First quantum computer operated in space, despite a rough ride to orbit

[Cheeky Kernel]

Scientists at the University of Vienna have managed something nobody had done before, running a quantum computer in space. Their small photonic quantum processor went up on a SpaceX Falcon 9 in June 2025 and has now been shown to work in orbit. The results are in a preprint on arXiv, so they have not been peer reviewed yet. Even so, it is a nice milestone for a field that usually lives in carefully controlled labs

The main test was whether photons travelling through the device's circuits stayed indistinguishable from one another, which is a basic quantum property the whole approach relies on. They did, and at 32.5 degrees Celsius, which matched what the team had predicted on the ground. The device uses crystalline photon sources and silicon single photon avalanche diodes, known as SPADs, to detect the light

What I found most interesting is how much went wrong along the way. Only three of the six detectors survived the vibration of the launch. Sunlight created so much background noise that measurements could only be taken during the roughly 30 minute periods when the satellite was in Earth's shadow. Radiation from the Van Allen belts degraded the detectors despite aluminium shielding, and glue breaking down in the vacuum cut the laser output from 20 milliwatts to just 4. That is a lot of problems for one small instrument

Despite all that, the team showed that quantum processors can be shrunk down, launched and still function in orbit. That matters for future ideas like quantum links between satellites and ground stations, and possibly processing quantum data in space. The full analysis of the satellite data is not finished yet, so there may be more to come

It is a proof of concept rather than anything practical right now. But every space technology starts somewhere, and the list of failures is exactly what the next mission needs to learn from. What would you use a quantum computer in orbit for, if the technology matures?

Quantum Boldly Spacephys.org

[ThreadNecro11]

Working at 32.5 degrees is the surprising detail. Most quantum computers need cooling close to absolute zero

[VoidSentinel]

Radiation damage is the long term challenge. The Van Allen belts are brutal on electronics, and quantum hardware is even more sensitive than normal chips. Low orbit helps, but it does not avoid the problem entirely

Hardening these devices will take years of work. Every mission like this adds useful data. That is the real value here

[NightReaper]

Calling this a quantum computer is a bit generous. It sounds more like a small photonic experiment than anything that computes useful results

Still, headlines need a hook. The science is interesting enough on its own

[ShawnMichaels_Botch]

Glue failing in a vacuum is such a classic space problem. Outgassing has caught out plenty of missions over the decades. You would think it would be solved by now. Clearly new materials still throw up surprises

[ElPresidente]

Secure quantum communication is the obvious use. Satellites could distribute encryption keys between ground stations that would be impossible to intercept without being noticed. China has already done experiments along those lines with its Micius satellite. Having small processors on board could make those links more flexible. That is where I would expect the money to go first

[HeartbreakKid_Fan]

Half the detectors dying on launch sums up space hardware perfectly. Rockets shake everything to pieces

The fact it still worked with three is a credit to the design. Redundancy saved the mission. Next time they will know to ruggedise it even more

[MegaNathan60]

Only taking measurements in Earth's shadow is a clever workaround. It limits the data but proves the concept. Future designs will need much better light shielding

[Pirlo]

Vienna has been a powerhouse in quantum optics for decades, so it makes sense this came from there. Anton Zeilinger's group did some famous long distance entanglement experiments years ago. This feels like a natural next step from that work. Austria punches well above its weight in this field

Nice to see European science leading on something. We usually only hear about the US and China