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Topic Review
Starlink (Satellite Constellation)
Starlink is a satellite constellation being constructed by American company SpaceX to provide satellite Internet access. The constellation will consist of thousands of mass-produced small satellites, working in combination with ground transceivers. SpaceX also plans to sell some of the satellites for military, scientific or exploratory purposes. (As of January 2020), SpaceX has deployed 182 satellites. They plan to deploy 60 more per Falcon 9 launch, with launches as often as every two weeks after late 2019. In total, nearly 12,000 satellites will be deployed by the mid-2020s, with a possible later extension to 42,000. The initial 12,000 satellites are planned to orbit in three orbital shells: first placing approximately 1,600 in a 550-kilometer-altitude (340 mi) shell, then approximately 2,800 Ku- and Ka-band spectrum satellites at 1,150 km (710 mi) and approximately 7,500 V-band satellites at 340 km (210 mi). Commercial operation could begin in 2020. Concerns have been raised about the long-term danger of space junk resulting from placing thousands of satellites in orbits above 1,000 kilometres (620 mi) and a possible impact on astronomy, although SpaceX is reportedly attempting to solve the issue. The total cost of the decade-long project to design, build and deploy the constellation was estimated by SpaceX in May 2018 to be about US$10 billion. Product development began in 2015, with the first two prototype test-flight satellites launched in February 2018. A second set of test satellites and the first large deployment of a piece of the constellation occurred on 24 May 2019 (UTC) when the first 60 operational satellites were launched. The SpaceX satellite development facility in Redmond, Washington, houses the Starlink research, development, manufacturing and on-orbit control operations.
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  • 11 Nov 2022
Topic Review
Type Certificate
A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (‘type’). It confirms that the aircraft is manufactured according to an approved design, and that the design ensures compliance with airworthiness requirements. For up to three seats, primary category aircraft, certification costs around US$1m, US$25m for a general aviation aircraft and hundreds of millions of dollars for a commercial aircraft; certification delays can cost millions of dollars and can decide a program's profitability.
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Topic Review
Online Pipeline Characterisation on Autonomous Underwater Vehicles
Nowadays, more frequently, it is necessary to perform underwater operations such as surveying an area or inspecting and intervening on industrial infrastructures such as offshore oil and gas rigs or pipeline networks. The use of Autonomous Underwater Vehicles (AUV) has grown as a way to automate these tasks, reducing risks and execution time. One of the used sensing modalities is vision, providing RGB high-quality information in the mid to low range, making it appropriate for manipulation or detail inspection tasks. This research presents the use of a deep neural network to perform pixel-wise 3D segmentation of pipes and valves on underwater point clouds generated using a stereo pair of cameras. In addition, two novel algorithms are built to extract information from the detected instances, providing pipe vectors, gripping points, the position of structural elements such as elbows or connections, and valve type and orientation. The neural network and information algorithms are implemented on an AUV and executed in real-time, validating that the output information stream frame rate of 0.72 fps is high enough to perform manipulation tasks and to ensure full seabed coverage during inspection tasks. The used dataset, along with a trained model and the information algorithms, are provided to the scientific community.
  • 540
  • 11 Nov 2022
Topic Review
Fault Types and Effects of HVDC Transmission Systems
High voltage direct current (HVDC) transmission systems play a critical role to optimize resource allocation and stabilize power grid operation in the current power grid thanks to their asynchronous networking and large transmission capacity. To ensure the operation reliability of the power grid and reduce the outage time, it is imperative to realize fault diagnosis of HVDC transmission systems in a short time. 
  • 6.0K
  • 11 Nov 2022
Topic Review
Mooring (Watercraft)
A mooring refers to any permanent structure to which a vessel may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An anchor mooring fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, mooring refers to the act of attaching a vessel to a mooring. The term likely stems from the Dutch verb meren (to moor), used in English since the end of the 15th century.
  • 606
  • 10 Nov 2022
Topic Review
Rigid-Hulled Inflatable Boat
A rigid-hulled inflatable boat (RHIB) or rigid-inflatable boat (RIB) is a lightweight but high-performance and high-capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale. The design is stable and seaworthy. The inflatable collar allows the vessel to maintain buoyancy if a large quantity of water is shipped aboard due to bad sea conditions. The RIB is a development of the inflatable boat. Uses include work boats (supporting shore facilities or larger ships) in trades that operate on the water, military craft, where they are used in patrol roles and to transport troops between vessels or ashore, and lifeboats.
