Launching the SpIRIT satellite

CHRIS HATZIS
Eavesdrop on Experts, a podcast about stories of inspiration and insights. It’s where expert types obsess, confess and profess. I’m Chris Hatzis, let’s eavesdrop on experts changing the world - one lecture, one experiment, one interview at a time.

In June of 2020, science and engineering researchers at the University of Melbourne were awarded a $A3.95 million Australian Government grant to help develop cutting-edge space capabilities in Australia.

The funding from the Australian Space Agency's International Space Investment: Expand Capability grant opportunity will allow researchers to build a small satellite – called SpIRIT – to be launched in space by 2022, in collaboration with multiple Australian space industry companies and the Italian Space Agency.

Associate Professor Michele Trenti from the University of Melbourne School of Physics is the lead investigator of the SpIRIT satellite. Dr Airlie Chapman is a senior lecturer in mechatronics from the Melbourne School of Engineering at the University of Melbourne and co-investigator on the project.

Both Airlie Chapman and Michele Trenti sat down for a Zoom chat about their work with Dr Andi Horvath.

ANDI HORVATH
When you two are out and about in the public, do you get questions about space research, why is it important, why we need to understand what stars are doing or why we need to be out there?

MICHELE TRENTI
I think this is a great question. If you think about the history of humanity, exploring new frontiers has always been a key driver of our pursuit for knowledge and I think it reflects intrinsic curiosity of us as a species. Space today is the ultimate frontier for exploration. Also, everyone who has been out in a place far away from civilisation, I think has always been fascinated by looking up at the night sky seeing stars, planets and wondering what is our place in the cosmos. That's at least my own personal view on the matter, the part that took me towards being today at the University of Melbourne studying the universe and how we can build small satellites to help us with that.

ANDI HORVATH
Now, the Australian space industry is not something a lot of us are familiar with. I know we've got big dishes that examine what our skies are doing but tell us more about the Australian space industry. You mentioned satellites, do we have satellites that are Australian up there?

AIRLIE CHAPMAN
I think Australia's actually had quite a long, rich history in space exploration and been part of the space economy. It actually began probably in about the 1950s and 60s when Australian experts were actually involved in tracking the Apollo spacecrafts. Few people know this, but actually Australia was among the first to send out a sovereign satellite. In 1967 Australia became the third nation to design and launch a satellite into orbit, and it was actually launched from Woomera. There has been a bit of a hiatus over time, where we lost a little bit of our own enthusiasm for space, but more recently there's just been a huge explosion.

I think the Australian space industry has just crossed the five billion revenue mark, for example, and I think it's growing at about five per cent per annum which is fantastic in revenue, and employing about 10 per cent per annum in average growth as well, so the employment sector in supporting this industry over the last five years has grown a huge amount. We have lots of involvement in a lot of different industries that are supporting space exploration and involvement in satellites that have components that are built by Australian industry and Australian universities.

ANDI HORVATH
That's really exciting. Now, I know you two are involved in an Australian Space Agency international space investment program.

MICHELE TRENTI
It's very exciting to be part of this first call for proposals by the Australian Space Agency to develop a project that will increase Australia's presence in space. We have been awarded about $A4 million to design, build and launch in orbit a small satellite the size of a shoe box, about 10 kilos, that will both help Australian space companies to show to the world how competitive their products are as well as there's a satellite called SpIRIT, will help astronomers such as myself to study the cosmos because SpIRIT will carry onboard a sophisticated x-ray detector to spot cosmic explosions.

ANDI HORVATH
Now, SpIRIT's actually an acronym...

MICHELE TRENTI
SpIRIT stands for the Space Industry Responsive Intelligent Thermal satellite and these attributes represent three characteristics that we want to prove with SpIRIT. We want to have a satellite which is responsive, so it's capable of receiving commands very quickly from the ground and to alter its operation to respond to those commands. That's very unusual for small satellites the size of SpIRIT because generally those receive commands only maybe once a day when they pass over a ground station designed to control the satellite.

The second aspect, the intelligent attribute of SpIRIT, because we want to demonstrate that SpIRIT will have advanced onboard computing capabilities to take decision autonomously in particular with respect to strategies for optimally achieving these real-time communications with the ground in both directions; both receiving commands and acting autonomously and then as well as sending data down to the ground if something interesting happens. For example, if our x-ray detector onboard SpIRIT spots a star dying with a massive cosmic explosion called gamma-ray burst in a faraway galaxy.

