Using COTS technology in space
The use of COTS-technology in the development of special applications is a proven means of reducing time and cost. The article discusses the experience of using COTS to create calculators of spacecraft operating aboard.
COTS (Commercial Off-The-Shelf - "ready to use") - technology means that a special approach is used to build special-purpose systems, according to which industrial computing modules are used, and crates, racks, switching units and cables are made in a special design and provide the required operating conditions (for example, resistance to climatic, vibration, acoustic and other impacts). COTS-technologies use ready-made hardware and software technologies of an open type, previously widely tested and / or standardized in the market of common industrial civil applications.
Historically, the COTS concept emerged as an initiative by the US Department of Defense and the defense ministries of several other Western countries who want to reduce their costs by reducing the share of expensive, unique solutions and technologies. For Russian developers now, in the face of increasing economic conditions and the imposition of sanctions, blocking access to defense and dual-use hardware components, this method of saving money on creating equipment with high technical characteristics is particularly relevant.
')
The general trend of building systems based on standardized COTS components has penetrated into the space industry. This was facilitated by the extremely rapid pace of space exploration, the complication of tasks being solved, the requirements for reducing the development time and modernization of systems, increasing their speed and reliability. At the moment, in space there are always a large number of habitable and uninhabited aircraft of various countries. This industry has become a powerful industry associated with research, production of new materials, defense and other relevant tasks [1].
In the "pieces of particles" cosmic radiation consists of 90% of protons (ie, Hydrogen ions), 7% of helium nuclei (alpha particles), ~ 1% heavier atoms and ~ 1% electrons. Well, the stars (including the sun), the galactic nuclei, the Milky Way - abundantly illuminate everything not only with visible light, but also with X-ray and gamma radiation. During flares in the sun - the radiation from the sun increases 1000-1'000'000 times, which can be a serious problem (both for people of the future and current spacecraft outside the earth’s magnetosphere).
There are 2 charged particle belts around the earth - the so-called Van Allen radiation belts: at an altitude of ~ 4000 km from protons, and at an altitude of ~ 17 000 km from electrons. Particles there move in closed orbits, captured by the earth’s magnetic field. There is also a Brazilian magnetic anomaly - where the internal radiation belt comes closer to the ground, up to a height of 200 km.
When gamma and X-ray radiation (including secondary, obtained due to the collision of electrons with the body of the apparatus) passes through the microcircuit - charge begins to accumulate in the gate dielectric of the transistors, and the parameters of the transistors begin to slowly change - the threshold voltage of the transistors and leakage current. An ordinary civilian digital microcircuit after 5000 is happy can stop working normally (however, a person can stop working after 500-1000 is happy).
In a low orbit of 300-500km (where people fly), the annual dose may be 100 glad or less, respectively, even in 10 years the dialed dose will be tolerated by civilian chips. But in high orbits> 1000km the annual dose may be 10'000-20'000 happy, and the usual chips will gain a lethal dose in a matter of months.
The biggest problem of space electronics is the collision with heavy charged particles (CHP) - protons, alpha particles and high-energy ions. HRCs have such high energy that they “punch” the microcircuit through (together with the satellite body) and leave behind them a “train” of charge. At best, this can lead to a programming error (0 to become 1 or vice versa), at worst, it can lead to thyristor snapping. In the case of a latched chip, the power is shorted to ground, the current can go very large, and lead to the combustion of the microcircuit. If you have time to turn off the power and connect before burning - then everything will work as usual.
Heavy charged particles (TSR) of outer space, acting on integrated circuits (IC), can cause distortion of individual data bits or programs. The failure rate depends on the type of memory used, the parameters of the orbit, and the activity of the Sun.
There are several ways to deal with snapping:
1) Monitor the current consumption, and quickly distort the power.
2) Use chips on a sapphire substrate (Silicon-on-sapphire, SOS, more generally, Silicon-on-insulator, SOI) - this eliminates the formation of bipolar parasitic transistors and, accordingly, snapping. Software bugs however may still be. Silicon-on-sapphire plates are expensive, it is difficult to process them, and they have limited use in the civilian sector — accordingly, production is expensive.
3) Use the so-called triple-well process - it also greatly reduces the possibility of microcircuit snap-in due to additional isolation of transistors by pn-junction, but does not require any special plates or equipment and, accordingly, the production itself is much cheaper than silicon on sapphire.
