Analyzing Interferometer for Ambient Air (ANITA) - 05.13.15

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Analyzing Interferometer for Ambient Air (ANITA) will monitor 32 potential gaseous contaminants, including formaldehyde, ammonia and carbon monoxide, in the atmosphere on board the station. The experiment will test the accuracy and reliability of this technology as a potential next-generation atmosphere trace-gas monitoring system for the station.
Science Results for Everyone
Methanol, ethanol and perfluoropropane, oh my! Crew health and safety depends on continuous monitoring of such gases and quick response to accidental gas release, extreme off-gassing of materials, or malfunctions in air systems. This experiment tested a technology for monitoring the atmosphere on the Space Station (ISS), collecting data on 32 gases, including several not previously detected or routinely measured in spacecraft. Analyzes was compared to other sources on the ground and aboard the ISS, correlating effects with spacecraft visits, crew activities, number of crewmembers, and air revitalization system operation. These results will help direct development of future air quality monitoring systems in spacecraft.

The following content was provided by Gijsbert Tan, and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
Gijsbert Tan, European Space Research and Technology Research Centre, Noordwijk, Netherlands

Information Pending

European Space Agency (ESA), Noordwijk, Netherlands
NASA Johnson Space Center, Flight Research Management Office, Houston, TX, United States
Kayser Threde, Munich, Germany

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

Research Benefits
Information Pending

ISS Expedition Duration
April 2007 - October 2008

Expeditions Assigned

Previous ISS Missions
Nothing like ANITA has been flown in space before, although other technologies have been to monitor cabin air quality.

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Experiment Description

Research Overview

  • For the safety and health of the crew, the spacecraft atmosphere needs to be continuously monitored for harmful trace gases.

  • The ANITA flight experiment will test a technology novel to spaceflight for monitoring the atmosphere on ISS.

  • In case of accidental release of harmful gaseous contaminants (large or small amounts), extreme off-gassing of materials or malfunctions in the air revitalization system, fast response by the astronauts is mandatory.

The Analyzing Interferometer for Ambient Air (ANITA) experiment is a trace gas monitoring system based on Fourier Transform Infrared (FTIR) technology. The initial flight of ANITA tested the accuracy and reliability of the FTIR technology as a potential next generation atmosphere trace gas monitoring system for the International Space Station (ISS).

ANITA was calibrated to simultaneously monitor 32 gaseous contaminants (including formaldehyde, ammonia and carbon monoxide) at low as parts per million levels in the ISS atmosphere. The hardware design - a quasi on-line, fast time resolution gas analyzer - allowed air quality to be analyzed in near real time. For this experiment, the actual ANITA analysis results (contaminant identification and concentration) were not monitored by the crew, but downlinked to the ground support team. In the future, ANITA analyses could be used by ISS crew members for detecting contaminants and immediate initiation of countermeasures, if required.

The ANITA calibration models developed prior to flight were based on a set of reference spectra of the 32 gaseous species that were considered possible contaminants. Earlier air quality analyses have determined that these trace gases may be present in the ISS cabin atmosphereThe experiment set-up allowed for rebuilding calibration models and resulting software changes to the inflight calibration codes by the ANITA ground team if a contaminant is new or present at a different concentration level. A real-time modification of the operational parameters can be uplinked to the ISS.

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Space Applications
This will lead to new atmospheric monitoring systems for future spaceflight.

Earth Applications
The ANITA application of FTIR technology provides an improved multi-component gas measurement system for various purposes, such as workplace monitoring (including airplanes and submarines), environmental monitoring, and control of industrial processes.

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Operational Requirements
In routine operation, ANITA samples the air immediately in front of the unit. In addition, it can analyze air samples gathered manually from remote locations. The remote air samples are taken applying specially provided air sampling bags and a hand pump. ANITA has two units, the Air Flushing Unit and the Interferometer. Through gas Transfer Tubes the Air Flushing Unit brings in an air sample in to the previously depressurized gas cell in the Interferometer. The gas cell is depressurized automatically using a pump. The Infrared spectrum of the air sample is measured in the Interferometer. The data is processed and stored in the ANITA A31p laptop onboard ISS. The data is downlinked daily to the ground team.

Operational Protocols
The ISS crew will start ANITA by setting up the laptop and initiating the 10-day experimental phase. ANITA will be set in Local Sampling. This sampling of air will occur in the immediate vicinity of ANITA. However, it is foreseen to have also two Non-Local samples analyzed. Non-Local Sampling involves ANITA analyzing air samples from other locations onboard ISS. Since ANITA is in a fixed location, the crew will fill an ANITA Sample Bag with air by means of a hand pump. The bag will be flushed three times with local air before the air sample is taken. The crewmember will stop the Local Sampling and connect the ANITA Sample Bag to the Air Flushing Unit. The valve on the bag is opened, allowing the sample to be drawn into the gas cell. The analysis of the Non-Local air sample is automatic. After this process is completed, the crewmember will re-initiate the Local Sampling. The data is sent through the daily downlinks to the ground team.

After the 10-day experimental phase ANITA remains operational initially for 6 months for further data logging. Non-Local Sampling may take place once per month or when needed.

