The plans for the Near Encounter Phase of the New Horizons mission have been set in stone since 2009. This week the mission has posted a Playbook that describes all the data that is going to be returned from the Near Encounter Phase -- not only the timing and geometry, but also when it is going to be played back. I also posted an article today about the data that will be played back during the couple of weeks surrounding closest approach. Some of the things I learned while writing that article that are of interest to this forum:

- Not a lot of data is being returned right away (in fact, only 1% gets returned within a week of the flyby).
- After July 20, there will be a long dry spell of no images being returned until the browse data set starts coming down on September 16.
- There will not be much scope for image processing on the data that is being returned near the flyby. There are one or two pairs of images that you can use to make stereo; there are two mosaics; there is one MVIC image for which there is LORRI data returned near enough in time to do colorization.

So it's going to be awesome, but we're also going to have to be patient!

Here is my simulation, using Voyager data, of the LORRI data set that we can expect to have on the ground as of July 20.

Thanks so much for this very informative chart. Is the entire New-Horizons-facing Pluto hemisphere expected to be documented at 0.4km/pix resolution?

Not all of it; there is a 15-footprint mosaic that covers maybe 30% of the visible disk. It's on page 20 of the Playbook I linked to in my post.

Thank you! - Your chart is an excellent overview of the visuals to expect. The playbook has all the info, but your graphic is more digestible for those of us with limited time due to real life constraits (i.e. job and toddlers :-)

That's interesting.....
So, what happens between the time of the 15 highest-rez photos from 77,298km range (p.20) and the time when lower-rez photos are taken before (254,072km range, p.17) and after (359,895km range, p.22) ?
I realize it's all done on July 14, but just how long does it take to get each of the 15 hi-rez photos? ....one might be tempted to think that a more complete hemispheric coverage could be had. Why not ? (Thnx)


Click to view attachment

Primarily because NH's downlink bit-rate at that distance will be around 1kb/sec. Also, imagery obviously won't be the only data coming down and the DSN is a finite resource set that can't be dedicated to NH alone.

Excellent (as always) relevant blog article by Emily here.

A couple of possibilities come to mind, but they all lead back to a mix of too little time and finite storage capacity, and lots of choices on how to spend them.

If you look at the last panel in the figure you attached, you can see that it would take about 3x as many images to cover the expected error ellipse to be sure of getting the whole planet, so 3x as much time and 3x as much data.

This flyby isn't just about imaging, and there are tradeoffs, and I bet the meeting where the 15 images were settled upon was "interesting." Spectroscopy and occultations are also on the list, and those are going to take time and data as well. Since NH has to turn the whole spacecraft to point the instruments, it's not possible to get useful data from all the instruments at the same time. And don't forget the satellites, we want data on those as well.

But my gut tells me it's probably the amount of storage available on the spacecraft that limits the number of images, in the end. Maybe John will chime in to give the real answer.

Jeff

The scarcest resource during the close approach period is time rather than data volume. The spacecraft is designed to do fast turns (up to 1.25 degree/sec) to observe as many targets as possible during the close approach period, but still, each mosaic repointing takes time to settle before we can be sure of a sharp image, time is needed to allocate the memory for recording each set of data, and so on. To answer the specific question, that 15-image Pluto mosaic takes about 20 minutes, and is preceded by Nix observations (hi-res imaging and our best infrared compositional map), and followed by our best infrared compositional map of Charon.

We do get most of the visible disk of Pluto at 0.3 km/pixel with our wide-angle camera MVIC near closest approach, and the whole disk at 0.46 km/pixel with MVIC ten minutes earlier- part of the purpose of that 15-image LORRI mosaic is to provide stereo coverage with the closer MVIC scans.

There were indeed many lively meetings to figure all this out, but they were almost never acrimonious- the entire science team understands the importance of the holistic view of the system that will be provided by all these wonderful overlapping data sets.

