ULA Atlas V STP-3 Launch

After a series of delays due to weather and technical problems, a United Launch Alliance Atlas V was launched at 10:19 UTC on 2021-12-07, carrying a pair of U.S. Space Force technology demonstrator satellites to geostationary orbit. Among the experiments on board is a NASA satellite laser data link demonstrator. The launcher’s Centaur upper stage will deliver the payloads directly into geostationary orbit rather than the usual flight profile where they are injected into a geosynchronous transfer orbit and then circularise with their own propellant. The Centaur will perform three burns, and the total mission from launch to payload separation will be over seven hours, the longest in Atlas history. Here is the ULA data sheet on the mission.

I have cued the video to start one minute before launch; scroll back to see the preliminaries.


I remember the hopes placed in the original Atlas ICBM in the late '50’s, when many impressive explosions on or just above launch pads were common occurrences. For some reason I recall the small vernier plumes coming out the sides, just above the 2 lateral strap-on booster engines, I think. In those days, I was up on the thrust of each rocket. Now, there are way too many and I imagine today’s Atlas little resembles the original.

The only thing the present-day Atlas shares with the original is the name. It uses different (Russian) engines, a completely different structure (isogrid instead of pressure-stabilised) built from different material (aluminium instead of stainless steel), a different staging structure (stacked instead of 1-1/2 stage), roll control by full gimbaling two nozzles instead of vernier engines, and support for solid rocket strap-on boosters. It is also larger than the original Atlas, 3.7 metres diameter, up from 3.0.

Here is a Scott Manley video about the evolution of the Atlas family prepared for the 60th anniversary of the first Atlas launch in 1957.


Interesting to see what looks like a safety flare (Oh-oh! CO2) close to the launch pad in the Atlas V launch video. Is that required by the particular fuel used in this rocket?