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Fraser
2005-Jun-22, 07:40 PM
SUMMARY: The New Horizons mission to Pluto has been called “The First Mission to the Last Planet,” and it’s the first mission to venture to a “new” planet since the Voyager missions nearly 30 years ago. While New Horizons includes proven technology and a superior launch vehicle, it could be considered to be a ‘throw-back’ mission. Some of the scientific instruments on board are named after characters from the 1950’s television show, “The Honeymooners,” and the project’s Principal Investigator, Dr. Alan Stern of the Southwest Research Institute, says the mission makes him feel like he’s back in the heyday 1960’s or 1970’s of space exploration because this mission is all about exploring planets for the first time.


View full article (http://www.universetoday.com/am/publish/new_horizons_zoom_pluto.html)

What do you think about this story? Post your comments below.

piersdad
2005-Jun-22, 08:03 PM
At best speed, the spacecraft will be traveling at 50 km/second (36 miles/second), or the equivalent of Mach 85. Stern compared the Atlas rocket to other launch vehicles. “The Saturn V took the Apollo astronauts to the moon in 3 ˝ days,” he said. “Our rocket will take New Horizons past the moon in 9 hours. It took Cassini 3 ˝ years to get to Jupiter, but New Horizons will pass Jupiter in just 13 months.”
mach 85 for 9 years thats motoring

antoniseb
2005-Jun-22, 08:49 PM
Originally posted by piersdad@Jun 22 2005, 08:03 PM
mach 85 for 9 years thats motoring
It woun't be going Mach 85 for nine years. It will slow down a lot as it climbs out of the well. It will speed up a little as it zips passed Jupiter, and then continue to slow down.

The Journey is about 3.2 billion miles. Nine years is 280 million seconds. On average it will be going 11.25 miles/second which is about Mach 55. I don't know where the Mach 85 came from... 36 miles/second should be Mach 185.

Midnight_Toker
2005-Jun-22, 08:53 PM
isn't mach an equation between speed and air density, i dont think something can be going mach, in space since it's a vacuum, but i'm not sure, correct me if i'm wrong.

lswinford
2005-Jun-22, 09:00 PM
I just read a fun comparison (off of a NASA page I think) of the relative distances in the solar system. On a football field (American-style, sorry), the sun was a dime placed on the goal line. Earth was a spot a fraction of a millimeter in size, placed on the two-yard line. Jupiter was somewhere about the 10-yard line. Pluto, though, was some 70, almost 80, yards out from the sun. :blink:

I'm glad they're giving this a fast ship. :lol:

antoniseb
2005-Jun-22, 09:00 PM
Originally posted by Midnight_Toker@Jun 22 2005, 08:53 PM
i'm not sure, correct me if i'm wrong.
You're not wrong, though the speed Mach 1 is generally used to mean about five seconds per mile, and the term was probably used in this article to compare how fast this object is going comapred to fast airplanes (that maybe hit Mach 3). In this case, it may be misleading to use the term in one sense, but justified by the visual image it conjures up.

Spacemad
2005-Jun-22, 09:55 PM
This is an exciting time to live in - we have space flights to the Moon & planets & even a couple of spacecraft leaving the Solar System to enter instellar space - now we have a first time mission to the last planet! Fantastic!!! :)

I've been following this mission for some time & I would dearly love to see it start on its 15 year mission in January 2006.

I'm subscibed to their newsletter so I keep up to date with the mission. :)

aeolus
2005-Jun-22, 10:44 PM
It amazes me how precise the whole journey is, especially when they talk about the possibility of arriving a year later because of a launch delay of a few days.

John L
2005-Jun-23, 03:28 PM
I was one of the others that fought along with the Planetary Society to keep this missions funded. Now, after so many years it will finally be lifting off next January. I'm just glad they found a way to get it there in 9 years.

Greg
2005-Jun-23, 04:19 PM
The dust experiment is a nice addition. Related to this, I wonder how long the craft will remain powered, and whether it can be used to measure the pioneer anomaly. It may have extended life and reveal a few surprises in the Kuiper belt or even the oort cloud. Any craft exiting the solar system will be slowed by the negative acceleration towards the sun, but only to a point. Once it has sped up past escape velocity, it cannot be stopped, unless it's trajectory is changed to make it go into orbit.

antoniseb
2005-Jun-23, 04:30 PM
Originally posted by Greg@Jun 23 2005, 04:19 PM
I wonder how long the craft will remain powered, and whether it can be used to measure the pioneer anomaly.
The craft has a power source with an 88 year half-life, so it should be able to do somewhat limited science for a very long time. It will not, however, be of much use as another tool to measure the Pioneer anomaly, just as the Voyager spacecraft were not. The Pioneer 10 & 11 spacecraft were spin stablized, and so didn't need any extra thruster use after their last planetary encounter. Like the Voyagers, New Horizons will not simply coast on the way out.

