Resurs DK
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| Organization | NTs OMZ | |
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| Mission Type | Earth observation | |
| Contractor | TsSKB Progress | |
| Satellite of | Earth | |
| Launch | June 15, 2006 on a Soyuz-FG | |
| Launch site | Baikonur Cosmodrome | |
| Mission duration | 5 years | |
| Mass | 6550 kg | |
| Payload mass | 1200 kg | |
| Max length | 7930 mm | |
| Max diameter | 2720 mm | |
| Solar panel | 36 m² | |
| Axis orientation accuracy | 0.2 arcmin | |
| Angular velocity stabilization accuracy | 0.005 degrees per second | |
| Webpage | http://eng.ntsomz.ru/spacecraft/resurs_dk | |
| Orbital elements | ||
| Inclination | 70 degrees | |
| Orbit | quasi-polar elliptical | |
| Min altitude | 360 km | |
| Max altitude | 604 km | |
| Period | 94.02 min | |
| Instruments | ||
| Visible cameras | 0.9 m panchromatic 1.5 m multispectral at 360 km altitude 0.5 m panchromatic at 222 km altitude |
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| Scientific | PAMELA and Arina | |
| Control room | ||
| Sample images | ||
US Ramstein Air Base |
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Resurs-DK1 is a commercial earth observation satellite capable of transmitting high-resolution imagery (up to 0.5 m) to the ground stations as it passes overhead. The spacecraft is operated by NTs OMZ (Research Center for Earth Operative Monitoring).
The satellite is designed for multi-spectral remote sensing of the Earth’s surface aimed at acquiring high-quality visible images in near real-time as well as on-line data delivery via radio link and providing a wide range of consumers with value-added processed data.
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[edit] Spacecraft
The Resurs-DK1 spacecraft was built by the Russian space company TsSKB Progress in Samara, Russia. It is modified version of military reconnaissance satellite Yantar-4KS1 (Terilen)[1]. The spacecraft is three-axis stabilized. The design lifetime is no less than 3 years, 5 years is expected. Ground location accuracy is 100 m. Onboard storage is 768 G-bits. Data link speed to the ground station is 300 Mbit/s. Maximum daily productivity is 1 million square km.
"DK" in the name stands for Dmitry Kozlov, chief designer of the first satellite of this class Yantar-2K.
[edit] Optical subsystem
- Type: apochromatic telephoto
- Focal length: 4000 mm
- Objective diameter: 500 mm
- Spectral range: 0.5-0.9 µm
- Mass: 310 kg
Made by Vavilov State Optical Institute, Russia. [2]
[edit] Spectral Resolution
- 0.58-0.8 µm panchromatic
- 0.5-0.6 µm green
- 0.6-0.7 µm red
- 0.7-0.8 µm visible near IR (near infrared)
Green, red and near IR are typically combined to make a traditional false color composite where the near IR is displayed in red, the red is displayed in green, and the green is displayed in blue. This combination is favoured by scientists because near IR is useful for detection of numerous vegetation types. Vegetation appear as redtones, the brighter the red, the healthier the vegetation. Soils with no or sparse vegetation range from white (sand, salt) to greens or browns depending on moisture and organic matter content. Water appears blue, clear water is dark blue to black while shallow waters or waters with high sediment concentrations are lighter blue. Urban areas will appear blue towards gray. Clouds and snow are white.
It is not possible to represent an image in true color because there is no blue band (0.4 - 0.5 µm). However, it is possible to combine red, green and near IR in such way that the appearance of the displayed image resembles a visible colour photograph, i.e. vegetation in green, water in blue, soil in brown. This is not always possible because two similarly coloured objects can have completely different reactions to near IR light.
[edit] Focal Plane Unit
Unit features 4 TDI (Time Delay and Integration) sensor arrays, one panchromatic and three multispectral. Each sensor array is composed of 36 "Kruiz" CCD chips. Effective length of the single array is about 36000 pixels. Arrays are grouped in 3 separated lines:
- near IR
- panchromatic and red
- green
This separation is causing a time delay of the colour images combined from green, red and near IR, so fast moving objects are shown in triplets. Moving object speed and direction can be calculated. All 4 arrays can work simultaneously, so it is possible to combine panchromatic and 3 multispectral images in one pansharpened color composite.
Sistem use 10-bit ADC
Focal Plane Unit is made by NPO Opteks, Russia [3]
[edit] CCD
The CCD "Kruiz" is a 1024 pixel x 128 line, high speed TDI sensor. The active imaging area is organized as 1024 vertical columns and 128 horizontal TDI rows. [4]
- Pixel size: 9 x 9 µm
- Number of TDI stages electronically selectable: 128, 64, 32, 16, 8
- Two readout shift registers and two output amplifiers allowing twice faster readout
- Selftest without illumination
- Full well capacity: 120 000 electrons
- Dynamic range: 2500
- Charge transfer efficiency in any direction: more than 0.99998 per transfer
- Maximum quantum efficiency: 0.33 (at 0.72 µm).
Designed jointly by NPO Opteks and CNII Electron.
Produced by CNII Electron [5]
[edit] Spatial resolution
[edit] Panchromatic
At the altitude of 222 km
- Nadir: 0.5 m
At the altitude of 360 km
- Nadir: 0.9 m
- 30 degrees tilt: 1.0 m
At the altitude of 604 km
- Nadir: 1.5 m
- 30 degrees tilt: 1.7 m
[edit] Multispectral
1.5-2 m [6]
[edit] Note
Image resolution can be improved by lowering spacecraft altitude, but it can be lowered only to the certain level below all objects are coming out of focus. This limit is imposed by hyperfocal distance of satellite optics. In example for IKONOS that altitude is 583 km, for QuickBird is 439 km. Due to its military heritage the hyperfocal distance of Resurs-DK optics is only 222 km assuming that circle of confusion is the same as CCD pixel size 9 µm. At this altitude panchromatic resolution of Resurs-DK imagery is 0.5 m.
Indeed, typical orbit for old Soviet reconnaissance satellite Yantar-4KS1 (Terilen) is about 225 km. [7]
However due to atmospheric drag at 222 km, the spacecraft would constantly lose orbital energy so it would require reboost to a higher orbit from time to time. This stationkeeping manoeuvres combined with orbit manoeuvres intended to shorten revisit time would dramatically increase fuel consuption and shorten mission duration to 1-1.5 year. In order to increase mission life the higher 360 x 604 km orbit is selected.
Inevitably, when fuel runs out, Resurs-DK will drift to 222 km orbit and at its bitter end will produce the best images.
[edit] Temporal resolution
The revisit rate is 5 to 7 days off-nadir.
[edit] Swath
Swath width at the altitude of 350 km:
- 4.7 - 28.3 km (at nadir)
- 40 km (at ±30°)
[edit] Arina
Russian research hardware for detection of high-energetic electrons and protons, their identification, detection of high-energetic particles bursts – earth-quake signs.
- Mass: 9 kg
[edit] PAMELA
PAMELA Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics is Italian research hardware, meant for exploration of antiparticles of nuclear and electron-positron composition of primary cosmic rays.
- Mass: 470 kg
[edit] Major Current Tasks
- Data supply for resource management and economical activity (inventory of natural resources, topographic and thematic mapping).
- Monitoring of pollution sources of the atmosphere, water and soil with the view of providing Federal and regional environmental authorities with the relevant information to make management decisions.
- On-line monitoring of man-caused and natural emergencies for the purpose of effective planning and timely performing of measures to eliminate damages.
- Supplying home and foreign consumers on a commercial basis.
- Research activities (PAMELA and Arina experiments).
