abort. "If she's gonna blow," he told himself, "she's gonna blow."

On the other side of the cabin, Cernan was thinking of the abort procedures, but also could not bring himself to execute them. Stafford repeatedly whispered, "C'mon, baby." At length, after six minutes, the S-IVB shut down, on time. Apollo 10's velocity was right on the money at the 23,900 mph (38,500 km/h) needed to begin the three-day voyage to the Moon. The scare illustrated a harsh truth: On the United States' second journey beyond Earth orbit, nothing could be taken for granted and everything was still a huge unknown.

Gene Cernan summed up their feelings perfectly in his autobiography. Years of flying the most advanced aircraft on Earth, pushing them to their limits, and finding answers to pre-determined questions now counted for nothing. "Out here," Cernan wrote, "confronting a foreign and hostile environment, where there was no horizon, no up or down, and where speed and time take on new meaning, we not only didn't know the answers … we didn't know the questions!"

 

 

May 18th, 2014

'We Have Arrived': The Marvels of Apollo 10 (Part 3)

By Ben Evans

 

Mission controllers anxiously watch the "transposition and docking" of lunar module Snoopy, four hours into the Apollo 10 mission. Photo Credit: NASA

Four hours after a bone-jarring launch from Cape Kennedy and an equally rattling ride through Trans-Lunar Injection, the crew of Apollo 10 were finally on their way to the Moon on the afternoon of 18 May 1969. Their mission to lunar orbit would clear the final hurdles before humanity's first piloted landing on an alien world on Apollo 11. Those hurdles included astronauts Tom Stafford and Gene Cernan guiding the spider-like lunar module, which they had nicknamed "Snoopy," to within nine miles (15 km) of the surface … and leaving crewmate John Young as the first man ever to fly solo in orbit around the Moon.

Shortly before 4 p.m. EDT on 18 May—45 years ago today—Young executed his first major task of the mission by pulling Apollo 10's command and service module, "Charlie Brown," away from the spent final stage of the Saturn V rocket. He smoothly rotated the craft by 180 degrees in a so-called "transposition and docking" maneuver to collect Snoopy. By now, in the mysterious void between Earth and the Moon—known as "cislunar space"—the view of the Home Planet had changed significantly. In the hours after launch, it resembled a gigantic map, unfolded "beneath" them, but now, as they headed toward the Moon, it had shrunk noticeably, from filling Charlie Brown's windows to something the size of a basketball. By the time they reached lunar orbit, it appeared little bigger than a marble. "For the first and only time in my space flights," Stafford later wrote in his autobiography, We Have Capture, "I felt strange." They were a long way from home.

For Cernan, a man born and raised in the Catholic faith, yet by his own admission "not an overly religious person," it redefined everything he thought he knew; out here, the smallness of Earth, its continents, and even its vast ocean trenches were dwarfed by the true infinity of the Universe. This beautiful, perfect, limitless expanse of nothingness must, he reasoned, prove the reality of some form of Creator, but to comprehend the matter further went beyond his mortal understanding. "Someone, some being, some power, placed our little world, our Sun and our Moon where they are in the dark void," Cernan pondered, "and the scheme defies any attempt at logic."

There can be few views from lunar orbit more electrifying than the sight of "Earthrise," as our Home Planet rises over the Moon's limb. Upon this blue and white marble resides everything that we humans know and understand. Photo Credit: NASA

These thoughts were undoubtedly with all three men at quiet times throughout their voyage, but such were the demands of a lunar expedition that no one had the opportunity to dwell upon them. Notions of infinity came figuratively back to Earth by the grind of daily life aboard ship. Achieving President Kennedy's challenge was on everyone's mind. None of the astronauts wanted to screw up, get sick, or miss a step in the timeline. Sickness was a major concern. All three men had experienced stuffy heads upon arriving in space, although the sensations cleared within a few hours for both Stafford and Young. For Cernan, it lingered a little longer, but by 20 May he felt fine.

