The SOLCON Instrument
The mass of the SOLCON experiment is 9.962Kg. Its power consumption is 13.6W and its date rate is 60 bits per second.
It is composed of two parts : the Digital Processing Unit (DPU) providing the interface to the ATLAS pallet and the Absolute Radiometer with its electronics .
SOLCON is a differential absolute radiometer with two channels. The incident radiative energy absorbed in a cavity is compared to electrical energy generated by the Joule effect, taking into account the nonequivalence of energies, as well as the geometric, thermal, optic and electrical characteristics of the instrument.
When the SOLCON radiometer is pointed toward the Sun, one shutter of the cavity is opened. The heat balance system compensates for the added heat until the heatfluxes are again balanced between the open and the closed cavities. The shutter is then closed, and power is adjusted to its original value automatically. The difference in the power required to maintain a heat balance between the two cavities during open and closed operations in a function of total solar radiation.
The SOLCON/DIARAD radiometer for the ATLAS missions is identical to the SOVA-I/DIARAD radiometer flown on the European Retrievable Carrier (EURECA). They are improved versions of the absolute radiometer flown on SPACELAB 1. Both SOLCON and SOVA 1 have been designed to provide the ultimate radiometric accuracy consistent with the state of the art metrological usage. The incertitude on the accuracy is evaluated to be less than ± 0.1% ; the data resolution is 22 bits.
A Entrance aperture of the double photometer
B Shutter of left channel of the absolute radiometer
C Main cover of SOLCON
D Entrance aperture of the Sunpointing sensor
E SOLCON (absolute radiometer and sensors box)
F Entrance aperture of the IRMB absolute radiometer (right channel)
G View limiting area
H Sensitive aperture of right channel
I Cavity (right channel)
J Heat flux sensor (right channel)
K Heat sink of heat balance sensor
L SOLCON (Digital Processing Unit)
M Power plug
N Command / Data plug
O Bounding pin
P Vent valve
Q Data cable
R Power cable
S Timer interface module
T Processor module
U Backup processor module
V User interface module
W Spacecraft interface module
X Left/right channel separation
Y RS232 connector
Z Absolute radiometer electronics