<p>Yes. <a href="https://en.wikipedia.org/wiki/Trojan_(celestial_body)" rel="nofollow noreferrer">Trojan orbits</a> (60° before or after the Moon) are even stable in most cases. These points are called the L₄ and L₅ points, which are two of the five <a href="https://en.wikipedia.org/wiki/Lagrangian_point" rel="nofollow noreferrer">Lagrangian points</a>.</p>
<p>These orbits are mostly impractical (nothing is there).</p>
<p>Today the best known is the Chinese Queqiao satellite, which is a communication relay to their probe on the far side of the Moon. Instead of using L₄ or L₅, Queqiao is in a <a href="https://en.wikipedia.org/wiki/Halo_orbit" rel="nofollow noreferrer">halo orbit</a> around another Lagrangian point; Earth-Moon L₂.</p>

CC BY-SA 4.0
2019-07-20T23:20:00.623Z
2024-10-10T08:31:29.010Z
2024-10-10T08:31:29.010Z
peterh
<blockquote>
  <p>Has this ever been done in practice?</p>
</blockquote>

<p>Not intentionally, and not by humankind. But by nature, the answer is yes. Thousands of objects are known to co-orbit with Jupiter about the Sun-Jupiter L4 and L5 points, millions are thought to exist. <a href="https://en.wikipedia.org/wiki/Trojan_(celestial_body)" rel="noreferrer">Trojans</a> (the generic name for small objects that co-orbit with a somewhat large object about an even larger object, with the small objects in pseudo orbits about the triangular Lagrange points) are known to exist for Neptune, Mars, Uranus, and Earth. Two of Saturn's moons, Tethys and Dione, have trojans in pseudo orbits about their triangular Lagrange points.</p>

CC BY-SA 4.0
2019-07-21T12:29:45.097Z
...but not for the Moon though?
uhoh
CC BY-SA 4.0
2019-07-21T13:53:39.587Z
@uhoh See https://en.wikipedia.org/wiki/Kordylewski_cloud
PM 2Ring
CC BY-SA 4.0
2019-07-21T16:06:26.920Z
@PM2Ring Oh, now that you mention it, I remember reading about the confirmation last year.  there was a patch of zodiacal light with a difference in polarization which stayed in the right place. [Part I (modeling)](https://academic.oup.com/mnras/article/482/3/3966/5203586), [Part II (observation)](https://academic.oup.com/mnras/article/482/1/762/5114270). I'd added those [here](https://space.stackexchange.com/q/31865/12102) last year, then forgot. Thanks!
uhoh
CC BY-SA 4.0
2019-07-21T12:05:04.003Z
2019-07-21T12:05:04.003Z
David Hammen
<p>One limitation of using L4 or L5 is, ironically, their natural stability. They are now known to attract <a href="https://en.wikipedia.org/wiki/Kordylewski_cloud" rel="nofollow noreferrer">dust clouds</a>. Putting and station-keeping a satellite at the ostensibly unstable Lagrange points avoids having to deal with a higher dust density. In addition, L1 and L2 offers a closer view of the Moon.</p>

CC BY-SA 4.0
2023-09-04T19:55:09.980Z
2024-09-28T22:26:01.653Z
2024-09-28T22:26:01.653Z
Oscar Lanzi
<p>Would it be possible to put a satellite into the same orbit as the Moon, but far enough ahead or behind the Moon to remain in place?</p>

<p>Has this ever been done in practice?</p>

CC BY-SA 4.0
2019-07-20T22:23:27.770Z
It looks like it's already been done: https://en.wikipedia.org/wiki/List_of_objects_at_Lagrangian_points#L4_and_L5 Or at least, it's planned to put satellutes in the Earth-Moon L4 & L5 points.
PM 2Ring
CC BY-SA 4.0
2019-07-20T22:53:05.813Z
This is a really interesting question, but I'm voting to close this question as off-topic because it's about a potential artificial satellite mission itself, and not about Astronomy. See [What types of questions should I avoid asking?](https://astronomy.stackexchange.com/help/dont-ask) and also  [What topics can I ask about here?](https://astronomy.stackexchange.com/help/on-topic) However it's a great question for [Space SE](https://space.stackexchange.com/)!
uhoh
CC BY-SA 4.0
2019-07-21T11:55:20.187Z
I will vote to reopen if this question is closed. This question is on-topic, particularly when generalized beyond the Earth-Moon system.
David Hammen
CC BY-SA 4.0
2019-07-21T18:11:22.097Z
The reason I asked this question is because it would be a way of establishing communication on the far side of the moon. I don't want to consider the Lagrange points, I was wondering if a satellite could follow the same orbit as the moon. It would have to be far enough ahead or behind to be unaffected by the moon. Would it still be in sight of the moon (i.e non the less close enough). Could an object follow the moon's orbit?
Bingohank
CC BY-SA 4.0
2024-09-29T18:04:44.350Z
@Bingohank How would your proposed satellites help with communication to (or on) the far side of the Moon?
PM 2Ring
<the-moon>
Satellite in orbit in front of and behind the Moon
Bingohank
# Satellite in orbit in front of and behind the Moon

