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TSS-1
A number of space tethers have been deployed in space missions. Tether satellites can be used for various purposes including research into tether propulsion, Gravity-gradient stabilization, tidal stabilisation and orbital plasma dynamics. The missions have met with varying degrees of success; a few have been highly successful. Description Tethered satellites are composed of three parts: the base-satellite; tether; and sub-satellite. The base-satellite contains the sub-satellite and tether until deployment. Sometimes the base-satellite is another basic satellite, other times it could be a spacecraft, space station, or the Moon. The tether is what keeps the two satellites connected. The sub-satellite is released from the base assisted by a spring ejection system, centrifugal force or gravity gradient effects. Tethers can be deployed for a range of applications, including electrodynamic propulsion, momentum exchange, artificial gravity, deployment of sensors or antennas etc. Tethe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-75
STS-75 was a 1996 NASA Space Shuttle mission, the 19th mission of the ''Columbia'' orbiter. Crew Allen, Hoffman, Nicollier and Chang-Díaz had previously been members of the STS-46 crew, which had flown the TSS-1 experiment in 1992. Mission objective Tethered Satellite System The primary objective of STS-75 was to carry the Tethered Satellite System Reflight (TSS-1R) into orbit and to deploy it spaceward on a conducting tether. The mission also flew the United States Microgravity Payload (USMP-3) designed to investigate materials science and condensed matter physics. The TSS-1R mission was a reflight of TSS-1 which was flown onboard Space Shuttle ''Atlantis'' on STS-46 in July/August 1992. The Tether Satellite System circled the Earth at an altitude of 296 kilometers, placing the tether system within the rarefied electrically charged layer of the atmosphere known as the ionosphere. STS-75 mission scientists hoped to deploy the tether to a distance of . Over 19 kilometers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-46 TSS-1
STS-46 was a NASA Space Shuttle mission using and was launched on July 31, 1992, and landed on August 8, 1992. Crew Backup crew Crew seating arrangements Mission highlights The mission's primary objectives were the deployment of the European Space Agency's European Retrievable Carrier (EURECA) and the joint NASA/ASI ( Italian Space Agency) Tethered Satellite System (TSS-1). EURECA was deployed a day later than scheduled because of a problem with its data handling system. Seven and a half hours after deployment, the spacecraft's thrusters were fired to boost EURECA to its planned operating altitude of around . However, thruster firing was cut to six minutes from twenty-four minutes because of unexpected attitude data from the spacecraft. The problem was resolved, and EURECA was successfully boosted to its operational orbit on the mission's sixth day. TSS-1 deployment also was delayed one day because of the problems with EURECA. During deployment, the satellite re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-46
STS-46 was a NASA Space Shuttle mission using and was launched on July 31, 1992, and landed on August 8, 1992. Crew Backup crew Crew seating arrangements Mission highlights The mission's primary objectives were the deployment of the European Space Agency's European Retrievable Carrier (EURECA) and the joint NASA/ASI (Italian Space Agency) Tethered Satellite System (TSS-1). EURECA was deployed a day later than scheduled because of a problem with its data handling system. Seven and a half hours after deployment, the spacecraft's thrusters were fired to boost EURECA to its planned operating altitude of around . However, thruster firing was cut to six minutes from twenty-four minutes because of unexpected attitude data from the spacecraft. The problem was resolved, and EURECA was successfully boosted to its operational orbit on the mission's sixth day. TSS-1 deployment also was delayed one day because of the problems with EURECA. During deployment, the satellite reach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italian Space Agency
The Italian Space Agency ( it, Agenzia Spaziale Italiana; ASI) is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy. The agency cooperates with numerous national and international entities who are active in aerospace research and technology. Nationally, ASI is responsible for both drafting the National Aerospace Plan and ensuring it is carried out. To do this the agency operates as the owner/coordinator of a number of Italian space research agencies and assets such as CIRA as well as organising the calls and opportunities process for Italian industrial contractors on spaceflight projects. Internationally, the ASI provides Italy's delegation to the Council of the European Space Agency and to its subordinate bodies as well as representing the country's interests in foreign collaborations. ASI's main headquarters are located in Rome, Italy, and the agency also has direct control over two operational centres: the Centre f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tether Propulsion
Space tethers are long cables which can be used for propulsion, momentum exchange, stabilization and attitude control, or maintaining the relative positions of the components of a large dispersed satellite/spacecraft sensor system. Depending on the mission objectives and altitude, spaceflight using this form of spacecraft propulsion is theorized to be significantly less expensive than spaceflight using rocket engines. Main techniques Tether satellites might be used for various purposes, including research into tether propulsion, tidal stabilization and orbital plasma dynamics. Five main techniques for employing space tethers are in development: ;Electrodynamic tethers Electrodynamic tethers are primarily used for propulsion. These are conducting tethers that carry a current that can generate either thrust or drag from a planetary magnetic field, in much the same way as an electric motor does. ;Momentum exchange tethers These can be either rotating tethers, or non-rotati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Tether
