THE population of human-made satellites orbiting Earth has skyrocketed over the past 60 years. Launches nearly doubled from 2016 to 2017, and a significant contributor to this growth has been the development and implementation of small satellites that are easier and less expensive to build and more cost efficient to launch than conventional ones. Today, the hottest destination for these spacecraft is low-Earth orbit (LEO)—in the range of a few hundred kilometers above the planet’s surface.
Nanosatellites, a class of small satellites weighing between 1 and 10 kilograms (kg), have become increasingly popular because of their lower cost and ease of construction—made possible through standardization. Cube satellites, called CubeSats, are a common type of nanosatellite comprising a modular framework of cube-shaped building block units (U) that measure 10 centimeters (cm) per side, about twice the size of a Rubik’s cube. For comparison, the spherical Sputnik—the first artificial satellite in orbit—measured 58 cm in diameter and weighed 83.6 kg.
CubeSats typically comprise two main parts: a payload and a bus, the latter of which provides the structure, command and control, communication, power, navigation, and maneuvering systems for the spacecraft. Lawrence Livermore’s first involvement with CubeSats was developing optical imaging payloads for the Space-Based Telescopes for the Actionable Refinement of Ephemeris (STARE) project to monitor space debris. (See S&TR, April/May 2012, Launching Traffic Cameras into Space.) Since then, the Laboratory has continued to advance CubeSat technology and strengthen the institution’s space program. Through this work, Lawrence Livermore is embarking on new technological frontiers, from enhancing sophisticated optics and telescope designs to developing its own bus platform.
STARE-ing into Space
Consisting of derelict satellites, rocket boosters, and parts from spacecraft, pieces of space debris range in size from too small to be tracked to larger than a softball and can travel at speeds exceeding 25,000 kilometers per hour. Tens of thousands of these objects are tracked and considered lethal, and collisions, intercepts, and catastrophic failures continually increase the amount of debris. In 2009, for example, the inoperable Cosmos 2251 satellite collided with the privately owned Iridium 33 satellite over the Arctic at a closing speed of 12 km per second, breaking into more than 2,000 pieces of trackable debris. More recently, in 2015, astronauts aboard the International Space Station nearly collided with a fragment from a defunct weather satellite.