The third attribute of SpIRIT, the thermal, represents the capability of the spacecraft to carefully cool and control the temperature of the instruments onboard the spacecraft, our x-ray detector. That's again very important because it will improve the sensitivity of the instrument and it will demonstrate capabilities that we are hoping in the future to apply to even more ambitious projects for launching an infrared space telescope in space which requires more aggressive cooling and very precise thermal control.

SpIRIT will be (1) a demonstration of the growing maturity of Australian companies that are partnering with us for the design and the fabrication of the spacecraft; (2) it will achieve some science on its own and; (3) it will be a pathway toward other space telescopes that we are hoping to build in this coming decade.

ANDI HORVATH
This is very exciting to hear about a shoe box size satellite of 10 kilos, but it's also a tiny little robotic spaceship. Airlie you're the mechatronic engineer, tell us more about that.

AIRLIE CHAPMAN
Well, I think one of the challenges happens is that when you start getting into smaller satellites everything has to be much more efficient. Your ability to - your limited number of amount of energy that you've access to, limited comms, it all becomes this big balancing act of payload capabilities and limited amount of resources, so it can be the case that if we can put more intelligence on our satellites, we can operate much more efficiently than relying solely on a ground station to be relaying our behaviour and this is really important when you have to have on the fly decisions. On the fly decisions can be, for example, in response to an unforeseen mission risk, so if something has been detected that isn't quite right, maybe the satellites getting a bit hot and you need to readjust before something gets damaged.

It also can be just in response to something that's exciting that's happened around you. Some of these space phenomenon that we really want to detect can be quite short lived, so the idea of being able to respond faster because the intelligence is onboard the satellite rather than solely having intelligence on the ground, is really critical. But again, this problem is challenging because it's not the way that we've operated for the last 60 years, it's a transition to relying much more for superior sensing, planning, decisions and actions to be taken onboard.

Now it's not going to be the case that we can rely on satellites to do everything, so it's also important to understand when there is a decision that has to be made, that you need to relay to the ground station and say; give me hand, give me some advice, what should I do now. So, really creating that optimised balance between decisions that can be made onboard and decisions that can be made on the ground, is really important.

ANDI HORVATH
Let me recap. This satellite is looking out into the cosmos gathering data intelligently but it's also looking back at earth; is that right?

MICHELE TRENTI
The satellite is looking back at earth in a couple of different ways. First, we can say it's looking back at earth because it has to regularly communicate with ground stations through its onboard radios. Second, the x-ray detector has been designed for astrophysics application, but here with SpIRIT we're really demonstrating the technology and so we could think about pointing a similar detector design for earth observations or for observing the nearby objects passing by, for example asteroids, and there are a few options for using this new technology that we are developing effectively. For example, in the context of asteroid studies, we could use x-ray observations for mineral prospecting, so we could help future assessment of opportunities for mining asteroids, for example.

ANDI HORVATH
Are there a lot of satellites already in the sky, and what stops them from bumping into each other?

AIRLIE CHAPMAN
Yes, there are quite a lot up there, but the benefit we have is there's quite a big volume of space that's around us. I think one of the challenges is that often certain places in orbit around the planet are much more valuable than others. Particularly lower orbits can be in high demand because the distances communication has to travel is shorter, and if you're trying to do earth observations, it can be a lot more convenient to be closer to the earth. Furthermore, it is a lot cheaper to actually get them into those kind of orbits. In addition, there's other things that come into play. For example, if your satellite is using solar power, being able to see the sun for most of the day is also important. That can narrow it down to certain orbits that are highly valued, and those can get a little crowded.

There is a negotiation that happens where you make sure to place your satellite in orbits that are not too cluttered, or not too close to others. But it is also important to then say - we have a way to say that once a satellite has reached its end of life we have a way of removing it from some of those valuable locations. Part of the satellite's mission design is also to have a de-orbiting phase which will allow the satellite to no longer clutter that valuable space creating an opening for other satellites to take it up, and also just removing space debris in general as it is obviously a problem if you have too many objects cluttering an environment, as they can collide with others. It's very important as a space community that we value the volume of space around us and have proper protocols and negotiations to make sure that we are all using it fairly.

