Cloud-Aerosol Transport System (CATS) - 09.13.17

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

ISS Science for Everyone

Science Objectives for Everyone
The Cloud-Aerosol Transport System (CATS) investigation uses a light detection and ranging (LiDAR) system to measure the location, composition and distribution of pollution, dust, smoke, aerosols and other particulates in the atmosphere. CATS is mounted on the Japanese Experiment Module's Exposed Facility and is used to study the atmospheric constituents that impact global climate. By gaining a better understanding of cloud and aerosol coverage, scientists can create a better model of the Earth's climate feedback processes.
Science Results for Everyone
Information Pending

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


Principal Investigator(s)
Matthew J. McGill, Goddard Space Flight Center, Greenbelt, MD, United States

John E. Yorks, M.S., Goddard Space Flight Center, Greenbelt, MD, United States

NASA Goddard Space Flight Center, Greenbelt, MD, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
NASA Research-SMD

Research Benefits
Earth Benefits

ISS Expedition Duration
September 2014 - March 2016; March 2016 - February 2018; -

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • The Cloud-Aerosol Transport System (CATS) investigation uses a remote sensing instrument designed to provide measurements of atmospheric clouds and aerosols. The impact of clouds and aerosols (e.g., pollution, dust, smoke) on a global scale with regards to energy balance and climate feedback mechanisms is not yet fully understood.
  • A better understanding of cloud and aerosol coverage and properties is critical for understanding of the Earth system and its associated climate feedback processes. The CATS LiDAR obtains range-resolved information which can be used to assess the climate impacts of clouds and aerosols on a global scale.
  • The orbit of the International Space Station (ISS) is particularly suited to measurements of this kind, because the ISS passes over and along many of the primary aerosol transport paths within the atmosphere. The ISS orbit also permits study of diurnal (day to night) changes due to the effects of aerosols and clouds in the atmosphere – something other Earth Science satellites cannot readily obtain given their orbits.


The Cloud-Aerosol Transport System (CATS) is a light detection and ranging (LiDAR) remote sensing instrument designed to provide range-resolved profile measurements of atmospheric aerosols and clouds. The CATS instrument uses a high repetition rate laser operating at three wavelengths (1064, 532, and 355 nm) to derive properties of cloud and aerosol layers including: layer height, layer thickness, optical depth, extinction, and depolarization-based discrimination of particle type. The CATS investigation is designed to provide a combination of long-term operational science, in-space technology demonstration, and technology risk reduction for future Earth Science missions; all the while adding to the continuous history of Earth atmospheric observations.
CATS is installed on the JEM-EF to enable nadir pointing of the science package sensors and instrumentation. Once CATS is connected to the JEM-EF, it is activated via the ISS command and data handling system. Mission planning and coordination for CATS is controlled via the NASA TReK system and the Marshall Space Flight Center Payload Operations Integration Center (MSFC POIC). The CATS investigation is designed to operate on the JEM-EF for at least 6 months and a maximum of 3 years. CATS is proud to be part of NASA’s Earth Right Now campaign, which includes the launches of five NASA Earth-observing missions in 12 months–more than NASA has conducted in a single year in over a decade.

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Space Applications
An improved understanding of the makeup, structure and evolution of Earth's atmosphere can enhance spacecraft launch, landing and communications. It can also help guide future experiments investigating different atmospheres such as Mars, Jupiter, and other worlds.

Earth Applications
CATS provides continuity for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) that previously launched and now is in its extended phase. Long-term observations of Earth’s atmosphere are needed to help researchers model and predict climate changes.

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Operational Requirements and Protocols

The CATS instrumentation requires an external nadir viewing location on ISS. Power and data handling is needed to operate the investigation over long periods of time (CATS is a remote sensing instrument intended to operate continuously on-orbit, with data streaming through the Medium Rate Data Link (MRDL) interface). CATS requires no crew involvement after SSRMS installation is complete.
When on-orbit, CATS is intended for continuous, or near-continuous, operation. The investigation is commanded on and operates continuously, flowing data down through the Medium Rate Data Link (MRDL) user interface to a ground processing station at Goddard Space Flight Center (GSFC). For safety purposes the investigation (e.g., the laser) is disabled during EVA and docking events.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Results Publications

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Ground Based Results Publications

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ISS Patents

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Related Publications

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Related Websites
Cloud-Aerosol Transport System (CATS) website
Earth Right Now

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image Schematic showing a primary component breakout of the of the CATS investigation. This investigation supports a standard JEM-EF attached payload volume.
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This cross-section of the atmosphere over Africa shows clouds, dust and smoke from fires, as well as topography returned by the Cloud-Aerosol Transport System (CATS) instrument aboard the International Space Station. Image courtesy of NASA.

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NASA Image JSC2013E090269 - CATS payload Instrument Manager (Stan Scott) and Safety Rep (Phillip Adkins).

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NASA Image JSC2013e090265 - CATS investigation payload equipment.

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image Artistic representation of the Cloud-Aerosol Transport System (CATS). CATS will measure clouds and aerosols in the Earth's atmosphere. It will be mounted externally on the International Space Station.
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image NASA Image: ISS042E017407 - View of the JEM (Japanese Experiment Module) Exposed Facility (JEF) and Japanese Experiment Module Remote Manipulator System (JEMRMS) with the Cloud Aerosol Testing (CATS) in the foreground.
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