Engineers calculated that the spacecraft, traveling a scorching 8,700 mph, bombed into the planet’s heavily pockmarked surface at 3:26 p.m. ET Thursday. It was not a gentle goodbye: The impact was expected to pulverize the car-sized spaceship and gouge out a 50-foot crater — big enough to accommodate a school bus — near Mercury’s north pole.
Engineers calculated that the spacecraft belly-flopped onto the cratered terrain on the far side of Mercury, when the ship was out of contact with Earth.
“We monitored Messenger’s beacon signal for about 20 additional minutes,” said mission operations manager Andy Calloway of the Johns Hopkins University Applied Physics Laboratory. “It was strange to think during that time Messenger had already impacted, but we could not confirm it immediately due to the vast distance across space between Mercury and Earth.”
“We’re really sad to see this, because Messenger has been a fabulous mission,” Brown University’s James Head, a co-investigator on the mission, said before the impact. “It’s an exhilarating time, but also really poignant.”
At least Messenger went down with a fight and in a blaze of glory. Edging ever closer to Mercury because of the effects of the sun’s gravity, the ship, its fuel tanks dry, was supposed to meet its destiny in March. But creative engineers bought their craft an extra month of life by repurposing Messenger’s stockpile of helium, used to pressurize the fuel tanks. Leftover helium was expelled from the spacecraft’s thrusters, nudging the ship away from the looming surface.