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Key Milestones for Today’s Launch – PUNCH [1]

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Date: 2025-03-10  

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

  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.

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[1] Url: https://blogs.nasa.gov/punch/2025/03/10/key-milestones-for-todays-launch/

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