Nasa's New Horizons: Final flyby commands given to distant probe | Hacker News Reader

Nasa's New Horizons: Final flyby commands given to distant probe

bbc.com

152 pointsgpvos72 comments

The final command for this part of the mission as no further communications would be possible until the flyby has been complete and the probe can reorient itself to call back home, it would take 18 months to get the data back from New Horizons as its current data rate is 1kbp/s or 2 with induced spin.

This isn’t the end of the mission for NH.

Thanks for clarifying that. The velocity of this probe is really astounding!

I’m currently reading this book about the history of the DSN.

https://www.amazon.com/Uplink-Downlink-History-Space-Network...

Fascinating stuff. I wonder how they will manage the priority of getting that data back over the next two years? Timeshareing on the DSN has been a problem since the early 60’s.

I’m not sure they can even get all of the data back.

The probe has limited data storage capacity and even more limited bandwidth to send it back to earth.

I’m guessing they have a protocol to prioritize data from different instruments as well as prioritize data purging if there is an opportunity to look at something more interesting before everything could be sent back home.

It can be a heartbreaking process for some of the teams for sure.

My best bet is that they get some initial indication of what data was collected then prioritize based on what they think is the most interesting or valuable from what was collected.

They were still retrieving data form the original Pluto flyby as this one was planned I’m not sure if they even got all the data from pluto yet.

> purging if there is an opportunity to look at something more interesting before everything could be sent back home.

This is not a risk as, with high probability, there is nothing else on their trajectory they will be able to look at for the 18-month downlink time.

> I’m not sure if they even got all the data from pluto yet.

They did. It's true that they have limited data storage space, but they have had plenty of time to download the entire data set from Pluto.

https://futurism.com/it-took-15-months-but-all-of-new-horizo...

I believe the major constraint is how much data they can take during the short flyby time, not storage space or downlink time.

Well it sorta both yes the flybys at this point are so short that the amount of data they collect is limited but they still collect GB’s of data and the up line data rate will likely drop even further as the probe goes further.

It’s still astonishing to me that they can get 1kbp/s with s 1.5m dish antenna pointed at a target 0.29281 arc minutes in size.

This is the equivalent of pissing into your toilet form orbit.

But heck now the FCC can claim that broadband coverage has been expanded up to the Kuiper Belt.

Re: I'm guessing they have a protocol to prioritize data from different instruments as well as prioritize data purging if there is an opportunity to look at something more interesting before everything could be sent back home.

I suspect if a new nearby target were discovered, they may have to send back just thumbnails and summarized/compressed data, review the summaries back on Earth, and only request the more promising full images and data snippets.

I just hope they already have such compression/summarizing software onboard because sending significant new software that far can be a bear. I wonder if they planned for such a "rush job" scenario?

It’s main CPU is a 12mhz MIPS processor I don’t think they do any complex software analysis on board.

Summarizing doesn't necessarily require complex algorithms. For example, a 64x64 pixel image can be averaged into a 16x16 image, and/or a highly compressed JPEG. And data streams can maybe average 1-second intervals into 30-second intervals. You can get a little fancier by only averaging intervals that don't vary much, using standard statistical algorithms (including "cheap" approximations to save CPU). A lot of times cameras and instruments will be pointing at empty space because they error on the side of capturing unknown petributions/objects. If you are not looking for faint moons etc., you can mostly ignore those "dark areas", at least in a "data emergency".

And remember, the summarized versions are used to narrow down the set of full data sets returned. Thus, if something looks unusual in the summaries, the full set of that segment is requested from the probe. If there is a need to rush, it's a matter of narrowing down which parts of the data you want to send back in full.

The instruments are turned off until they are needed they cannot be used when the space craft is spinning which is required for it to transmit data to earth which is what it does most of the time the flyby lasts minutes at the most, the data takes over a year to transmit.

Also even if it didn’t need to be spun the instruments would be turned off to save power, the probe has no instruments that could detect any objects without a preplanned flyby.

I don't see how this is related to the above. It seems there's context confusion. I meant data processing (summarizing) of existing STORED data so that humans can review and decide on what to keep (fully download) and what to discard/delete so that there's enough storage for an upcoming new target.

After passing a target, there's boatloads of data to send back. If a new target means there's not enough time to download it ALL before storage is needed for the new target, then decisions have to be made about what to fully send back and what to skip and/or only send summarized/compressed versions of. This has very little to do with instrument activation; it's a "between targets" process.

Even if they cannot get all the data back, I suppose they could do a preliminary analysis onboard and decide what to send back.

