Quantum technologies are already revolutionizing life on Earth. But they also have the potential to change the way we operate in space. With the United States, China, and Europe all investing heavily in this area, these changes are likely to be with us sooner rather than later.
So how will quantum space technologies make a difference?
Now we have the big picture thanks to the work of Rainer Kaltenbaek at the Institute for Quantum Optics and Quantum Information, Austria, and colleagues across Europe, who have charted the future in this field. and exposed the advances that space-based quantum technologies will make possible.
As quantum computing and quantum communication grab the headlines, Kaltenbaek and his colleagues point out that other quantum technologies are expected to have equally impressive impacts. Take for example atomic interferometry with quantum sensors.
These devices can measure with unprecedented precision any change in motion of an orbiting satellite when rocked by tiny variations in the Earth’s gravitational field. These changes are caused by factors such as the movement of cooler, denser water flows in the deep ocean, flooding, movement of continents, and glacial flows.
This is why these types of quantum sensors will pave the way for a new era of Earth observation. These studies will reveal the hard-to-observe effects of climate change on deep ocean currents, how stresses build up on continents as they move, and help us better understand the geology of the Earth. âSpace-based quantum sensors will allow better monitoring of the Earth’s resources and improve predictions of earthquakes and the adverse effects of climate change, such as droughts and floods,â said Kaltenbaek and colleagues.
Better quantum clocks are also expected to become influential. The key technology here is not so much the ability to keep the time as the ability to transfer that information to another location with great precision. This ability will lead to arrays of space clocks that are synchronized more precisely than anything in existence today.
Timing networks are already considered fundamental – global navigation satellite systems, such as GPS, are good examples. And better timing will allow for more accurate geolocation services.
But this is only the beginning. An important application will be to create synthetic aperture telescopes for visible light.
The idea here is to record the arrival time of light waves at two different places, then calculate an image of their source, like a distant star. The resolution of this technique corresponds to the resolution of a conventional telescope with an aperture equal to the distance between these points, which can be several thousand kilometers apart – hence the term synthetic aperture.
But visible light has a wavelength measured in nanometers rather than meters. This requires much more precise timing measurements to record their arrival, which the next generation of space-based quantum timing devices should enable.
These types of synthetic aperture telescopes will be much more sensitive than anything we can build today, potentially allowing astronomers to study planets around other stars in great detail. Space gravitational wave observatories should also benefit, allowing them to pick up weaker signals from stars of colliding neurons and their ilk.
In the short term, the most important benefits of quantum space technologies will come from secure communications. A well-known application of quantum theory is to allow the transmission of information in complete security.
In 2016, China launched Micius, the world’s first quantum communications satellite. It has already demonstrated secure video calling from continent to continent. Europe and the United States are well behind in this area, but are expected to follow suit, linking terrestrial quantum communication networks to those in space and ultimately enabling a global quantum Internet.
Of course, all of this will require a lot of planning, a lot of cooperation and a lot of funding. Europe has committed significant funds to future quantum technologies, China is ahead of the game in space quantum technology while the United States lacks focus in certain areas.
This will have to change if it is to regain leadership in these areas.
Ref: Quantum Technologies in Space: arxiv.org/abs/2107.01387