Exactly. You have to consider the entire system (flight hardware, flight software, data rate, DSN time, ground hardware, ground software, funding, and most of all priorities) to determine feasibility. NH's overwhelming priority for the next year or more is to download encounter data, which will require the spacecraft to be both inertially and systemically stable.

After that, the top priority will be to reconfigure for the 2014 MU69 encounter which almost certainly will require flight software updates as well as one or more course corrections as the object's orbit and size estimates are refined.

I don't see much room in any of that for a KBO search even if doing so was a lot easier than it seems to be. The risk of causing unexpected problems with the spacecraft thereby seems like enough justification to not even consider this. At best, this would be a post-MU69 encounter activity and as Doug pointed out any search it could do would still be inferior to those that can be done with Earth and near-Earth based assets; doesn't sound like something that's likely to be funded, nor even something that would be of interest to the NH team, quite frankly.

I am sorry that I have offended our experts and moderators by asking stupid questions.

I mean no disrespect by asking "why" or "how".

I do not question the competence of those with actual experience in spacecraft design and operation.

I'm asking stupid questions, not because I question your opinions and conclusions;
but because I am trying to better understand the facts and what led you to those opinions and conclusions.

I owe you an apology, please accept it.

Hey, man...no need for that. Valid questions, good discussion, everybody learned something. It's all good.

One item about streaks... Remember every CCD in deep space receives artifacts along with the actual image. The longer you leave a CCD like LORRI open, the more they become excellent particle radiation detectors, covering up real data.

Protons from the Sun will be a problem. Cosmic rays (heavy ions) from outside of the solar system are also a problem. Longer images = more opportunities for particles to interact with the detector. This interaction results in streaks but streaks that may not be in the direction of a posigrade orbit around the Sun, will likely be a straight line and may cover up something that is real in the frame.

As pointed out, it doesn't matter for the next year as data "rains" down on Earth from the Pluto encounter. Since the MU69 encounter is relatively new, I haven't heard whether the NH team plans to put the spacecraft back into hibernation after the data download to conserve funding, as they did out to Pluto. Maybe Alan can give us a hint, next time he stops by?

Funding is one of those consumables that has to be conserved, just like propellant. Ground operations folks like to eat and have a place to live and therefore have to be paid. Hibernation means a much smaller ground team for those years.

Andy

I was looking at NH's trajectory in celestia, figure where it will be when the Pluto downlink is done in late 2016. Appears NH may be within ~15 au of a KBO named Ixion.
Roughly a year later within ~15 au of a KBO named Quaoar. Both should appear against a dark sky, with no bright stars or nebula nearby.

Interesting question is whether that is close enough to get spectrum and light curve data?
The KBOs are 19th magnitude, when viewed from earth
NH's camera specs are 17th magnitude at 9.9 seconds exposure.

So, KBO distance from Earth is 40 au and NH is 15 au, so ~2.5x closer, or roughly 7x brighter.
If the exposure time is stretched to 3x longer, then that's about 21 times as bright.
Hmm, sounds like that just might work?

Edit - fun factoid-
New Horizons is spin stabilized at 5 rpm.
Holding down the pitch key(s) in celestia spins you around at about 5 rpm.

Well, one way to look at it, is that at 1 rotation per 12 seconds, and a .29 degree FOV,
a point source takes ~9.6 milliseconds to cross the FOV of Lorri.
NH specifications say exposure times down to 1 millisecond are possible.

A real quick proof of concept, The crosshairs in celestia appear to be about 1 degree across.
There notch in the center of the crosshairs is roughly 1/3 or 1/4 of that, so ballpark .3 degrees.
Bump the stars up to highest, 15.1 magnitude, render them as points.
Center the crosshairs on the known KBOs, and they are usually the only thing in frame.
So, my piano-tuner estimate is that yes, it ought to be possible to image a target
and generally have no, or only a few stars brighter than 15th magnitude in frame.

But what could the spinning Lorri actually see?
Eh, Lorri can image 17.5th magnitude with 9.9 second exposures.
So, 9.6 milliseconds, and you're getting 1/1000th of the light, which is, 2.5^6.5.
So, ballpark estimate, something must be 11th magnitude to be imaged on a single pass.
To get 17th magnitude, take the same image 1,000 times (~3 hours, 20 minutes) and stack them.

More to the point, for every one large known KBO, there's a hundred large unknown KBOs out there and millions of small ones.

But I really don't want to comment in any more depth than this because my last reply on this topic was deleted (still trying to figure out just what was wrong with it) and I don't want it to happen again.

A perspective I won't forget, thanks!

There seems to be a disconnect between what is within the cone of NH's flight path,
versus what is resolvable with NH's cameras like Lorri. The finding fly by targets paper does the hard math, but it is about fly by candidates, not about whether KBO's are detectable.

