
New Horizons’ first hi-res imagery of Ultima Thule - mbrundle
http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20190102
======
mbrundle
I find it truly amazing that New Horizons was able to take photos of a 20 mile
object whilst flying past at ~8 miles/sec - that’s an incredibly small space
and time window within which to capture the images. Does anyone know how NASA
manages to pilot spacecraft with this level of precision? What kind of
engineering processes do you need to enable this?

~~~
lisper
> photos of a 20 mile object whilst flying past at ~8 miles/sec

Not to detract at all from the astonishing technical achievement, but that's
the wrong comparison. You can see the ISS with your naked eye, and it's a <1
mile object flying past at 4.8 miles/sec. The right comparison is with the
distance at which this photo was taken: 18,000 miles, or about half an hour
from closest approach.

Actually, the right comparison is of the closest approach distance (~2000
miles) with the distance from earth (4,000,000,000 miles). That's like
launching a missile from Los Angeles to New York and hitting your target to
within a meter.

~~~
jdmichal
To be fair, while that's an accurate representation of the distances, it's not
accurate of the difficulty. They don't have to deal with unpredictable
atmosphere. There's reasons laser-guided missiles are about 1-2 meters-ish of
accuracy with constant guidance, while we can basically fire-and-forget
spacecraft to 4 billion miles away.

~~~
lisper
No, that's actually not true. Hitting Ultima-Thule is much harder. For
starters, just figuring out where U-T actually _is_ is very difficult. The
observations we have only constrain two of its three degrees of orbital
freedom. The third has to be inferred via orbital mechanics. Likewise,
figuring out where the spacecraft is is also non-trivial. By way of contrast,
figuring out where you are relative to New York to within a meter of accuracy
is, nowadays, a simple matter of switching on your GPS receiver. (Even without
GPS, all you need is inertial guidance that is stable for half an hour or so.
That's much easier to achieve.)

Finally, there are unpredictable orbital disturbances. N-H uses thrusters for
attitude control, whose effect on the trajectory is not entirely predictable.
(c.f.
[https://en.wikipedia.org/wiki/Pioneer_anomaly](https://en.wikipedia.org/wiki/Pioneer_anomaly),
which was only detectable because, although Pioneer had thrusters, they were
turned off for long periods of time).

I know these things because I used to work at JPL. There are entire teams
dedicated to spacecraft navigation. The stuff they do will blow your mind.

~~~
rbanffy
I wonder how much would it cost to build a GPS-like network for the whole
solar-system...

The good thing is that, for such a thing to be really useful, we'd have to
invent better propulsion systems which would, in turn, make the network much
cheaper to build.

~~~
toomuchtodo
Pulsars can be used to arrive at celestial positioning accurate to ±5 km.
There is a test rig on the ISS that has validated this. No need to build human
made beacons when the universe has so graciously provided us with them.

[https://en.m.wikipedia.org/wiki/X-ray_pulsar-
based_navigatio...](https://en.m.wikipedia.org/wiki/X-ray_pulsar-
based_navigation)

~~~
rbanffy
They plan to get within 1km, which is quite impressive for one system alone.
Thanks for the pointer (after reading it, I remember having read about NICER,
but didn't remember the precision they got)

~~~
lisper
> quite impressive

Especially when you consider how far away the "beacons" are.

~~~
PaulHoule
The far away beacons make the math easier. Also those beacons are awfully
bright.

------
Rooster61
Kind of sucks that this is the big first picture that is being published. The
LORRI, while an impressive piece of hardware in and of itself, is not built
for high detail, close-in shots (although it was used some for the Pluto flyby
closeups). That's the job of the Ralph telescope on-board the spacecraft.

It's a neat picture, but I fear that any subsequent pictures will have less
impact on the public, as many laymen will say "Meh, saw that the other day on
<insert_news_site>. Old news".

I'm really looking forward to the spectacular shots we will get from the
close-in imager. New Horizons will be MUCH closer to this object than it was
Pluto, so it should really get some fantastic shots of the surface features.

For comparison, just check out the wikipedia pages. They show a pretty solid
contrast of the capabilities/uses of the two devices:

[https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imag...](https://en.wikipedia.org/wiki/Long_Range_Reconnaissance_Imager)

[https://en.wikipedia.org/wiki/Ralph_(New_Horizons)](https://en.wikipedia.org/wiki/Ralph_\(New_Horizons\))

------
quakeguy
"The team says that the two spheres likely joined as early as 99 percent of
the way back to the formation of the solar system, colliding no faster than
two cars in a fender-bender."

Welded together by gravity, i'm really in awe seeing the, by far, weakest
power so lovely at work.

~~~
robotrout
So, two masses were close enough in relative velocity and vector, that one of
them didn't careen off the other one, and instead, allowed the weakest of all
known forces to bond them together as they hurtled at high velocity through
space.

This object(s) seem statistically unlikely to me. I'm not saying it's
artificial. That would be even more unlikely, by orders of magnitude. Just
saying "Wow!".

