  Recently, we witnessed how the synergy of small satellite technology and
solar sailing propulsion enables new missions. Together, small satellites with
lightweight instruments and solar sails offer affordable access to deep regions
of the solar system, also making it possible to realize hard-to-reach
trajectories that are not constrained to the ecliptic plane. Combining these
two technologies can drastically reduce travel times within the solar system,
while delivering robust science. With solar sailing propulsion capable of
reaching the velocities of ~5-10 AU/yr, missions using a rideshare launch may
reach the Jovian system in two years, Saturn in three. The same technologies
could allow reaching solar polar orbits in less than two years. Fast,
cost-effective, and maneuverable sailcraft that may travel outside the ecliptic
plane open new opportunities for affordable solar system exploration, with
great promise for heliophysics, planetary science, and astrophysics. Such
missions could be modularized to reach different destinations with different
sets of instruments. Benefiting from this progress, we present the "Sundiver"
concept, offering novel possibilities for the science community. We discuss
some of the key technologies, the current design of the Sundiver sailcraft
vehicle and innovative instruments, along with unique science opportunities
that these technologies enable, especially as this exploration paradigm
evolves. We formulate policy recommendations to allow national space agencies,
industry, and other stakeholders to establish a strong scientific,
programmatic, and commercial focus, enrich and deepen the space enterprise and
broaden its advocacy base by including the Sundiver paradigm as a part of
broader space exploration efforts.
