How much debris is in orbit, and where did it come from?

Steps

1. No API. Downloaded the SATCAT CSV (70,955 objects) once, the GP element sets for NAME=DEB (10,225 rows) and NAME=R/B (2,118 rows) once each, and three NASA Orbital Debris Quarterly News PDFs. SATCAT gives debris the launch date of its parent, so a breakup is filed under the parent's launch year. The year a piece entered the catalog is estimated from its NORAD number: numbers are issued in order, so a piece is dated by interpolating between the launch dates of the two payloads or rocket bodies with the nearest numbers on either side. Leave-one-out test on 32,119 payloads and rocket bodies: median error 0.0 days, 99.6% within 30 days, 99.6% within a year. Against NASA's own box scores the estimated series gives 10,660 rocket bodies and debris on 2009-04-01 (NASA 10,671) and 16,938 on 2022-02-04 (NASA 17,011). For every owner in CelesTrak's Boxscore (136 rows) the non-payload objects on orbit, decayed and total equal this script's counts (0 differences).
2. Tracked objects are the rows of the CelesTrak SATCAT. An object is in orbit when it has no decay date. Type is SATCAT's OBJECT_TYPE: PAY (payload), R/B (rocket body), DEB (debris) or UNK (unknown). CelesTrak's Boxscore calls every non-payload object debris; this page keeps rocket bodies apart. Only objects large enough for the U.S. Space Surveillance Network to track (about 10 cm in low Earth orbit) are in the catalog. The year-end series counts objects with no decay date at the end of each year: payloads, rocket bodies and unknown objects by launch year, and debris by the year it is estimated to have entered the catalog (see query), minus decays by decay year. Altitude is the mean of apogee and perigee.
3. Event pieces: SATCAT rows of type DEB named FENGYUN 1C DEB, IRIDIUM 33 DEB, COSMOS 2251 DEB and COSMOS 1408 DEB. The parent objects (NORAD 25730, 24946, 22675 and 13552) are checked against the designators NASA prints.

70 yearly rows (1957 to 2026) from 42,986 non-payload and 27,969 payload catalog entries. Unit: Number of tracked objects; altitudes in kilometres. Every derived figure on this page (changes, indexes, averages, counts) is computed from the published rows, and the table under each chart says how.

Checks

• For all 136 owners in CelesTrak's own Boxscore page, the non-payload objects on orbit, decayed and total equal this page's counts: 0 differences (15,018 on orbit, 27,968 decayed).
• The year-end series ends at 35,273, the number of objects with no decay date, and the yearly debris additions add up to 35,911, every debris object in the catalog.
• The estimated catalog dates reproduce NASA's own box scores of the whole catalog: 10,660 rocket bodies and debris on Apr 1, 2009 against NASA's 10,671 (-0.1%), and 16,938 on Feb 4, 2022 against 17,011 (-0.4%). Payloads need no estimate and differ from NASA's spacecraft counts by 12.8% and 1.9%; the cause is not known.
• Leave-one-out test of the dating on 32,119 payloads and rocket bodies: median error 0 days, 99.6% within 30 days. For Cosmos 1408 the estimate gives 1,605 pieces by Mar 7, 2022; NASA reports 1,604. For the Iridium and Cosmos collision it gives 809 by the end of March 2009; NASA reports 823.
• The globe file (debris_snapshot.json) has 12,310 rows; 12,306 of 12,310 have apogee and perigee within 15 km of the catalog's own values when recomputed from their mean motion.

Caveats

• Only tracked objects are counted. Debris from 1 mm to 10 cm is far more numerous (NASA's models estimate it in the hundreds of thousands to millions) and is in no public catalog. Debris years before the last point are estimates (see the method); the last point and every count of objects now in orbit are exact. SATCAT status and orbit sizes can lag: an object whose elements are old keeps its last known orbit. Debris is counted by object, not by mass. The Fengyun-1C, Iridium 33, Cosmos 2251 and Cosmos 1408 piece counts come from SATCAT names; the catalog may place a few pieces of a breakup under other names.
• 2,653 of the 14,963 debris and rocket bodies in orbit have no current public orbit (most have elements older than about 30 days or none public), so they are counted here but not in the globe file.
• Years of new debris are estimates from NORAD numbers, which are issued in the order objects are catalogued. They are accurate to days for payloads, but a breakup's pieces can take months to be numbered, so a piece's year may differ from the year it was made.
• Pieces of a named event are those SATCAT names; a few pieces of the same breakup may carry other names. NASA's published counts are from weeks after each event and are lower than today's catalog.

Releases and revisions

• SATCAT file timestamp Thu, 08 Oct 2026 21:03:46 GMT; the element lists were current as of 2026 Oct 08 21:06:02 UTC. CelesTrak updates the catalog once or twice a day; this page does not refresh itself.
• The three NASA reports are fixed documents (April 2007, April 2009, March 2022). Next: re-run space_debris.py to refresh. It downloads each CelesTrak file once and stops on any reply other than HTTP 200, as CelesTrak's usage policy asks.