Symposium on Remote Sensing for Resources Development and Environmental Management/Enschede/August 1986 
© 1987 Balkema, Rotterdam. ISBN 90 6191 674 7 
The second generation high resolution satellite systems: First results 
of the SPOT 1 satellite 
Gérard Brachet 
SPOT IMAGE, Toulouse, France 
ABSTRACT: The first in the series of SPOT Remote Sensing satellites was launched on February 22nd, i986. 
After successful orbit injection and attitude control manoeuvering, the first images from its two High Resolution 
imaging instruments (HRV) were received on February 23rd, confirming the proper performance of all systems 
on-board the spacecraft. A two-month period of in-flight acceptance tests and ground systems operations was 
conducted before operational commissioning of the SPOT 1 spacecraft. Image quality measurements confirmed the 
excellent radiometric and geometric qualities of panchromatic and multispectral data produced by the whole 
system. 
Commercial distribution of the images started on May 6, 1986 with both the Toulouse/Aussaguel and Kiruna 
(Sweden) receiving stations collecting worldwide data through the on-board tape recorders. More than 125 000 
60 x 60 km scenes were already collected by mid August, 30 % of them with acceptable cloud coverage. In 
addition, two direct read-out stations in Canada started routine operations in June, providing real time coverage 
of Canada and the United States. 
Preliminary analysis of SPOT 1 images confirm their expected usefulness for applications in cartography, land 
use and vegetation mapping coastal studies, agriculture, urban planning, etc. Their high geometric resolution and 
excellent radiometric accuracy combined with frequent coverage of selected sites demonstrate a significant 
improvement over previous land remote sensing satellites. 
RESUME : Le premier de la série des satellites de télédétection SPOT a été lancé le 22 février 1986. Après 
une injection sur orbite et diverses manoeuvres d'orientation, les premières images réalisées par ses deux 
instruments à haute résolution (HRV) furent reçues le 23 février, confirmant le fonctionnement parfait de tous 
les systèmes à bord du satellite. 
Une période de deux mois fut consacrée à la recette en vol et au rodage des opérations au sol avant de 
déclarer le système opérationnel. 
Les mesures de qualité des images confirmèrent les performances excellentes des données panchromatiques et 
multispectrales produites par le système dans son ensemble. 
La distribution commerciale des images commença le 6 mai 1986, les deux stations principales de réception 
de Toulouse/Aussaguel et de Kiruna (Suède) recevant les images acquises sur l'ensemble de la surface du globe 
grâce aux deux enregistreurs de bord. Plus de 125 000 scènes de 60 x 60 km étaient déjà acquises et archivées 
à la mi-août 1986, dont 30 % présentaient une couverture nuageuse acceptable. De plus, les deux stations de 
réception directe mises en oeuvre par le Canada à partir de mi-juin permettent depuis cette date d'assurer la 
couverture du Canada et des Etats Unis en télémesure directe. 
L'analyse préliminaire des images SPOT confirme l'intérêt qui avait été soulevé lors des campagnes de 
simulation pour de nombreuses applications telles que la cartographie, topographique et thématique, les études 
côtières, l'agriculture, l'urbanisme, etc... Leur haute résolution géométrique et leur excellente précision 
radiométrique, combinées avec la répétitivité élevée d'observation de certains sites sélectionnées, mettent en 
lumière le progrès significatif que SPOT représente par rapport aux satellites de télédétection précédents. 
1 - SPOT 1 launch and early orbital operations. 
The launch of SPOT 1, the first of a series of 
SPOT high resolution remote sensing satellites was 
initially scheduled for November 1985. Following the 
failure of the V 15 Ariane launch in September 
1985, various modifications had to be implemented 
on the third stage engine, thus delaying the V-16 
launch until February 1986. 
The launch took place during the night of 
February 21st to 22nd at 0145 Universal Time 
(10.45 p.m. on the 21st in French Guyana). The 
launch window was very narrow (10 minutes) 
because of the constraint of reaching a 10.30 a.m. 
local time for the descending node of the 
sun-synchronous orbit. 
The Ariane 1 rocket took off without a hitch 
at the begining of the launch window, carrying 
SPOT 1 together with the Swedish Scientific 
satellite VIKING. 
After the end of the third stage propulsion 
phase, SPOT 1 was separated from VIKING which 
was later injected on a highly eccentric orbit. 
Attitude manoeuvering and solar generator 
deployement on board SPOT took place during the 
next 40 minutes with ground control stations 
located in Greenbelt (Maryland), Fairbanks (Alaska) 
and Katsuya (Japan) relaying to the control center 
in Toulouse the housekeeping telemetry. 
This critical phase went smoothly with all systems 
on board performing as expected, with the only 
exception of a solar generator microswitch which 
did not work. Tracking data confirmed that the 
orbit injection parameters were very accurate: 
apogee at 833 km against 836 and perigee at 
818 km against 817. Inclination was 98.77 degrees 
against 98.74 degrees, thus avoiding an inebriation 
correction before starting the SPOT 1 imaging 
mission. The very small semi major axis and 
eccentricity corrections needed to circularize the 
orbit were performed a week later. 
With all systems on board performing flawlessly, 
the SPOT mission control center in Toulouse was 
able to load the first imaging schedule in the 
on-board computer during the evening passes of the 
satellite above the Toulouse/Aussaguel command 
station. 
Thus the first images from the two SPOT 
imaging instruments (High Resolution Visible, H.R.Vs) 
were received in the Aussaguel X-Band receiving