Nasa astronauts who are stranded in space until next year have stated that they did not feel let down by Boeing, but acknowledged experiencing "tough times", according to the German Press Agency (dpa). Boeing's inaugural astronaut mission concluded earlier this month with its Starliner capsule returning to Earth, while test pilots Barry 'Butch' Wilmore and Sunita Williams remained in space. Wilmore commented, "We discovered certain aspects that we were not entirely comfortable with, which led us to opt out of returning in the Starliner when alternative options were available." Nasa has confirmed that the duo will instead return on a SpaceX craft in February, extending their initial eight-day mission to over eight months. During a press conference on Friday from the International Space Station, Wilmore remarked, "It has been quite a journey over the past three months. We have been involved from the start, through all the processes of evaluating our spacecraft, Calypso." He added, "It was challenging at times. There were tough moments throughout." As the commander and pilot of their spacecraft, Wilmore admitted, "You certainly don't want to see it depart without you, but that's the situation we found ourselves in." When asked if he felt let down by Boeing after Starliner returned to Earth without its crew, Wilmore replied, "Let down? Absolutely not." He continued, "It never crossed my mind. I don't think Suni felt that way either, until you brought it up." Wilmore also mentioned that Boeing was "on board" with making the necessary "changes" following the company's Starliner capsule returning to Earth without its crew. The astronaut explained at the press conference, "Clearly, when issues arise, as we have encountered, there are changes that need to be implemented." He added, "Boeing is in agreement with that. We are all in agreement with that." Wilmore further elaborated, "When you push the boundaries and undertake tasks with spacecraft that have never been done before, such as with Starliner, you are bound to encounter some challenges." He concluded, "In this instance, we identified certain aspects that we were not comfortable with, which led us to choose other options for our return." Wilmore highlighted that in the past, there were often no alternative options available. He expressed gratitude, "We were fortunate to have the Space Station and the option to stay and return via a different route."