Misplaced Pages

#726273

132-426: It successfully carried science and technology experiments for about 5.7 years that have revealed a broad and detailed collection of space environmental data. LDEF's 69 months in space provided scientific data on the long-term effects of space exposure on materials, components and systems that has benefited NASA spacecraft designers to this day. Researchers identified the potential of the planned Space Shuttle to deliver

264-414: A DNA mutation from space exposure could yield a poisonous fruit. While incorrect, the report served to raise awareness of the experiment and generate discussion. Space seeds germinated sooner and grew faster than the control seeds. Space seeds were more porous than terrestrial seeds. At LDEF's launch, retrieval was scheduled for March 19, 1985, eleven months after deployment. Schedules slipped, postponing

396-469: A character generator and the ability to load and save programs on cassette tapes . Weisbecker's daughter, Joyce Weisbecker , was immediately drawn to the system and began writing programs for it. This included several games, which were ported to later machines based on the COSMAC. When RCA entered the game console business in the later 1970s, these games were burned to ROM cartridge form, and Joyce became

528-424: A spacecraft must travel faster than a sub-orbital spaceflight along an arcing trajectory . The energy required to reach Earth orbital velocity at an altitude of 600 km (370 mi) is about 36  MJ /kg, which is six times the energy needed merely to climb to the corresponding altitude. The escape velocity required to pull free of Earth's gravitational field altogether and move into interplanetary space

660-510: A "prototype" being delivered in 1972, but this is likely referring to the original TTL implementation. It goes on to note that an effort to reduce the processor to a two-chip implementation with deliveries in COS/MOS in 1974. It is here that the processor is first referred to as COSMAC, for COmplementary-Symmetry-Monolithic-Array Computer. It goes on to state that another lab will be producing the system in an 8-chip silicon-on-sapphire format, although

792-471: A density of one proton per four cubic meters. The density of the universe is clearly not uniform; it ranges from relatively high density in galaxies—including very high density in structures within galaxies, such as planets, stars, and black holes —to conditions in vast voids that have much lower density, at least in terms of visible matter. Unlike matter and dark matter, dark energy seems not to be concentrated in galaxies: although dark energy may account for

924-568: A go-between, using multiple instructions to perform the operations. The processor has five special I/O lines. There is a single Q output that can be set with the SEQ instruction and reset with the REQ instruction. There are four external, single-bit flag inputs, EF1, EF2, EF3, and EF4, and there are eight dedicated branch instructions to conditionally branch based on the state of those input lines. There are seven Input and seven Output port instructions that utilize

1056-519: A hazard to astronauts, even in low Earth orbit. They create aurorae seen at high latitudes in an oval surrounding the geomagnetic poles . xGeo space is a concept used by the US to refer to space of high Earth orbits , ranging from beyond geosynchronous orbit (GEO) at approximately 35,786 km (22,236 mi), out to the L2 Earth-Moon Lagrange point at 448,900 km (278,934 mi). This

1188-617: A magnetic tape recorder that was powered by a lithium sulfur dioxide battery, e.g. , the Advanced Photovoltaic Experiment (S0014), which recorded data once a day, the German Solar cell study (S1002), and the Space Environment Effects on Fiber Optics Systems (M004). Six of the seven active experiments that needed to record data used one or two Experiment Power and Data System (EPDS) modules. Each EPDS contained

1320-507: A majority of the mass-energy in the universe, dark energy's influence is 5 orders of magnitude smaller than the influence of gravity from matter and dark matter within the Milky Way. Outer space is the closest known approximation to a perfect vacuum . It has effectively no friction , allowing stars, planets , and moons to move freely along their ideal orbits , following the initial formation stage. The deep vacuum of intergalactic space

1452-403: A number of industry-leading developments taking place there. Some of the skepticism displayed by management may have had to do with the company's recent sale of their mainframe computer business to Sperry Rand with a huge writedown . Eventually, the company became interested in the system and began adapting it to their newly introduced COS/MOS fabrication system. A 1973 lab report refers to

SECTION 10

#1732851064727

1584-473: A payload to space, leave it there for a long-term exposure to the harsh outer space environment, and retrieve it for analysis on a separate mission. The LDEF concept evolved from a spacecraft proposed by NASA's Langley Research Center in 1970 to study the meteoroid environment, the Meteoroid and Exposure Module (MEM). The project was approved in 1974 and LDEF was built at NASA's Langley Research Center . LDEF

1716-502: A perigee as low as 80 to 90 km (50 to 56 mi), surviving for multiple orbits. At an altitude of 120 km (75 mi), descending spacecraft such as NASA 's Space Shuttle begin atmospheric entry (termed the Entry Interface), when atmospheric drag becomes noticeable, thus beginning the process of switching from steering with thrusters to maneuvering with aerodynamic control surfaces. The Kármán line , established by

1848-636: A practical boundary have been proposed, ranging from 30 km (19 mi) out to 1,600,000 km (990,000 mi). High-altitude aircraft , such as high-altitude balloons have reached altitudes above Earth of up to 50 km. Up until 2021, the United States designated people who travel above an altitude of 50 mi (80 km) as astronauts. Astronaut wings are now only awarded to spacecraft crew members that "demonstrated activities during flight that were essential to public safety, or contributed to human space flight safety." In 2009, measurements of

1980-592: A processing and control module, a magnetic tape recorder and two LiSO 2 batteries. One experiment (S0069) used a 4-track magnetic tape module not as part of an EPDS. Fifty-seven science and technology experiments — involving government and university investigators from the United States , Canada , Denmark , France , Germany , Ireland , the Netherlands , Switzerland , and the United Kingdom  — flew on

2112-481: A simulated Martian environment. The lithopanspermia hypothesis suggests that rocks ejected into outer space from life-harboring planets may successfully transport life forms to another habitable world. A conjecture is that just such a scenario occurred early in the history of the Solar System, with potentially microorganism -bearing rocks being exchanged between Venus, Earth, and Mars. The lack of pressure in space

