Thor-Able 127 being prepared for launch at the Cape Canaveral Air Force Station. (U.S. Air Force)
17 August 1958: In what was the first attempt to launch a spacecraft beyond Earth orbit, Thor-Able 1 (Missile Number 127) was to place a small instrumented satellite in orbit around the Moon. Called Pioneer,¹ the satellite carried a television camera, a micrometeorite detector and a magnetometer.
The mission was carried out by the U.S. Air Force Ballistic Missile Division and the Advanced Research Projects Agency (ARPA).
The Thor-Able lifted off from Launch Complex 17A at the Cape Canaveral Air Force Station, Florida, at 12:28:00 UTC, 4 minutes behind schedule.
73.6 seconds into the flight, at an altitude of 9.9 miles (16 kilometers), the first stage of the rocket exploded. Telemetry from the upper stages continued and was tracked until impact in the Atlantic Ocean.
An investigation found the cause of the explosion to be a turbopump failure. It was determined that a bearing in the pump’s gearbox seized, halting the flow of liquid oxygen.
The Thor Able was a two-stage orbital launch vehicle which was developed from the Douglas Aircraft Company’s SM-75 Thor intermediate-range ballistic missile.
Designated Thor DM-19, the first stage was 60.43 feet (18.42 meters) long and 8 feet (2.44 meters) in diameter. Fully fueled, the first stage had a gross weight of 108,770 pounds (49,337 kilograms). It was powered by a Rocketdyne LR-79-7 engine which burned liquid oxygen and RP-1 (a highly-refined kerosene rocket fuel) and produced 170,565 pounds of thrust (758.711 kilonewtons). This stage had a burn time of 2 minutes, 45 seconds.
The second stage was an Aerojet General Corporation-built Able, a second stage for the U.S. Navy’s Vanguard rocket. It was 21 feet, 6.6 inches (6.57 meters) long with a maximum diameter of 2 feet, 9 inches (0.84 meters), and had a gross weight of 5,000 pounds (2,268 kilograms). It used an Aerojet AJ10-101 rocket engine which burned a hypergolic mixture of nitric acid and UDMH. The second stage produced 7,711 pounds of thrust (34.300 kilonewtons) and burned for 1 minutes, 55 seconds.
Thor-Able second stage being prepared to mount to the Thor 127 first stage. (Drew ex Machina)
The Altair X248 third stage was developed by the Alleghany Ballistics Laboratory for the U.S. Navy’s Vanguard rocket. It was 4 feet, 11 inches (1.499 meters) long, 2 feet, 7 inches (0.787 meters) in diameter, and weighed 505 pounds (229 kilograms). It was powered by a solid fuel rocket engine producing 2,300 pounds (10.231 kilonewtons) of thrust. Its burn time was 38 seconds.
Thor-Able 127 lifts off from Launch Complex 17A, 17 August 1958. (NASA)
The first Pioneer space probe is today designated Pioneer 0. It was built by the Ramo-Wooldridge Corporation’s Space Technologies Laboratory (STL) in Redondo Beach, California.
The lunar probe was the fourth stage of the Thor-Able launch vehicle. It was 74 centimeters (2 feet, 5.13 inches) in diameter, 76 centimeters (2 feet, 5.9 inches) long, and weighed 38.1 kilograms (83.996 pounds). The probe’s external shell was constructed of metal and fiberglass. It carried 11.3 kilograms (24.9 pounds) of instruments designed to measure magnetic fields, radiation and micrometeorites. It also carried an infrared camera system intended to obtain close-up images of The Moon’s surface. Pioneer 0 was spin-stabilized, turning 108 r.p.m.
The probe was equipped with a Thiokol TX-8-6 solid rocket engine to decelerate it for entry into lunar orbit. The rocket engine was the main structural component of the probe. There were 8 vernier rockets to correct its trajectory.
Space Technologies Laboratory Pioneer lunar orbiter. (STL/Drew ex Machina)
The Thiokol TX-8 was produced at the U.S. Army’s Longhorn Army Ammunition Plant near Karnack, Texas. It was designed to power the GAR-1 Falcon radar-homing air-to-air guided missile (later designated AIM-4 Falcon). The rocket motor weighed 11 kilograms (24.3 pounds).