Historically, in the USSR and Russia, they worked more on sapphire with silicon, and in the west they try to use ordinary silicon from triple-well as much as possible (to combine with commercial products and reduce costs), but SOS / SOI is also made of necessity.
In the case when memory space distorted the memory contents or the logic worked incorrectly because of the TZCH. Struggling with this remains only in architectural ways, for example:
- by the majority logic (when we connect 3 copies of each block we need at some distance from each other - then 2 correct answers “overload” one wrong one, using more error-resistant memory cells (out of 10 transistors, instead of the usual 6),
- using error correction codes in memory, cache and registers.
But it is impossible to get rid of errors completely, because it can happen that the TZCH (or rather, a whole fan of secondary particles) will pass exactly along the chip, and almost 5% of the chip may work with an error. Here you need a highly reliable system of several independent computers, and their correct programming.
As a result, the use of civilian microcircuits in space is limited by the snapping effect, and possibly at best in low orbits. In high orbits and in deep space, special radiation-resistant microcircuits are needed, since there we are deprived of the protection of the earth’s magnetic field, and the meter of lead will not save cosmic radiation from high-energy particles [2]. The scope of application of COTS-technology should be clearly outlined, their illegal use can lead to negative results.
Confirmation of the use of COTS technology and industrial ECB in space is the growing popularity of satellites made according to the CubeSat standard.
Kubsat, CubeSat - a format of small (ultra-small) artificial earth satellites for space exploration, having a volume of 1 liter and a mass of not more than 1.33 kg or several (multiple) more (Fig. 1).
Fig.1 Satellite of CubeSat standard of Dauria Aerospace company
Kubsaty usually use the CubeSat chassis framework specifications and purchased standard components - COTS electronics and other nodes. CubeSat specifications were developed in 1999 by California Polytechnic and Stanford universities to simplify the creation of ultra-small satellites.
The CubeSat specification includes standardized dimensions and architecture. All CubeSat are divided into dimensions of 1 unit (10 × 10 × 10 cm), 2U (10 × 10 × 20 cm), 3U (10 × 10 × 30 cm) and so on.
CubeSat standard does not limit the imagination of developers and engineering approaches for building spacecraft. Inside Kubsat there are no generally accepted assembly instructions, that is, universal standards describing information, mechanical or electrical interfaces. There are recommendations of the type of correspondence of the dimensions of electronic boards to the PC / 104 form factor, some approaches to the pinout of the contacts, information buses and power buses, but the specific implementation of each developer can be individual [3].
CubeSat satellites are being created from industrial-grade electronics, i.e. that which is intended for operation on Earth, and did not prepare for space. Despite this, the capabilities of modern chips allow them to work in seemingly unsuitable conditions. They may not be long-lived, but they ensure the operability of devices up to a year, or even several times more [4].
CompactPCI
Systems based on the CompactPCI standard incorporate a mechanical construct that allows installation of processor and peripheral modules in a passive cross-board with a standard defined by interconnects of data exchange between system modules. The characteristics of the constructs, types and topologies used by interconnects are well documented in the relevant standard developed by a consortium of international companies under the auspices of PICMG (www.picmg.org) (Fig. 2).
Fig.2 Principle of docking CompactPCI standard modules
The systems are built in the construction of Euromechanics 3U (Fig. 3), 6U
The main advantages of the CompactPCI standard:
- the possibility of building multiprocessor, heterogeneous computing systems;
- high resistance to shock and vibration;
- efficient cooling;
- support for hot swap mode;
- backup support;
- The use of standard chassis from different manufacturers.
Fig.3 Enclosure with CompactPCI modules
A good example of the reliability of systems implemented according to the CompactPCI standard is the control system of the Opportunity rover, which is controlled by two computers based on the CompactPCI standard [5].
Opportunity rover was landed on the red planet on January 24, 2004 and is still in operation.
The core of the control system is a single-board computer RAD6000 (manufactured by BAE Systems), made in Compact PCI 6U version 2.0.
The RAD6000 is a radiation-resistant single board computer based on the RISC processor, released by IBM. Later this division became part of BAE Systems.
The computer has a maximum clock frequency of 33 MHz and a speed of about 35 MIPS.