~~~
hughes
As this is the first Kuiper Belt Object we've visited, it's hard to draw much
about the statistics of the thing.

~~~
tempestn
What's exciting to me is, both the first interstellar object we've observed
visiting our solar system (Oumuamua) and the first Kuiper Belt Object we've
visited have been "unusual". That strongly suggests to me that the unusual is
more usual than we would have suspected, which means there's probably a great
deal of opportunity to increase our understanding of the universe!

~~~
JoeSmithson
They deliberately picked targets that seemed unusual from initial readings.

~~~
atq2119
Oumuamua was literally the _only_ extra-solar object known. There was nothing
to be picked.

Similarly for Ultima Thule. They _may_ have been able to find a different
target, but it was very difficult to find any target at all in the first place
(lots of Kuiper belt objects are known; the difficulty was finding one that
could be reached by New Horizons). See this Twitter thread that was linked
elsewhere:
[https://twitter.com/Alex_Parker/status/1077986070128668674](https://twitter.com/Alex_Parker/status/1077986070128668674)

------
azernik
"hi-res" is relative - this is still about 5 times the feature size that was
actually captured by the LORRI camera. Going to have to wait at least a few
days for the glorious 30m/pixel version.

~~~
Avamander
Some page wrote that it takes more than a year to get every piece of
information about the fly-by.

~~~
SubMachineGhost
Pluto's flyby generated about 8GB of data and it took about 16 months to get
all of it downloaded [1], and this data includes more than just the images,
and i read somewhere that the Ultima Thule flyby will generate about 6GB of
data.

I think the images are the first thing that get downloaded, so it should not
take more than a week to get all high res images.

1 -
[https://en.wikipedia.org/wiki/New_Horizons#Telecommunication...](https://en.wikipedia.org/wiki/New_Horizons#Telecommunications_and_data_handling)

------
jacquesm
Absolutely amazing that they nailed the shape so well based on the occlusion
data. That is super impressive.

~~~
tomerico
From /r/space:

Image of the occultation profile vs actual shape:
[https://i.imgur.com/PNh4nmX.png](https://i.imgur.com/PNh4nmX.png)

Each line is the same star viewed from a different point on Earth. They
arranged for telescopes in a long line North to South to all observe UT at the
same time, just as it was predicted to pass in front of the star. Then they
precisely timed the apparent blinks of the star. The North-South offset meant
the star bisected UT across different sections for each telescope. Then they
just worked out the parallax difference and mapped out the blink times on a
chart to see the silhouette.

~~~
6nf
From that pic it looks like they were able to measure accurately to within
meters of the actual shape at this distance! That is incredible

~~~
jcims
Those streaks in that pic are the path of a star that UT passed. Given they
know the velocity, if they time the period where the light from the star is
occluded, they get a measure of how wide the object is at that elevation.

This is what an occultation looks like:
[https://www.youtube.com/watch?v=7Y_qc8Ifhso](https://www.youtube.com/watch?v=7Y_qc8Ifhso)

Crazy they are able to map a few of those together so precisely to get this
data.

------
jimijazz
This is why I love HN: because I can count to have updated links to content I
care for.

~~~
scrumbledober
I've been getting most of my updates for this from /r/space personally, but I
think that's the main attraction of HN for me. I don't need to curate my own
list of subreddits to get links to content that interests me, because it's all
(mostly) likeminded people on here that are on average interested by the same
kind of stuff as me. I find more new interests on here than I ever could on
reddit looking through my preconceived list of interests.

------
deeths
Here's a link to the press conference slides: [http://pluto.jhuapl.edu/News-
Center/Press-Conferences/index....](http://pluto.jhuapl.edu/News-Center/Press-
Conferences/index.php?page=2019-01-02)

------
high_derivative
Whenever I see these updates, I am reminded of the three body problem trilogy
and its contemplations on space exploration (the parts I enjoyed the most).

Then I get sad because things just take so incredibly long on a stellar scale,
and a human life is so short.

------
entity345
Fantastic.

Just one thing: it would be great if NASA dropped imperial units as main units
in such articles.

~~~
herewulf
I agree. However, the people that are paying for this mission still use
imperial units. Those of them that are paying _the most attention_ would
probably agree with us though.

~~~
perl4ever
US customary units are not imperial units. Many people don't realize, for
instance, that MPG is not comparable between the US and the UK because gallons
are substantially different.

------
skunkworker
That is amazing. It reminds me of a snowman or two snowballs frozen together,
except it's red not white.

As seen in the combined image. [http://pluto.jhuapl.edu/Galleries/Featured-
Images/pics800wid...](http://pluto.jhuapl.edu/Galleries/Featured-
Images/pics800wide/MU69_image_v1%20copy.png)

~~~
rhizome
Comet 67P has a similar shape. I have to wonder if there's something inherent
in these flying rocks that causes them to take a dumbbell shape.

~~~
antonvs
The inherent factor is collision, which is what forms most objects like this.

------
samstave
I personally find it amusing and interesting that the physical object, Ultima
Thule, looks similar to the Virtual Game logo "Ultima"

[https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online...](https://upload.wikimedia.org/wikipedia/en/6/6a/Ultima_Online_-
_The_Second_Age_Coverart.png)

