NASA - National Aeronautics and Space Administration

Steps Toward Lunar Landing

For the men and women who planned the Apollo program in 1961, and for thousands of others who designed, fabricated, and tested the Saturn V launch vehicle and Apollo spacecraft, the morning of Nov. 9, 1967, was to be the ultimate test. The years spent in planning and constructing facilities, and in organizing the largest launch team ever assembled in this country, were about to pay off.

Since the earlier Saturns had been designated the 200 series, NASA had numbered the Saturn Vs the 500 series. Consequently, the first to be launched became Apollo-Saturn 501, and since this was the fourth Apollo scheduled, the mission became Apollo 4.

The flight hardware coming off production lines and static test stands had been arriving at the Center since mid-1966. At nightfall on Aug. 25, 1967, the crawler moved into the VAB, jacked up the mobile launcher and space vehicle and prepared to transfer the 12 million-pound (5.4 million-kilogram) assembly to the launch pad. Early in the morning of Aug. 26, the towering mass of the mobile launcher carrying Apollo 4 slowly emerged from the building.

In mid-September, bad weather hampered tests of the liquid hydrogen fueling system at the pad. Gale-force winds were measured on the mobile launcher. The following week, lightning and heavy rainfall postponed the countdown demonstration test, which verifies that rocket and spacecraft systems and equipment are ready for launch.

Three times between Sept. 27 and Oct. 31, the test was temporarily halted by a succession of annoying problems. When it was finally completed, Center management felt that a major step had been accomplished -- the approximately 450-person crew in Firing Room 1 and the men on the pad had coordinated their efforts over a three-shift working day, developing confidence among the government/industry team members.

The 104-hour countdown began Oct. 30 when the spacecraft was fueled, and RP1 kerosene fuel was loaded into the first stage. On Nov, 8, wind velocities were marginal. The Apollo-Saturn V configuration could not be launched if the steady wind force was at 28 knots (52 kilometers). The weather forecaster predicted that maximum gusts would not exceed 26 knots (48 kilometers) at scheduled liftoff time on Nov. 9. It was decided to proceed with the terminal count and look at the wind situation again later.

Preplanned holds were provided in the countdown. Some of this reserve time was consumed when a scratched seal had to be replaced in the Saturn V. Another two-hour hold became necessary to check out the range safety command system.

The count proceeded until 3 a.m., Nov. 9, when the clock was stopped for 60 minutes in order to reach T minus zero at 7 a.m. Then there would be ample light for cameras to record every event on the launch pad, as well as the behavior of the launch vehicle from ignition until it disappeared out of camera view downrange.

Ignition occurred exactly on schedule, 8.9 seconds before liftoff. Six seconds later the giant engines had built up to 90 percent thrust. The hold-down arms constraining the rocket to the deck released at 7:00:01 a.m. EDT. The first Saturn V had begun its journey.

Following burnout and separation of the first and seconds stages, the third stage flamed into life to insert the spacecraft into Earth orbit. The stage was shut down, then later re-ignited to increase both the speed and altitude of the combined vehicle. When the third stage burned out, it was jettisoned. Then the Apollo spacecraft propulsion system burned for 16 seconds, raising its altitude to over 11,170 miles (18,000 kilometers). Apollo was reoriented and the engine fired once more to drive the spacecraft back into the atmosphere at 25,000 miles (40,200 kilometers) per hour, the speed Apollo would reach on its return trip from the Moon.

After spacecraft recovery, examination showed that the heat protection afforded by the blunt ablation shield on the command module had withstood the test of more than 5,000 degrees Fahrenheit (2,760 degrees Celsius). The temperature inside the Apollo spacecraft climbed only 10 degrees, and never exceeded 70 degrees. Performance of both rocket and spacecraft had been letter-perfect throughout the mission.

Following the success of Apollo 4, preparations moved ahead smoothly at Complex 37 for the first orbital test of the lunar module--the buglike spacecraft designed to land men on the Moon. The launch vehicle would be a Saturn IB, Apollo-Saturn 204.

Known as Apollo 5, the mission began the morning of Jan. 22, 1968, when the unmanned rocket rose from its launch pad carrying the lunar module. Within minutes, the spacecraft was inserted into Earth orbit as planned, then separated from its carrier rocket.

From that point on, the module responded both to programmed commands and to new instructions transmitted by radio links from the Mission Control Center in Houston. Both ascent and descent propulsion systems operated satisfactorily. The flight demonstrated that these systems could be throttled while operating, and that the engines could be started, stopped and restarted in space. No attempt was made to return the lunar module to Earth. It was not designed to withstand re-entry heating and could only function properly in space or in the one-sixth Earth gravity on the surface of the Moon.

