Photo: Charles Boyer, Talk of Titusville
SpaceX and the US Space Force have set a liftoff time for the planned Falcon Heavy Launch from Kennedy Space Center tomorrow, December 28, 2023: 8:07pm Eastern Standard Time.
Note: this article was updated at 4:45pm to reflect new weather forecasts.
Payload
Falcon Heavy will launch USSF-52, consisting of the X-37B Orbital Test Vehicle for the United States Space Force, and various other tests, including NASA’s Seeds-2 experiment. That will investigate the effects of radiation on plant seeds during spaceflight. X-37B is a Boeing-built winged spacecraft embarking on its seventh mission in orbit, or OTV-7 in USSF parlance. Its stated mission is to test its capacities to change its orbital regime and materials test for the Space Force.
According to SpaceX, “this will be the fifth launch and landing of these Falcon Heavy side boosters, which previously supported USSF-44, USSF-67, Hughes JUPTER 3, and NASA’s Psyche mission. Following booster separation, Falcon Heavy’s two side boosters will land on SpaceX’s Landing Zones 1 and 2 (LZ-1 and LZ-2) at Cape Canaveral Space Force Station in Florida.” The surrounding area will hear sonic booms marking the return of the boosters shortly afterward.
Weather Update, 4:15pm, December 27, 2023:
The 45th Weather Wing has released their forecast and they predict a high probability that conditions to be much better than was thought even as early as this morning:
It’s worth noting that the 45th Weather Wing is forecasting the chances of acceptable launch conditions, while the general weather forecasts issued by the National Weather Service and by commercial entities like Weather Channel or local stations do not take specific launch criteria into consideration in their weather products. Some local television stations do include a mention their take on launch forecasts, but they are neither definitive nor offical. 45th Weather Wing is responsible to the range and its clients and ultimately, it will be them that makes the call.
We will update this article with new forecasts as they become available. Check back, conditions are changing and the forecast may change with it — up to and including the last minute of the countdown.
What Are The Weather Related Launch Criteria, Anyway?
As a starter, it is very helpful to understand what the 45th Weather Wing is predicting in their forecasts: the Probability Of Violation (POV) of Lightning Launch Commit Criteria (LLCC) and “user constraints” — meaning the limitations of the rocket that’s being launched coupled with its payload. Different rockets have different weather limitations such as surface winds, precipitation and even temperature, and the 45th calls that “user constraints.”
LLCC — lightning — obviously comes into play on the coastline of central Florida most months of the year. Storms can and do pop up all over the region on a daily basis, and in fact, this region of the country is among the top three in terms of lightning strikes and intensity. Thunderstorms also have massively tall clouds, and they are packed with an incredible amount of potential energy. A rocket flying also builds up a charge due to friction in the atmosphere, and when those two conditions are put together, the chances of a catastrophic lighting strike can get very high.
The 45th Weather Wing assembles all of that data and then calculates the Probability of Violation. For tomorrow, they expect a 20% — one in five — probability of a Violation. Taken the other way, they are also saying the chances for acceptable conditions are 80%.
More Information: Space Launch Delta 45 Launch Forecast FAQs
Previous Delays
Weather and technical issues have caused multiple delays since the original planned launch date, December 8, 2023. A weather scrub stood down the launch on that day, then SpaceX delayed with less than an hour left on the countdown clock, citing “ground side issues” on their next attempt. It then planned for a Wednesday, December 13th launch date but then decided Tuesday, December 12th that it needed more time to ensure the spacecraft is flight-ready. December 28th is the next launch date SpaceX has named since then.
Launch viewers who have not purchased tickets for seeing the launch at the Kennedy Space Center Visitors Center may view the liftoff and returning boosters along the Indian River in Titusville. Given that this is the holiday season and in-season for tourists in the area, arriving early is advised. Be prepared for some traffic after the launch as well.