Norn gives a public lecture on space situational awareness at Tartu Observatory

On 10 August 2026, Norn gave a public lecture at Tartu Observatory in Tõravere on space situational awareness. The talk was open to anyone who wanted to attend, and it was built for a mixed room: students, observatory staff, local engineers, and people who simply follow what happens above them.

The through-line was simple. Europe needs to see its own orbits, decide what to do about what it sees, and do both without depending on someone else's catalogue. That splits into two problems, and Norn is building one product against each.

What space situational awareness actually is

Space situational awareness is the discipline of knowing what is in orbit, where it is, where it will be, and what that implies for the things you own. In practice it is three layers stacked on top of each other: measurement (sensors that observe objects), cataloguing (turning observations into orbits and keeping them current), and decision support (turning orbits into actions an operator can take).

Most public conversation about the topic stops at the first layer, usually with a chart of how many objects are up there. The interesting engineering, and most of the operational cost, sits in the layers above it.

Conjunctions

A conjunction is a close approach between two catalogued objects. Screening produces a conjunction data message when a predicted approach crosses a threshold, and an operator receives them continuously, day and night, across every satellite in the fleet.

The lecture covered what those messages contain and what they do not. A conjunction data message carries a predicted miss distance, a time of closest approach, and covariance describing how confident the prediction is. It does not carry a decision. The probability of collision derived from it is highly sensitive to covariance quality, which is itself a function of how well the objects were tracked. Poor tracking inflates uncertainty, inflated uncertainty produces alerts that look serious and mostly are not, and the operator ends up reacting to the sensing quality rather than to the orbital environment.

The consequence is a signal-to-noise problem. Operators receive far more alerts than there are genuine risks, and the ones that matter are buried among the ones that do not.

Collision avoidance

The second half of the problem is what an operator does with an alert. A collision avoidance manoeuvre is not free. It costs propellant, which costs mission life. It costs a service interruption, which for an Earth observation or communications operator has a direct revenue value. It costs analyst hours, and it costs the follow-on work of re-planning the mission timeline around a changed orbit.

The talk walked through this as a decision problem rather than a physics problem. Given an alert with imperfect covariance, an operator has to weigh the cost of manoeuvring against the residual risk of not manoeuvring, under time pressure, repeatedly, across a fleet. Regulators increasingly want that reasoning documented. Insurers increasingly want it too.

That framing set up the two products.

Cadence

Cadence is Norn's conjunction cost and compliance analytics platform for satellite operators. It sits on top of the alert stream an operator already receives and answers the operational question: what does this alert cost us, what does acting on it cost us, and can we show our work later.

It attaches a cost model to conjunction events, tracks manoeuvre decisions and their propellant and downtime consequences, and produces the audit trail that regulatory and insurance conversations require. Cadence is in private beta with a cohort of LEO operators across commercial, defence, and Earth observation segments. Norn was shortlisted as a bidder in the ESA EXPRO+ procurement behind the platform.

The lecture used Cadence to make a narrower point: better decision support extracts more value from the catalogue you already have, without a single new sensor. That is the cheapest improvement available to the sector, and it is not fully harvested.

Photrak

The other half of the problem is the catalogue itself, which is where Photrak comes in. Photrak is an orbital pulsed laser rangefinder targeting centimetre-precision tracking of space debris. Where conventional radar and optical tracking leave metre-to-kilometre scale uncertainty on many objects, laser ranging measures distance directly and tightens the covariance at the source.

Tighter covariance changes the economics described above. Alerts that currently exist because the uncertainty ellipsoid is large stop being alerts. The manoeuvres that remain are the ones that were actually warranted. Fewer false alarms means less propellant burned, fewer service interruptions, and longer missions.

Photrak is the subject of an EIC Pathfinder Open submission coordinated by Norn with Laser Zentrum Nord and LC Innoconsult, spanning three EU countries. Its ranging capability is also the foundation for the sovereign orbital catalogue product on Norn's 2028+ roadmap.

The sovereign argument

The closing section addressed why any of this needs to be built in Europe when catalogues already exist elsewhere. The answer given was neither defensive nor political. A catalogue is an input to decisions that affect European assets, European services, and European liability. Inputs that critical should be produced under the law of the jurisdiction that depends on them, on infrastructure that jurisdiction controls. Norn's position is that the data, the analytics, and the hardware that produced them should all sit on European soil.

Discussion

The questions afterwards were good, and several of them were sharper than the talk. They ranged across the accuracy limits of laser ranging on uncooperative targets, how operators actually behave when alert volume exceeds analyst capacity, what the long-term debris growth curves imply for LEO constellations, and how a small company positions itself between institutional programmes and commercial operators. The discussion continued past the scheduled end.

Acknowledgements

Thank you to Tartu Observatory for hosting, and to the staff who arranged the evening and stayed for the discussion. Tartu Observatory is part of the University of Tartu and one of the partners behind ESA BIC Estonia, the programme Norn entered in July.

Thanks also to everyone who came out to Tõravere on a summer evening to hear about covariance ellipsoids.

What comes next

Norn intends to keep doing public talks of this kind. Space situational awareness is one of the few technical fields where the public interest is genuine and the public explanation is thin. If you would like Norn to speak at your institution or event, get in touch at hi@nornlabs.eu.

Related reading: Norn selected by ESA BIC Estonia (3 July 2026).