2244-643: A spacecraft; similarly, " space-based " means based in outer space or on a planet or moon. The size of the whole universe is unknown, and it might be infinite in extent. According to the Big Bang theory, the very early universe was an extremely hot and dense state about 13.8 billion years ago which rapidly expanded . About 380,000 years later the universe had cooled sufficiently to allow protons and electrons to combine and form hydrogen—the so-called recombination epoch . When this happened, matter and energy became decoupled, allowing photons to travel freely through

2376-587: A stack. Although any of the available registers can be used for this technique, per programmer's preference, many use the routine supplied by RCA in the CDP1802 User Manual, where the suggested register usage is R2 = Stack Pointer, R3 = General Program Counter (PC), R4 = Call, R5 = Return, R6 = Passed Arguments Pointer (non-destructive). Even though these supportive routines are small, there is an execution speed overhead using them. (as opposed to what would be incurred if actual CALL and RET instructions were part of

2508-502: A subroutine returns, it jumps to the location immediately preceding its entry point so that after the SEP "return" instruction returns control to the caller, the register will be pointing to the right value for next usage. (the processor always increments the PC after reference and usage (retrieving the next instruction to execute), so this technique works as noted) An interesting variation of this scheme

2640-605: A volume control was implemented). Traditionally, the EF4 line is attached to the INPUT momentary pushbutton on the COSMAC Elf. Other systems might use one of the other lines. There are some other special use registers and flags, some internal, and some usable programmatically: 4-bit N, P, X, and I; 8-bit T; and 1-bit IE. On the Internet, there is many versions of a Table of the 1802 Instructions, here

2772-469: Is a continuous stream of charged particles emanating from the Sun which creates a very tenuous atmosphere (the heliosphere ) for billions of kilometers into space. This wind has a particle density of 5–10 protons /cm and is moving at a velocity of 350–400 km/s (780,000–890,000 mph). Interplanetary space extends out to the heliopause where the influence of the galactic environment starts to dominate over

SECTION 20

#1732851064727

2904-492: Is about 11,200 m/s (40,300 km/h; 25,100 mph). Orbiting spacecraft with a perigee below about 2,000 km (1,200 mi) are subject to drag from the Earth's atmosphere, which decreases the orbital altitude. The rate of orbital decay depends on the satellite's cross-sectional area and mass, as well as variations in the air density of the upper atmosphere. At altitudes above 800 km (500 mi), orbital lifetime

3036-501: Is about five times the Moon's orbital distance , but which distance is also far less than the distance between Earth and any adjacent planet. Interplanetary space within the Solar System is the space between the eight planets, the space between the planets and the Sun, as well as that space beyond the orbit of the outermost planet Neptune where the solar wind remains active. The solar wind

3168-457: Is co-populated by groups of co-orbital Near-Earth Objects (NEOs), such as horseshoe librators and Earth trojans , with some NEOs at times becoming temporary satellites and quasi-moons to Earth. Deep space is defined by the United States government as all of outer space which lies further from Earth than a typical low-Earth-orbit, thus assigning the Moon to deep-space. Other definitions vary

3300-529: Is conventionally used as the start of outer space in space treaties and for aerospace records keeping. Certain portions of the upper stratosphere and the mesosphere are sometimes referred to as "near space". The framework for international space law was established by the Outer Space Treaty , which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space . Despite

3432-496: Is divided into overlapping regions of space. Near-Earth space is the region of space extending from low Earth orbits out to geostationary orbits . This region includes the major orbits for artificial satellites and is the site of most of humanity's space activity. The region has seen high levels of space debris, sometimes dubbed space pollution , threatening any space activity in this region. Some of this debris re-enters Earth's atmosphere periodically. Although it meets

3564-554: Is done on a piece of paper. Of course sometimes the Data is moved to and from the Ram Memory section, and different Branches of the Program are done, as needed, in the flow of time. There are three types of unconditional and conditional branching in the 1802, Short and Long, and Skips. Short branches are 2-byte instructions, and use 256-byte range, single byte address, page absolute addressing in

3696-438: Is free for all nation states to explore and is not subject to claims of national sovereignty, calling outer space the "province of all mankind". This status as a common heritage of mankind has been used, though not without opposition, to enforce the right to access and shared use of outer space for all nations equally, particularly non-spacefaring nations. It prohibits the deployment of nuclear weapons in outer space. The treaty

3828-464: Is historically notable as the first CMOS microprocessor. The first production model was the two-chip CDP1801R and CDP1801U , which were later combined into the single-chip CDP1802 . The 1802 represented the majority of COSMAC production, and today the entire line is known simply as the RCA 1802 . The processor design traces its history to an experimental home computer designed by Joseph Weisbecker in

3960-487: Is located beyond the orbit of the Moon and therefore includes cislunar space. Translunar space is the region of lunar transfer orbits , between the Moon and Earth. Cislunar space is a region outside of Earth that includes lunar orbits , the Moon's orbital space around Earth and the Lagrange points . The region where a body's gravitational potential remains dominant against gravitational potentials from other bodies,

4092-475: Is measured in centuries. Below about 300 km (190 mi), decay becomes more rapid with lifetimes measured in days. Once a satellite descends to 180 km (110 mi), it has only hours before it vaporizes in the atmosphere. Space in proximity to the Earth is physically similar to the remainder of interplanetary space, but is home to a multitude of Earth–orbiting satellites and has been subject to extensive studies. For identification purposes, this volume

Long Duration Exposure Facility - Misplaced Pages Continue

4224-422: Is measured in terms of the kinetic activity of the gas, as it is on Earth. The radiation of outer space has a different temperature than the kinetic temperature of the gas, meaning that the gas and radiation are not in thermodynamic equilibrium . All of the observable universe is filled with photons that were created during the Big Bang, which is known as the cosmic microwave background radiation (CMB). (There

4356-449: Is not devoid of matter , as it contains a few hydrogen atoms per cubic meter. By comparison, the air humans breathe contains about 10 molecules per cubic meter. The low density of matter in outer space means that electromagnetic radiation can travel great distances without being scattered: the mean free path of a photon in intergalactic space is about 10  km, or 10 billion light years. In spite of this, extinction , which

4488-567: Is one link : https://www.atarimagazines.com/computeii/issue3/page52.php There is a number of Tables in the File area for logged in members of the 1802 online club for forum at https://groups.io/g/cosmacelf/files . Each Instruction is a single Byte, of 8 Bits. The 4 Bits to the Left, sometimes called High Order Hex Digit, are to do with the actual nature of the Instruction, and those 4 Bits are involved with

