Was the planet shielded before David arrived?

It might also be possible the planet was never exposed to the pathogen before and thus was unable to hold it off. Whomever designed and created it (the shield) din't know or expect a pathogen bombardment.

The planet was not shielded from bombardment. David’s bombs got through just fine.

It’s entirely possible that Engineer technology can shield a planet from long range prying eyes. Why not. It would answer the question as to how the company missed it on its long range scans.

The juggernaut is built using advanced alien technology. It doesn’t have to worry about trifling matters such as atmosphere getting in its way. By the way, it was not FTL inside the atmosphere. If it had been, it would have disappeared in about 10 microseconds. 1/4000th of a frame of video.

We don’t know much about Engineer society. It’s possible that they have various castes and ethnicity scattered about the Galaxy.

Roger G:

Maybe the Engineers have developed in different ways like humanity? We started in one place and share most of the genes but developed in a different way so people around the world look different depending on genetics and maybe the Engineers are the same? This could mean that there are different kinds on different planets. At the same time the smaller Engineers maybe created the big ones to be guards and the big ones left because of something (maybe a disagreement of some sort).

You had one Engineer on LV-223 and some on Planet 4, maybe they are more spread out than that? Mankind can go to the moon and if we accept that the Engineers are more advanced then they might have spread to different places like a super-advanced version of the colonization in AC. I totally understand why you're wondering about that but this could be a possible explanation.

Hox is right that we don't know that much about the Engineers. Prometheus scratched the surface while Alien Covenant got rid of them except for that short scene. It was a pity how they treated them in Alien Covenant. They should have been given more screen-time, maybe it was the studio effing up again.

Earlier scripts had a planetary shield that Covenant had to destroy.

In the film David says the storms shield the whole planet - sometimes for months at a time.  If they were scanning while the planet was shielded - they'd miss it.

Is it really so necessary to cut out all the interesting details from the film? David has already said that storms last for days, weeks, months. Wasn't it possible to add details? The interesting details about alien world! No, it's better to burn screen time on annoying Tennessee instead! [sacrasm]After all, his hysteria aboard the Covenant undoubtedly looks more attractive to viewers than information about an alien world[/sarcasm].

Leto: The same could be said about most of the characters to be honest. Not sure why you single out Tennessee like that but maybe you just gave an example. He had the same problem as most of the characters, he had no well-defined personality. Unfortunately to me at least he was just a guy in a hat. I don't blame the actors, the script probably lacked or that they cut out interesting character-parts.

No. Tennessee is not just an example. We can understand that Tennessee is worried about his wife and is in a hurry to establish connection to the planet surface. But the presentation (and direction) is simply unfortunate. Instead of a person who goes crazy with anxiety and goes to extremes, we get a point of irritation. Instead of a decent husband and a space colonist - just an asshole shouting: "Yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeehaaaaaaaaaaaaaaaaaaaaaaaaaaaaaw"

His wife - Faris, btw, the another annoying character in the AC. First, she hysteria over the radio, then dooms her friend to death, then fucking blows up the shuttle. I'm pretty sure Ridley knew about the characters problems in Prometheus, but he said: "They hate stupid annoying characters - give them stupid annoying characters!"

Leto:

I agree that he should have reacted in a different way but then maybe people act different under pressure. Faris was kind of alright I think, at least she had some sort of personality, she was able to handle her thing until the monster showed up and she panicked. She was poorly written compared to the characters in the first three but compared to many of the characters in the movie I think that she did OK.

You mention the kind of hysteria but remember that she had just seen that thing bursting out and she freaked. Besides it chased Karine so it was surely lethal, no wonder why Faris panicked.

"They hate stupid annoying characters - give them stupid annoying characters!"

LMAO! That was fun but then how do you explain Prometheus? In a podcast they discussed the alien franchise and there they discussed the prequels and according to a documentary that they commented on Ridley seemed most concerned with getting it to two hours to get more showings. Even if the actors are alright, then so much can get cut out so they look like idiots in the final movie even if they are capable of doing good work. Both prequels suffer from characters that look like idiots but also if you look at an extended cut of Prometheus they dont look as bad. To me it seems that they cut too many scenes that make sense and that is either because of Scott and his bizarre fixation of cutting them down to two hours or the studio bosses having a messed up prioritization, I don’t blame the actors.

