Space may be the ultimate frontier for many but it is a playground for a select few. It is a harsh environment and humans are ill-adapted to survive in such conditions without cumbersome life-support systems, which is why we turn to spacecraft to do our bidding in space.
Unfortunately, the same harsh environment also makes spacecraft design and operation excruciatingly difficult and prohibitively expensive for most entities to pull off the challenge successfully. History is littered with failed attempts by even some of the best-resourced nation states.
Despite the obstacles, many applications of spacecraft are already integrated into our lives. Weather predictions, international communications and simply navigating through the fastest route during our daily commutes all depend on spacecraft – and increasingly, satellite constellations orbiting at various levels around planet Earth.
Constellations reduce the cost of satellites by dividing their services across many smaller and lower-cost spacecraft. Starlink and OneWeb provide internet services to anyone using their respective constellations of small satellites. Similarly, Planet Labs images some 200 million km2/day, enough to snapshot the entire planet daily using a constellation of CubeSats, called Doves and SuperDoves, which would literally fit in a shoebox.
However, the vast potential of space is still largely untapped. The various planets, moons and asteroids of the solar system remain a highly underutilised resource, while our home planet is currently undergoing major climate and ecological upheaval due to over-exploitation in almost every domain. This must change and containing the costs of space exploration further is going to be the key.
At the University of Malta, things are being taken to the next level with the ASTREA and QUASAR projects. In collaboration with Blu5 Labs Ltd, a new class of tiny spacecraft clusters have been developed that allow very large constellations of 250g satellites to be mass-produced from commercially available off-the-shelf components without compromising much on reliability.
Constellations reduce the cost of satellites by dividing their services across many smaller and lower-cost spacecraft
A single launch can deploy an entire constellation, which promises to reduce costs dramatically. When given the cue from ground control, each cluster of eight units hierarchically divides into two, which then repel from one another electromagnetically.
Each half of the cluster reorients to maximise or minimise drag or lift until they reach the required orbital position. Then the process repeats until an evenly distributed constellation of individual satellites is achieved around the planet.
Each satellite can accommodate a variety of payloads and the applications are varied: ranging from communications to space weather monitoring, sensor networks or aircraft tracking.
A side advantage of this technology is that the problem of space-debris accumulation is completely addressed: besides the advantage of putting much less matter into orbit to begin with, the low-cost individual satellites may be economically placed at a low orbital height, which makes for a relatively short-lived stay in space.
After a couple of years, when their mission is complete, they will re-enter the atmosphere and are designed to disintegrate completely well before hitting anything on the ground. They would then be replaced with newer versions as necessary.
The next steps will be validating this novel Maltese spacecraft for various high-stakes missions.
Marc Anthony Azzopardi is an associate professor at the Faculty of Engineering and leads the ASTREA (R&I-2018-002T) and QUASAR (SUP-2023-02) projects, financed by Xjenza Malta R&I Technology Development Programme, focused on spacecraft development and qualification testing. Daniel Cumbo is an engineering PhD candidate specialising in spacecraft and space mission design.
Sound Bites
• Researchers have mapped and catalogued more that 70,000 synaptic connections from about 2,000 rat neurons, using a silicon chip capable of recording small yet telltale synaptic signals from a large number of neurons. The neuronal recording is a step closer to drawing a detailed synaptic connection map of the brain. In drawing these synaptic connection maps, scientists aim to discover which neurons connect to which and how strong the connections are.
• Researchers at the University of Cambridge developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source. This solar-powered reactor could be used to make fuel to power cars and planes, and could also be used to generate fuel in remote off-grid locations. Carbon capture and storage has been touted as a possible solution to the climate crisis.
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DID YOU KNOW?
• A satellite’s orbit is usually planned in such a way that it does not collide with other satellites. However, this is becoming more challenging as more satellites are launched.
• The first known crash of two satellites occurred in February 2009, when two communications satellites accidentally collided at a speed of 11.7km/s and an altitude of 789km above Siberia.
• CelesTrak’s calculations had expected these two satellites to miss each other by 584m.
For more trivia, see: www.um.edu.mt/think.