MetOp

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MetOp
MetOp model
Organization: EUMETSAT
Mission type: Meteorology/Climatology
Satellite of: Earth
MetOp-A Launch: October 19, 2006 at 16:28:00 UTC
Soyuz ST Fregat
Baikonur Cosmodrome
MetOp-B Launch: September 17, 2012 at 16:28:00 UTC
Soyuz ST Fregat
Baikonur Cosmodrome
MetOp-C Launch: Approx 2018
Soyuz ST Fregat
Guiana Space Centre
Dimensions: 6.2 × 3.4 × 3.4 metres (under the launcher fairing) 17.6 × 6.5 × 5.2 metres (deployed in orbit)
Mass: 4093 kg
Payload Mass: 812 kg
Webpage: [1]
Orbital elements
Orbit: Sun-synchronous orbit
Inclination: 98.7° to the Equator
Orbital period: 101 minutes
Ground Track Repeat Cycle: 29 Days / 412 Orbits
Mean Altitude: 817 km (eccentricity ~0)
Local Time of Ascending Node: 21:31
MetOp-A International Designator: 2006-044A
MetOp-B International Designator: 2012-049A
MetOp-C International Designator: TBA

MetOp is a series of three polar orbiting meteorological satellites operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). The satellites form the space segment component of the overall EUMETSAT Polar System (EPS), which in turn is the European half of the EUMETSAT/NOAA Initial Joint Polar System (IJPS). The satellites carry a payload comprising 11 scientific instruments and two which support Search and Rescue services. In order to provide data continuity between MetOp and NOAA Polar Operational Satellites (POES), several instruments are carried on both fleets of satellites.

MetOp-A, launched on October 19, 2006, is Europe's first polar orbiting satellite used for operational meteorology. Subsequent satellites in the series are provisionally planned for launch at 5 year intervals to match the 5-year design life and provide continuity of services. However, in case of extended mission lifetime, a period of dual operations is expected as well as an extension to the overall programme.

Background[edit]

MetOp has been developed as a joint undertaking between the European Space Agency (ESA) and European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Recognising the growing importance of Numerical Weather Prediction (NWP) in weather forecasting, MetOp was designed with a suite of instruments to provide NWP models with high resolution global atmospheric temperature and humidity structure. Data from MetOp are additionally used for atmospheric chemistry and provision of long term data sets for climate records.

MetOp Heritage[edit]

The MetOp satellites have a modular construction, comprising a Service Module, a Payload Module and a suite of Instruments.

A SPOT heritage service module provides power (via solar array and 5 batteries for eclipse), attitude and orbit control, thermal regulation and Tracking, Telemetry and Command (TT&C).

An Envisat heritage payload module provides common command and control and power buses for the instruments along with science data acquisition and transmission.

The suite of instruments are largely derived from precursors flown on The European Space Agency's European Remote-Sensing Satellite (ERS)/Envisat satellites or are fully recurrent units originally developed for NOAA's Television Infrared Observation Satellite (TIROS) series of polar-orbiting satellites.

Data Acquisition[edit]

With the exception of Search and Rescue, which is a purely local mission with its own dedicated transmitter, all data from the MetOp Instruments are formatted and multiplexed by the Payload Module and either stored on a solid state recorder for later transmission via an X-Band antenna, or directly transmitted to local users via High Rate Picture Transmission (HRPT) VHF antenna.

The main Command and Data Acquisition (CDA) head is located at Svalbard Satellite Station in Norway. The high latitude of this station allows the global data stored in the solid state recorder of each satellite to be dumped via X-Band once per orbit. Each MetOp satellite produces approximately 2 GB of raw data per orbit. Additionally, in order to improve timeliness of products, one of the operational satellites dumps the data from the descending part of the orbit over the McMurdo groundstation in Antarctica. Data are then trickle fed from the ground stations to EUMETSAT Headquarters in Darmstadt, Germany, where they are processed, stored and disseminated to various agencies and organisations with a latency of approximately 2 hours without the McMurdo ground station and 1 hour with.