It is, in a very broad sense, the same problem we have at the LHC. There is just too much data taken for the available storage and bandwidth.

Is that the effective payload data rate after error correction has been applied or the actual transmitted bit rate meaning that the payload rate is much less? I've read that NH uses a 1/6 Turbo code for forward error correction. If true, that would imply that the transmitted data rate is actually 5 to 10 kbps or the payload rate (after e.c.) is 200-400 bps.

That’s the data rate afaik

http://pluto.jhuapl.edu/Mission/Spacecraft/Data-Collection.p...

https://en.m.wikipedia.org/wiki/New_Horizons#Telecommunicati...

Pluto encounter data rate was 2000 bp/s but that is with the spin, I’m guessing it’s lower now since it’s well past Pluto.

I can’t find the link to the interview which had a bit more information about it now, but I don’t think they refer to the payload data rate.

New Horizons can't use many of its scientific instruments and cameras in spin mode. Spin mode gyroscopically stabilizes it so that its main antenna can be pointed more precisely, allowing a higher data rate. Thus, I suspect they won't want to enter spin mode until it's no longer doing any photographic or scientific observations of Thule. Therefore, data packets will be slow in the days before and after encounter because they want to still aim instruments; but this makes antenna pointing less precise. New Horizons can't chew gum and talk at the same time :-)

Again they won’t plan missions in this manner, in the rare event that they’ll need to override data they’ll have a clear protocol sending a summary in this case would be a waste of bandwidth.

Both your statements are not clear to me. There still seems to be some unstated assumption that is confusing one or both of us.

>This isn’t the end of the mission for NH.

At ~1:30 in the video interview with Alan Stern he says they have ~20 years of power in the RTG and 'plenty of fuel' to get around. Sounds like there could be a lot of science yet to come!!

The Hubble scope had to spend many hours to find this target, basically taking "before" and "after" images to find changes: dots moving against the background stars seen via subtracting the pixels values of before and after. Once they find rough candidates, they take more pics to narrow down their orbits. Any new targets will be further away and thus probably dimmer to Hubble than Thule. Also, New Horizons only has so much fuel to change direction. Its room to operate is a very narrow cone, kind of like a long lopsided straw. It will be challenging finding new objects to visit. I wish they didn't have to depend on Hubble so much.

Time to send a telescope into distant orbit?

You mean send a Telescope to the Kuiper Belt? I believe resources would be better spent sending a probe to one or few of the bigger Kuiper Belt objects, such as Eris and Sedna. New Horizon's "target problem" is rather specific to that probe. Pluto was its primary mission. Other bodies were considered a bonus, and the probe doesn't have enough fuel to target the bigger (known) objects. Perhaps that was a mistake; but many of these were discovered after the probe was budgeted.

There would be no reason to do that. Putting telescope into distant orbit will not make it easier to observe anything except for the thing you are orbiting.

The problem with kuiper belt objects is not that they are far away but that there is not much light reflected from them. The belt is huge, and if you put say Hubble in there you have no guarantee you would see anything.

Putting space observatory is costly project, money are better spent by putting it in Earth orbit as it is much cheaper to put it there and possible to service while in orbit. If history teaches us anything it is that being able to service the telescope in orbit is very important for getting as much bang for the buck as possible.

Re: There would be no reason to do that.

In general, probably; BUT I'd qualify that to say it depends on the mission. As I mentioned nearby, visiting the bigger known Kuiper objects seems a bigger priority than finding new smaller ones (and finding them is better done near Earth).

However, if something unusual were found at Thule such that a mission to study lots of smaller Kuiper objects were deemed warranted (like being made of gold or clear signs of life), then a probe with a relatively big telescope could be sent into the Kuiper Belt to hunt such objects in its approximate vicinity. That may still be cheaper than building larger-than-Hubble scopes near Earth to guide New-Horizons-like probes. But the math on that may depend how sparse smaller Kuiper objects are.

That probe would be worse than a Hubble like telescope at an earth or near SOL orbit.

Firstly due to their relative small size their angular size wouldn’t make much difference at those distances.

Secondly you essentially limiting your search envelope to a small section of the belt as most of it would be further away form the telescope in the belt than from earth.

And lastly you can launch a much bigger telescope to a near earth orbit than to the belt and you can also get the data much more rapidly so you can actually search for candidates in hours not in months and readjust the telescope as you see fit.

Is there any reason to think of an array of telescopes, like the VLA? Like, multiple smaller telescopes scattered at large distances? Or is that too difficult to coordinate?

