FTL telescope-satellites

Question

In this world, as soon as humans invent FTL, they launch "telescope-satellites" (I don't know what to call them) out in several directions. They travel at 10c, can communicate instantly with Earth, and are 10 meters in size (maybe bigger if someone gives me a reason for changing the size).

How many should be sent out? I'm currently thinking 6 but maybe there is a reason for more beyond just more is better.

What are the distances that they'd pause at to observe on their way out? They can't observe while traveling because the whole FTL thing would prevent it.

How far out would you want to limit them to? At some point you'd probably start getting diminishing results. For example the vertical ones would be outside of the galaxy long before the others. It seems that you probably wouldn't want/need to go past over 50,000 ly from the galactic plane because you could fairly easily image the galaxy as a whole at that point.

Answer 1

Call them Incredibly Long Baseline Array Sats, after the Very Long Baseline Array.

• They should be bigger than 10 m if you can afford it in your setting. The long baseline gives good resolution but not sensitivity, for that you need a decent antenna area.
• It will be necessary to determine the position of the array exactly to synchronize their data. Can you do that? How long will it take after the sats are in position? Going out very far might complicate that, too.
• There could be a series of experiments. Thousand AU. One lightyear. Thousand lightyears. Each will consist of new sats, larger and better than the predecessors.
• Some arrays may be positioned not relative to Earth but relative to the target of the observation. Say they meet an alien scoutship at some uninhabited star. Position sensor sats two lightyears from that system and watch it arrive. (That idea is from the Traveller game-)

Answer 2

FTL space-telescopes (after all, if we call Hubble a space-telescope, why not do the same for the FTL variety?) can be deployed in a number of ways depending on priorities of astronomers or Earth's government(s) especially our military services.

Firstly, to establish a series of long baseline observatories at a series of prescribed distances from the solar system to carry out a systematic survey of the galaxy. This has been discussed in another answer. However, observatories like these would also be useful to determine the location and scale of alien civilizations to anticipate any hostile action from alien civilizations. A kind of astronomical Distant Early Warning (DEW) system.

Secondly, there will be FTL space-telescopes launched in specific directions to conduct specific research programs. For example, observing the Crab nebula supernova which seen on Earth in 1054 AD. The relative age of the supernova is 952 years (as at 2016 AD). A FTL space-telescope would need to travel for 95.2 years at 10 c, to catch up with the light of the supernova event. The FTL space-telescope can move to positions where it can observe SN 1054 multiple times.

Astronomers will undoubtedly devise a whole suites of research programs to take advantage of a faster-than-light mobile observatory. The Crab nebula example was used as a reference for the type of research they might devise.

Interestingly there would a lot of scope for FTL space-telescope flying well outside the plane of the galaxy and carry out at overflight survey. This could a circumnavigation of the galaxy, at the distance the solar system is from the galactic centre, to map out the galactic habitable zone as part of a preliminary strategy for interstellar exploration.