Complex sentence: On 15 December 2016, "Stargazer" launched CYGNSS on behalf of NASA on its second attempt; the first was scrubbed due issues with the hydraulic system responsible for separating the Pegasus rocket from the launch aircraft.
Split into simpler sentences: On 15 December 2016, "Stargazer" launched CYGNSS on behalf of NASA on its second attempt. The first was scrubbed due issues with the hydraulic system responsible for separating the Pegasus rocket from the launch aircraft.