SPOT 4
SPOT
4 is the fourth sun synchronous satellite of the SPOT series. SPOT 1,
which was launched on 22 February 1986, and SPOT 2 (launched on 22 Jan
1990), and later SPOT 3 (launched on 26 Sept. 1993) have been providing
high resolution images in two different modes (multispectral at 20m and
panchromatic at 10m). The depointing capability up to 27° off nadir
facilitates acquisition of stereoscopic images.
Images
have a width of 60 km when they are taken at nadir. The spectral bands
in multispectral mode are identical (except for the blue band which is
not on the High Resolution Instruments) to the VEGETATION spectral bands,
while in the "panchromatic" mode, the spectral band ranges from
0.61 to 0.68µm
Every
area can be covered every 26 days (cycle duration) in the same geometric
conditions, while using the off nadir capability, a mean access time of
about 2.5 days can be obtained at equator.
The
SPOT system is a cooperative effort of France, Sweden and Belgium who
are now partners with the European Commission and Italy for the VEGETATION
Programme.
| Quick
reference on SPOT 4 |
| launch
date |
24
March 1998 |
| Mission
duration |
5
yrs |
| Weight |
2760
kg |
| Payload |
1470
kg |
| Energy |
2100
w |
| Orbit
Period |
101.46
mn |
| Inclination
|
98.72°
|
| Excentricity
|
1.3
10-3 |
| Number
of revolutions per day |
14
+ 5/26 |
| Cycle
duration |
26
days |
| velocity |
7.4
km/s |
| Equator
crossing time (descending node) |
10:30
local solar time |
| Orbit
characteristics |
at
the equator |
at
45 ° latitude |
| Distance
between successive ground tracks |
2824
km |
2000
km |
| Distance
between adjacent ground tracks |
108
km |
76
km |
| Orbital
altitude |
822
km |
832
km |
| Attitude
control |
pointing |
<
0.15° |
| rate |
<
8 10-4 °/s |
| High
Spatial resolution payload : 2*HRVIR |
| Swath |
2*
60 km at nadir |
| Depointing |
up
to 27° from nadir, laterally |
| Spatial
resolution |
20
m in multispectral mode |
| 10
m in "panchromatic" mode |
| Spectral
bands |
Multispectral
mode |
0.50
- 0.59 µm |
| 0.61
- 0.68 µm |
| 0.79
- 0.89 µm |
| 1.58
- 1.75 µm |
| "Panchromatic
mode" |
0.61-0.68
µm |
SPOT 5
SPOT 5 was
launched on 3 May 2002
Click here
for a detailed description of the high resolution system.
| Quick
reference on SPOT 5 |
| launch
date |
3
May 2002 |
| Mission
duration |
5
yrs |
| Weight |
3000
kg |
| Payload |
|
| Energy |
2400
w |
| Orbit
Period |
101.46
mn |
| Inclination
|
98.72°
|
| Excentricity
|
1.3
10-3 |
| Number
of revolutions per day |
14
+ 5/26 |
| Cycle
duration |
26
days |
| velocity |
7.4
km/s |
| Equator
crossing time (descending node) |
10:30
local solar time |
| Orbit
characteristics |
at
the equator |
at
45 ° latitude |
| Distance
between successive ground tracks |
2824
km |
2000
km |
| Distance
between adjacent ground tracks |
108
km |
76
km |
| Orbital
altitude |
822
km |
832
km |
| Attitude
control |
pointing |
<
0.15° |
| rate |
<
8 10-4 °/s |
| High
Spatial resolution payload : 2*HRG + 2*HRS |
| Swath |
2*
60 km at nadir |
| Depointing |
HRG:
up to 27° from nadir laterally
HRS:
aft telescope: -20°, forward telescope: + 20° |
| Spatial
resolution |
HRG
in multispectral mode:
3
channels at 10 m,
SWIR
at 20 m |
| HRG:
2.5 or 5 m in "panchromatic" mode |
| HRS:
10 m in "panchromatic" mode |
| Spectral
bands |
Multispectral
mode |
0.49
- 0.61 µm |
| 0.61
- 0.68 µm |
| 0.78
- 0.89 µm |
| 1.58
- 1.75 µm |
| "Panchromatic
mode" |
0.49-0.69
µm |
|
