Luminar Technologies Inc. shares surged another 8% on Tuesday after former NASA scientist Mark Rober test-drove a car equipped with the company’s lidar technology in a YouTube video and said it outperformed Tesla Inc.’s Autopilot feature.

Luminar shares have gained 44% in the latest three trading days.

In the video, which has drawn more than 11 million views since it was published to YouTube on March 15, Rober runs six tests assessing the lidar technology against Tesla’s system, which he said navigates using only “simple cameras” and image processing.

A representative for Luminar declined to comment, while a representative for Tesla didn’t respond to Bloomberg News’ request for comment.

Rober, who’s worked at NASA as well as Apple Inc., now runs a YouTube channel with more than 65 million subscribers.

His description for the YouTube video said that while Luminar provided the vehicle for testing purposes, he was not financially compensated by the company and the video wasn’t a paid promotion. Luminar’s X and LinkedIn accounts both posted links to Rober’s YouTube video on March 15.

Lidar, short for light detection and ranging, is a sensor technology that sends out laser pulses, then measures the time it takes for them to bounce off an object and return. That data is used to calculate how far away things are and create a three-dimensional map of the objects in an area.

The company will report fourth-quarter results after the market closes on March 20.