This is a follow-up to an as of yet unanswered question: What would the local effects/affects be of a ring spinning near luminal velocity?
If you can, please take a look at this question as well!
Contrasting most any StarTrek episode Spock is peering into his sensor console visor, exclaiming that he has never seen insert technobabble here before.
Our Colony Ship has arrived at its destination solar system (yellow dwarf star), and is making course corrections to make orbit with the target planet, still months away. Meanwhile The object in my other post has been detected. Considering the ring spinning at luminal speeds(the "Artifact") is only a mile (aprox) in diameter. And the colony ship is on the outer reaches of the system, (~4-5 billion miles? can be any reasonable distance). The Artifact is in an independent orbit around the star, at around 0.5 AU. What would make up a realistic "Sensor Array"?
What would be it's capabilities and limitations?
What would take hours to analyze, and what would be known instantly?

These are the constraints of the universe as well as I can make them.

  • Earth timeline future of within 100 years.
  • Fusion power / propulsion exists and is efficient and well understood.
  • Antimatter power / propulsion exists but is inefficient and still being developed.
  • Quantum Computing is a thing and well understood.
  • Limited AI is present but contained. (AI is NOT a threat... the three laws work, but due to human self imposed limitations, AI/ROBOTS are limited in there allowed functions).
  • Robots/Robotics are allowed but limited to activities only deemed too dangerous for humans. Or where human 'inconsistencies' or bias would be detrimental.
  • The Colony Ship is equipped with technology that would give it the best chance of success, joint venture of government, military and civilian.
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    $\begingroup$ What is the sensor array supposed to sense? The question doesn't say anything about what are the items of interest; that is, what do they want to find out about their new environment? (And why on Earth did they wait to power their sensor array until they were within a few tens of astronomical units from the target star? I would have expected them to start accumulating data from much farther out.) $\endgroup$
    – AlexP
    Commented Nov 19, 2021 at 14:59
  • $\begingroup$ @AlexP That's the essence of the question. the obvious purpose of a sensor array is to "Sense everything you can sense". Thus my question What can we since? What components makes up a sensor array? ex: in this one of the first would be a telescope of at least Hubble class or better? The scenario is still being refined. Of course they would be gathering as much data as possible the whole time $\endgroup$
    – Gillgamesh
    Commented Nov 19, 2021 at 15:08
  • $\begingroup$ Sensing everything is a tall and impossible order. I'm assuming that in your world folks aren't tracking every stray helium atom that leaves earth's atmosphere. There is a trade off of cost, coverage, and sensitivity, sensors that aren't worth the cost don't get built, and sensors that can cover a large area do so at the expense of sensitivity. In short sensors exist with a purpose. What are your folks trying to sense? $\endgroup$
    – sphennings
    Commented Nov 19, 2021 at 15:40
  • $\begingroup$ @sphennings Again...This is exactly the question. Given the setting described, and technology level. What types of Sensors would likely exist? What kind of sensors would go on an interstellar ship? For that matter what kind are on an Aegis destroyer that I don't know about? Not an easy question. Monetary cost is the lowest factor as described. Would sensors used inside a particle accelerator in some form exist? Or would they even be useful? If they were being bombarded by neutrinos would they know? Are Neutrino detectors likely to be developed that don't have to be miles underground? $\endgroup$
    – Gillgamesh
    Commented Nov 19, 2021 at 15:58
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    $\begingroup$ Perhaps phrasing the question. What instruments would make up a reasonable but comprehensive sensor array in an interstellar spaceship ? $\endgroup$
    – Gillgamesh
    Commented Nov 19, 2021 at 16:01

1 Answer 1


I am going to make an assumption, based on your technological constrains, there is no FTL of any kind, including travel, communications and emissions.

When you said "And the colony ship is on the outer reaches of the system, (~4-5 billion miles? can be any reasonable distance)" may be a little too small of a number. This places it equivalent to the orbit of Pluto. They would probably be making observations long before that, many of which they would actually make before leaving Earth.

Now, I will assume your distance of 5 billion KM for this. Your ship would be equipped with enough sensors to successfully detect a the needed resources to determine where to set up the colony. These sensors would include spectroscopy in many wavelengths ranging from low range radio waves through deep infrared, visible light, ultra violet, x-ray and gamma. They will have optical and radio telescopes. in 100 years or more, they may also be able to use particles, such as muons, bosons and MAYBE some exotic particles to assist in chemical analysis' of there target colony. They may even have some sort of rudimentary ability to use gravitational lensing to assist in detection or carry some ability to detect gravitational waves, assuming the technology was miniaturized enough at this.

These are a sort of passive form of analysis. They would need to position themselves so the target would lie between the star and themselves. That can take some time to get into an optimal position to allow for analysis. Less reliably, they may also have a small suite of active detection systems, such as LiDAR, RADAR or microwave sensors. At this distances, it will take light ~9.25 hours to make the round trip. It would be very difficult to make a good lock on your object at these distances and, due to various reasons, will take a very long time to gather enough data to overcome background noise.

Now, just because you have all these sensors, doesn't mean you can do anything with all this data you will be receiving. You will probably have very large banks of super computers, maybe even super quantum computers. Even with 100 years of technological advancements, it will take some time to gather enough data to analysis it to tell the difference between useful data and noise.

Now, for timing

Observations on certain wavelengths can be near instantaneous. Optical, radio and microwave observations (not active detection) will tell you what it looks like based off the energy it reflects from its star and what energy it produces and releases itself. Give it a little time for the super computer to analysis it over the wide wavelengths of observable light and you get a picture of what it looks like. This wont tell you much more than that.

Your active sensors can constantly bombard the object with energy from across the spectrum, but it will take >9 hours to get returns, and maybe several hours to several days to analysis the data. From this you may get more data about composition.

After making appropriate maneuvers, you can get this object aligned for your spectroscopy sensors to have a look. This can get a lot more data such as chemical composition, maybe structures below the surface and a better understanding of its mass and impact on the star itself. Then all that data then needs to get processed by the computers. This could take weeks to months to get in the right position.

To sum it up, immediately, you know there is something there, and its SCREAMING in radio frequencies, and probably also in x-ray. You probably already knew this prior to traveling. It would take days for your active sensor to look at it. It may also take days for the spectroscopy to analysis it as you should have know it was there and had long ago positioned your ship to look at it, once you were close enough to make observations.

  • $\begingroup$ "may also be able to use particles, such as muons, bosons and MAYBE some exotic particles to assist in chemical analysis'" Can you provide a google search phrase or reference where I can break this down further? $\endgroup$
    – Gillgamesh
    Commented Nov 19, 2021 at 16:08
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    $\begingroup$ The one type I can think of off the top of my head is en.wikipedia.org/wiki/Neutrino_detector . Right now these types of detectors require massive arrays and buried deep under ground. Assuming 100 years or so of advancements, there could be some miniaturization of such technologies. This type of detector could reveal some information that present detectors cannot analysis. There is detection of charged particles from the star analysis. sciencedirect.com/topics/physics-and-astronomy/… is a type we presently use. Could be more useful in 100 years $\endgroup$
    – Sonvar
    Commented Nov 19, 2021 at 17:43

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