New Horizons mission to Pluto prepares for terrifying silence on Tuesday AM

Because the fun won’t start until the evening

New Horizons spacecraft approaching Pluto

On Tuesday morning at 0449 PDT (1149 UTC), the New Horizons space probe will make mankind’s first visit to Pluto, and there will be much rejoicing; but we won’t actually know if the mission is a success until much later.

At a press conference on Monday the team, some of whom have been working on the project for more than 20 years - and who have been good enough to talk to the Reg about the project - explained that despite all the celebrations planned for tomorrow morning, the real crunch time will come at around 1800 PDT (0100 UTC), when the first signals for the probe are returned.

Space – as Douglas Adams observed – is vastly, hugely, mindbogglingly big, and the New Horizons probe is currently over three billion miles away from home and getting further away at around 25,000 miles (40,233.60 km) per hour. Because of the distances involved, it takes over four hours for a signal to get back to Earth, and at a pathetically low data rate.

To add to the delay, the probe has been programmed not to bother to phone home on flyby day unless something really unforeseen happens. Instead, New Horizons will use all the resources it has to gather as much data on Pluto and its moons in the brief time it has close to the surface.

During this time NASA wants to distract the probe as little as possible, and the spacecraft has been operating on a preset series of flight instructions for the last week, after an unexpected overload temporarily disabled New Horizons.

Since that rather frantic weekend, NASA has made the probe semi-autonomous and has built a "slam code" into the operating system so that if anything looks dodgy they can make the probe shift to full-recording mode automatically.

Thankfully that hasn’t been necessary and all systems are go for the moment. If all goes to plan, the probe will fire up its communications array at the end of the flyby and begin pumping back the data at a frustratingly slow 2Kbps, even with the nifty compression system NASA is using.

The first data NASA is likely to publish are the close up images people are waiting for. Pluto has been little more than a fuzzy dot for mankind, and scientists and some of the rest of us are salivating at the thought of seeing what the dwarf planet looks like up close and personal.

We may yet be disappointed. While the route the probe has taken was carefully scouted out ahead of time by the Hubble Space Telescope and other instruments, their capacity is limited and there may well be tiny orbiting dust motes that could completely bugger the probe.

At the kinds of speeds New Horizon’s probe is going, a small micrometeorite hit head on will utterly destroy it. A less serious impact with a smaller piece of matter could put it into a spin that would destroy any data-gathering capabilities the probe has, rendering its nearly 10-year mission a failure.

Needless to say Tuesday will be tense. But even if the probe is destroyed there would be one bright side, since the man who discovered the then planet might come to rest on it – or at least part of him.

Clyde Tombaugh, who discovered Pluto in 1930, is actually traveling on the New Horizons probe, or at least one ounce of his ashes are. He gave his blessing to the mission in the 1990s, and after his death the family released the ashes to be built into an inscribed container on the spacecraft.

Hopefully though, Tombaugh and the probe he enabled will carry on past Pluto and out into the Kuiper belt that encircles the Solar System. Once out there, New Horizons could still have a few more surprises left for us yet. ®




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