This has a lot of sense and shouldn't be too difficult to coordinate. This has already been tested by LISA Pathfinder (https://en.wikipedia.org/wiki/LISA_Pathfinder) and proven to be feasible. Still, the reson here to get something far away from Earth as a general is not to have closer observation point but to have large distance between array nodes.

Considering the size of the Kuiper belt it wouldn’t make much difference if you observe if form earth orbit or from within an orbit in the belt.

Interestingly, we'll solve this problem just about when it won't matter anymore for New Horizons. In the 2020s the Large Synoptic Survey Telescope will come online, which will (among other things) catalog tens of thousands of KBOs/TNOs.

Isn't TESS kind of built to do the same thing? Wide field analysis? Presumably it's looking for dimming rather than relative motion, but that seems more like a software issue than a hardware one?

Not exactly. TESS monitors bright objects. It uses actually quite small telescopes (only 10cm aperture or so), but the it has 4 such telescopes and uses very wide fields of view to monitor a large number of stars continuously. To see KBOs/TNOs requires more light gathering power.

Ah! OK, makes sense. Thank you!

Their biggest problem atm isn’t time but speed, they have fuel but they can only do limited course correction as they don’t have that much specific impulse available to them.

So they need to find interesting things on their way bwfore they fly off.

Sounds like there could be a lot of science yet to come!!

From Wiki: at Pluto's distance, a rate of approximately 1 kbit/s per transmitter is expected. Besides the low data rate, Pluto's distance also causes a latency of about 4.5 hours (one-way).

Scientists have a lot more patience than I do!

I wonder if they watch their planet porn arrive one scan line at a time.

There's a lovely photo of scientists manually painting the scan lines coming in from Mariner 4, like a paint by numbers picture

https://www.nasa.gov/multimedia/imagegallery/image_feature_1...

I can tell you stories about the days of 300 baud dial-up modems.

When 256 colors was good enough...

For high res displays. The rest of us got by on 16 colors.

And 110 baud before that (Model 33 Teletype).

In a lot of ways, science and patience are the same thing.

Not in all ways. But a lot of them.

“Plenty of fuel” is a PR spin. They have enough fuel for an additional flyby, but it has to be an object that is pretty much along their path anyway, or far enough out that a little tiny nudge will correct their course over a good portion of that 20 years. Hopefully such an object will be discovered once they start looking.

‘... before Ultima Thule encounter” should be added to title.

I'm really quite excited about this. I don't know if I'd just completely missed it, or if they it hadn't had much publicity in the mainstream press, but it was a pleasant surprise to read about yesterday!

Well the government shutdown means that there's been no NASA PR for this.

Fortunately, the Johns Hopkins University is posting some news and materials because they operate part of the mission. Here is where they will post raw images:

http://pluto.jhuapl.edu/soc/UltimaThule-Encounter/

More links: http://pluto.jhuapl.edu/News-Center/

Anyone else hoping this rock is a bracewell probe? Im so sick of mars rovers. It is refreshing for a probe to be discovering something totally new. This rock (or maybe group of rocks) was only a handful of pixels last week. Next week it could be almost anything.

I’m holding out hope it’s the skull from a dead Celestial.

Why not? Every space scientist would give thier entire career, every dollar ever spent by nasa, for even a hint of such a discovery. When gravity wave detectors were first turned on every scifi fan was hoping we would see warp drives buzzing around. That sense of wonder, of unlimited possibility, is the real reason we explore such distant places.

My hope is that if there are whole new levels of science that haven't yet even glimpsed, then the aliens using that science are so far advanced that we have no hope of viewing the footprints they leave across the galaxy. Or perhaps that they have a very strict prime-directive-style zero-interference policy that they've built something that protects us from seeing anything out of the ordinary until we reach a certain level. It may be that such esoteric or advanced sciences can really mess up your local star system if handled poorly, so they want to keep immature hands away from the stove, so to speak.

Neither of those possibilities really mean that we should be doing anything different regarding our peering into the cosmos. There's certainly wonders already in our view that are beyond anything we can really comprehend.

> Every space scientist would give thier entire career, every dollar ever spent by nasa, for even a hint of such a discovery.

Not everyone (case in point: me). We're not all obsessed with the search for ET.

But if you did find something, you wouldnt drop everything else? Finding any serious evidence of ET would bring the entire scientific world to a hault.

Intelligent aliens? Yes, of course. But there are many lines of evidence which makes it extraordinarily unlikely and almost no one is looking for little green men out there.

