18/12/2013: Presentations given at Parasol’s End-of-mission event
CNES’s small Parasol satellite successfully completed its mission. Initially designed for a year-long mission, it stayed operational for 9 years, studying clouds and aerosols. Even though it stayed out of the spotlight, its contribution to our understanding of the climate system has been invaluable.
As the mission’s lead scientist from the LOA Didier Tanré explains, “this satellite is part of a long line of missions” and hasn’t in itself revolutionised our understanding of the climate system. But that wasn’t what it was designed for. Tanré reminds us: “it wasn’t the first!”
Scientifically speaking, Parasol’s contributions are far from insignificant. As Tanré explains, Parasol provides “information on the processes” which characterise clouds and aerosols. It unlocked “previously unobtainable data” on their properties and thus made “a significant contribution to our understanding of cloud an aerosol cycles” which plays a role in our climate system.
12/18/2013: Presentations of the event "End of Parasol mission" (in French)
- Timeline/Mission objective/Future prospects - D. Tanré (LOA)
- Measurement concept and originality - B. Fougnie (CNES)
- Study of cloud properties - F. Parol (LOA)
- Study of aerosol properties - D. Tanré (LOA)
- Use for terrestrial surface observations - F.M. Bréon (LSCE/CEA)/M. Leroy (CNES)
18/12/2013 End of the road for Parasol
Parasol’s decommissioning phase began following the end of the scientific mission on 11th October 2013. It was done in 3 stages which included additional technological experiment on the spacecraft.
The first step was to completely extract Parasol from the A-Train without endangering the remaining satellites on the same orbit. This took 3 manoeuvres of two thrust boosts each between late October and early November. The third stage was to empty remaining propellant while lowering its orbit as much as possible, in order to reduce the duration of atmospheric re-entry. This fluid passivation stage took place in November and required 5 manoeuvres of two thruster boosts each.
The third and final stage, electrical passivation, consists in shutting down the satellite’s systems. It started in early December and ended on the 18th of the same month.
11/10/2013: Payload final shutdown and end of the scientific mission
End of the line for Parasol. Decommissioning operations have begun on 11th October 2013 and should be completed by late December 2013. Acquired data archives are to be processed in 2014.
The very last image captured by Parasol: 2 shots taken above the Kamchatka peninsula between the Sea of Okhotsk to the left and the Bering Sea to the right; one shot is in natural light (left) and the other in polarised light (right)
12/2012: Parasol’s 8th anniversary
Launched on 18th December 2004, CNES’s second mission using the Myriade spacecraft bus, Parasol, has just celebrated its 8th year in space.
The Parasol mission has been a tremendous scientific and technological success. Owing to CNES engineers’ experience on both the Myriade spacecraft bus and the Polder instrument, the mission only took 5 years to design and develop, an impressively short time for a space project.
Furthermore, despite a few issues with the star tracker, the mission boasts close to 90% availability to this day. It allowed scientist to gather comprehensive data in coordination with the rest of the A-Train’s instruments for almost 5 years.
The mission’s nominal science objectives, which include determining clouds and aerosols’ radiative and microphysical properties, have been met and sometimes even surpassed.
Using quality observations and new, more sophisticated inversion methods, it is now possible to determine the size of droplets in a cloud or to gather information on aerosols even when they occur above reflective surfaces. New, unforeseen parameters emerged after analysing complementary data from the polarimeter and other A-Train instruments (including the LIDAR and the radar). These parameters include certain macrophysical properties of clouds (altitude, geometrical thickness, etc.), as well as detecting and quantifying aerosol plumes above cloudy areas.
Representation of Parasol’s ability to detect and quantify aerosol layers above cloudy areas. Shown here, the aerosol plume emitted by the Eyjafjallajokul volcano in Iceland on 8th May 2010. The colour scale shows optical thickness (accurate to 550 nm) function of particle concentration.
This anniversary is very special, as it may very well be the last. Parasol is running low on propellant and should be decommissioned in autumn 2013, when its orbital decay becomes too significant to carry on with its mission.
