Meteor-3M-1

The Meteor-3M spacecraft series represents a modernization of Russia's national meteorological satellite system sponsored by Roskosmos, Moscow. The overall objective are environmental monitoring in the following fields:

• Monitoring of ocean and land surfaces

• Meteorological observations: Distribution of cloud data and vertical ozone profiles, monitoring of global atmospheric parameters such as temperature and water vapor profiles and to obtain sea surface wind profiles and SST

• Measurement of vertical profiles of aerosol, ozone and other constituents in the atmosphere (SAGE-III)

• Measurement space environment parameters (space weather) such as: particle fluxes and radiation density fluxes.

The US instrument SAGE-III is flown on the Meteor-3M-1 mission (joint mission of Rosaviakosmos and NASA). A corresponding cooperative agreement was approved by the Gore-Chernomyrdin Commission on Dec. 16. 1994. Plans for Meteor-3M are to combine the meteorological observations of the Meteor-3 series with the Earth-surface observations of the Resurs series, starting with Meteor-3M-2 (also referred to as Meteor-3M-1) with a planned launch in 2007 (operational capability for meteorology applications). ^{1) 2) 3) 4)}

Figure 1: Functional layout of the Meteor-3M satellite series

Spacecraft:

The Meteor-3M-1 spacecraft was designed and built by NIIEM (Scientific Research Institute for Electromechanics) in Istra, Russia. The spacecraft structure consists of: a) hermetic container with instrument rack, b) instrument platform, and c) solar arrays. Most electronics and some service system modules are contained in the hermetic container. Most payload instruments and some service modules are mounted to the external thermally stabilized platform. Significant changes have been introduced including the modification of attitude system, installation of new radio transmission system and modification of the information devices and measurement instruments.

The spacecraft is three-axis stabilized. The S/C pointing accuracy 0.1º, the angular drift rate is 0.0005º/s. A navigation subsystem (GPS/GLONASS receiver) provides orbit determination and timing services. Solar power of 2 kW (BOL) is provided by two deployed panels which are continuously sun pointed for optimum power generation (solar panel area of 23 m², solar array span of 14 m). The S/C mass is about 2500 kg (payload mass of ~900 kg), the design life is three years.

Figure 2: Illustration of the Meteor-3M spacecraft (image credit: Roskosmos)

Launch: A launch of Meteor-3M-1 took place on Dec. 10, 2001 on a Zenit-2 launch vehicle from the Baikonur Cosmodrome, Kazakhstan (launch provider: NPO Yuzhnoye).

Secondary payloads on the flight are the Badr-B satellite of Pakistan, Maroc-Tubsat of Morocco, the Compass spacecraft of IZMIRAN, Moscow, and REFLECTOR (Retroreflector Ensemble For Laser Experiments Calibration Testing & Optical Research), a US/Russian nanosatellite, funded by AFRL and developed by ISDE (Institute of Space Device Engineering), Moscow. The objective of the passive REFLECTOR spacecraft is to support SLR (Satellite Laser Ranging) experiments. ⁵⁾

Orbit: Sun-synchronous near-circular polar orbit, altitude = 1012 km, eccentricity = 0.0024, inclination = 99.63º, local time of ascending node is 9:15 AM, period = 105.33 min, path offset/revolution = 26.334º, revisit time = 3 days (41 revolutions).

RF communications: An onboard information system (OBIS) is being used for recording of instrument data streams up to 150 kbit/s from a single instrument. The solid-state recorder has a capacity of 100 Gbit. OBIS provides time compression of collected data streams with the following output options (RF data downlinks). OBIS has a mass of 20 kg and a power consumption of 32 W.

• S-band (N1 digital data streams, 1.67-1.71 GHz broadcast to HRPT-compatible stations at a data rate of 665.4 kbit/s, NOAA-POES series compatible)

• S-band (N2 digital data stream, 1.67-1.71 GHz broadcast to a ground network of AIRS (Autonomous Information Reception Station) at a data rate of 66.54 kbit/s)

• VHF-band (analog data stream, 137.3-137.85 MHz broadcast compatible with APT standard)

• X-band (8.320, 8.064 or 8.192 GHz, digital recorder dump rate of 61.44 Mbit/s and 15.36 Mbit/s to ground stations).

