These proved both popular and semi-controversial. People loved them for the exact same reason as other people hated them; they made Makeb very accessible and all-but removed the risk of 'losing' the big fights, which were somewhat challenging when they were first released. I say this wincing at the mere memory of how bad the Cartel Mining Mesa used to be.
In 4.0, these Satellites were removed, and for good reason. Level-scaling pretty much ensured that they had next-to-no reason for existing in the first place; there was a cap on the maximum amount of Health, Armour, and Damage/Healing values which had never been in place before, and with the numerous ways of getting shedloads of XP a Player would more often than not be above the cap of 56 by the time they reached Makeb, let alone finishing it.
Additionally, since gear no longer mattered for Companions and they could have any role, it was no longer of import whether or not you had a Companion appropriately-geared for the fights they'd have to endure.
However, in spite of their comparative uselessness, it seems that they were missed by quite a substantial amount of people, because at some point in 5.0 - I recall it being a relatively-recent re-addition but I can't for the life of me even find the relevant Patch Notes where their return is mentioned - they made a return.
Being the curious sort, when I went to Makeb the other day to finally get around to working on the <Kill it with Fire> Achievement now that I actually had a character with burns I was willing to use regularly, I decided to indulge in using the Satellite just to see what it did.
As suspected, Level-Scaling has nullified the Bolster aspect. Provided that you reach the cap of Mastery, Endurance, and Power (which is attainable at Level 70 by completely removing most of your gear), your character only gains the 250% Exploration XP buff and the Healing Probes, both of which are nice to have, but shouldn't necessarily be the biggest selling-points of the Satellites in the first place.
Notice how I deliberately specified the things which your character gains? There's a reason for that. Companions benefit from this far more than any single Player does.
How, you might ask?
Well, you know how every time you go down to a Planet the Companion is synced perfectly to the Level-cap, so much so that they don't even say they're 70/whatever down to 56 but for all intents and purposes have always been Level 56?
The GSI Satellite does away with that. Your Companion is left at their highest present Level and thus has access to all their big non-scaled stats and numbers.
This basically means that you become immortal. Either your Companion is steamrollering over everything in its path (and creating far more Threat than you could ever hope to even as a DPS), or it's outhealing every bit of damage done to you by an absolute payload (and again creating vastly more Threat because of the passive healing Threat and because it'll still deal damage when it sees no reason to heal you), or your Companion is literally an Immortal Juggernaut of a Tank.
Which means that everything on Makeb is an absolute walk-in-the-park as long as you're under the effect of this Satellite. Since nothing can even so much as touch your Companion, there is virtually no risk of death unless you happen to get knocked off a cliff or your Companion is unable to either see you or the target you want it to kill because of reasons.
Of course this isn't even mentioning the PvP aspects of this. Say you decide to go onto a PvP Instance just to see if you can get a few more kills for your Achievements.
You yourself don't find anyone, but are instead found. Let's say while mounted. Your opponent has the drop on you while your Companion is tucked safely away from harm's way. Unless you are dismounted by the force of the attacks and your instantly-summoned Companion is very quick-on-the-draw with its Healing (if it's even a Healer at all) you're pretty much dead in the water instantly.
On the other hand, you may get locked into a stalemate of constantly being unable to negate either Companion's healing, since of course you yourself can't defeat their Companion, and nor they yours, since being Level 56 trying to tackle a Level 70, every ability will miss or be resisted.
So basically, the return of the GSI Satellites, while welcome in some centres, is quite a ridiculous phenomenon. It's practically unnecessary for several Player characters and it presents the "Companions are over-powered" crowd with far more fuel than they know what to do with.
Whilst the Satellite is of course optional, I do think that the Companion aspect of it should be tweaked, even if only to address the aforementioned concerns regarding a Companion's usage in Open World PvP. That said, I do acknowledge that this isn't a frequent occurrence to begin with. In some ways, this Satellite could be considered a soft-exploit if used solely to gain an unfair advantage over other Players in such theoretical battles, which I don't see as being acceptable in the slightest.
Still, it's interesting to see the Satellite back for whatever reasons. I am very curious to know just how many people wanted to see it return.