Question: when did voyager 1 cross into interstellar space
[{'answer': 'August 25 , 2012', 'provenance': [{'wikipedia_id': '32781', 'title': 'Voyager 1', 'start_paragraph_id': 62, 'start_character': 175, 'end_paragraph_id': 62, 'end_character': 192, 'bleu_score': 1.0, 'section': 'Section::::Interstellar medium.\n'}]}, {'provenance': [{'wikipedia_id': '32781', 'title': 'Voyager 1', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 324, 'bleu_score': 0.866522238220184, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7440882464885438473}, 'section': 'Section::::Abstract.'}]}]