Shortly after midnight one morning this month, the spacecraft launched last year from Virginia ended its mission to the moon by crashing into the lunar surface, authorities said.
NASA said it has confirmed that the crash, which had been planned, occurred between 12:30 a.m. and 1:22 a.m. Eastern time on April 18. On Earth, such an impact could be expected to make enough of a bang to rouse many of those asleep at the time.
But the moon is different. One goal of the mission was to study what scientists call the atmosphere of the moon, which is so sparse that it differs little from a vacuum.
Lack of an atmosphere to carry sound, a NASA spokeswoman said by e-mail, meant no noise.
But NASA scientists expressed confidence that the spacecraft did indeed crash.
It had been sending radio signals, which need no atmosphere. From the cutoff of those signals, NASA can determine “when and where” the spacecraft struck the lunar surface, said Rachel Hoover, a spokeswoman for NASA’s Ames Research Center in California.
Project personnel also think that when the spacecraft hit, it hit hard.
Millions along the Eastern Seaboard saw the fiery track of the rocket that carried the spacecraft aloft. When the craft struck the moon this month unseen and unheard, Elphic, the NASA scientist, said it was racing at three times the speed of a rifle bullet. At such speeds, he said, “there’s nothing gentle about impact.”