On Feb. 6, the second Saturn V launch vehicle was carried by the crawler-transporter from the VAB to Pad A in preparation for the launch of Apollo 6. This was to be another test of the launch vehicle, and the second flight test of the command module's ability to withstand re-entry heating at lunar return velocities.

Apollo 6 was launched on schedule the morning of April 4, carrying a payload of 93,885 pounds (42,586 kilograms) into Earth orbit. The countdown went smoothly. Both vehicle and spacecraft responded to all checkout procedures and prelaunch tests. However, some problems occurred during the powered flight of the Saturn V first stage, including severe up-and-down vibrations. Then one of the five engines in the hydrogen-fueled second stage shut down prematurely, and three seconds later a second engine ceased to function. To compensate for this loss of thrust, the third stage burned 29 seconds longer than planned. This resulted in the Apollo spacecraft being inserted into orbit, and the mission continued.

Later, another problem developed. The third stage failed to re-ignite as programmed. Consequently, it did not boost the Apollo spacecraft high enough above the Earth to simulate a return from the Moon. After Apollo had been separated from the stage, it was maneuvered higher by ground control of the service module propulsion system. From this elevation Apollo was steered into re-entry almost at the original planned speed. The 10-hour flight terminated with the recovery of the spacecraft in the Pacific-Apollo had stood up well under this severe test.

As the launch vehicle designers examined the performance data accumulated during the flight of the Saturn V, they determined that the shutdown of the second stage engines had occurred because of a wiring error. They also found that spark igniters linked to the second and third stage engines failed to operate properly. That explained why the third stage failed to re-ignite in Earth orbit. They also learned that the engines of the first stage operated synchronously, causing unacceptable longitudinal oscillations. (All of this data was available because of the instrumented measurement program installed at KSC.) The government/industry team plunged into the task of finding solutions.

The causes were pinpointed quickly, and convincingly demonstrated by the ground testing of similar systems. Marshall's engineers proved that by introducing helium into the propellant lines of the first (booster) stage engines, the "pogo effect" (as the press described the longitudinal oscillations) could be suppressed. Spark igniter lines of the second and third stages were strengthened.

In late April, Lt. Gen. Samuel Phillips, the Apollo Program director, recommended that the next Saturn V mission, Apollo-Saturn 503, be manned. The second stage was demated, or removed, from the vehicle and returned to the Mississippi Test Facility for additional hot firing to "man-rate" it--clear it for launching men--for the Apollo 8 mission.

At KSC the launch team was also busily at work at Launch Complex 34, preparing another Saturn IB rocket, Apollo-Saturn 205. It was to launch the first manned Apollo spacecraft, identified as Apollo 7. In late July the prime crew -- Walter M. Schirra, Jr., Walter Cunningham, and Donn F. Eisele -- successfully completed altitude chamber tests. The backup crew of Thomas P. Stafford, John W. Young, and Eugene A. Cernan also completed these grueling tests.

The spacecraft was transferred to Complex 34 in mid-August and mounted atop the Saturn IB launch vehicle. Between Sept. 11 and 16, the launch team carried out the countdown demonstration test. This was followed by the four-day flight readiness test, in which the astronauts participated.

Representatives from NASA Headquarters and the Johnson, Marshall, and Kennedy Space Centers convened to review the status of launch preparations. On Oct. 3 they pronounced crew, rocket, and spacecraft ready to go. Apollo 7 rose from the pad at 11:02 a.m. EDT on Oct. 11.

During the orbital flight, the crew achieved every mission objective. They maneuvered Apollo to simulate docking with the slowly tumbling third stage. They tested air-to-ground communications, ignited the Apollo service module rocket engine eight times, and verified that the functional systems of both service and command modules operated perfectly.

Apollo 7, the first manned flight since Gemini's close-out in November 1966, proved that while the Apollo 1 tragedy was costly in the extreme, hard lessons had been learned, and the necessary corrections had been made. The Apollo program was back on track.

While preparations for the Apollo 7 manned launch were under way, the launch organization checked out, assembled, and tested AS-503, the third Saturn V vehicle. This mission, designated Apollo 8, was to be the first launch of a Saturn V with an Apollo crew.

The Apollo 8 mission began when the first stage arrived Dec. 27, 1967. By early February of 1968 the configuration had reached full height with the addition of a lunar module test article and a "boilerplate" command/service module. The boilerplate module would never fly, but permitted testing to proceed while awaiting the flight module.

