1. Some Programmatic Comments
Hal Maring
A-Train Program Scientist
NASA Headquarters

2. Who is responsible for all this?
Symposium Program Committee:
Matthew Lebsock
Deb Vane
Liz Juvera
Howard Barker
David Crisp
Bryan Duncan
Hal Maring
Lazaros Oreopoulos
Jacques Pelon
Steven Platnick
Jerome Riedi
Graeme Stephens
Pierre Tabary
Didier Tanre
Chip Trepte
Tobias Wehr

3. Content of the Symposium
Clouds, Radiation and Hydrology (1)
Atmospheric Composition and Carbon (1)
Clouds, Radiation and Hydrology (posters)
Aerosols (1)
Clouds, Radiation and Hydrology (2)
Aerosols and Atmospheric Chemistry and Carbon (posters)
Weather
Special Session
Special Session, Weather & Applications, Data and Other Topics (posters)
Discussion – Future Constellations: Challenges and Opportunities
Atmospheric Composition and Carbon (2)
Clouds, Radiation and Hydrology (3)
Aerosols (2)
Two Special Topical Lectures: Graeme Stephens and Bruce Wielicki

4. Expected Close Approaches
Assuming TanSat does not perform a maneuver, it will pass the A-Train on the following dates:
20 Apr 2017 – OCO-2
23 Apr 2017 – CGOM-W
30 Apr 2017 – Aqua
1 May 2017 – CALIPSO
4 May 2017 – CloudSat
11 May Aura
(Locations based on relative equator crossing times)
Response:
If the TanSat approach is close, then the A-Train satellites will try to postpone any maneuver until after the approach.
If the A-Train satellite has to maneuver, then a communication will be initiated via the State Department.

5. A-Train Satellite Longevity
DRAFT from Sept 2016 MOWG
Senior Review
CloudSat
GCOM-W1
OCO-2
MOWG Meeting
Aura
CALIPSO
Aqua
IAM
Approved Ops
Possible Extended Ops
End of Mission Ops
Proposed IAMs
2017
2018
2019
2020
2021 ?
1. Not necessarily sensor longevity

6. Possible Changes in the A-Train Configuration
As missions deplete the fuel allocated for orbit maintenance, they may skip some or all of their annual inclination corrections and let their orbits drift
CALIPSO and Aqua will be the first two missions in this situation
Mission planners can then execute one of two options:
Keep the temporal separation with respect to the anchor satellite (Aqua), and let their ground tracks drift eastward (later in the afternoon) or
Maintain their ground tracks and decrease their temporal separation (if in front of Aqua) or increase their temporal separation (if behind Aqua)
How do these choices affect Science products produced from 2 (or more) A–Train satellites?

7. Example: CALIPSO/CloudSat/OCO-2
Aqua
GCOM W1
OCO-2
CALIPSO
CloudSat
Aura
MLTAN
Aqua
GCOM W1
OCO-2
CALIPSO
CloudSat
Aura
MLTAN
Two Options
Change ground track
Change temporal separation ?
Drift Later
Change Temporal Separation

8. Considering A-Train Orbit Change
MOWG Change Request #
Submitter
Description
Status /
Comments and Due Date 17
M. Vincent
Reduce the size of the Constellation Envelope
Submitted – April 29
Revision submitted – May 31
Status – On hold. The topic is to be re-presented at the Fall 2016 MOWG meeting
4, 6 or 8 km?
OCO-2
GCOM-W1
CALIPSO
Aqua
Aura
CloudSat
240 sec
86 sec
43 sec
60 sec
30s
195 sec
98.5s
Trade: Equator crossing time (orbit inclination) for satellite longevity
MOWG or some other appropriate meeting
Fair warning for the science leads and an invitation for us all to think about how to go about maximizing the overall science we get out of the A-Train
Need to have Science weigh in on
possible changes in orbit.
Suggest: Science leads meet at the
next MOWG, Jun GSFC

9. A-Train Data Analysis Support
In the past, the Science of Terra and Aqua, Aura, CALIPSO & CloudSat ROSES solicitations have included/encouraged the utilization data from other satellite sensors in addition to the sensors specifically identified by the solicitation
A new Science of Terra and Aqua solicitation is to be release in ROSES-17 immanently, I expect this solicitation will follow the pattern of previous solicitations in this regard