Alice is an ultraviolet imaging spectrometer for spacecraft, with one used on the New Horizons spacecraft, and another on the Rosetta spacecraft.[1] Alice is a small telescope with a spectrograph and a special detector with 32 pixels each with 1024 spectral channels detecting ultraviolet light.[2]
Alice has an off-axis telescope which sends light to a Rowland-circle spectrograph, and the instrument has a field of view of 6 degrees.[3] It is designed to capture airglow and solar occultation at the same time, and has two inputs to allow this.[4]
Overview
Alice uses an array of potassium bromide and caesium iodide type of photocathodes. It detects in the extreme and far ultraviolet spectrum, from 700–2,050 Å (70–205 nm) wavelengths of light.[5][6]
Alice is intended, among its capabilities, to detect ultraviolet signatures of noble (aka inert) gases including helium, neon, argon, and krypton.[7] Alice should also be able to detect water, carbon monoxide, and carbon dioxide in the ultraviolet.[8]
ALICE was built and operated by the Southwest Research Institute for NASA's Jet Propulsion Laboratory.[9]
Naming
Alice is named after a character in The Honeymooners (1950s television show),[10] along with another New Horizons instrument, Ralph.
Alice on New Horizons
In August 2018, NASA confirmed, based on results by Alice on the New Horizons spacecraft, the detection of a "hydrogen wall" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft which have detected a surplus of ultraviolet light determined to be coming from hydrogen.[11][12]
The New Horizons version of Alice uses an average power of 4.4 watts and weighs 4.5 kg (9.9 pounds).[13]
Examples | |||||||
Name | Wavelength Bandpass | Aperture(s) | |||||
---|---|---|---|---|---|---|---|
Human eye | 400–700 nm (approx.)[14] | 0.6 cm[15] | |||||
LORRI | 350 – 850 nm | 20.8 cm | |||||
Alice | 70-205 nm[16][17] | (two; 40 x 40 mm2 1 mm [18] |
Alice on Rosetta
On Rosetta, a mission to a comet, Alice performed ultraviolet spectroscopy to search and quantify the noble gas content in the comet nucleus.[19][20]
On Rosetta it is a 3.1 kg (6.8 lb) instrument which uses 2.9 watts.[21][22]
See also
- UVS (Juno) (ultraviolet imaging spectrometer on Juno Jupiter orbiter)
- Ultraviolet–visible spectroscopy
- List of New Horizons topics
References
- ^ "The New Horizons Alice UV Spectrometer". www.boulder.swri.edu. Retrieved 2018-10-20.
- ^ "New Horizons". pluto.jhuapl.edu. Archived from the original on 2018-05-01. Retrieved 2018-10-20.
- ^ "ALICE: The ultraviolet imaging spectrograph aboard the New Horizons Pluto mission spacecraft". ResearchGate. Retrieved 2018-12-19.
- ^ "ALICE: The ultraviolet imaging spectrograph aboard the New Horizons Pluto mission spacecraft". ResearchGate. Retrieved 2018-12-19.
- ^ Stern, S. A.; Slater, D. C.; Scherrer, J.; Stone, J.; Versteeg, M.; et al. (February 2007). "Alice: The Rosetta Ultraviolet Imaging Spectrograph". Space Science Reviews. 128 (1–4): 507–527. arXiv:astro-ph/0603585. Bibcode:2007SSRv..128..507S. doi:10.1007/s11214-006-9035-8.
- ^ Stern, S. A.; Slater, D. C.; Gibson, W.; Scherrer, J.; A'Hearn, M.; et al. (1998). "Alice—An Ultraviolet Imaging Spectrometer for the Rosetta Orbiter". Advances in Space Research. 21 (11): 1517–1525. Bibcode:1998AdSpR..21.1517S. doi:10.1016/S0273-1177(97)00944-7.
- ^ "ALICE Overview | Rosetta". rosetta.jpl.nasa.gov. Archived from the original on 2013-02-18. Retrieved 2018-10-20.