The S/C monitoring and control functions (TT&C) are being performed by the Roskosmos Mission Control Center in Korolev (Moscow Region), Russia. The payload data are being received, processed and archived by NPO Planeta, the main center of Roshydromet. The SAGE-III data capture and processing is being performed at NASA/LaRC via a WFF (Wallops Flight Facility) ground station.

Figure 3: Line drawing of the Meteor-3M spacecraft (image credit: NASA)

Mission status:

The Meteor-3M spacecraft stopped functioning on March 6, 2006 due to a breakdown of its power supply system resulting in a loss of communications with the spacecraft. - With a launch on Dec. 10, 2001, the spacecraft (with a design life of 3 years) provided over 4 years of successful operations.

Sensor complement:

The Meteor-3M-1 sensor complement consists of the following instruments: MR-2000-M1; KLIMAT; MIVZA; MTVZA; MSU-E; SAGE-III; SFM-2; KGI-4C, and MSGI-5EI. ^{6) 7) 8)}

[Note: The Meteor-3M-2 sensor complement consists of the following instruments: MTVZA, MSU-MR (2 instruments), MSU-SR (2 instruments), IKFS-2, MSGI-MKA, KGS-4S, a DCS (Data Collection System), RRA (RetroReflector Array), and SAGE-III of NASA/LaRC.]

Table 1: Overview of the instrument complement on Meteor-3M-1

MR-2000M1 (TV Camera System-2000-M1):

Objective: Observation of daytime Earth cloud cover in the visible spectrum (0.5 - 0.8 µm) at a local solar angle not less than 5^º. Spatial resolution of 0.7-1.4 km. The instrument has been flown on the following missions: Meteor-3-1 (1985), Meteor-3-3, Meteor-3-4, Meteor-3-5, Meteor-3-6, and Meteor-3-7. The MR-2000M1 camera provides storage and direct transmission operation.

Klimat (Infrared Radiometer):

The instrument was originally flown on the Meteor-3 series, operational since 1988 (Meteor-3-3 to Meteor-3-7). Klimat is an electromechanical device with a scan angle of ± 48º, providing a total swath width of 3100 km. IFOV=0.7 x 1.4 mrad; surface temperature range = 223-313 K; temperature difference at 300 K, background = 0.2 K. Measurement spectrum: 10.5 to 12.5 µm. Instrument mass = 75 kg. Detectors: CdHgTe cooled to 80 K. Output products: Global photomosaics of northern and southern hemispheres, tropical zone, individual images; digital SST and top-of-cloud height charts, tropical cyclone coordinates, cloud amount data on regular grid over the globe.

MIVZA (Microwave Humidity Sounder) of Roshydromet:

The objective is to provide an estimate on the total humidity of the atmosphere (water vapor). MIVZA is a 5-channel scanning radiometer within the 20-90 GHz range.

MSU-E (High-Resolution Multispectral Pushbroom Imager):

The instrument provides three spectral bands (0.5 - 0.6 µm, 0.6 - 0.7 µm, 0.8 - 0.9 µm), the spatial resolution is 38 m with a swath width of 76 km. The instrument features a cross-track pointing capability thus providing a FOR (Field of Regard) of 430 km. Data quantization of 8 bit. - MSU-E was also flown on the Resurs-O1 series (1985-2000) and on the PRIRODA module of the MIR Station.

From a historical point of view: Spaceborne CCD pushbroom detector technology was globally introduced with MSU-E, first flown on the Meteor-Priroda-5 (launch June 18, 1980) spacecraft of the former Soviet Union. ⁹⁾ MSU-E was built at ISDE (Russian Institute of Space Device Engineering) in Moscow; it featured a CCD line array of 1024 pixels, three parallel line arrays, each of 1024 elements, and provided pushbroom imagery in three spectral bands (visible range). MSU-E provided a nadir view with a FOV of 2.5º. A radiation cooler provided a detector temperature in the range of -30 to -50ºC. Instrument mass of 17 kg. No in-flight calibration was performed.

MTVZA (Microwave Imaging/Sounding Radiometer):

MTVZA was designed and developed at the Space Observations Center, Moscow, under contract to Roskosmos. MTVZA is a passive 26-channel microwave radiometer (similar to NOAA's AMSU-A and -B radiometers).