Arrangement of equipment within the Pioneer lunar orbiter. (Drew ex Machina)
The Thor Delta launch vehicle at Launch Complex 17A, Cape Canaveral Air Force Station. The spherical capsule containing the Echo 1A is visible at the top of the Altair solid fuel third stage. (NASA)
12 August 1960: At 5:39:43 a.m., Eastern Daylight Savings Time, the Echo 1A experimental passive communications satellite was launched from LC-17A at Cape Canaveral Air Force Station, Florida. The launch vehicle was a Thor-Delta three stage rocket. It entered a nearly circular 944 mile × 1,048 mile orbit (1,519 × 1,687 kilometers). The orbital period was 118.3 minutes.
The satellite was a 100 foot diameter (30.48 meter) Mylar polyester balloon with a reflective surface. The material was just 0.0127 millimeters thick. The mass of the satellite was 66 kilograms (145.5 pounds). In orbit, the balloon envelope was kept inflated by gas from evaporating liquid. It had been constructed by the G.T. Schjeldahl Company, Northfield, Minnesota. This was the second Echo satellite. The first had failed to reach orbit when launched 13 March 1960.
Later the same day, a microwave transmission from the Jet Propulsion Laboratory, Pasadena, California, was reflected off the Echo 1A satellite and received at the Bell Laboratories, Homdel, New York.
According to NASA, “The success of Echo 1A proved that microwave transmission to and from satellites in space was understood and demonstrated the promise of communications satellites. The vehicle also provided data for the calculation of atmospheric density and solar pressure due to its large area-to-mass ratio. Echo 1A was visible to the unaided eye over most of the Earth (brighter than most stars) and was probably seen by more people than any other man-made object in space.”
Echo 1A remained in Earth orbit until 24 May 1968.
An Echo satellite undergoing static inflation tests inside a blimp hangar at Weeksville NAS, North Carolina. The vehicle, which shows scale, is a 1959 Plymouth Suburban 4-door station wagon. (NASA)
The Delta was a three-stage expendable launch vehicle which was developed from the Douglas Aircraft Company’s SM-75 Thor intermediate-range ballistic missile.
Designated Thor DM-19, the first stage was 60.43 feet (18.42 meters) long and 8 feet (2.44 meters) in diameter. Fully fueled, the first stage had a gross weight of 108,770 pounds (49,337 kilograms). It was powered by a Rocketdyne LR-79-7 engine which burned liquid oxygen and RP-1 (a highly-refined kerosene rocket fuel) and produced 170,565 pounds of thrust (758.711 kilonewtons). This stage had a burn time of 2 minutes, 45 seconds.
The second stage was an Aerojet General Corporation-built Delta 104. It was 19 feet, 3 inches (5.88 meters) long with a maximum diameter of 4 feet, 6 inches (1.40 meters). The second stage had a gross weight of 9,859 pounds (4,472 kilograms). It used an Aerojet AJ10-104 rocket engine which burned a hypergolic mixture of nitric acid and UDMH. The second stage produced 7,890 pounds of thrust (35.096 kilonewtons) and burned for 4 minutes, 38 seconds.
The third stage was an Alleghany Ballistics Laboratory Altair 1. It was 6 feet long, 1 foot, 6 inches in diameter and had a gross weight of 524 pounds (238 kilograms). This stage used a solid-fuel Thiokol X-248 rocket engine, producing 2,799 pounds of thrust (12.451 kilonewtons). Its burn time was 4 minutes, 16 seconds.
Bumper 8 launch at Launch Complex 3, Cape Canaveral Air Force Station, Florida, 24 July 1950. The wooden structure in the foreground houses the firing crew and support personnel. (NASA)
24 July 1950: The first rocket launch at Cape Canaveral, Florida, took place. Bumper 8 was a two-stage rocket consisting of a captured German V-2 ballistic missile as the first stage and a WAC Corporal sounding rocket as the upper, second, stage. The rocket lifted off from Launch Complex 3 at the Cape Canaveral Air Force Station and followed a ballistic trajectory over the Joint Long Range Proving Ground. This was a low-angle atmospheric flight. The WAC Corporal reached an altitude of 10 miles (16.1 kilometers) and traveled 200 miles (322 kilometers) downrange.
