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REFIR-PAD
first measurements, Teresina, Brazil, 30 June 2005 --->
NEWS - CNR (15/12/2005) (in Italian)--->
Stratospheric
balloon campaign: Teresina, Brazil, June 2005 --->
Ground-based
campaign, Testa Grigia, Cervinia, 3489 m a.s.l., March 2007 --->
The REFIR (Radiation
explorer in the far infrared) project is a study, funded by
European
Union, of feasibility of a novel space-borne instrument that will
measure the atmospheric spectral radiance of the Earth in the broad
spectral range 100-1100 cm-1 from space with
sufficient spectral resolution (0.5 cm-1) and
signal-to-noise ratio (SNR > 100).
The
main scientific objectives of the REFIR experiment
are the measurement of the outgoing FIR radiation at the top of the
atmosphere and the improvement of our knowledge of the principal
drivers of this flux, e.g. temperature structure, water vapour, and
clouds throughout the troposphere-surface system.
The REFIR concept consists of a far
infrared FTS as the core instrument, of an embedded imager
operating in an infrared 'window', sharing the same bore-sight as FTS,
for scene/cloud signature identification in the FIR, of an add-on
imager to provide multi-channel imagery, and of an absolute
single-pixel radiometer with a single broad-band channel, used to
measure the emitted radiation contextually with the spectral
measurements.
The
integration of all the systems leads to a very compact satellite
instrumentation, working at room temperature, with an estimated overall
mass of 70 kg and a power consumption of 80 W, including electronics.
The overall data rate toward the ground station is foreseen to be of
170 kbps before on-board data compression.
Status of the project
The REFIR
EU project started with the
feasibility study funded by European Union (EU) from January
1997 to
April 2000. The activities included the Pre-Phase A (1997), the Phase-A
(1998), and the Phase-B0 (1999) for the payload and the Pre-Phase A for
the ground segment.
The development
of a prototype, called REFIR-BB,
has been funded in 2000-01 by ASI with the project called
“R&D
bread-board for a FTS to remotely sense the rotational water vapour
band
(100-1000 cm-1)”. In the first year of activity the hardware
of the prototype has been developed.
In 2001, the
project has been proposed, and it is now under evaluation, to the
Italian Space Agency (Agenzia Spaziale Italiana, ASI) for the “Small
Mission” Program.
One of the main
concern of the design of the REFIR instrument is the beam splitter (BS)
efficiency. Currently there are not available space-qualified BS
components able to meet the REFIR requirements. To solve this problem,
a
study, called REFIR
Beam Splitter Pre-development,
has
been funded in 2001-03 by the European Space Agency (ESA) for
the
development of
polarising BS covering the spectral range from 100 to 1100 cm-1
In perspective a
prototype of this instrument could be deployed for ground-based
campaigns (at high altitude) or it could be flown on aircraft or
balloon
platforms.
A second FTS prototype,
called REFIR-PAD (REFIR-Prototype
for Applications and Developmet) has been developed for
stratospheric balloon applications. The first flight was
performed on June, 30th 2005 from the CNES base located near Teresina
in Brazil.
The results confirm experimentally the measurement capabilities and
supply the first spectral measurement with wide band coverage of the
Earth's atmospheric emission toward space. |
