Daniel Terdiman/CNET

With Congress' failure to agree on a federal budget for 2014 on Monday night, the US government began the process of shutting down, affecting many who work in science.

The first federal government shutdown since 1996 is expected to lead to the furlough of 800,000 federal employees in a wide range of services and departments, including federal science research programs such as space exploration.

"NASA will shut down almost entirely," President Obama said Monday in a statement, meaning unpaid time off for the majority of the agency's 18,000 employees. However, he said that Mission Control employees in Houston would remain on the job to support astronauts orbiting the Earth in the space station.

Other agencies conducting research programs expected to be affected include the Department of Energy and the National Science Foundation, which will allow work to continue on projects supported by grants but won't be making any new payments.

Most of the Environmental Protection Agency's 17,000 employees will also be staying home, EPA chief Gina McCarthy said last week, according to The Hill. However, a few EPA officials would remain on the job "to keep the lights on and to respond in the event of a significant emergency," she said.

More than two-thirds of staff at the Centers for Disease Control and Prevention will be furloughed, according to a contingency staffing plan posted to the Department of Health and Human Services' Web site. The shutdown means no funding to investigate outbreaks or to support the agency's annual flu vaccination program.

Meanwhile, many employees essential to the nation's safety and defense will keep working. The US military's 1.4 million active-duty personnel will to stay at their posts, but their paychecks will be delayed, despite a House bill that would have ensured that troops would continue to be paid on time in the event of a government shutdown.

Also tasked with protecting the nation's security, employees of the Department of Homeland Security are exempt from the shutdown, as are most employees of the Customs and Border Protection and the Transportation and Security Administration, which will continue to screen airline passengers. The FAA said its air traffic controllers will stay on the job to prevent disruption to air travel.

The National Weather Service, meanwhile, will continue monitoring atmospheric conditions and issuing forecasts. Similarly, employees of the National Hurricane Center and National Oceanic and Atmospheric Administration will stay on the job. The US Geological Survey will temporarily cease operations.

However, AsteroidWatch, the Jet Propulsion Laboratory's effort to detect and track asteroids and comets that could pose a threat to Earth, said it will stop tweeting about potential threats. "In the event of government shutdown, we will not be posting or responding from this account. We sincerely hope to resume tweets soon," the office said in a tweet Monday.