A CubeSat is a small satellite consisting of one or several 10x10x10 cm units, no more than 1.33 kilograms per unit. CubeSats can range from 1 Unit or “1U” to 12 Units or “12U.
“Spire’s LEMUR satellites are roughly 10x10x30 cm or 3U. CubeSats are known for being relatively inexpensive to build by using commercial off-the-shelf parts, and much less expensive to launch as secondary payloads than conventional large satellites. Initially designed for academia, CubeSats are being adapted for commercial applications, largely for Earth observation. Most CubeSats operate no higher than low Earth orbit. In October 2018, NASA’s MarCO mission captured an image of Mars from a CubeSat, the first deep-space experiment for these small satellites.