Originally, astronauts James A. McDivitt, David R. Scott and Russell L. Schweikart were scheduled to fly the mission. They would rendezvous and dock the modules. Then two members of the crew would transfer into the lunar ship, separate it from the command/ service module, and operate it independently in the weightless environment of space for the first time.

However, as KSC engineers subjected the flight lunar module to rigorous testing and inspection, it became increasingly evident that this module needed extensive rework modification. in fact, there was no chance of meeting the anticipated 1968 launch date. Confronted with this problem, NASA examined alternate missions not involving the lunar module.

On Aug. 19, NASA announced that the mission of Apollo 8 would involve lunar orbit. The crew previously designated for Apollo 9 -- Frank Borman, James A. Lovell, Jr. and William A. Anders -- took over the mission, since they had been preparing for such a flight. Astronauts McDivitt, Scott and Schweikart continued training for the first use of the lunar module in Earth orbit.

The launch window for Saturday, Dec. 21, opened at 7:51 a.m. EST. The countdown was relatively uneventful; however, attention turned to the weather. Conditions on Dec. 20 were far from ideal site. KSC officials decided to proceed with fueling and continue the countdown to a point within minutes of ignition, then to wait. As it turned out, the decision was sound. The next morning dawned bright and clear.

Exactly on time, the five powerful engines of the first stage roared into life. Eight seconds later, the computer released the hold-down arms, and the giant rocket rose from the launcher deck.

After the flight, the Marshall Space Flight Center engineers reported that the instrument unit guided and controlled the Saturn V with extreme accuracy. It not only steered the vehicle into precise Earth orbit, but also accurately guided it on a translunar trajectory.

Initially, the spacecraft had been traveling with its nose pointing toward the Moon. Later, to position it for going into lunar orbit, Apollo's maneuvering rockets were fired to turn it around so that the main rocket at the aft end of the service module would face the Moon. When fired in this position, it would slow the spacecraft enough to allow it to enter lunar orbit.

At 5 a.m. EST, Dec. 24, Apollo 8 had reached the third and last point of commitment. Commander Borman turned on the engine of the service module, slowed Apollo and entered lunar orbit. Shortly before 10 p.m., the crew operated the television camera in a panoramic sweep of the lunar surface. This and other live telecasts from Apollo 8 were picked up by NASA's 85-foot (26-meter) diameter dish antennas at Goldstone, Calif., and Madrid, Spain, and were then relayed to stations in Europe and the Far East, as well as in the United States. People worldwide saw the full disc of Earth from a distance of 114,000 miles (183,500 kilometers) on the outward leg of flight, and later from 195,000 miles (313,800 kilometers). They saw the Moon's surface from a distance of 60 miles (96 kilometers) and an "earthrise" as the Earth appeared over the lunar horizon.

The crew made a memorable telecast from lunar orbit that Christmas Eve: "I hope all of you back on Earth can see what we mean when we say that this is a very foreboding horizon, a rather dark and unappetizing looking place. We are going over one of our future landing sites called the Sea of Tranquility. Now you can see the long shadows of the lunar sunrise. For all people on Earth, the crew of Apollo 8 has a message that we would like to send you."

Astronaut Anders then began to read from the Book of Genesis in the Bible:

"In the beginning God created the Heaven and the Earth..." Lovell and Borman also read part of the passage and Borman concluded, "And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas, and God bless all of you -- all of you on the good Earth."

Apollo circled the Moon 10 times over the 20-hour period.

Early Christmas morning, Borman once more called upon the Apollo service module engine--this time for the sharp increase in velocity essential to breaking free of lunar gravity to begin the return trip to Earth.

To anxious listeners awaiting confirmation of the critical maneuver, seconds crawled by until Mission Control announced that telemetry confirmed the burn. Then came this message from the Moon: "Please be informed, there is a Santa Claus."

Apollo 8 was on course, on time and at the correct speed.

Apollo splashed into the Pacific Ocean in darkness, at a rate of 17 miles (27.4 kilometers) per hour, 147 hours and 11 seconds after liftoff from KSC and within three miles (4.8 kilometers) of the USS Yorktown, the recovery ship.

Following the success of Apollo 8, two major tests still needed to be conducted before astronaut crews attempted the first lunar landing. The lunar module had never operated with the Apollo command and service modules on a Saturn V. Apollo 9 was planned to subject the lunar module to strenuous testing in Earth orbit, and Apollo 10 to test it in lunar orbit. Both missions were to be manned.