4620-551: Is quite likely a correspondingly large number of neutrinos called the cosmic neutrino background . ) The current black body temperature of the background radiation is about 2.7 K (−455 °F). The gas temperatures in outer space can vary widely. For example, the temperature in the Boomerang Nebula is 1 K (−458 °F), while the solar corona reaches temperatures over 1,200,000–2,600,000 K (2,200,000–4,700,000 °F). Magnetic fields have been detected in

4752-631: Is slowed by the pressure containment of blood vessels, so some blood remains liquid. Swelling and ebullism can be reduced by containment in a pressure suit . The Crew Altitude Protection Suit (CAPS), a fitted elastic garment designed in the 1960s for astronauts, prevents ebullism at pressures as low as 2 kilopascals (0.3 psi). Supplemental oxygen is needed at 8 km (5 mi) to provide enough oxygen for breathing and to prevent water loss, while above 20 km (12 mi) pressure suits are essential to prevent ebullism. Most space suits use around 30–39 kilopascals (4–6 psi) of pure oxygen, about

4884-538: Is the absorption and scattering of photons by dust and gas, is an important factor in galactic and intergalactic astronomy . Stars, planets, and moons retain their atmospheres by gravitational attraction. Atmospheres have no clearly delineated upper boundary: the density of atmospheric gas gradually decreases with distance from the object until it becomes indistinguishable from outer space. The Earth's atmospheric pressure drops to about 0.032 Pa at 100 kilometres (62 miles) of altitude, compared to 100,000 Pa for

5016-511: Is the 8-bit 'D' register (Data register). The single bit carry flag is DF (Data Flag). Most operations use the D register, including arithmetic and logic functions, and memory referencing load and store instructions. Most 16-bit operations have to work on the lower byte and then the upper byte, via D, using the DF as carry and borrow as needed. An important feature of the 1802 is a set of sixteen registers of 16 bits each, used primarily for addressing. Using

5148-447: Is the body's sphere of influence or gravity well, mostly described with the Hill sphere model. In the case of Earth this includes all space from the Earth to a distance of roughly 1% of the mean distance from Earth to the Sun, or 1.5 million km (0.93 million mi). Beyond Earth's Hill sphere extends along Earth's orbital path its orbital and co-orbital space. This space

5280-504: Is the most immediate dangerous characteristic of space to humans. Pressure decreases above Earth, reaching a level at an altitude of around 19.14 km (11.89 mi) that matches the vapor pressure of water at the temperature of the human body . This pressure level is called the Armstrong line , named after American physician Harry G. Armstrong . At or above the Armstrong line, fluids in

5412-528: Is to have two or more subroutines in a ring so that they are called in round robin order. On early hobbyist computers, tricks and techniques like this were commonly used in the horizontal refresh interrupt to reprogram the scan line address to repeat each scan line four times for the video controller. One well-known and often-used routine is known as SCRT (Standard CALL and RETURN Technique), which allows general purpose subroutine Call and Return, including passing of parameters "in line", and nested subroutines using

Long Duration Exposure Facility - Misplaced Pages Continue

5544-554: The Andromeda Galaxy was first measured. Humans began the physical exploration of space later in the same century with the advent of high-altitude balloon flights . This was followed by crewed rocket flights and, then, crewed Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. The economic cost of putting objects, including humans, into space is very high, limiting human spaceflight to low Earth orbit and

5676-467: The Bogotá Declaration , they claimed control of the segment of the geosynchronous orbital path corresponding to each country. These claims are not internationally accepted. An increasing issue of international space law and regulation has been the dangers of the growing number of space debris . A spacecraft enters orbit when its centripetal acceleration due to gravity is less than or equal to

5808-549: The Fédération Aéronautique Internationale , and used internationally by the United Nations , is set at an altitude of 100 km (62 mi) as a working definition for the boundary between aeronautics and astronautics. This line is named after Theodore von Kármán , who argued for an altitude where a vehicle would have to travel faster than orbital velocity to derive sufficient aerodynamic lift from

5940-566: The Galileo probe to Jupiter in 1989, and it remains in use in similar roles to this day. A number of early microcomputers were based on the 1802, including the COSMAC ELF (1976), Netronics ELF II , Quest SuperELF , COSMAC VIP , Comx-35 , Finnish Telmac 1800 , Telmac TMC-600 and Oscom Nano , Yugoslav Pecom 32 and 64 , and the CyberVision 2001 systems sold through Montgomery Ward in

6072-551: The International Union of Pure and Applied Chemistry (IUPAC) definition of standard pressure . Above this altitude, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar wind . The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather . The temperature of outer space

6204-572: The Kennedy Space Center on January 26. Special efforts were taken to ensure protection against contamination of the payload bay during the ferry flight. Between January 30 and 31, LDEF was removed from Columbia 's payload bay in KSC's Orbiter Processing Facility , placed in a special payload canister, and transported to the Operations and Checkout Building. On February 1, 1990, LDEF was transported in

6336-541: The Membership Card microcomputer kit that fits in an Altoids tin and the Spare Time Gizmos Elf 2000 (Elf 2K), among others. See § Emulators and simulators for other systems. The 1802 was also used in scientific instruments and commercial products. Post-1980 Chrysler and associated model vehicles use the 1802 in their second-generation Electronic Lean-Burn System, with electronic spark control, one of

6468-443: The Moon . On the other hand, uncrewed spacecraft have reached all of the known planets in the Solar System . Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation . Microgravity has a negative effect on human physiology that causes both muscle atrophy and bone loss . The use of the short version space , as meaning 'the region beyond Earth's sky', predates

6600-557: The NMOS process, the COSMAC was implemented in CMOS form and used static logic . This allowed it to run at lower power settings and even be stopped completely; in addition it would run cooler and not generate as much heat as NMOS chips. RCA also produced radiation hardened versions, which found use in the aerospace field. These remain in production as of 2022, and as of 2008 continued to be produced by Renesas (formerly Intersil ). Successors to

