Complex sentence: A 2016 peer reviewed paper by a team of NASA scientists gave evidence of a RF resonant cavity generating an anomalous thrust, but not all sources of error could be completely ruled out and the more experimentation is needed to confirm the result.
Split into simpler sentences: A 2016 peer reviewed paper by a team of NASA scientists gave evidence that a RF resonant cavity generated an anomalous thrust that could not otherwise be accounted for. Not all sources of error could be completely ruled out however, and the more experimentation is needed to confirm the result.