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PUNCH (Polarimeter to Unify the Corona and Heliosphere)

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Key Milestones for Today’s Launch

The fairing of a rocket is visible against the launch tower. The outside of the fairing has logos for NASA, SPHEREx, and PUNCH.
A SpaceX Falcon 9 rocket, carrying NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) observatory and PUNCH (Polarimeter to Unify the Corona and Heliosphere) satellites, is vertical at Space Launch Complex 4 East from Vandenberg Space Force Base in California on Saturday, March 8, 2025. Photo credit: SpaceX

We’re a little under an hour and a half away from today’s launch of NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) and PUNCH (Polarimeter to Unify the Corona and Heliosphere) missions aboard a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California. Liftoff is targeted for 11:10 p.m. EDT (8:10 p.m. PDT).

Here’s a closer look at some of today’s important countdown and ascent milestones (all times are approximate):

COUNTDOWN:
Hr/Min/Sec    Event
– 00:38:00 SpaceX launch director verifies go for propellant load
– 00:35:00 RP-1 (rocket grade kerosene) loading begins
– 00:35:00 First stage liquid oxygen (LOX) loading begins
– 00:16:00 Second stage LOX loading begins
– 00:07:00 Falcon 9 begins engine chill prior to launch
– 00:01:00 Command flight computer to begin final prelaunch checks
– 00:01:00 Propellant tank pressurization to flight pressure begins
– 00:00:45 SpaceX launch director verifies go for launch
– 00:00:03 Engine controller commands engine ignition sequence to start
00:00:00 Falcon 9 liftoff

LAUNCH, LANDING, AND SPACECRAFT DEPLOYMENT:
Hr/Min/Sec Event
00:01:07 Max Q (moment of peak mechanical stress on the rocket)
00:02:17 First stage main engine cutoff (MECO)
00:02:21 First and second stages separate
00:02:28 Second stage engine starts (SES-1)
00:03:05 Fairing jettison
00:07:39 First stage landing
00:08:15 Second stage engine cutoff (SECO-1)
00:39:29 Second stage engine starts (SES-2)
00:40:12 Second stage engine cutoff (SECO-2)
00:41:44 SPHEREx separation
00:52:04 PUNCH separation
00:52:54 PUNCH separation
01:29:55 Second stage engine starts (SES-3)
01:29:57 Second stage engine cutoff (SECO-3)
02:02:21 Second stage controlled entry into Pacific Ocean

The live launch broadcast will begin at 10:15 p.m. EDT (7:15 p.m. PDT) and will air live on NASA+ and the agency’s website.

Learn how to stream NASA content through a variety of platforms, including social media. You can also continue following along right here on the blog as we take you through the entire flight profile.