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New Horizons Phones Home After Pluto Flyby -- Craft Healthy, Data Recorded
Tablizer was one of several readers to note that the New Horizons probe has completed its flyby of Pluto and radioed home to confirm that it went without incident. Mission Ops manager Alice Bowman said the spacecraft was healthy, full of data, and sharing telemetry. The images New Horizon collected haven't been downloaded yet, but NASA decided to tide us over by releasing this high-resolution view from the day before. It was taken when the probe was still 768,000 kilometers away with a resolution of 3.8km per pixel. (Closest approach was approximately 12,500km.) They also released an exaggerated-color image of Pluto and Charon which highlights the non-uniformity of both worlds.
Pictures from closest approach are not yet available. Expect another post late Wednesday or early Thursday with those images. The reason for this is that New Horizons can't take pictures and send them to us at the same time, so imaging activity is interspersed with downlinks to Earth to transmit data. Emily Lakdawalla has posted a downlink schedule. On Wednesday afternoon (ET), the probe will transmit three images of Pluto that were taken from 77,000km away, with a resolution of 0.4 km per pixel. They'll be the first three pieces of a mosaic of Pluto's surface, and the dwarf planet will fill all three frames. It will take a full 16 months for New Horizons to transmit all the data it collects. (Lakdawalla also added Pluto to a montage of the biggest non-planets in the solar system. New Horizon's measurements indicate Pluto is slightly larger than we thought. It's now considered the largest of the Kuiper Belt objects.)
Pictures from closest approach are not yet available. Expect another post late Wednesday or early Thursday with those images. The reason for this is that New Horizons can't take pictures and send them to us at the same time, so imaging activity is interspersed with downlinks to Earth to transmit data. Emily Lakdawalla has posted a downlink schedule. On Wednesday afternoon (ET), the probe will transmit three images of Pluto that were taken from 77,000km away, with a resolution of 0.4 km per pixel. They'll be the first three pieces of a mosaic of Pluto's surface, and the dwarf planet will fill all three frames. It will take a full 16 months for New Horizons to transmit all the data it collects. (Lakdawalla also added Pluto to a montage of the biggest non-planets in the solar system. New Horizon's measurements indicate Pluto is slightly larger than we thought. It's now considered the largest of the Kuiper Belt objects.)
In fact the core technology of the 2 main imaging devices, LORRI and RALPH, was British.
== Jez ==
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In these 10 years since launch, they could have precomputed every possible picture, hash them, and then the probe could have simply sent the hashes instead of the full size pictures.
Just for fun, let's see what it would take for them to pull this off. The LORRI image sensor is 1024x1024 pixels with 12 bits per pixel.
So the number of distinct images divided by the timespan available gives 2^(12*20) / (10 years) = about 5.6 * 10^63 hashes per second.
Let's say you had a CPU capable of computing one such image hash per nanosecond (very optimistic), you'd need 2^(12*20) / (10 years) / (1 nanosecond) = about 5.6 * 10^54 CPUs to pull this off.
For comparison that's an order of magnitude or so more than the number of nucleons in our earth.
If those CPUs consumed 50W of power computing these hashes (again very optimistic), the entire project would consume 2^(12*20) / (1 nanosecond) * (50 watt) = 8.8 * 10^64 joules.
For reference that's two orders of magnitude more than the total mass-energy (including dark matter) of the Virgo supercluster, the supercluster which contains our Milky Way galaxy.
Unless I messed up the calculations that is...