Deep-space nanospacecraft: the challenges of bringing cubesats to interplanetary space
Space Travel Blog / UT Tartu Observatory (Slavinskis)
2022. g. 22. aug.
As developers of deep-space cubesats or nanospacecraft, we have noticed a technological gap in navigation. Typical deep-space missions use so-called deep-space networks, or DSNs, and radio frequency ranging for determining the spacecraft’s position. We propose to use optical celestial navigation by tracking Solar System objects – the Sun, planets, moons and asteroids – and triangulating the spacecraft’s positions.
The DSN infrastructure, maintained by space agencies, is expensive and a limited resource for our interplanetary ambitions, especially for an emerging class of fleets, nodes, pearls and swarms of interplanetary nanospacecraft. The Space Travel Blog post published by our co-founder Andris Slavinskis explains the difference between cubesats in low Earth orbit and in deep space as well as between conventional deep-space missions, operated by space agencies.
Without a deep-space network in our backyard, we are interested in looking for alternative deep-space communication and navigation solutions that would be scalable to tens, even hundreds, of nanospacecraft.
Deep-space navigation
Not only are DSNs used for communications, but also for navigation. Radio frequency ranging allows measuring the distance between the spacecraft and a DSN antenna. By combining orbital modelling with ranging measurements over time from multiple antennas, it is possible to determine the precise location of a spacecraft anywhere in the Solar System. Similarly clever tricks are used in the Global Positioning System, commonly known as GPS, whereby your smartphone uses signals arriving from multiple GPS satellites.
Radio frequency ranging requires transmitters and receivers, both artificially developed by humans. However, we have natural sources of location information placed around the Solar System. By using the old tricks of celestial navigation, we can develop camera-based autonomous systems that are capable of determining a spacecraft’s location from images including Solar System bodies. For example, a spacecraft can be aware of the Sun’s location at nearly all times. While in the Earth–Moon system (also known as cis-lunar space), we can use the location of Earth and the Moon in order to use triangulation and calculate the three dimensions of a spacecraft’s position. When leaving the Earth and the Moon behind, a deep-space-travelling nanospacecraft would need to rely on the images of other planets, their moons, asteroids and comets to complete the triangulation equation.
Read the full article on Space Travel Blog.