For $150 billion, the National Aeronautics and Space Administration could have sent astronauts back to the Moon. The Obama administration judged that too expensive, and in September, Congress agreed to cancel the program.

For a fraction of that  less than $200 million, along with about $250 million for a rocket  NASA engineers at the Johnson Space Center in Houston say they can safely send a humanoid robot to the Moon. And they say they could accomplish that in a thousand days.

The idea, known as Project M, is almost a guerrilla effort within NASA, cooked up a year ago by Stephen J. Altemus, the chief engineer at Johnson. He tapped into discretionary money, pulled in engineers to work on it part time, and horse-traded with companies and other NASA units to undertake preliminary planning and tests. “We’re doing impossible things with really very little, if any, money whatsoever,” Mr. Altemus said.

A humanoid dextrous robot  at least the top half  already exists: Robonaut 2, developed by NASA and General Motors, is packed on the shuttle Discovery, scheduled for liftoff on Wednesday.