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

From: Bill Gray via Seesat-l <>
Date: Sat, 8 Dec 2018 12:35:20 -0500
On 08/12/2018 09.45, [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.
> …

    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
Seesat-l mailing list
Received on Sat Dec 08 2018 - 11:36:10 UTC

This archive was generated by hypermail 2.3.0 : Sat Dec 08 2018 - 17:36:11 UTC