An evaluation of a bake-out of the ACIS instrument on the Chandra X-Ray Observatory

Plucinsky, Paul P.; O’Dell, Stephen L.; Tice, Neil W.; Swartz, Douglas A.; Bautz, Marshall W.; DePasquale, Joseph; Edgar, Graham J.; Garmire, G. P.; Giordano, Rino; Grant, Catherine E.; Knollenberg, Perry; Kissel, Steve; LaMarr, Beverly; Logan, Richard F.; Mach, Martin; Marshall, Herman L.; McKendrick, Leon; Prigozhin, G.; Schwartz, D.; Schulz, Norbert S.; Shropshire, Dan; Trinh, Tan D.; Vikhlinin, A.; Virani, S.

doi:10.1117/12.552029

Cited by 12 publications

(4 citation statements)

References 13 publications

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“…ACIS has two separate filters, one for the Imaging array, OBF-I, and one for the spectroscopy array, OBF-S. For diagrams and pictures of the flight hardware, see the figures in Plucinsky et al (2004). 13 Both OBFs are secured to the top surface of the ACIS Camera Body (CB). The OBFs have no active thermal control but respond to the environment around them.…”

Section: Obf and Camera Body Temperaturesmentioning

confidence: 99%

The complicated evolution of the ACIS contamination layer over the mission life of the Chandra X-ray Observatory

Plucinsky

Bogdán

Marshall

et al. 2018

Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

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The Chandra X-ray Observatory (CXO) was launched almost 19 years ago and has been delivering spectacular science over the course of its mission. The Advanced CCD Imager Spectrometer (ACIS) is the prime instrument on the satellite, conducting over 90% of the observations. The CCDs operate at a temperature of -120 C and the optical blocking filter (OBF) in front of the CCDs is at a temperature of approximately −60 C. The surface of the OBF has accumulated a layer of contamination over the course of the mission, as it is the coldest surface exposed to the interior to the spacecraft. We have been characterizing the thickness, chemical composition, and spatial distribution of the contamination layer as a function of time over the mission. All three have exhibited significant changes with time. There has been a dramatic decrease in the accumulation rate of the contaminant starting in 2017. The lower accumulation rate may be due to a decrease in the deposition rate or an increase in the vaporization rate or a combination of the two. We show that the current calibration file which models the additional absorption of the contamination layer is significantly overestimating that additional absorption by using the standard model spectrum for the supernova remnant 1E 0102.2-7219 developed by the International Astronomical Consortium for High Energy Calibration (IACHEC). In addition, spectral data from the cluster of galaxies known as Abell 1795 and the Blazar Markarian 421 are used to generate a model of the absorption produced by the contamination layer. The Chandra X-ray Center (CXC) calibration team is preparing a revised calibration file that more accurately represents the complex time dependence of the accumulation rate, the spatial dependence, and the chemical composition of the contaminant. Given the rapid changes in the contamination layer over the past year, future calibration observations at a higher cadence will be necessary to more accurately monitor such changes.

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Section: Obf and Camera Body Temperaturesmentioning

confidence: 99%

The complicated evolution of the ACIS contamination layer over the mission life of the Chandra X-ray Observatory

Plucinsky

Bogdán

Marshall

et al. 2018

Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

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“…Indeed, because molecular contamination might blind and damage observation instruments, optical communications, thermo-optical properties of coatings or/and solar cells, it is a major risk that must be controlled at every step of the life duration of satellites. Numerous space missions faced issues due to molecular contamination [2][3][4][5][6][7]. That is why during the process of satellite integration, the intervention of contamination engineer is needed to validate the integration progress.…”

Section: Introductionmentioning

confidence: 99%

Detection and characterization of contamination with fluorescence spectroscopy

Gouisset¹,

Rioland

Bourcier

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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In the field of failure analysis and in particular molecular and particulate contamination, being able to detect any trace of contaminants during the integration of an orbital spacecraft is crucial. In this context, fluorescence allows not only to detect but also to discriminate contaminants. We studied the fluorescence response of two epoxy adhesives, typical sources of spacecraft contamination in orbit with a portable broadband hyperspectral instrument (UV-Vis-NIR) developed in collaboration with the CNES and Intraspec Technologies, but also with a commercial spectrofluorometer. These measurements had two objectives, evaluate the performance of our hyperspectral instrument in order to identify prospect of improvement, but as well study the pertinence of fluorescence signature study in the contamination field. The first goal brings out that the hyperspectral instrument is capable of imaging the scene and allows us to extract fluorescence spectra from the image, but it still needs development, especially in term of sensitivity in UV range. The second goal shows promising results. Fluorescence studies with the spectrofluorometer emphasize that fluorescence spectra are specific to the chemical nature of the contaminant, which allows us to clearly discriminate them.

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“…Despite stringent contamination controls, the film is 30 times thicker than specified, yet totals < 0.5 g in the 5-tonne Observatory! Project Science supported an extensive CXC-led investigation 48 of this anomaly and potential approaches for dealing with itincluding baking the ACIS instrument with on-board heaters designed for this purpose. Based upon previous experience and extensive ground testing, the ACIS Team and NGST concluded that a bake would be safe for the ACIS.…”

Section: Operationmentioning

confidence: 99%

The role of project science in the Chandra X-ray Observatory

O’Dell

Weisskopf

2006

SPIE Proceedings

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The Chandra X-ray Observatory, one of NASA's Great Observatories, has an outstanding record of scientific and technical success. This success results from the efforts of a team comprising NASA, its contractors, the Smithsonian Astrophysical Observatory, the instrument groups, and other elements of the scientific community-including the thousands of scientists who utilize this powerful facility for astrophysical research. We discuss the role of NASA Project Science in the formulation, development, calibration, and operation of the Chandra X-ray Observatory. In addition to serving as an interface between the scientific community and the Project, Project Science performed what we term "science systems engineering". This activity encompasses translation of science requirements into technical requirements and assessment of the scientific impact of programmatic and technical trades. We briefly describe several examples of science systems engineering conducted by Chandra Project Science.

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An evaluation of a bake-out of the ACIS instrument on the Chandra X-Ray Observatory

Cited by 12 publications

References 13 publications

The complicated evolution of the ACIS contamination layer over the mission life of the Chandra X-ray Observatory

The complicated evolution of the ACIS contamination layer over the mission life of the Chandra X-ray Observatory

Detection and characterization of contamination with fluorescence spectroscopy

The role of project science in the Chandra X-ray Observatory

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