Angela Roberts Reeder, right, jokes with colleagues at the Smithsonian National Museum of Natural History on their first day back to work. (Bonnie Jo Mount/The Washington Post)

For the first time in a month, the alarm went off at 5:30 a.m., and Angela Roberts Reeder rose to go to work.

She dressed in the pre-dawn gloom, boiled water for tea, fed the cats so their cries wouldn’t wake her still-sleeping husband. She checked her email — 250 unread messages — and groaned. She put on earrings and applied a smear of lipstick; a little something extra for a day when she might need it.

“Here we go,” she said, steeling herself for the commute that for so long had been routine: a 45-minute drive from her Baltimore home to the Greenbelt Metro station, another 45 minutes on the Green Line to downtown D.C., a walk along Constitution Avenue and up the steps of the National Museum of Natural History, where Roberts Reeder is an exhibits writer and editor.

The 25 days she’d been furloughed had been listless and lonely, full of frustration about the news and worry about making her mortgage payment. Now she and 800,000 fellow federal employees were finally headed back to their jobs.

But what would they find when they arrived?

At the Natural History Museum, staff showed up Monday to confront bloated trash cans and blown deadlines. A dead cockroach on an office floor. Exhibits that would need to be revised, meetings that would need to be rescheduled, experiments that would need to be replanned.

They returned to their offices demoralized yet determined, relieved to be back at work and anxious about what would happen when this stopgap spending measure runs out.

“It’ll be a relief to get a paycheck,” Roberts Reeder said. “But in three weeks, it might all happen again.”

It had been surprisingly hard, not being able to do her job. Not being able to talk with her colleagues or stand in the corner of an exhibit and watch visitors respond to the words she had written. Those things are what drew her to the Smithsonian in the first place, what convinced her to keep commuting an hour and a half each way from the city where her husband works, the only place where the couple could afford a house of their own.

During the shutdown, Roberts Reeder said, “I really struggled with feeling like the work we do was devalued.”

But as she approached the museum Monday, she smiled at its impressive granite facade.

“It’s still kind of. . . ” She took a breath. “It’s still kind of amazing that I work here.”

About 30 percent of the museum’s staff kept working after the Smithsonian ran out of funds on Jan. 2 (10 days after the rest of the federal government). Many were “excepted” from furlough for work related to the museum’s new fossil hall, which is slated to open June 8. Others were “trust” employees, whose positions are paid for by endowments.

Conservator Catherine Hawks and two others were retained to ensure the security of the museum’s entire collection of 145 million objects. Every day, their footsteps had echoed in the eerily empty halls as they looked in on colossal freezers, locked labs and cavernous closets to be sure no harm came to any prized artifacts.

On Monday, the building slowly came back to life. Lights switched on. Displays were reanimated. Custodial staff buffed the floors for the first time in weeks.

Geologist Cari Corrigan, who curates the nation’s Antarctic meteorite collection, gathered up the protective plastic sheets she’d laid out over her lab. Checking her email, she discovered that a crate of 250 space rocks would be arriving the next day; she would have just a few weeks to analyze and classify all of them.

The lights in her lab flickered. Corrigan sighed.

“You come back after a month and you have dead bugs on the floor and your lights don’t work and there’s so much to do.”

A few floors below, biological anthropologist Sabrina Sholts walked through the museum’s empty “Outbreak” exhibit, for which she is curator. She ran her hand over explanatory panels, experimentally pressing buttons on the video displays, eager to make certain that everything was ready for visitors when the museum reopened to the public on Tuesday.

She paused in front of a display about the 2014 Ebola outbreak in West Africa and tapped on text exploring what animals might harbor the deadly virus.

“I think maybe we want to update that,” she said. Days earlier, researchers announced they had detected Ebola in a bat in Liberia.

“It’s a shame we had to miss these hundreds or thousands of visitors who could be learning more about these things they hear about in the news,” she said.

The time out of work had been agonizing for her, too, Sholts said. Instead of writing a journal article on genomics and analyzing lab rat mandibles for evidence of damage from environmental toxins, she spent her days compulsively refreshing the Web pages of three different news sites, hoping one would report a breakthrough.

On Thursday, when the Senate failed to pass either of two spending bills to reopen the government, Sholts hit “an emotional breaking point.”

“It came down on me how unfair it was for those of us who just want to do our jobs, who love our jobs,” she said. “I am very relieved to be back . . . but even that’s kind of weird. You shouldn’t feel relieved to get to go to your job.”

Walking into her office, Roberts Reeder was delighted to find that an amaryllis plant she’d been given before the holidays had flourished during the month of neglect. She plugged in her computer, put a new liner in her trash can and threw out the December calendar that was still pinned above her desk.

“Welcome back,” said Siobhan Starrs, who had been excepted for her work as project manager of the new fossil hall. “You okay?”

Roberts Reeder shrugged. “Yeah.”

“You sure?”

“Yeah.”

“I missed you,” Starrs said.

“I missed you too,” Roberts Reeder replied. “It’s good to be back.”