Collins made the appeal following her arrival back on Earth at the end of the first mission since the Columbia disaster two and a half years ago and following a rocky start to the Discovery's just-ended 14-day mission.

"Some people say we should stop flying the shuttle because we had an accident. Frankly, we had two accidents," Collins said, referring to Columbia and the Challenger explosion in 1986.

"But we are people that believe in this mission and we are going to continue it," she told a news conference. "And I ask you to please support us -- it's very important to us."

The shuttles were "making life even better for all of us in this country and around the world by exploring space," she said, in an appeal to political doubters of the programme and the bereaved families of the Columbia astronauts.

"Space exploration is just a fantastic part of the human experience," said Collins.

While returning to the Earth's atmosphere was a mixed experience because that was the moment when the Columbia's seven-strong crew lost their lives on February 1, 2003, Collins called for understanding of the space mission.

"It's a very bittersweet day for us too as we remember the Columbia crew and we think about their families," she said of her former comrades whose pictures she kept on the Discovery flight deck.

But she said the Discovery crew, like their colleagues on Columbia, believed in space travel.

"We are continuing their mission and its very important to us that mission of discovery goes on," she implored.

Collins, still wearing her blue flight suit after undergoing medical examinations, said the greatest achievement of the mission was getting the space shuttle back into orbit, even if the journey was not trouble free.

"It's been two and a half years since Columbia. We worked very hard to do the right thing and make sure that we didn't miss anything. We did miss some things, but we're learning and we're going to go back and fix those things," she said.

Collins said the experience of being in space was very moving.

"It was a huge achievement, but just being in space, the human side of being in space is something I wish I could share with all of you," she said.

"At night we saw southern lights. We flew through the aurora and just beautiful moving lights with colours. We saw sunrises and sunsets," she said, describing the Discovery's overflight of five continents.

"The experience of just being a human in zero gravity is a fantastic experience," Collins said, adding she was having trouble readjusting to gravity back on Earth.

All rights reserved. copyright 2018 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.