John

John is right, the NH sequence planning team for Pluto encounter was exceptionally collegial. The mapping he describes beats the NASA spec requirement for hemispheric mapping of 1 km by a healthy margin, and adds the high-res mosaic. We beat NASA spec for Pluto color mapping and composition mapping by healthy margins too. Amazing data sets are in store!

Shows what I know!

Thanks John and Alan!

Jaro where did you get that image from?

Page 20 of the Observation Playbook.

One note, this is only one of several Observation Playbooks. Others will be posted later on approach, covering other instruments and disciplines beyond just surface mapping by LORRI and MVIC. Stay tuned...

Thanks Alan for letting us "in the conference room!"

Seconded!

Thirded! I haven't been this excited since Voyager 2 encountered Neptune back in 1989!

Thank you for letting us get an insight via your "Observation Playbook".
I can only echo what already been said, that this will indeed be one interesting encounter.

Now I hope you give NH another good workout so she wont sprain a muscle during that intense cosmic ballet performance. =)

I will chime in and say that a major part in New Horizons success thus far has been its team dynamic. I have been amazed, given the competing priorities, at the cooperative spirit with which things are dealt with.

Good morning from Los Angeles! Today marks the beginning of the near encounter phase. NASA TV will air the pre-flyby briefing at 1430 GMT today (13 Jul). Note that all times are subject to change as events unfold.

Please utilize this thread for all New Horizons commentary for the next several days. Here we go!!!

One thing that was being discussed in the last thread, about all of the features that look like "rivers" or "lakes" and the criticism that Pluto's pressure is too low for, say, liquid nitrogen to flow:

Given a triple point pressure of around 12kPa and a solid density of 1027 kg/m^3, 3,2kPa surface pressure, and 0,655m/s^2 pluto surface gravity, Pluto's triple point could be hit underneath as little as 13 meters of nitrogen ice (a bit more, as it would have to have at least a tiny bit of "fluff" to it to float, but that's to be expected). Other ices floating on it such as methane ice could have the same effect. And note that this ice wouldn't be heavily packed due to Pluto's weak gravity, it's the equivalent of less than one meter of nitrogen ice under Earth's gravity. Picture how much a meter of water snow (roughly the same density) packs down on Earth; I'd expect something roughly in the same ballpark - perhaps a situation like arctic sea ice.

Basically, even if there's not liquids flowing on the surface (eutectics or whatnot), there could still be liquids at a shallow depth with a weak ice pack on top of them. And iced-over rivers still flow and move things around.

Thanks for the analysis and the calculations Nafnlaus. That's the relevant problem. I was intersted in peforming that kind of simulations. No need to dig deep for the future lander if you're right.

An interesting thing is that there's a lot of potential liquids and mixtures of liquids / slushes / etc at different (shallow) depths that could be involved here, going through a wide range of dynamic changes as Pluto moves through its seasons. There could be some very complex processes involved in shaping this landscape. I'm sure whatever data comes back, it's going to lead to some very interesting papers down the road

Briefing placard now up on NASA TV.

Starting now....

I have been attempting to measure Pluto's radius from the images that have been obtained in the past few days. I have consistently been getting a values of 1190-1195 km in most cases (1194 km for the latest image). This is close to the radius that SPICE uses (1195 km) but I have seen smaller values elsewhere. Wikipedia gives two values, 1184 km and "1161 km (solid)". The PDS Rings Node Pluto Viewer seems to use a value of 1153 km (selectable in "Field of View" but I'm not completely sure this is the value used to render the Pluto diagrams - I suspect that value may be bigger).

I haven't measured Charon as thoroughly and not in the latest images but I have usually gotten values of 590-600 km. This isn't very far from the SPICE value (605 km).

Pluto's polar cap confirmed as N2 & CH4 ices.

Alan states radius as 1185 km +/- 10.

Saw this on NASA TV, nice to see measurements from the NH team only minutes after I posted my (much more crude) measurements here.

By my count, we now have three different pronunciations of "Charon".

given how it's written in Greek, "kharon" is the correct one

However, the discoverer's wife's name is Charlene. Therefore the pronunciation is similar to Sharon (or Charlene). Wives usually win...