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Results/More Information

ANITA operated on the ISS from September 2007 to August 2008. ANITA measured several gases on the ISS that currently are not detected by other means or are not routinely measured by real-time or archival methods. In addition, many gases in the ISS air have, for the first time, been measured with high time resolution. ANITA's air analyses were compared to results from other sources of analyses, including grab samples which were later analyzed on the ground and real-time instruments aboard ISS, such as the Volatile Organic Analyzer (VOA), Compound Specific Analyzer – Combustion Products (CSA-CP), Carbon Dioxide Monitor (CDM) and Major Constituent Analyzer (MCA). The observed gas dynamics show effects from spacecraft visits to the ISS, crew activities and the number of crewmembers present, and the functioning of the air revitalization systems (Honne et al. 2009).

ANITA measurements of carbon dioxide, methanol, ethanol and perfluoropropane (PFP) were in close agreement with grab sample readings. Carbon monoxide was detected by ANITA but not in the grab sample, despite ANITA readings that indicated carbon monoxide values were above the lower detection limit for the grab samples. Methane was detected both by ANITA and in the grab samples; however, only the two highest grab sample measurements were in agreement with ANITA. The three remaining grab samples reported only trace amounts of methane, whereas ANITA reported significantly higher amounts (Honne et al. 2009).

Additionally, ANITA has measured several gases that are not currently detectable by other means or are not routinely measured on ISS. The previously unknown presence of the gas sulphur hexafluoride (SF6), a chemical used in certain medical investigations, was discovered by ANITA in the ISS atmosphere. ANITA also detected a leak of Freon 218, also known as PFP, from the Russian air conditioner and was used to monitor the timeline of PFP concentrations in relation to Carbon Dioxide Removal Assembly (CDRA) operations and Shuttle docking. The ANITA data helped to determine that the zeolite bed in the CDRA was not effective in scrubbing the PFP leak from the air but that dilution of the ISS air after Shuttle docking did substantially reduced the level of PFP. Prior to ANITA, PFP levels in the ISS atomosphere had only been estimated (Honne et al. 2009, 2011).

Results and lessons learned from ANITA will be applied to the development of future air quality monitoring systems for ISS and future exploration missions (Honne et al. 2011).

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Results Publications

    Honne A, Schumann-Olsen H, Kaspersen K, Clausen S, Mosebach H, Kampf D, Stuffler T, Supper W, Tan G.  ANITA Air Monitoring on the International Space Station Part 2: Air Analyses. SAE International Journal of Aerospace. 2009 April; 1(1): 178-192. DOI: 10.4271/2008-01-2043.

    Stuffler T, Mosebach H, Kampf D, Honne A, Schumann-Olsen H, Kaspersen K, Henn N, Supper W, Tan G.  Advanced ISS Air Monitoring — The ANITA and ANITA2 Missions. SAE International Journal of Aerospace. 2009 Jul 12; 2009-01-2523: 8 PP. DOI: 10.4271/2009-01-2523.

    Stuffler T, Mosebach H, Kampf D, Honne A, Schumann-Olsen H, Kaspersen K, Supper W, Tan G.  ANITA Air Monitoring on the International Space Station Part 1: The Mission. SAE Technical Paper. 2008 Jun 29; 2008-01-2042: 8 pp. DOI: 10.4271/2008-01-2042.

    Honne A, Schumann-Olsen H, Kaspersen K, Mosebach H, Kampf D.  ANITA - an FTIR-based Continuous Air Quality Monitoring System on the ISS (International Space Station). Applied Industrial Optics: Spectroscopy, Imaging and Metrology, Toronto, Canada; 2011 jULY 10-14 3 pp.

    Honne A, Schumann-Olsen H, Kaspersen K, Limero TF, Macatangay AV, Mosebach H, Kampf D, Mudgett PD, James JT, Tan G, Supper W.  Evaluation of ANITA Air Monitoring on the International Space Station. SAE International Journal of Aerospace. 2009 June; 4(1): 451-466. DOI: 10.4271/2009-01-2520.

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Ground Based Results Publications

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ISS Patents

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Related Publications

    Stuffler T, Mosebach H, Kampf D, Honne A, Tan G.  The Flight Experiment Anita-A High Performance Air Analyser for Manned Space Cabins. Acta Astronautica. 2004 November; 55(3-9): 573-579. DOI: 10.1016/j.actaastro.2004.06.003. [Also: Stuffler, Timo, ‘The Flight Experiment ANITA - A High Performance Air Analyser for Manned Space Cabins’ (American Institute of Aeronautics and Astronautics, 2003)    ]

    Mosebach H, Kampf D, Stuffler T, Honne A, Odegard H, Tan G.  The Advanced Air Analyser ANITA on its Way to the International Space Station (ISS) in the Year. 55th International Astronautical Congress, Vancouver, Canada; 2004

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Related Websites

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image Pictured above are the different components that are used in the ANITA experiment. Image a courtesy of ESA.
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image NASA Image: ISS015E32200 - Flight engineer, Clay Anderson using the Sampling Pump and 2.5 Liter Gas Sample Bag for the Analyzing Interferometer for Ambient Air (ANITA) experiment in the Node 1/Unity.
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image NASA Image: ISS015E29193 - View of Expedition 15 Flight Engineer, Clayton Anderson, posing for a photo next to the Analyzing Interferometer for Ambient Air (ANITA) equipment in the U.S. Laboratory/Destiny.
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