The ASC-15 (Advance System Controller Model 15) was a digital computer developed by International Business Machines (IBM) for use on the Titan II intercontinental ballistic missile (ICBM). [1] [2] It was subsequently modified and used on the Titan III and Saturn I Block II launch vehicles.
Its principal function on these rockets was to make navigation calculations using data from inertial sensor systems. It also performed readiness checks before launch. [3] It was a digital serial processor using fixed-point data with 27-bit words. The storage was a drum memory. Electronic circuits were soldered encapsulated modules, consisting of discrete resistors, transistors, capacitors, and other components soldered together and encapsulated in a foam material. It was manufactured in the IBM plant at Owego, NY. [4]
The first inertial guidance system for the Titan II was built by AC Spark Plug, and included an inertial measurement unit based on designs from Draper Labs at MIT, and the ASC-15 computer designed and built by IBM in Owego, NY. The first Titan II missile carrying this system was launched 16 March 1962. Acquiring spares for this system became difficult, and the Air Force decided to replace it with a new system. The AC Spark Plug system, including the ASC-15, was replaced by the Delco Electronics Universal Space Guidance System (USGS) on operational Titan II missiles starting in January 1978. [5] The guidance computer in the USGS was the Magic 352, made by Delco. [6]
The ASC-15 was built on an aluminum frame about 1.5 ft × 1.5 ft × 1 ft (46 cm × 46 cm × 30 cm). [7] The sides, top and bottom were covered by pieces of laminated plastic, covered with gold-plated aluminum foil. These covers were slightly convex and ribbed for stiffness. Inside the covers were fifty-two logic sticks, each containing four welded encapsulated modules. These surrounded a bell frame housing a drum memory. [8] See Figure 2.
The drum was a thin-walled stainless steel cylinder 3 in (76 mm) long and 4.5 in (110 mm) in diameter covered with a magnetic nickel-cobalt alloy. It was driven by a synchronous motor at 6,000 rpm. The drum had 70 tracks, of which 58 were used and 12 were spare. These tracks were used as follows:
NO. TRACKS | USE OF TRACKS |
---|---|
34 | Instruction tracks |
7 | Constants |
8 | Target data |
2 | Data for temporary storage |
5 | Revolvers for extra fast access storage |
2 | Timing tracks |
The capacity of a track was 1,728 bits. Instruction words were 9-bits long, and data was stored in 27-bit words. [9]
Coincident with 58 tracks were 67 read heads and 13 write heads. While the drum was spinning at 6,000 rpm, the heads floated above the surface of the drum on a thin layer of air. When the drum was spinning up or slowing down, the heads were raised off the drum by camshafts rotated by a chain that was driven by a motor on top of the drum housing, to avoid scoring the magnetic surface. See Figure 3.
The Titan III was a space launch vehicle based on the Titan II ICBM. The ASC-15 was kept as the vehicle guidance computer, but the drum was lengthened slightly to provide 78 usable tracks, an increase of 20 over the drum used in the Titan II. The memory held 9,792 instructions (51 tracks) and 1,152 constants (18 tracks). The speed was the same as for the Titan II: 100 revolutions/second × 64 words/revolution × 27 bits/word = 172.8 kilobits/second. The time for an addition operation was 156 μs; for a multiplication, 1,875 μs; and for a division, 7,968 μs. [10]
No guidance computer was used for Saturn I Block I (missions SA-1, 2, 3 and 4). The guidance system for SA-2 is shown in Figure 4. [11] The pitch program was provided by a cam device located in the Servo Loop Amplifier Box. The sequence of events was controlled by a program device that was also used on Jupiter missiles. This was a 6-track tape recorder that sent pulses to a set of relays (the flight sequencer) to activate and deactivate various circuits in a precisely timed sequence.
The ASC-15 was first flown on SA-5, the first Saturn I Block II vehicle and the first to achieve orbit. [12] It was a passenger on this mission, not guiding the vehicle but generating test data for later evaluation. The active guidance system on SA-5 was similar to that of earlier flights. The passenger system was the ASC-15 and the ST-124 inertial platform. Guidance was open loop; that is guidance commands were functions only of time. SA-5 also saw the introduction of the Instrument Unit.
On SA-6, while open loop ST-90S guidance was used for the first stage (S-I), after separation the ST-124 and ASC-15 used path adaptive guidance (closed loop) to control the second stage (S-IV). The SA-6 guidance system is shown in Figure 5. [13] The effectiveness of the path adaptive guidance was demonstrated inadvertently when premature shutdown of S-I engine number eight had virtually no effect on the vehicle trajectory.