The Bumper Project was a U.S. Army Ordnance Corps program, with overall responsibility contracted to the General Electric Corporation. The V-2s used in the Bumper Project were modified at accept the WAC Corporal second stage. Compressed air was used to separate the stages after the V-2 engine was cut off.
The V2, or Vergeltungswaffen 2 (also known as the A4, Aggregat 4) was a ballistic missile weighing 28,000 pounds (12,500 kilograms) when fully loaded. It carried a 2,200 pound (1,000 kilogram) explosive warhead of amatol, a mixture of TNT and ammonium nitrate. Propellant was a 75/25 mixture of of ethanol and water with liquid oxygen as oxidizer.
When launched, the rocket engine burned for 65 seconds, accelerating the rocket to 3,580 miles per hour (5,761 kilometers per hour) on a ballistic trajectory. The maximum range of the rocket was 200 miles (322 kilometers) with a peak altitude between 88 and 128 miles (142–206 kilometers), depending on the desired range. On impact, the rocket was falling at 1,790 miles per hour (2,881 kilometers per hour).
The V-2 could only hit a general area and was not militarily effective. Germany used it against England, France, The Netherlands and Belgium as a terror weapon. More than 3,200 V-2 rockets were launched against these countries.
At the end of World War II, many V-2 rockets and components were captured by Allied forces and were brought to the United States for research, along with many of the German engineers, scientists and technicians who had worked on the German rocket program. Others were captured by the Soviet army.
Caltech’s Jet Propulsion Laboratory Director Frank Joseph Molina with the fifth WAC Corporal sounding rocket at White Sands Missile Range. (Caltech)
The WAC Corporal was a liquid-fueled hypergolic rocket. After separation from the first stage, the WAC Corporal was capable of reaching more than 80 miles (129 kilometers). It was designed by the Jet Propulsion Laboratory in Pasadena, California, and built by Douglas Aircraft. The rocket carried small research packages into the upper atmosphere. The two-stage rocket was used to develop launch techniques and to refine the separation of upper stages at very high speed.
Now named the Kennedy Space Center, but known simply as “The Cape,” the location was selected to allow rocket testing to take place over the Atlantic Ocean, minimizing danger to persons and property. As one of the points within the United States closest to the Equator, rockets launched on an eastward trajectory receive additional velocity due to the Earth’s rotation.
Launch Complex 3 at Cape Canaveral, 28 July 1950. The Bumper 7 two-stage rocket is on the pad surrounded by a gantry structure. It was launched the day after this photograph was taken. (U.S. Air Force)
Atlantis touches down at the Shuttle Landing Facility, 0554 EDT, 21 July 2011. (NASA)
21 July 2011, 5:54:00 a.m. Eastern Daylight Time, (21:54:00 UTC) Space Shuttle Atlantis on mission STS-135, landed at Kennedy Space Center, Cape Canaveral, Florida. Wheel stop was 5:57:54 a.m., EDT.
This 13-day mission had been the thirty-third flight for Atlantis. It had spent a total of 307 days in Earth orbit.
Atlantis (STS-135) landing at he Shuttle Landing Facility. (NASA)
This brought to a close The Era of American Manned Space Flight which began 50 years, 2 months, 15 days, 20 hours, 23 minutes, 41 seconds earlier with the launch of Alan Shepard in Freedom 7, 5 May 1961, 09:34:13 EST.
The benefits of the NASA programs over these decades are immeasurable.
Mercury-Redstone 4 (Liberty Bell 7) launch at Pad 5, Cape Canaveral Air Force Station, 12 20 36 UTC, 21 July 1961. (NASA)
21 July 1961: At 7:20:36 a.m. Eastern Time (12:20:36 UTC), NASA Astronaut, Captain Virgil Ivan (“Gus”) Grissom, United States Air Force, was launched from Launch Complex 5, Cape Canaveral Air Force Station, Florida, aboard Mercury-Redstone 4.
