Agencies within the Executive Office of the President:
In my experience the term 'executive agency' is for certain bureaus in the British government. Since NASA is a part of the US government it would not be an executive agency under this definition. If you mean, is it an agency falling under the US Executive Branch (under the President) then yes, it falls under the President.
the govners office
The executive branch of the US government is the president.
The purpose of the executive branch of the US government is to enforce laws.
the president
The president heads the executive branch of the US federal government.
The Executive Branch. United States Customs and Border Protection is an agency of the Department of Homeland Security.
The President is chief executive of the Executive Branch of the US government.
The governor's office
The President of the United States heads the executive branch of the US government.
executive branch
The IRS is an agency within the United States Department of the Treasury. It is part of the executive branch of the US government.