The objective of the MTVZA instrument is to monitor ocean and land surfaces as well as global atmospheric parameters such as temperature and water vapor profiles and to obtain sea surface wind profiles. MTVZA is a conical scanning instrument with a common field of view for imaging and sounding channels (simultaneous multispectral and polarization measurements), due to the single antenna design. The operating frequencies are located in the transparent atmospheric windows at 19, 33, 36.5, 42, 48, and 91.65 GHz, as well as in the oxygen absorption lines at 52-57 GHz and water vapor at 22.235 and 183.31 GHz. In addition, MTVZA includes some complementary (non-typical) frequencies used for oceanographic research. ^{10) 11) 12)}

Observation geometry: MTVZA is a conical-scanning radiometer rotating continuously about an axis parallel to the local spacecraft vertical with a period of 2.5 s during which the subsatellite point, moving at 6.32 km/s, travels 15.8 km. The view direction of the instrument is backwards (anti-velocity direction) with a viewing angle of 53.5º and an incidence angle of 69º (with respect the the surface). The sampling resolution is 17.8 km x 15.8 km in the cross-track and along-track direction respectively for channels of 91.6 GHz (Table 4). The scan direction is from the left to the right when looking in the aft direction of the spacecraft, with the active scene measurements in the range from -60º to +27º about the aft direction, resulting in a swath width of 2200 km.

Table 2: Geophysical parameters derived from MTVZA

Table 3: Channel characteristics of MTVZA

Note: Channels 22-26 are only available in the next version of the MTVZA instrument to be flown on Meteor-3M-2

All instrument channels are switched to single feed-horn antenna. MTVZA employs a total-power radiometer design providing a better sensitivity (factor 2) over a conventional Dicke-switched system. The channels in the 19-48 GHz domain are direct amplification radiometers, while the channels in the 52-57, 91 and 183 GHz range are realized as as superheterodyne receivers using balanced mixers. The performance parameters are given in Tables 3 and 4.

The antenna system of MTVZA consists of an offset parabolic reflector of dimensions 50 cm x 65 cm, illuminated by a broadband, eleven-port feed-horn antenna through the flat mirror. The configuration of the two mirror antenna system is due to the instrument deployment mechanism in the down part of spacecraft. The flat mirror and feed-horn antenna are mounted on a drum for the purpose to provide an invariant viewing and polarization geometry for the reflector scan. The drum contains the various system components like radiometers, digital data subsystem, power and the signal transfer assembly, which rotates continuously about an axis parallel to the local spacecraft vertical. The power, commands, all data, timing and telemetry signals pass through slip ring connectors to the rotating assembly.

Hot and cold reference absorbers are used for calibration. They are mounted on the non-rotating part of instrument and are positioned such that they pass between the feed-horn and the flat mirror, occulting the feed-horn once each scan. The temperature difference between hot and cold target is 50-60 K. The S/C test results for the hot and cold targets are in a good agreement with those obtained during ground thermal/vacuum testing.

Figure 4: Illustration of the MTVZA instrument ¹³⁾

Table 4: Performance characteristics of MTVZA

Geophysical Monitoring System Complex :

The Geophysical Monitoring System Complex consists of two instruments: 1) MSGI-MKA (Spectrometer for Geoactive Measurements), and 2) KGI-4C (Radiation Monitoring System). - The MSGI-MKA instrument, also referred to as MSGI-5EI, features four channels for the measurement of the following parameters: ¹⁴⁾

• Electron fluxes in the energy range of 0.1-15 keV (high-sensitivity channel)

• Ion (proton) fluxes in the energy range of 0.1-15 keV (high-sensitivity channel)

• Electron fluxes in the energy range of 0.1-15 keV (low-sensitivity channel)

• Monitoring of integral electron fluxes with a threshold energy of 40 keV

The FOV (Field of View) is 10º x 10º for each channel (3) and 20º x 20º for the integral electron flux. The instrument has a mass of 5 kg and a power consumption of 6.8 W.

KGI-4C (Radiation Monitoring System):

The objective is to monitor flux densities within the following threshold energy ranges:

• Total proton flux threshold energy of: 5, 15, 25, 30, and 40 MeV

• Total electron flux threshold energy of: 0.17, 0.7, 1.7, 2.0 and 3.2 MeV

• Proton fluxes with threshold energies of: 25 and 90 MeV

The KGI-4C instrument has a mass of 12 kg and a power consumption of 6.8 W (max).