6732-508: The background radiation from the Big Bang , is 2.7 kelvins (−270 °C; −455 °F). The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a kinetic temperature of millions of kelvins . Local concentrations of matter have condensed into stars and galaxies . Intergalactic space takes up most of

SECTION 50

#1732851064727

6864-471: The centrifugal acceleration due to the horizontal component of its velocity. For a low Earth orbit , this velocity is about 7,800 m/s (28,100 km/h; 17,400 mph); by contrast, the fastest piloted airplane speed ever achieved (excluding speeds achieved by deorbiting spacecraft) was 2,200 m/s (7,900 km/h; 4,900 mph) in 1967 by the North American X-15 . To achieve an orbit,

6996-500: The cosmic microwave background using satellites like the Wilkinson Microwave Anisotropy Probe . These observations indicate that the spatial geometry of the observable universe is " flat ", meaning that photons on parallel paths at one point remain parallel as they travel through space to the limit of the observable universe, except for local gravity. The flat universe, combined with the measured mass density of

7128-467: The immune system . Lesser symptoms include loss of body mass, nasal congestion, sleep disturbance, and puffiness of the face. During long-duration space travel, radiation can pose an acute health hazard . Exposure to high-energy, ionizing cosmic rays can result in fatigue, nausea, vomiting, as well as damage to the immune system and changes to the white blood cell count. Over longer durations, symptoms include an increased risk of cancer, plus damage to

7260-426: The zodiacal light . Interplanetary space contains the magnetic field generated by the Sun. There are magnetospheres generated by planets such as Jupiter, Saturn, Mercury and the Earth that have their own magnetic fields. These are shaped by the influence of the solar wind into the approximation of a teardrop shape, with the long tail extending outward behind the planet. These magnetic fields can trap particles from

7392-422: The 16 registers; however, the called subroutine must know (hard coded) what the calling PC register is to perform the "return" instruction. The SEP instruction is used to call a subroutine pointed to by one of the 16-bit registers and another SEP to return to the caller (SEP stands for Set Program Counter , and selects which one of the 16 registers is to be used as the program counter from that point onward). Before

7524-623: The 1802 are the CDP1804, CDP1805, and CDP1806, which have an extended instruction set, other enhanced features (like on-chip RAM and ROM, and built-in timer), with some versions running at faster clock speeds, though not a significant speed difference. Some features are also lost, like the DMA auto-boot loader functionality. There are also some minor pin function changes, but the line continues to be produced in its original 40-pin dual in-line package (DIP) format. Joseph Weisbecker had long been fascinated with

7656-484: The 1802's initial release, up until the collapse of RCA itself. These were mainly aimed at industrial applications and systems development, and were highly configurable. The COSMAC was unique among early 8-bit processors in that it had been explicitly designed for microcomputer use; other designs of the era were invariably aimed at the embedded processor space, and those that had been designed for computer use were generally more complex systems, and often 16-bit. Although

7788-402: The 1802, developed jointly by RCA and Sandia National Laboratories , was built on bulk silicon using C L (Closed COS/MOS Logic) technology. Along with its extreme low-power abilities, this makes the chip well-suited in space and military applications. (Also, at the time the 1802 was introduced, very few, if any, other radiation-hardened microprocessors were available in the market). The 1802

7920-696: The 1980s and 1990s used the 1802, amongst them: The first high-level language available for the 1802 was Forth , provided by Forth, Inc. and it was known as MicroFORTH, in 1976 (see Forth Inc's archive). Other available programming languages, both interpreters and compilers, are CHIP-8 (It was also invented by Joseph Weisbecker ) (and variants), 8th (a version of Forth created by Lee Hart), Tom Pittman's Tiny BASIC , C, various Assemblers and cross-assemblers, and others. Other specialty languages were used by federal agencies such as NASA and its installations, including Johnson Space Center, AMES, Goddard, Langley, Marshall, and Jet Propulsion Laboratory (JPL), which included

8052-554: The COSMAC had been designed for computer use, RCA's slow market entry and undersupported attempts in this market ultimately failed and other processors like the MOS 6502 and Zilog Z80 would come to dominate this market. Ironically, COSMAC would ultimately find great success in the embedded market, because its CMOS design allowed it to work at lower power. By the late 1970s it was widely used in many industrial settings, and especially aerospace. Multiple 1802s were used as auxiliary IO processors in

SECTION 60

#1732851064727

8184-421: The Earth's magnetosphere and the solar wind. The inner boundary is the ionosphere . The variable space-weather conditions of geospace are affected by the behavior of the Sun and the solar wind; the subject of geospace is interlinked with heliophysics —the study of the Sun and its impact on the planets of the Solar System. The day-side magnetopause is compressed by solar-wind pressure—the subsolar distance from

8316-570: The German experiment EXOSTACK, 30% of Bacillus subtilis spores survived the nearly 6 years exposure to outer space when embedded in salt crystals, whereas 80% survived in the presence of glucose , which stabilize the structure of the cellular macromolecules, especially during vacuum-induced dehydration. If shielded against solar UV , spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data may support

8448-570: The HAL/S cross-compiler, STOIC , a Forth-like language, and others. Interpreter for Process Structures (IPS), a programming language and development environment, was specifically written and used for real-time control of AMSAT satellites. The 1802 chip and computers using the microprocessor have been emulated and simulated in hardware and/or software by hobbyists. There are three designs in VHDL for an FPGA . A bus-accurate, full speed COSMAC Elf clone

8580-571: The I Register. The 4 Bits to the Right, sometimes called Low Order Hex Digit, are to do with the working Register, where Data is taken from, or put into it, and those 4 Bits are involved with the N Register. When a Program is being done, the various stages of the work and the Processes, are stored temporarily in the Register pointed to by the N Register, like what happens, when long Multiplication, or long Division,

8712-770: The LDEF Assembly and Transportation System to the Spacecraft Assembly and Encapsulation Facility – 2, where the LDEF project team led deintegration activities. Outer space Outer space (or simply space ) is the expanse that exists beyond Earth's atmosphere and between celestial bodies . It contains ultra-low levels of particle densities , constituting a near-perfect vacuum of predominantly hydrogen and helium plasma , permeated by electromagnetic radiation , cosmic rays , neutrinos , magnetic fields and dust . The baseline temperature of outer space, as set by

