EPOXI comet flyby timeline

By Phil Plait | November 3, 2010 2:00 pm

wise_hartley2Emily Lakdawalla at The Planetary Society blog has posted a timeline of the events on Thursday, leading up to and after the spacecraft EPOXI (née Deep Impact) flies past the comet Hartley 2, currently gracing the northern skies.

Deep Impact will fly past the nucleus of the comet on November 4, 2010 at about 14:50 UTC. It will pass at the insanely close distance of 700 kilometers (420 miles), where it will see objects as small as just a few meters across on the comet’s surface. This won’t be the highest resolution a spacecraft has seen a comet nucleus, but it’ll still be pretty impressive. We have precious few closeup images of comets, so this is bound to be a terrific event. Stay tuned here, and check with Emily’s blog during the event; she’s bound to have the most up-to-date info and pictures!

Related posts:

Three views to a comet
EPOXI sticks like glue to extrasolar planets
Ten things you don’t know about comets

CATEGORIZED UNDER: Astronomy, Cool stuff

Comments (11)

  1. So EPOXI is sticking to that comet like glue? (Hey, somebody had to say it).

  2. Romeo, Phil already beat you to that joke. :) See the list of “Related Posts”.

  3. Jeff

    keep us posted,

    was this a spontaneous visit to Hartley the second? Wasn’t that comet just discovered. It seems awfully weird that the brightest comet in a few years , a few months later epoxi is doing a flyby??

    And no, I’m not an HBer, so no implications. nor am I a comet cultist who committed suicide after one of those comets got bright, such bunk. Just asking a straightforward question. In fact, I hate when my students ask loaded questions, I ask them to only ask honest ones.

  4. Oli

    I’d love to see that comet. Sadly, all I have seen for the last couple of months is clouds. I can hardly even remember what the sun or the moon looks like…

  5. KC

    Jeff, I’m not sure why you think its weird. This is the first visit to Hartley 2, the second comet visit for the EPOXI spacecraft (aka Deep Impact) which visited Comet Tempel in 2005. Comet Hartley 2 was discovered in 1986 – not recently. This encounter was planned well in advance when a visit to Comet Boethin was canceled (that comet may have broken up).

  6. Jeff

    5- thanks, that explains it. I knew it was a bright comet this year, so I assumed it was discovered this year, but it was discovered long ago. So what was coincidental was that the mission to Hartley was planed well in advance, but also brightened up so much.

    What I meant by “weird” was that other than , of course, Halley, I’ve never known of a really bright comet like this coinciding so close in time to a planned comet close encounter, that is very unique in my experience at least

  7. Messier Tidy Upper

    Marvellous news & I’m looking forward to it immensely wishing for the best for this doughty little spaceprobe. :-) 8)

    EPOXI countdown clock to comet encounter # 2 for Hartley 2 here :


    Rendezvous with Hartley is now just 2 hours,12 mintes and 11 secs away. :-)

    More info. on Comet Hartley 2 is here :


    via Wikipedia.

    (because links to further info. are compulsory. 😉 )

    Off topic but worth noting : Discovery‘s final launch and the penultimate Shuttle ever has been delayed due to poor weather :

    Managers will delay Discovery’s launch for 24 hours due to weather. Mission managers will meet tomorrow at 5 a.m. to reevaluate the weather conditions. Friday’s launch attempt would be at 3:04 p.m. EDT.

    Source : http://www.nasa.gov/mission_pages/shuttle/main/index.html

    The countdown there stands at T-minus 1 day, 6 hours, 58 minutes 5 secs at time of typing.

    Delayed again & again & again .. [Anthropomorphising on.] It’s as if Discovery knows its the last time of all & so just doesn’t want to go. Sigh. :-(

    [/anthropomorphising off.]


    … the spacecraft EPOXI (née Deep Impact) ..

    I could be mistaken here, but my understanding is that the spacecraft *itself* is still called Deep Impact although the *mission* has been renamed EPOXI.

    I dunno why really – it seems a bit uneccessarily confusing and pointless to me esp. if they really have renamed the spaceprobe itself. :-(

    (Not that it, being an in animate object, could care less, natch, but still.)

    I would have thought just calling it Deep Impact ‘extended mission’ would’ve been fine and much better.

  8. Messier Tidy Upper

    PS. On the bright side [of the latest weather related delay for the Discovery‘s launch] at least now I can stay up for the Deep Impact flyby of Hartley-2 without worrying about missing out on too much extra sleep for having to get up early in order to catch the penultimate shuttle lift off online. :-)

    PPS. Thankyou NASA TV. 😀

  9. Messier Tidy Upper

    Success! :-)

    About an hour after closest approach & we have five great medium resolution images from the fly-by.

    See :


    with more high resolution images to follow. :-)

  10. Messier Tidy Upper

    Yes! Deep Impact / EPOXI has suceeded! :-)

    Hartley 2 is a small, active, peanut shaped – but solid – cometary nucelus with a number of jets. More active, smaller than any comet than seen so far. (Halley is more active and much larger.)

    In a nice touch, they also had the discoverer Malcolm Hartley (an Aussie! 😉 ) present in the room as the first pictures came through as well – & we got to see the discovery image taken from Siding Spring then the very latest and best images. :-)

    Coverage still continuing as I type. EPOXI page with images so far is linked & awaiting moderation.


    Now T- 1 day, 3 hours, 30 minutes and zero seconds before the scheduled launch for Discovery.


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