The PARASOL Satellite Moving Off the A-Train's Track

Jan 04, 2010 by Angelita Kelly/Rob Gutro
An artist's rendition of the PARASOL satellite. Credit: CNES

( -- After nearly 5 years of concurrent operations with the Afternoon Constellation, known as the "A-Train," the PARASOL satellite is going on another orbit "track." The A-Train includes a number of NASA satellites that orbit the Earth one behind the other on the same track and until this month, PARASOL has been part of that train.

PARASOL is an Earth observation mission, managed by the French Space Agency (CNES). PARASOL stands for "Polarization and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar." According to CNES, it was maneuvered to leave its position inside the A-Train at 12:48 UTC, December 2, 2009.

The A-Train satellite formation currently consists of five satellites flying in close proximity: Aqua, CloudSat, CALIPSO, PARASOL and Aura. Each of these satellites cross the equator within a few minutes of each another at around 1:30 p.m. local time. By combining the different sets of nearly simultaneous observations, scientists are able to gain a better understanding its main mission, studying the important parameters related to . As an additional benefit, the A-Train satellites provide unique information about , the collective term for tropical depressions, tropical storms, hurricanes and typhoons.

The PARASOL satellite has now reached an orbit of 3.9 kilometers (2.4 miles) under the A-train, which will enable it to keep on sharing data periodically with the A-train members, while gradually leaving the A-Train neighborhood. Based on a typical decay of its orbit, it is expected to be completely out of the A-train neighborhood at the end of 2012. The CNES team will continue to coordinate operations with the A-Train Mission Operations Working Group to ensure safety.

PARASOL's measurement of aerosols is based on polarization, so is unique within the existing A-Train. Its departure leaves a data gap that will be filled when Glory (also a spectrometer) launches in 2010. Cross-calibration between Glory and PARASOL, to merge the 2 datasets into a single long-term trending dataset, will take longer with PARASOL in a different orbit.

Steven Platnick, Acting Earth Observing System Project Scientist at NASA Goddard Space Flight Center in Greenbelt, Md. said, "With its novel combination of polarimetry and multiangle capabilities, PARASOL continues to provide a unique and important perspective on cloud and aerosol properties. More important, as a strong complement to other A-Train instruments, POLDER has contributed to an unprecedented data set that will be studied for years to come."

CNES launched PARASOL into the A-Train orbit in December 2004. For the past five years, PARASOL, originally designed to be a 2-year mission, flew within ~30 seconds of the CALIPSO and CloudSat satellites.

Explore further: Scars on Mars from 2012 rover landing fade—usually

More information: For more information about PARASOL, visit:

add to favorites email to friend print save as pdf

Related Stories

NASA's CloudSat Spacecraft Arrives at Launch Site

May 17, 2005

A NASA spacecraft designed to reveal the inner secrets of Earth's clouds has arrived at Vandenberg Air Force Base, Calif., to begin final launch preparations. The CloudSat spacecraft arrived at Vandenberg fro ...

NASA Satellites Will Reveal Secrets of Clouds and Aerosols

Sep 15, 2005

Two NASA satellites, planned for launch no earlier than Oct. 26, will give us a unique view of Earth's atmosphere. CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) are undergoing final ...

Satellites illuminate pollution's influence on clouds

May 27, 2008

Clouds have typically posed a problem to scientists using satellites to observe the lowest part of the atmosphere, where humans live and breathe, because they block the satellite's ability to capture a clear, ...

NASA Releases Initial Images From CALIPSO

Jul 25, 2006

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation spacecraft known as CALIPSO is returning never-before-seen images of clouds and aerosols, tiny particles suspended in the air.

France Launches Spy Satellite

Dec 19, 2004

Arianespace has successfully launched the Helios IIA observation satellite for the French, Belgian and Spanish ministries of defense. Following a flight lasting 60 minutes and 8 seconds, the Ariane 5 launch vehicle accurately ...

Recommended for you

Europe resumes Galileo satnav deployment (Update)

Mar 27, 2015

Europe resumed deployment of its beleaguered Galileo satnav programme on Friday, launching a pair of satellites seven months after a rocket malfunction sent two multi-million euro orbiters awry.

More evidence for groundwater on Mars

Mar 27, 2015

Monica Pondrelli and colleagues investigated the Equatorial Layered Deposits (ELDs) of Arabia Terra in Firsoff crater area, Mars, to understand their formation and potential habitability. On the plateau, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.