The board has 128 MB of RAM with ECC. Usually VxWorks RTOS is running on this computer. The processor frequency can be set to 2.5, 5, 10 or 20 MHz.
PC / 104
The PC / 104 form factor was adopted in 1992, in response to demands for a reduction in overall dimensions and power consumption for computer systems. Each of these goals was achieved without reducing hardware and software compatibility with popular computer standards. The PC104 specification offers full architectural, hardware, and software compatibility with computer standards in compact 3.6 "x3.8" board sizes (91.44 mm x 96.52 mm). The name of the standard was obtained due to the use of a 104-pin ISA bus located at the bottom of the board (Fig. 4).
Fig.4. Stack of PC / 104 modules
PC / 104 standards describe the modular principle of building compact embedded systems in the form of a column of boards mated to each other. The standards of the PC / 104 family have proven themselves among the developers of compact on-board computer systems. Many engineers choose the PC / 104 because of the advantages that give the small weight and dimensions of such devices, the mechanical reliability of both the connectors and the structure as a whole.
The PC / 104 family of standards describes the exchange of data between modules on parallel ISA buses of 16 bits, PCI 32 bits and using serial PCI-Express, USB 2.0 and SATA interconnects and consists of 5 specifications. In addition to the most compact size of 90 × 96 mm, the family of standards includes the form factors EPIC and EBX.
One example of application is the use of PC / 104 format modules for building equipment for the Terminator space experiment. In the framework of the space experiment, observations were made in the visible and near-IR spectral ranges of layered formations at the heights of the upper mesosphere - the lower thermosphere in the vicinity of the solar terminator ”(Fig. 5).
Fig. 5 - ON "Terminator".
The core of the electronics unit is a CPC1600 processor board (Fastwel manufacturer)
MicroPC
MicroPC is an IBM PC-compatible (x86) industrial computer form factor for harsh environments.
The size of MicroPC boards is 124 × 112 mm. Thanks to the original concept of developing products, the MicroPC standard is one of the most resistant to harsh external factors on the embedded computer market. MicroPC modules allow you to quickly build low-cost, highly reliable embedded systems and automation systems from ready-made bricks (Fig. 6).
Fig.6 Chassis with MicroPC format modules
Design feature:
• passive motherboard (backplane or cable);
• 4-point mounting expansion boards;
• it is possible to have additional discrete and analog I / O ports or PC / 104 expansion for processor modules;
• watchdog;
• extended temperature range: from −40 to +85 ° C;
• low power consumption and heat generation.
A prime example of the use of MicroRS format modules in space is the NEPTUN-ME cosmonaut console of the manned transport vehicle SOYUZ TMA-M.
At present, crews are delivered to a near-earth orbit by means of manned transport vehicles of the Soyuz TMA-M series, which are modifications of the Soyuz TMA vehicles. The ships are equipped with new generation cosmonauts consoles - “Neptun-ME” (Fig. 7), developed by NIIAO. The console is a three-processor computing system that includes two channels for displaying information on the basis of matrix liquid crystal indicators, means of exchange with onboard systems of the ship, and manual controls of the onboard complex.
Fig.7 The “Neptun-ME” console of the Soyuz TMA spacecraft.
The cosmonauts "Neptun-ME" remote control panel is designed for monitoring and operational control of crew members onboard spacecraft systems.
Technical means were developed and selected taking into account the requirements of working capacity in conditions of weightlessness and depressurization of the descent vehicle, i.e. taking into account the work of astronauts in a spacesuit.
The computing part is built using MicroPC modules. [6].
Conclusion
Using COTS allows you to quickly develop a product in a highly competitive environment. As the examples have shown, COTS is used not only in Western development companies, but also in the Russian Federation.
COTS allow you to create competitive computing systems. This technology is a guarantee of long-term success, ensuring the application of the latest global business trends and engineering achievements in the field of modern embedded computer technology.
Literature
1. SpaceVPX - space reliability of trunk – modular systems, ICA: VCS ı2 / 2016
2. Microelectronics for space and military. Electronic resource
3. Caution, cubsat! Electronic resource
4. When the cubs got big. Electronic resource
5. CompactPCI - the standard for the construction of space computing. STA number 1/2017. Pp. 30-31.
6. Integrated SOI of the Soyuz-TMA spacecraft and the manual control loop of the Russian segment of the ISS Alpha. Electronic resource .
