In 1984, Charles D. Walker became the first non-government astronaut to fly, with his employer McDonnell Douglas paying $40,000 for his flight. NASA was also eager to prove its capability to Congressional sponsors. During the 1970s, Shuttle prime contractor Rockwell International studied a $200-300 million removable cabin that could fit into the Shuttles cargo bay. The cabin could carry up to 74 passengers into orbit for up to three days. Space Habitation Design Associates proposed, in 1983, a cabin for 72 passengers in the bay. Passengers were located in six sections, each with windows and its own loading ramp, and with seats in different configurations for launch and landing. Another proposal was based on the Spacelab habitation modules, which provided 32 seats in the payload bay in addition to those in the cockpit area. A 1985 presentation to the National Space Society stated that although flying tourists in the cabin would cost $1 to 1.5 million per passenger without government subsidy, within 15 years 30,000 people a year would pay $25,000 each to fly in space on new spacecraft. The presentation also forecast flights to lunar orbit within 30 years and visits to the lunar surface within 50 years.. How many fewer dollars would people pay in 15 years to travel to space over the initial cost per person at the smallest estimate?