MICHELE TRENTI
If I may add one more aspect of SpIRIT in this context. With SpIRIT we are aiming at demonstrating for the first time in orbit an innovative concept for electric propulsion off another satellite, that one of our industry partners is developing and testing on the ground at the moment. With SpIRIT we'll have the capability of slightly altering the orbit of the spacecraft which is, as Airlie mentioned, very important to readjust the orbit if there is a risk of collision or when we want to end the mission plunge SpIRIT down into the atmosphere where it will be completely burned up.

ANDI HORVATH
I think my science is correct; but satellites are essentially falling so, what is the lifespan of a satellite once it's been launched?

MICHELE TRENTI
The answer depends on three main factors. One, which is the primary factor, is how high is the satellite orbit, because the orbit will only decrease due to drag with the atmosphere, so the higher we are, the less dense the atmosphere, the less drag there is. Then second, the drag of course depends on the area of the satellite, so the characteristic dimensions of the satellite compared to the mass of the satellite, which gives us the energy that is in the orbit. If we have a massive satellite higher up, they will essentially stay up forever. If you have a small satellite in a low Earth orbit, they will decay very quickly. For example, a one kilo satellite launched from the International Space Station might live only for six months to a year before being completely burned up by the atmospheric re-entry. For SpIRIT, we're aiming at a lifetime of at least two years for operation, so we're designing a launch in orbit to give us probably five, six years of lifetime for the project.

ANDI HORVATH
I'd like both of you to comment on a day where you were surprised or delighted by this project.

AIRLIE CHAPMAN
I think we are in such a revolutionary time in Australia when it comes to space, so it's one of these instances that things are happening day after day and to have the opportunity to work on a project like this, is something that's really very critical to Australia. To be part of this, to actually say, the Australian Space Agency and with it the funding of the Australian people, are supporting this type of research and innovation in space is a huge honour. I think for me getting the acceptance of this type of funding was probably one of the big excitements of the project.

But this is also because the work that went into this project has been evolving over a very long period of time, so there's peaks that happen when you get these kind of fantastic awards, but then there's also this growing amount of knowledge that we have as a base. These great collaborations with industry have been wonderfully exciting. These great collaborations with other researchers have made it really... as an opportunity in the next two years. To see how far we can go with this type of project, is going to be something that I'm going to look really forward to sharing with the people in my community and with my fellow Australians.

I have always been quite passionate about promoting space in Australia. We have a wonderful space engineering course at our university now, and to be actually able to share with students that we are actively working on this as a university with collaboration with industry and our partners, is something that is really a testimony to how far we're going and how far we can go in the future.

MICHELE TRENTI
Yeah. I share some of the same excitement. In particular as an astronomer, I feel really privileged that the Australian Space Agency has selected as its first and only mission funded so far an astronomy space telescope project to support. Secondly, I'm really excited because this project, as you mentioned in the beginning, is part of the international space investment expanding capability stream of the Australian Space Agency funding. The international aspect for SpIRIT is really a strong collaboration with our Italian colleagues and in particular with the Italian Space Agency and Italian National Institute of Astrophysics, which will provide the main instrument that will be flown on SpIRIT, this advanced x-ray sensor called HERMES.

As an Italian I'm really really happy that this project will also promote bilateral co-operation between the two countries on advancing peaceful exploration of space and pursuit of knowledge.

ANDI HORVATH
Airlie, what inspired you to be a rocket scientist, if I can call you that?

AIRLIE CHAPMAN
Many children go through one of two phases. They either go through a dinosaur obsession or a space obsession. Sometimes both, but I was very firmly in the space obsession. I knew from a very young age that I wanted to do something to do with space, and as it evolved over time, I became very passionate about engineering and understanding how technology can support our ability to explore space. That drove me to want to learn more and more about it so I was trained as an aerospace engineer and I went and studied in the Silicon Valley of aerospace, which is Washington state in the US, to be able to explore more about what the promise was with space.