COTS (Commercial Off-The-Shelf - "ready to use") - technology means that a special approach is used to build special-purpose systems, according to which industrial computing modules are used, and crates, racks, switching units and cables are made in a special design and provide the required operating conditions (for example, resistance to climatic, vibration, acoustic and other impacts). COTS-technologies use ready-made hardware and software technologies of an open type, previously widely tested and / or standardized in the market of common industrial civil applications.
Historically, the COTS concept emerged as an initiative by the US Department of Defense and the defense ministries of several other Western countries who want to reduce their costs by reducing the share of expensive, unique solutions and technologies. For Russian developers now, in the face of increasing economic conditions and the imposition of sanctions, blocking access to defense and dual-use hardware components, this method of saving money on creating equipment with high technical characteristics is particularly relevant.
')
The general trend of building systems based on standardized COTS components has penetrated into the space industry. This was facilitated by the extremely rapid pace of space exploration, the complication of tasks being solved, the requirements for reducing the development time and modernization of systems, increasing their speed and reliability. At the moment, in space there are always a large number of habitable and uninhabited aircraft of various countries. This industry has become a powerful industry associated with research, production of new materials, defense and other relevant tasks [1].
How does the radiation on the chip
In the "pieces of particles" cosmic radiation consists of 90% of protons (ie, Hydrogen ions), 7% of helium nuclei (alpha particles), ~ 1% heavier atoms and ~ 1% electrons. Well, the stars (including the sun), the galactic nuclei, the Milky Way - abundantly illuminate everything not only with visible light, but also with X-ray and gamma radiation. During flares in the sun - the radiation from the sun increases 1000-1'000'000 times, which can be a serious problem (both for people of the future and current spacecraft outside the earth’s magnetosphere).
There are 2 charged particle belts around the earth - the so-called Van Allen radiation belts: at an altitude of ~ 4000 km from protons, and at an altitude of ~ 17 000 km from electrons. Particles there move in closed orbits, captured by the earth’s magnetic field. There is also a Brazilian magnetic anomaly - where the internal radiation belt comes closer to the ground, up to a height of 200 km.
When gamma and X-ray radiation (including secondary, obtained due to the collision of electrons with the body of the apparatus) passes through the microcircuit - charge begins to accumulate in the gate dielectric of the transistors, and the parameters of the transistors begin to slowly change - the threshold voltage of the transistors and leakage current. An ordinary civilian digital microcircuit after 5000 is happy can stop working normally (however, a person can stop working after 500-1000 is happy).
In a low orbit of 300-500km (where people fly), the annual dose may be 100 glad or less, respectively, even in 10 years the dialed dose will be tolerated by civilian chips. But in high orbits> 1000km the annual dose may be 10'000-20'000 happy, and the usual chips will gain a lethal dose in a matter of months.
The biggest problem of space electronics is the collision with heavy charged particles (CHP) - protons, alpha particles and high-energy ions. HRCs have such high energy that they “punch” the microcircuit through (together with the satellite body) and leave behind them a “train” of charge. At best, this can lead to a programming error (0 to become 1 or vice versa), at worst, it can lead to thyristor snapping. In the case of a latched chip, the power is shorted to ground, the current can go very large, and lead to the combustion of the microcircuit. If you have time to turn off the power and connect before burning - then everything will work as usual.
Heavy charged particles (TSR) of outer space, acting on integrated circuits (IC), can cause distortion of individual data bits or programs. The failure rate depends on the type of memory used, the parameters of the orbit, and the activity of the Sun.
There are several ways to deal with snapping:
1) Monitor the current consumption, and quickly distort the power.
2) Use chips on a sapphire substrate (Silicon-on-sapphire, SOS, more generally, Silicon-on-insulator, SOI) - this eliminates the formation of bipolar parasitic transistors and, accordingly, snapping. Software bugs however may still be. Silicon-on-sapphire plates are expensive, it is difficult to process them, and they have limited use in the civilian sector — accordingly, production is expensive.
3) Use the so-called triple-well process - it also greatly reduces the possibility of microcircuit snap-in due to additional isolation of transistors by pn-junction, but does not require any special plates or equipment and, accordingly, the production itself is much cheaper than silicon on sapphire.
