NASA logo

The Outer Planets Assessment Group (OPAG) was established by NASA in late 2004 to identify scientific priorities and pathways for exploration in the outer solar system. The group consists of a 15-person steering committee, which actively solicits input from the scientific community and reports its findings to NASA Headquarters. OPAG provides input to NASA but does not make recommendations.

OPAG Charter

OPAG is NASA's community-based forum designed to provide science input for planning and prioritizing outer planet exploration activities for the next several decades. It is chartered by NASA's Solar System Exploration Division and reports its findings at meetings of the Solar System Exploration Sub-Committee of the NASA Space Science Advisory Committee. Open to all interested scientists, OPAG regularly evaluates outer solar system exploration goals, objectives, investigations and required measurements on the basis of the widest possible community outreach.

Upcoming Meeting

OPAG Summer 2017 Meeting: 

Please join us September 6–7, 2017 in La Jolla, CA, at the Samuel H. Scripps Auditorium, next to the largest ocean in the inner Solar System.

Recent Meetings

February 22–23, 2017
Hosted by Georgia Tech
The Georgian Terrace

August 11–12, 2016
Flagstaff, Arizona
There will also be a ROW meeting on August 10, in Flagstaff.

February 1–2, 2016
Southwest Research Institute (SWRI)
San Antonio, Texas

August 24–26, 2015
Laurel, MD

March 18, 2015 LPSC OPAG Townhall Presentations with notes

Europa Lander Instrument PEA

Special OPAG Steering Committee Finding, May 26, 2017

NASA released "Community Announcement Regarding Europa Lander Instrument Investigation Program Element Appendix” on May 17, 2017 (see  This announcement included a surprising statement regarding participation by JPL: "…the following organizations will be prohibited from submitting proposals in response to the PEA: the Jet Propulsion Laboratory (JPL), Cornell Technical Services (CTS), and Arctic Slope Regional Corporation.  These organizations will provide substantial support to the development and execution of the PEA.  In particular, JPL personnel will support the development of the AO and documents in the Program Library, assess the accommodation of proposed instrument investigations, provide technical support to teams during Step 2, and participate in site visits during the Step-2 evaluation.”  The OPAG steering committee is concerned about the potential exclusion of JPL scientists and instrument technology experts who have spent decades preparing for a life-detection mission such as Europa Lander.  We urge NASA to proceed in a way that does not increase risk to Europa Lander science by excluding key capabilities.  We note that NASA has funded much highly relevant work at JPL via R&A programs and the Astrobiology Institute, and instrument technology development via MatISSE, PICASSO, COLDtech, and other programs.  Excluding the knowledge gained from such efforts would be counterproductive.


THE OPAG Steering Committee urges NASA to proceed with Europa Lander instrument and science team selections in a way that results in the best possible science return. 

OPAG Science Goals Document 2015

Draft for Community Comment

Scientific Goals for Exploration of the Outer Solar System

Outer solar system exploration motivation

Europa Studies

2013 Europa Clipper Update
Robert Pappalardo, Jet Propulsion Laboratory, California Institute of Technology
Brain Cooke, Applied Physics Laboratory, Johns Hopkins University

"Science Potential from a Europa Lander" in Astrobiology
Read the definitive, peer-reviewed version of the Science Definition Team's report on "Science Potential from a Europa Lander" in the journal Astrobiology.

Older Europa Mission Studies

Europa Lander Science Definition Team (SDT)  

Indication of Interest