In spin mode, my back-of-the-envelope calculations are that NH's lorri needs 11th magnitude to detect. That means even "bright" 24th magnitude KBOs probably wouldn't not be detected. That's a difference of 13 orders of visual magnitude, so KBOs have to be 2.5^13 brighter eh, 149,000 time brighter for NH to see. But since NH is closer and visual magnitude follows inverse square law, what is 24th mag from earth, would be 11th relative to NH once it was 40 au / 386 or ~ 1/10 au. Basically a spinning NH would have to be at the KBO to see it.

Ok, I think I have an answer.
There should be about 6 KBOs within the remaining NH flight cone.
But to find them you'd have to stop and take an image every 2/3 of an AU to find them.

There's another table, projected #of targets, with a statistical # of KBOs along NH's flight path. It predicts the number of targets by magnitude, for different assumptions.
Predictions are 1 target >26.5 mag, 2.5 >27th, ~5 >27.5 and ~11 >28th.
breaking that into bands, I get:
1 brighter than 26.5,
1.5 between 26.5 and 27th,
2.5 between 27th and 27.5 and
6 between 27.5 and 28th.

Three targets were found for NH, which is a good match to the statistical estimates.
Current target is at 43.4 au and is 26.8 magnitude.
Based on those estimate there may be 8 other targets in the "flight cone" from 30-50 AU
that are between 27th and 28th magnitude. Figure NH is around 1/4 of the way through that distance, so about 6 KBOs to find.

Lorri specifications are 17.5 magnitude 9.9 seconds exposure.
The maximum exposure of 29.9 seconds lets in >2.5 times the light, lets say 19th magnitude.
So, looking for 28 magnitude KBO with a telescope that sees 19th magnitude ~9 orders of magnitude. That's 2.5^9 so objects need to appear 3815 times brighter, or be closer.
Closer follows inverse square law, square root of 3815 is ~62,
so 1/62nd the distance of 42 au is 2/3rd of an AU.
For 27th magnitude (2.5 KBOs predicted) that's 8 orders, should become visible at around 1 au.

Oh, flightcone is a ~0.5 deg half-angle cone through the Kuiper Belt for accessible targets.
NH field of view is .29 degree, so you'd need to stop and take a montage of photos to cover the .5 degree cone. Yes, the cone widens are you head deeper into the kuiper belt, so you might
need 2x2 at 35 out to 40 au, then 3x3 out 45 au, etc.

Wait a minute.
We expect 11 KBOs at random to be in a .5 degree radius "flight cone" 20 AU long,
That flight cone is .5 degrees half angle, stretches from 30 to 50 AU
That's a cone 20 AU long, 1 degrees wide eh, ~.64 cubic AU in volume.
If there are 11 KBOs in .64 cubic AU, that's ~17 KBOs per cubic AU.

What area of space can NH search?
NH has about 15 AU left to travel through the main Kuiper belt.
Figure the faintest KBOs at 28th magnitude are visible at 2/3 AU.
That's ¶ x Radius^2 x length=3.14 x .67 AU x 15 AU ~ 21 cubic AU.
At 17 KBOs per cubit AU, that's ~357 KBOs.

Again, I'm sort of afraid to write a reply out of fear that my posts are just going to be deleted. So as much as I'd like to, I'm not going to risk responding to that.

I will however bring up an earlier topic (and hope it's not a deletable thing as well): James Webb. I was a bit curious as to how useful JWST would be for finding KBOs in NH's flight path - aka, how good it is at finding very dim KBOs in a very narrow cone. I found a 2008 paper, "Future Surveys of the Kuiper Belt" which touched briefly on just that:



Sounds promising for the particular task at hand - there should be vast numbers of KBOs of that size. But again, it wouldn't be available until some point after the next flyby.

Any news yet on when the first burn is due?

According to THIS article which gives a transcript of Alan Stern talking about New Horizons at the recent ScienceWriters2015 meeting, they will be firing the engines to retarget in the direction of 2014MU69 in just two weeks!

Just food for thought, when distances of ~15 AU are being discussed… that only puts New Horizons 2 or 3 times closer to the object than Earth is from the object. Hubble, or even Cassini (Saturn and Pluto happen to be near conjunction), could obtain better data in a case like that.

Well, I think there's an interest in NH getting different data, light curves, and viewing dim KBO's against a dark sky, whereas Hubble and Earth scopes looking for dim KBO's are looking at the milky way as the backdrop.

Why would the Milky Way be more of a problem for earth scopes and Hubble than NH? The plane of the Milky Way is at a steep angle (very roughly 50 degrees) to the ecliptic, so KBO's wouldn't tend to appear against the Milky Way from earth.