The arrangement of the ST-90S and ST-124 systems (including the ASC-15 guidance computer) on SA-6 is shown in Figure 6. [14] This is version 1 of the Instrument Unit, which flew on SA-5, 6, and 7.
On SA-7 the ST-124 system guided the firing of both stages. The guidance and control system for SA-7 is shown in Figure 7. [15] The digital computer is the ASC-15. It replaced both the cam device that contained the S-I tilt program for earlier missions [16] and the program device that controlled the sequence of events on those missions.
The next mission flown after SA-7 was SA-9. It carried a new version of the Instrument Unit, one that was unpressurized and 2 feet (0.61 m) shorter than version 1. Version 2 flew on the remaining Saturn I missions (SA-8, 9, and 10).[ citation needed ]
Titan was a family of United States expendable rockets used between 1959 and 2005. The Titan I and Titan II were part of the US Air Force's intercontinental ballistic missile (ICBM) fleet until 1987. The space launch vehicle versions contributed the majority of the 368 Titan launches, including all the Project Gemini crewed flights of the mid-1960s. Titan vehicles were also used to lift US military payloads as well as civilian agency reconnaissance satellites and to send interplanetary scientific probes throughout the Solar System.
MISTRAM was a high-resolution tracking system used by the United States Air Force to provide highly detailed trajectory analysis of rocket launches.
Marshall Space Flight Center, located in Redstone Arsenal, Alabama, is the U.S. government's civilian rocketry and spacecraft propulsion research center. As the largest NASA center, MSFC's first mission was developing the Saturn launch vehicles for the Apollo program. Marshall has been the lead center for the Space Shuttle main propulsion and external tank; payloads and related crew training; International Space Station (ISS) design and assembly; computers, networks, and information management; and the Space Launch System. Located on the Redstone Arsenal near Huntsville, MSFC is named in honor of General of the Army George C. Marshall.
The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage intercontinental ballistic missile (ICBM), in use from 1959 until 1962. Though the SM-68A was operational for only three years, it spawned numerous follow-on models that were a part of the U.S. arsenal and space launch capability. The Titan I was unique among the Titan models in that it used liquid oxygen and RP-1 as propellants; all subsequent versions used storable propellants instead.
A guidance system is a virtual or physical device, or a group of devices implementing a controlling the movement of a ship, aircraft, missile, rocket, satellite, or any other moving object. Guidance is the process of calculating the changes in position, velocity, altitude, and/or rotation rates of a moving object required to follow a certain trajectory and/or altitude profile based on information about the object's state of motion.
Saturn-Apollo 3 (SA-3) was the third flight of the Saturn I launch vehicle, the second flight of Project Highwater, and part of the American Apollo program. The rocket was launched on November 16, 1962, from Cape Canaveral, Florida.
The Saturn IB(also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage, with the S-IVB. The S-IB first stage also increased the S-I baseline's thrust from 1,500,000 pounds-force (6,700,000 N) to 1,600,000 pounds-force (7,100,000 N) and propellant load by 3.1%. This increased the Saturn I's low Earth orbit payload capability from 20,000 pounds (9,100 kg) to 46,000 pounds (21,000 kg), enough for early flight tests of a half-fueled Apollo command and service module (CSM) or a fully fueled Apollo Lunar Module (LM), before the larger Saturn V needed for lunar flight was ready.
The Saturn I was a rocket designed as the United States' first medium lift launch vehicle for up to 20,000-pound (9,100 kg) low Earth orbit payloads. Its development was taken over from the Advanced Research Projects Agency (ARPA) in 1958 by the newly formed civilian NASA. Its design proved sound and flexible. It was successful in initiating the development of liquid hydrogen-fueled rocket propulsion, launching the Pegasus satellites, and flight verification of the Apollo command and service module launch phase aerodynamics. Ten Saturn I rockets were flown before it was replaced by the heavy lift derivative Saturn IB, which used a larger, higher total impulse second stage and an improved guidance and control system. It also led the way to development of the super-heavy lift Saturn V which carried the first men to landings on the Moon in the Apollo program.
The Saturn V instrument unit is a ring-shaped structure fitted to the top of the Saturn V rocket's third stage (S-IVB) and the Saturn IB's second stage. It was immediately below the SLA (Spacecraft/Lunar Module Adapter) panels that contained the Apollo Lunar Module. The instrument unit contains the guidance system for the Saturn V rocket. Some of the electronics contained within the instrument unit are a digital computer, analog flight control computer, emergency detection system, inertial guidance platform, control accelerometers, and control rate gyros. The instrument unit (IU) for Saturn V was designed by NASA at Marshall Space Flight Center (MSFC) and was developed from the Saturn I IU. NASA's contractor to manufacture the Saturn V Instrument Unit was International Business Machines (IBM).
