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New Horizons Spacecraft Wakes Up To Prepare For Historic Flyby of Distant Object (space.com)

Posted by BeauHD on from the to-boldly-go-where-no-one-has-gone-before dept.

jwhyche writes: The New Horizons space probe has been in hibernation mode since Dec. 21. On June 5th, the spacecraft exited hibernation mode and began preparing for its next encounter. The spacecraft is currently 3.7 billion miles from Earth and will be spending the next few months preparing for its flyby of a small Kuiper Belt object nicknamed Ultima Thule (officially 2014 MU69). The craft is expected to pass by Ultima Thule during the New Year's holiday.

6 of 36 comments (clear)

  1. Actual press release by tonique · · Score: 4, Informative

    A link to to the actual New Horizons site should be informative as well.

  2. Just slept for five months by MichaelSmith · · Score: 3, Funny

    And its twelve years old.

    Yep, becoming a teenager.

    --
    http://michaelsmith.id.au
  3. Why now by hackertourist · · Score: 4, Informative

    To answer the inevitable question, "why wake it up now when the flyby is 6 months from now",

    - the team needs time to check the spacecraft
    - it needs to upload new software for the encounter, at speeds in the region of 1 kbit/s
    - the spacecraft needs to do some observations to help in navigation. The targeted KBO is called 2014 MU69 because it was discovered in 2014, meaning we have very little data to derive its orbit from. Pre-flyby observations help finetune the flyby distance (has to be as close as possible to get good photos).

    Over the next three days, the mission team will collect navigation tracking data (using signals from the Deep Space Network) and send the first of many commands to New Horizons' onboard computers to begin preparations for the Ultima flyby; lasting about two months, those flyby preparations include memory updates, Kuiper Belt science data retrieval, and a series of subsystem and science-instrument checkouts. In August, the team will command New Horizons to begin making distant observations of Ultima, images that will help the team refine the spacecraft's course to fly by the object.

    1. Re:Why now by Anonymous Coward · · Score: 3, Interesting

      You never compress code in those situations. Data maybe.
      It's a bit misleading to say uploading new software. You never upload *new* software on flight hardware in the sense that most people would understand it. The risk of anything going wrong is just too large, a lot of things are hardcoded and data transmission speeds are crap.
      It's usually just uploading a different set of commands that are handled onboard the existing software. So in terms of data size its very small.
      In this case it probably concerns more the science instruments, so it's more like telling different instruments to switch modes and configurations to adapt for the new environment.

  4. New Horizons Data Rates by dtmos · · Score: 2

    One of the system requirements of the New Horizons telecommunication system is a minimum post-encounter end-of-playback data rate of 600 bps. From "The RF Telecommunications System for the New Horizons Mission to Pluto":

    A 16 bit control register is used to provide 65532 possible downlink data rates, from a minimum of 6.3578 bps to a maximum of 104.167 kbps. The relation between control word setting n and the data rate is BitRate = (5 MHz) / (12 * (n + 1)) where n is between 3 and 65536, inclusive. The fine spacing of data rates about the expected post-encounter playback rate of 1 kbps gives the mission operations team a great deal of flexibility to take advantage of late improvements in the space segment and ground segment system performance.

    The "improvements" to which they refer would likely be in coding techniques developed after the New Horizons design was frozen (or after its last software update) or, less likely, improvements in the noise temperature or antenna gain of NASA's Deep Space Network receiving system.

    So they expect to have a data rate of approximately 1 kbps, want at least 600 bps, and can use down to 6.3578 bps if absolutely necessary.

  5. Re:So by Waffle+Iron · · Score: 3, Interesting

    I'm going to be generous and—rather than ask for a citation I know doesn't exist—assume that you were trying to be funny.

    He may be alluding to the first transatlantic cable (1850s), where they didn't fully understand electromagnetic signal propagation, and they damaged the cable by overdriving it with high voltage in an attempt to improve reception. Before it completely failed, the bandwidth became so low that it took a whole day to send a single short message.

    Any individual bit sent was much shorter, of course, but the signal-to-noise ratio was so bad that it took a long time to decipher each bit. So in practical terms, it wasn't really anywhere close to the speed of light.