8844-533: The LDEF mission. Interstellar gases also would be trapped in an attempt to find clues into the formation of the Milky Way and the evolution of heavier elements. Some examples are investigation of exposure effects on: and physics in low gravity – e.g. crystal growth. At least one of the on-board experiments, the Thermal Control Surfaces Experiment (TCSE), used the RCA 1802 microprocessor. In

8976-444: The RX register and D accumulator. The EF and Q lines were typically used for multiple interfaces on 1802-based hobbyist computers because of the lines' favorable and easy handling. It was typical for the Q line to drive a status LED , a cassette interface, an RS-232 interface, and the speaker. This meant that the user could actually hear RS-232 and cassette data being transmitted (unless

9108-455: The SEP instruction, you can select any of the 16 registers to be the program counter ; using the SEX instruction, you can select any of the 16-bit registers to be the index register . Register R0 has the special use of holding the memory address for the built-in DMA controller. Register R1 has the special use of being the program counter for the interrupt handler. There are instructions that allow

9240-728: The Studio II was announced only in January 1977, a couple of months after the Fairchild Channel F became the first cartridge-based machine on the market. Both would soon be eclipsed and largely forgotten due to the release of the Atari 2600 later that year. RCA canceled the Studio II in February 1978. RCA also released a series of modular computer systems, based on the RCA Microboard form factor from

9372-452: The Sun. It is the space between the stars or stellar systems within a nebula or galaxy. Interstellar space contains an interstellar medium of sparse matter and radiation. The boundary between an astrosphere and interstellar space is known as an astropause . For the Sun, the astrosphere and astropause are called the heliosphere and heliopause. Approximately 70% of the mass of the interstellar medium consists of lone hydrogen atoms; most of

9504-732: The atmosphere to support itself, which he calculated to be at an altitude of about 83.8 km (52.1 mi). This distinguishes altitudes below as the region of aerodynamics and airspace , and above as the space of astronautics and free space . There is no internationally recognized legal altitude limit on national airspace, although the Kármán line is the most frequently used for this purpose. Objections have been made to setting this limit too high, as it could inhibit space activities due to concerns about airspace violations. It has been argued for setting no specified singular altitude in international law, instead applying different limits depending on

9636-498: The blood empties into the lungs to try to equalize the partial pressure gradient. Once the deoxygenated blood arrives at the brain, humans lose consciousness after a few seconds and die of hypoxia within minutes. Blood and other body fluids boil when the pressure drops below 6.3 kilopascals (1 psi), and this condition is called ebullism . The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Ebullism

9768-399: The body adjusts to the new environment. Longer-term exposure to weightlessness results in muscle atrophy and deterioration of the skeleton, or spaceflight osteopenia . These effects can be minimized through a regimen of exercise. Other effects include fluid redistribution, slowing of the cardiovascular system , decreased production of red blood cells , balance disorders, and a weakening of

9900-500: The case, in particular based on the craft and its purpose. Spacecraft have flown over foreign countries as low as 30 km (19 mi), as in the example of the Space Shuttle. The Outer Space Treaty provides the basic framework for international space law. It covers the legal use of outer space by nation states, and includes in its definition of outer space , the Moon, and other celestial bodies. The treaty states that outer space

10032-414: The center of the Earth is typically 10 Earth radii. On the night side, the solar wind stretches the magnetosphere to form a magnetotail that sometimes extends out to more than 100–200 Earth radii. For roughly four days of each month, the lunar surface is shielded from the solar wind as the Moon passes through the magnetotail. Geospace is populated by electrically charged particles at very low densities,

10164-417: The constant, each one followed by a Put instruction to the register, PHI and PLO). The two addressing modes Indirect register , and Indirect register with auto-increment are then fairly efficient, to perform 8-bit operations on the data in the accumulator. There are no other addressing modes, though. Thus, the direct addressing mode needs to be emulated using the four instructions mentioned earlier to load

10296-502: The contents of one register to another involves four instructions (one Get and one Put on the HI byte of the register, and a similar pair for the LO byte: GHI R1; PHI R2; GLO R1; PLO R2). Similarly, loading a new constant into a register (such as a new address for a subroutine jump, or the address of a data variable) also involves four instructions (two load immediate, LDI, instructions, one for each half of

10428-447: The continually expanding space. Matter that remained following the initial expansion has since undergone gravitational collapse to create stars, galaxies and other astronomical objects, leaving behind a deep vacuum that forms what is now called outer space. As light has a finite velocity, this theory constrains the size of the directly observable universe. The present day shape of the universe has been determined from measurements of

10560-406: The cosmic rays upon the shielding produces additional radiation that can affect the crew. Further research is needed to assess the radiation hazards and determine suitable countermeasures. The transition between Earth's atmosphere and outer space lacks a well-defined physical boundary, with the air pressure steadily decreasing with altitude until it mixes with the solar wind. Various definitions for

10692-448: The date is simply "soon after" the CMOS versions, and that plans for a single-chip version were already being planned. Although RCA began the development of the COSMAC in the early 1970s, it was some time before they introduced their own products based on it. In 1975, a prototype of an arcade game machine with swappable ROMs was experimented with for the coin-op business, but was ultimately abandoned. Meanwhile, Weisbecker had adapted

10824-450: The definition of outer space, the atmospheric density inside low-Earth orbital space, the first few hundred kilometers above the Kármán line, is still sufficient to produce significant drag on satellites. Geospace is a region of space that includes Earth's upper atmosphere and magnetosphere . The Van Allen radiation belts lie within the geospace. The outer boundary of geospace is the magnetopause , which forms an interface between

10956-468: The deploying astronauts next to the active grapple fixture. Engineers originally intended that the first mission would last about one year, and that several long-duration exposure missions would use the same frame. The exposure facility was actually used for a single 5.7-year mission. The LDEF facility was designed to glean information vital to the development of the Space Station Freedom (that

11088-422: The direction and speed of ions in the atmosphere were made from a sounding rocket . The altitude of 118 km (73.3 mi) above Earth was the midpoint for charged particles transitioning from the gentle winds of the Earth's atmosphere to the more extreme flows of outer space. The latter can reach velocities well over 268 m/s (880 ft/s). Spacecraft have entered into a highly elliptical orbit with

