Mercury and Gemini
The ladder NASA climbed to reach the Moon had three rungs of achievement -- the Mercury, Gemini and Apollo programs. The first program, Project Mercury, was initiated on Oct. 7, 1958, just six days after the founding of NASA. Its objective was to orbit and retrieve a manned Earth satellite.
In mid-September of 1958 the National Advisory Committee for Aeronautics (NACA), NASA's predecessor agency, and the Advanced Research Projects Agency had established a Joint Manned Satellite Panel. After NASA took the place of NACA, it organized a Space Task Group at its Langley Research Center to direct the program. The group was responsible directly to NASA Headquarters.
Although the X-1 and other research rocket-planes had taken American pilots to the fringes of space and although the principal problems posed by living in weightlessness (eating, drinking, and elimination) were easily solved, there remained physiological and psychological unknowns. Radiation, isolation, and re-entry stresses had to be overcome before people could venture into orbit. Moreover, rockets had to be made more reliable, or "man-rated."
The rocket chosen to carry the Mercury payload into orbit was an Atlas IntercontinentaI Ballistic Missile (ICBM). "Big Joe" was one such missile, capped with a full-scale Mercury spacecraft. Launched on Sept. 9, 1959, it tested the heat shield which protected the capsule from the searing temperatures endured during re-entry. The capsule survived, and an autopsy on the heat shield proved its structural integrity.
"Little Joe" was a special booster, simple and relatively inexpensive, which carried a primate passenger named Sam through 3 minutes of weightlessness back to safety on Earth. The rocketing rhesus monkey's flight also tested the worldwide tracking network for Mercury.
Other early developmental flights in the Mercury program were not so successful. Mercury-Atlas 1 exploded one minute into its flight-causing the program a six-month delay. Mercury-Redstone 1 had a very short liftoff. It rose 4 or 5 inches (10 to 13 centimeters) before settling back on its fins, while the escape tower launched-without its attached capsule. On a manned mission, the tower was supposed to carry an astronaut to safety if the flight were aborted.
The repeat flight of the Redstone (1A), 28 days later, was a success, as was the Mercury-Redstone 2 flight of the astrochimp Ham, launched in January 1961. On his 16-minute suborbital flight, Ham performed a series of tasks for which he had been trained, functioning in space like a normal chimpanzee.
The Redstone rocket, though not powerful enough to place the Mercury capsule in orbit, was selected for two suborbital manned flights. On May 5, 1961, astronaut Alan B. Shepard Jr. became America's first man in space. Inclement weather, a faulty inverter in the electrical system and a computer problem caused slight delays in the launch. But the mission of Mercury-Redstone 3 went smoothly after it finally left the pad, with Shepard demonstrating no ill effects from either weightlessness or gravitational stresses.
Shepard's 15-minute suborbital flight in Freedom 7 took him 302 miles (486 kilometers) from Cape Canaveral. He was weightless for 5 minutes, cramped with equipment in a space capsule 9.5 feet (2.9 meters) high and 6 feet (1.8 meters) in diameter at its base.
The next suborbital flight, flown by Virgil I. Grissom, also lasted 15 minutes. The launch on July 21 had one major hold when a gantry technician discovered that one of the 70 bolts of the space capsule escape latch was improperly aligned. The problem was corrected and the countdown continued.
A serious emergency occurred during splashdown, when the capsule hatch opened and seawater flooded in. Grissom was forced to abandon ship. His Liberty Bell 7 sank to the bottom of the ocean.
Mercury-Atlas 3 was supposed to carry a "mechanical astronaut" into orbit, but its booster failed. In September, Mercury-Atlas 4 was launched on a successful one-orbit mission. Its instruments monitored levels of noise, vibration and radiation. Mercury-Atlas 5 was a two-orbit chimpanzee flight. The chimp Enos, Hebrew or Greek for "man," overheated but was recovered unharmed.
John H. Glenn Jr. was selected as the first U.S. astronaut who would attempt to enter orbit, propelled by an Atlas vehicle. The launching was postponed repeatedly because of technical problems in the fuel tanks, bad weather, a slipped thermistor on Glenn's suit, a broken hatch bolt, a stuck valve, too little propellant in the booster's tank, and a power failure at the Bermuda tracking station.
