Swarm (spacecraft)

Swarm

Artist's view of the three Swarm spacecraft
Mission type Earth's magnetic field observation
Operator ESA
COSPAR ID SWARM A: 2013-067B
SWARM B: 2013-067A
SWARM C: 2013-067C
SATCAT no. SWARM A: 39452
SWARM B: 39451
SWARM C: 39453
Website eoPortal - SWARM
Mission duration 4 years (planned)
Elapsed: 3 years, 9 months, 3 days
Spacecraft properties
Manufacturer Astrium
Launch mass 468 kilograms (1,032 lb)
Dry mass 369 kilograms (814 lb)
Dimensions 9.1 m × 1.5 m × 0.85 m
Power 608 watts
Start of mission
Launch date 22 November 2013,
12:02:29 UTC
Rocket Rokot/Briz-KM
Launch site Plesetsk Site 133/3
Contractor Eurockot
Orbital parameters
Reference system Geocentric
Regime Polar orbit
Perigee SWARM A: ≤460 km (290 mi)
SWARM C: ≤460 km (290 mi)
SWARM B: ≤530 km (330 mi)
Apogee SWARM A: ≤460 km (290 mi)
SWARM C: ≤460 km (290 mi)
SWARM B: ≤530 km (330 mi)
Inclination SWARM A: 87.4°
SWARM C: 87.4°
SWARM B: 88°
Mean motion 15
Epoch Planned
Transponders
Band S Band
Frequency 2 GHz
Bandwidth 6Mbit/s download
4kbit/s upload
Instruments
VFM: Vector Field Magnetometer
ASM: Absolute Scalar Magnetometer
EFI: Electric Field Instrument
ACC: Accelerometer
LRR: Laser Range Reflector

Swarm is a European Space Agency (ESA) mission to study the Earth's magnetic field. High-precision and high-resolution measurements of the strength, direction and variations of the Earth's magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide data for modelling the geomagnetic field and its interaction with other physical aspects of the Earth system. The results offer a view of the inside of the Earth from space, enabling the composition and processes of the interior to be studied in detail and increase our knowledge of atmospheric processes and ocean circulation patterns that affect climate and weather.

Overview

The overall objective of the Swarm mission is to build on the experience from the Ørsted and CHAMP missions and to provide the best ever survey of the geomagnetic field (multi-point measurements) and its temporal evolution, to gain new insights into the Earth system by improving our understanding of the Earth's interior and climate.[1]

The Swarm constellation consists of three satellites (Alpha, Bravo & Charlie) placed in two different polar orbits, two flying side by side at an altitude of 450 km (280 mi) and a third at an altitude of 530 km (330 mi).[1][2] The launch was delayed and rescheduled to 12:02:29 UTC (7:02:29 a.m. EST) on 22 November 2013, from Plesetsk Cosmodrome, Russia.[3] ESA contracted Astrium to develop and build the three orbiters,[1] while Eurockot provided the launch services.[4]

Scientific objectives

Primary objectives:

Secondary objectives:

Payload

The payload of the three spacecraft consists of the following instruments:[2]

Mission History

Pre-launch

The three SWARM satellites arrived at the Plesetsk Cosmodrome in September 2013 to begin final testing before fuelling and incorporation with the Rokot launch vehicle.[5]

Launch

The SWARM constellation was successfully launched aboard Rokot/Briz-KM on November 22, 2013.[6]

Operations

The constellation is controlled by the European Space Operations Centre in Darmstadt, Germany. By the beginning of May 2014 SWARM had finished its in orbit commissioning.[7] Preliminary data indicates that the constellation is performing well as data received closely matches that from a previous German mission, CHAMP.[7]

During the commissioning stage problems were discovered with the backup Magnetometer on the 'Charlie' satellite, this led to 'Bravo' satellite being placed in the lone high altitude orbit (510km) with 'Charlie' joining 'Alpha' in the lower tandem orbit (462km) to improve the resilience of the constellation.[7] Commissioning data also indicated greater noise in data when a satellite was in view of the sun, the current theory is this is caused due to differential heating in the satellite but this has not been confirmed.[7] Overall the constellation is in good health and due to accurate orbital insertion has significant fuel reserves remaining.[7]

Discoveries and applications

In September 2016 scientists published a study that revealed a direct link between GPS blackouts of low-earth orbiting satellites and 'thunderstorms' in the ionosphere. During the first two years of Swarm's operation their GPS connection was broken 166 times.[8] The high-resolution observations from the satellite helped to link these outages to ionospheric thunderstorms 300-600km in the Earth's atmosphere.[9]

In December 2016 scientists announced that, by using data from the Swarm satellites, they had discovered a new feature in the Earth's outer core. A jet-stream of rapidly moving liquid iron moving at around 50 km per year.[10][11]

In April 2017, Swarm's data was used to confirm that Steve was a previously unrecognized atmospheric phenomenon.[12]

See also

References

  1. 1 2 3 ESA. "SWARM". eoPortal. Retrieved 2013-08-21.
  2. 1 2 SWARM Technical Annex, 2004
  3. ↑ "Satellites packed like sardines". ESA. 8 November 2013. Retrieved 11 November 2013.
  4. ↑ Eurockot to launch two ESA Earth observation missions, 9 April 2010
  5. ↑ "Preparing to Launch SWARM". ESA. 19 September 2013. Retrieved 19 September 2013.
  6. ↑ "Esa's satellite Swarm launch to map Earth's magnetism". BBC News. 22 November 2013.
  7. 1 2 3 4 5 "Swarm 'delivers on magnetic promise'". BBC. 2 May 2014. Retrieved 2 May 2014.
  8. ↑ "Swarm reveals why satellites lose track". ESA. 28 October 2016. Retrieved 27 January 2017.
  9. ↑ "Strange blackouts hits Space satellites near Equator". DTU Space. 30 September 2016. Retrieved 27 January 2017.
  10. ↑ Amos, Jonathan (19 December 2016). "Iron 'jet stream' detected in Earth's outer core". BBC. Retrieved 8 January 2017.
  11. ↑ Livermore, Philip W.; Hollerbach, Rainer; Finlay, Christopher C. (19 December 2016). "An accelerating high-latitude jet in Earth’s core". Nature. 10: 62–68. doi:10.1038/ngeo2859.
  12. ↑ McRae, Mike (24 April 2017). "Introducing Steve - a Newly Discovered Astronomical Phenomenon". ScienceAlert.
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