SpaceX Dragon Uses LIDAR

Elon Musk tweeted that SpaceX developed and uses LIDAR for Dragon docking with the Space Station. Elon and Tesla do not use LIDAR for for self-driving.

Elon commented that if you are going to do active photon generation then use an occlusion penetrating wavelength like precision radar at ~4mm.

A search online does not find descriptions of commercial LIDAR working at 4 millimeters which is about 80 Gigahertz. There are radar at 80GHz and those seem to be used as alternative to ultrasonic systems for checking the level liquids in a container. There are some millimeter mapping systems for radar at those wavelengths to locate studs and pipes in walls. There needs to be a lot of calculation and analysis of the reflections.

LiDAR uses electromagnetic (EM) waves in the optical and infrared wavelengths. It is an active sensor, meaning that it sends out an EM wave and receives the reflected signal back. It is similar to microwave radar, except at a much shorter wavelength.

A key advantage of mmWave radar is its imperviousness to adverse environmental conditions, such as smoke, fog and dust.

LIDAR is an acronym for LIght Detection And Ranging. It is also called optical radar, laser radar or ladar under different application scenarios. Many remote sensing applications demand for the foliage obscured man-made objects detection. These applications may range from civilian applications, such as search and rescue missions in densely forested areas, to military applications, such as detecting camouflaged enemy vehicles. Traditional passive remote sensing has very limited capability in foliage obscured target detection.

There is new academic work creating a chip that generates radar at around 80 GHz.

Penetrating trees and branches it at a different wavelength.

SOURCES- Elon Musk, SpaceX, Arxiv
Written By Brian Wang,

12 thoughts on “SpaceX Dragon Uses LIDAR”

  1. There are very few radars at 80 GHz if you search by that term. But automotive radar produced by the 100's of millions operates in two bands 76-77 GHz and 77 – 81 GHz. Lidar for automotive marker is priced in low hundreds of dollars right now. The cost driver is mechanical spinning mirrors to scan the beam. Solid state beam movement is coming and will drive cost down further. Automotive radar is 20 dollars at the low end and 250 at the high end. Low end can compete with ultrasonic proximity sensors, high end will compete with lidar on imaging.

    Roads are designed to be viewed by human eyes, so cameras are compatible. Other sensors have to live with limitations. Lidar can't see black cars very well. Radar sees too many bright spots, as if the road covered with mirrors reflecting bright lights into it's "eyes". On the other hand some vehicles are "stealthy" and return very little signal.

    Eventually, roads and other vehicle may have requirements for optical, infrared, and microwave reflectivity. Boats and buoys already have radar reflectors added for increased visibility and safety. We have reflective stripes and markers for eyes, safety require similar measures for other sensors.

  2. Perhaps one day, future cities could have other signals built into every traffic sign, like transponders, RFID, QR code, etc. As technology costs improve, why do we only have to resign ourselves to only doing things the old way?

  3. Well, he's right. LIDAR certainly reduces computational load relative to image interpretation from a camera, but you have to do the image interpretation anyway to read the traffic signs and lines on the pavement. If you're going to use active sensors, use ones that are penetrating.

  4. People couldn't help but notice how the astronauts in Crew Dragon are just looking at the pretty screens while Dragon's automatic pilot does it all.

    We better get used to the fact that humans won't be piloting interplanetary spaceships, they'll just look at the computer charts and look nice in uniform.

    Anything requiring human intervention and control would be really bad news.


Leave a Comment