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Cluster (spacecraft)
Ariane flight V88 was the failed maiden flight of the Arianespace Ariane 5 rocket, vehicle no. 501, on 4 June 1996. It carried the Cluster spacecraft, a constellation of four European Space Agency research satellites. The launch ended in failure due to multiple errors in the software design: dead code, intended only for Ariane 4, with inadequate protection against integer overflow led to an exception handled inappropriately, halting the whole otherwise unaffected inertial navigation system. This caused the rocket to veer off its flight path 37 seconds after launch, beginning to disintegrate under high aerodynamic forces, and finally self-destructing via its automated flight termination system. The failure has become known as one of the most infamous and expensive software bugs in history. The failure resulted in a loss of more than US$370 million. Launch failure The Ariane 5 reused the code from the inertial reference platform from the Ariane 4, but the early part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Space Agency Science Programme
The Science Programme of the European Space Agency is a long-term programme of space science and space exploration missions. Managed by the agency's Directorate of Science, The programme funds the development, launch, and operation of missions led by European space agencies and institutions through generational campaigns. Horizon 2000, the programme's first campaign, facilitated the development of eight missions between 1985 and 1995 including four "cornerstone missions" – SOHO and Cluster II, XMM-''Newton'', ''Rosetta'', and '' Herschel''. Horizon 2000 Plus, the programme's second campaign, facilitated the development of ''Gaia'', LISA Pathfinder, and ''BepiColombo'' between 1995 and 2005. The programme's current campaign since 2005, Cosmic Vision, has so far funded the development of ten missions including three flagship missions, JUICE, Athena, and LISA. The programme's upcoming fourth campaign, Voyage 2050, is currently being drafted. Collaboration with agencies and insti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cluster II (spacecraft)
Cluster II is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of nearly two solar cycles. The mission is composed of four identical spacecraft flying in a tetrahedral formation. As a replacement for the original Cluster spacecraft which were lost in a launch failure in 1996, the four Cluster II spacecraft were successfully launched in pairs in July and August 2000 onboard two Soyuz-Fregat rockets from Baikonur, Kazakhstan. In February 2011, Cluster II celebrated 10 years of successful scientific operations in space. , its mission has been extended until the end of 2022. China National Space Administration/ESA Double Star mission operated alongside Cluster II from 2004 to 2007. Mission overview The four identical Cluster II satellites study the impact of the Sun's activity on the Earth's space environment by flying in formation around Earth. For the first time in space history, this mission is able to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariane 501 Cluster
Ariane may refer to: *Ariana (name), also Ariane, Arianne Arts * ''Ariane'' (Martinů), an opera by Bohuslav Martinů, first performed 1961 * ''Ariane'' (Massenet), an opera by Jules Massenet, first performed 1906 * ''Ariane'' (film), a 1931 German film directed by Paul Czinner * Ariane Films, a former French film production company * ''Ariane'', a play by Thomas Corneille (1625–1709) * ''Ariane'', the name of the 1957 film '' Love in the Afternoon'' in French speaking markets Transportation * Simca Ariane, a French car by Simca, 1957–1963 * Ariane (automobile), a French car by Automobiles Ariane, 1907 * French ship ''Ariane'', the name of several French ships * Ariane (rocket family), European rockets operated by Arianespace Other uses * Ariane (apple), an apple cultivar * 1225 Ariane, an asteroid * Tour Ariane (Ariane Tower), an office building west of Paris See also *Ariadna (other) *Ariadne (other) *Arianna (other) *Ariana (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Kahan
William "Velvel" Morton Kahan (born June 5, 1933) is a Canadian mathematician and computer scientist, who received the Turing Award in 1989 for "''his fundamental contributions to numerical analysis''", was named an ACM Fellow in 1994, and inducted into the National Academy of Engineering in 2005. Biography Born to a Canadian Jewish family, he attended the University of Toronto, where he received his bachelor's degree in 1954, his master's degree in 1956, and his Ph.D. in 1958, all in the field of mathematics. Kahan is now emeritus professor of mathematics and of electrical engineering and computer sciences (EECS) at the University of California, Berkeley. Kahan was the primary architect behind the IEEE 754-1985 standard for floating-point computation (and its radix-independent follow-on, IEEE 854). He has been called "The Father of Floating Point", since he was instrumental in creating the original IEEE 754 specification. Kahan continued his contributions to the IEEE 754 revisio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcain (rocket Engine)
Vulcain is a family of European first stage rocket engines for Ariane 5 and the future Ariane 6. Its development began in 1988 and the first flight was completed in 1996. The updated version of the engine, Vulcain 2, was first successfully flown in 2005. Both members of the family use liquid oxygen/liquid hydrogen cryogenic fuel. The new version under development for Ariane 6 will be called Vulcain 2.1. History The Vulcain rocket engine is named in French for Vulcan, the ancient Roman god of fire. Its development, carried out by a European partnership, began in 1988 with the Ariane 5 rocket program. It first flew in 1996 powering the ill-fated flight 501 without being the cause of the disaster, and had its first successful flight in 1997 (flight 502). In 2002 the upgraded Vulcain 2 with 20% more thrust first flew on flight 157, although a problem with the engine turned the flight into a failure. The cause was due to flight loads being much higher than expected, as the inqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual Modular Redundancy
