A host of observation devices in orbit

The study of our planet is more than ever a global concern. Every country with a space observation capability makes its data available to foreign researchers. However, this does not prevent special forms of collaboration from being set up. Here is a very small selection that does not include those early pioneers of very high resolution satellite imagery for civilian purposes, Quickbird and Ikonos (1999).

Mount Fuji Mount Fuji, the first image sent by Japan’s ALOSsatellite in 2006. At the bottom of the picture you can see the roads and rivers in the Kofu basin and Motosu Lake.
Calipso, one of the six advanced observation  satellites in the <em>Afternoon-train</em>. Its state-of-the-art technology is  expected to advance our understanding of climate mechanisms. Calipso, one of the six advanced observation satellites in the Afternoon-train. Its state-of-the-art technology is expected to advance our understanding of climate mechanisms.

A brief overview

Alos - This Japanese Earth observation satellite was placed in orbit in January 2006. It scans the planet day and night in all weathers by means of its PALSAR synthetic aperture radar and panchromatic remote-sensing instrument for stereo mapping (PRISM).

Quikscat - Launched by NASA in 1999, its chief instrument, a scatterometer, provides information on winds on the Earth’s surface, both on the ground and above the oceans. This provides an opportunity to study various interactions between the atmosphere and Earth.

Irs-P6 - Also called RESOURCESAT-1, the Indian Space Research Organisation (ISRO) launched this remote sensing device. The Indian space agency also placed IRS-P3 in orbit in 1996. This Earth observation satellite is equipped with an MOS (Modular Optoelectronic Scanner).

Terra Sar X - This radar satellite by the German company Infoterra is due to become operational in 2007.

Kompsat-1 - This South Korean satellite, the first in a series of high resolution optical observation satellites, was put into orbit in 1999. Kompsat-2 (KOrean MultiPurpose SATellite), a very high resolution device by the Korean Aerospace Research Institute (KARI), was successfully launched on 28 July 2006. It provides images with one-metre resolution.

Formosat-2 - This Taiwanese satellite by the National SPace Organization (NSPO) is of European design. It was manufactured by EADS-Astrium and provides high resolution observations (2 metres) with a daily revisit capability!

Scisat - This tool assists a team of Canadian and international researchers to improve their understanding of the problem of the diminishing  ozone layer, by focusing on the changes occurring over Canada and in the Arctic. It has been in orbit since 2003.

Terra - This American device, which was launched in 1999, contains five scientific instruments, including a spectroradiometer developed jointly with Canada. It is the ‘morning’ counterpart of America’s Aqua ‘afternoon’ satellite, which forms part of the A-Train.

Space train

Six scientific Earth observation satellites produced jointly by three countries (United States, France and Canada) travel one after the other on a single sun-synchronous orbit. This space caravan is called A-Train (afternoon train) because its six satellites cross the equator a few minutes apart at around 13:30 local time). The A-Train is an exceptional space observatory combining all the active and pasresearch  sive measurement techniques required to better understand the inner workings of climate mechanisms. The satellites in the A-Train are: Aqua (NASA, 2002), Aura (NASA, 2004), Parasol (CNES, 2004), Calipso (NASA/CNES) and Cloudsat (NASA/ASC), both of which were launched in 2006, and to which will be added Oco(NASA) in 2008.

The next generation already in the pipeline

In the future, remote sensing will need to meet three requirements: higher resolution (both spatial and spectral); more agile satellites capable of quickly pinpointing a target; a higher revisit time to allow daily monitoring of changes in a situation on the ground.

Between now and the end of 2008, Digitalglobe should have at its disposal a new device combining all these qualities. Worldview-1 will orbit with unprecedented speed and agility, revisiting a single site on the ground every 1.7 days, whilst providing images with 50 centimetre resolution. This is a first for a civilian satellite.