Cartosat-1 (formerly IRS-P5) is a stereoscopic

Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, me ...

in a

Sun-synchronous orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...

, and the first one of the Cartosat series of satellites. The eleventh satellite of ISRO in Indian Remote Sensing Satellite (IRS) series. The satellite was launched by

Indian Space Research Organisation The Indian Space Research Organisation (ISRO ) is India's national List of government space agencies, space agency, headquartered in Bengaluru, Karnataka. It serves as the principal research and development arm of the Department of Space (DoS), ...

and is operated by NTRO. Weighing around 1560 kg at launch, its applications will mainly be towards

cartography Cartography (; from , 'papyrus, sheet of paper, map'; and , 'write') is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can ...

in India.

Launch

It was launched by PSLV-C6, on 5 May 2005 at 04:44:00 UTC from the newly built Second Launch Pad at Sriharikota. Images from the satellite will be available from GeoEye for worldwide distribution. The satellite covers the entire globe in 1867 orbits on a 126-day cycle. Adjacent paths are covered by a separation of eleven days.

History

Department of Space (DoS),

government of India The Government of India (ISO 15919, ISO: Bhārata Sarakāra, legally the Union Government or Union of India or the Central Government) is the national authority of the Republic of India, located in South Asia, consisting of States and union t ...

, has launched a series of satellites for Earth's resource management and monitoring. These satellites have been very successful in providing data in various scales ranging from 1:1 million to 1:12,500 scale. Each of the Indian Remote Sensing satellite missions ensured data continuity while introducing improvements in the spatial, spectral and radiometric resolutions. Considering increase demand for large scale and topographic mapping data DoS launched the Cartosat-1 in 2005. Cartosat-1 is dedicated to stereo viewing for large scale mapping and terrain modelling.

Specifications

Payload

Cartosat-1 carries two state-of-the-art panchromatic (PAN) cameras that take

black and white Black-and-white (B&W or B/W) images combine black and white to produce a range of achromatic brightnesses of grey. It is also known as greyscale in technical settings. Media The history of various visual media began with black and white, ...

stereoscopic pictures of the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

in the visible region of the

electromagnetic spectrum The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...

. The swath covered by these high resolution PAN cameras is 30 km and their spatial resolution is 2.5 metres. For acquire two images simultaneously, one forward (PAN FORE) looking at +26° and one aft (PAN AFT) of the satellite at -5° for near instantaneous stereo data. The time difference between the acquisitions of the same scene by the two cameras is about 52 seconds. The spacecraft body is steerable to compensate the Earth rotation effect and to force both fore and aft cameras to look at the same ground strip when operated in stereo mode. The cameras are mounted on the satellite in such a way that near simultaneous imaging of the same area from two different angles is possible. This facilitates the generation of accurate three-dimensional maps. The cameras are steerable across the direction of the satellite's movement to facilitate the imaging of an area more frequently.

Communications

The images taken by Cartosat-1 cameras are compressed, encrypted, formatted and transmitted to the ground stations. The images are reconstructed from the data received at the ground stations. The

National Remote Sensing Centre Space programme of India Organisations based in Hyderabad, India Year of establishment missing Indian Space Research Organisation facilities ...

is responsible for acquisition, processing of data relayed by the Cartosat-1. A spherical Phased Array Antenna with steerable beam is used to transmit the data to the required ground station. A solid state recorder with 120 Gb capacity to store about 9 minutes of payload data is available for global operation of the payloads. The stored images can be transmitted when the satellite comes within the visibility zone of a ground station.

Optics and detectors

Each Panchromatic camera consists of three 3 mirror off-axis all reflective telescope with primary, secondary and tertiary mirrors. These mirrors are made from special zerodur glass blanks and are light weighted to about 60%. These mirrors are polished to an accuracy of l/80 and are coated with enhanced

aluminium oxide Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several Aluminium oxide (compounds), aluminium oxides, and specifically identified as alum ...

(AlO₂) coating. In order to meet the high resolution and the swath requirement a 12K, 7 μm linear array

charge-coupled device A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. Under the control of an external circuit, each capacitor can transfer its electric charge to a neighboring capacitor. CCD sensors are a ...

(CCD) is used as a detector.Indian Remote Sensing Satellite Cartosat-1: Technical features and data products
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Imaging capabilities

Spatial resolution

* 2.5 m panchromatic band (0.5-0.85 μm)

Temporal resolution

The revisit rate for Cartosat-1 is five days.

Radiometric resolution

The sensor collects data with a 10-bit sensitivity.

Swath

30 km (PAN-F) and 25 km (PAN-A)

References

External links

Cartosat-1 website
{{Orbital launches in 2005 Cartosat Spacecraft launched in 2005 Spacecraft launched by PSLV rockets