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New Horizons, Pluto and the Kuiper belt
djellison
post Feb 19 2005, 10:54 PM
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'Good' News isnt sexy. If the US media is anything like the UK media - then they love talking a story up ( NH getting funding to go ahead ) then smashing it to pieces. They do it with sports stars, governmental projects, anything

And they'll never set the record straight when things pan out properly.

Doug
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cIclops
post Feb 20 2005, 08:00 AM
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QUOTE (DEChengst @ Feb 19 2005, 09:15 PM)
Why does bad news always make big headlines and the good news somehow just doesn't get mentioned ?

Recall the old adage "Never let the truth get in the way of a good story" :>


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cIclops
post Feb 20 2005, 08:16 AM
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QUOTE (Alan Stern @ Feb 19 2005, 09:09 PM)
The RTG and the necessary fuel are both in good shape.  Previous problems resolved.
All needed fuel is now ready. We expect 190 W or a tad more at Pluto in mid-2015.
The s/c requires ~165W, so there is a healthy margin. The launch approval process
has begun, and will take the remainder of the year to complete.

Welcome to our humble forum Alan, pull up a keyboard and make yourself comfortable smile.gif

What great news, NH is all gassed up and raring to go! I've got so many questions I hardly know where to start.

Okay how about with these two:

Given the 190+tad Watts at Pluto, how far out will that take NH?

Does NH have a really minimal power mode that will allow very low data rates (seconds per bit perhaps) for super extended missions?

Certificate No. 1125

324 days to launch window


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Guest_Sunspot_*
post Feb 20 2005, 12:35 PM
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Short article on New Horizons at the Planetary Society website:

http://www.planetary.org/pluto_75/pluto_ne...ons_190205.html
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Alan Stern
post Feb 20 2005, 03:10 PM
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Given the 190+tad Watts at Pluto, how far out will that take NH?

This depends on when we launch in the 2006 window or the backup 2007
window because the exit velocity varies with launch date. The basic answer
is that predicts show that we have sufficient power to run out to 2025, which
corresponds to ~50-60 AU if all goes well.

Does NH have a really minimal power mode that will allow very low data rates (seconds per bit perhaps) for super extended missions?

We have data rate capabilities down to 10 bps, but using them doesn't extend
the lifetime or range estimates above. That said, there may be some heroic
things one could do if all's well to extend further. We have't looked at that.
Our job is to keep our eye on the Pluto ball, and there's more than enough
to keep us busy with that.
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DEChengst
post Feb 20 2005, 04:15 PM
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About the 768 bit/sec datarate at Pluto: Is this what can be achieved with the current DSN or with planned upgrades to the DSN ? Because if it can be guaranteed with the current DSN, it's not unlikely that DSN will get better recievers in the coming 10 years that would allow for higher datarates cool.gif


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Alan Stern
post Feb 20 2005, 09:40 PM
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Yes, the 768 bps is for the current system-- 70 m antennas at a range of 33 AU.
If their are improvements in DSN that are compatable with our telecom design, we could take advantage of them. .. That aside, you might be interested to know that it looks like our actual as-tested telecom performance is 1.5-2x better than the 768 bps spec performance, which is of course good news-- for those of us interested in faster downlinks.

-Alan
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cIclops
post Feb 21 2005, 08:56 AM
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Thank you for such fast and succinct replies Alan. It must be my turn now to ask the next question smile.gif

I'm curious about NH's software and its level of autonomy but I've been unable to find any description of it other than it runs on Mongoose V R3000 processors. The ten year flight gives plenty of time to design powerful new heuristics to optimize data collection during encounters.

To what extent does the NH software process follow the Cassini code while you fly model?


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alan
post Feb 21 2005, 09:22 AM
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QUOTE (DEChengst @ Feb 19 2005, 09:15 PM)
QUOTE (Alan Stern @ Feb 19 2005, 09:09 PM)
The RTG and the necessary fuel are both in good shape.  Previous problems resolved. All needed fuel is now ready. We expect 190 W or a tad more at Pluto in mid-2015. The s/c requires ~165W, so there is a healthy margin.

