Re: {MPML} Chang'e 4 launch schedule?

From: Bill Gray via Seesat-l <seesat-l_at_satobs.org>
Date: Sun, 9 Dec 2018 09:51:28 -0500
    Two bits of good news.  As Scott Tilley has already posted,
he's gotten the radio signal from Chang'e 4,  and it looks to be
about 10 arcminutes south of prediction.  That's about right for
the object to go under the moon's south pole before orbit insertion.
(My thanks to Cees Bassa;  he gave me some good thoughts on how to
"guess" a likely orbit based on knowing the liftoff time and the
time of arrival at the moon.)

    And this morning,  we have object A10azqL on the NEOCP,  which
looks to be the booster for this mission.  It's lagging Chang'e
4,  and will reach the moon about a day later,  miss,  and go into
roughly a 37-day orbit.  Pseudo-MPEC with orbital elements at
various epochs,  further comments,  and a link to TLEs at

https://www.projectpluto.com/pluto/mpecs/18103b.htm

    Further astrometry for this object would be quite welcome (and
probably challenging).  Then again,  I didn't expect to see any
data for this object until after it went past the moon;  it's
brighter than I'd have expected at so low an elongation.

-- Bill

On 08/12/2018 18.58, tme_at_asteroidinitiatives.com [mpml] wrote:
> The lander-3rd stage separation
> 
> https://twitter.com/AJ_FI/status/1071440711248158720
> 
> Starts 1:05 in
> 
> https://www.weibo.com/6528178851/H6iRDzAfH?from=page_1005056528178851_profile&wvr=6&mod=weibotime&type=comment
> 
> Marshall
> 
> 
> On 2018-12-08 12:35, Bill Gray pluto_at_projectpluto.com [mpml] wrote:
>> On 08/12/2018 09.45, tme_at_asteroidinitiatives.com [mpml] wrote:
>>> On their Weibo account, China Aerospace Science and Technology
>>> Corporation (CASC) confirmed that #ChangE4 has successfully separated
>>> from the upper stage and is now in lunar injection orbit, with perigee
>>> at 200 km and apogee at ~420,000 km.
>>> https://www.weibo.com/5386897742/H6cRnxOac?from=page_1006065386897742_profile&wvr=6&mod=weibotime
>>> …
>>>
>>> https://twitter.com/Yeqzids/status/1071244045614075904
>>
>>      And also stated that it'll enter orbit around the moon at
>> 15:00 UTC on December 11.  That really constrains the possible
>> orbit,  and shows that my solution was far off,  by about 15
>> degrees.  We're now looking at an elongation from the sun of
>> about 45 degrees,  so I don't really expect optical confirmation.
>> (At least,  not until after the booster passes the moon and is
>> seen sometime later.  This will be similar to the orbits I got,
>> in hindsight,  for Chang'es 2 and 3 on their way to the moon :
>> I used the astrometry from well after the lunar flyby to figure
>> out the earth/moon leg.)
>>
>>      I've updated the TLEs (same URL as before).  The new orbit
>> hits the moon at 15:00 UTC on the 11th,  because I don't know
>> what the actual planned orbit is.  Assuming it does a close
>> flyby,  my trajectory will be a little more than a quarter
>> degree in error at that point,  making it a near-miss.
>>
>> -- Bill
>>
>>
>> ------------------------------------
>> Posted by: Bill Gray <pluto_at_projectpluto.com>
>> ------------------------------------
>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>> Posts to this list or information found within may be freely used,
>> with the stipulation that MPML and the originating author are cited as
>> the source of the information.
>> ------------------------------------
>>
>> Yahoo Groups Links
>>
>>
>>
> 
> 
> ------------------------------------
> Posted by: tme_at_asteroidinitiatives.com
> ------------------------------------
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Posts to this list or information found within may be freely used, with the stipulation that MPML and the originating author are cited as the source of the information.
> ------------------------------------
> 
> Yahoo Groups Links
> 
> <*> To visit your group on the web, go to:
>      http://groups.yahoo.com/group/mpml/
> 
> <*> Your email settings:
>      Individual Email | Traditional
> 
> <*> To change settings online go to:
>      http://groups.yahoo.com/group/mpml/join
>      (Yahoo! ID required)
> 
> <*> To change settings via email:
>      mpml-digest_at_yahoogroups.com
>      mpml-fullfeatured_at_yahoogroups.com
> 
> <*> To unsubscribe from this group, send an email to:
>      mpml-unsubscribe_at_yahoogroups.com
> 
> <*> Your use of Yahoo Groups is subject to:
>      https://info.yahoo.com/legal/us/yahoo/utos/terms/
> 
_______________________________________________
Seesat-l mailing list
http://mailman.satobs.org/mailman/listinfo/seesat-l
Received on Sun Dec 09 2018 - 08:52:18 UTC

This archive was generated by hypermail 2.3.0 : Sun Dec 09 2018 - 14:52:18 UTC