Like you I hope it will last a long time, and observe some interesting objects along the way. In about 250 years to get to the aphelion of Sedna's orbit. It will be a few thousand years to get to the Oort cloud. It should be pretty dead by then.

suitti
2005-Jun-23, 05:03 PM
I'm glad I'm not the only one to check the math. Mach 85. As air density goes down, the speed of sound slows too, so your mach number goes up. As the air density approaches a vacuum, the speed of sound should approach zero, and your mach number should approach infinity. So, To Infinity, and Beyond! could be the motto - that is if Disney won't object. On the New Horizons site (http://pluto.jhuapl.edu/) they wimp out with To Pluto and Beyond.

Didn't Deep Space One prove ion thrusters work? If you have an RTG kicking out power, perhaps it makes more sense to use it to generate high ISP thrust. Sure the craft is heavier and starts out slower, but it should make up the time with low thrust over a long time. At this point, it's moot to make design changes. Perhaps this was obvious enough that someone at least looked at it.

Greg
2005-Jun-23, 05:52 PM
Thanks Antoniseb for looking the information up. It will save me the effort. Since I am at work I would have had to post it later in the day when I had the chance. The craft might still have some power in 250 years, but I doubt it will be anywhere near sedna. Hopefully its trajectory will take it near a object yet to be discovered ot it will have some propellant left to alter it to fly by one.

Guest_Ender
2005-Jun-24, 12:45 PM
Anyone know if this thing will eventually be farther then the voyagers since it's going so fast?

Nereid
2005-Jun-26, 11:15 PM
Originally posted by Guest_Ender@Jun 24 2005, 12:45 PM
Anyone know if this thing will eventually be farther then the voyagers since it's going so fast?
Very likely, though it depends somewhat on various 'close encounters' and use of thrusters.

Which also highlights the mission's use for probing the heliosheath, etc. AFAIK, there's only one mission actually planned to study the transition region, and the ISM in situ, an ESO mission (IIRC).

For studying the Pioneer anomaly, LISA will do a far, far better job than a Pioneer-like Pluto probe could ever do ... unless the effect doesn't occur in the solar system region where LISA will operate.

soloh
2005-Jun-28, 02:04 PM
The pluto adventure was long over due... By now we should be talkin of going to the sun.
But am very glad such a speed could be attained :D

antoniseb
2005-Jun-28, 03:29 PM
Originally posted by soloh@Jun 28 2005, 02:04 PM
now we should be talkin of going to the sun.
There have been some proposed missions for making closer inspections of the sun. Getting to the Sun is difficult using chemical rocket technology since you need to change the speed of the spacecraft more than twice as much as the launch to Pluto. However, if Solar sails are ever made to work, or perhaps using Solar powered Ion drives, such a mission is starting to look more economically feasible (let's say with a launch in the next ten or twenty years).

A solar mission could potentially be used to explore and sample the inner corona, but that would take some creative heat shielding.

lswinford
2005-Jun-30, 09:36 PM
Shielding indeed! I can see it now, the collector capsule (this time) gets correctly snagged in air and when the material is analyzed its chemical composition is identicle to the ablation residue of the shielding. :lol:

antoniseb
2005-Jun-30, 09:46 PM
Originally posted by lswinford@Jun 30 2005, 09:36 PM
Shielding indeed! I can see it now, the collector capsule (this time) gets correctly snagged in air and when the material is analyzed its chemical composition is identicle to the ablation residue of the shielding.
I was thinking more of shielding it with something like a long tank tread on a T shaped track where any one place on the tread (or belt) is being heated by the sunlight for a small fraction of the time, and is radiating heat from the shadow the rest of the time.

antoniseb
2005-Aug-30, 07:56 PM
There is a story on SlashDot yesterday:
http://science.slashdot.org/article.pl?sid...tid=236&tid=162 (http://science.slashdot.org/article.pl?sid=05/08/29/1657212&tid=236&tid=162)

Which says that New Horizons will return to the inner Solar System in 50,000 years. As tfisher on the www.unmannedspaceflight.com forum points out, it seems to me I've only heard of NH wizzing past Pluto faster than Solar escape velocity. No other web-site that I've looked at has said anything about NH returning. Does anyone here know something about this?