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Topic Review
ITS Launch Vehicle
The ITS launch vehicle was a 2016-2017 design for a privately funded orbital launch vehicle planned to be developed by SpaceX. Design work was discontinued in 2017 when development was shifted to a smaller version, now called BFR. The initial design objective of the ITS launch vehicle was to launch a variety of SpaceX Interplanetary Transport System missions to Mars and other destinations in the beyond-Earth-orbit portion of the Solar System. The first launch was not expected before the 2020s. The ITS launch vehicle was to be operated as a somewhat unusual two-stage rocket. Its first stage was to have been powered by 42 Raptor rocket engines—designed and manufactured by SpaceX—operating on densified (chilled near triple point) methane/oxygen, propellants that have not been widely used as rocket propellants in the past. Like the Falcon 9 orbital launch vehicle that preceded it, the ITS launch vehicle's first stage design was intended to be reusable, following a return to the launch site and vertical landing following each launch. When announced, it was also designed to have a new feature for SpaceX launch vehicles: full reusability of even the second-stage and orbital spacecraft as well. The large payload capacity of the launch vehicle placed it into the super-heavy lift class, with the ability to place 300 tonnes (660,000 lb) into low Earth orbit in reusable configuration and 550 tonnes (1,210,000 lb) in expendable mode. The second stage of the Earth launch vehicle was planned to have two versions, the Interplanetary spaceship for passengers and cargo and the ITS tanker to deliver propellants to Earth orbit. Both were to be powered by six vacuum-optimized Raptor rocket engines with three additional sea-level-nozzle Raptor engines for maneuvering. Thus, the element of the launch vehicle that was to provide second-stage acceleration to orbital velocity on all launches from Earth would also be used as an on-orbit spacecraft. The Interplanetary spaceship was planned as a very long-duration carrier of both passengers and space cargo to interplanetary destinations, and was to have served as both a descent and ascent vehicle at Mars. The high-level specifications for the vehicle were publicly announced in September 2016, but by July 2017, SpaceX had stated they would not build the 12 m (39 ft)-diameter vehicles as previously planned, but would instead build a "still large" but much smaller launch vehicle first. Subsequently, that was revealed to be the BFR in September 2017, a vehicle intended to cost-effectively replace and supersede all existing SpaceX launch vehicles and passenger/cargo spacecraft.
  • 668
  • 10 Nov 2022
Topic Review
Atom (System on Chip)
Atom is a system on a chip (SoC) platform designed for smartphones and tablet computers, launched by Intel in 2012. It is a continuation of the partnership announced by Intel and Google on September 13, 2011 to provide support for the Android operating system on Intel x86 processors. This range competes with existing SoCs developed for the smartphone and tablet market from companies such as Texas Instruments, Nvidia, Qualcomm and Samsung. Unlike these companies, which use ARM-based CPUs designed from the beginning to consume very low power, Intel has adapted the x86-based Intel Atom line of CPU developed for low power usage in netbooks, to even lower power usage. Since April 2012, several manufacturers have released Intel Atom-based tablets and phones as well as using the SoCs as a basis for other small form factor devices (e.g. mini PCs and stick PCs). In April 2016, Intel announced a major restructuring, including the cancellation of the SoFIA platform. It was reported by many news outlets that Broxton was cancelled.
  • 1.3K
  • 10 Nov 2022
Biography
Hugh Herr
Hugh Herr (born October 25, 1964) is an American rock climber, engineer, and biophysicist. The youngest of five siblings of a Mennonite family from Lancaster, Pennsylvania, Hugh Herr was a prodigy rock climber: by age eight, he had scaled the face of the 11,627-foot (3,544 m) Mount Temple in the Canadian Rockies, and by 17 he was acknowledged to be one of the best climbers in the United Stat
  • 1.4K
  • 10 Nov 2022
Topic Review
Proposed SLS and Orion Missions
NASA's new Space Launch System (SLS) and Orion programs will allow for beyond low-Earth orbit spaceflight. There are a number of notional, proposed missions for the programs, none of which are confirmed.
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