SpaceX plans to add more satellites to their Starlink constellation in the wee hours Wednesday morning with the Starlink 8-9 mission set to depart Space Launch Complex 40. Liftoff is currently targeted for 02:57 AM EDT with a launch window extending to 06:01:00 AM EDT the same day. If weather or technical reasons cause a scrub, an additional opportunities are also available on Sunday, July 7 starting at 12:28 AM EDT.

The booster used for the mission is Booster B1073, the same one that experienced an abort-at-ignition on its last launch attempt. After completing its boost cycle, B1073 on the company’s automated landing barge ‘A Shortfall Of Gravitas’ which is stationed at sea in the Atlantic Ocean offshore of the Carolinas. Since the booster will not be returning to the launch site, there will be no sonic booms on the Space Coast.

Payload

According to SpaceX, tonight’s payload is “20 Starlink satellites, including 13 with Direct to Cell capabilities, to low-Earth orbit from Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station in Florida.”

Weather

The 45th Weather Squadron forecasts an 80% chance of acceptable launch conditions. They do mention cumulus clouds as possibly playing the role of spoiler, however, with a long launch window, SpaceX can delay if fueling has not started and wait for improved conditions.

Trajectory

The planned trajectory for the launch is northeastwards, or right-to-left if you are a spectator in Florida looking towards the Atlantic Ocean.

Booster

SpaceX says that the booster, which is planned for use tonight, “[Will be] the 16th flight for the first-stage booster supporting this mission, which previously launched SES-22, ispace’s HAKUTO-R MISSION 1, Amazonas-6, CRS-27, Bandwagon-1, and 10 Starlink missions.”

That’s Booster B1073, the same one that experienced an abort-at-ignition on its last launch attempt. It has been re-inspected and any repairs needed have been completed, so it’s back to work for the well-experienced first stage.

Booster B1073		May 12, 2024
Flight	Mission	Date
1	Starlink 4-15	May 14, 2022
2	SES-22	June 29, 2022
3	Starlink 4-26	August 10, 2022
4	Starlink 4-35	September 24, 2022
5	HAKUTO-R	December 11, 2022
6	Amazonus Nexus	February 7, 2023
7	CRS-27	March 15, 2023
8	Starlink 6-2	April 19, 2023
9	Starlink 5-11	June 12, 2023
10	Starlink 6-12	September 4, 2023
11	Starlink 6-27	November 8, 2023
12	Starlink 6-37	January 15, 2024
13	Starlink 6-41	March 4, 2024
14	Bandwagon-1	April 7, 2024
15	Starlink 6-58	May 12, 2024

Countdown Timeline

There are key events in the countdown that you may hear called out in launch coverage.

Remember that once Propellant Loading (T-minus thirty-eight minutes) starts, Falcon 9 is committed to the launch attempt. Because of the nature of the cryogenic fuels used to power the rockets, any hold precludes a later launch attempt the same day. While it only rarely happens, there have been occasions where that has happened, and a launch scrub is called for the day’s attempt.

SpaceX provides the following countdown milestones on their mission information page:

Hours:Minutes:Seconds	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	1st stage LOX (liquid oxygen) loading begins
00:16:00	2nd 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

Typical SpaceX countdown timeline is presented for information purposes only.

Timeline of Falcon 9 Flight

SpaceX has published a timeline of expected events during the mission:

Hours:Minutes:Seconds	Event
00:00:00	Liftoff
00:01:10	Max-Q (Moment of peak mechanical stress on the rocket)
00:02:24	1st stage main engine cutoff (MECO)
00:02:28	1st and 2nd stages separate
00:02:35	2nd stage engine starts (SES-1)
00:02:54	Fairing deployment
00:06:09	1st stage entry burn begins
00:06:33	1st stage entry burn ends
00:07:53	1st stage landing burn begins
00:08:18	1st stage landing
00:08:38	2nd stage engine cutoff (SECO-1)
00:43:50	2nd stage engine starts (SES-2)
00:43:52	2nd stage engine cutoff (SECO-2)
00:52:44	Starlink satellites deploy

All events up to the end of the 1st stage entry burn should be visible for launch spectators watching the launch in person, so long as clouds are not blocking the viewer’s line of sight.

Watching Online

SpaceX will have a livestream of the launch on their website: Starlink 8-9. This will also be available on the X platform. Coverage starts about five minutes before liftoff.

Spaceflight Now will have coverage of the launch starting about one hour before liftoff on Youtube: link

For official updates regarding launch times, SpaceX.com is the best source of information. Starlink launch times change from time to time, and the company generally updates their website within minutes of the decision to change the launch time. This is very handy if none of the streaming options on YouTube have started their broadcasts.

Remember that there is a delay between a launch stream and the actual countdown clock. That is simply because of physics: it takes time for the signal to travel from the launch site, through the Internet, and back down to your phone, resulting in a five to fifteen-second delay.

Next Space Launch an app for iOS and Android phones, has a real-time countdown clock that is accurate to a second, give or take. The app is free. Search the App Store or Google Play.