I think David's bombs got just fine because he was welcome, all the engineers gathered to see his arrival, the docking ship was ready for him. Somehow his arrival was known to the engineers.

I remeber there was a hypothesis that planet was shielded and that was the reason David could not leave with another Juggernaut from the undergound hangar, the ones seen in a deleted scene. He was not able to deactivate the shield.

But then we see the Covenant shuttle and the lander don't have any problems with any shield.

I am not sure if they missed the planet or the fact that it is habitable. Have to watch it again.

Regarding the Shield then YES this was the Original Idea the Planet was Protected by Floating Technology at the Planets Poles that we assume is what Cloaked the Planet, but Certainly Prevented the Covenant Rescue Mission from taking Place until it was DESTROYED.

This was NOT included in Alien Covenant the Movie and instead its the STORMS that maybe Cause the Problem.   But we cant RULE-OUT that the Planet has some kind of Cloak that MASKS what can be Detected from FAR OUT.

The Scorpion Ship acted as some kind of Border Control and when this SHIP was DESTROYED/DISABLED then it appears it RENDERED the Engineer Ships from being Unable to Leave the Planet..  but we cant Conclude this in the Theatrical Cut as the Scene of the Hanger with Multiple Juggernauts was removed.

Regarding the Silly Mistakes then a LOT of these Errors of Judgement and Stupidity are Plot Devices to ALLOW for a Certain THING to be shown or Happen.   Sadly some Stupid Errors can be Rectified with a Reason and Good Thought such as STUPID ASH for allowing Kane on the Nostromo (which we had the Reason latter Special Order 937 so that was CLEVER Writing).  But NOT every such Error of Ways for a Plot Device are as WELL Thought Out and Written.

The Drafts sometimes have more Detailed and Better Reasons for some Silly Errors made by the Characters.

As for Faris and Blowing Up the Lander, i think she was in Terror and Panicked and i would SAY she is NOT really Military Trained... and i think it was a Good Plot Device.

He Ha Super Alien you must Wrote that at the Same Time as i was doing my Reply ;)

The Urns did seem to HIT a Barrier that was OVER the Plaza, maybe it was a SHIELD.  But it Offered Little Protection.

I think the Engineers were Naive in their Technology and Protection of their Worlds, it would appear they had FELT as they Controlled the LEVEL of Advancement of the Worlds they VISIT they would ASSUME that a World that is Abandoned would NEVER see its Inhabitants be able to ADVANCE to become a Threat.

They maybe also are Naive to think that EVERY one of them Follow the Ways of the Engineers and so have LITTLE CONCERNS that another Faction of their Species would EVER come and USE their Technology against its OWN KIND.

And so maybe they NEVER really deemed it Necessary for Stronger Protective Measures.

Space is BIG

I refer you all to Douglas Adams and what he had to say regarding the bigosity of space. :D

Now, even with drones, probes and massive telescopes...lots of things can be hidden, say entire swathes of the galaxy we cannot see because nebulas block line-of-sight.

Probes, well say they sent out a few hundred...factor in operational lifespan, travel-times, and how few there are of them relative to the staggering number of stars and their systems.

Now, if their world was EM-silent, or just low-powered, you'd not detect the artificial EM signature of the civilization.
As Planet-4 has a frightening powerful ionosphere and magnetospehere and massive, high energy storms due to that...there's another couple of barriers to detecting any of planet-4's EM activity.

here's a shot of the Juggernaut exiting FTL...it looks like some kind of drop-out from a FtL type drive system...

I have read ADFs' book and how the teardrop/shard ship at the pole shielded the planet. Personally, I don't like the idea of a "planet-wide shield" which prevents taking of (but not landing LOL) or even render a whole planet invisible (why could they see it all of a sudden when they were hit by the neutrino explosion?) or make the atmosphere look inhabitable respectively*, so I'm glad they didn't put it in the movie. It just seems dull to me.

There's a much more plausible answer and I hope that RS goes for it (if a sequel is ever to be made):

1) The crew of the Covenant didn't know about Planet 4.

2) Weyland-Yutani is a shady, evil, ruthless Company.

