Summarized, would it be correct to say;
In terms of distance, New Horizons was half-way in February 2010… in terms of travel time, New Horizons would be half-way in March 2011?

That's correct on all counts- showing Jupiter's disk *and* the unresolved Galilean satellites (which are that much fainter relative to Jupiter because of the fairly high phase angle) requires really pushing the dynamic range of the camera, which also really brings out the background noise and scattered light artifacts around Jupiter itself.

Also as Gordan says, the camera is optimized for much longer exposures. The technical reason for this is that LORRI has no shutter, so the image continues to be exposed while it is being read out, a process that takes 20 milliseconds and moves the image across the CCD. The raw image consists of the 9 msec true image superposed on a 20 msec image where the target is smeared across the width of the frame- this "readout smear" image is removed in software, but the noise that it adds to the image can't be removed. At Pluto, where the true image will typically have an exposure time of 100 msec or more, the noise contribution from the readout smear is smaller.

John

We'll be half way in travel time on 17 Oct 2010.

-Alan

Now there's an expression of faith in Microsoft products.... think it'll work
5 years from now (assuming you consider its function satisfactory even now)?

Digs at MS aside, there is a serious issue for long outer solar system
missions in knowledge retention in people, and software maintenance:
I remember ESA used Displaywrite 4 when I started working on Huygens...
and I think there were some ADA compilers used for the descent imager
software that were no longer supported circa 2003 when the code had to
be patched

Software (and, actually) hardware sustainment is a universal problem.

I'll get my hat.

Thank-you john_s, I didn't realise that the smear was quite so bad! Do you just use a naive subtraction or deconvolution type approach (or something a bit more advanced)? Looks like some sort of denoising approach might be necessary to help get rid of the smear removal artefacts. Might be an interesting project to play around with in my spare time

I've been porting my Outlook data from release to release since it was internal-only back in 1996, so that's 14 years so far. I don't think another 5 is really pushing it.

A friend sent me some C code (not Microsoft stuff) from almost 30 years ago. I compiled and ran it with only minor problems. And don't even get started on the huge bulk of algorithms in Fortran that are pushing fifty years old now.

With today's virtual machine technology, I think the right approach would be to create a virtual machine image containing the OS, compiler, version-control, and other tools used to develop a mission and then keep copies of that VM indefinitely. When you get new hardware, you just need to be sure it still runs your old VMs. (That's a much, much lower hurdle than running all your apps.)

That assumes you don't NEED an upgraded version of the OS or tools, of course. It still makes sense to stick with widely-used technologies, since those are most likely to be updated with an eye towards backwards-compatibility.

--Greg

Disclaimer: I left Microsoft a couple of years ago, after over 14 years there. Their opinions don't necessarily represent me. :-)

Readout smear isn't bad at all at Pluto, because the "real" images have much longer exposures than the superposed "readout smear image", and the algorithm that's used to remove the smeared part of the image is accurate if no part of the image is saturated (though I can't tell you the actual algorithm offhand), and leaves behind no artifacts except a little additional random noise. If part of the image is saturated we have to resort to cruder subtraction methods, using regions of dark sky in the image to determine the smear contribution.

John

What would the one-way signal delay time be at Pluto, which will always be 5 billion kilometers away?

Pluto's orbit is elliptical.

"Light takes between from 4.1 hours and 6.8 hours to travel from the Sun to Pluto" depending on the orbital position of Pluto.

You could find out for yourself with some very simple maths. you could even find the exact distance to Pluto using http://space.jpl.nasa.gov on any date and time.

If it's 5,000,000,000km - and light is, roughly, 300,000km/sec. Thus about 16,700 seconds - or about 4.63 hrs.

Could someone elaborate on Pluto's position in relation to the ecliptic, as the dwarfplanet orbits at a 17° angle to the plane.
Is the NH encounter timed so Pluto-Charon pass through the ecliptic in order to get a better change to dive further into the outer regions of the solar system towards other KBOs and possibly SDOs?

http://pluto.jhuapl.edu/mission/whereis_nh.php

Seek and ye shall find!

Solar System Simulator graphic

Distance and Light Travel Time Calculator.

I don't think they had any choice about it. At the time of the encounter, Pluto will have a moderately high, southern declination (something like 10 deg, if memory serves.) They definitely wanted to get to Pluto before it was too far from the Sun, and Pluto is in a Kozai resonance, so its declination and distance from the Sun are highly correlated. A side effect of this, by the way, is that some New Horizons and Cassini scientists may end up arguing with each other about the use of the Canberra 70-m DSN station, since it is by far the best for a spacecraft in the southern sky. Since there is an overlap in the science teams, some scientists will get to argue with themselves about this.