It was a little ironic that Apollo 10 was the first American flight in which bread—real bread—officially became part of the crew's pantry. "Officially," that is, because some years earlier one member of Stafford's crew was reprimanded for taking a corned-beef sandwich into space. On the Gemini 3 mission, John Young arranged for the treat to be sneaked aboard as a surprise for his crewmate, Gus Grissom. Unfortunately, after taking a bite, Grissom had been obliged to put it away when it started to crumble and bits began to float around the cabin. This problem was solved in time for Apollo 10: slices of white and rye bread were flushed with nitrogen, which kept them fresh for up to two weeks and prevented them from drying out and crumbling into fragments.

Drinking, on the other hand, gave Tom Stafford a rather unpleasant surprise when he forgot to open a valve to the ship's water tank and was rewarded with an evil-tasting dose of highly chlorinated water. There were other problems, too. The drinking water was a by-product of the hydrogen-oxygen fuel cells, which generated Charlie Brown's electricity, and on previous missions astronauts had complained about the presence of hydrogen bubbles in it. A new drinking bag was created, with a handle that enabled the astronauts to whirl it around and separate the gas from the water. Unfortunately, it did not work and caused the hydrogen bubbles to settle at the bottom, then remixed with the water when they took a sip. All three astronauts suffered what NASA euphemistically referred to as "gas pains," but they avoided an outbreak of diarrhoea.

Demonstrating the smallness of the Apollo command module, this training view of the Apollo 10 crew reveals the cramped conditions of their voyage to the Moon. Photo Credit: NASA

Maybe the quality of the drinking water affected the men's appetites, which remained low throughout the mission. To be fair, the food was by no means haute cuisine: even Don Arabian, head of the Apollo Test Division, who once described himself as "a human garbage can," struggled to find anything appealing in the tasteless sausage patties and minuscule chicken bits. Early in May, he volunteered to try Apollo 10's fayre for four days … but after three days of chewing food with a taste like granulated rubber, he understandably lost the will to live! Some foods were better than others, of course, and some could even be eaten quite "normally" with a spoon; but the dehydrated dishes needed reconstituting with water and that meant injecting an uncomfortable amount of hydrogen gas into their meals. Not surprisingly, the men ate little during their mission to the Moon.

Still, with Snoopy attached to Charlie Brown's nose, Apollo 10 provided a relatively large space in which to live and work. For Tom Stafford, whose two previous Gemini missions had been like sitting in the front seat of a Volkswagen Beetle for days on end, it felt almost like having an attic or an extra apartment. The job of opening up that apartment fell to Gene Cernan, who floated through the tunnel early on 19 May … to be greeted by a snowstorm of floating fiberglass crumbs! It turned out that a Mylar cover on the command module's tunnel wall had torn loose, releasing the cloud of snowy particles, which itched like hell, took hours to vacuum up, stuck to hair, eyebrows, and lashes, and left Cernan looking "like a hound dog who'd been in a chicken coop."

The rugged, forbidding lunar landscape, seen from Apollo 10. Photo Credit: NASA

By the following morning, Apollo 10 was more than 240,000 km from Earth and its velocity had slowed to a relatively puny 2,480 mph (4,000 km/h), as the gravitational influence of the Home Planet waned. Shortly thereafter, it entered the Moon's sphere of gravitational influence and began to accelerate as it "fell" toward its objective. "Our trajectory," wrote Stafford, "had been so accurate that three of our four mid-course correction burns had been cancelled." The only mid-course burn of Charlie Brown's large Service Propulsion System (SPS) engine changed their velocity by barely 33 mph (54 km/h). It was so accurate that the last two burns were canceled. This also served to calibrate the engine for the forthcoming entry into lunar orbit.

Eight and a half thousand miles (14,000 km) from the Moon, they made a television transmission, giving their audience another view of Earth, which by this point had diminished to somewhere between a grapefruit and an orange. Such views gave Stafford a chance to jab at the British Flat Earth Society that "the Earth is round." Perhaps the use of the word "round," rather than "spherical," pre-empted the society president's defiant response: "Colonel Stafford, it may be round, but it's still flat, like a disk!" Yet the television camera was a marvel and gave the eager audience an unprecedented sense of "being there." By the end of the flight, Apollo 10 made 19 telecasts, spanning almost six hours and providing such a novel dimension for what was happening in space that Stafford, Young, and Cernan received a special Emmy award. The resolution was so good that when they filmed the transposition and docking with Snoopy, viewers could actually count the tiny metal rivets on the lunar module's skin. "Finally," wrote Cernan, "the taxpayer would get a look at where their money was going."