11220-452: The drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit . The concept that the space between the Earth and the Moon must be a vacuum was first proposed in the 17th century after scientists discovered that air pressure decreased with altitude. The immense scale of outer space was grasped in the 20th century when the distance to

11352-401: The early 1970s, built at his home using TTL components. RCA began development of the CMOS version of the processor design in 1973, sampling it in 1974 with plans to move to a single-chip implementation immediately. Jerry Herzog led the design of the single-chip version, which sampled in 1975 and entered production in 1976. In contrast to most designs of the era, which were fabricated using

11484-436: The eyes, nervous system , lungs and the gastrointestinal tract . On a round-trip Mars mission lasting three years, a large fraction of the cells in an astronaut's body would be traversed and potentially damaged by high energy nuclei. The energy of such particles is significantly diminished by the shielding provided by the walls of a spacecraft and can be further diminished by water containers and other barriers. The impact of

11616-466: The first known female commercial videogame developer. Weisbecker demonstrated the machine to RCA management throughout this period, but there was little interest at first. This was shortly after David Sarnoff had retired and handed the CEO role to his son, Robert Sarnoff . Robert was more interested in building the media side of the company while dating recording stars, ignoring RCA Laboratories in spite of

11748-500: The first on-board auto computer-based control systems. The 1802 was used in the manufacture of many pinball machines and video arcade games in Spain. A high-speed version of the 1802 was fabricated in Silicon on Sapphire (SOS) semiconductor process technology, which gives it a degree of resistance to radiation and electrostatic discharge (ESD). A different radiation-hardened version of

11880-479: The harsh environment, several life forms have been found that can withstand extreme space conditions for extended periods. Species of lichen carried on the ESA BIOPAN facility survived exposure for ten days in 2007. Seeds of Arabidopsis thaliana and Nicotiana tabacum germinated after being exposed to space for 1.5 years. A strain of Bacillus subtilis has survived 559 days when exposed to low Earth orbit or

12012-596: The high energy range, the flux of electrons is only about 1% of that of protons. Cosmic rays can damage electronic components and pose a health threat to space travelers. Smells produced returning from low Earth orbit extravehicular activity have a burned/metallic odor, similar to the scent of arc welding fumes, resulting from oxygen in low Earth orbit around the ISS, which clings to suits and equipment. Other regions of space could have very different smells, like that of different alcohols in molecular clouds . Despite

12144-627: The instructions took 16 or 24 clock cycles to complete, the 1802 was not particularly fast. For comparison, the 6502 completes most instruction in 2 to 4 clock cycles, with the longest (official instruction) taking 7 cycles. Various suffixes to the CDP1802 part number denote technical specifications, including (A, B, & C) operating speed (3.2 MHz to 6.4 MHz), temperature (-40 °C to +85 °C, -55 °C to +125 °C), and voltage ranges (4V to 10.5V), package type (D, E, Q), and burn-in (X). These were somewhat standardized between

12276-610: The international co-operation in the peaceful uses of outer space and preventing an arms race in space. Four additional space law treaties have been negotiated and drafted by the UN's Committee on the Peaceful Uses of Outer Space . Still, there remains no legal prohibition against deploying conventional weapons in space, and anti-satellite weapons have been successfully tested by the USA, USSR, China, and in 2019, India. The 1979 Moon Treaty turned

12408-414: The interstellar medium, including the heavy elements previously formed within the star's core. The density of matter in the interstellar medium can vary considerably: the average is around 10 particles per m , but cold molecular clouds can hold 10 –10 per m . RCA 1802 The COSMAC (Complementary Symmetry Monolithic Array Computer) is an 8-bit microprocessor family introduced by RCA . It

12540-588: The jurisdiction of all heavenly bodies (including the orbits around such bodies) over to the international community. The treaty has not been ratified by any nation that currently practices human spaceflight. In 1976, eight equatorial states (Ecuador, Colombia, Brazil, The Republic of the Congo, Zaire, Uganda, Kenya, and Indonesia) met in Bogotá, Colombia: with their "Declaration of the First Meeting of Equatorial Countries", or

12672-442: The large pressure differential between inside and outside the chest. Even if the subject's airway is fully open, the flow of air through the windpipe may be too slow to prevent the rupture. Rapid decompression can rupture eardrums and sinuses, bruising and blood seep can occur in soft tissues, and shock can cause an increase in oxygen consumption that leads to hypoxia . As a consequence of rapid decompression, oxygen dissolved in

12804-719: The late 1970s, as well as the RCA Studio II video game console (one of the first consoles to use bitmapped graphics). The Edukit single-board computer trainer system, similar to an expanded COSMAC Elf , was offered by Modus Systems Ltd. in Britain in the early 1980s. Infinite Incorporated produced an 1802-based, S-100 bus expandable console computer trainer in the late 1970s called the UC1800, available assembled or in kit form. As part of 1802 retrocomputing hobbyist work, other computers have been built more recently (post-2000), including

12936-478: The likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis. The Space Exposed Experiment Developed for Students (SEEDS) allowed students the opportunity to grow control and experimental tomato seeds that had been exposed on LDEF comparing and reporting the results. 12.5 million seeds were flown, and students from elementary to graduate school returned 8000 reports to NASA. The L.A. Times misreported that

13068-404: The magnetic field and particle flux from the Sun. The distance and strength of the heliopause varies depending on the activity level of the solar wind. The heliopause in turn deflects away low-energy galactic cosmic rays, with this modulation effect peaking during solar maximum. The volume of interplanetary space is a nearly total vacuum, with a mean free path of about one astronomical unit at

13200-641: The microprocessor without affecting its operation. It has two separate 8-pin buses: an 8-bit bidirectional data bus and a time-multiplexed address bus , with the high-order and low-order 8-bits of the 16-bit address being accessed on alternate clock cycles. This contrasts with most designs of the era, like the MOS 6502 and Intel 8080 , which used a 16-bit address bus. The 1802 has a single bit , programmable and testable output port (Q), and four input pins that are directly tested by branch instructions (EF1-EF4). These pins allow simple input/output (I/O) tasks to be handled directly and easily programmed. Because

