Relativity Space called off the first launch attempt of the Terran 1 rocket a little over a half hour before the close of the launch window, joining every other space company in history in not launching their vehicle on the first attempt.

The company has a backup launch window tomorrow, though it’s unclear if they’ll attempt the launch again. Relativity ended their livestream without disclosing further details as to the cause of the scrub. TechCrunch will update the story when more details become available.

Relativity Space is the brain child of Tim Ellis and Jordan Noone, who suspected that they could dramatically decrease launch costs by using innovative 3D-printing techniques and using those techniques to manufacture as many rocket parts as possible.

The result is Terran 1, which is 85% 3D-printed by mass, and the goal is to increase that even further — to manufacture a rocket that’s composed of upwards of 95% 3D-printed material. To get there, the company’s raised a lot of money: more than $1 billion, propelling their valuation to $4.2 billion as of June 2021. Relativity’s workforce now numbers in the thousands, and the company has over 1 million square feet of manufacturing space under its purview.

Today’s call to scrub came after an abort at T-70 seconds, due to oxygen temperatures in the rocket’s second stage being outside of normal limits, but they were able to resolve the issue and continue countdown until the call to scrub.

There is no fairing or payload on this first launch, which the company is using essentially as a technological validator as it continues development on the heavier-lift Terran R rocket. A successful launch would go far in proving out the company’s 3D-printed rocket architecture and act as a proof-of-concept more generally. Follow along with the company on Twitter for more updates on the launch.