At today's final landing of the space shuttle, we had the rare opportunity to witness history. We turned the page on a remarkable era and began the next chapter in our nation's extraordinary story of exploration.

The brave astronauts of STS-135 are emblematic of the shuttle program. Skilled professionals from diverse backgrounds who propelled America to continued leadership in space with the shuttle's many successes. It is my great honour today to welcome them home.

I salute them and all of the men and women who have flown shuttle missions since the very first launch on April 12, 1981.

The shuttle program brought our nation many firsts. Many proud moments, some of which I was privileged to experience myself as a shuttle commander. I was proud to be part of the shuttle program and will carry those experiences with me for the rest of my life.

As we move forward, we stand on the shoulders of these astronauts and the thousands of people who supported them on the ground – as well as those who cheered their triumphs and mourned their tragedies.

This final shuttle flight marks the end of an era, but today, we recommit ourselves to continuing human spaceflight and taking the necessary and difficult steps to ensure America's leadership in human spaceflight for years to come.

I want to send American astronauts where we've never been before by focusing our resources on exploration and innovation, while leveraging private sector support to take Americans to the International Space Station in low Earth orbit.

With the bold path President Obama and Congress have set us on, we will continue the grand tradition of exploration.

Children who dream of being astronauts today may not fly on the space shuttle ... but, one day, they may walk on Mars. The future belongs to us. And just like those who came before us, we have an obligation to set an ambitious course and take an inspired nation along for the journey.

I'm ready to get on with the next big challenge.

The future is bright for human spaceflight and for NASA. American ingenuity is alive and well. And it will fire up our economy and help us win the future, but only if we dream big and imagine endless possibilities. That future begins today.