If the taxpayer knew where their money was going, it was not until Apollo 10 passed around the limb of the Moon late on the afternoon of 21 May that the astronauts finally saw where they were going. Until then, their goal had been virtually invisible. "During the entire mission," wrote Stafford, "we had been facing its night-time side, which was almost totally black. Peering through his navigation equipment, John Young had been able to find a place in the sky where the stars were occluded, so we were pretty sure the Moon was out there." To this day, Cernan maintains that his first glimpse of the lunar surface was not grey or white … but blue. But this mistaken impression lasted barely a second, before its true greyish-brown hue became apparent. The trajectory planners and mathematicians had guided them to the Moon with pinpoint accuracy and there it was, the lunar surface, just 60 miles (95 km) from them; so close, it seemed, that they could almost touch it. …

Captured from one of Apollo 10′s colour telecasts, this view reveals craters to the west of the Sea of Fertility, on the lunar near side. Photo Credit: NASA

A few minutes before five in the evening, the SPS engine slowed Apollo 10 by 3,660 mph (5,900 km/h) and inserted it into an elliptical orbit. "I pitched the spacecraft over," wrote Tom Stafford, "so we could get a good view of the surface. We were looking at the so-called far side of the Moon, the tide-locked side facing away from Earth." Visible in sharp relief were forbidding mountains, pockmarked ridges and furrows, and thousands of craters—including the gigantic Tsiolkovsky basin, named after the humble Russian schoolmaster today revered as the father of theoretical cosmonautics. Indeed, the lunar far side looked so tortured that it reminded Stafford of a plaster-of-Paris cast.

On the near side, the dark, basalt-rich Sea of Crises was easy to spot, a flat-floored, wrinkle-edged blob, clearly visible to the astronauts in the wonderful, eerie clarity of the early lunar morning. It really stood out, said Young. Stafford added that the ridges running across its floor went "straight down just like the Canyon Diablo in New Mexico." Originally given the Latin name "seas" (mare) by early astronomers, who mistook their darkness for being open water, the lunar mare were actually formed by ancient volcanic eruptions, many of which (as a result of the samples collected by astronauts on the Moon) have been dated to between three and four billion years old. Their intrinsic darkness comes from their iron-richness and some two dozen maria on both the near and far sides cover around 16 percent of the lunar surface.

Two orbits after their arrival, a second SPS burn roughly circularised Apollo 10's path around the Moon at an altitude of a little more than 110 km. As the astronauts gawped through Charlie Brown's windows, their eyes adapted to distinguish finer gradations of colour in this lifeless world. It was now early morning, lunar time, and the surface exuded a vivid spectrum from white to black and a mix of greys, tans, sickly pale yellows, and hints of red in some craters. The spectacle was completed by the awe-inspiring sight of their first Earthrise on the lunar horizon; even at this distance—some 240,000 miles (370,000 km) from home—they could still pick out the ice caps, the vast bulk of Antarctica, the southward-projecting finger of Baja California, the intense flecks of white cloud, and the iridescent blues of the oceans.

Moving into their third orbit around the Moon, Stafford, Young, and Cernan again broke out the camera and treated their audience to the first-ever televised images of Earth's closest celestial neighbour … in color. Although these early images were somewhat "washed-out," thanks to the height of the Sun in the sky, they improved as Apollo 10 headed westward, where the illumination was oblique and the terrain was brought into sharper relief. Capcom Joe Engle in Mission Control described the vast expanse of the Sea of Fertility as "unbelievable." Other controllers were dumbstruck by the Langrenus impact crater, its walls up to two miles (3.2 km) high in places, its central, cone-like peak rising 3,200 feet (1,000 meters) from an irregular, boulder-strewn floor that Apollo 8 astronaut Jim Lovell, the previous December, had described simply as "huge."

Stafford keyed his mike: "Houston, tell the world we have arrived!"

