The Solar System Origins Legacy Survey

A Cycle 26 Hubble Space Telescope Treasury Program.

Principal Investigator: Alex H. Parker, Southwest Research Institute.

Testing origin theories

The cold classical Kuiper Belt is likely a completely unique surviving remnant of the solar system's primordial planetesimal disk, and it has an extraordinarily high near-equal mass binary fraction. The binary rate, binary separation distribution, and binary color distribution within planetesimal populations are powerful tracers of planetesimal formation and evolution processes.

At the present time, the Kuiper Belt's binary rate, binary separation distribution, and binary color distribution can only be measured effectively by the Hubble Space Telescope. The Solar System Origins Legacy Survey (SSOLS) will advance our understanding of these properties by compiling new and archival Hubble Space Telescope observations of a large, well-defined "Treasury Sample" of 221 cold classical Kuiper Belt Objects.

The 206-orbit SSOLS program builds upon the legacy of OSSOS and CFEPS, the two largest well-characterized Kuiper Belt surveys ever conducted. This will be the first high-precision measurement of the Kuiper Belt's binary properties drawn from a well-characterized sample.

SSOLS will answer several key observational questions about this population, which together provide a coherent framework to robustly test current leading theories of planetesimal formation and the origin and evolution of the outer system's architecture.


Dr. Michele Bannister


Queen’s University Belfast

Dr. JJ Kavelaars



Dr. Keith Noll


NASA Goddard Space Flight Center

Dr. Alex H. Parker

Principal Investigator

Southwest Research Institute

Dr. Susan Benecchi


Planetary Science Institute

Dr. Will Grundy


Lowell Observatory

Dr. Simon Porter


Southwest Research Institute

Background image copyright Alex H. Parker, 2018.