The National Symphony Orchestra opened its 80th anniversary gala concert at the Kennedy Center Concert Hall on Sunday night with a double-barreled announcement from the center’s chairman, David M. Rubenstein. Christoph Eschenbach, the internationally renowned conductor and music director of the Kennedy Center, will extend his contract for two years, through the 2014-15 season. And the concert hall will, at long last, be getting a new organ.

The new organ comes courtesy of Rubenstein, who is donating the instrument — valued at about $2 million — as well as the cost of installation, which is slated to take place next summer. Built by the Canadian firm Casavant Frères, the new 5,000-pipe organ will replace the Filene organ, which was built by Aeolian-Skinner.

Although installed in 1972 and relatively young in organ terms, the 4,000-pipe Filene organ was problematic from the start — Aeolian-Skinner folded as the instrument was being put in — and has become so erratic, in part due to flooding and other wear and tear sustained during the renovation of the concert hall in 1997, that it has been virtually unusable.

In 2008, Lynn Dobson, an independent organ builder whom the Kennedy Center called in to assess it, said the instrument was not worth saving.

The new organ will retain 61 pipes from the old instrument in a special “Filene stop.”

Eschenbach’s contract extension comes after only one season. That first season was generally successful, certainly from the point of view of the orchestra’s musicians, who are in full honeymoon mode about their conductor.

Eschenbach has given a couple of free chamber concerts with individual musicians on the Millennium Stage. It’s hard to say what larger effect he has had on the Kennedy Center’s programming, and he has not necessarily raised the orchestra’s national or international profile yet (though an international tour is said to be in the works). Still, extending the contract offers more stability to an orchestra that has gone through a long period of uncertainty about its artistic leadership, and offers a vote of confidence to a conductor whose last tenure in Philadelphia was far less harmonious.