In a letter sent Thursday to the NASA administrator, Maj.
Mr. Perez's reply, sent Friday, was to the point.
Hatch was sent Friday for a magnetic resonance imaging examination.
In an e-mail sent Tuesday morning, Mr. Sandler denied ranting on Saturday.
An e-mail sent Wednesday to Michael Hildebrandt of Stage Entertainment was not immediately answered.
Mr. Harmon signaled his departure might be near with a Tweet sent Thursday.
Fifty-one senators had urged the administration not to sign it in a letter sent Thursday.
The letter to eight companies, including the largest carriers, AT&T, T-Mobile, and Verizon, was sent Thursday.
It is not clear how his recommendation, to be sent Thursday to city doctors, will be received.
The former central intelligence director, James Woolsey, and a former national security adviser, Robert McFarlane, co-signed the letter sent Thursday.
Messages sent Monday to the Twitter accounts of hackers who had claimed credit for the attack went unanswered.
