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Emily LakdawallaOctober 26, 2011

NPP Tweetup schedule and launch timeline

This evening I'll be headed up to Lompoc, California, to participate in my first Tweetup along with 25 other Tweeters. The Tweetup will be all day tomorrow and includes briefings by NPP managers, scientists, and engineers, followed by a tour of the Mission Director's Center with George Diller. Diller's voice will be familiar to many of you; he's the one who always announces and commentates NASA's launches. After lunch we'll get a tour of Vandenberg Air Force Base, including the Western Range Operations Control Center, the Boathouse (where Delta rockets are delivered), and Space Launch Complex-6, launch site for Delta IV rockets. The day's highlight will occur at the end, when we'll be treated to a photo opportunity at Space Launch Complex-2, near the Delta II rocket that'll be launching very early the next morning with the NPP spacecraft aboard. I'll be tweeting occasionally but expect to be letting other participants do a lot of the commentary; you can follow the whole thing using the #NASATweetup hashtag.

I imagine there'll be some socializing and very little sleep before the planned launch at 2:48 Friday morning. The Tweetup participants will be viewing the launch from the same spot as the rest of the public. One hour after launch, NPP should be separated from the second stage, in its orbit, communicating with Earth!

Here's a timeline of the launch milestones:

Time (s)Time (PDT)Time (UTC)Event
0.0 02:48:01 09:48:01 Liftoff!
86.0 02:49:27 09:49:27 Six ground-lit solid rocket boosters jettison
The six boosters that ignited on the ground will be dropped and three more boosters ignited.
131.5 02:50:12 09:50:13 Three air-lit solid rocket boosters jettison
263.4 02:52:24 09:52:24 Main engine cutoff (MECO)
276.9 02:52:38 09:52:38 Second-stage ignition
281.0 02:52:42 09:52:42 Payload fairing jettison
623.7 02:58:25 09:58:25 First cutoff of second stage rocket (SECO-1)
At this point, NPP and its second stage will be at the perigee of an elliptical orbit varying from 195 to 853 kilometers altitude.
3125.0 03:40:06 10:40:06 First restart of second stage rocket
The second stage fires near apogee to circularize the orbit to one with an altitude of about 820 kilometers.
3146.7 03:40:28 10:40:28 Second cutoff of second stage rocket (SECO-2)
3525.0 03:46:46 10:46:46 NPP separation
3600.0 03:48:01 10:48:01 Satellite signal acquisition
3930.0 03:53:31 10:53:31 Cold gas evasive maneuver
The second stage performs a small maneuver to move it away from NPP's orbit.
5400.0 04:18:01 11:18:01 NPP solar array deployment
5550.0 04:20:31 11:20:31 Second restart of second stage rocket
The second stage will drop the orbit perigee back down to 340 kilometers altitude.
5589.2 04:21:10 11:21:10 Third cutoff of second stage rocket (SECO-3)
5900.0 04:26:21 11:26:21 Deploy P-POD-1
6000.0 04:28:01 11:28:01 Deploy P-POD-2
6100.0 04:29:41 11:29:41 Deploy P-POD-3
6898.6 04:43:00 11:43:00 Third restart of second stage rocket
6390.5 04:34:32 11:34:31 Final cutoff of second stage rocket (SECO-4)
The final burn drops the orbit to one that will decay rapidly, disposing the second stage by burning it up in the atmosphere.

Read more: Earth observing missions

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Emily Lakdawalla

Solar System Specialist for The Planetary Society
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