# Celestrak GLONASS TLE's showing satellite numbers not listed in the GLONASS constellation, others missing

For a project, I'm retrieving TLE information live from http://celestrak.com/ and using them to simulate satellite orbits. The TLE's for the GLONASS constellation (http://celestrak.com/NORAD/elements/glo-ops.txt) seem to be showing signals from some satellites that aren't listed in the GLONASS constellation (https://www.glonass-iac.ru/en/CUSGLONASS/index.php) where other numbers that are listed as existing in the constellation are missing.

Specifically:

COSMOS 2471 (701K), COSMOS 2425 (716), and COSMOS 2458 (734) are shown in Celestrak but not in the constellation status list.

COSMOS 2527 (756) and COSMOS 2529 (757) are listed in the constellation status but are not in the list of TLE's from Celestrak.

Does anybody know what's going on here? If the error lies on Celestrak's side, is there a better service available to get real-time TLE data for GNSS?

## 1 Answer

tl;dr: Celestrak offers those short lists for convenience only. If you want to know the TLE of a group of satellites, look them up explicitly using their IDs. It looks like once a GLONASS satellite gets on the list by being commissioned for GNSS, it stays on the list even if GLONASS stops using it. The two satellites that are not yet on the Celestrak convenience list have been launched within the last seven months. That could be an oversight or perhaps these convenience lists are not updated very frequently. Celestrak does provide TLEs for them if you look them up explicitly.

COSMOS 2471 (701K), COSMOS 2425 (716), and COSMOS 2458 (734) are shown in Celestrak but not in the constellation status list.

Here are their current Satcat entries. Scrolls right:

COSMOS 2471   2011-009A    37372 M*P COSMOS 2471 [GLONASS-K]   CIS    2011-02-26  PLMSC                675.7   65.7   19155   19104    7.9433
COSMOS 2425   2006-062A    29670 M*+ COSMOS 2425 [GLONASS-M]   CIS    2006-12-25  TYMSC                675.7   65.2   19188   19071    5.0119
COSMOS 2458   2009-070C    36113 M*+ COSMOS 2458 [GLONASS-M]   CIS    2009-12-14  TYMSC                675.8   64.2   19138   19123    5.0945


These objects are physically present in Earth orbit and therefore appear in the catalog, even if they are not being actively used for GNSS or included on other lists. Launch dates from 2006 to 2011.

• 2011-009A has a status P rather than + suggests the status is not that of an active satellite. Celestrak's SATCAT Format Documentation explains further.

COSMOS 2527 (756) and COSMOS 2529 (757) are listed in the constellation status but are not in the list of TLE's from Celestrak.

Here are their current Satcat entries. Scrolls right:

COSMOS 2527   2018-053A    43508  *+ COSMOS 2527 [GLONASS-M]   CIS    2018-06-16  PLMSC                675.7   64.8   19145   19115     N/A
COSMOS 2529   2018-086A    43687  *+ COSMOS 2529 [GLONASS-M]   CIS    2018-11-03  PLMSC                675.7   64.8   19155   19105     N/A


Celestrak certainly has TLE's for these objects, they are just not listed on that "convenience list".

Here are a list of alternate names (just fyi): https://www.celestrak.com/pub/satcat-annex.txt