Question: why did scientists use radio telescopes to bounce radar pulses off of venus
[{'answer': 'public relations value', 'provenance': [{'wikipedia_id': '264337', 'title': 'Radar astronomy', 'start_paragraph_id': 16, 'start_character': 281, 'end_paragraph_id': 16, 'end_character': 303, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'answer': 'demonstration to funding agencies', 'provenance': [{'wikipedia_id': '264337', 'title': 'Radar astronomy', 'start_paragraph_id': 16, 'start_character': 326, 'end_paragraph_id': 16, 'end_character': 359, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'answer': 'to measure the size of the astronomical unit , which was needed for the nascent field of interplanetary spacecraft'}, {'provenance': [{'wikipedia_id': '264337', 'title': 'Radar astronomy', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 791, 'bleu_score': 0.965400604802336, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6221201365772363959}, 'section': 'Section::::History.\n'}]}]