COSI is a balloon-borne soft gamma-ray (0.2-10 MeV) telescope designed to study astrophysical sources of nuclear line emission and gamma-ray polarization. NASA successfully launched this super pressure balloon (SPB) from Wanaka Airport, New Zealand, at 11:35 a.m. Tuesday, May 17, (7:35 p.m. EDT Monday, May 16) on a potentially record-breaking, around-the-world test flight.

See the video in Youtube:

Live trajectory:

A post in the NASA-Wallops-Flight-Facility webpage:

COSI official web-page: