'As a fraction of your tax dollar today, what is the total cost of all spaceborne telescopes, planetary probes, the rovers on Mars, the International Space Station, the space shuttle, telescopes yet to orbit, and missions yet to fly?' Answer: one-half of one percent of each tax dollar. Half a penny. I'd prefer it were more: perhaps two cents on the dollar. Even during the storied Apollo era, peak NASA spending amounted to little more than four cents on the tax dollar.