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Expanded Capabilities In the A-Train Constellation of Earth Observing Satellites

Angelita (Angie) C. Kelly Constellation Team Manager

NASA Goddard Space Flight Center

Acknowledgement: Material presented is based on the work of the A-Train Mission Operations Working Group.

AMSR-E Science Team MeetingAugust 14-16. 2007

A-Train Status

Missoula, Montana

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TOPICS

• Afternoon Constellation “A-Train” Overview – Why Fly Constellations?

– Expanded Science Observing Capabilities

• Future Missions

• Constellation Operations Coordination

• Lessons Learned

• Other Related Topics

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Earth Observing ConstellationsWhy Fly Constellations?

Constellations provide the opportunity to make coincident,

co-registered, and nearly simultaneous science measurements

from a range of instruments.

– The satellites are aligned in their orbital positions so their instrument fields of views overlap.

– Earth science data from one satellite’s instrument can be correlated with data from another.

The whole is greater than the sum of its parts

The Earth science community has long advocated placing numerous instruments in space to study the Earth and its environment.

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2002Afternoon Constellation Evolution

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Afternoon Constellation EvolutionAura and PARASOL joined in 2004

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CloudSat and CALIPSO joined in 2006Afternoon Constellation Evolution

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Glory and OCO to be launched in late 2008Afternoon Constellation Evolution

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Afternoon Constellation Coincidental Observations

(Source: M. Schoeberl)

MODIS/ CERES IR Properties of Clouds

AIRS Temperature and H2O Sounding

AquaCloudSatPARASOL

CALIPSO- Aerosol and cloud heightsCloudsat - cloud dropletsPARASOL - aerosol and cloud polarizationOCO - CO2

CALIPSO OCO

OCO - CO2 column

Aura

OMI - Cloud heights

OMI & HIRLDS – Aerosols

MLS& TES - H2O & temp profiles

MLS & HIRDLS – Cirrus clouds

Glory

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The Afternoon ConstellationIs an International Undertaking

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Principal Investigators/Project Scientists andInternational Partners for Constellation Missions

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Investigates the Earth's water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice.

• AIRS: Atmospheric Infrared Sounder – Obtains highly accurate temperature profiles within the atmosphere

• AMSU-A: Advanced Microwave Sounding Unit – Obtains temperature profiles in the upper atmosphere (especially the stratosphere) and provides a cloud-filtering capability for tropospheric temperature observations

• HSB: Humidity Sounder for Brazil – 4-channel microwave sounder aimed at obtaining humidity profiles throughout the atmosphere.

• AMSR-E: Advanced Microwave Scanning Radiometer for EOS – Uses a twelve-channel, six-frequency, microwave radiometer system to measures precipitation rate, cloud water, water vapor, sea surface winds, sea surface temperature, ice, snow, and soil moisture

• MODIS: Moderate Resolution Imaging Spectroradiometer – Similar to Terra

• CERES: Clouds and the Earth's Radiant Energy System – Similar to Terra

Instruments

EOS Aqua

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Researches the composition, chemistry, and dynamics of the Earth’s atmosphere as well as study the ozone, air quality, and climate.

• HIRDLS: High Resolution Dynamics Limb Sounder – Observes global distribution of temperature and composition of the upper troposphere, stratosphere, and mesosphere

• MLS: Microwave Limb Sounder – Uses microwave emission to measure stratospheric temperature and upper tropospheric constituents

• OMI : Ozone Monitoring Instrument – Distinguishes between aerosol types, such as smoke, dust, and sulfates. Measure cloud pressure and coverage, which provide data to derive tropospheric ozone.

• TES: Tropospheric Emission Spectrometer – High-resolution infrared-imaging Fourier transform spectrometer that offers a line-width-limited discrimination of essentially all radiatively active molecular species in the Earth's lower atmosphere.

Instruments

EOS Aura

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PARASOL

A CNES satellite that studies the role of clouds and aerosols

(Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a LIDAR)

POLDER: Improve the microphysical and radiative property characterization of clouds and aerosols for model improvement.

Instrument

Source: CNES

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CloudSat• NASA satellite with the Cloud Profiling Radar

(CPR) instrument, a 94-GHz nadir-looking radar– Measures the power backscattered by clouds

as a function of distance from the radar.

• Developed jointly by NASA’s Jet Propulsion Laboratory (JPL) and the Canadian Space Agency (CSA).

• Will advance our understanding of cloud abundance, distribution, structure, and radiative properties.

• First satellite-based millimeter-wavelength cloud radar

– > 1000 times more sensitive than existing ground weather radars

– Able to detect the much smaller particles of liquid water and ice (ground-based weather radars use centimeter wavelengths)

Cloud Profiling Radar

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CALIPSO• Joint NASA/CNES satellite

• Three instruments:– Cloud-Aerosol Lidar with Orthogonal Polarization

(CALIOP): Two wavelength polarization-sensitive Lidar that provides high-resolution vertical profiles of aerosols and clouds

– Wide Field Camera (WFC): Fixed, nadir-viewing imager with a single spectral channel covering the 620-670 nm region

– Imaging Infrared Radiometer (IIR): Nadir-viewing, non-scanning imager

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Future Missions

Two more missions are set to join the A-Train after they launch in late 2008:

• The Orbiting Carbon Observatory (OCO) will– Provide space-based observations

of atmospheric carbon dioxide (CO2), the principal human-initiated driver of climate change.

• The Glory mission will– Collect data on the chemical,

microphysical, and optical properties, and spatial and temporal distributions of aerosols, and

– Continue collection of total solar irradiance data for the long-term climate record.

