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Scientists Plan Pluto Flyby
BBC ^ | 2-26-2002 | David Whitehouse

Posted on 02/26/2002 6:45:06 AM PST by blam

Tuesday, 26 February, 2002, 15:05 GMT

Scientists plan Pluto flyby

Golden opportunity to study Pluto

By Dr David Whitehouse
BBC News Online science editor

Many scientists are keen to plan for a Pluto encounter as the planet and its large moon, Charon, represent one of the true frontiers in the solar system that no spacecraft has ever visited.
This is despite the fact that the money for a mission to Pluto is in jeopardy as Nasa contemplates its future spending plans.

If scientists do not make plans now and be ready to act swiftly if the money becomes available, they may miss a golden opportunity to study the planet at the end of the Solar System.

They say if they do not get there soon, they may miss amazing sights that will not reoccur for almost 250 years.

Jupiter first

There are two reasons why scientists want to get there as soon as possible. The first has to do with its atmosphere.

Since 1989, Pluto has been moving farther from the Sun and as it gets colder its atmosphere will freeze out, so researchers want to arrive while there is a chance to see it.

The second reason is to map as much of Pluto and Charon as possible. The longer we wait, the more of Pluto and Charon will be shadowed for decades impeding the spacecraft's ability to take pictures in reflected sunlight.

Celestial mechanics say that an opportunity to launch to Pluto by way of Jupiter, which gives it a gravity kick, occurs in January 2006.

But given the uncertainty about the money that do not provide much time to get a probe designed and built. But if it does get off, scientists know what they want to do.

From Earth, the spacecraft will head to Jupiter, arriving just over a year later. Passing the Jovian system at 80,500 km per hour (50,000 mph) it will move on a trajectory that will arrive at Pluto and Charon as early as 2015.

The cameras on the spacecraft will start taking data on Pluto and Charon a year before it arrives and about three months from the closest approach - when Pluto and Charon are about 160,000 kilometres (100,000 miles) away - the spacecraft can make the first maps.

One day only

The busiest part of the Pluto-Charon flyby lasts a full Earth day. On the way in, the spacecraft will make the best global maps of Pluto and Charon in green, blue, red, and a special wavelength that is sensitive to methane frost on the surface.

The spacecraft will get as close as about 9,600 kilometres (6,000 miles) from Pluto and about 27,000 kilometres (17,000 miles) from Charon. During the half hour when the spacecraft is closest to Pluto or its moon, it will take close-up pictures in both visible and near-infrared wavelengths. The best pictures of Pluto will depict surface features as small as 60 meters (about 200 feet) across.

But even when it has sailed past Pluto the spacecrafts scientific life is far from over.

After passing Pluto it will retarget itself for an encounter with a Kuiper Belt Object (KBO) - one of the many large chunks of rock and ice that have been found in the cold outer reaches of the solar system in the past decade.

The team has not yet identified their target KBO, but scientists expect to find one or more the spacecraft can reach that are 50-100 kilometres (about 30-60 miles) across.

With so much pioneering science that such a probe could do researchers know they can make a case for the Pluto probe. They just hope that the politicians are listening.

Despite their proximity, Pluto and Charon are covered with bright frosts of differing compositions.

Water ice covers Charon, while Pluto's surface is predominantly nitrogen frost with traces of methane and carbon monoxide ices.

The Pluto/Charon system has a highly elliptical orbit around the sun. In 1989, Pluto was as close to the Sun as it gets during its long year - less than 30 astronomical units (AU), or 30 times the distance between Earth and the Sun. That distance nearly doubles just half a Pluto year later, to 50 AU in 2123.

As Pluto recedes from the Sun, much of its thin nitrogen atmosphere will condense as frost on the surface. This periodic reappearance of fresh frost takes place every Pluto year (248 Earth years) and is the reason that Pluto's is one of the most reflective surfaces in the solar system.


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1 posted on 02/26/2002 6:45:06 AM PST by blam
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To: RightWhale;callisto
FYI.
2 posted on 02/26/2002 6:46:28 AM PST by blam
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To: blam
When I was done reading this, I was going to call you. Then I saw you had posted it. Oh well, ping anyway.
3 posted on 02/26/2002 6:52:01 AM PST by farmfriend
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To: blam

Notes:


I hesitate to explain things that are so well known to everyone present here, but please humor me because I am a physicist, and therefore must start at the beginning.
The rocket equation, derived from the requirement that the change in the total momentum must be zero, demonstrates that the change in velocity of the rocket is the product of the exhaust velocity times the logarithm of the final to initial mass. The exhaust velocity is traditionally given in terms of specific impulse (Isp) times the acceleration of gravity. Rating the various types of rockets that have been invented by their specific impulse tells us how “efficient” the rocket uses its fuel supply. On this basis, photons or light provide the most efficient use of fuel, because they travel at the maximum exhaust velocity permitted by physics—the speed of light. (If the rocket doesn’t carry its own fuel, say, by reflecting photons from the Sun, then some would say that the Isp is infinite.) From this brief survey it is apparent that photon propulsion is the best we can do. The importance of Isp is shown by the next slide.
4 posted on 02/26/2002 7:06:14 AM PST by vannrox
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To: blam


Notes:




