<p><a href="https://mars.nasa.gov/mars-exploration/missions/mariner-8-9/" rel="nofollow noreferrer">NASA says about the Mariner 9</a>:</p>
<blockquote>
<p>The spacecraft also provided the first closeup pictures of the two small, irregular Martian moons: Phobos and Deimos.</p>
</blockquote>
<p>This must have happened somewhere between November 14th, 1971 and October 27th, 1972. <a href="https://www.planetary.org/space-images/deimos-from-mariner-9" rel="nofollow noreferrer">Here</a> is a picture from January 27th, 1972 which shows them:</p>
<p><a href="https://i.sstatic.net/TsRmH.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/TsRmH.jpg" alt="enter image description here" /></a></p>
<p>FWIW, the only other spacecraft to reach Mars between then and 1973 was the Russian <a href="https://en.wikipedia.org/wiki/Mars_2" rel="nofollow noreferrer">Mars 2</a>.</p>

CC BY-SA 4.0
2022-05-17T14:45:15.907Z
2022-05-17T14:45:15.907Z
Glorfindel
<p><a href="https://en.wikipedia.org/wiki/Deimos_(moon)" rel="nofollow noreferrer">Deimos</a> -- Mars' smallest moon -- has only two named features: the Swift crater and the Voltaire crater. Based on the <a href="https://planetarynames.wr.usgs.gov/Feature/5789" rel="nofollow noreferrer">Gazetteer of Planetary Nomenclature</a>, their names were approved in 1973.</p>
<p>Given the size of these craters, I assume they weren't discovered until the space age. Perhaps during a Mariner flyby? When were these craters first discovered?</p>

<mars><crater><deimos>
When were Swift and Voltaire discovered?
usernumber
# When were Swift and Voltaire discovered?

(Asked by: username_0 on 2022-05-17)

[Deimos](https://en.wikipedia.org/wiki/Deimos_(moon)) -- Mars' smallest moon -- has only two named features: the Swift crater and the Voltaire crater. Based on the [Gazetteer of Planetary Nomenclature](https://planetarynames.wr.usgs.gov/Feature/5789), their names were approved in 1973.

Given the size of these craters, I assume they weren't discovered until the space age. Perhaps during a Mariner flyby? When were these craters first discovered?

**Tags:** mars, crater, deimos

---

## 1 answers

### Answer by username_1 on 2022-05-17. Score: 3

[NASA says about the Mariner 9](https://mars.nasa.gov/mars-exploration/missions/mariner-8-9/):

> The spacecraft also provided the first closeup pictures of the two small, irregular Martian moons: Phobos and Deimos.

This must have happened somewhere between November 14th, 1971 and October 27th, 1972. [Here](https://www.planetary.org/space-images/deimos-from-mariner-9) is a picture from January 27th, 1972 which shows them:

[![enter image description here](https://i.sstatic.net/TsRmH.jpg)](https://i.sstatic.net/TsRmH.jpg)

FWIW, the only other spacecraft to reach Mars between then and 1973 was the Russian [Mars 2](https://en.wikipedia.org/wiki/Mars_2).


---

