SpaceX may be yet to launch any living human astronauts into space, but the remains of over 150 people are going to get the ride of their afterlives on Monday night thanks to the company’s Falcon Heavy rocket. Among the various satellites and instruments being carried into orbit by SpaceX this evening is a collection of “spaceflight memorials” by a company called Celestis.

Celestis offers a rather unique service in that it provides a way for family members to send the remains of their loved ones into space as a tribute and memorial. In this case, the company bought space aboard the Falcon Heavy and will be carrying out the wishes of many of its clients at once, sending the cremated remains of 152 people into Earth orbit.

During tonight’s launch — assuming it proceeds during its scheduled launch window — the human remains will be released into orbit aboard one of two dozen satellites the Falcon Heavy is hauling.

Among those included in tonight’s launch — Celestis calls them “participants” — are former NASA astronaut Bill Pogue, Japanese professional basketball star Masaru Tomita, and spaceflight historian Dr. James M. Busby. The full list of 152 individuals, and their memorials, is available online.

Believe it or not, this isn’t the first time that Celestis has sent human remains into space — in fact, it’s not even close. The company has successfully completed 15 launches already, sending the ashes of celebrities like Star Trek “Scotty” actor James Doohan and scientist Eugene Shoemaker into space in decades past.

Tonight’s Falcon Heavy launch is scheduled to take place at 11:30 p.m. EDT tonight (Monday, June 24th). Following the launch, Celestis will actually be hosting its own “Memorial Service” live stream to honor all of the individuals that were carried skyward. You can watch that live stream starting a couple of hours after the launch via the live stream window below.