Question: when was the first satellite put in space
[{'answer': 'October 4 , 1957', 'provenance': [{'wikipedia_id': '61536', 'title': 'Explorer 1', 'start_paragraph_id': 5, 'start_character': 457, 'end_paragraph_id': 5, 'end_character': 473, 'bleu_score': 1.0, 'section': 'Section::::Background.\n'}]}, {'provenance': [{'wikipedia_id': '61536', 'title': 'Explorer 1', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 579, 'bleu_score': 0.979054689945215, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2960547012670519385}, 'section': 'Section::::Background.\n'}]}]