If tonight’s launch is scrubbed, SpaceX will try again the same time tomorrow.
Another launch means another potential landing of the Falcon 9’s first stage. But, SpaceX isn’t expecting a successful landing. Here’s what they say in the press kit covering today’s launch.
“This mission is going to a Geostationary Transfer Orbit. Following stage separation, the first stage of the Falcon 9 will attempt an experimental landing on the “Of Course I Still Love You” droneship. Given this mission’s unique GTO profile, a successful landing is not expected.”
Why can’t SpaceX just come back to near the launch site like they did in December? Musk says it’s “all about speed.”
As mentioned before, ship landings are needed for high velocity missions. Altitude & distance don’t mean much for orbit. All about speed.
Speed is the most important thing to remember when thinking about first stage rocket landings. According to SpaceX, there are certain thresholds that determine where they can land the first stage rocket. “In the case of the Falcon 9 rocket, the boost stage is able to accelerate a payload mass of 125 metric tons to 8000 km/h and land on an ocean platform or to 5000 km/h and land back at the launch site. The second one is lower because the rocket is moving super fast away from the launch site, so it has to do a screeching U-turn with nitrogen attitude thrusters, then fire the engines to create a reversed ballistic arc, then reorient again for atmospheric entry and have the engines pointed in the right direction for the landing burn.”
A beautiful long-exposure photograph perfectly illustrates how the launch site landing worked.
Today’s launch is pushing a commercial communications satellite into a Geostationary Transfer Orbit (GTO). This is a much higher orbit than the satellites launched in December. And that means more speed to fling the satellite into the desired orbit.
SpaceX is downplaying the possibilities of a successful landing on the drone ship, but I wouldn’t be shocked if they end up nailing it. They’ve come incredibly close in the past few launches. The orbital altitude for this mission is what makes it tricky. Even if SpaceX fails, today’s mission will give them valuable insight into making future missions succeed.
SpaceX’s payload is SES-9
SES-9 is a commercial communications satellite from SES, a global communications company. The new satellite will increase internet, TV and mobile coverage to more than 20 countries in Southeast Asia. SES-9 will be the 7th SES satellite expanding coverage for this area of the world.
Once the satellite is in orbit, it’s expected to operate there for 15 years.
Here’s a timeline for today’s launch.
SpaceX is hosting a live webcast of the launch tonight. Coverage starts 20 minutes before liftoff.