New Horizons closest approach to Pluto tomorrow

Update:  NASA has released a higher resolution photo of Pluto, now seen above.  This is the last photo taken and sent back to Earth by New Horizons during its approach phase.  After this picture was transmitted back to us, the probe turned its attention to the flyby of Pluto.  It passed by its closest approach to Pluto this morning at 7:49 EDT and is still furiously gathering data and snapping pictures as Pluto recedes into the distance behind it.  It will send its first “encounter success” message tonight around 8pm EDT.  Receipt of this message will reassure scientists that the probe did not collide with any debris as it zoomed through the Pluto system at over 31,000 mph.  We await this signal and hope for the best.

Very rarely do we get to see a solar system body close-up for the first time.  Tomorrow the New Horizons spacecraft, launched in 2006, will zip through the Pluto system and frantically gather data and photographs at resolutions that far exceed what we can see from Earth.

Pluto is almost 30 times farther from the Sun than we are here on Earth, so even the Hubble Space Telescope has been unable to provide more than faint glimpses of what the surface of Pluto might look like.  That will all change tomorrow as our trusty robotic explorer will become our eyes and ears in its close fly-by to Pluto and its giant moon, Charon, plus all the other smaller bodies that orbit the system.  New Horizons will pass within about 7800 miles of Pluto, after a journey of over 3 billion miles, providing high-resolution photography for the first time.

Why not stop and go into orbit around Pluto as, for example, Cassini did at Saturn?  That would be lovely, but in order to get New Horizons to Pluto as quickly as possible (a trip that still took over 9 years) we put this small spacecraft on top of the largest rocket money could buy in 2006 and sent it out to rendezvous with Pluto at the highest possible speed.  New Horizons has no rocket engine or fuel on board to slow down, just scientific instruments which were designed to capture photos and data during the days and weeks before and after closest approach as well as during the one and only close pass we will get.  Similar to a tour bus driver who won’t stop or slow down, the passengers have to “keep their eyeballs moving!”

We won’t see live video or pictures from the closest approach for some weeks afterward.  In order to transmit back to earth, the spacecraft has to be turned so its antenna points to us.  However this would mean that the scientific instruments on board would not be pointing at Pluto, which would be rather silly after all this effort to get there.  So all the data will be captured and stored on board in the equivalent of a giant USB thumb drive.  Once the spacecraft is through the Pluto system, it will be re-oriented and will begin the long process of sending thousands of pictures and hundreds of megabytes of scientific data back to waiting scientists.

However, scientists have been able to send back a few early images, like the one in this post, giving us a tantalizing glimpse of Pluto’s surface.  So much more to come, so stay tuned to the web!  I really enjoy following Emily Lakdawalla’s blog posts on the Planetary Society website.  Emily will be on-site at New Horizons HQ to give us all the latest information.  As a trained planetary geologist and award-winning writer, she has become my number-one source for the latest information about missions like this.  NASA’s website will also be giving frequent updates as will NASA TV which is available online as well as by satellite.


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