HRPT is used to provide a real-time direct readout local mission via a network of receivers on ground provided by cooperating organisations. Data from these stations is also transmitted to EUMETSAT and redistributed to provide a regional service with approximately 30 minutes latency. Due to radiation sensitivity of the HRPT hardware, the MetOp-A HRPT does not operate over the polar regions or South Atlantic Anomaly.

Command and Control[edit]

Command and Control of MetOp is performed from the EPS Control Room at EUMETSAT Headquarters in Darmstadt, Germany. The control center is connected to the CDA in Svalbard which is used for S-Band ranging and doppler measurements (for orbit determination), acquisition of real-time house keeping telemetry and uplink of telecommands. The CDA at Svalbard, located at approximately 78 degrees North, provides TT&C coverage on each orbit. Commands for routine operations are generally uplinked at each CDA contact, approximately 36 hours in advance of on-board execution.

Orbit determination can also be performed using data from the GNSS Receiver for Atmospheric Sounding (GRAS) instrument.

An independent back-up control center is also located at Instituto Nacional de Técnica Aeroespacial, near Madrid, Spain.

Mission Profile[edit]

The MetOp and NOAA satellites both carry a common set of core instruments. In addition, MetOp carries a set of new European instruments, which measure atmospheric temperature and humidity with unprecedented accuracy along with profiles of atmospheric ozone and other trace gases. Wind speed and direction over the oceans will also be measured. It is expected that these new instruments will herald a significant contribution to the ever-growing need for fast and accurate global data to improve numerical weather prediction. This in turn will lead to more-reliable weather forecasts and, in the longer-term, help with monitoring changing climates more accurately.

In addition to its meteorological uses, it will provide imagery of land and ocean surfaces as well as search and rescue equipment to aid ships and aircraft in distress. A data relay system is also on board, linking up to buoys and other data collection devices.

Launch and deployment[edit]

Ground track of MetOp-B, September 2012

MetOp-A, the first ever European polar-orbiting meteorological satellite, was successfully launched on 19 October 2006 from Baikonur Cosmodrome, Kazakhstan using a Soyuz-ST Fregat launcher, after six attempts. At just over 4,000 kg and measuring 17.6 × 6.5 × 5.2 m when in orbit, MetOp is Europe's second largest Earth-observation satellite, after ENVISAT which was launched in 2002.[1]

The first signal from the satellite was received at 1835 BST on 20 October 2006, and it was confirmed that the satellite was in its nominally correct orbit with the solar panel deployed. Control of the satellite was with the European Space Operations Centre (ESOC — part of ESA) which had the responsibility of achieving the final positioning of the satellite, deployment of all the antennas and final reconfiguration of the satellite following necessary orbit control maneuvers. The satellite was handed over to EUMETSAT operations on 22 October 2006. The first image was received at 0800 UTC on 25 October[2]—a visible light image of Scandinavia and Eastern Europe — but there was a six-month period of verification and calibration of the satellite and its instrument payload before it was declared operational. Before that point, the Met Office received data and started to test and then use it as input to the operational numerical weather prediction runs.

MetOp-A was declared fully operational in mid-May 2007 and the full data of its 11 scientific instruments are available to its users on operational basis [3]

MetOp-B was declared fully operational and pronounced to replace MetOp-A as "EUMETSAT’s prime operational LEO weather satellite" in April 2013.[4]

MetOp-C was scheduled for launch towards the end of 2016,[5] which was postponed until 2017[6] and is now scheduled for 2018.[7][8]

Instruments[edit]

The following instruments[9] are flown on board the MetOp satellites:

Shared Instruments[edit]

The following instruments are shared on the NPOES satellites which form the US contribution to IJPS

