Opinion | How Activists Brought Apollo Back to Earth

Other grass-roots movements took up the cause. Environmentalists blamed Apollo launches for fouling Cape Canaveral, and the space race for distracting Americans from a mounting pollution problem. They also lobbied Congress to force NASA to be more environmentally responsible. Feminists, in coordination with the National Organization for Women, joined letter-writing campaigns, picketed outside NASA’s Washington headquarters and filed lawsuits to change NASA’s sexist hiring practices and its all-male astronaut corps.

Congress and NASA had been able to largely ignore these grass-roots complaints because the nation as a whole was behind the space effort. But after Neil Armstrong and Buzz Aldrin stepped on the lunar surface, winning the race, support for space exploration began to wither while public pressure on Congress grew to reallocate the billions devoted to space. Soon politicians were echoing the activists.

In a speech just before the Apollo 11 launch, Senator Ted Kennedy — whose brother, President John Kennedy, vowed to put a man on the moon before the 1960s ended — argued that “a substantial portion of the space budget can be diverted to more pressing problems here at home.” Congress soon agreed and by 1974 slashed the space agency’s budget by more than 20 percent.

To stem decline in its popularity and bottom line, NASA began to address some of those grass-roots concerns. In 1971 the space agency scrapped much of its research for the Vietnam War. The following year it launched what would eventually become known as Landsat, the first of many satellites to gather data used by environmental scientists to track land, air and water pollution. And the year after, NASA took the first steps to opening up the astronaut corps to women.

The space agency also created its own Urban Systems Project Office in 1972 to retool space technologies to aid poor inner-city residents. In one effort, which was only partly successful, NASA engineers teamed up with the Department of Housing and Urban Development to repurpose energy-efficient heating and cooling systems, originally used in the Apollo space capsule, for use in low-income housing projects.

Today, the space race has become a mostly commercial enterprise pursued by billionaire entrepreneurs like Elon Musk, Jeff Bezos and Richard Branson. “We want a new space race,” Mr. Musk said, but one that pits private companies rather than nations against one another.

Such privatization has succeeded wonderfully on an economic level. Mr. Musk built his Falcon Heavy rocket for one-tenth the price of the Saturn V that sent Armstrong, Aldrin and Michael Collins to the moon. Americans should encourage these free-market efforts but also understand their potential pitfalls.