(Asked by: username_0 on 2019-07-20)

Would it be possible to put a satellite into the same orbit as the Moon, but far enough ahead or behind the Moon to remain in place?

Has this ever been done in practice?

**Tags:** the-moon

> **Comments:**
> **username_1**: It looks like it's already been done: https://en.wikipedia.org/wiki/List_of_objects_at_Lagrangian_points#L4_and_L5 Or at least, it's planned to put satellutes in the Earth-Moon L4 & L5 points.  
> **username_2**: This is a really interesting question, but I'm voting to close this question as off-topic because it's about a potential artificial satellite mission itself, and not about Astronomy. See [What types of questions should I avoid asking?](https://astronomy.stackexchange.com/help/dont-ask) and also  [What topics can I ask about here?](https://astronomy.stackexchange.com/help/on-topic) However it's a great question for [Space SE](https://space.stackexchange.com/)!  
> **username_3**: I will vote to reopen if this question is closed. This question is on-topic, particularly when generalized beyond the Earth-Moon system.  
> **username_0**: The reason I asked this question is because it would be a way of establishing communication on the far side of the moon. I don't want to consider the Lagrange points, I was wondering if a satellite could follow the same orbit as the moon. It would have to be far enough ahead or behind to be unaffected by the moon. Would it still be in sight of the moon (i.e non the less close enough). Could an object follow the moon's orbit?  
> **username_1**: @username_0 How would your proposed satellites help with communication to (or on) the far side of the Moon?  

---

## 3 answers

### Answer by username_5 on 2023-09-04. Score: 4 | Accepted answer

One limitation of using L4 or L5 is, ironically, their natural stability. They are now known to attract [dust clouds](https://en.wikipedia.org/wiki/Kordylewski_cloud). Putting and station-keeping a satellite at the ostensibly unstable Lagrange points avoids having to deal with a higher dust density. In addition, L1 and L2 offers a closer view of the Moon.


---

### Answer by username_4 on 2019-07-20. Score: 13

Yes. [Trojan orbits](https://en.wikipedia.org/wiki/Trojan_(celestial_body)) (60° before or after the Moon) are even stable in most cases. These points are called the L₄ and L₅ points, which are two of the five [Lagrangian points](https://en.wikipedia.org/wiki/Lagrangian_point).

These orbits are mostly impractical (nothing is there).

Today the best known is the Chinese Queqiao satellite, which is a communication relay to their probe on the far side of the Moon. Instead of using L₄ or L₅, Queqiao is in a [halo orbit](https://en.wikipedia.org/wiki/Halo_orbit) around another Lagrangian point; Earth-Moon L₂.


---

### Answer by username_3 on 2019-07-21. Score: 6

> Has this ever been done in practice?

Not intentionally, and not by humankind. But by nature, the answer is yes. Thousands of objects are known to co-orbit with Jupiter about the Sun-Jupiter L4 and L5 points, millions are thought to exist. [Trojans](https://en.wikipedia.org/wiki/Trojan_(celestial_body)) (the generic name for small objects that co-orbit with a somewhat large object about an even larger object, with the small objects in pseudo orbits about the triangular Lagrange points) are known to exist for Neptune, Mars, Uranus, and Earth. Two of Saturn's moons, Tethys and Dione, have trojans in pseudo orbits about their triangular Lagrange points.

> **Comments:**
> **username_2**: ...but not for the Moon though?  
> **username_1**: @username_2 See https://en.wikipedia.org/wiki/Kordylewski_cloud  
> **username_2**: @PM2Ring Oh, now that you mention it, I remember reading about the confirmation last year.  there was a patch of zodiacal light with a difference in polarization which stayed in the right place. [Part I (modeling)](https://academic.oup.com/mnras/article/482/3/3966/5203586), [Part II (observation)](https://academic.oup.com/mnras/article/482/1/762/5114270). I'd added those [here](https://space.stackexchange.com/q/31865/12102) last year, then forgot. Thanks!  

---