Historically, in the USSR and Russia, they worked more on sapphire with silicon, and in the west they try to use ordinary silicon from triple-well as much as possible (to combine with commercial products and reduce costs), but SOS / SOI is also made of necessity.
In the case when memory space distorted the memory contents or the logic worked incorrectly because of the TZCH. Struggling with this remains only in architectural ways, for example:
- by the majority logic (when we connect 3 copies of each block we need at some distance from each other - then 2 correct answers “overload” one wrong one, using more error-resistant memory cells (out of 10 transistors, instead of the usual 6),
- using error correction codes in memory, cache and registers.
But it is impossible to get rid of errors completely, because it can happen that the TZCH (or rather, a whole fan of secondary particles) will pass exactly along the chip, and almost 5% of the chip may work with an error. Here you need a highly reliable system of several independent computers, and their correct programming.
As a result, the use of civilian microcircuits in space is limited by the snapping effect, and possibly at best in low orbits. In high orbits and in deep space, special radiation-resistant microcircuits are needed, since there we are deprived of the protection of the earth’s magnetic field, and the meter of lead will not save cosmic radiation from high-energy particles [2]. The scope of application of COTS-technology should be clearly outlined, their illegal use can lead to negative results.
Examples of the use of COTS technology in space
Confirmation of the use of COTS technology and industrial ECB in space is the growing popularity of satellites made according to the CubeSat standard.
Kubsat, CubeSat - a format of small (ultra-small) artificial earth satellites for space exploration, having a volume of 1 liter and a mass of not more than 1.33 kg or several (multiple) more (Fig. 1).
Fig.1 Satellite of CubeSat standard of Dauria Aerospace company
Kubsaty usually use the CubeSat chassis framework specifications and purchased standard components - COTS electronics and other nodes. CubeSat specifications were developed in 1999 by California Polytechnic and Stanford universities to simplify the creation of ultra-small satellites.
The CubeSat specification includes standardized dimensions and architecture. All CubeSat are divided into dimensions of 1 unit (10 × 10 × 10 cm), 2U (10 × 10 × 20 cm), 3U (10 × 10 × 30 cm) and so on.
CubeSat standard does not limit the imagination of developers and engineering approaches for building spacecraft. Inside Kubsat there are no generally accepted assembly instructions, that is, universal standards describing information, mechanical or electrical interfaces. There are recommendations of the type of correspondence of the dimensions of electronic boards to the PC / 104 form factor, some approaches to the pinout of the contacts, information buses and power buses, but the specific implementation of each developer can be individual [3].
CubeSat satellites are being created from industrial-grade electronics, i.e. that which is intended for operation on Earth, and did not prepare for space. Despite this, the capabilities of modern chips allow them to work in seemingly unsuitable conditions. They may not be long-lived, but they ensure the operability of devices up to a year, or even several times more [4].
Other COTS standards
CompactPCI
Systems based on the CompactPCI standard incorporate a mechanical construct that allows installation of processor and peripheral modules in a passive cross-board with a standard defined by interconnects of data exchange between system modules. The characteristics of the constructs, types and topologies used by interconnects are well documented in the relevant standard developed by a consortium of international companies under the auspices of PICMG (www.picmg.org) (Fig. 2).
Fig.2 Principle of docking CompactPCI standard modules
The systems are built in the construction of Euromechanics 3U (Fig. 3), 6U
The main advantages of the CompactPCI standard:
- the possibility of building multiprocessor, heterogeneous computing systems;
- high resistance to shock and vibration;
- efficient cooling;
- support for hot swap mode;
- backup support;
- The use of standard chassis from different manufacturers.
Fig.3 Enclosure with CompactPCI modules
A good example of the reliability of systems implemented according to the CompactPCI standard is the control system of the Opportunity rover, which is controlled by two computers based on the CompactPCI standard [5].
Opportunity rover was landed on the red planet on January 24, 2004 and is still in operation.
The core of the control system is a single-board computer RAD6000 (manufactured by BAE Systems), made in Compact PCI 6U version 2.0.
The RAD6000 is a radiation-resistant single board computer based on the RISC processor, released by IBM. Later this division became part of BAE Systems.
The computer has a maximum clock frequency of 33 MHz and a speed of about 35 MIPS.
The board has 128 MB of RAM with ECC. Usually VxWorks RTOS is running on this computer. The processor frequency can be set to 2.5, 5, 10 or 20 MHz.
