<p>The answer can be deduced from the <a href="https://landsat.gsfc.nasa.gov/landsat-8/tirs-design" rel="nofollow noreferrer">main landsat 8 page</a>, where you find the following picture of  QWIP detector arrays, and QWIP is short for <em>Quantum well infrared photodetector</em>, I added a gray arrow pointing to one of the 3 arrays.</p>
<p><a href="https://i.sstatic.net/tHBt8.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/tHBt8.png" alt="QWIP detector array" /></a></p>
<p>I cannot give you the exact dimensions in mm, but it is clear from the SMD chip elements (SMD = surface mounted device) - one of them I highlighted with a gray ellipse, that each sensor is probably coin-sized, if not smaller. Or in numbers: I <em>guess</em> a side length <span class="math-container">$1.5\pm1 {\rm cm}$</span> seems reasonable, it depends a bit whether the sensor has the same size as the silver square or whether there is a border around.</p>
<h3>References</h3>
<ul>
<li><a href="https://eepower.com/resistor-guide/resistor-standards-and-codes/resistor-smd-code/" rel="nofollow noreferrer">Some introduction to SMD resistors</a></li>
</ul>

CC BY-SA 4.0
2021-03-21T11:56:55.200Z
The circled object looks more like a diode in a [MELF](https://en.wikipedia.org/wiki/Metal_electrode_leadless_face) package to my eye.  Same ballpark size though (~2×4 mm).
Alex Hajnal
CC BY-SA 4.0
2021-03-21T12:07:09.753Z
@AlexHajnal Could well be. If all you have is a hammer, everything looks like a nail :-)
B--rian
CC BY-SA 4.0
2021-03-21T12:10:55.633Z
Does anybody have background info on the screws used? In my experimental years, a screw was almost certainly a [M5](https://en.wikipedia.org/wiki/ISO_metric_screw_thread), but is that true here as well?
B--rian
CC BY-SA 4.0
2021-03-21T13:46:57.267Z
Screws on such devices are in my experience always chosen for the required load - and physical dimensions whatever is practical and for how small you can get without compromising stability. Could be anything between M2 and M6.
planetmaker
CC BY-SA 4.0
2021-03-21T14:48:33.967Z
it links to the paywalled [The next Landsat satellite: The Landsat Data Continuity Mission](https://www.sciencedirect.com/science/article/abs/pii/S0034425712000363) but even the abstract might be helpful: "two thermal bands with a 100 m resolution" If the focal length of the imaging optics is known, the pixel size can then be estimated. **update:** Here you go! https://core.ac.uk/download/pdf/188079092.pdf
uhoh
CC BY-SA 4.0
2021-03-19T12:16:42.773Z
2021-03-21T12:16:22.740Z
2021-03-21T12:16:22.740Z
B--rian
<p>According to the suggested tags, this must be the right forum:</p>
<p>I <a href="https://landsat.gsfc.nasa.gov/landsat-8/operational-land-imager" rel="nofollow noreferrer">found</a>  that for each band of Landsat 8 over 7000 detectors are on the array. Does anyone know how big each of the sensors is?</p>

CC BY-SA 4.0
2021-03-19T11:57:59.050Z
The official landsat website has many details on the instruments: https://landsat.gsfc.nasa.gov/landsat-8/landsat-8-overview
B--rian
CC BY-SA 4.0
2021-03-21T16:36:23.133Z
This is the wrong forum.  Landsat is an Earth observation satellite. It doesn't do astronomy.  The Space Exploration stack exchange is the right forum (but this old question is too old to worry about closing)
James K
<satellite>
What is the detector size of LANDSAT 8's detector array?
geoworks
# What is the detector size of LANDSAT 8's detector array?

(Asked by: username_0 on 2015-09-14)

According to the suggested tags, this must be the right forum:

I [found](https://landsat.gsfc.nasa.gov/landsat-8/operational-land-imager) that for each band of Landsat 8 over 7000 detectors are on the array. Does anyone know how big each of the sensors is?

**Tags:** satellite
> **Comments:**
> **username_1**: The official landsat website has many details on the instruments: https://landsat.gsfc.nasa.gov/landsat-8/landsat-8-overview  
> **username_2**: This is the wrong forum.  Landsat is an Earth observation satellite. It doesn't do astronomy.  The Space Exploration stack exchange is the right forum (but this old question is too old to worry about closing)  

---

## 1 answers

### Answer by username_1 on 2021-03-19. Score: 1

The answer can be deduced from the [main landsat 8 page](https://landsat.gsfc.nasa.gov/landsat-8/tirs-design), where you find the following picture of QWIP detector arrays, and QWIP is short for *Quantum well infrared photodetector*, I added a gray arrow pointing to one of the 3 arrays.

[![QWIP detector array](https://i.sstatic.net/tHBt8.png)](https://i.sstatic.net/tHBt8.png)

I cannot give you the exact dimensions in mm, but it is clear from the SMD chip elements (SMD = surface mounted device) - one of them I highlighted with a gray ellipse, that each sensor is probably coin-sized, if not smaller. Or in numbers: I *guess* a side length $1.5\pm1 {\rm cm}$ seems reasonable, it depends a bit whether the sensor has the same size as the silver square or whether there is a border around.

### References

* [Some introduction to SMD resistors](https://eepower.com/resistor-guide/resistor-standards-and-codes/resistor-smd-code/)

> **Comments:**
> **username_3**: The circled object looks more like a diode in a [MELF](https://en.wikipedia.org/wiki/Metal_electrode_leadless_face) package to my eye.  Same ballpark size though (~2×4 mm).  
> **username_1**: @AlexHajnal Could well be. If all you have is a hammer, everything looks like a nail :-)  
> **username_1**: Does anybody have background info on the screws used? In my experimental years, a screw was almost certainly a [M5](https://en.wikipedia.org/wiki/ISO_metric_screw_thread), but is that true here as well?  
> **username_4**: Screws on such devices are in my experience always chosen for the required load - and physical dimensions whatever is practical and for how small you can get without compromising stability. Could be anything between M2 and M6.  
> **username_5**: it links to the paywalled [The next Landsat satellite: The Landsat Data Continuity Mission](https://www.sciencedirect.com/science/article/abs/pii/S0034425712000363) but even the abstract might be helpful: "two thermal bands with a 100 m resolution" If the focal length of the imaging optics is known, the pixel size can then be estimated. **update:** Here you go! https://core.ac.uk/download/pdf/188079092.pdf  

---