 

 

May 19th, 2014

 

'Weaving Up the Freeway': The Triumph of Apollo 10 (Part 4)

By Ben Evans

One hundred and sixty thousand kilometres from home, this electrifying view of Earth from Apollo 10 reveals many of the lands around the Mediterranean, from whence "Western" civilisation arose. Photo Credit: NASA

Forty-five years ago this week, three astronauts circled the Moon. Their spacecraft had many of the provisions needed to execute a landing—a command and service module, which they had nicknamed "Charlie Brown," and a lunar module, "Snoopy"—but on this "F mission," the crew of Apollo 10 would perform a full dress rehearsal for humanity's first landfall on alien soil. They would test the descent engine, guidance and navigation systems, and radar of the lunar module, would rendezvous high above the Moon, and in doing so would clear the final hurdle in anticipation of the historic Apollo 11 voyage in July. In doing so, however, Tom Stafford, John Young, and Gene Cernan would come face to face with the immense risk that they were taking and would depart the Moon fully aware that the journey was fraught with danger and complexity.

Early on 20 May 1969, Stafford and Cernan shimmied through the short tunnel from Charlie Brown into Snoopy. Their day began with an irritating problem with a radar gauge, then a communications difficulty, and later an error with the lunar module's gyroscopic stabilisation platform. Precisely on schedule, Apollo 10 disappeared behind the Moon on its 12th orbit and, when the radio blackout ended 40 minutes later, Stafford jubilantly announced that Charlie Brown and Snoopy had successfully parted company. After the undocking at 2:00:57 p.m. EDT, Young used his thrusters to withdraw from the lander.

"You'll never know how big this thing gets when there ain't nobody in here but one guy," he drawled.

"You'll never know how small it looks when you're as far away as we are!" countered Cernan.

"Yeah," continued Stafford. "Don't get lonesome out there, John."

As the range opened, it was Young's task to activate a homing receiver for the lander's rendezvous radar, and he had to toggle a switch several times to make it work properly. Then a glitch with the orientation of Snoopy's antennas affected communications with Charlie Brown. Next, the link between Charlie Brown and Houston fell silent. "A quick check of the system," wrote Stafford, "showed that a breakdown had occurred in the line between Houston and the tracking station in Goldstone, California." At length, the problems ironed out. For the next eight hours, Young would score a new record: the first man to fly solo in lunar orbit.

Somewhere behind the Moon, during the first of Snoopy's four independent orbits, Stafford fired the descent engine for the first time to reduce its velocity and begin dropping toward the lunar surface. He started the engine at its minimum thrust level—first 10 percent, waited for a few seconds, then opened the throttle to 40 percent—and, from his vantage point, John Young reported that they were moving noticeably away from him. For the men aboard the lander, on the other hand, the ride seemed relatively slow and established Snoopy in an elliptical orbit with a perilune of 9 miles (15.4 km) above the surface. The two astronauts, broadcasting on "hot-mike" to the whole world, were exultant.

"We is down among 'em, Charlie!" radioed Cernan.

"Rog, I hear you're weaving your way up the freeway," replied fellow astronaut Charlie Duke, the capcom in Mission Control.

Twelve miles (20 km) above the Moon, as intended and precisely on cue, the radar detected the looming surface and began feeding rate-of-descent and altitude data into Snoopy's computer. The lunar mountains, rushing past below, seemed almost close enough to touch, their appearance and texture resembling wet clay. As they approached Mare Tranquillitatis, running along an imaginary "lane" of physiographic features memorised from months of studying maps and charts, the timeless majesty of Earthrise peeked above the horizon. Also astounding was the sheer barrenness of the forbidding terrain. "There are enough boulders around here," Stafford breathed, "to fill up Galveston Bay."

Since their assignment to the mission the previous November, Stafford and Cernan had spent hundreds of hours poring over maps and photographs from the unmanned Lunar Orbiters of two of the candidate landing sites for Apollo 11. Both lay in the relatively flat Tranquillitatis region, and the men had even tried to simulate part of their trajectory aboard a T-38 aircraft back on Earth. When the time came to fly over the favoured landing spot, "Site 2," for real, they knew the craters, mountains, rilles, bumps, hollows, and furrows so well that they literally formed a familiar "road," guiding them toward the landing zone. To their eyes, it was a virtual lunar highway and they had nicknamed it "U.S. 1." Along the way, a range of low mountains was called the "Oklahoma Hills," a rille which split into a pair of craters was dubbed "Diamondback" and "Sidewinder" and one ridge was even named in honour of Stafford's then-wife, Faye.