These problems were all solved and on Feb. 20, 1962, almost a month past the initial launch date, Friendship 7, with Glenn aboard, blasted into orbit. On the second and third orbits, because of difficulty with the automatic stabilization and control system, Glenn had to take manual control -- to fly-by-wire in space jargon -- and so had to omit many of the assigned observations.
A serious problem occurred during re-entry. Data telemetered to Earth indicated that the heat shield was no longer locked in place. A spent retropackage was left underneath the shield in hope that it would keep it in place during the blazing re-entry from orbit. Glenn survived, and the heat shield was found intact; it was the telemetered data that had been wrong.
M. Scott Carpenter flew three orbits in Aurora 7 in May 1962, with more pilot control of the mission, including inverted flight (pilot's head oriented toward Earth). Walter M. Schirra Jr. completed six orbits in Sigma 7 in October 1962. And in May 1963, L. Gordon Cooper made the last flight of the Mercury program, called the "daylong" mission, in Faith 7. He orbited 22 times and splashed down 34 hours and 20 minutes after liftoff.
One of the lessons learned in Mercury was how much time final launch preparations took at the spaceport. NASA decided to build an automated digital system to reduce the spacecraft's time on the flightline in the future. This was called the Acceptance Checkout Equipment (ACE).
Built on the foundations Mercury had already established, the Gemini program was the next major step to the Moon. Gemini, as the name reflects, was a two-man spacecraft, far more sophisticated than the Mercury capsule, although they looked much alike. For a while it was known as the Mercury Mark II. Gemini was launched by a Titan II missile, developed by the Air Force.
Gemini's accomplishments included the first rendezvous of one spacecraft with another -- an extremely difficult maneuver because of the astronavigation involved; the first docking of a spacecraft to another propulsive stage, and use of that stage to propel the spacecraft into a higher orbit; and the first human travel into the Earth's radiation belts. With this program, the United States surpassed the Soviet Union in manned space flight.
In 1961, President Kennedy had committed the nation to putting an astronaut on the Moon before the end of the decade. Gemini would demonstrate capabilities needed for lunar flight: rendezvous and docking, duration of mission for up to two weeks, and controlled landing.
Gemini-Titan 1, an unmanned launch vehicle, gave an almost flawless performance in March 1964. So did the second unmanned Gemini-Titan in January of the next year, after a myriad of problems prior to launch. In August 1964, lightning struck Complex 19 at the Cape. Then Hurricane Cleo brushed the coast, followed by scares from her sisters Dora and Ethel. The countdown finally started on Dec. 8. The first-stage engines ignited and sprang into life, only to be shut down one second later because the vehicle lost hydraulic power in its primary control unit. For the first time, launch crews had to drain hypergolics--propellants that ignite upon contact with each other--from a vehicle at the pad. Launch on Jan. 19, 1965, was successful.
On March 23, after a 22-month gap in U.S. manned missions, Grissom and John Young were launched on a three-orbit flight on Gemini-Titan 3. Grissom, whose first spacecraft had sunk to the ocean bottom, nicknamed this one "Molly Brown" after the "unsinkable" heroine of a Broadway musical. The astronauts did the first maneuvering in orbit with Molly Brown.
On the Gemini 4 mission flown by James A. McDivitt and Edward H. White 11, White became the first American to "walk" in space when he performed a 20-minute extravehicular activity. White wore a space suit which weighed 31 pounds (14 kilograms) and contained 18 layers of material to protect him from heat, cold, and meteoroids, and to maintain internal space suit pressure.
The Gemini 5 mission in August 1965, with Cooper and Charles Conrad Jr. at the controls, was an eight-day voyage. It was the first flight to use fuel cells instead of storage batteries to produce electricity. The cells provided electrical power through the reaction of liquid hydrogen and liquid oxygen, a method which allowed manned flights to continue longer.
Gemini 6 was to be a rendezvous mission, incorporating an Atlas-Agena as a target vehicle. But the Agena exploded soon after launch in October 1965.