NASA has stated that it would like to travel to the last planet remaining unvisited. It took Voyager around 16 years to make it to the orbit of Pluto, though Pluto missed the appointment. Now, 24 years later, it would seem that we should be able to arrive at Pluto much faster, so I have arbitrarily selected a 10x faster trip, or 1.6 years. Well it is easy enough to calculate the speed needed, we take the (average) orbital distance to Pluto, and divide by the number of seconds in 1.6 years, to get an average speed of about 100 km/s. This is the change in velocity needed in the rocket equation. Then selecting various specific impulses, Isp, we find that the ratio of the mass of the rocket to the mass of the payload is as given in the table. Note that a “good” Isp of around 10,000, permits a reasonably sized payload to make it to Pluto in 1.6 years. I’m glossing over another problem, of course, that high Isp rockets are generally energy starved, and would need a small nuclear reactor to provide the power for the thrust. But since everything to date has been launched by chemical rockeds, and even advanced chemical fuels will not exceed 400s of Isp, it should be clear that if we are in a hurry, we can’t get anything to Pluto much larger than a pencil eraser.
5 posted on 02/26/2002 7:08:10 AM PST by vannrox
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To: vannrox


Go HERE to find out more...


6 posted on 02/26/2002 7:12:24 AM PST by vannrox
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To: vannrox

Pluto-Kuiper Express


... to explore Pluto/Charon and the fringes of our Solar System




2000/09/13 - A NASA stop work order was issued for the Pluto-Kuiper Express mission. Further direction from NASA had been given to develop a new mission to reach Pluto before 2020.


The new mission to explore the last planet in our Solar System has been selected. Called New Horizons, this mission will be managed by Johns Hopkins University, Applied Physics Laboratory.

7 posted on 02/26/2002 7:15:34 AM PST by vannrox
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To: vannrox
Yes, that's why they want to use the Jupiter gravity-assist to get oout to Pluto. That's also why the urgency to launch by 2006.

Unfortunately, this mission was "sold" in the current budget as a pork-a-tron add-on by Sen. Barbara Mikulski (D-MD) as a way to funnel money to Johns Hopkins-APL in Maryland. This side-stepped OMB and the White House, something they generally tend to frown on -- the OMB guy who got particularly shafted in this transaction is one Sean O'Keefe. That name familiar? He's the current NASA Administrator.

Good luck on getting funding for PFF in this year's budget. The current OMB doesn't even include it.

8 posted on 02/26/2002 7:16:33 AM PST by Cincinatus
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To: vannrox
Nice presentation.
9 posted on 02/26/2002 7:18:24 AM PST by <1/1,000,000th%
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To: blam
All that to study Pluto? Whats the big deal? Why waste all that money, and why all the expensive rocketry?


10 posted on 02/26/2002 8:06:01 AM PST by Paradox
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To: blam
If scientists do not make plans now and be ready to act swiftly if the money becomes available

Project engineers and scientists are going full-bore ahead. The funding is in the federal budget. Pretty much a done deal.

11 posted on 02/26/2002 8:32:11 AM PST by RightWhale
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To: RightWhale
Project engineers and scientists are going full-bore ahead. The funding is in the federal budget. Pretty much a done deal.

Does the design include wheels in case of unforseen circumstances?

12 posted on 02/26/2002 8:38:34 AM PST by Willie Green
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To: Willie Green
It'll never fly.
13 posted on 02/26/2002 10:38:50 AM PST by Contra
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To: Willie Green
Does the design include wheels

Wheels are used to save an entire year off transit time to Pluto. They will further save money by using green neon skateboard wheels.

14 posted on 02/26/2002 10:42:13 AM PST by RightWhale
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To: blam
Rather Pluto than - Ur-anus ;)
15 posted on 02/26/2002 10:46:00 AM PST by Revelation 911
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To: Paradox
Whats the big deal?

They want to see what is there, like prospecting for gold. Pluto may be rich in materials useful to support space colonies; sometime down the road it could serve as a stepping stone to outer solar system development. And it is a small planet which would be easy to develop, unlike the giant gas planets.

Aside from that, I think it can wait.

16 posted on 02/26/2002 10:48:04 AM PST by RightWhale
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To: blam
Send a buck. Send the Gore-Sat that's mothballed.

I want to know about this dark planet that Art Bell's recent guests/callers keep talking about.

17 posted on 02/26/2002 11:08:53 AM PST by Calvin Locke
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To: Calvin Locke
Make that "Save a buck"
18 posted on 02/26/2002 11:09:55 AM PST by Calvin Locke
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To: Calvin Locke
dark planet

As a guess it is the Sitchin planet, the 12th planet, which some people think --for whatever reason-- is on its way to earth once again. Our masters making a swing past the colony to see how their creation is doing.

19 posted on 02/26/2002 11:13:28 AM PST by RightWhale
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To: RightWhale
The funding is in the federal budget. Pretty much a done deal.

The only "done deal" is $ 30M in the current year budget. There is NO request for additional money in FY 03 from the administration. $ 30 M sounds like a lot, but it's about 1/20th the amount needed to fly this thing. Congress may try to add money, but it'll take at least $150 M in '03 to get the project where it ought to be; that's not an easy "add-on" for pork. It's likely that this thing is finished.

20 posted on 02/26/2002 11:30:30 AM PST by Cincinatus
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