With such a positive track record, only one regrets remains: starting in September, scientists will have to wait 7 or 8 long years before the 3MI mission aboard EPS-SG once again provides directional polarised observation capabilities from space.
26/07/2012: The Parasol project team notifies the scientific community and particularly Parasol data users that the mission’s local time (set at 13.30 from the beginning of the mission to late 2009) is shifting
The mission has been extended well beyond the initial intended lifetime. As a result, the satellite’s inclination hasn’t been maintained for the past several years; the local time shift is now increasing rapidly into the afternoon. Parasol now flies above the equator at around 15.00 local time. The graph below shows how the satellite’s local time has shifted along the duration of the mission. This does not have any major effect on product quality but entails a significant change in solar geometry during data acquisition.
18/12/2011: Parasol celebrates its 7th year in orbit while remaining fully operational
14/11 & 16/11/2011: Parasol’s orbit is lowered, the mission goes onParasol’s orbit was lowered to 9.5 km below the A-Train by CNES’s operations team through two manoeuvres. Observations should go on uninterrupted until late September 2013.
08/11/2011: Green light from the LOS office to extend Parasol’s mission
The LOS office (Lois sur les operations spatiales/Space Operations Act) has given its approval for extending Parasol’s mission, in view of the orbit lowering planned for November 2011.
19-21/10/2011: A-Train Mission Operations Working Group meets in Biarritz, France
This year, CNES hosted the A-Train MOWG (Mission Operations Working Group) meeting. During this event, CNES presented its A-Train partner with the chosen strategy when it comes to extending the Parasol mission, as well as the timetable and parameters for the next orbit lowering operation. This operation is scheduled for November 2011 and will be carried out to comply with LOS recommendations.
22/09/2011: 6th Operations Review for Parasol at CNES’s Toulouse Space Centre
This 6th Operations Review was an opportunity to highlight the satellite and its ground segment’s outstanding operational performance, and take note of the mission extension to late 2013 (decommissioning operations included).
06/2011: CNES is now in charge of producing Ocean and Land data from Parasol
CNES’s Parasol/Polder production centre (CPP) took over production of Parasol data for level 2 and level 3 Ocean and Land data.
At CNES, the exploitation of these data began from April 14th for "Ocean" data and from June 1st for "Land Surface" data.
An archive of all these level 2 and 3 data, "Ocean" and "Land Surface", will soon be available at CNES.
26/05/2011: Mission Extension Review Steering Committee (REDEM).
The REDEM Steering Committee gave its green light for a Parasol mission extension and advises extending until late September 2013 followed before the decomissioning operations in late 2013. To follow the LOS officerecommandations, the REDEM Steering Committee asked the project team to prepare new orbit lowering operations before late 2011. The new altitude is 10 km under the A-Train constellation. The LOS officeis expected to ratify this extension.
04/04/2011: Mission Extension Review (REDEM).
End 2010, the scientific community asked for an extension of Parasol mission. CNES instructed this request and presented the results during the REDEM on April 4, 2011. Since the application of the "Loi d'Opérations Spatiales" (LOS: Space Operations Law) in December 2010, a mission exploitation extension must respect as much as possible the criteria defined by the new law and the advices emitted by the LOS bureau.
04/03/2011: NASA'S Glory Satellite Fails To Reach Orbit.
NASA's Glory Earth-observation science satellite, whose launch had been postponed to March 4th, failled to reach its orbit due to fairing seperation failure.
02/2011: French scientists all set for U.S. Glory mission.
NASA's Glory Earth-observation science satellite launch set on February 23 is postponed. French scientists are taking part in this adventure with support from CNES.
18/12/2010: Parasol celebrates its 6th year in orbit on December 18, 2010.
It has been over a year since Parasol left its position in the A-Train constellation; but the satellite continues to provide its unique observations of the directional signatures of clouds and aerosols.
According to the mission extension review held in 2010, the continuity of measurements should last until late 2011. During the first quarter of 2011, CNES will adress a new mission extension request submitted by the scientific community.
