Ousted prime minister Thaksin Shinawatra has already secured an entry visa to the US and the visa has nothing to do with Nasa's request to use U-tapao naval airbase, his legal adviser said.
Noppadon Pattama said the US granted an entry visa to Thaksin a few months ago and he is now able to travel to the US.
Mr Noppadon said he previously did not want to make known the granting of the US visa to Thaksin because it could have been exploited by the Democrat Party for political game-playing against the government.
Mr Noppadon rejected accusations by the Democrat Party that the Yingluck Shinawatra government tried to seek a US visa for Thaksin, Ms Yingluck's elder brother, in exchange for allowing the US to use U-tapao airport. The government denies the claim.
Nasa scrapped the project to research weather conditions over Southeast Asia, which would have used U-tapao in Rayong, after the cabinet failed to approve the project by the June 26 deadline set by the US space agency.
Mr Noppadon also commented on the Constitution Court's hearing on the legality of the government-sponsored charter amendment bill.
He said he hoped the court's decision would be based on a correct and sound judgement so democracy could continue to function.