Alice - an ultraviolet imaging spectrometer
The New Horizons ALICE instrument is a lightweight (4.4 kg), low-power (4.4 Watt) imaging spectrograph aboard the New Horizons mission to Pluto/Charon and the Kuiper Belt. Its primary job is to determine the relative abundances of various species in Pluto's atmosphere. ALICE will also be used to search for an atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects (KBOs) that New Horizons hopes to fly by after Pluto-Charon, and it will make UV surface reflectivity measurements of all of these bodies as well. The instrument incorporates an off-axis telescope feeding a Rowland-circle spectrograph with a 520-1870A spectral passband, a spectral point spread function of 3-6A FWHM, and an instantaneous spatial field-of-view that is 6 degrees long. Different input apertures that feed the telescope allow for both airglow and solar occultation observations during the mission. The focal plane detector is an imaging microchannel plate (MCP) double delay-line detector with dual solar-blind opaque photocathodes (KBr and CsI) and a focal surface that matches the instrument's 15-cm diameter Rowland-circle.
Light can enter the telescope section through either a 40mm x 40mm entrance aperture (i.e. the airglow channel) or a stopped-down 1-mm diameter entrance aperture and flat relay mirror (i.e. the SOC) and is collected and focused by an off-axis paraboloidal (OAP) primary mirror onto the spectrograph entrance slit. The OAP has a 120 mm focal length.
The ALICE description is adapted from Slater et al. (2007) and Stern et al. (2005).
The Alice Tabs
The tabs associated with this page describe the Alice data files and how to obtain and use them.