This was the second manned flight of Project Mercury. Grissom’s Mercury space craft was named Liberty Bell 7. The Mercury space craft was a one-man capsule built by McDonnell Aircraft. The Redstone launch vehicle was a highly-modified version of a liquid-fueled U.S. Army ballistic missile.
Gus Grissom in his full-pressure suit awaits orders to man his spacecraft. After sleepin for about four hours, Grissom was awakened at 1:15 a.m. He entered the Liberty Bell 7 at 3:58 a.m., 3 hours, 22 minutes prior to launch. (NASA)
The Redstone rocket accelerated to Mach 6.97 (5,168 miles per hour, 8,317 kilometers per hour). Grissom experienced a maximum 6.3 gs of acceleration on climbout.When the booster engine shut down, the Mercury capsule was released and continued upward on a ballistic trajectory. The peak altitude reached by Liberty Bell 7 was 102.8 nautical miles (118.3 statute miles, or 190.4 kilometers). The maximum velocity, relative to Earth, was 6,618 feet per second (2,017 meters per second). Grissom was “weightless” for 5.00 minutes. The capsule traveled downrange and landed in the Atlantic Ocean 262.5 nautical (302.1 statute miles, or 486.2 kilometers) from Cape Canaveral. During the reentry phase, the maximum deceleration of Liberty Bell 7 reached 11.1 gs. Total duration of the flight was 15 minutes, 37 seconds.
Several minutes after landing in the ocean, the hatch of the spacecraft was jettisoned by explosive bolts¹ and the craft began to fill with water. Though one of the recovery helicopters, a Sikorsky HUS-1 Seahorse, Bu. No. 148755 ² (Call sign “Hunt Club 1”), piloted by Lieutenants James L. Lewis and John Reinhard, tried to recover Liberty Bell 7, it was too heavy and had to be released. The capsule sank to the ocean floor, 15,000 feet (4,572 meters) below. (The Mercury capsule was recovered from the sea 38 years later, 21 July 1999.) Grissom was picked up by the second helicopter, HUS-1 Bu. No. 148754, “Hunt Club 3.”
Hunt Club 1 attempts to lift Liberty Bell 7. The primary recovery ship, the Essex-class aircraft carrier USS Randolph (CVS-15), is on the horizon. (NASA)
Virgil Ivan Grissom was born at Mitchell, Indiana, the second of five children. Upon graduation from high school during World War II, he enlisted in the U.S. Army. After the war, he went to Purdue University and earned a Bachelor of Science Degree in engineering, then joined the U.S. Air Force and was trained as a fighter pilot. He flew 100 combat missions in the North American Aviation F-86 Sabre during the Korean War. He attended a one year program at the Air Force Institute of Technology and earned a second Bachelor’s degree in aircraft engineering. Next he went to the test pilot school at Edwards AFB. After completion, he was assigned as a fighter test pilot at Wright-Patterson AFB.
One of 508 pilots who were considered by NASA for Project Mercury, Gus Grissom was in the group of 110 that were asked to attend secret meetings for further evaluation. From that group, 32 went on with the selection process and finally 18 were recommended for the program. Grissom was one of the seven selected.
Gus Grissom in the cockpit of his 1963 Corvette Stingray.
Captain Grissom was the second American to “ride the rocket.” He named his space capsule Liberty Bell 7. Next he orbited Earth as commander of Gemini III along with fellow astronaut John Young. He was back-up commander for Gemini VI-A, then went on to the Apollo Program.
As commander of AS-204 (Apollo I), LCOL Virgil I. Grissom, USAF was killed along with Ed White and Roger Chafee in a disastrous launch pad fire, 27 January 1967.
Gus Grissom was an Air Force Command Pilot with over 4,600 hours flight time. He was the first American astronaut to fly into space twice.
