I am sure many of you have been watching New Horizons approach Pluto recently. It is one of the those things that has been a long time in the works and will finally be here tomorrow (although it will take a little while for the flyby images to get beamed back and 18 months for all the data to be transferred back).
I have been into astronomy since was very young. I grew up watching the Voyagers send back striking images of Jupiter, Saturn, Uranus and Neptune. The elusive Pluto remained unexplored (Voyager 2 could have explored Pluto but they had to make a choice: a flyby of Neptune's large Moon Triton or Pluto...didn't have the fuel for both...Triton won that battle).
Even with the Hubble Space Telescope, Pluto was only a few pixels revealing a couple of light and dark areas. Several proposals were made to send a probe to Pluto...NASA rejected several of them before finally funding New Horizons.
New Horizons launched in 2006 and got a gravity assist from Jupiter to speed the journey. Even a very small satellite put atop a very powerful rocket has taken almost nine and a half years to reach this remote world...and it's not staying long.
New Horizons is traveling over 30,000 miles per hour and will come within about 7,700 miles of Pluto's surface. Since the resolution of its imagers depend on how far the satellite is from Pluto, it has very little prime imaging time. If you are twice as far from Pluto, you pics have half the resolution. Even just one hour after closest approach, the distance to Pluto will go from about 7,700 miles to about 37,000 miles so the pics will have less than 1/4 the resolution so you can see why you want to get as much data at that time as you can!
So why not slow down or better yet, go into orbit? Remember that 9.5 year journey there? If you want to go into orbit, you to to slow down to match Pluto's speed. That would require a LOT of fuel. We just can't loft a satellite up there with that much fuel on board. The other option of course is to launch a slower moving satellite that wouldn't need as much fuel to slow down but then it would take a LOT longer to get there. Hence a flyby (New Horizons like to brag that it took them 9 hours to pass the Moon's orbit but the Apollo astronauts took three days...we could have gotten the astronauts to the Moon quicker, but they wanted to stop, land, explore a bit, turn around and come back).
And I don't care if Pluto is a dwarf planet. I hate that the media says Pluto was "demoted. It's not a competition people! It was reclassified to better reflect how different it is from all the other solar system bodies. A dwarf planet is NOT an insult, does not imply less important or less interesting. That Pluto is the first Kuiper belt object to be explored makes it MORE special and if you are pouting about it being called a dwarf planet, you are missing an important point.
I have been waiting most of my life. The pics that have come back so far have been thrilling to see, Christmas every day for the last week or so. No pics will be sent back tomorrow...like I said, no time for that when you only have a few hours...cameras will be clicking away...quick look data will start coming in Wednesday and I will be glued to the computer watching for it.
As exciting as this is, I already fear that it is the only time Pluto will be visited in my lifetime. It takes a long time to design, build and launch a probe to Pluto and a long time to get there. An orbital mission would take longer than 10 years travel time after launch and I am not award of anything coming down the pipe that will reduce any of those time frames. Heck, we are only going to get really good pics of one side of Pluto...and there are (at least) five Moons out there too that need exploring!
One consolation is that New Horizons should go on to explore at least one other Kuiper Belt object...they will select which one and fire up the thrusters to set a course later this year (there are a couple of candidates they could reach with the available fuel) so hopefully there will be another exciting flyby a few years down the road.
After a lifetime of waiting, that little dot I saw in pictures in my astronomy books as a child is about to be revealed in all its glory and I am thrilled to be able to watch it happen.