25/10-28/10/2010: International Symposium on the A-Train Satellite Constellation, New Orleans, USA
The 2010 International Symposium on the A-Train Satellite Constellation takes up on the first A-Train Symposium held in Lille, France, in 2007. It aims to provide a forum to exchange information on the latest scientific advancements using multisensor measurements from the A-Train. An additional objective of the Symposium is to better inform new and present users on recent enhancements to A-Train data sets and subtleties related to their use. Because the instruments employ different measurement techniques, fusing the observations and/or data products is often challenging. Consequently, another important objective is to highlight key issues and strategies for combining the diverse measurements.
104/10-06/10/2010: MOWG in Orlando, Florida, USA
24/09/2010: 5thParasol products Exploitation Review on 24 September 2010, at CNES offices in Toulouse
02/12/2009: Parasol gets off the train
After collecting observations synchronous with the other satellites from the A-Train for almost 5 years, Parasol was moved to a lower orbit (3.9 km under the A-train) at 12:48 UT on December 2, 2009. The maneuver was performed by the CNES flight operations teams. The microsatellite Parasol had joined the A-Train constellation in early February 2005.
Parasol orbit tracks have been slowly drifting eastward these past few months, due to insufficient fuel supplies that prevented Parasol to be part of the last inclination maneuver performed by the other A-Train satellites in Spring 2009. However, observations were still in phase with the other sensors. On the new orbit, observations from Parasol will no longer be simultaneous with the other sensors, except for only a few days at regular intervals.
CNES's decision to position Parasol to a lower orbit was motivated by safety reasons to minimize the risk of collision, should Parasol begin to fail. While the expected duration of the Parasol mission was 2 years, it will reach 5 years in March 2010.
On December 18, 2009, Parasol will celebrate its 5th anniversary in orbit, alone, yet pursuing its mission of observation of clouds and aerosols.
18/12/2008: Fourth launch anniversary for Parasol!
11/2008: Parasol in the press: interview of the mission PI (in french).
10/2008: A-TRAIN operational coordination meeting (MOWG) on October 8th, 9th and 10th, 2008 in Norfolk, Virginia (USA).
06/2008: Third Parasol products Exploitation Review on June 19th, 2008, at CNES Toulouse
06/2008: Third Parasol space segment Exploitation Review on March 27th and 28th, 2008, at CNES Toulouse
10/2007: An "A-Train Lille Symposium 2007" was held in Lille - Grand-Palais - from October 22 to 25, 2007.
The themeof this international meeting was: "Bringing together A-train observations and modelling to understand aerosols and clouds"
06/2007: Second Parasol Exploitation Review
03/2007: Parasol in the Eye of the storm.
01/2007: End of AEROSOL and CLOUDS Level 2 and 3 reprocessing at ICARE.
12/2006: A-train operational coordination meeting at NASA
11/2006: Parasol level-1 Archive (Version 3) reprocessing completed.
Products level 1C, corresponding to level 1 extracts over Calipso track are also available from June 2006. See examples here.
07/2006: Parasol Scientific Products are available to users
18/05/2006: Parasol Validation Review was held on May 18th, hosted by the Laboratoire d'Optique Atmosphérique in Lille.
The assessment of the various aerosol and cloud parameters was successfull and the distribution of the data to the users has been authorised by D.Tanré, PI of the mission.
11/05/2006: 1st Parasol REVEX (EXploitation REView)
The space segment part was held on May 2006, 11th and the products part was held on the 12th.
During this REVEX, one could note the good course of the exploitation since the in flight commissioning and the satisfaction shown by scientific teams about Parasol products quality. It was thus decided to carry on the exploitation as long as the system can supply good quality data. The propellent budget enables to envision to maintain Parasol in the A-train constellation until spring 2009, even if no guaranty can be given on the duration of the operations after the "nominal" lifespan of the satellite.
CNES technical teams managed to solve the few problems at the beginning of operations, and to obtain a mission availability hugely higher than the objective (availability of 95 % for an objective of 75 %). The efficiency of the operational teams largely contributes to the success of the mission.
11/2005: Parasol level-1 products reprocessing completed.
The archive starts from March 2005, 4th.