13332-406: The microprocessor's design) This setup allows R0 to be used for DMA and R1 to be used for Interrupts, if desired, allowing R7 through RF (hex) for general program usage. Because of the 16-bit address bus, and the 8-bit data bus, the sixteen general purpose registers are 16 bits wide, but the accumulator D-register is only 8 bits wide. The accumulator, therefore, tends to be a bottleneck. Transferring

13464-518: The most distant high-z sources, indicating the presence of magnetic fields. Outside a protective atmosphere and magnetic field, there are few obstacles to the passage through space of energetic subatomic particles known as cosmic rays. These particles have energies ranging from about 10   eV up to an extreme 10  eV of ultra-high-energy cosmic rays . The peak flux of cosmic rays occurs at energies of about 10  eV, with approximately 87% protons, 12% helium nuclei and 1% heavier nuclei. In

13596-525: The motions of which are controlled by the Earth's magnetic field . These plasmas form a medium from which storm-like disturbances powered by the solar wind can drive electrical currents into the Earth's upper atmosphere. Geomagnetic storms can disturb two regions of geospace, the radiation belts and the ionosphere. These storms increase fluxes of energetic electrons that can permanently damage satellite electronics, interfering with shortwave radio communication and GPS location and timing. Magnetic storms can be

13728-414: The opportunity to return to simpler systems. Inexpensive…microcomputers could open up vast new markets. Beginning in 1970, Weisbecker began the design of a small machine using RCA transistor-transistor logic (TTL) ICs to construct the processor. Other parts, switches and lamps and such, he had to buy from Radio Shack , deliberately spreading his purchases around four stores so no one would ask him why he

13860-403: The orbital distance of the Earth. This space is not completely empty, and is sparsely filled with cosmic rays, which include ionized atomic nuclei and various subatomic particles. There is gas, plasma and dust, small meteors , and several dozen types of organic molecules discovered to date by microwave spectroscopy . A cloud of interplanetary dust is visible at night as a faint band called

13992-592: The original FRED, known within RCA as System 00 by this time, using the new chipset to produce a greatly simplified single-board system known as then COSMAC ELF . Building instructions were described in an article in Popular Electronics magazine in 1976, and an expanded version with various upgrades in a second article in 1977. A unique feature of the ELF is that it did not require any read only memory (ROM) for startup, instead,

14124-478: The platform, including a quiz-style educational product in partnership with Random House , one of the many companies that had been picked up by RCA's buying sprees. After a year of discussion, the company eventually decided to release two mass-market products based on the platform, a kit computer known as the COSMAC VIP , and a game console known as the RCA Studio II . The machines had been available since 1975, but

14256-545: The potential for computers in the home, having stated as early as 1955 that he expected they would one day be built into practically every device. The technology of the era made small embedded computers impossible, but the introduction of the integrated circuit (IC) in the 1960s changed things dramatically. In 1974 he described the possibilities in an IEEE Computer article: For 20 years computer hardware has become increasingly complex, languages more devious, and operating systems less efficient. Now, microcomputers afford some of us

14388-483: The processor's direct memory access (DMA) system was used to read front-panel switches directly into memory. RCA debated whether to introduce pre-packaged versions of the ELF to the market. While they debated, further development led to a simplified machine combining the ELF with a new display driver chip, the CDP1861 , to produce a game console . During this time, Joyce was hired by RCA to write several videogames for

14520-895: The range 0 to 255 (hex FF). There is no relative branching. The short branch always jumps within the page that contains the address byte. Long branches use full 16-bit addressing to support the 64K memory address space, and are the only 3-byte instructions. Skip instructions increment the PC by one for the unconditional Short Skip, or two for the Long Skips. Only the Long Skip has conditional branching. The processor does not have standard subroutine CALL address and RET instructions, though they can be simulated. The 16-register design makes possible some interesting subroutine call and return mechanisms, though they are better suited to small programs than general purpose coding. A few commonly used subroutines can be called quickly by keeping their address in one of

14652-439: The remainder consists of helium atoms. This is enriched with trace amounts of heavier atoms formed through stellar nucleosynthesis . These atoms are ejected into the interstellar medium by stellar winds or when evolved stars begin to shed their outer envelopes such as during the formation of a planetary nebula . The cataclysmic explosion of a supernova propagates shock waves of stellar ejecta outward, distributing it throughout

14784-497: The retrieval mission first to 1986, then indefinitely due to the Challenger disaster . After 5.7 years its orbit had decayed to about 175 nautical miles (324 km) and it was likely to burn up on reentry in a little over a month. It was finally recovered by Columbia on mission STS-32 on January 12, 1990. Columbia approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust. While LDEF

14916-640: The same as the partial pressure of oxygen at the Earth's surface. This pressure is high enough to prevent ebullism, but evaporation of nitrogen dissolved in the blood could still cause decompression sickness and gas embolisms if not managed. Humans evolved for life in Earth gravity , and exposure to weightlessness has been shown to have deleterious effects on human health. Initially, more than 50% of astronauts experience space motion sickness . This can cause nausea and vomiting, vertigo , headaches, lethargy , and overall malaise. The duration of space sickness varies, but it typically lasts for 1–3 days, after which

15048-468: The solar wind and other sources, creating belts of charged particles such as the Van Allen radiation belts. Planets without magnetic fields, such as Mars, have their atmospheres gradually eroded by the solar wind. Interstellar space is the physical space outside of the bubbles of plasma known as astrospheres , formed by stellar winds originating from individual stars, or formed by solar wind emanating from

15180-625: The space around just about every class of celestial object. Star formation in spiral galaxies can generate small-scale dynamos , creating turbulent magnetic field strengths of around 5–10 μ G . The Davis–Greenstein effect causes elongated dust grains to align themselves with a galaxy's magnetic field, resulting in weak optical polarization . This has been used to show ordered magnetic fields that exist in several nearby galaxies. Magneto-hydrodynamic processes in active elliptical galaxies produce their characteristic jets and radio lobes . Non-thermal radio sources have been detected even among

15312-409: The starting point of deep-space from, "That which lies beyond the orbit of the moon," to "That which lies beyond the farthest reaches of the Solar System itself." The International Telecommunication Union responsible for radio communication , including with satellites, defines deep-space as, "distances from the Earth equal to, or greater than, 2 million km (1.2 million mi)," which

