  Solitary wave structures observed by the Ulysses spacecraft in the solar wind
were analyzed using both inverse scattering theory as well as direct numerical
integration of the derivative nonlinear Schr\"odinger (DNLS) equation. Several
of these structures were found to be consistent with soliton solutions of the
DNLS equation. Such solitary structures have been commonly observed in the
space plasma environment and may, in fact, be long-lived solitons. While the
generation of these solitons may be due to an instability mechanism, e.g., the
mirror instability, they may be observable far from the source region due to
their coherent nature.