- ^ "ALICE Overview | Rosetta". rosetta.jpl.nasa.gov. Archived from the original on 2013-02-18. Retrieved 2018-10-20.
- ^ "Rosetta-Alice spectrograph to begin first-ever close up ultraviolet studies of comet surface and atmosphere". Southwest Research Institute. 10 June 2014. Retrieved 28 December 2016.
- ^ "The Museum of Broadcast Communications - Encyclopedia of Television - Honeymooners, The". www.museum.tv. Archived from the original on 2014-10-06. Retrieved 2018-12-31.
- ^ Gladstone, G. Randall; et al. (7 August 2018). "The Lyman‐α Sky Background as Observed by New Horizons". Geophysical Research Letters. 45 (16): 8022–8028. arXiv:1808.00400. Bibcode:2018GeoRL..45.8022G. doi:10.1029/2018GL078808.
- ^ Letzter, Rafi (9 August 2018). "NASA Spotted a Vast, Glowing 'Hydrogen Wall' at the Edge of Our Solar System". Live Science. Retrieved 10 August 2018.
- ^ "New Horizons". pluto.jhuapl.edu. Archived from the original on 2018-05-01. Retrieved 2018-10-20.
- ^ "What Is the Visible Light Spectrum?". ThoughtCo. Retrieved 2018-11-09.
- ^ "How to Calculate the F-stop of the Human Eye". Popular Photography. Retrieved 2018-11-09.
- ^ Stern, S. A.; Slater, D. C.; Scherrer, J.; Stone, J.; Versteeg, M.; et al. (February 2007). "Alice: The Rosetta Ultraviolet Imaging Spectrograph". Space Science Reviews. 128 (1–4): 507–527. arXiv:astro-ph/0603585. Bibcode:2007SSRv..128..507S. doi:10.1007/s11214-006-9035-8.
- ^ Stern, S. A.; Slater, D. C.; Gibson, W.; Scherrer, J.; A'Hearn, M.; et al. (1998). "Alice—An Ultraviolet Imaging Spectrometer for the Rosetta Orbiter". Advances in Space Research. 21 (11): 1517–1525. Bibcode:1998AdSpR..21.1517S. doi:10.1016/S0273-1177(97)00944-7.
- ^ 3.1
- ^ Stern, S. A.; Slater, D. C.; Scherrer, J.; Stone, J.; Versteeg, M.; et al. (February 2007). "Alice: The Rosetta Ultraviolet Imaging Spectrograph". Space Science Reviews. 128 (1–4): 507–527. arXiv:astro-ph/0603585. Bibcode:2007SSRv..128..507S. doi:10.1007/s11214-006-9035-8.
- ^ Stern, S. A.; Slater, D. C.; Gibson, W.; Scherrer, J.; A'Hearn, M.; et al. (1998). "Alice—An Ultraviolet Imaging Spectrometer for the Rosetta Orbiter". Advances in Space Research. 21 (11): 1517–1525. Bibcode:1998AdSpR..21.1517S. doi:10.1016/S0273-1177(97)00944-7.
- ^ Stern, S. A.; Slater, D. C.; Scherrer, J.; Stone, J.; Versteeg, M.; et al. (February 2007). "Alice: The Rosetta Ultraviolet Imaging Spectrograph". Space Science Reviews. 128 (1–4): 507–527. arXiv:astro-ph/0603585. Bibcode:2007SSRv..128..507S. doi:10.1007/s11214-006-9035-8.
- ^ Stern, S. A.; Slater, D. C.; Gibson, W.; Scherrer, J.; A'Hearn, M.; et al. (1998). "Alice—An Ultraviolet Imaging Spectrometer for the Rosetta Orbiter". Advances in Space Research. 21 (11): 1517–1525. Bibcode:1998AdSpR..21.1517S. doi:10.1016/S0273-1177(97)00944-7.