The Titan II was an intercontinental ballistic missile (ICBM) developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally designed and used as an ICBM, but was later adapted as a medium-lift space launch vehicle to carry payloads to Earth orbit for the United States Air Force (USAF), National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA). Those payloads included the USAF Defense Meteorological Satellite Program (DMSP), NOAA weather satellites, and NASA's Gemini crewed space capsules. The modified Titan II SLVs were launched from Vandenberg Air Force Base, California, up until 2003.
Titan IV was a family of heavy-lift space launch vehicles developed by Martin Marietta and operated by the United States Air Force from 1989 to 2005. Launches were conducted from Cape Canaveral Air Force Station, Florida and Vandenberg Air Force Base, California.
The Launch Vehicle Digital Computer (LVDC) was a computer that provided the autopilot for the Saturn V rocket from launch, through Earth orbit insertion, and the trans-lunar injection burn that would send the Apollo spacecraft to the Moon. Designed and manufactured by IBM's Electronics Systems Center in Owego, New York, it was one of the major components of the Instrument Unit, fitted to the S-IVB stage of the Saturn V and Saturn IB rockets. The LVDC also supported pre- and post-launch checkout of the Saturn hardware. It was used in conjunction with the Launch Vehicle Data Adaptor (LVDA) which performed signal conditioning from the sensor inputs to the computer from the launch vehicle.
The ST-124-M3 inertial platform was a device for measuring acceleration and attitude of the Saturn V launch vehicle. It was carried by the Saturn V Instrument Unit, a 3-foot-high (0.91 m), 22-foot-diameter (6.7 m) section of the Saturn V that fit between the third stage (S-IVB) and the Apollo spacecraft. Its nomenclature means "stable table" (ST) for use in the Moon mission (M), and it has 3 gimbals.
The Redstone Test Stand or Interim Test Stand was used to develop and test fire the Redstone missile, Jupiter-C sounding rocket, Juno I launch vehicle and Mercury-Redstone launch vehicle. It was declared an Alabama Historic Civil Engineering Landmark in 1979 and a National Historic Landmark in 1985. It is located at NASA's George C. Marshall Space Flight Center (MSFC) in Huntsville, Alabama on the Redstone Arsenal, designated Building 4665. The Redstone missile was the first missile to detonate a nuclear weapon. Jupiter-C launched to test components for the Jupiter missile. Juno I put the first American satellite Explorer 1 into orbit. Mercury Redstone carried the first American astronaut Alan Shepard into space. The Redstone earned the name "Old Reliable" because of this facility and the improvements it made possible.
The Saturn V dynamic test vehicle, designated SA-500D, is a prototype Saturn V rocket used by NASA to test the performance of the rocket when vibrated to simulate the shaking which subsequent rockets would experience during launch. It was the first full-scale Saturn V completed by the Marshall Space Flight Center (MSFC). Though SA-500D never flew, it was instrumental in the development of the Saturn V rocket which propelled the first men to the Moon as part of the Apollo program. Built under the direction of Dr. Wernher von Braun, it served as the test vehicle for all of the Saturn support facilities at MSFC.
The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had three stages, and was powered by liquid fuel. Flown from 1967 to 1973, it was used for nine crewed flights to the Moon, and to launch Skylab, the first American space station.
Autonetics was a division of North American Aviation that produced various avionics but is best known for their inertial navigation systems used in submarines and intercontinental ballistic missiles. Its 188-acre facility in Anaheim, California, with 36,000 employees, was the city's largest employer. Through a series of mergers, Autonetics is now part of Boeing.
The Titan II GLV or Gemini-Titan II was an American expendable launch system derived from the Titan II missile, which was used to launch twelve Gemini missions for NASA between 1964 and 1966. Two uncrewed launches followed by ten crewed ones were conducted from Launch Complex 19 at the Cape Canaveral Air Force Station, starting with Gemini 1 on April 8, 1964.
Walter Haeussermann was a German-American aerospace engineer and member of the "von Braun rocket group", both at Peenemünde and later at Marshall Space Flight Center, where he was the director of the guidance and control laboratory. He was awarded the Department of the Army Decoration for Exceptional Civilian Service in 1959 for his contributions to the US rocket program.
The 6555th Aerospace Test Group is an inactive United States Air Force unit. It was last assigned to the Eastern Space and Missile Center and stationed at Patrick Air Force Base, Florida. It was inactivated on 1 October 1990.