Correction: An earlier version of the article incorrectly said that the Energy Department has furloughed 13,814 employees. The department plans to furlough many of its 13,814 employees if the shutdown is not resolved “in the near term,” according to a spokesman, but it has multi-year funding and has not yet told employees to stay home. This version has been corrected.

Yes, the federal government is closed. Beside national parks, here are five other things that have shut down along with it, including NASA. (The Washington Post)

Much of the government’s sprawling scientific and technological machinery has been turned off, and researchers and engineers fear that a prolonged shutdown could imperil their projects and create lasting harm to U.S. innovation.

One immediate impact: Sick people hoping to join clinical trials at the National Institutes of Health are being turned away. Nearly three-fourths of NIH employees have been furloughed. Patients already enrolled in NIH clinical trials will continue to receive care.

If the shutdown persists, it could affect about 200 people per week who, under normal circumstances, would be admitted to new trials, said John T. Burklow, an NIH spokesman. On average, about 30 of those new patients would be children, and about 10 would be children with cancer, he said.

“Everyone feels absolutely awful. It’s antithetical to our mission and why we’re all here. Even if it’s a delay,” Burklow said. “If you have a child who needs help, even if you’re told, ‘Well, we can’t help you today,’ it just creates anxiety and frustration, I’m sure.”

After The Wall Street Journal reported on the pause in new admissions to clinical trials, House Republicans on Wednesday introduced legislation, named the Research For Lifesaving Cures Act, that would restore NIH funding to pre-shutdown levels. Democrats have held firm to their position that the entire government must be reopened.

Here's what some agencies have said about their specific plans in case of a government shutdown.

Skeleton crews are monitoring NIH laboratory experiments and caring for research animals.

“They’ll make sure that the cells in the Petri dishes don’t die,” said L. Michelle Bennett, deputy scientific director for the National Heart, Lung, and Blood Institute. Like most people at the NIH campus, she has been furloughed. “It’s kind of weird. I think we were hoping it wouldn’t happen, but we’ve been preparing.”

Agencies that funnel billions of dollars in research grants are now closed for the most part. Web sites that scientists and academics rely on have gone dark. Almost everyone at the National Science Foundation, a major source of federal grants, has been furloughed.

The Energy Department plans to furlough many of its 13,814 employees if the shutdown is not resolved “in the near term.” The National Nuclear Security Administration, part of the Energy Department, will continue to monitor the safety of the atomic arsenal.

NASA has furloughed all but 549 of its more than 18,000 employees. The astronauts on the international space station aren’t getting sent home, of course, and Mission Control in Houston remains staffed.

But certain NASA activities are governed not by bureaucrats but by astronomical realities. NASA has a new robotic Mars probe, called MAVEN, that is supposed to launch Nov. 18, and it is being processed at NASA’s Kennedy Space Center. If, however, it misses its launch window, the spacecraft would have to be sidelined for more than two years, until Earth and Mars once again come into the proper orbital alignment in 2016.

Federal workers, meanwhile, will maintain long-distance support for scientists stationed in Antarctica, which is emerging from its dark and brutal winter. On the social-media site Reddit, one anonymous government contractor in Antarctica said that a supply ship is still on course to bring food and fuel, but that if the shutdown continues the scientific stations will have to close down, with only skeleton crews on duty.

Most of the federal R&D budget goes to outside (“extramural”) researchers, who for the time being can keep wearing their lab coats and working on their projects. There could be a ripple effect, though, as federal employees who process grant applications remain at home, scientists said.

“If people have funding, they can continue, yes. But anybody caught between grants or dependent on a new grant, or even the extension of an existing grant, they’re all directly impacted,” said Stephen Merrill, director of science, technology and economic policy at the National Research Council, a private nonprofit that remains open for business.

Merrill had been in the process of applying for a government grant, only to find that the granting agency’s Web site wasn’t working.

“I think it’s bad. Is it catastrophic? Not unless it goes on for a long time,” Merrill said.

The American Association for the Advancement of Science released a statement Tuesday lamenting the shutdown. On Wednesday, Marcia McNutt, who served as head of the U.S. Geological Survey during President Obama’s first term and is now the editor in chief of the AAAS journal Science, published an editorial stating that “the U.S. research system is greatly compromised” without contributions from government science laboratories.

During the shutdown, she wrote, scientific agencies “will no longer be able to track flu outbreaks, update real-time information on water quality and quantity, improve weather forecasts, develop advanced defense systems to keep us safe, and serve many more immediate needs.”

Matthew Hourihan, an AAAS spokesman, criticized lawmakers for trimming the discretionary part of the federal budget rather than focusing on mandatory spending and taxes.

“For the most part, they’ve been attacking discretionary spending, which is where most science lives,” Hourihan said in an interview.

Since the end of the space race, federal R&D spending has slowly eroded as a percentage of the U.S. economy, he said. The AAAS said that the government is committing less than 1 percent of the gross domestic product to research and development, the lowest level in four decades.

Physical sciences and engineering have been particularly hard-hit, said Merrill of the NRC. “We’ve been shortchanging it now for a generation,” he said. And sequestration has hit the R&D world hard, he said.

Roughly half of the government’s R&D budget goes to the military, and another quarter goes to NIH, Hourihan said. The rest goes to the Energy Department, NASA, the National Science Foundation, the Agriculture Department and other agencies.