Question: when was the first us space shuttle launched
[{'answer': '12 April 1981', 'provenance': [{'wikipedia_id': '177543', 'title': 'STS-1', 'start_paragraph_id': 1, 'start_character': 148, 'end_paragraph_id': 1, 'end_character': 161, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '177543', 'title': 'STS-1', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 624, 'bleu_score': 0.85351166775661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17864800375215492944}, 'section': 'Section::::Abstract.'}]}]