~~~
wallace_f
The nostalgia and innocence and discovry of childhood hit me so hard when I
saw that logo

~~~
mhh__
Quite interested as to by whom/why this was downvoted

~~~
CamperBob2
Forget it, Jake, it's HN

------
ajuc
We only have 2 examples, but both this and the Rosetta mission object were
rubber-duck-shaped. Is this very common?

~~~
InclinedPlane
It's pretty common. Based on radar data about 10-15% of Near Earth asteroids
(larger than 200 meters) are contact binaries (or contact-binary shaped at
least). We don't have enough data on main belt asteroids, trojan asteroids,
and especially TNOs/KBOs to say what the percentages look like for those
populations but it's a fair likelihood that the proportions are at least as
high if not higher among KBOs.

------
ilamont
_The new images — taken from as close as 17,000 miles (27,000 kilometers) on
approach — revealed Ultima Thule as a "contact binary," consisting of two
connected spheres._

Are these common in the asteroid belt or as smaller moons of the outer
planets?

~~~
InclinedPlane
As far as we can tell, they are pretty common. But we haven't visited enough
objects to have firm statistics.

------
monster_group
I highly recommend reading the book Chasing New Horizons by Alan Stern[0]. It
is a great insight into years of work it takes to get a mission like New
Horizons going. It is a very well written book and I could not put it down
until finished.

[0] [https://www.amazon.com/Chasing-New-Horizons-Inside-
Mission/d...](https://www.amazon.com/Chasing-New-Horizons-Inside-
Mission/dp/1250098963/ref=sr_1_1?ie=UTF8&qid=1546475775&sr=8-1&keywords=alan+stern+-+chasing+new+horizons)

~~~
Fuzzwah
Thanks for the recommendation, I was happy to find it available on audible.

------
sizzzzlerz
Pretty decent resolution of a object 27000 km distant. Has anybody seen the
specs on what type of lens NH uses for images like this?

~~~
azernik
This is still nowhere near full resolution - it's at 140 meters per pixel,
whereas the camera got 30 meters per pixel. It's going to take a few days to
download the full images at 1kbps though.

~~~
Avamander
Isn't it 1000baud than 1kbps?

~~~
Tor3
No, "baud" counts number of signal changes per second, which would equal
number of bits per second in the old past (one bit encoded by one signal
change). Ever since modems changed to e.g. quadrature encoding the number of
bits per second would be higher than the baudrate. When somebody talks about
bitrate these days then bps (bits per second) is what they should be using,
not baud.

------
pvaldes
Can't help to mention that several round stones stacked in balance is so
artificial that is an 'universal' sign to mark the path in wild remote areas.
A typical I was here sign.

------
ryanmercer
Um, is that BB-8?

Mimas (and Iaepetus too) really looks like the Death Star and now this thing
looks like BB-8.

Ultima Thule-BB-8 comparison:
[https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg](https://pbs.twimg.com/media/Dv7psG3VYAA8jqa.jpg)

Mimas-Death Star comparison: [https://cdn-
images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9Lorr...](https://cdn-
images-1.medium.com/max/575/1*nUxm5MD_2xO5Y9LorrV8FQ.jpeg)

Iaepetus-Death Star comparison:
[https://cdn.images.express.co.uk/img/dynamic/80/750x445/8290...](https://cdn.images.express.co.uk/img/dynamic/80/750x445/829007.jpg)

------
gravy
Nomenclature:
[https://en.wikipedia.org/wiki/Thule](https://en.wikipedia.org/wiki/Thule)

------
remote_phone
What an astounding feat!

I remember reading they were going to aim for 2000 miles from Ultima Thule,
was the closest approach revised to 18,000 miles?

~~~
JshWright
No, this photo was taken before the closest approach (note the very high sun
angle, there's basically no shadows, so the probe was still inside the orbit
of UT when the photo was taken). It's going to be another month before we see
the closest/highest resolution photos (and years before all the data is
downloaded)

------
sova
It's a snowman with a snowman for a face! (recursive / fractal structures of
the early world) space fern!

------
11thEarlOfMar
Can a human jump off of Ultima Thule?

[https://xkcd.com/681_large/](https://xkcd.com/681_large/)

~~~
gshubert17
Modeling it as two spheres, one 16 km across the other 12 km, with a density
the same as water, its total mass would be about 3*10^15 kg. At a distance of
8 km from the center of mass, the escape velocity [0] would be about 7
meters/second or 16 miles/hour.

But the asymmetry of Ultima Thule means that its gravitational field would be
weird. Not like a sphere at all. So the acceleration of gravity and escape
velocity would vary a lot from place to place.

[0]
[https://en.wikipedia.org/wiki/Escape_velocity](https://en.wikipedia.org/wiki/Escape_velocity)

------
microDude
The lack of craters is interesting.

