Glitch Halts New Horizons Operations As It Nears Pluto

An anonymous reader writes: NASA says their New Horizons probe suffered a temporary communication breakdown on Saturday, 10 days before it's supposed to fly past Pluto. The mission team is working to restore normal communications. "Full recovery is expected to take from one to several days," NASA wrote in a status report on Saturday. "New Horizons will be temporarily unable to collect science data during that time."

Comments

Oh, PLEASE no...

[jeffb (2.718)]

This has been going so well for such a long time. It will be absolutely heartbreaking if the probe is incapacitated just during the flyby window.

Re:Oh, PLEASE no...

[arielCo]

From T(rather brief)FA:

The “encounter program” includes software to prohibit the very type of automated safe mode that New Horizons executed Saturday afternoon.

“Encounter mode short-circuits the on board intelligent autopilot so that if something goes wrong, instead of calling home for help, which is what most spacecraft do and what New Horizons does during cruise flight, it will just stay on the timeline. It will try to fix the problem, but it will rejoin the timeline because if it ‘went fetal,’ as we say, if it just called home for help, it could miss the flyby,” New Horizons lead scientist Alan Stern told Discovery News before Saturday’s problem.

Re:Oh, PLEASE no...

[arielCo]

The article is too scant. Here's a better one.

The encounter sequence will disable safe mode

[cruff]

Since they only have one shot at the flyby, the New Horizons web site states that the encounter sequence they are uploading will disable the safe mode and instruct the probe to return to the timeline sequence.

From Unmannedspaceflight.com

[Rei]

Link

Steve5304: Rumors that Contact with new horizons has been lost again or was never regained. Unconfirmed

Alan Stern: Such rumors are untrue. The bird is communicating nominally.

Alan Stern is the director of the New Horizons mission. So no worries. :) You can see that two way communication is in progress here at the Canberra dish.

This was a really minor glitch and will have no impact on the mission as a whole. There weren't even any significant observations planned for today.

(As a side note, the closer we get to Pluto and the more we see of it (dark band at the bottom is around the equator), the more it's starting to remind me of an airless Titan :) )

Re:From Unmannedspaceflight.com

[Rei]

Oh and for the record: Stern calls Pluto a planet, and makes some very good arguments.

And I'll add more that he doesn't make (though his are best!): it's ridiculous to call something a "dwarf X" and then say that that doesn't count as an "X". In any other field of science, if you had an "adjective-noun", it would also be classified as a "noun". If you have a dwarf shrew, it's also a shrew. If you have a dwarf fern, it's also a fern. Heck, even in the same field, astronomy, the same rule applies - a dwarf star is also a star.

Under the IAU definition, extrasolar planets aren't planets either. They don't even have a name - they're not anything at all. Not like we'd be able to classify them under the definition without dispatching a spacecraft all the way to each different star system even if they weren't excluded. The IAU definition also claims that they will create a system to establish more dwarf planets - something that clearly has not been done. There hasn't been a new dwarf planet accepted in nearly a decade, despite the fact that we know the sizes of many of them better than already-accepted candidates were known at the time. Quaoar is much bigger than Ceres, and we know it's size down to a mere 5 kilometers margin of error, yet it's not a dwarf planet. The IAU not only made up their ridiculous definition, but they're not even upholding it.

As with pretty much every categorization of object in pretty much every field of science, you need heirarchies and multiple groupings to describe the world. Among planets, we already know of significant diversity, and should only expect it to grow - hence we have terrestrial planets, gas giants, ice giants, hot jupiters, super earths, etc, and yes, dwarf planets - which should be just another category among the significant diversity already out there. Everyone knows a planet when they see it - you don't have to scan its orbit to see if it's "cleared" it, with some still-not-yet-agreed-upon definition of "cleared". If it's large enough to relax into a hydrostatic equilibrium, that's both meaningful, intuitive, and what people expect when they hear the word "planet". By any reasonable definition, our solar system has at least dozens, potentially hundreds of planets. And that should be seen as something to celebrate, not to be appalled about.

Re:From Unmannedspaceflight.com

[K. S. Kyosuke]

And I'll add more that he doesn't make (though his are best!): it's ridiculous to call something a "dwarf X" and then say that that doesn't count as an "X".

Is a toy car actually a car? Is a stuffed animal actually an animal?

Aliens

[jfdavis668]

They don't want us to take pictures of their homeworld.

Re:Memory problem perhaps?

[Rei]

Since this is slashdot, how about pseudocode?

function handle_fault_on_approach()
{
    if (NOTHING_PARTICULARLY_SPECIAL_GOING_ON)
    {
        tell_nasa about_error();
        go_into_safe_mode();
        wait_for_instructions_from_nasa();
    }
    else if (FLYING_BY_PLUTO_RIGHT_NOW)
    {
          tell_nasa about_error();
          wait_to_hear_back_from_nasa = FALSE;
          handle_error_in_a_reasonable_manner_on_your_own();
          get_back_to_gathering_before_you_miss_the_flyby_goddammit();
    }
    else if (FLYING_BY_EARTH)
    {
        dammit_steve();
    }
}

Re:Memory problem perhaps?

[Anonymous Coward]

I don't have any knowledge specific to this project, but I'll give you my interpretation:

The engineers programmed the on-board software to know approximately what the spacecraft should be doing at certain times. New Horizons uses on-board fuel to spin up so that it can more reliably transmit information back to Earth. However, it cannot take pictures while spinning, so it'll have to spin-down. In an "everything's fine" scenario, there will be set times for it to spin up, transmit its data, spin down, capture more data, etc. That's the default timeline.

In previous spacecraft, if something has gone wrong, then the default response was to "stop and wait for further instructions". The idea was that doing "something" could be worse than doing "nothing" and waiting for a human to figure out the best course of action. In other words, it "went fetal".

Pluto is a tad far away, and signals take about 4.5 hours each way. So, a minimum of 9 hours would be required for a response to a problem, not including engineer problem solving and implementation time. That's long enough that the spacecraft may miss the window of ideal picture taking time while waiting for a response, assuming one ever arrives. What it'll likely do in this case is carry on with the mission, and only after it has acquired the flyby data will it call back home and—in Windows parlance—check for updates.

UPDATE: NASA issued a statement - it's good.

[Trax3001BBS]

UPDATE: NASA issued a statement at about 19:30 PT / 22:30 ET July 5 / 02:30 UT July 6 saying that the cause of the safe mode is understood, and that New Horizons will resume science operations on July 7:

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.

“I’m pleased that our mission team quickly identified the problem and assured the health of the spacecraft,” said Jim Green, NASA’s Director of Planetary Science. “Now – with Pluto in our sights – we’re on the verge of returning to normal operations and going for the gold.”

http://www.planetary.org/blogs...