3) What a coincidence, that Planet 4 is just on the way to Origae-6.

4) What an even bigger coincidence, that the "neutrino explosion" (why not just make it a Super Nova; Neutrinos are interacting with matter very veeeeeeery weakly *facepalm*) happens right before Planet 4s doorstep.

5) What a coincidence that of all cryo-pods it is the captains cryo-pod that malfunctions.

6) In the additional content we saw that David has made video messages, in which he explains the goo, the Engineers and so on. These video messages were addressed at WY.

7) At the end of AC mother addresses David, saying "Hello David" and "Yes David". Why is she cool with him being on board? There shouldn't be a David-unit on board?! Why is she accepting his security code (and don't tell me, that he has hacked Mother; you could assume that - being the board computer on a interstellar colonizing-mission - she has an invincible firewall)?

If you count 1-7, then the most fun explanation would be, that David has contacted WY from Planet 4 via encrypted radio transmission. He told them what he has found. WY then looked for Planet 4, found it and then deleted it from their star maps to make sure, nobody but them would find it. They then chose a star, that is in the direction of Planet 4 (Origae-6) and pretended, that they would send the Covenant there while giving Mother a secret order (Order 936 LOL) to halt close to Planet 4 (what a coincidence, that the ships' batteries were empty and they had to recharge them just close enough to receive Davids signal) and pick up David. That is why Mother accepted his security codes.

I know, I know... This story also has some plot-holes. For example why pretend to send a colonizing-mission and not just send a secret mission full of WY officers, androids and security personal to Planet 4? I. m. h. o. this whole "neutrino explosion" is just to stupid. There are only two ways that could work:

1) RS should have indicated that David was seeing the Covenant approach (via the Engineers' telescopes). He realized that they didn't seem to notice his signal as they weren't slowing down. So he then brought about the neutrino explosion (via the Engineers' miracle technology) in order to bring them to a halt and finally notice his signal.

2) Just leave the neutrino explosion out and have the Covenant receive Shaws/Davids signal. Mother then would wake them up and they would go investigate - just like in "Alien".

Either way - for it to be pure chance that the Covenant, on course to Origae-6, was hit by a neutrino explosion just short of Planet 4 - which coincidentally is right on the way to Origae-6 - just surpasses my suspension of disbelieve.

I am one hell of a Alien-fan but as much as it pains me I have to say that AC was one big mistake. He has written the Alien-franchise into a corner. You can destroy the mystery surrounding the Space Jockey, if you replace it with a new mystery: the Engineers - god-like beings, traveling through the universe for millions and billions of years, terraforming thousands and thousands of planets, creating and destroying life on them. It then is almost irrelevant weather they found the Alien or if they created it. But what you can't do is to destroy the mystery and the nimbus surrounding the Engineers... and then replace it with nothing but a malfunctioning, crazy robot AND THEN EVEN MAKE HIM THE CREATOR OF THE ALIEN.

*The most credible explanation would be, that the shield surrounding the planet would distort the spectral band from seen at a distance, as to make the atmosphere look inhabitable in a spectographic analysis. This way they could have seen the planet but would have dismissed it as a candidate because of unsuitable atmosphere. But this explanation would be to difficult for a lay-audience from the US I guess.

Jdvyne:

There is the most fun explanation and you have the most logical. In sci-fi the most logical seems to be the way to go. When you go for the most fun option then it could fit into fantasy but not sci-fi which is supposed to be somewhat rooted in a plausible reality.

I agree that AC wasn't a very good movie, I wish that hey could have gone for something else although the idea of exploring other worlds isn't bad in itself. There were very few characters to care about also add to that the crappiness to make David the creator of the Xeno.

We have a problem that AC got made but they could maybe fix it, not sure how though. They should try to fix the Engineers and make them more interesting and mysterious and make some sort of difference between them and the SJ. I would find it alright if they make sure that David only created his own version of it and therefore not being that relevant to that part of the story.

David was better in Prometheus, they made his story worse in this movie. Making him the creator of the Xeno was one thing and to make the second part almost only about him was really bad.

“But this explanation would be to difficult for a lay-audience from the US I guess.”

Probably from anywhere as long as you don’t know much about how that works. I’m not sure if I would be able to totally understand it.