The Slow Fireball of December 22, 2015: A Russian Rocket Stage Comes Home Over Arizona

At about 6:10 p.m. PST on Tuesday, December 22, 2015 (7:10 p.m. in Arizona), people from Northern California to Las Vegas to Kingman watched a bright light move slowly across the sky and break into pieces. Some filmed it. Many guessed it was a meteor. A few joked about Santa’s sleigh. Others wondered about a missile.

By the next morning, three independent sources agreed on the answer. The object had launched from Kazakhstan the day before.

Three kinds of evidence, one answer

• Witnesses, via the American Meteor Society. AMS received more than 55 reports of a bright object over California, Nevada and Arizona “around 18:10 PST.” Its write-up that week was blunt: “It wasn’t a fireball.” It was Russian space debris, “a SL-4 rocket body that reentered the atmosphere somewhere above Arizona.” AMS also published an approximate trajectory based on the reports (Event #4087-2015).
• The military, via AP. U.S. Strategic Command spokeswoman Julie Ziegenhorn told the Associated Press that the fireball was “an SL-4 rocket body booster from Russia that was launched Monday.” SL-4 is the U.S. designation for the Soyuz rocket family. Space-debris expert David Wright of the Union of Concerned Scientists told AP that it was “not something people need to worry about.”
• The public catalog. Jonathan McDowell’s GCAT pins it down. On Monday, December 21, 2015, at 08:44 UTC, a Soyuz-2-1a lifted off from Baikonur carrying Progress MS-01, a cargo ship bound for the International Space Station. The rocket’s third stage, the Blok-I (catalog piece 2015-080B), reached a low orbit with the spacecraft and was left behind when they separated at 08:53 UTC. GCAT gives its decay time as 02:08 UTC on December 23. That’s 7:08 p.m. MST on December 22, within two minutes of the AMS time. GCAT lists the approximate re-entry point as about 35°N, 111°W, which is northern Arizona.

Why debris doesn’t look like a meteor

A meteor hits the atmosphere at tens of kilometers per second and is usually gone in a second or two. A spent rocket stage falling out of a low orbit is moving at under 8 km/s, so it crosses the sky far more slowly and can stay visible for many seconds. Because it’s a large, hollow, multi-part object, it tends to break into a train of glowing fragments as it burns up. Witnesses often compare that to a line of burning planes, or a “fireball” that won’t end. A slow, fragmenting, long-lasting light is the classic sign of re-entry.

Ledger status

Cited (explained). Independent sources agree on the time, path and identification: AMS’s witness data, the U.S. military’s identification and the public orbital catalog.

This is the re-entry half of the Sky Desk’s “was it a rocket?” check. The other half is the launch plume. Exactly two years later, on 22 December 2017, the Iridium-4 launch lit up the same Southwest sky. For telling a re-entry from a meteor, see the October meteor guide.

No map pin, and no debris hunting. AMS says only that the stage re-entered “somewhere above Arizona.” Nothing in these sources says that any piece reached the ground.

Sources

• Jonathan McDowell, General Catalog of Artificial Space Objects (GCAT), satellite catalog entry S41178 (2015-080B, Soyuz-2-1a No. 026 Blok-I; separated 2015 Dec 21 0853 UTC; decayed 2015 Dec 23 0208 UTC). Launch list entry 2015-080 (Soyuz-2-1a, Progress MS-01, 2015 Dec 21 0844:39 UTC). planet4589.org
• Vincent Perlerin, “Space Junk Re-entry over California and Nevada,” American Meteor Society, 23 Dec 2015 (AMS Event #4087-2015). Wayback copy. The live AMS site was partly offline when the ledger checked (Oct 2026).
• The Associated Press, “Fireball over western U.S. identified as Russian rocket debris,” via CBC News, 23 Dec 2015. cbc.ca