15444-407: The throat and lungs boil away. More specifically, exposed bodily liquids such as saliva, tears, and liquids in the lungs boil away. Hence, at this altitude, human survival requires a pressure suit, or a pressurized capsule. Out in space, sudden exposure of an unprotected human to very low pressure , such as during a rapid decompression, can cause pulmonary barotrauma —a rupture of the lungs, due to

15576-427: The universe and the accelerating expansion of the universe , indicates that space has a non-zero vacuum energy , which is called dark energy . Estimates put the average energy density of the present day universe at the equivalent of 5.9 protons per cubic meter, including dark energy, dark matter, and baryonic matter (ordinary matter composed of atoms). The atoms account for only 4.6% of the total energy density, or

15708-478: The use of full term "outer space", with the earliest recorded use of this meaning in an epic poem by John Milton called Paradise Lost , published in 1667. The term outward space existed in a poem from 1842 by the English poet Lady Emmeline Stuart-Wortley called "The Maiden of Moscow", but in astronomy the term outer space found its application for the first time in 1845 by Alexander von Humboldt . The term

15840-410: The values in these registers to be set and read via D, separately working the upper and lower 8-bits at a time. There are also instructions to perform increment and decrement of the entire 16-bit value, and a few instructions perform automatic increment and decrement, like LDA (load advance) and STXD (store via X and decrement). 16-bit register and value comparisons would also need to use the D register as

15972-573: The various source suppliers, including RCA, Intersil, Harris, Hughes Aircraft, and Solid State Scientific (SSS). Hughes used the HCMP prefix, and SSS used the SCP (and possibly BCP) prefix, instead of CDP, and had additional suffixes that have not been documented as of yet. (examples: CDP1802A, CDP1802ACE, CDP1802BCD, HCMP1802AP, SCP1802D) The 1802 is an 8-bit byte machine, with minimal support for 16-bit operations, except via 2-byte manipulation. The primary accumulator

16104-399: The volume of the universe , but even galaxies and star systems consist almost entirely of empty space. Most of the remaining mass-energy in the observable universe is made up of an unknown form, dubbed dark matter and dark energy . Outer space does not begin at a definite altitude above Earth's surface. The Kármán line , an altitude of 100 km (62 mi) above sea level ,

16236-575: Was a 12 sided prism (to fit the shuttle orbiter payload bay), and made entirely from stainless steel . There were 5 or 6 experiments on each of the 12 long sides and a few more on the ends. It was designed to fly with one end facing earth and the other away from earth. Attitude control of LDEF was achieved with gravity-gradient stabilization and inertial distribution to maintain three-axis stability in orbit. Therefore, propulsion or other attitude control systems were not required, making LDEF free of acceleration forces and contaminants from jet firings. There

16368-504: Was also a magnetic/viscous damper to stop any initial oscillation after deployment. It had two grapple fixtures . An FRGF and an active (rigidize sensing) grapple used to send an electronic signal to initiate the 19 experiments that had electrical systems. This activated the Experiment Initiate System (EIS) which sent 24 initiation signals to the 20 active experiments. There were six initiation indications which were visible to

16500-580: Was buying so many parts. The design was running in October 1971, containing 100 chips spread over multiple circuit boards . The result, which he called FRED, ostensibly for Flexible Recreational Educational Device, was packaged into a box that was not unlike the Altair 8800 of a few years later, with toggle switches on the front panel for input, lamps for output, and later adding a hex pad keyboard. Weisbecker added new features continually and by 1972 it had gained

16632-469: Was created without a CDP1802 microprocessor chip or CDP1861 video chip using PIC microcontrollers . An online simulator of the COSMAC Elf (enhanced) written in JavaScript runs in the user's browser with no need to download. The RCA 1802 has a static core CMOS design with no minimum clock frequency , so that it can be run at very low speeds and low power, including a clock frequency of zero to suspend

16764-513: Was eventually built as the International Space Station ) and other spacecraft, especially the reactions of various space building materials to radiation, extreme temperature changes and collisions with space matter. Some of the experiments had a cover that opened after deployment and was designed to close after about a year, e.g. , Space Environment Effects (M0006). There was no telemetry, but some active experiments recorded data on

16896-457: Was eventually popularized through the writings of H. G. Wells after 1901. Theodore von Kármán used the term of free space to name the space of altitudes above Earth where spacecrafts reach conditions sufficiently free from atmospheric drag, differentiating it from airspace , identifying a legal space above territories free from the sovereign jurisdiction of countries. " Spaceborne " denotes existing in outer space, especially if carried by

17028-415: Was intended to be reused, and redeployed with new experiments, perhaps every 18 months. but after the unintended extension of mission 1 the structure itself was treated as an experiment and intensively studied before being placed into storage. The STS-41-C crew of Challenger deployed LDEF on April 7, 1984, into a nearly circular orbit at an altitude of 257 nautical miles. The LDEF structure shape

17160-647: Was passed by the United Nations General Assembly in 1963 and signed in 1967 by the Union of Soviet Socialist Republics (USSR), the United States of America (USA), and the United Kingdom (UK). As of 2017, 105 state parties have either ratified or acceded to the treaty. An additional 25 states signed the treaty, without ratifying it. Since 1958, outer space has been the subject of multiple United Nations resolutions. Of these, more than 50 have been concerning

17292-543: Was still attached to the RMS arm, an extensive 4.5 hour survey photographed each individual experiment tray, as well as larger areas. Nevertheless, shuttle operations did contaminate experiments when concerns for human comfort out-weighed important LDEF mission goals. Columbia landed at Edwards Air Force Base on January 20, 1990. With LDEF still in its bay, Columbia was ferried back on the Shuttle Carrier Aircraft to

17424-564: Was used in many spacecraft and space science programs, experiments, projects and modules such as the Galileo spacecraft , Magellan , the Plasma Wave Analyzer instrument on ESA's Ulysses spacecraft, various Earth-orbiting satellites and satellites carrying amateur radio. The 1802 has also been verified from NASA source documentation to have been used in the Hubble Space Telescope . A number of British military items from

#726273