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New Horizons


r4pt0r

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Is it weird to ask all kinds of relativistic questions when you see a timestamp like that? What was the time on board? How did the signals 'perceive' time?

Well, they have to synchronize clocks for their communications to have any success, do they not?

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Here's my assumption: they're coming from the sun side where pluto is nicely lit (maybe not that strong, but still). Now they're on the dark side. I don't know how much of the sensors depend on reflected light but if they do there's not a lot of data to gather for them right now.

It sounded to me like the signal they received was just a quick "everything is still working, here's the amount of data I've collected so far, now I'm going to go back to collecting data for the next few hours" prior to the first scheduled transmission (the "New York Times" packet) tomorrow morning. It doesn't sound like it's going to be transmitting continuously for the next year.

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Get some sleep! :) Great day, all around.

Thanks, but no worries for me. I'm not part of the pluto team. Its a big lab, and i work in another area. But I have a few friends in the Space sector (which itself is pretty big and does more than just NH) and a few of us hung around with them - you know, waiting it out, till we knew it had made it.

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That is pretty much what I meant from the start: if further data is going to be collected, might it not be prudent to collect as much as you can before you are a long way off? Apparently NASA thought they are away far enough already.

I think you're not getting that all the "data" leading up to the intercept was just NASA playing with their toy (okay, testing systems and verifying things are working). All of that data was erased for the flyby where they pushed the sensors into overdrive and filled it up to the brim.

NASA didn't give a crap about the photos they've been feeding us, the real interest are the shots we haven't seen yet, the gigabytes of information they collected during the brief moments when the flyby occurred.

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I think you're not getting that all the "data" leading up to the intercept was just NASA playing with their toy (okay, testing systems and verifying things are working). All of that data was erased for the flyby where they pushed the sensors into overdrive and filled it up to the brim.

NASA didn't give a crap about the photos they've been feeding us, the real interest are the shots we haven't seen yet, the gigabytes of information they collected during the brief moments when the flyby occurred.

I really doubt that. It would mean NH was designed with too small amount of solid state memory storage. Remember that this was all planned. Every sequence of turn and imaging and scanning, it was all planned.

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Yep, it would make no sense at all to send a probe with not enough memory storage. The only reason why they would suspend communications in this time is because they need the energy for all the instruments rather then transmitting data which needs lots of power.

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Yep, it would make no sense at all to send a probe with not enough memory storage. The only reason why they would suspend communications in this time is because they need the energy for all the instruments rather then transmitting data which needs lots of power.

If you mean the "no transmission during flyby": During an interview a scienctist said that they were unable to point the dish towards earth and all the instruments towards Pluto at the same time.

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If you mean the "no transmission during flyby": During an interview a scienctist said that they were unable to point the dish towards earth and all the instruments towards Pluto at the same time.

Yes. When you travel for so much time in deep space you want as few moving parts as possible, so the antenna and all the instruments are almost 100% fixed. Can't point the antenna towards Earth and instruments towards Pluto at the same time. I'm guessing there would also be a few energy problems with that, but the main thing is in fact the s/c orientation.

- - - Updated - - -

Just found some interesting stats on PT1, PT2 and PT3, the 3 KBOs which could be visited by New Horizons (actually PT2 has already been discarded)

Keep in mind New Horizons has 130 m/s left of Delta-V

pts.png

Paper

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I really doubt that. It would mean NH was designed with too small amount of solid state memory storage. Remember that this was all planned. Every sequence of turn and imaging and scanning, it was all planned.

Well, this is sort of true, but ...

