Satellite Technology

Sentinel-1B. Image: ESA–Manuel Pedoussaut.
Landsat 8. Image: NASA.
Swarm Earth Explorer constellation. Image: ESA-P. Carril.

Among the services that satellites can provide for disaster risk management and emergency response are weather forecasting, remote sensing, geo-positioning, navigation, television and telecommunication. Instruments onboard satellites circling the Earth are designed to cover specific wavelength ranges of the electromagnetic spectrum in order to capture images, atmospheric sounding, satellite communication, geo-positioning and navigation.

Satellites are circling Earth in different orbits depending on the type of application or instrument onboard: A satellite in a geostationary orbit circles the Earth above the equator (0° latitude) synchronously to the Earth's rotation. Its apparently fixed position above a point on the equator at an altitude of more than 36,000 km makes it suitable for communications and regional climate observation of that specific area, with high temporal but low spatial resolution.

Earth observation satellites and satellites for meteorological purposes are located in low Earth orbit at an altitude of typically about 500-800 km and near polar inclination. Due to their orbit, these satellites provide global coverage with comparatively lower temporal, but medium to very high spatial resolution. Due to the high costs of space transportation, constellations of communication or navigation satellites are also placed in Low Earth Orbit.

Earth Observation satellites use either optical or radar sensors to capture images of Earth: Optical sensors for Earth observation are designed to deliver images in either panchromatic spectral format or multispectral format. Panchromatic refers to images in black and white that are reflected from Earth's surface exposed to all visible light. Multispectral images usually include four bands of the electromagnetic spectrum: blue, green, red and near-infrared.

Radar sensors for Earth observation are designed to operate in the microwave range.

Overview on satellite missions and instruments

Amazônia-1
Hazard types:
Drought, Forest Fire, Geophysical, Hydrological
Applications:
Amazônia-1 image data will be used to monitor deforestation, particularly over the Amazon region in Brazil. Other applications will include monitoring of agricultural dynamics, coastal regions, water reservoirs, natural disasters, and more.
Launch Date:
Feb 2021
Operator:
INPE
Aqua
Hazard types:
Harmful Algal Bloom, Drought, Tsunami, Flood, Severe Storm, Extreme Temperature
Applications:
Collecting information about the Earth’s water cycle including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice. Additional variables being measured include radiative energy fluxes, aerosols, vegetation cover on the land, phytoplankton and dissolved organic matter in the oceans, and air, land, and water temperatures.
Launch Date:
May 2002
Operator:
NASA
AURA
Hazard types:
Applications:
Atmospheric chemistry, ozone and air quality
Launch Date:
Jul 2004
Operator:
NASA
Beijing-1
Hazard types:
Applications:
Launch Date:
Oct 2005
Operator:
NRSCC
BGUSAT
Hazard types:
Climatological
Applications:
Through the BGUSAT cameras, researchers will be able to track atmospheric gases like CO2 in order to understand climate change, to examine changes in ground moisture that could be an indicator of desertification and affect agricultural development or to monitor plant development in different regions.
Launch Date:
Feb 2017
Operator:
Ben-Gurion University of the Negev
BlackSky Global
Hazard types:
Applications:
Very high resolution optical data (for multi-daily revisit)
Launch Date:
Nov 2018
Operator:
BlackSky
CALIPSO
Hazard types:
Applications:
Measurements of aerosol & cloud properties for climate predictions, using a 3 channel lidar and passive instruments for coincident observations of radioactive fluxes and atmospheric state
Launch Date:
Apr 2006
Operator:
NASA, CNES
Capella
Hazard types:
Forest Fire, Subsidence, Landslide, Flood
Applications:
High resolution and timely SAR-X
Launch Date:
Dec 2018
Operator:
Capella
Cartosat-1 / IRS-P5
Hazard types:
Drought, Glacial Lake Outburst, Forest Fire, Tsunami, Earthquake, Volcanic Eruption, Mass Movement, Landslide, Flood
Applications:
Geo-engineering (mapping) applications, calling for high-resolution panchromatic imagery with high pointing accuracies
Launch Date:
May 2005
Operator:
ISRO

For additional information, please visit the following external resources:

  • European Space Agency's (ESA) satellite mission database on the EOPortal database (link)
  • Committee on Earth Observation Satellites (CEOS) and ESA database (link)
  • Poster: Overview of Satellites of the International Charter "Space and Major Disasters" (link)

External tutorials on satellite technologies and Earth observation

Below you will find links to external handbooks, guides and tutorials on satellite technology.

Guides: Earth observation applications

  • CEOS Earth Observation Handbook: Satellite Earth Observations in Support of Disaster Risk Reduction (link)
  • CEOS Earth Observation Handbook: Satellite Earth Observations in Support of Climate Information Challenges (link)
  • CEOS Earth Observation Handbook: Satellite Earth Observations in Support of the Sustainable Development Goals (link)

Guides: Introduction to remote sensing

  • Introduction to radar remote sensing of the remote sensing education initiative (SAREDU) of DLR (link)
  • Tutorial on fundamentals of remote sensing of CNRS (link)
  • Tutorial on radar polarimetry (CNRS) (link)
  • Tutorial on satellite data reception (link)
  • Image interpretation quiz (link)

Guides: Didactic material on satellite technology for children and schools

  • EDUSPACE of ESA aims to provide secondary school students and teachers with a learning and teaching tool. It is meant to be an entry point for space image data, and, in particular, to a widespread visibility of Earth observation applications for education and training. (link)
  • Watching over our Planet from Space - A kit for kids (CNRS) (link)
  • Remote Sensing in schools (University of Bonn and DLR) (link)