But because this is such a pivotal time in Australia's history, what drew me back to Australia was the fact that we are this growing - this growing nation now in space exploration and to be able to work on that cutting-edge end of research in Australia, is something that is hugely exciting and hugely rewarding. For me, what drew me was that initial fascination with space, what kept me was that fascination with engineering technology and how it can support developing our understanding of space and also the world we live in as we can look to ourselves from space as well. Then with the bright future I see, is being in this really exciting environment that we can keep on building our abilities as a nation that can collaborate with other nations as well as training future engineers, future scientists to continue to build this field.

ANDI HORVATH
Michele, what inspired you to be an astrophysicist?

MICHELE TRENTI
Looking up at the night sky and wondering what's out there. I was pretty set on this career path from when I was about six or seven years old and I started getting very very interested in understanding all the different types of stars and galaxies that we have in the universe. Then I followed that path for the rest of my education. I studied physics with a focus on astrophysics in Italy. I spent some years in the United States doing research, I've been in the UK at the University of Cambridge for a few more years and eventually there was this really exciting opportunity to join the University of Melbourne with a faculty position as senior lecturer; I took it and it has been really productive.

Australia is one of the best countries for supporting astrophysics research, it's really an area of excellence in the country especially in the field that I'm focussed on, that is the study of the first billion years after the big bang, the so-called epoch of reionization when the first light sources, the first stars and the first galaxies started illuminating the universe and lifting this cosmic fog due to neutral hydrogen absorbing the high energy ultraviolet light and so they start producing this ultraviolet photons ionising their surroundings and eventually by about one billion years after the big bang, the first galaxies have made the universe transparent again so we can study it in its full detail.

ANDI HORVATH
Next time we find ourselves gazing up at the stars on a clear night and we notice something moving across the sky and we think, oh, that might be a satellite; what would you like us to think about?

AIRLIE CHAPMAN
I would hope that you can think about it as a representation of how far mankind has come. That may be a little bit broad. But the amount of technology and innovation that had to go into getting that satellite up there to support us through communication, to support us in terms of scientific exploration, to support us in monitoring the world we live in, is just a fantastic achievement. I think we often don't reflect on how far we've come with our knowledge of science and technological development and that's just one representation that can just show how much we've achieved.

I would hope there'd be something of that and maybe a little bit of wonder. Maybe a bit of can I find out more, can I understand maybe what went into that technology, what is the next thing that's coming, what is that promise that will enable us to forward ourselves more as a society. I think it's always good to be inquisitive, always good to know a little bit more about the world around us, and I think satellites and space exploration is really that final frontier that we're pushing more and more into, and it's a great way to learn more about a really exciting area.

ANDI HORVATH
Michele?

MICHELE TRENTI
Putting up a satellite in space is incredibly challenging. The hardware has to work the first time without any possibility of making modifications, so that requires an incredible amount of problem solving, analytical skills, careful planning about long term consequences. We have clear examples with the thousands of satellites up there that as humanity can be really good at that. I would hope that all these skills and approach to challenges and problem solving could be applied to many other aspects of our society, which are really critical for our future and for future generations. Key challenges such as sustainability, climate change, planning for how we want our societies to be in the future, design of liveable cities. I think that what is being demonstrated with examples such as putting satellites in space, would be really wonderful to see translations into all these other aspects of humanity as well.

ANDI HORVATH
Associate Professor Michele Trenti and Doctor Airlie Chapman, thank you.

MICHELE TRENTI
Thank you for having us.

AIRLIE CHAPMAN
Thank you for having us.

CHRIS HATZIS
Thank you to Associate Professor Michele Trenti from the School of Physics and Dr Airlie Chapman from the Melbourne School of Engineering, both at the University of Melbourne. And thanks to our reporter Dr Andi Horvath.

Eavesdrop on Experts - stories of inspiration and insights - was made possible by the University of Melbourne. This episode was recorded on June 30, 2020. You’ll find a full transcript on the Pursuit website. Production, audio engineering and editing by me, Chris Hatzis. Co-production - Silvi Vann-Wall and Dr Andi Horvath. Eavesdrop on Experts is licensed under Creative Commons, Copyright 2020, The University of Melbourne. If you enjoyed this episode, review us on Apple Podcasts and check out the rest of the Eavesdrop episodes in our archive. I’m Chris Hatzis. Join us again next time for another Eavesdrop on Experts.