Hypatia Rille, nicknamed "U.S. 1″ by the Apollo 10 crew, is the snaking, linear feature in the top left of this image, leading toward the Site 2 region in the top right. Photo Credit: NASA

Attempting to shoot a photograph every three seconds as Snoopy passed over Site 2, Stafford was annoyed when the "goddamn" Hasselblad issued an ominous puff of smoke and jammed. (He later apologized to Victor Hasselblad upon his return to Earth.) It was the first of a number of unfortunate outbursts from Snoopy's cabin. Deprived of his camera, Stafford resorted to verbal reports, comparing the inhospitable appearance of the site to the high desert near Edwards Air Force Base in California. If Neil Armstrong and Buzz Aldrin were to find themselves heading for the "near" end of the target ellipse, then they would have a smooth landing; but he advised that a landing at the "far" end would demand additional fuel to find a spot free of boulders. Just beyond Tranquillitatis, and an hour after the first burn, Stafford again fired Snoopy's descent engine, this time using full throttle to accelerate them by almost 125 mph (200 km/h) and enter an eccentric orbit that simulated an ascent from the surface.

When the time came to jettison the descent stage and return to redock with Young, Stafford oriented the vehicle correctly but noted a slight yaw rate on his attitude indicators. "Telemetry suggested we might have an electrical anomaly," he wrote, "so I started to troubleshoot the problem." Shortly thereafter, Cernan, thumbing through his checklist, switched control from the Primary Navigation, Guidance and Control System (PNGS) to the Abort Guidance System (AGS). The former provided an exact navigational reading, whereas the latter would "get us the hell out of there if unexpected trouble cropped up." In case Armstrong and Aldrin needed to abort in a hurry—punching their ascent stage away if their descent went awry—a test of the AGS in lunar orbit was critical. Stafford and Cernan had rehearsed it a hundred times in the simulator. Clad in their bulky suits, however, high above the Moon, both men found it difficult to hit the right switches. An instant after Cernan set the control mode of the AGS to "attitude hold," Stafford reached across and inadvertently changed it to "auto."

Seconds later, they were ready to blow the four explosive bolts to separate the ascent stage from the descent stage and begin to trek back to Charlie Brown. Suddenly, and without warning, Snoopy went berserk, lurching wildly in both pitch and yaw axes. "Gimbal Lock!" shouted Stafford urgently, believing the lander's gyros to have frozen. Then, Cernan, over hot-mike and with the whole world listening in, yelled with unfortunately crystalline clarity: "Son-of-a-bitch! What the hell happened?" As the menacing lunar terrain, the black sky, and the grim line of the horizon alternately flashed in Snoopy's windows, both men knew they had just seconds to resolve whatever was wrong.

By activating the AGS and mistakenly setting it to "auto," Stafford had in effect instructed Snoopy's radar to begin searching for Charlie Brown and the abort guidance system was now causing the lander to flip wildly around its center of mass. Quickly, he pushed the button to jettison the descent stage and steadily regained control of the gyrating ascent stage. Fearing that the inertial measurement unit was close to gimbal lock, Stafford executed a pitch maneuver, started working the attitude switches and finally calmed the ascent stage down. From Cernan's initial shout to Stafford's final report to Houston that Snoopy was back under control, three minutes elapsed. Those minutes were unnerving not only for Stafford and Cernan, but also for John Young, listening helplessly from Charlie Brown. "I don't know what you guys are doing," he drawled in his typically understated manner, "but knock it off. You're scaring me!"

With the descent stage gone and an ascent stage finally under full control, Tom Stafford and Gene Cernan guide Snoopy back toward Charlie Brown. Photo Credit: NASA

Years later, Cernan and Stafford would both say that it was a classic piloting error. "Neither Tom or I can be sure," Cernan related, "but when it came time to stage … there was some switch that had to be changed, and I changed it. And I'd be willing to bet that … I put the switch in the new position and Tom went ahead and moved it back to the old one. His action was to move the switch. I'd already done it for him. But he didn't know that and, when he moved the switch, he just moved it back to where it was. In effect, we created the problem!"

