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Pluto Probe Launches
Artem S. Tashkinov writes "The US space agency, Nasa, has successfully launched its New Horizons mission to Pluto. The $700m probe will gather information on Pluto and its moons before - it is hoped - pressing on to explore other objects in the outer Solar System. Pluto is the only remaining planet that has never been visited by a spacecraft."
For those not aware, had it been delayed past early Feb, the mission would have taken 4 years longer to reach Pluto, due to missing Jupiter for a gravitational 'slingshot' assist.
Roll on 2015. The best images we have of Pluto now are fuzzy Hubble pics, and I can't wait for this to change.
After hearing how this is a flyby mission and the top speed of this spacecraft, I wondered about the current speed champ, Voyager I. According to some of my back of the envelope calculations based upon New Horizons' estimated top speed after a Jupiter assist and the current position and speed of Voyager I, in 26 years New Horizons will surpass Voyager I as the most distant human made object.
"Me fail English, that's unpossible." --Ralphie
What, exactly would I have to appologize for? the actual radiation exposure would be something like being out in the sun slightly longer than you should without sunscreen. That's not great, but frankly if I was concerned about that, I'd make a point of not living within threat range of the cape.
Get over it.
They are very serious about minimizing the exposure, which is why the teams were deployed, but the actual danger is negligable.
No, I wouldn't "appologize". I have nothing to appologize for, and certainly not to you.
"Oh my God. This is terrible. This is the end of my Presidency. I'm fucked."; ~ Donald J. Trump
Watched it go from the beach at 13th Street South in Cocoa Beach, and aside from the fact that it was a real pretty shot, playing peek-a-boo between puffy white clouds on the way up, it was also going like a bat out of hell from the very beginning. From the looks of things, that Atlas V could hardly tell it even had a payload on top. Real fast right off the pad, and then just kept on accellerating from there on. Looked more like a Delta II than any kind of Atlas. Fucker was just flat out gittin' it on the way up. Very spunky look to it for a bird that size.
Is it fascism yet?
Just because you're ignorant of major space exploration events doesn't mean the rest of the world is. Take an occasional read of something like The Space Review. Although there's much debate about the planned manned space architecture there's still plenty going on.
How we know is more important than what we know.
I'm sorry, that's not the way it happened. NASA polls scientists for mission suggestions, not random websites. A mission of this magnitude has to be planned and prepared for, and that takes years. As in more than 6. In fact, this mission has been planned and laid out within NASA for a long time. The reason it took this long to launch is because each new congressional funding bill would slash the mission and then reinstate it the next time around. Signatures don't fund space missions. Congress does.
Sleep is futile.
The RTGs in question here are not just Plutonium slugs.
y /northern_fleet/incidents/31772.html
Remember there have been accidents with them in the past.
During the three mission accidents that did occur, the RTGs performed as predicted. The Transit 5-BN-3 mission was aborted because of launch vehicle failure. The RTG burned up on reentry as designed with the plutonium dispersed in the upper atmosphere. The RTG design was changed shortly after that to accommodate intact reentry. The next accident was with the Nimbus-B-1 that was aborted shortly after launch by a range safety destruct. The RTG was recovered, with no release of plutonium, and the heat sources were reused in later missions
The failure of the Apollo 13 mission meant that the Lunar Module reentered the atmosphere carrying an RTG and burnt up over Fiji. The RTG itself survived reentry of the Earth's atmosphere intact, plunging into the Tonga trench in the Pacific Ocean. The US Department of Energy has conducted seawater tests and determined that the graphite casing, which was designed to withstand reentry, is stable and no release of plutonium will occur. Subsequent investigations have found no increase in the natural background radiation in the area.
In order to minimise the risk of the radioactive material being released, the fuel is stored in individual modular units with their own heat shielding. They are surrounded by a layer of iridium metal and encased in high-strength graphite blocks. These two materials are corrosion- and heat-resistant. Surrouding the graphic blocks is an aeroshell, designed to protect the entire assembly against the heat of reentering the earth's atmosphere. The plutonium fuel is also stored in a ceramic form that is heat-resistant, minimising the risk of vaporization and aerosolization. The ceramic is also highly insoluble.
http://en.wikipedia.org/wiki/RTG
http://www.ne.doe.gov/space/space-desc.html
http://www.nuclearspace.com/facts_about_rtg.htm
http://www.bellona.no/en/international/russia/nav
Nice information about RTG powered lighthouses
To enter orbit around a planet you need to be going slowly when you get there, at no more than the orbital speed for the planet. New Horizons will be going at 11 km/s when it flashes by Pluto, snapping pictures like mad, whereas the orbital velocity for Pluto is just over 3 km/s. NH is moving at least 3 times too fast to go into orbit.
If you wanted to go into orbit, you'd have two choices. The first, and most economical, is to launch the spacecraft on an elliptical trajectory that just barely reaches out to Pluto. That gets the spacecraft there with the lowest possible speed relative to Pluto. You still have some braking to do, but it's the least possible. Problem is, the length of such a trajectory is about half the period of Pluto's orbit, i.e. 125 years. Ugh.
If you speed things up by taking a faster trajectory, then you end up with much more braking to do. Then the problem becomes: how do you lose all that speed? If the planet had an atmosphere, and you have good heat shielding, you can do a little aerobraking, which is what's done with Mars. But with an airless world you're stuck with bringing along enough fuel to do almost as much braking as you did accelerating from Earth orbit. So far, that has been very difficult without a very large spacecraft. One plausible hope for improvement is to bring along a real nuclear reactor (instead of just an RTG) which can provide lots of electric power, and then use a high-efficiency ion drive to slow yourself down.