RRA (RetroReflector Array):

RRA is also referred to as SRR (Spherical RetroReflector), an experimental device developed by IPIE (Institute for Precision Instrument Engineering) of Moscow. The RRA is a glass ball 60 mm in diameter, fastened in a holder providing observation from Earth at elevations more than 30º (the retroreflector field of view is centered in the nadir direction). The spherical retroreflector with its holder is fixed to the METEOR-3M spacecraft. The expected return signal strength level is between LAGEOS and ETALON. A secondary mission objective is the flight testing of RRA for precise laser ranging. SLR tracking is being used for precise orbit determination and retroreflector research. SLR mission support began on 1 May 2002. ^{15) 16) 17)}

The new type of the experimental spherical retroreflector is a ball lens made of several (at least two) layers of glass having different refraction index values.

Figure 5: Illustration of the spherical retroreflector in holder (image credit: IPIE)

SFM-2 (Spectrophotometer-2):

The objective is to provide an estimate of the vertical ozone distribution. Measurements are obtained using the absorption method in 4 channels in frequency band 0.25-0.6 µm. This permits the derivation of the ozone profile from approximately 5 km up to 80 km in altitude.

SAGE III (Stratospheric Aerosol and Gas Experiment III):

SAGE-III PI: M. P. McCormick, Hampton University, Hampton, VA (formerly NASA/LaRC). The instrument was built at Ball Aerospace of Boulder, CO, as prime contractor. SAGE-III was selected to fly on Meteor-3M and on ISS (International Space Station) in 2005. SAGE III is an Earth limb-scanning grating spectrometer to measure vertical profiles of aerosol, ozone and other constituents in the atmosphere. The SAGE-III instrument is part of the NASA EOS mission in characterizing the Earth system. ^{18) 19) 20) 21)}

Figure 6: Illustration of the SAGE-III instrument (image credit: NASA/LaRC)

Background and heritage: SAM [SAM (Stratospheric Aerosol Measurement) was flown on ASTP (Apollo-Soyuz Test Project), July 15-24, 1975, to perform the first successful solar occultation measurement of stratospheric aerosol], SAM II (launch Oct. 24, 1978 on Nimbus-7), SAGE I, SAGE II). Both SAM and SAM-II were single spectral instruments measuring the aerosol extinction near the 1000 nm wavelength region. Multiple spectral measurements began with SAGE-I, with a launch on the AEM-2 (Application Explorer Mission-2) satellite, Feb. 18, 1979. SAGE-II is an advanced version of SAGE-I with 7 channels at 385, 448, 453, 525, 600, 940, and at 1020 nm. SAGE-II was flown on ERBS with a launch on Oct. 5, 1984 (as of 2004 SAGE-II is still operational on ERBS). The measurements of SAM-II, SAGE-I and SAGE-II have provided long-term observations of aerosol and ozone for over 20 years. ²²⁾

Figure 7: Cutaway illustration of the SAGE-III instrument (image credit: NASA/LaRC)

Figure 8: Photo of the SAGE-III instrument (image credit: NASA/LaRC)

The SAGE-III instrument has the following science objectives: ^{23) 24) 25) 26) 27)}

• Retrieve global profiles (with 1 to 2 km vertical resolution) of atmospheric aerosols, ozone, water vapor, NO₂, NO₃, OClO, temperature and pressure in the mesosphere, stratosphere and troposphere

• Investigate the spatial and temporal variability of the measured species in order to determine their role in climatological processes, biogeochemical cycles, the hydrologic cycle, and atmospheric chemistry

• Characterize tropospheric and stratospheric aerosols and upper tropospheric and stratospheric clouds, and investigate their effects on the Earth's environment, including radiative, microphysical, and chemical interactions

• Extend the SAM II, SAGE I and SAGE II self-calibrating solar occultation data sets (begun in 1978), enabling the detection of long-term trends

• Provide atmospheric data essential for the calibration and interpretation/correction of other satellite sensors, including EOS- and ground-based sensors.