Project Mercury spacecraft under construction at McDonnell Aircraft Corporation, St. Louis, Missouri. (NASA)
Liberty Bell 7 (Mercury spacecraft number 11) differed from Alan Shepard’s Mercury capsule with the addition of a large viewing window and a side hatch equipped with explosive bolts. There were also differences in the capsule’s instrument panel, as well as other improvements. The MR-4 capsule was delivered to Cape Canaveral on 7 March 1961. The space capsule was truncated cone with sides angled 20° from the longitudinal axis. It was 6 feet, 10 inches (2.083 meters) long and had a maximum diameter of 6 feet, 2.50 inches (1.892 meters). The total height of the spacecraft, from the tip of the aero spike to the booster adapter, was 26 feet, 1.26 inches (7.957 meters). At launch, Mercury 11 weighed approximately 2,835 pounds (1,286 kilograms), empty.
During flight outside the atmosphere, the Mercury spacecraft could be controlled in its pitch, roll and yaw axes by hydrogen peroxide-fueled reaction control thrusters. Both manual and automatic attitude control were available. It could not accelerate or decelerate (except for reentry) so it could not change its orbit.
The spacecraft cabin was pressurized to 5.5 psi with 100% oxygen. The pilot wore a B.F. Goodrich Mark IV Model 3 Type I full-pressure suit and flight helmet for protection in the event that cabin pressure was lost.
The Redstone MRLV rocket was a redesigned, “man rated” version of the Chrysler-built United States Army M8 medium-range nuclear-armed ballistic missile. More than 800 changes were made. It was lengthened 6 feet ( meters) to provide greater fuel capacity, which increased the rocket’s “burn time” by 20 seconds. A pressurized instrumentation section was added, the control systems were simplified for greater reliability, and an inflight abort sensing system was installed. The rocket fuel was changed from hydrazine to ethyl alcohol. The cylindrical booster was 59.00 feet (17.983 meters) long and 5 feet, 10 inches (1.778 meters) in diameter. The rocket had four guidance fins with rudders mounted at the tail section. (Interestingly, the Redstone stood freely on the launch pad. No hold-downs were used. The guidance fins supported the entire weight of the vehicle.) Six Redstone MLRBs were built for Project Mercury.
The Redstone MRLV was powered by a single NAA 75-110-A7 liquid-fueled engine built by the Rocketdyne Division of North American Aviation, Inc., at Canoga Park, California. The A7 produced 78,000 pounds of thrust (346.96 kilonewtons) at Sea Level, and 89,000 pounds (395.89 kilonewtons) in vacuum, burning ethyl alcohol with liquid oxygen.
The total vehicle height of Mercury-Redstone 4, including the booster, adapter, capsule and escape tower, was 83.38 feet (25.414 meters). The total vehicle launch weight was approximately 66,000 pounds (29,937 kilograms).
Virgil Ivan (“Gus”) Grissom, NASA Project Mercury Astronaut. (Ralph Morse/LIFE Magazine)
¹ “The mystery of Grissom’s hatch was never solved to everyone’s satisfaction. Among the favorite hypotheses were that the exterior lanyard might have become entangled with the landing bag straps; that the ring seal might have been omitted on the detonation plunger, reducing the pressure necessary to actuate it; or that static electricity generated by the helicopter had fired the hatch cover. But with the spacecraft and its onboard evidence lying 15,000 feet down on the bottom of the Atlantic Ocean, it was impossible to determine the true cause. [377] The only solution was to draft a procedure that would preclude a recurrence: henceforth the astronaut would not touch the plunger pin until the helicopter hooked on and the line was taut. As it turned out, Liberty Bell 7 was the last manned flight in Project Mercury in which helicopter retrieval of the spacecraft was planned. In addition, Grissom would be the only astronaut who used the hatch without receiving a slight hand injury. As he later reminded Glenn, Schirra, and Cooper, this helped prove he had not touched his hatch plunger.”
—This New Ocean: A History of Project Mercury, by Loyd S. Swenson, Jr., James M. Grimwood, and Charles C. Alexander. NASA Special Publication SP-4201, 1989
² After retiring from military service, Sikorsky HUS-1 Seahorse Bu. No. 147755 (redesignated UH-34D in 1962) was sold to the civil market, and was registered N4216H, 10 March 1981. It was owned by Orlando Helicopter Airways, Inc., Orlando, Florida. The FAA registration was cancelled in 2013. The status of the helicopter is not known.
