SpaceX plans to launch a rocket tonight that has a low probability of returning to Earth intact.
A launch window for the SES-9 mission, which will deliver a commercial communications satellite into orbit, opens at 6:46 p.m. But the satellite is destined for a "geostationary transfer orbit," which is more difficult to return from, SpaceX says. In addition, the landing site is SpaceX's drone ship, instead of dry land. The last three attempts to land a rocket on the drone ship ended in failure.
The Boeing-built SES-9 will eventually join the SES-7 satellite above the Asia-Pacific region, providing high-speed broadband services to remote regions, SpaceX says. But the journey to get there is more arduous than other missions, The Verge reports.
In order to arrive in geostationary transit orbit at its intended location, the satellite will separate from the rocket once it reaches space and complete the last step of the journey on its own. That could take several months, so SpaceX has agreed to drop off SES-9 at a higher altitude to reduce the distance it has to travel by itself.
The additional height means the rocket will be traveling faster as it re-enters Earth's atmosphere, making a successful landing unlikely.
"Given this mission's unique GTO profile, a successful landing is not expected," the company said in a statement.
SpaceX has already mastered a ground landing of the Falcon 9 rocket, which was the first recovery of an orbital-class booster, according to CEO Elon Musk. Traditionally, these rockets have been destroyed after lift-off, so SpaceX and other space firms have been working on reusable rockets. It's a tricky manuever, but one that could save lots of money if executed correctly.
You can view a livestream of the launch at SpaceX's website starting approximately 20 minutes before the expected lift-off time of 6:46 p.m.
This article originally appeared on PCMag.com.