October 17th, 2012 by James Ayre
We’re only two and a half years away from seeing what Pluto looks like close up. Until now, we’ve only had very grainy pictures to give us an idea of what it’s like. The New Horizons spacecraft, created and guided by NASA, is about seven years into its nine-and-a-half year journey across a huge swath of our solar system, all the way to Pluto and its satellites. Currently estimated to arrive in January 2015, New Horizons will be the first time we encounter such a distant world, culminating in a very close flyby of Pluto on July 14, 2015.
Since New Horizons began its pioneering journey, the science team has been becoming more and more aware of “the possibility that dangerous debris may be orbiting in the Pluto system, putting NASA’s New Horizons spacecraft and its exploration objectives into harm’s way.”
“We’ve found more and more moons orbiting near Pluto — the count is now up to five,” says Dr. Alan Stern, lead investigator of the New Horizons mission and an associate vice president of the Space Science and Engineering Division at Southwest Research Institute. “And we’ve come to appreciate that those moons, as well as others not yet discovered, act as debris generators populating the Pluto system with shards from collisions between those moons and small Kuiper Belt objects.”
“Because our spacecraft is traveling so fast — more than 30,000 miles per hour — a collision with a single pebble, or even a millimeter-sized grain, could cripple or destroy New Horizons,” adds New Horizons Project Scientist Dr. Hal Weaver of the Johns Hopkins University Applied Physics Laboratory, “so we need to steer clear of any debris zones around Pluto.”
Nearly every tool available is already being used by New Horizons to look for debris that may cause problems. This includes: state-of-the-art computer simulations projecting the stability of the debris orbiting Pluto, the best ground-based telescopes, Hubble Space Telescope, and ‘stellar occultation probes’ of the Pluto system.
During all of this, they have also been developing alternative, but more distant, paths through the Pluto system. These would still allow the primary science missions to be accomplished but would be further away, and hence without the ultra-high-resolution images of Pluto that are so exciting sounding. These alternate paths will only be used if the team decides that the current flyby plans are too ‘hazardous.’
“We’re worried that Pluto and its system of moons, the object of our scientific affection, may actually be a bit of a black widow,” says Stern.
“We’re making plans to stay beyond her lair if we have to,” adds Deputy Project Scientist Dr. Leslie Young of Southwest Research Institute. “From what we have determined, we can still accomplish our main objectives if we have to fly a ‘bail-out trajectory’ to a safer distance from Pluto. Although we’d prefer to go closer, going farther from Pluto is certainly preferable to running through a dangerous gauntlet of debris, and possibly even rings, that may orbit close to Pluto among its complex system of moons.”
Stern finalizes it by saying: “We may not know whether to fire our engines on New Horizons and bail out to safer distances until just 10 days before reaching Pluto, so this may be a bit of a cliff-hanger. Stay tuned.”
Source: Southwest Research Institute
Image Credits: Courtesy JHUAPL/SwRI; Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)
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