What people are searching for, and orienting our exploration programmes around, is the possibility of a second genesis and non-intelligent, probably microbial life on other worlds. That, frankly, is uninteresting to me as both a humanist and a scientist, compared with what we could be working on instead. It’s a gigantic, PR driven self-perpetuating hype machine that eats up budget and resources that could have been put to better uses.

Asked for my opinion, I gave it, and get down voted.. not expecting upvotes, but why the down votes?

Not sure why it would hover around out there and wait for us to come to it. (Also, it would be a hell of a coincidence if we happened to hit the only probe out there.)

For the same reason they buried a monolith on the moon.

The Moon makes sense - we've only got one, it's a much smaller search area, and iirc, it started actively broadcasting after a certain point.

The outer solar system is a huge search area.

It's the difference between your mailman leaving a package on your porch, or somewhere in Canada.

I mean, ok, but then Mars will prolly just want to pull some sketchy shit so they can use it to further their terraforming, and what if some maniac Earther decides Mars is too much of a threat, and wants to turn it on them? And oh man do you want the OPA having access to alien tech?

Its kind of neat watching The Deep Space Network - https://eyes.nasa.gov/dsn/dsn.html

Nearly every dish is receiving or sending to NHPC.

Exciting! Sounds like they will get reasonable pictures (but the object is quite small).

190 Watts is now equivalent to 20 lightbulbs, not 3 like the article suggests :) since we've moved away from the incandescent ones.

We're going to need to compare electricity usage against some new appliance. How about GPUs :P

The probe takes as much power as one high end GPU.

"This probe can mine up to one bitcoin a week!"

At the distance they will be at closest approach, Ultima Thule will extend through as much of the sky as the full moon does to us on Earth. This is actually not all that large, but anyone who has looked at the moon through a telescope can attest to the phenomenal detail that is possible, and New Horizons is equipped with some high calibre telescopic instruments.

it's leaving the solar system but no golden record.

instead, it has a quarter, a flag, human ashes and a cd-rom disc without a drive or a codec.

srsly?

Well, if they are going to ship a codec, they will have to make a choice for the CPU architecture or even have to ship a CPU. Then they might have to ship some batteries as well

And of course, a full source code and the cross-compiler. On a CD-ROM.

Lol. But seriously, the irony is CD-ROM's degrade to completely unusable within a century due to disc rot. A CD-ROM made with gold and completely encapsulated in an extremely stable enamel might work. Then, leaving universal instructions as to how to use said CD-ROM is important, rather than arrogantly presumptive anthropocentrism.

A CD-ROM rots fast due to the deyes, but what about a normal pressed CD of aluminum? Those should be pretty stable. I have only seen those destroyed with sunlight.

Do you think NASA burned a 24x CD-ROM from their PC and added it to New Horizons?

CD-ROM? As in ISO 9660 data disc? That's going to be a hell of a challenge to reverse engineer for alien civilizations.

If they're anything like us, they will be curious enough about who created it to try to extract whatever data they can from it.

If we found the alien equivalent of such a device it would be kept in a clean room and sampled and imaged until we could completely understand it. We would also try to extract whatever insights we could from the designers of such a device in case they ever decide to stop by.

We're not intentionally obfuscating the information on the disc. We've just made a lot of design choices based on the technologies available to us. We're hoping that any civilization that's out there can recognize those intentional choices by very careful analysis of the device. After all we're the type of civilization that scans areas of the sky looking for data in the background. Why wouldn't there be a people like us somewhere in the infinite cosmos?

Please read here: http://expreso.co.cr/centaurs/essays/uranians.html - So called "Cupido" at 40.998 AU may be the same as "Ultima Thule" object/planet. Research is done by Alfred Witte, based on Sun vibrational field which is creating standing scalar waves and forming the physical planets.

"may be"?

How about, no, it isn't. The astrology link you pointed to says:

> 1- they are completely idealized points moving in perfect circles around the sun without any physical acceleration except the Sun's, i.e.

> 2- they are subject only to the influence of the Sun and are not affected by the gravitational interactions of other large bodies.

This is not true of Ultima Thule, with a perihelion of 42.721 AU and aphelion of 46.442 AU. Its semi-major axis is nearly 10% larger than the mean solar distance of 40.998 you quoted.

The text goes on to insist that "things in Astrology work very well even though they do not or cannot physically exist", so why is there a need to have it exist?

Furthermore, user "Juan" points out the problems in the analysis, such as "it is obvious that the more asteroids you put into the equation, the more likely you will find one that resembles in its motion the orbit at least of Cupido". And the suggestion that 2000 KL4 matches Cupido.

How do we tell which is "really" Cupido?

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