July 21, 2011  -- When Chris Ferguson, commander of the space shuttle Atlantis, left the International Space Station for the last time, he left behind a symbolic gift. It was a small U.S. flag that had flown in space 30 years before, on the very first shuttle flight in 1981, and it is to be retrieved by the next astronauts to be launched from U.S. soil -- something that may be several years away.

The astronauts of Atlantis are ending the space shuttle era just as other countries ramp up their own space programs. If U.S. astronauts are going to fly over the next few years, they will have to hitch rides on Russian Soyuz spacecraft for $56 million each. If a space explorer is going to plant a new flag on the moon, it may very well be Chinese.

And if that is bittersweet for the astronauts, it gets some leaders in Washington angry.

"The United States needs a reality check on China," said Rep. Frank Wolf, a Virginia Republican whose appropriations subcommittee oversees NASA. "China also is aggressively spying on our country, including stealing the very technology needed for a space program. We cannot cede the space frontier to the Chinese."

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China has a smaller, slower-moving space program than the United States, but one that appears to be methodically planned. It didn't launch its first astronaut until 2003, but Chinese leaders say it will start assembling a small space station this year, launch a rover to the moon next year, and land astronauts on the moon in the 2020s.

"As countries like China attempt to challenge U.S. leadership in space, we need a similar sense of mission to guide NASA going forward," Rep. Wolf said.

Some politicians and space people see the shuttles' retirement as a threat to U.S. security, technological leadership, and pride as well. A lot of people, including some of the best-known figures in U.S. space history, don't like the idea of depending on other countries.

"What if something goes wrong with the Soyuz?" asked John Glenn, the first U.S. astronaut to orbit the Earth in 1962. Glenn turned 90 this week. "If we have a hiccup on the Soyuz right now, we don't have a manned program."

Sen. Kay Bailey Hutchison, R-Texas, said, "The administration's delays put current and future American jobs and industries at risk, and hand over to competing nations a golden opportunity to take the global lead in technology."

Rep. Wolf said he hopes the Chinese threat, in particular, prompts America to reinvigorate its space effort, even in tough budget times. "We need to make cuts, but we need to make smart cuts," he said in an interview with ABC News. "If we cut NASA, if we cut cancer research, we're eating our seed corn."

Kick in the Pants?

But would a Chinese triumph in space -- a space station or a lunar landing -- get the U.S. program moving again? Not very likely, say some people who have watched NASA closely.

"I don't think it is automatic that we would race back to the moon if China went," said Mark Carreau, a veteran space reporter who covered Atlantis' final flight for Aviation Week and Space Technology. "I think it depends on why they go. My own guess is we will go together as a team with a number of nations, and the U.S. and China might be partners."

Joan Johnson-Freese, a professor at the U.S. Naval War College who watches space policy, said she is concerned about the Chinese efforts, but doubts they will push America to action.

"We need to start moving soon. The geostrategic implications of space regarding leadership are to important to ignore. Unfortunately, that's a hard economic sell right now," she said in an email to ABC News. "Americans are out of work. They see human spaceflight as a nice thing to do, but expendable."

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But U.S.-Chinese relations run hot and cold, and China's intentions in space, like America's, are military as well as scientific. In 2007, the Chinese used an old weather satellite for target practice for an anti-satellite missile. The result: Thousands of pieces of debris were left in the Earth's orbit, a potential risk to the space station and other vehicles. The United States protested, but the damage was already done.

Marcia Smith, a longtime space policy analyst at the Congressional Research Service who now consults and runs her own website, SpacePolicyOnline.com, said the Chinese may be talking bigger than they're actually doing.

"There are space enthusiasts who have been hoping for years that the Chinese would launch America into a new space race," she said, "but it's just not happening."

Astronaut Ferguson said in a preflight interview with ABC News, "It is going to take an Apollo-like commitment to really bring Mars into focus. Do I think it is going to be a unilateral commitment by the USA? No. I think it is going to be a global commitment by space-faring nations to pool their resources, realizing this is something beyond the capability of any one country."

ABC News' Gina Sunseri contributed to this report. Additional reporting by the Associated Press.