New Horizons probe reconnects with Earth after journey past dwarf planet.
NASA's New Horizons mission phoned home on the night of 14 July, sending a burst of telemetry data that confirmed it had successfully flown past Pluto in the first-ever visit to the dwarf planet. Engineers and scientists in mission control, at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, erupted into cheers just before 9 p.m. Eastern time as the signal appeared, as a strings of 1s and 0s, confirming that a deep-space antenna in Madrid had locked onto the spacecraft's signal.
”We have a healthy spacecraft,” said missions operation manager Alice Bowman. “We are outbound from Pluto.”
New Horizons' computer memory was full of science data, mission controllers confirmed.
The success capped 13 hours of waiting, after New Horizons skimmed 12,500 kilometres above Pluto's surface just before 7:50 a.m. Eastern time. The probe had been radio silent, not communicating with mission control since late the night before — on purpose, so that it could focus on gathering hundreds of scientific observations of Pluto and its moons.
NASA is expected to release the first high-resolution images from the close encounter on 15 July.
Initial images, taken before the close approach, reveal a world of astonishing geological detail. Huge patches of light and dark coloration mottle Pluto's surface; most prominent among them is a giant light-toned region that resembles a heart. It rests in the northern mid-latitudes on the hemisphere of Pluto that faced New Horizons during the close approach.
Annette Tombaugh, daughter of Clyde Tombaugh, who discovered Pluto in 1930, said that her father would have liked that his planet had a heart.
Early data on the chemical composition of Pluto suggest that the heart is not a single unit — it is, in fact, broken in two. The left-hand side of the heart appears smoother and brighter, while the right-hand side is rougher, said Jeff Moore, a mission scientist from NASA's Ames Research Center in Mountain View, California. The right-hand side also appears to have more impact craters, which are surprisingly partially eroded.
The images have prompted planetary scientists to reconsider what they thought they knew about Pluto. “Until yesterday our best analogue was [Neptune's moon] Triton,” said team member John Spencer, of the Southwest Research Institute in Boulder, Colorado. “But the closer we look at Pluto, the less it looks like Triton.”
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Witze, A. Scientists jubilant as Pluto mission phones home — safe. Nature (2015). https://doi.org/10.1038/nature.2015.17983