(MSN) - The government reopened its doors Thursday after a battle-weary Congress approved a bipartisan measure to end a 16-day partial shutdown and avert the possibility of an economy-jarring default on U.S. obligations.

Early Thursday, President Barack Obama signed the measure, which the House and Senate passed late Wednesday, ending a brawl with Republicans who tried to use the must-pass legislation to mount a last-ditch effort to derail the president's landmark health care law and demand concessions on the budget.

The White House directed all agencies to reopen promptly and in an orderly fashion. Furloughed federal employees across the country are expected to return to work Thursday.

The impasse had shuttered national parks and monuments, and mostly closed down NASA, the Environmental Protection Agency and the Interior Department. Critical functions of government went on as usual and most federal employees won't see their paychecks delayed, but the closure and potential default weighed on the economy and spooked the financial markets.

There were signs early Thursday that the federal government was slowly coming back to life. "We're back from the #shutdown!" the Smithsonian Institution crowed on Twitter, announcing that museums would reopen Thursday and the National Zoo in Washington on Friday.

Standard & Poor's estimated the shutdown has taken $24 billion out of the economy, and the Fitch credit rating agency warned Tuesday that it was reviewing its AAA rating on U.S. government debt for a possible downgrade.