If you're searching for samples in Helldivers 2, you're likely looking to upgrade your ship modules, buffing the power of the many stratagems you can bring to bear on the battlefield. Unlike the medals that you use to unlock new guns in your Warbonds, samples come in three different varieties that you can only collect in certain missions.

If you haven't been playing the game long, you're likely just grabbing anything you find, but when it comes to the final ship module in each section, you'll need to locate some extremely rare samples if you want to unlock them. Here's how to find all three sample types in Helldivers 2, where they most commonly appear, and how to locate those elusive super samples to finish off your upgrades.

Helldivers 2 sample types and what they do

There are three different types of sample that you can collect in Helldivers 2, but they only spawn in certain difficulties:

• Common samples: These are available in all nine difficulties.
• Rare samples: These are only available in difficulties four to nine; Challenging, Hard, Extreme, Suicide Mission, Impossible, and Helldive.
• Super samples: These are only available in difficulties seven to nine; Suicide Mission, Impossible, and Helldive.

To increase your available difficulties, you need to complete a full operation of the previous difficulty—for example, to access Suicide Mission's super samples you need to finish an Extreme operation first. While common and rare types will let you upgrade the first two ship modules in each section, you'll need all three types, including super samples, to unlock the last. 

The most important thing to remember; don't forget to pick up your sample case if you die—it's marked with a little test tube symbol and you can also see it on the map. Since samples are shared, you also don't have to worry about other players pilfering them. 

How to get common samples

This type is the easiest to find since they're pretty much everywhere. You can recognise them by their split-circle symbol, and they're generally found at:

• Objectives
• Sub-objectives
• Extraction points
• Terminind nests or Automaton fabricators marked in red on the map
• Points of interest

They really are everywhere. Your best bet if you want to farm them is to pick a big open-world mission and explore as many points of interest as you can. If your map has a radar station sub-objective, completing that will reveal all points of interest, letting you run around and swipe samples to your heart's content.

How to get rare samples

Since rare samples only appear on difficulties four to nine, you'll need to be playing on at least Challenging to get them. These are marked by a square symbol with the bottom-left corner cut away, and the best way to find them is via points of interest. Though they can spawn in a variety of locations, it seems incredibly hit-or-miss whether they'll turn up near an objective or in an enemy base. It's worth keeping an eye out, but if you're specifically looking to farm these, then points of interest should be your go-to method.

How to get super samples

The final sample type only appears on difficulties seven to nine, so you'll have to be playing on Suicide Mission or above for a chance to get them. Super samples—or super uranium, as it's also called—are hard to find, and you can only gather them at a specific location on each map. This excludes the maps from the Eradicate Terminid Swarm, Eradicate Automaton Forces, and Retrieve Essential Personnel missions. 

You'll want to look for a fist-shaped standing rock with silvery lines as pictured above, since super samples spawn around its base. These floating silver balls are marked with a four square symbol and are easy to spot. I've found the best way to locate the super sample rock is to view your map and look for a little grey ball surrounded by a silvery outline, also pictured above.

Since points of interest appear when you hover over them, even if you haven't discovered them yet—and the super sample rock is a point of interest—you can confirm whether it's likely to be the right place when you move the cursor over it. Of course, you can always activate a radar station if there's one on your map to reveal all points of interest as well.

It's worth choosing a world with clear visibility so you can spot the rock. Be sure to avoid jungles, sand planets, visibility related modifiers, and do your mission in the daytime by choosing the light side of the planet. You don't need all that many super samples for your Ship Modules, but if you're looking to get lots, blitz missions are the best farming method due to their short duration, smaller map, and quick-to-complete objectives.