Why does bad news always make big headlines and the good news somehow just doesn't get mentioned ? They scare the hell out off you by telling telling New Horizons may fly late or not at all due to lack of plutonium, but once the problems are solved the press somehow keeps silent. Thanks for the update and making me sleep a little bit better tonight wink.gif

The shortage of plutonium was caused by an alleged security problem at one of the labs. A couple of CDs with classified information on them went missing and everything stopped while they reviewed security protocols etc. I read recently that the CDs that were susposedly missing never existed and all the fuss was over an inventory problem. mad.gif
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cIclops
post Feb 21 2005, 09:50 AM
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QUOTE (alan @ Feb 21 2005, 09:22 AM)
The shortage of plutonium was caused by an alleged security problem at one of the labs. A couple of CDs with classified information on them went missing and everything stopped while they reviewed security protocols etc.  I read recently that the CDs that were susposedly missing never existed and all the fuss was over an inventory problem.

It's unlikely that whatever is made public about highly classified labs is true and should be taken with a very small pinch of Uranium salt smile.gif


323 days to opening of primary launch window


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Guest_BruceMoomaw_*
post Feb 21 2005, 10:09 AM
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The Feb. 17 "Nature" has a news item on the revelation that the missing disks never existed -- and if it's a cover story, it's an oddly counterproductive one. According to the magazine, most of Los Alamos' scientists are in an absolute fury over all this, and some of them are quitting.
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DEChengst
post Feb 21 2005, 05:27 PM
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QUOTE (Alan Stern @ Feb 20 2005, 09:40 PM)
You might be interested to know that it looks like our actual as-tested telecom performance is 1.5-2x better than the 768 bps spec performance, which is of course good news-- for those of us interested in faster downlinks.

Aren't we all interested in faster downlinks ? When we got our first modem 1200 bps was considered fast. A lot of BBSes would only support 300 bps. Some were running on older hardware and would do 300/75 bps max. It took quite a while to download even one floppy to your 8088 box. Today my ADSL line got upgraded to 8192/1024 Kbps. Downloaded a 50 MB Mars panorama in about a minute. Imagine how long that would have taken to download on one of those 300 bps BSSes. Having memories of using 300 bps the logical conclusion is that I'm getting old wink.gif


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Guest_Guest_*
post Feb 22 2005, 12:36 AM
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The autonomy software is a rule-based system being put in place pre-flight. We do not expect to upgrtade it unless bugs occur that are not revealed in the (extensive) ground testing.

IThe system is based on the autonomy engine APL did for MESSENGER, with some improvements.
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cIclops
post Feb 22 2005, 06:48 AM
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QUOTE (Guest @ Feb 22 2005, 12:36 AM)
The autonomy software is a rule-based system being put in place pre-flight. We do not expect to upgrtade it unless bugs occur that are not revealed in  the (extensive) ground testing.

IThe system is based on the autonomy engine APL did for MESSENGER, with some improvements.

Thanks for the details.

Here is a description of the APL rule based autonomy system: PDF file

Ten years is a very long time in the software universe, there may be other better approaches such as neural networks available by 2015. To make the most intelligent use of spacecraft resources during encounter is it possible to significantly enhance the software?


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Alan Stern
post Feb 22 2005, 01:09 PM
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QUOTE (cIclops @ Feb 22 2005, 06:48 AM)
Ten years is a very long time in the software universe, there may be other better approaches such as neural networks available by 2015. To make the most intelligent use of spacecraft resources during encounter is it possible to significantly enhance the software?


It's not about doing what is best in terms of systems efficiency, it's about minimizing risk. The saying we use is that "better is the enemy of good enough." There is also that pesky detail of having limited budgets, so aerospace geeks and PIs love to say,
"If it ain't broke, don't fix it." Enough said.
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