In reliability engineering, dual modular redundancy (DMR) is when components of a system are duplicated, providing redundancy in case one should fail. It is particularly applied to systems where the duplicated components work in parallel, particularly in fault-tolerant computer systems. A typical example is a complex computer system which has duplicated nodes, so that should one node fail, another is ready to carry on its work. DMR provides robustness to the failure of one component, and error detection in case instruments or computers that should give the same result give different results, but does not provide error correction, as ''which'' component is correct and which is malfunctioning cannot be automatically determined. There is an old adage to this effect, stating: "Never go to sea with two chronometers; take one or three." Meaning, if two chronometers contradict, a sailor may not know which one is reading correctly. A lockstep fault-tolerant machine uses replicated ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Exception
In computing and computer programming, exception handling is the process of responding to the occurrence of ''exceptions'' – anomalous or exceptional conditions requiring special processing – during the execution of a program. In general, an exception breaks the normal flow of execution and executes a pre-registered ''exception handler''; the details of how this is done depend on whether it is a hardware or software exception and how the software exception is implemented. Exception handling, if provided, is facilitated by specialized programming language constructs, hardware mechanisms like interrupts, or operating system (OS) inter-process communication (IPC) facilities like signals. Some exceptions, especially hardware ones, may be handled so gracefully that execution can resume where it was interrupted. Definition The definition of an exception is based on the observation that each procedure has a precondition, a set of circumstances for which it will terminate "normall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arithmetic Overflow
Arithmetic () is an elementary part of mathematics that consists of the study of the properties of the traditional operations on numbers—addition, subtraction, multiplication, division, exponentiation, and extraction of roots. In the 19th century, Italian mathematician Giuseppe Peano formalized arithmetic with his Peano axioms, which are highly important to the field of mathematical logic today. History The prehistory of arithmetic is limited to a small number of artifacts, which may indicate the conception of addition and subtraction, the best-known being the Ishango bone from central Africa, dating from somewhere between 20,000 and 18,000 BC, although its interpretation is disputed. The earliest written records indicate the Egyptians and Babylonians used all the elementary arithmetic operations: addition, subtraction, multiplication, and division, as early as 2000 BC. These artifacts do not always reveal the specific process used for solving problems, but the ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integer (computer Science)
In computer science, an integer is a datum of integral data type, a data type that represents some range of mathematical integers. Integral data types may be of different sizes and may or may not be allowed to contain negative values. Integers are commonly represented in a computer as a group of binary digits (bits). The size of the grouping varies so the set of integer sizes available varies between different types of computers. Computer hardware nearly always provides a way to represent a processor register or memory address as an integer. Value and representation The ''value'' of an item with an integral type is the mathematical integer that it corresponds to. Integral types may be ''unsigned'' (capable of representing only non-negative integers) or ''signed'' (capable of representing negative integers as well). An integer value is typically specified in the source code of a program as a sequence of digits optionally prefixed with + or −. Some programming languages allow oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signedness
In computing, signedness is a property of data types representing numbers in computer programs. A numeric variable is ''signed'' if it can represent both positive and negative numbers, and ''unsigned'' if it can only represent non-negative numbers (zero or positive numbers). As ''signed'' numbers can represent negative numbers, they lose a range of positive numbers that can only be represented with ''unsigned'' numbers of the same size (in bits) because roughly half the possible values are non-positive values, whereas the respective unsigned type can dedicate all the possible values to the positive number range. For example, a two's complement signed 16-bit integer can hold the values −32768 to 32767 inclusively, while an unsigned 16 bit integer can hold the values 0 to 65535. For this sign representation method, the leftmost bit (most significant bit) denotes whether the value is negative (0 for positive or zero, 1 for negative). In programming languages For most architect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integer (computer Science)
In computer science, an integer is a datum of integral data type, a data type that represents some range of mathematical integers. Integral data types may be of different sizes and may or may not be allowed to contain negative values. Integers are commonly represented in a computer as a group of binary digits (bits). The size of the grouping varies so the set of integer sizes available varies between different types of computers. Computer hardware nearly always provides a way to represent a processor register or memory address as an integer. Value and representation The ''value'' of an item with an integral type is the mathematical integer that it corresponds to. Integral types may be ''unsigned'' (capable of representing only non-negative integers) or ''signed'' (capable of representing negative integers as well). An integer value is typically specified in the source code of a program as a sequence of digits optionally prefixed with + or −. Some programming languages allow oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floating Point
In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can be represented as a base-ten floating-point number: 12.345 = \underbrace_\text \times \underbrace_\text\!\!\!\!\!\!^ In practice, most floating-point systems use base two, though base ten (decimal floating point) is also common. The term ''floating point'' refers to the fact that the number's radix point can "float" anywhere to the left, right, or between the significant digits of the number. This position is indicated by the exponent, so floating point can be considered a form of scientific notation. A floating-point system can be used to represent, with a fixed number of digits, numbers of very different orders of magnitude — such as the number of meters between galaxies or between protons in an atom. For this reason, floating-poin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