Two McDonnell officials, Walter Burke, the spacecraft chief, and John Yardley, his deputy, suggested performing a rendezvous mission by flying Gemini 6 and 7, two manned vehicles, at the same time. On Dec. 4, 1965, Gemini 7 was launched, carrying astronauts Frank Borman and James A. Lovell Jr. on their 14-day mission. On Dec. 15, Gemini 6-A, with Schirra and Thomas P. Stafford, followed the path to orbit. That same day it rendezvoused with Gemini 7. This was the first time the tracking network had simultaneously tracked and acquired information from two orbiting manned spacecraft.
The Atlas-Agena for Gemini 8 was launched into a circular orbit on March 16, 1966. The Gemini, with astronauts Neil A. Armstrong and David R. Scott, followed, and rendezvoused and docked with the Agena. Soon afterward, the docked vehicles began rolling in a mad whirl, forcing Armstrong to undock. The Gemini continued revolving; one of the maneuver thrusters had stuck open. Armstrong turned off the maneuvering system and turned on the re-entry control system, which restored pilot control. Cutting the mission short, they landed the same day.
Tragedy struck the space program when astronauts Elliot M. See and Charles A. Bassett II, scheduled to fly Gemini 9, died in a crash of a T-38 jet aircraft. Flying into St. Louis in poor weather conditions, they crashed into the roof of a building near the airfield. Ironically, this facility, McDonnell Building 101, housed the spacecraft they were to ride into orbit. Gemini 9 backups Stafford and Eugene A. Cernan replaced See and Bassett on Gemini 9. Their target vehicle, an Atlas-Agena, lifted off on May 17, 1966 -- and immediately flipped over into a nose dive.
An alternate target was available. After the Agena explosion of October 1965, NASA had ordered a backup Atlas called the Augmented Target Docking Adapter (ATDA). It consisted of a target docking adapter bolted to the rendezvous and recovery section of a Gemini and fitted to the Atlas. On June 1, 1966, the ATDA reached orbit, but a launch shroud protecting the docking port had failed to jettison. Gemini 9-A lifted off on June 3, and rendezvoused with the ATDA. With the shroud half-opened, it looked to Stafford like an "angry alligator." Docking was impossible. Cernan had an extravehicular activity scheduled and could have tried to remove the shroud, but the possibility of tearing his space suit on the jagged edges made the endeavor too risky.
Young and Michael Collins had better luck with their mission. Gemini 10 and its corresponding Atlas-Agena rose into orbit on July 18, 1966. Young docked with the Agena and fired its main engine to propel both vehicles into a higher orbit. Then the Agena propelled the spacecraft to rendezvous with Gemini 8's Agena. After releasing their own Agena from bondage, they approached the other within 6.5 feet (two meters). Collins left the spacecraft, drifted over to the Agena and removed one of its experiments.
A mere two seconds was the length of the launch window for Gemini 11 -- the shortest in the Gemini program. On Sept. 12, Conrad and Richard F. Gordon Jr., in their Gemini spacecraft, were launched for a first-orbit rendezvous with an Agena stage, launched the same day as the usual Atlas booster. After rendezvous, they engaged in docking and undocking practice. Astronaut Gordon took a "space walk" with a tether attachment between the undocked Gemini and Agena. Leaving space, their automatic re-entry gave them a very accurate landing.
Nov. 12, 1966, saw the beginning of the end of the Gemini program. As Lovell and Edwin E. Aldrin Jr. took the pad elevator up to Gemini 12, they carried signs on their backs, "The" and "End." After launch of the manned spacecraft and its Agena target, the Gemini's radar failed. They were able to rendezvous anyway, using sextant measurements, thanks to the expertise of Aldrin, whose nickname was "Dr. Rendezvous."
Project Gemini closed with the splashdown of Gemini 12. The experience gained from the intermediate manned space flight program was applied to Apollo technology even before the Gemini program ended. As modifications were made to upcoming Gemini hardware, those same innovations were incorporated into the design of Apollo. Apollo engineers and managers welcomed the baton they were handed and began the final stretch to the Moon.