In reality, think about it this way. The probe that is flying past pluto today (or was yesterday actually) was launched ~10 years ago. - 2005. It was designed and specced years before that. Call it ~1998 or so. Any equipment flying on it, most especially the computer systems and solid state memory - had to be space certified - in other words, been tested in space previously and believed to have a high likelyhood of surviving a 10 year space flight with little chance of degradation to performance from many factors, not the least of which is damage due to high energy particles. Generally, that means that the stuff that is put into spacecraft is about 10 years older than state of the art at design time, in order to have had enough time and data to meet space certification. I wasn't part of the design team, and I haven't seen the documents, but its a good bet that the computer systems and memory associated with them that passed pluto in 2015 were early 1990s technology. This would be the first time that solid state drives were really available, and of course the MB/weight were atrocious compared to what we view as good today.

This is a long way of saying that any spacecraft is designed with compromises - weight vs. capability / reliability vs. capability (and lets not forget cost) - so yes: it was all planned, but no: they didn't launch with as much memory as they would like, they launched with as much as they could afford.

- - - Updated - - -

Well, this is sort of true, but ...

In reality, think about it this way. The probe that is flying past pluto today (or was yesterday actually) was launched ~10 years ago. - 2005. It was designed and specced years before that. Call it ~1998 or so. Any equipment flying on it, most especially the computer systems and solid state memory - had to be space certified - in other words, been tested in space previously and believed to have a high likelyhood of surviving a 10 year space flight with little chance of degradation to performance from many factors, not the least of which is damage due to high energy particles. Generally, that means that the stuff that is put into spacecraft is about 10 years older than state of the art at design time, in order to have had enough time and data to meet space certification. I wasn't part of the design team, and I haven't seen the documents, but its a good bet that the computer systems and memory associated with them that passed pluto in 2015 were early 1990s technology. This would be the first time that solid state drives were really available, and of course the MB/weight were atrocious compared to what we view as good today.

This is a long way of saying that any spacecraft is designed with compromises - weight vs. capability / reliability vs. capability (and lets not forget cost) - so yes: it was all planned, but no: they didn't launch with as much memory as they would like, they launched with as much as they could afford.

so did a bit of digging. Just to answer more completely, NH launched with two 8 gig modules of solid state memory. (one primary, one backup). pretty good considering when it went up.

-Seyv

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I think you're not getting that all the "data" leading up to the intercept was just NASA playing with their toy (okay, testing systems and verifying things are working). All of that data was erased for the flyby where they pushed the sensors into overdrive and filled it up to the brim.

NASA didn't give a crap about the photos they've been feeding us, the real interest are the shots we haven't seen yet, the gigabytes of information they collected during the brief moments when the flyby occurred.

Actually they explained during one of the presentations that the images we got up to the actual flyby are part of contingency data; they'd have something if things would go wrong during the flyby.

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If you mean the "no transmission during flyby": During an interview a scienctist said that they were unable to point the dish towards earth and all the instruments towards Pluto at the same time.
Yes. When you travel for so much time in deep space you want as few moving parts as possible, so the antenna and all the instruments are almost 100% fixed. Can't point the antenna towards Earth and instruments towards Pluto at the same time. I'm guessing there would also be a few energy problems with that, but the main thing is in fact the s/c orientation.

Well that is not all, NH has 4 antennas in total, the large HGA and the medium MGA are dishes and need to be pointed towards earth to be able to communicate. However NH also has 2 additional LGA which could keep communication with Earth all the time no matter in which position. But even the low gain antennas are disabled during the flyby and the only reason for this is the energy consumption. The RTG delivers aprox. 200W of power and there is no battery buffer, so when they activate all the instruments and the computer/storage they consume all the available power.

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It looks like Canberra is receiving a signal from NH according to JPL's DSN Now site. I hope that means they are receiving data now. Is there a page that shows a schedule of when different spacecraft will have time on each of the DSN antennas?

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New Horizons wasn't actually designed to collect so much data. Since its launch new moons have been discovered, and obviously that's a bit of extra science. Plus, as they said yesterday, they have discovered dozens of ways their instruments could collect even more data (for example after the Jupiter flyby they discovered Alice could also be used as a detector of some kind of particle I forget). Shouldn't make a huge difference, but still, it's more than they expected back in 2006 and when they were building it.

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