Measurement approach: The self-calibrating solar and lunar occultation technique is employed, with nine spectral channels, from 280 to 1550 nm, to study aerosols, ozone, OClO, NO₂, NO₃, water vapor, temperature, and pressure. The instrument looks at the sun (or the moon) through the Earth's limb, utilizing a two-axis passive suntracker with a scan mirror,that scans the FOV across the solar disk (obtaining multiple samples at each altitude).

• For solar occultation measurements, the operation of the SAGE-III instrument in orbit is similar to the operation of the previous SAGE instruments. Before a solar occultation event, the telescope and scan head is first slewed to the azimuth position where the sun will appear. As soon as the sun appears in the instrument's FOV, the scan mirror begins to scan in elevation to acquire the solar image. The 0.5 arcmin science aperture in the vertical direction provides approximately a 0.5 km vertical resolution in the atmosphere. Measurements are obtained by repeatedly scanning up and down over the solar disk at the Earth's limb over a height region from the ground to about 300 km altitude as the sun rises or sets from the satellite perspective.

• The capability of lunar measurements arises from the use of the CCD detector, which can provide high sensitivity with variable signal integration time. Since SAGE III is capable of measuring the moon's brightness (about 600,000 times less bright than the sun), it possesses the ability to make measurements of limb scattering on the bright side of each orbit. - Lunar occultation measurements are being performed by the SAGE-III instrument when the brightness of the moon is 40 % or greater of a full moon. Lunar measurements are sampled at 10 samples/s due to the needed long integration time for the weaker signal. The spectral coverage for the lunar measurement can, therefore, be increased to 340 spectral channels over the CCD. The limb scattering measurements are considered to be a research mode for SAGE-III and are just now beginning to be conducted. Early limb scattering results are of high quality and showing success, especially for ozone profile measurements. ^{28) 29)}

Table 5: Some SAGE-III instrument parameters

SAGE-III consists of three major subsystems:

1) Pointing subsystem: It consists of a scan mirror which acquires the radiant target and performs vertical scanning across the target. The scan mirror is mounted on an azimuth drive which rotates over 360º for pointing in azimuth direction.

2) Imaging subsystem. The objective is to produce a focused image of the target at a focal plane where the instrument's field of view is situated. - A Dall-Kirkham telescope design is used with an f/4 ratio. A slit (1/2 x 5 arcmin), located in the focal plane, serves as aperture and as entrance slit to the grating spectrometer. The entire telescope assembly, including scan mirror, can rotate in azimuth to eliminate the problem of image rotation during azimuth rotation. The target sensor assembly is mounted on the back of the telescope secondary and on the side of the telescope housing. The target sensor consists of a bi-level photodiode, capable to perform both solar and lunar acquisition with a change in dynamic range of six orders of magnitude.

3) Spectrometer subsystem. The objective is to measure solar radiation from 280 to 1040 nm and 1 to 2 nm spectral resolution. An additional photodetector measures radiation at 1550 nm. The spectrometer is a new design, utilizing a holographic, aberration-reduced grating to provide stigmatic imaging at 440 and 868 nm with 1 nm resolution below 450 nm and 2 nm resolution between 740 and 960 nm. The detector array consists of two elements, a Tektronix 800x10 pixel backside-illuminated CCD array (283-1030 nm range) and an infrared photodiode (InGaAs type for measurements at 1550 ±15 nm) that are spatially co-registered.

The spectrometer with the CCD array assembly provides continuous wavelength coverage between 290 and 1040 nm with a spectral resolution between 1.2 to 2.5 nm, permitting the measurement of multiple absorption features of each gaseous species and multi-wavelength measurement of broadband extinction by aerosols. Nine channels are routinely utilized in solar occultation measurements and three channels are used in lunar measurements. - Spectral calibration is continuous, combined with the self-calibrating nature of the occultation technique. In addition, the CCD array permits in-orbit wavelength and intensity calibration from observations of the exo-atmospheric solar Fraunhofer spectrum.

Table 6: SAGE III channel specifications

Table 7: SAGE III measurement capability (single profile)

Table 8: Overview of some SAGE-III products

The SAGE-III retrieval algorithm is a procedure converting the instrument's response to solar or lunar flux (about 70-80 spectral bands) into vertical profiles of molecular density of gaseous species, aerosol extinction at eight wavelengths, temperature, and pressure.

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The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.