Lockheed Martin machinists at Stennis Space Center returned to work Wednesday after going on strike picketing the north and south gates.

The machinists, who are members of the International Association of Machinist and Aerospace Workers, began the strike Friday at 12:01 a.m. in protest of Lockheed Martin changing the workers’ retirement plan from a pension through the IAM to a 401K through Lockheed Martin.

Lockheed Martin released a statement Tuesday stating, “We’re pleased that the union members voted to accept the company’s last, best and final offer, and will return to work by Wednesday, May 21. The ratification of this new, three-year contract is excellent news for our company, the represented employees, their communities and the customer.”

IAM Spokesperson Frank Larkin said Lockheed Martin’s move to a 401K plan in lieu of their long standing pension plan is what promoted machinists to strike.

Lockheed Martin’s contract at Stennis Space Center is for three years, but Larkin said there is no guarantee Lockheed will be the contractor after that time.

“With a new contract is a new opportunity to re-instate the pension plan,” Larkin said.

Until Lockheed Martin’s contract expires, the machinists will be enrolled in a 401K through the company and not the pension plan with IAM.