  • AMSU-A1/AMSU-A2 - Advanced Microwave Sounding Units
  • HIRS/4 - High-resolution Infrared Radiation Sounder (N.B. Not included on MetOp-C)
  • AVHRR/3 - Advanced Very High Resolution Radiometer
  • A-DCS - Advanced Data Collection System
  • SEM-2 - Space Environment Monitor
  • SARP-3 - Search And Rescue Processor
  • SARR - Search And Rescue Repeater
  • MHS - Microwave Humidity Sounder

MetOp Specific Instruments[edit]

The following instruments are flown exclusively on the MetOp satellites

  • IASI - Infrared Atmospheric Sounding Interferometer
  • GRAS - Global Navigation Satellite System Receiver for Atmospheric Sounding
  • ASCAT - Advanced SCATterometer
  • GOME-2 - Global Ozone Monitoring Experiment-2

GOME-2[edit]

The first atmospheric contributions by MetOp-A were made by the Global Ozone Monitoring Experiment-2 (GOME-2), a scanning spectrometer on board the satellite. GOME-2, designed by DLR (the German Aerospace Centre) and developed by SELEX Galileo as the successor of ERS-2's GOME (1995), provided coverage of most areas of planet Earth measuring the atmospheric ozone, the distribution of surface ultraviolet radiation, and the amount of nitrogen dioxide (NO2).[10] The GOME-2 instrument provides a second source of ozone observations that supplement data from the SBUV/2 ozone instruments on the NOAA-18 and NOAA-19 satellites, which are part of the IJPS.[11]

Infrared Atmospheric Sounding Interferometer (IASI)[edit]

One of the most important instruments carried onboard MetOp is IASI, the most accurate infrared sounding interferometer currently in orbit. IASI observes the atmosphere in the infra-red (3.7 - 15.5 µm) in 8461 channels, allowing to measure the atmosphere temperature within 1°C and relative humidity within 10% for each slice of 1 km height. Earth surface is revisited twice a day. IASI by itself produces half of all MetOp data.

Plans[edit]

Subsequent MetOp satellites will be launched at approximately five-year intervals, maintaining the service until at least 2020.

The second in the series, MetOp-B, was launched on 17 September 2012[12] from the Baikonur Cosmodrome.

MetOp-A and B operate in a co-planar orbit, 174 degrees out of phase. MetOp-B High Rate Picture Transmission (HRPT) will be transmitting real time data active over all geographic zones due to upgraded hardware, while MetOp-A HRPT will continue to be switched off over high risk radiation zones.

After completion of commissioning, MetOp-B dumps recorded global data stored in the onboard solid state recorder (SSR) over McMurdo (as well as Svalbard) and MetOp-A only dumps its SSR over Svalbard.

A split-mission is being considered for the GOME-2 instruments which would involve operating them with a reduced swath to improve spatial resolution with a modest coverage penalty.

MetOp-C, the third satellite is to be launched in the 2018 timeframe, from the Guiana Space Centre.

References[edit]

  1. ^ ESA fact page
  2. ^ First Satellite Image received by Dundee University Satellite receiving station
  3. ^ Spaceflight, a publication of the British Interplanetary Society, Volume 49, Number 7, July 2007, page 245, ISSN 0038-6340.
  4. ^ EUMETSAT press release April 24, 2013
  5. ^ http://www.satellitetoday.com/publications/st/2010/09/13/eumetsat-awards-metop-c-launch-to-arianespace/
  6. ^ EUMETSAT news item, 24 April 2013
  7. ^ EUMETSAT news updates, July 2013
  8. ^ image (EUMETSAT newsletter) issue 38, July 2013
  9. ^ "CEOS EO HANDBOOK – INSTRUMENT INDEX". CEOS, the Committee on Earth Observation Satellites. 
  10. ^ Spaceflight, a publication of the British Interplanetary Society, Volume 49, Number 5, May 2007, page 166.
  11. ^ "NOAA-N Prime". NP-2008-10-056-GSFC. NASA Goddard Space Flight Center. 16 December 2008. Retrieved 8 October 2010. [dead link]
  12. ^ EUMETSAT MetOp-B Launch Event

External links[edit]