Developing the Sun
In NMS, instead of the planets revolving around the sun, the sun revolves around the planets.
But fixing that problem would involve adding ‘planet orbital physics.’
Would that unfortunately be just way too much to ask for? 
Hmm…
Orbital physics is already demonstrated by the fact that the sun rotates around the planets. And we know that ‘planet orbital physics’ existed in the game at some point before release, because HG stated that it was removed due to it confusing the early playtesters. 
It was for a similar reason that snakes were removed before release, as they proved “totally overpowered to the player,” to the playtesters. 
So who knows, maybe the developers can get it right, so that it’s no longer an issue, or maybe it never really was much of an issue, but the whiny playtesters made an issue of it, and so they could just bring it right back.
But no, chances are it was the developers, as they were just so hard-pressed for time back then. So I remain hopeful. But until then, we have to work around quirks like an orbital sun, which appears easy enough, but it’s just important to know about things like that, when developing the Sun.
The other thing important to know is that what we presently see as a sun is only the light itself, but close enough. The actual star is not present in-game. In other words, they never built the actual celestial body. Or you could say that it’s kinda there, it would appear as such well enough, and that’s all that matters.
But…
Building the sun is like building any other planet, only the immense size and powerful visuals change. 
Reaching the sun could be as simple as flying some distance to it, but no further at a risk of heat, radiation and ‘infinite insanity’ or “death by psychological incapacitance,” before even “death by extreme heat and extreme radiation,” and then harvesting some resource like Cosmic Energy as a purpose for going that far.
But it all boils down to one question…
@sheralmyst: What was it about the sun that indicated to you that you weren’t flying any further?
Do we know for an absolute certainty that our actual ‘star system playing area’ (or “radius,” or “bubble”) has been limited by the developers?
If so…
- How far?
- Why, exactly?
- Can they expand it?
This is important, because the answer to that question determines how to proceed.
If limited, then one question would surface…
Why would they limit this playing area?
- Would it be due to hardware limitations? (Example:)
- Would it take too long, or too much RAM, to load in?
Present Opinion…
I don’t think ‘hardware limitations’ or RAM are the main issue here, because we know how NMS works with procedural generation, everything we see loads in as we progress, except basic functions and a few other details, which load in when we load up the game, further loading in when we enter a star system, meaning as we proceed forward, loading in only as far out (at any given moment) as our hardware and RAM can support, and our quality settings are set to allow. This is an intense process, but with the right optimizations, “Voilà!”
So…
If limited, I’m led to believe that perhaps…
Our actual ‘star system playing area’ (or “radius,” or “bubble”) has been limited by the developers to prevent us from reaching the actual sun, the ‘representation of our sun’ (or “lightbox,” or “ball of light”), because it’s nothing more than ‘light itself’ (or ‘a source of light’) with no actual ‘playing surface’ (or ‘visual surface’), as they never developed the sun for up-close encounters.
However…
IF our actual ‘star system playing area’ (or “radius,” or “bubble”) has NOT been limited by the developers… And/Or IF there is no need for them to do so, such as hardware limitations or RAM… Then…
Developing the sun could be as simple as building another planet, this time well oversized than usual, and with a particularly powerful display of visuals, such as with the potential of massive solar flares, graceful eruptions of solar material, and even enormous sunspots, raging with a great ferocity and immense hunger.
Reaching the sun could be as simple as flying some distance to it.
Of course…
Compared against the Sun, this dot is our Earth → •
Summary
Photo By NASA Goddard Space Flight Center, July 30, 2015.
So…
Could reaching the Sun really be as simple as flying to it?
Of course — with enough patience, and space tacos. 
But careful, not too close, or…
Death Quote
“Life is eternal, and love is immortal, and death is only a horizon; and a horizon is nothing save the limit of our sight.” — Rossiter Worthington Raymond, Mining Engineer
So we man our telescope at the local space station or our freighter observatory and observe the beauty and immense power of an absolute eternity on the verge of collapse into a “Black Hole Sun” that we call life.