What is a CubeSat?
CubeSats are tiny box-shaped satellites that are mainly launched into low Earth orbit to observe the Earth, test new communications technology or perform miniature experiments.
In 1999, engineers at two United States universities came up with a set of specifications for a small inexpensive satellite that their space engineering students could learn how to design, make and send into space.
The basic CubeSat design is a cube 10 cm x 10 cm x 10 cm in size and is called 1U (standing for ‘one unit’). It is similar in size to a standard Rubik’s Cube. The mass of 1U is not allowed to be greater than 1.33 kg.
Cheaper and easier to launch
CubeSats have become popular, especially when it became even cheaper and easier to launch them into space from rockets that could carry a number of them at the same time. Their standard shape and size makes it possible to pack several together and push them from the rocket once in space using a spring-loaded dispenser. The record is 120 CubeSats deployed from a single rocket! NASA also regularly releases CubeSats from the International Space Station.
CubeSat form factors
Even though 1U CubeSats have a wide variety of uses, their size makes them limited, especially if a satellite is more complex and needs extra power or to control its attitude. Consequently, larger sizes with a range of form factors have become popular, such as the 1.5U, 2U, 3U, 6U and 12U CubeSats. Some can even be as big as 16U.
The only requirement is that their form factor has to be a long box shape so that they can be released by a dispenser in the same way as the basic 1U CubeSat. Currently, the 3U CubeSat followed by the 6U and 1U are the most common CubeSats.
CubeSat components are readily available
The standardised specifications for CubeSats makes it possible for technological companies to make standard parts that can be sold off the shelf. For example, at the CubeSatShop, there are over 90 products available including solar panels, communication systems, and attitude determination and control systems.
If you want a CubeSat (or any spacecraft) to point in a particular direction, such as towards the Earth’s surface to take images or make solar panels face the Sun, an attitude determination and control system (ADCS) is needed. The ADCS consists of attitude sensors that determine where in space the satellite is currently pointing and attitude actuators that rotate the satellite to the required direction. For a satellite orbiting the Earth, this system would be constantly in action to keep the satellite facing the Earth’s surface. An ADCS takes up quite a lot of room and helps to explain why most CubeSats built now are larger than 1U.
Uses for CubeSats
Over 1,600 CubeSats have been launched since 1999. In addition to university projects and experiments, they are increasingly being designed by commercial companies to be used in a wider range of purposes such as agriculture, forestry, energy, media and entertainment, civil engineering, traffic monitoring and archaeology.
Two CubeSats, MarCO-A and MarCO-B, were part of a mission to Mars in 2018. They were deployed to orbit Mars and provided a real-time communications link to Earth for the InSight lander during its entry, descent and landing when InSight was out of line of sight from the Earth. Both CubeSats were 6U in size and were also used to test how they could cope in deep space.
Sarah Kessans at the University of Canterbury is using a CubeSat to better grow protein crystals in microgravity when her CubeSat is in low Earth orbit.
In June 2022, Rocket Lab used its Māhia Peninsula Launch Complex 1 to launch a 12U CubeSat called CAPSTONE to orbit the Moon. Its 6-month mission is to test a special orbit, the near-rectilinear halo orbit (NRHO), around the Moon. This is in preparation for NASA to send a space station called Gateway into that orbit. As its name suggests, the Gateway space station will provide astronauts with a platform to more easily access the Moon’s surface.
Satellites – mini and very, very small
Satellites come in all shapes and sizes due to their different purposes and where they are positioned in space. For convenience, smaller satellites have been put into categories according to their mass. CubeSats usually fit into the nanosatellite category.