Glory

OCO

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Afternoon Constellation Operations Coordination

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A-Train Operations

• The Afternoon Constellation Mission Operations Working Group (MOWG) • Formed in 2003 to coordinate constellation operations and to ensure “safe

constellation flying” • Membership comprises science and mission operations personnel from

each mission from both sides of the Atlantic.• Each group has its own culture and philosophy on how to ensure safe

Operations.• Each mission has its own control center and orbit computation system

• SAFETY is the number one priority for constellation operations• The MOWG established baseline Constellation agreements and

guidelines that members agreed to follow.• Constellation Operations Coordination Plan• Constellation Operations Contingency Procedures

Each mission team operates independently but all mission teams are committed to keeping the constellation safe.

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• Ensure the integrity and safety of the constellation through cooperative agreements and actions

• Agree on the baseline Constellation orbital configuration

• Provide a forum for defining changes to the baseline Constellation configuration

• Facilitate coordination of multi-satellite science campaigns

• Review specific mission plans that might impact the other Constellation missions

• Provide the forum for discussing and resolving issues between member satellites

• Provide consultation support for teams proposing new missions to fly in the A-Train

Afternoon Constellation Mission Operations Working Group (MOWG) Charter

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Lessons Learned

1. Cooperation and coordination are essential to keeping the constellation safe– The various mission teams of the constellation now operate as a

coordinated and cooperative “A-Train mission team”

2. Pre-launch constellation simulations are valuable for identifying areas needing improvement– Data products and interface requirements were made consistent

• Early Science Team and high level management support is key to the success of Constellation operations

• Continued coordination between operations and science teams is critical to ensure safety

• New missions that want to join the constellation can benefit from early coordination with the A-Train MOWG

Safe Constellation operations enable unprecedented opportunities toincrease our understanding of the health of our home planet.

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AcknowledgementsAcknowledgements

The success of the Afternoon Constellation has been possible due to the:

Direction and support provided by the Project Scientists and Principal Investigators, and the

Professionalism, cooperation, and dedication of the Mission Operations teams

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Related Topics

• A-Train Data Depot

• Orbital Debris Avoidance

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A-Train Data Depot

The primary objective of Data Depot (ATDD), is to process, archive, provide access, visualize, analyze and correlate distributed atmosphere measurements from various A-Train instruments along A-Train tracks.

The Depot will enable the free movement of remotely located A-Train data so that they are combined to create a consolidated, almost synoptic, vertical view of the Earth's atmosphere.

Once the infrastructure of the Depot is in place, it will be easily evolved to serve data from all A-Train data measurements: one-stop-shopping.

URL: http://disc.gsfc.nasa.gov/atdd/

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The A-Train Data Depot GoalsThe A-Train Data Depot Goals

Provide a tool that allows A-Train sensor data to be provided with first order temporal and spatial correlations (coincidence) already performed for the scientist.

Be responsive to the data and service needs of the A-Train Cloud/Aerosol community

Provide services (i.e., expertise) that will facilitate the effortless access to and usage of ATDD data

Collaborate with scientists to facilitate the use of data from multiple sensors for long term atmospheric research

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Orbital Debris Avoidance

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Debris Avoidance

• On average, one object comes close

– Within 5 km of each A-Train mission each day

– Within 2 km of each A-Train mission once or twice a week.

• ESMO has a task with the DOD’s Joint Space Operations Center to screen all A-Train and Morning Constellation missions to ensure their safety.

• A-Train missions are in a 705 km sun-synchronous polar orbit.• 55 other objects reside in orbits with mean altitudes of 705 +/- 5

km, including, Terra, EO-1, Landsat-5 and -7, and six Iridium satellites.

• More than 1500 cataloged objects pass through this regime each day.

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• Terra performed a very small maneuver on June 21 to avoid a piece of debris from the Chinese satellite, FENGYUN

• CloudSat performed a maneuver on July 4 to avoid an Iranian satellite

• The International Space Station performed a small drag make-up maneuver on July 23 to avoid a tank of ammonia which astronauts had ejected earlier

Debris Avoidance Maneuvers During June – July 2007

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FENGYUN 1C Debris Distribution (2/15/07)• Debris threat is increasing:

– ~11,000 tracked objects >1 cm2

– 3 collisions publicly documented, 1 near EOS regime

– Over 200 objects added to NORAD catalog yearly (Ref: Liou & Johnson)

• Chinese ASAT test using FENGYUN on January 11 added significantly more debris:

– 861 km orbit altitude– 756 pieces of debris cataloged as

of February 15, 2007

Debris Environment

Several additional breakups in February caused over 1000 additional pieces of debris (see next slide)

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“… The Chinese weapon test, on Jan. 11, shattered an aging weather satellite into hundreds of bits, in what space experts describe as the worst satellite fracture of the space age.

“Soon after that, four more breakups added to the debris problem: On Feb. 2, a new Chinese navigation satellite suffered an apparent engine failure that left it in dozens and perhaps hundreds of pieces.

“On Feb. 14, an abandoned Russian engine broke into roughly 60 detectable pieces, apparently because residual fuel had exploded.

“On Feb. 18, a retired spacecraft jointly developed by China and Brazil suddenly and mysteriously broke into dozens of pieces. American experts suspect it was the victim of a collision with other space debris.

“Then on Feb. 19, a large Russian space tug exploded, apparently from residual fuel, creating a cloud of about 1,000 pieces of detectable debris.

“Orbital Debris Quarterly News, a NASA publication, noted that at least three of the four breakups appeared to have been preventable if more caution had been exercised in designing and operating the vehicles.”

Orbital Debris In The NewsNew York Times article

July 31, 2007

Source: New York Times, July 31, 2007http://www.nytimes.com/2007/07/31/science/space/31orbi.html?_r=1&ref=science&oref=slogin

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Thank you.

Questions?