Re: Object L or object H? (Re: BY O 040216)

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 2 Apr 2016 19:52:43 +0200
Op 2-4-2016 om 18:52 schreef Ted Molczan via Seesat-l:
> Marco Langbroek wrote:
>
>>> The orbit of object 16012L / 41442 is the same as that attributed to Hitomi in the 17 TLEs
>> with ID 16012A / 41337 from
>>> epoch 16086.39579725 through 16091.92327283.
>>
>>> USSTRATCOM's TLEs for Hitomi (16012A / 41337) from 16086.39579725 through 16091.92327283,
>> were for the orbit of one of
>>> the pieces of debris, which has since been reassigned to 16012L / 41442.
>>
>>
>> Ted,
>>
>> May I offer the alternative suggestion that the initial "A" orbits might
>> actually be object H, not L?
>>
>> L fits the new "A" better in terms of RAAN, but in most other elements (arg of
>> perigee, MA, Mean Motion, inc, a) and in actual orbital position relative to the
>> "new" A-object (and hence pass time), the H object seems to fit better imo.
>
> Propagating the epoch 16091.92327283 TLE of 16012A to the epoch of the epoch 16092.25625104 TLE of 16012L, yields a
> nearly exact match. Inclination and RAAN are within 0.0001 deg, argument of perigee within 0.08 deg, and argument of
> latitude within 0.003 deg. Perigee is within 0.012 km, apogee within 0.009 km. A conjunction analysis for 2016 Apr 01
> from 00-12 h UTC, reveals the orbits never more than 0.49 km apart. It is easy to conclude that they are of the same
> object.
>
> The same exercise with respect to the epoch 16092.18948948 TLE of 16012H yields not as close a match of the elements,
> including a 0.885 deg discrepancy in argument of latitude. The conjunction analysis reveals the orbits never closer than
> 100 km, and gradually separating.
>
> Ted Molczan


Hi Ted,

I now agree with you.

I actually initially did a similar exercise, but using the A elements from epoch 
16086. With hindsight, those are of course still from a short arc and (looking 
at the TLE to TLE variation) less accurate.

- Marco


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Received on Sat Apr 02 2016 - 12:53:09 UTC

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