IAPS instruments and projects for Solar System's exploration

About VIMS

The Visible and Infrared Mapping Spectrometer (VIMS) is a Remote Sensing Instrument that is actually made up of two cameras in one: one is used to measure visible wavelengths, the other infrared. The scientific objectives are mainly focused on Saturn and Titan atmospheres, observation of Titan surface through narrow spectral window in the NIR, and identification of surface composition of small satellites, rings, and asteroids observed during the cruise phase.

How does VIMS work?

VIMS is designed to work over wavelengths between 300 and 5100 nm, taking pictures in 352 different colors at the same time. VIMS is, in essence, a very special color camera, because of the KIND of color it captures.
In analogy to the human eye, VIMS is sensible to a wider color range thatn the human eye (380 – 620 nm) and  far more accurate in determining the precise wavelength of the light that strikes it.
In other words, VIMS can simultaneously give images and spectra, wich is relevant for the mineral and compounds identification.
VIMS has 2 separate channels: the infrared (US made) and the visible (Italy made) sensor.

VIMS Scientific objectives

VIMS measures reflected and emitted radiation in the visible and infrared light, to learn more about the composition of moon surfaces, the rings, and the atmospheres of Saturn and Titan. VIMS also observes the sunlight and starlight that passes through the rings to learn more about ring structure. VIMS can determine the compositions, temperatures and structures of these objects. With VIMS, scientists also plan to perform long-term studies of cloud movement and morphology in the Saturn system, to determine the planet’s weather patterns. Also fascinating, will be VIMS’s role in observing the minor building blocks of life. Called “pre-biotic” materials, VIMS will measure the locations where they are found, and under what conditions, to possibly provide clues about the origins of life. VIMS will also study lightning, and, throughout the 40 planned orbits around Saturn, the planet’s 30 known moons.

To know more about VIMS V

The visible channel produces multispectral images spanning the spectral range 0.3-1.05 micrometers over 96 spectral bands. The VIMS-V consists of an optical head electrically coupled to an electronics box. Both boxes are mounted directly o an aluminium pallet adjacent to the infrared channel on the remote sensing platform of the Cassini spacecraft. The optical head, shown in figure 1, consists of two assemblies, the telescope and the spectrometer, which are developed and tested independently and in parallel. These two assemblies are further divided into separate testable units. The telescope’s optical components are mounted on an optical bench that is supported by internal kinematics mounts. the bench and all of the components are are aluminium, which makes the assembly athermal with regard to performance. a calibration unit is inserted into the + Z side of the telescope near the base of the baffle. The scan unit, which supports the primary mirror with ultra sensitive flexural pivots, is actually controlled from the electronics box ( VIMS-V optical head). The spectrometer is flange mounted to the telescope assembly at the slit plane. The spectrometer incorporates a kovar packaged focal plane assembly (FPA), proximity electronics, and passive. The housing and support structures are aluminium but the grating is NG5 black glass, which was necessary for groove fabrication to archive optimum performance. The cylindrical FPA, which packages the CCD and optical filter window, is inserted into a cup- shaped sorties of tungsten strips that insulate it from the spectrometer housing while coupling to the passive cooling system. The FPA has three brazened kovar mounting studs to secure it to the cold finger; it is thermally coupled to the cold finger by electrically insulating Stycast epoxy. The cold finger consists of a TZM (molibdium) cross support structure from which protrude overlapping copper foils that provide a compliant thermal path to the radiator plate mounted on the top of the optical head. On the opposite side of the box, below the optical bench and spectrometer, is located the the shielded proximity electronics to drive the CCD. An insulated cable couples the electronics to a PCB secured to the cold finger support structure. From PCB protrude fine wires that connect to the the CCD pins. This complex thermal-mechanical-electrical interface is necessary to survive an average of 10 Gcs (600 Gs peak) expected during the launch. The temperature of the VIMS optical pallet, to which VIMS-V boxes are thermally coupled, is controlled by the spacecraft. The VIMS-V passively maintains a stable temperature range through the us