URGENT: We will run out of 5-digit catalog numbers at 69999 not 99999, which is estimated to occur around 2026‑07‑20 (we're currently at 68764). At that point, newly cataloged objects will have 6-digit catalog numbers of 100000+ and GP data will not be available for them using the TLE format. CelesTrak developed new formats that removed this limitation (and finally fixed the Y2K problem) in May 2020 and immediately began providing GP data in those formats for software developers. The same limitations apply to the legacy fixed-field SATCAT. Follow @TSKelso on Bluesky for the latest updates, tutorials, and changes as we approach this transition. Spread the word! ‑ TS

SOCRATES Plus

Search Results

CelesTrak

Search parameters:

  • NORAD Catalog Number(s): 25544
  • Order by Minimum Range
  • Return first 25 items


Data current as of 2026 Apr 19 02:20:54 UTC

Computation Interval: Start = 2026 Apr 19 02:00:00 UTC, Stop = 2026 Apr 26 02:00:00 UTC
Computation Threshold: 5.0 km
Considering: 15,143 Primaries, 30,778 Secondaries (136,097 Conjunctions)
9 SGP4 Propagation Errors
Computation run time: 10h 46m 07.812s

SOCRATES Format Documentation

See notes at bottom of page for data field descriptions

Data
&
Graphs
NORAD
Catalog
Number
Name [Ops Status] Days
Since
Epoch
TCA
(UTC)
Min
Range
(km)
Relative
Speed
(km/sec)
Max
Probability
Dilution
Threshold
(km)
GP Data 25544 ISS (ZARYA) [+] 3.816 2026-04-22 14:18:27.562 2.078 7.805
50 km All 59148 HAMMER [+] 3.757 5.440E-05 0.558
GP Data 25544 ISS (ZARYA) [+] 4.125 2026-04-22 21:44:02.122 3.291 6.263
50 km All 60558 FLOCK 4BE-35 [P] 4.056 2.282E-05 0.840
GP Data 25544 ISS (ZARYA) [+] 4.158 2026-04-22 22:30:57.416 3.399 6.207
50 km All 60556 KANYINI [+] 4.423 2.142E-05 0.867
GP Data 25544 ISS (ZARYA) [+] 4.957 2026-04-23 17:42:05.272 3.747 13.993
50 km All 61761 OBJECT AC [+] 4.937 9.670E-06 1.742
GP Data 25544 ISS (ZARYA) [+] 6.861 2026-04-25 15:24:03.108 4.199 6.831
50 km All 56426 STARLINK-5352 [+] 6.808 3.429E-05 1.091

5 records found

Data Fields:
  • Data: The GP Data button links to a page which provides the GP data used to generate the associated prediction.
  • NORAD Catalog Number: NORAD Catalog Numbers of the two conjuncting objects.
  • Name: SATCAT names of the two conjuncting objects. Operational status of each object is shown in brackets, using the standard CelesTrak SATCAT codes.
  • Days Since Epoch: The number of days from the epoch of the NORAD GP or SupGP (green) element set used to produce the prediction until the time of closest approach for the conjunction.
  • TCA (UTC): Time of closest approach.
  • Min Range (km): The distance between the two conjuncting objects at the time of closest approach.
  • Relative Speed (km/sec): Relative speed of the two conjuncting objects at the time of closest approach.
  • Max Probability: Given fixed spherical object radii and relative distance at the time of closest approach (TCA), the projected covariance ellipse is sized and oriented to produce the maximum probability. For these reports the ratio of major-to-minor axes of the projected covariance ellipse is set using radial, in-track, and cross-track values of 100 m, 300 m, 100 m, respectively. If the combined object radius is greater than the relative distance, the maximum probability will be one; such occurrences are not addressed here. For more details on the maximum probability method, see Dr. Sal Alfano's paper titled "Relating Position Uncertainty to Maximum Conjunction Probability".
  • Dilution Threshold (km): The standard deviation that produces the maximum probability defines the threshold of dilution. A smaller or larger standard deviation will produce a smaller probability. In the case of computing true probability with a smaller standard deviation, the data is of sufficient quality to associate low probability with low risk. For a larger standard deviation, this is not the case and the resulting true probability calculation becomes "diluted." If operating in this dilution region, the recommendation is to obtain better data and reassess the encounter. If time or resources do not permit, then the maximum probability should be used in place of the true probability.
  • SGP4 Propagation Errors: A list of objects which were not screened because their GP data shows they have already decayed (but haven't yet been reflected in the SATCAT) or will decay prior to the end of the computation interval.