Around 7pm CET [1800 UTC] on 28 January 2004, ESA’s Envisat spacecraft completed
its ten thousandth orbit of the Earth — travelling a distance of 450 million
kilometres since launch, equivalent to taking a trip to Mars.

Envisat orbits our planet every hundred minutes, moving at a velocity of more
than seven kilometres per second.

This lorry-sized spacecraft is the most complex environmental satellite ever
launched, with ten different instruments mounted on its hull to study Earth’s
land, oceans and atmosphere.

These instruments were developed and built by scientists and industrial teams
from all across Europe.

They include the Advanced Synthetic Aperture Radar (ASAR) that sees through
clouds and darkness to continuously return radar pictures and the Medium
Resolution Imaging Spectrometer (MERIS) imaging ocean colour and land cover.

Envisat’s Advanced Along-Track Scanning Radiometer (AATSR) records global ground
and sea surface temperature, while the Radar Altimeter-2 (RA-2) measuring
surface height to an accuracy of a few centimetres. A trio of atmospheric
instruments map trace gases and pollutants.

Envisat completed its latest milestone as it passed over the equator 800 km
above the middle of the Indian Ocean.

During its ten thousandth orbit, as for any of its 14 daily orbits, Envisat was
using all of its ten instruments to gather information about the world below it,
and the satellite ground segment generated about ten gigabytes of data products.

Next month Envisat will have spent two years in orbit: it was launched on 28
February 2002 by Ariane-5 rocket from the Kourou spaceport in French Guiana.

Dozens of images acquired by Envisat instruments since then are collected in
ESA’s Multimedia Gallery.

Related articles

* Iceberg’s end caught by Envisat

* Envisat images delivered to Antarctic eclipse spotters

* Over land, sea and air, users give MERIS high marks

* Near-real time ozone forecasting made possible by Envisat

* Envisat radar altimetry tracks river levels worldwide

Related links

* Envisat Mission

* What is Envisat?

* Where is Envisat now?

* Envisat Instruments

* Envisat images