| 1. |
- Blomberg, Lars, et al.
(författare)
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Atrid-2 : An advanced auroral microprobe
- 1999
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Astri-2 is an advanced auroral microprobe with dual primary mission objectives; to do high-quality in situ measurements of the physical processes behind the aurora, and to demonstrate the usefulness of microspacecraft as advanced research tools. Mission success will open up entirely new possibilities to carry out low-budget multipoint measurements in near-Earth space. This long-desired kind of in situ measurements are the next major step forward in experimental space physics. Astrid-2 has platform dimensions of 45×45×30 cm, a total mass of just below 30 kg, and carries scientific instruments for measuring local electric and magnetic fields, plasma density and density fluctuations, ions and electrons, as well as photometers for remote imaging of auroral emissions. Attitude determination is provided by a high-precision star imager. Some 250 Mbytes' worth of scientific data will be received each day at the two ground stations. Astrid-2 will be launched as a piggy-back on a Russian Kosmos-3M launcher into an 83 deg inclination circular orbit at 1000 km altitude. Nodal regression will give complete coverage of all local time sectors every 3.5 months. © 1999 Elsevier B.V. All rights reserved.
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| 2. |
- Blomberg, Lars G., et al.
(författare)
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EMMA - the electric and magnetic monitor of the aurora on Astrid-2
- 2004
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 22:1, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- The Astrid-2 mission has dual primary objectives. First, it is an orbiting instrument platform for studying auroral electrodynamics. Second, it is a technology demonstration of the feasibility of using micro-satellites for innovative space plasma physics research. The EMMA instrument, which we discuss in the present paper, is designed to provide simultaneous sampling of two electric and three magnetic field components up to about 1 kHz. The spin plane components of the electric field are measured by two pairs of opposing probes extended by wire booms with a separation distance of 6.7 m. The probes have titanium nitride (TiN) surfaces. which has proved to be a material with excellent properties for providing good electrical contact between probe and plasma. The wire booms are of a new design in which the booms in the stowed position are wound around the exterior of the spacecraft body. The boom system was flown for the first time on this mission and worked flawlessly. The magnetic field is measured by a tri-axial fluxgate sensor located at the tip of a rigid. hinged boom extended along the spacecraft spin axis and facing away from the Sun. The new advanced-design fluxgate magnetometer uses digital signal processors for detection and feedback, thereby reducing the analogue circuitry to a minimum. The instrument characteristics as well as a brief review of the science accomplished and planned are presented.
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| 3. |
- Blomberg, Lars G., et al.
(författare)
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MEFISTO - An electric field instrument for BepiColombo/MMO
- 2006
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 38:4, s. 672-679
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Tidskriftsartikel (refereegranskat)abstract
- MEFISTO, together with the companion instrument WPT, are planning the first-ever in situ measurements of the electric field in the magnetosphere of planet Mercury. The instruments have been selected by JAXA for inclusion in the BepiColombo/MMO payload, as part of the Plasma Wave Investigation coordinated by Kyoto University. The magnetosphere of Mercury was discovered by Mariner 10 in 1974 and will be studied further by Messenger starting in 2011. However, neither spacecraft did or will measure the electric field. Electric fields are crucial in the dynamics of a magnetosphere and for the energy and plasma transport between different regions within the magnetosphere as well as between the magnetosphere and the surrounding regions. The MEFISTO instrument will be capable of measuring electric fields from DC to 3 MHz, and will thus also allow diagnostics of waves at all frequencies of relevance to the Hermean magnetosphere. MEFISTO is a double-probe electric field instrument. The double-probe technique has strong heritage and is well proven on missions such as Viking, Polar, and Cluster. For BepiColombo, a newly developed deployment mechanism is planned which reduces the mass by a factor of about 5 compared to conventional mechanisms for 15 in long booms. We describe the basic characteristics of the instrument and briefly discuss the new developments made to tailor the instrument to flight in Mercury orbit.
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| 4. |
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| 5. |
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| 6. |
- Marklund, Göran, et al.
(författare)
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Astrid 2, A low-budget microsatellite mission for auroral research
- 1997
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Ingår i: European Space Agency, (Special Publication) ESA SP. - 0379-6566. ; :397, s. 387-394
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Tidskriftsartikel (refereegranskat)abstract
- The next in the Astrid series of low-budget microsatellite missions will be devoted to classical auroral research. The challenge of this mission is to demonstrate the possibility to carry out comprehensive auroral investigations on a microsatellite platform having the size 0.45 × 0.45 × 0.3 m at a cost of about 2 MUSD. A successful mission will open up new less expensive ways carrying out auroral research in the future, ways which are complementary to the more ambitious programmes run within ESA and NASA. Of particular interest are multipoint measurements within the auroral acceleration region using clusters of microsatellites. New light-weight and compact instruments and deployment systems have been developed for the Astrid-2 mission. The payload will carry an integrated electric and magnetic field instrument, including a Langmuir probe, a lightweight ion and electron spectrometer, and two spin-scanning UV photometers for Lyman α and oxygen emissions in the aurora. The electric field probes will be deployed using a newly developed light-weight system for wire boom deployment. Other novel features to be used on Astrid-2 are data compression and data filtering. Astrid-2 is to be launched on a Kosmos vehicle from Plesetsk in 1997 into an 83° inclination circular orbit at 1000 km altitude. The mission will use a geographically distributed ground station network for high-speed S-band data reception, one station to be located at Solna, Sweden and another at the South African Antarctic base SANAE.
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| 7. |
- Bylander, Lars, et al.
(författare)
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A Modular Design Concept For Small Satellites
- 2002
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Ingår i: Smaller Satellites. - Dordrecht : Springer Netherlands. - 9789048159062 - 9789401730082 ; , s. 357-358
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The objectives of the new design concept (called Bylix) are to minimize the mass and power dissipation of the payload and the platform. The system design is modular to allow concurrent engineering throughout the design, integration and test phases, and to improve project management. The basis of the concept is a common “thin bus” for data and commands, power, frequency synchronization and time distribution, which requires a minimum of resources.
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| 8. |
- Bylander, Lars, et al.
(författare)
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SCALE : A Scaleable Wire Boom System
- 2002
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Ingår i: Smaller Satellites. - Dordrecht : Springer Netherlands. - 9789048159062 - 9789401730082 ; , s. 355-356
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The SCALE wire boom is a compact wire boom unit designed mainly for scientific spin-stabilized satellites. The boom unit provides storage and deployment of a wire boom (length 5–50 m) and a probe (diameter up to about 100 mm). The wire is both a boom and a supplier of the electrical connections between the probe at the end of the wire and the experiment unit in the spacecraft body. The SCALE wire boom is unique because its volume and weight are scaleable with respect to the required boom length and probe diameter.
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| 9. |
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| 10. |
- Ivchenko, Nickolay, et al.
(författare)
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Fast deployment of wire booms without residual oscillations
- 2007
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Ingår i: 18TH ESA Symposium On European Rocket And Balloon Programmes And Related Research. ; , s. 211-216
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Konferensbidrag (refereegranskat)abstract
- We present a method of fast deployment of wire booms from spinning bodies without residual oscillations. A two dimensional model of the boom-spacecraft system is developed, and analysed both theoretically and by means of numerical simulation. It is shown that for constant deployment rate, the equilibrium state during the deployment is a constant deflection angle of the boom with respect to radial direction. Oscillations about the equilibrium state are damped, so after sufficiently long deployment the boom assumes the equilibrium deflection angle. This allows to bring the boom to the radial position by introducing a period of deployment at half the rate, with its duration equal to half of the oscillation period.
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