

New Horizons enters safe mode 10 days before Pluto flyby - dandelany
http://www.planetary.org/blogs/emily-lakdawalla/2015/07042044-new-horizons-enters-safe-mode.html

======
dandelany
Alan Stern, the mission's P.I., dispelled rumors that contact had been lost on
the USF forum, saying "Such rumors are untrue. The bird is communicating
nominally."[0]

Also the Deep Space Network[1] page shows an ongoing 1kbps downlink from New
Horizons; during the safe mode event it was at only 9bps. So that's a good
sign! I'm sure they are still panicking a bit about what went wrong, but
hopefully we're out of the woods on this particular anomaly.

[0]
[http://www.unmannedspaceflight.com/index.php?showtopic=8047&...](http://www.unmannedspaceflight.com/index.php?showtopic=8047&st=180)
[1] [http://eyes.nasa.gov/dsn/dsn.html](http://eyes.nasa.gov/dsn/dsn.html)

~~~
tptacek
The idea that we have an ongoing digital comms with something this far from
Earth is completely fascinating to me. Are the encodings used documented
anywhere? All I can find out is that it's X-band, 1kb/s.

~~~
throwaway_yy2Di

        "...encodes block frame data from the spacecraft Command and
        Data Handling (C&DH) system into rate 1/6, CCSDS Turbo-coded
        blocks."
    

[pdf]
[http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%2...](http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf)

~~~
tptacek
Cooooool. ["CCSDS" "standard"] was the Google search I was looking for.

~~~
planteen
If you are curious about reading more, CCSDS is an overloaded term in the
space industry for an onion of different OSI layers that are changing all the
time. My guess is that the telemetry coding standard CCSDS 101.0-B-6 is likely
to have been used on New Horizons. Even though it is now a "historical
document", some new space missions still use it.

Here is a copy:
[http://public.ccsds.org/publications/archive/101x0b6s.pdf](http://public.ccsds.org/publications/archive/101x0b6s.pdf)

------
r721
"NASA’s New Horizons mission is returning to normal science operations after a
July 4 anomaly and remains on track for its July 14 flyby of Pluto.

The investigation into the anomaly that caused New Horizons to enter “safe
mode” on July 4 has concluded that no hardware or software fault occurred on
the spacecraft. The underlying cause of the incident was a hard-to-detect
timing flaw in the spacecraft command sequence that occurred during an
operation to prepare for the close flyby. No similar operations are planned
for the remainder of the Pluto encounter."

[http://www.nasa.gov/nh/new-horizons-plans-july-7-return-
to-n...](http://www.nasa.gov/nh/new-horizons-plans-july-7-return-to-normal-
science-operations)

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robertfw
I wouldn't want to be the one debugging this. Talk about pressure to deliver
and difficult constraints!

~~~
stevewepay
On the contrary, this is where you can really prove that you are worth your
salt. There is no better arena to prove yourself than a real-live production-
down situation.

~~~
kabouseng
It's a shame really, as the engineers fighting the crisis' gets a lot of
attention, but very often those crisis' are caused by themselves.

It is the engineers who's projects run smoothly who is ultimately worth more,
as they can predict and prevent problems before they become a crisis, but get
no recognition for it.

~~~
ende
Yes, this. It reminds me of goalies in hockey, and how people are in awe when
a goalie makes some ridiculous save when in fact the goalie would have never
had to have made such a save if they hadn't been out of position in the first
place. The best goalies are pretty boring to watch.

~~~
JohnBooty
Yes! The Phillies used to have a fan-favorite outfielder who played hard and
often made spectacular catches - but he was actually a pretty bad outfielder;
the reason he made spectacular catches is because he turned routine plays into
adventures.

~~~
speeder
I remembered now how some people considered the US goalie one of the best
world cup players...

The thing is, he was considered one of the best world cup players because the
US defense was so bad, but so bad, that without him US would have ended the
cup losing all games outright.

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nathanb
That is a really well-written article. It explains the problem, explains what
the remediation plans are, and puts a human face on it...while remaining
positive and optimistic.

Looking forward to seeing what the problem turned out to be and how they solve
it!

~~~
dandelany
I highly recommend the planetary.org blogs for space news, especially Emily
Lakdawalla's - they are always excellent.

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zatkin
Does anyone know how good of a quality the cameras are on New Horizons?

~~~
elahd
Wikipedia says the camera is 1024x1024. There are a bunch of other non-optical
sensors on board, as well.

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

~~~
kenrikm
1024x1024 seems rather low res even by 2006 standards. Any idea what
special/expensive/practical reason it needed to be that low res?

~~~
rich90usa
One of the team members had an excellent answer to this question a few days
ago in a Reddit IAmA:
[https://www.reddit.com/r/IAmA/comments/3bnjhe/hi_i_am_alan_s...](https://www.reddit.com/r/IAmA/comments/3bnjhe/hi_i_am_alan_stern_head_of_nasas_new_horizons/csntvhk)

>We’re limited in other ways, weirdly. For example, LORRI, our high resolution
imager, has an 8-inch (20cm) aperture. The diffraction limit (how much an 8”
telescope can magnify) is 3.05 mircorad. which is just over half the size of
single pixel 4.95 microrad. So if we swapped out the current sensor with a
higher res one, we couldn’t do much better because of the laws of physics. A
bigger telescope would solve that problem, but then it would make the
spacecraft heavier, which require more fuel to send to Pluto AND a longer time
to get there, because the spacecraft is more massive. We launched Pluto on the
largest, most powerful rocket available at the time (the Atlas V, with extra
boosters), so again we’re limited by physics: “At the time” doesn’t mean best
ever. The Saturn V rocket, which sent astronauts to the moon, was actually
more powerful.

>More megapixels also means more memory. For example, LORRI images are made up
of a header and then the 1024x1024 array of numbers that make up our image and
go from 0 to 65535 (216). There’s not really a way to make that info smaller
if we went to 2048x2048. We could downlink a compressed version, but we want
the full info eventually.

tl;dr

1\. Between optical physics and balancing different costs to launch mass, it
was the sound engineering choice.

2\. Higher resolution would take even longer to retrieve the captured data.

------
biot

      > and a less educational (but not catastrophic) gap in our
      > light curves for Nix and Hydra.
    

Can someone explain the importance of this? What data would this have
provided?

~~~
greglindahl
You can figure out the rotational period, and get an idea of what the surface
looks like, from a light curve. For example, if half of it reflects a lot more
light than the other half, then you'll see a repeating
brighter/dimmer/brighter/dimmer pattern with a period equaling the rotational
period.

If you have a gap in the light curve, it increases your uncertainty.

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tsieling
Edge. Of. Seat.

~~~
TheOtherHobbes
Edge. Of. Solar System.

~~~
kristofferR
It won't reach the edge of the solar system for many decades, at the very
least (if the edge is defined as interstellar space).

However, it truly won't leave the solar system entirely for at least 30 000
years: [http://spectrum.ieee.org/tech-
talk/aerospace/astrophysics/vo...](http://spectrum.ieee.org/tech-
talk/aerospace/astrophysics/voyager-1-hasnt-really-left-the-solar-system)

~~~
TheOtherHobbes
I was being metaphorical and poetic. :)

------
user
>Not Implemented Tor IP not allowed

Come on! What's the point of blocking tor for them?