The Apollo 9 lunar module was delivered to KSC in June 1968, beginning the flow of equipment and preparations for launch. By Jan. 3, 1969, the assembled space vehicle was ready to be moved to Pad A in preparation for the launch scheduled on Feb. 28.

The crew named for the flight consisted of McDivitt, commander; Scott, command module pilot; and Schweikart, lunar module pilot. Both McDivitt and Scott had flown a mission in the Gemini program. Schweikart was a space "rookie."

The countdown began on time Feb. 22 and proceeded smoothly until the day before launch, when the astronauts' chief physician, Dr. Charles Berry, advised that the crew had contracted a mild virus infection and should not fly at that time. He recommended postponing the launch. As a result, the terminal countdown began at T minus 28 hours on March 1, and concluded with liftoff on time at 11 a.m. on March 3.

The crew dubbed the command ship "Gumdrop" and the lunar module "Spider." Once again, live television from Apollo highlighted the 10-day flight.

Three hours after launch, Gumdrop pulled away from the third stage, turned around and docked with Spider, which was enclosed in a protective shroud atop the stage. The combined spacecraft orbited the Earth, while Scott fired the main engine several times to test it and to observe the behavior of the joined modules while under propulsion.

Three days out, McDivitt and Schweikart crawled through the tunnel and entered Spider. They checked the lunar module electrical systems and computer, extended legs like those that would someday touch the Moon, and fired the descent engine.

During the fifth day, McDivitt and Schweikart pulled away from Gumdrop and rotated Spider so that Scott could observe it in motion. Then they fired the lunar module engine to move three miles (4.8 kilometers) away. While 155 miles (249 kilometers) above Earth and up to 128 miles (206 kilometers) from Gumdrop, McDivitt and Schweikart put Spider through its paces for nearly six hours, simulating the descent from lunar orbit to the Moon, and the launch of the ascent stage back up from the Moon. Then they flew back to dock with Scott.

The mission ended when Apollo 9 splashed down in the Atlantic Ocean off Grand Turk Island, within 3.4 miles (5.5 kilometers) of the waiting aircraft carrier.

Shortly after the Apollo 9 splashdown, the Apollo 10 space vehicle was transferred from the Vehicle Assembly Building to Pad B, marking the first use of that launch site. In this mission the astronauts would fly to the Moon, separate the lunar module, called "Snoopy," descend to within 50,000 feet (15,240 meters) of the lunar surface, then rendezvous and dock with the command ship, called "Charlie Brown," and return to Earth.

The prime crew rehearsed for months. Commander Stafford, Command Module Pilot Young, and Lunar Module Pilot Cernan were all veterans of Gemini flights.

Launch occurred exactly on schedule, at 11 minutes before 1 p.m. EDT, May 18.

This time the docking of the command ship and the lunar module was seen in color on Earth, with Cernan photographing the operation. Two hours later, he pointed the camera at Earth to show the planet from thousands of kilometers out in space.

Once in orbit around the Moon, the crew again turned on the television cameras. For the first time, Earth viewers saw the Moon's surface in color.

May 22 was an action-packed day. Stafford and Cernan separated the lunar module from the command ship while on the dark side of the Moon, emerging to inform Earth they had done so and were flying formation, or "station-keeping," 50 feet (15 meters) from Apollo. By mid-afternoon, after completing an exhaustive checklist, the astronauts fired the descent engine and the lunar module moved into an orbit that approached the Moon closer than man had even ventured before.

At the low point of their second swing around the Moon, Stafford and Cernan prepared to fire the ascent engine to propel them to rendezvous with the command ship. Just before they separated the descent stage of the lunar module, Snoopy suddenly gyrated. Stafford immediately took manual control and restored the proper orientation. He jettisoned the descent stage, and the module stabilized. Later analysis indicated the problem resulted from a malfunction in the backup guidance system.

After eight hours of separate flight, Snoopy rendezvoused and docked with Charlie Brown. When the tunnel connecting the command module with the lunar module was secured, the lunar module was cast loose and directed into solar orbit. Charlie Brown orbited the Moon for another full day.

The next morning the crew fired Apollo's engine to achieve the velocity necessary to escape lunar gravity and enter the narrow corridor along which they would return to Earth.

On May 26, eight days and three minutes after leaving Pad B, Apollo 10 splashed down in the Pacific Ocean, east of Samoa. The dress rehearsal for lunar landing had been completed.