This is absolutely a case where space nerds win out over linguist nerds. The name is only pretending to be Greek. The moon is actually named after the discoverer's wife and is just modified slightly to look like it's mythological, to pass IAU inspection.

Phil

excellent and informative briefing so far I must say

The early, distant detection of ionized nitrogen seems to be the most unexpected thing thus far.

Presser wrapping up.

Does anyone have an estimate of how much of Pluto will not be imaged at all? Either because it's in the dark or just due to the geometry of the encounter?

Best would be a contour map showing resolution in different regions, but just a measure of the invisible amount would be interesting. Same for Charon.

yep, though I expected to see the few LORRI images from yesterday

If I followed Dr. Stern correctly, molecular nitrogen was found five days out of closest approach. Actually at that distance it was ionized nitrogen and is believed to have come from Pluto. The detection was significantly further out than had been expected which *implies* some type of more energetic release mechanism on Pluto. However, the data resolution is too low to really tell at this point.

Also, the methane signature of Pluto's dark regions is significantly lower than that of the polar region.

We all get to add this new information to our image interpretations...

Andy

New version of my Pluto map where I have added the 2015-07-11 22:23 image that was released by the NH team last night if I remember correctly (things are happening fast now!). Longitude 0 is at the left edge of the map.

Click to view attachment

Of course this is probably only hours (or possibly even minutes) from getting completely outdated - and if I want to keep the map up to date I soon need to make a bigger version.

1 million km.

Next media event will be tomorrow 14 Jul/1130 GMT for closest approach, followed by a presser/image release.

Is the media conference going to be uploaded to youtube? I missed it.

Things are happening fast now. As mentioned in a previous briefing, we may not see all the data for awhile. But I'm sure they will put out some images and data this week.

I "accidentally" took a screen grab from a monitor during a live feed from NH Mission Operations today:

Click to view attachment

It sure doesn't look like telemetry data. Although it's too small to be useful, if it is an image of Pluto or Charon, it could be a teaser of the kind of resolution and detail we can soon expect. Personally, I think it could be a close up on Pluto...

Björn's map illustrates how the bright areas to the west in the last image release is probably (at the least) a half-decent preview of the rest of heart feature. The bright stuff here is probably similar to the bright stuff in the rest of it. Judging by lower-resolution maps, there were already solid hints that this part would not be some sort of uniform white, however.

The fact that our closest approach view will include the brightest region and part of the dark region together with other parts in between albedos ,should give us a good representation of all terrain types visualized so far on pluto.

New briefing is up here:

http://www.space-multimedia.nl.eu.org/inde...;catid=1:latest

Just updated the New Horizons image database: http://nchazarra.duckdns.org/db/
Now you can also download the whole records in .csv.

Omnibus New Horizons info post now up at the Planetary Society blog.

I thought it was the NASA TV feed, they were watching themselves on NASA TV, for a few mins.

Good work, and thank you for including all that information for the images. I bet it will useful for the image tweakers on this forum. =)

I guess the leading candidates for the dark stuff are some combination of:

1) Larger hydrocarbons, tholins, maybe the nitriles, etc. seen on Titan.
2) Varied grain sizes that appear darker for physical – rather than chemical – reasons.

There could be very interesting chemistry which will be difficult to interpret from a distance. We still don't know what the composition of the bulk of Titan's surface is, and NH will return a minuscule fraction of the observations of Pluto that Cassini-Huygens returned from Titan. The only compensation is that spectroscopy of Pluto's surface should not be impaired too much by the atmosphere.

Yes, it was on NASA TV, a live feed of Mission Operations after the presentation.

You could sense their excitement, and I don't blame them.

Edit: I just finished watching the replay Req kindly put up on the previous page. Start watching at around 60:42. One of the other staff comes over to check out the image I posted. Looks interesting! There is actually an earlier image to the one I posted if anyone wants to try to grab it.