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."

Yes!!!

[lorelorn]

With all the delays, I was getting worried that the mission would be delayed.

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.

Most distant human object...

[00Sovereign]

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.

Re:Don't suppose the No Nukes freaks will apologiz

[Gojira Shipi-Taro]

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.

Re:Fastest too..

[DoraLives]

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.

Re:Question for the white house

[QuantumG]

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 [thespacereview.com]. Although there's much debate about the planned manned space architecture there's still plenty going on.

Re:The website that changed policy

[Anonymous Coward]

NASA was not against a mission to Pluto. This mission has been in the works for years. The problem was convincing the politicians for the funding. That website had 0.000000000000001% to do with this mission. NASA didn't plan, design, buid, and launch a Pluto probe within a span of 5 years.

Re:Kinda Slow

[borisborf]

I do have to agree with the R&D years ahead of time thing. My dad works for Honeywell Defence and Space Center and they are the ones that make the processors for stuff like this.

Shocked one time to find out that a new sattelite was going up with a years-old PPC processor running at something crazy like 333MHz, I asked him what all this was about.

Apparently, to get these chips made, they have to wait until Motorola releases a processor. Then they get a contract from the military. So they take the current processor and spend years taking it from consumer-grade to military-grade and Rad-Harding the chip. Then once the part is done, they put it in the probe which is still a few years from launch. All in all, you have a minimum of a 5 year technology gap for what is going up and what is current.

Re:The website that changed policy

[Zen Punk]

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.

Re:Kinda Slow

[Cujo]

You're probably thinking of JPL's PKB Express, which was cancelled. New Horizons started cutting metal in earnest around 2003, which is when they had their CDR. Most of their flight avionics was completed in 2004, wich is also when most of their flight software saw it first release. Long lead time isn't the reason they didn't use an ion engine. The reason is that given the current state of ion engine technology, it would be a bad idea - especially when they had a mission design that closed with a relatively low risk ELV.

Ion engines are great for some missions, but have two major drawbacks - they require lots of power, and they provide very low thrust with consequent long trip times. When you're flying to Pluto, an RTG is your only real power option, and you get about 200 Watts and dropping. Using multiple RTGs wasn't an option for several good reasons. Bottom line - you need to get to Pluto fast if you want to have any power to do science there.

Re:Don't suppose the No Nukes freaks will apologiz

[HardCase]

While you're researching, you might want to check to see just how readily plutonium oxidizes in the presence of heat. Rapid oxidization, or burning, produces a somewhat different effect than liquifying.

Oh, and the amount of plutonium is roughly a handful.

-h-

Re:Don't suppose the No Nukes freaks will apologiz

[Wyatt Earp]

The RTGs in question here are not just Plutonium slugs.

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 [wikipedia.org]
http://www.ne.doe.gov/space/space-desc.html [doe.gov]
http://www.nuclearspace.com/facts_about_rtg.htm [nuclearspace.com]

http://www.bellona.no/en/international/russia/navy /northern_fleet/incidents/31772.html [bellona.no]
Nice information about RTG powered lighthouses

Re:Kinda Slow

[DerekLyons]

Shocked one time to find out that a new sattelite was going up with a years-old PPC processor running at something crazy like 333MHz, I asked him what all this was about. [...] All in all, you have a minimum of a 5 year technology gap for what is going up and what is current.

Which sounds shocking - until you realize these birds are not running Quake or Halo. The OS they use demands much less system resources (and wouldn't be reconizable as an OS to most computers geeks to start with) and is much more tightly optimized than what you'll find in the consumer market. Many tasks can accomplished with far less computing power than many users realize because all the cruft that a PC, regardless of OS, has simply doesn't exist in these (spaceborne) systems.

The gap also allows time for all the bugs and idiosyncrasies of the processor to be figured out and coded around.

Re:BB frikkin' C!

[DerekLyons]

How little does the American public care about this launch? So little that we've got to look to British news outlets to find decent coverage!

It's linked right off the home page of CNN [cnn.com] and it's headline news (with a big beautiful picture) on MSNBC's Science and Technology [msn.com] section. (As well as ABC's [go.com] and CBS's [cbsnews.com] news departments Science and Technology pages.) Its also the lead story on Google News's Sci/Tech [google.com] section.

As a matter of fact - this list [google.com] from Google news shows a pretty even balance between US and the rest of the world in coverage. Blame the Slashdot editor, not the media on this one.

Crow tastes pretty good with Tabasco.

oy, big problems here

[Quadraginta]

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 [wikipedia.org] 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 [nasa.gov] (instead of just an RTG) which can provide lots of electric power, and then use a high-efficiency ion drive to slow yourself down.

Re:Don't suppose the No Nukes freaks will apologiz

[Keebler71]

You mean like Nuclear Magnetic Resonance Imaging (NMRI) [wikipedia.org]? What? You've never heard that with the "N"?

Cargo onboard the Probe...

[Rhoon]

3 Cameras and a bit of plutonium aren't the only cargo [smh.com.au] onboard the probe.

THE first space mission to Pluto contains an unusual piece of cargo: ashes from the cremated remains of Clyde Tombaugh, the astronomer who discovered the outermost planet in 1930.

Re:oy, big problems here

[Anonymous Coward]

A correction about the Hohmann transfer time:

The semimajor axis of the ellipse is about half Pluto's, which means that the revolution time is about (1/2)^(3/2) that of Pluto (Kepler's third law). You have only to go out to Pluto, not back to Earth's orbit, so the time needed is only half the revolution time. This gives an approximation of

(1/2)^(3/2) * (1/2) * 248 years = 44 years