SpaceX's CRS-9 Mission Launches Tonight

It's launch day for a Dragon commercial resupply capsule to the International Space Station. More precisely, it is launch day in the U.S. in every time zone EXCEPT the one (Eastern Daylight Time) where the launch actually happens: Cape Canaveral on Florida's Space Coast.

Launch times that switch days depending on which U.S. time zone you are in can be confusing, so if you plan to watch live, here are the launch times by time zone and day for the continental U.S., as well as Central Europe and UTC:

12:45 a.m. Monday, July 18 EDT
11:45 p.m. Sunday, July 17 CDT
10:45 p.m. Sunday, July 17 MDT
9:45 p.m. Sunday, July 17 PDT

06:45, Monday, July 18 CEST
4:45 a.m., Monday, July 18 UTC 

This launch window is instantaneous. 

If the launch does not occur tonight at 12:45 a.m. EDT, July 18, there is another instantaneous backup window at 12:00 a.m. (midnight) EDT on July 20. That is mid-to-late evening this Tuesday, July 19, for most viewers in the continental U.S. in time zones other than Eastern (e.g., 9 p.m. PDT, July 19). This means 06:00 CEST on July 19 in Central Europe and 4:00 a.m., July 19 UTC.

SpaceX will host a live webcast at http://www.spacex.com/webcast.

The company will almost certainly also stream a technical webcast for those who are more interested in engineering details and telemetry than the webcast from SpaceX HQ. The link to the technical broadcast usually appears once the webcast goes live at the above link.

As with every SpaceX mission since last December, the private rocket company will attempt a landing tonight to recover the spent first stage of the Falcon 9 rocket. 

Earlier this year, SpaceX successfully landed spent rockets used in missions on land near Cape Canaveral (one time) and on an autonomous ocean-going barge three consecutive times, most recently on May 27, 2016, when the Thaicom-8 mission delivered a payload into geostationary transfer orbit. However, last month's barge landing attempt as part of the successful Eutelsat/ABS mission ended in a RUD - a rapid unscheduled disassembly at sea, in the words of Elon Musk. The spent rocket stage reached the barge, but disintegrated on touchdown.

SpaceX will attempt another land-based landing near Cape Canaveral tonight. The third of three burns, the landing burn, is scheduled to begin at 7 minutes, 38 seconds after liftoff. It is this landing burn that occurs closest to the ground, just before the rocket attempts to land.

The two prior burns, the boost back burn starts at 2 minutes, 42 seconds after liftoff, followed by the entry burn at 6 minutes and 31 seconds after liftoff.

Image credit: Space X

Graphic illustrating the stages of launch, landing and mission completion. Graphic is for barge landing, but stages are the same for a ground-based landing
(click to enlarge)

When the webcast begins, pay attention to the legend below the video that shows when to expect the different launch and landing milestones. Some of them are included in the graphic above. SpaceX has been very good about providing live footage not just of its mission launches, but its landing attempts as well. Night landings, though, pose visibility challenges. In case of a successful landing - or even an unsuccessful one - expect a brief camera whiteout as the brightness of the landing burn overloads the cameras for a few seconds before we will know if the rocket has landed upright.

Image Credit: SpaceX

Official Mission Patch for SpaceX's 9th Commercial Resupply (CRS) Mission to the International Space Station under contract with NASA

Image credit: SpaceX 

Dragon capsule atop SpaceX's flagship Falcon 9 rocket on the pad at Cape Canaveral awaiting launch to the ISS on July 18