Space tethers are long cables which can be used for propulsion, momentum exchange, stabilization and attitude control, or maintaining the relative positions of the components of a large dispersed satellite/spacecraft sensor system. Depending on the mission objectives and altitude, spaceflight using this form of spacecraft propulsion is theorized to be significantly less expensive than spaceflight using rocket engines. Main techniques Tether satellites might be used for various purposes, including research into tether propulsion, tidal stabilization and orbital plasma dynamics. Five main techniques for employing space tethers are in development: ;Electrodynamic tethers Electrodynamic tethers are primarily used for propulsion. These are conducting tethers that carry a current that can generate either thrust or drag from a planetary magnetic field, in much the same way as an electric motor does. ;Momentum exchange tethers These can be either rotating tethers, or non-rotating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity-gradient Stabilization
Gravity-gradient stabilization (a.k.a. "tidal stabilization") is a method of stabilizing artificial satellites or space tethers in a fixed orientation using only the orbited body's mass distribution and gravitational field. The main advantage over using active stabilization with propellants, gyroscopes or reaction wheels is the low use of power and resources. It can also reduce or prevent the risk of propellant contamination of sensitive components. The idea is to use the Earth's gravitational field and tidal forces to keep the spacecraft aligned in the desired orientation. The gravity of the Earth decreases according to the inverse-square law, and by extending the long axis perpendicular to the orbit, the "lower" part of the orbiting structure will be more attracted to the Earth. The effect is that the satellite will tend to align its axis of minimum moment of inertia vertically. The first experimental attempt to use the technique on a human spaceflight was performed on Sep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Atlantis
Space Shuttle ''Atlantis'' (Orbiter Vehicle designation: OV‑104) is a Space Shuttle orbiter vehicle which belongs to NASA, the spaceflight and space exploration agency of the United States. ''Atlantis'' was manufactured by the Rockwell International company in Southern California and was delivered to the Kennedy Space Center in Eastern Florida in April 1985. ''Atlantis'' is also the fourth operational and the second-to-last Space Shuttle built. Its maiden flight was STS-51-J made from October 3 to 7, 1985. ''Atlantis'' embarked on its 33rd and final mission, also the final mission of a space shuttle, STS-135, on July 8, 2011. STS-134 by ''Endeavour'' was expected to be the final flight before STS-135 was authorized in October 2010. STS-135 took advantage of the processing for the STS-335 Launch on Need mission that would have been necessary if STS-134's crew became stranded in orbit. ''Atlantis'' landed for the final time at the Kennedy Space Center on July 21, 2011. By th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Columbia
Space Shuttle ''Columbia'' (OV-102) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the Columbia Rediviva, first American ship to circumnavigate the upper North American Pacific coast and the Columbia (personification), female personification of the United States, ''Columbia'' was the first of five Space Shuttle orbiters to fly in space, debuting the Space Shuttle, Space Shuttle launch vehicle on STS-1, its maiden flight in April 1981. As only the second full-scale orbiter to be manufactured after the Approach and Landing Tests, Approach and Landing Test vehicle ''Space Shuttle Enterprise, Enterprise'', ''Columbia'' retained unique features indicative of its experimental design compared to later orbiters, such as test instrumentation and distinctive black Chine (aeronautics), chines. In addition to a heavier fuselage and the retention of an internal airlock throughout its lifetime, these made ''Columbia'' the heaviest of the fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hollow Cathode Effect
The hollow cathode effect allows electrical conduction at a lower voltage or with more current in a cold-cathode gas-discharge lamp when the cathode is a conductive tube open at one end than a similar lamp with a flat cathode. The hollow cathode effect was recognized by Friedrich Paschen in 1916. In a hollow cathode, the electron emitting surface is in the inside of the tube. Several processes contribute to enhanced performance of a hollow cathode: *The pendulum effect, where an electron oscillates back and forth in the tube, creating secondary electrons along the way *The photoionization effect, where photons emitted in the tube cause further ionization *Stepwise ionization *Sputtering The hollow cathode effect is utilized in the electrodes for neon signs, in hollow-cathode lamp A hollow-cathode lamp (HCL) is type of cold cathode lamp used in physics and chemistry as a spectral line source (e.g. for atomic absorption spectrometers) and as a frequency tuner for light sources ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Naval Research Laboratory
The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological development and prototyping. The laboratory's specialties include plasma physics, space physics, materials science, and tactical electronic warfare. NRL is one of the first US government scientific R&D laboratories, having opened in 1923 at the instigation of Thomas Edison, and is currently under the Office of Naval Research. As of 2016, NRL was a United States Navy Working Capital Fund, Navy Working Capital Fund activity, which means it is not a line-item in the US Federal Budget. Instead of direct funding from Congress, all costs, including overhead, were recovered through sponsor-funded research projects. NRL's research expenditures were approximately $1 billion per year. Research The Naval Research Laboratory conducts a wide v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STEX
Space Technology Experiments, or STEX, also known as NRO Launch 8 or NROL-8, was an experimental National Reconnaissance Office (NRO) satellite built by Lockheed Martin. It was launched on 3 October 1998. One of the experiments was ATEx (Advanced Tether Experiment), which was deployed on 22 January 1999, and subsequently jettisoned. ATEx The Advanced Tether Experiment (ATEx), was a follow on to the TiPS experiment, designed and built by the Naval Center for Space Technology, flown as one of the experiments on STEX. ATEx had two end masses connected by a polyethylene tether that was intended to deploy to a length of 6 km, and was intended to test a new space tether deployment scheme, new tether material, active control, and survivability. ATEx was deployed on 16 January 1999 and ended 18 minutes later after deploying only 22 m of tether. The jettison was triggered by an automatic protection system designed to save STEX if the tether began to stray from its expected depar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