PC / 104
The PC / 104 form factor was adopted in 1992, in response to demands for a reduction in overall dimensions and power consumption for computer systems. Each of these goals was achieved without reducing hardware and software compatibility with popular computer standards. The PC104 specification offers full architectural, hardware, and software compatibility with computer standards in compact 3.6 "x3.8" board sizes (91.44 mm x 96.52 mm). The name of the standard was obtained due to the use of a 104-pin ISA bus located at the bottom of the board (Fig. 4).
Fig.4. Stack of PC / 104 modules
PC / 104 standards describe the modular principle of building compact embedded systems in the form of a column of boards mated to each other. The standards of the PC / 104 family have proven themselves among the developers of compact on-board computer systems. Many engineers choose the PC / 104 because of the advantages that give the small weight and dimensions of such devices, the mechanical reliability of both the connectors and the structure as a whole.
The PC / 104 family of standards describes the exchange of data between modules on parallel ISA buses of 16 bits, PCI 32 bits and using serial PCI-Express, USB 2.0 and SATA interconnects and consists of 5 specifications. In addition to the most compact size of 90 × 96 mm, the family of standards includes the form factors EPIC and EBX.
One example of application is the use of PC / 104 format modules for building equipment for the Terminator space experiment. In the framework of the space experiment, observations were made in the visible and near-IR spectral ranges of layered formations at the heights of the upper mesosphere - the lower thermosphere in the vicinity of the solar terminator ”(Fig. 5).
Fig. 5 - ON "Terminator".
The core of the electronics unit is a CPC1600 processor board (Fastwel manufacturer)
MicroPC
MicroPC is an IBM PC-compatible (x86) industrial computer form factor for harsh environments.
The size of MicroPC boards is 124 × 112 mm. Thanks to the original concept of developing products, the MicroPC standard is one of the most resistant to harsh external factors on the embedded computer market. MicroPC modules allow you to quickly build low-cost, highly reliable embedded systems and automation systems from ready-made bricks (Fig. 6).
Fig.6 Chassis with MicroPC format modules
Design feature:
• passive motherboard (backplane or cable);
• 4-point mounting expansion boards;
• it is possible to have additional discrete and analog I / O ports or PC / 104 expansion for processor modules;
• watchdog;
• extended temperature range: from −40 to +85 ° C;
• low power consumption and heat generation.
A prime example of the use of MicroRS format modules in space is the NEPTUN-ME cosmonaut console of the manned transport vehicle SOYUZ TMA-M.
At present, crews are delivered to a near-earth orbit by means of manned transport vehicles of the Soyuz TMA-M series, which are modifications of the Soyuz TMA vehicles. The ships are equipped with new generation cosmonauts consoles - “Neptun-ME” (Fig. 7), developed by NIIAO. The console is a three-processor computing system that includes two channels for displaying information on the basis of matrix liquid crystal indicators, means of exchange with onboard systems of the ship, and manual controls of the onboard complex.
Fig.7 The “Neptun-ME” console of the Soyuz TMA spacecraft.
The cosmonauts "Neptun-ME" remote control panel is designed for monitoring and operational control of crew members onboard spacecraft systems.
Technical means were developed and selected taking into account the requirements of working capacity in conditions of weightlessness and depressurization of the descent vehicle, i.e. taking into account the work of astronauts in a spacesuit.
The computing part is built using MicroPC modules. [6].
Conclusion
Using COTS allows you to quickly develop a product in a highly competitive environment. As the examples have shown, COTS is used not only in Western development companies, but also in the Russian Federation.
COTS allow you to create competitive computing systems. This technology is a guarantee of long-term success, ensuring the application of the latest global business trends and engineering achievements in the field of modern embedded computer technology.
Literature
1. SpaceVPX - space reliability of trunk – modular systems, ICA: VCS ı2 / 2016
2. Microelectronics for space and military. Electronic resource
3. Caution, cubsat! Electronic resource
4. When the cubs got big. Electronic resource
5. CompactPCI - the standard for the construction of space computing. STA number 1/2017. Pp. 30-31.
6. Integrated SOI of the Soyuz-TMA spacecraft and the manual control loop of the Russian segment of the ISS Alpha. Electronic resource .
Source: https://habr.com/ru/post/403217/
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