NASA officials warned that the project, which costs $800 million, would be difficult to carry out.

NASA officials said the training would be carried out in several stages.

NASA officials said he signed it out in 1965, for a school presentation.

NASA officials said the report was not meant for public consumption.

NASA officials said it would be two or three weeks before they got a report on what went wrong.

NASA officials said the mission would cost about $205 million.

NASA officials past and present say it is not that easy.

NASA officials hinted two months ago that such a study might take place.

NASA officials said the partners would find ways to support the plans, as in the past.

NASA officials have already approved such a mission, should it be necessary.