Although the cause of the glitch was easily solvable in time for Apollo 11, the episode highlighted that nothing could be taken for granted on a lunar expedition. Charlie Duke, helpless to assist, had warned them from his data that they were close to gimbal lock, but things were moving far too quickly for him or anyone else in Mission Control to help. By contrast, the return to Charlie Brown was perfect; Stafford found Snoopy's ascent stage a little difficult to hold steady, but Young had no problem docking and all three men were greeted by the welcome "ripple-bang" of a dozen capture latches snapping shut. "Snoopy and Charlie Brown are hugging each other," chortled Stafford. A few minutes later, at 11:25 p.m. EDT, back in the command module, Young received a couple of hugs, too.

Perhaps Stafford might not have been quite so welcoming had he realised that Young had used some of his relatively private time, alone in Charlie Brown, performing his very first "bowel movement" in almost five days aboard Apollo 10. Consequently, when Snoopy's ascent stage was jettisoned a few hours later, into permanent solar orbit, it carried with it a UN flag, a small flag from each state of the Union, the command module's now-unneeded docking probe, a pile of empty food packets … and Young's bag of faecal goodies. "We joked that Snoopy would have food, water, oxygen, organic material, all the ingredients for the creation of life," Stafford later wrote with glee. "Maybe a few billion years from now, some kind of Snoopy monster, distantly related to John Young, will emerge from somewhere in the Solar System … "

At 6:25 a.m. EDT on 24 May, a perfect engine burn sent Charlie Brown hurtling home. Two days later, they hit Earth's atmosphere at a lunar-return velocity of close to 25,000 mph (40,000 km/h). Cernan remembered an enormous white and violet "ball" of flame, literally sweeping up the command module like a glove. "It grew in intensity," he wrote, "and flew out behind us like the train of a bride's gown, stretching a hundred yards, then a thousand, then for miles … and the whole time we were being savagely slammed around inside the cabin."

Charlie Brown descends toward splashdown on 26 May 1969. Photo Credit: NASA

To some people, the fire and brimstone nature of re-entry illustrated God's wrath with this foul-mouthed team of space fliers. One man who was not happy, was an over-zealous Christian minister named Larry Poland. He was vocal in complaining that Stafford's crew had taken "the language of the street" with them to the Moon, and urged them to apologize for their "profanity, vulgarity and blasphemy." However, recognizing the reality that its men were in a life-or-death situation, NASA managers stood by the crew, saying they had "acted like human beings." After splashdown, they were greeted with tongue-in-cheek notices, one of which read: The Flight of Apollo 10: For Adult Audiences Only. Bob Gilruth, the head of the Manned Spacecraft Center in Houston, had burst out laughing when he heard the swearing, and veteran flight director Chris Kraft was philosophical in his autobiography, Flight. "They were out there doing man's work at the Moon," Kraft wrote. "If a cuss word or three slipped out, well, who the hell cared anyway?"

Larry Poland cared greatly and laughing it off was not good enough. In the days and weeks after the mission, hundreds of letters and telegrams flooded into NASA's Washington headquarters, some tolerating the language, others condemning it. John Young was not involved and Tom Stafford (famously nicknamed "Mumbles") had uttered his profanities under his breath. Gene Cernan, though, was well and truly in Reverend Poland's firing line. His words could neither be misconstrued nor explained away. At a news conference, Cernan apologized to the people he had offended and thanked those who understood how he came to say what he did. Privately, though, he was furious. It made no difference, he wrote, that Poland accepted his apology and forgave him, for Cernan "never got around to forgiving that self-righteous prig!"

It was the only unfortunate incident to blight a mission which had otherwise proved enormously successful; by verifying the performance of the entire Apollo spacecraft in orbit around the Moon, Apollo 10 had cleared virtually every remaining hurdle in the path to the first lunar landing. By the end of May 1969, humanity's date with destiny was less than seven weeks away.

 

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