<p>My best guess (though I don't know about every mission) is that we have at least seeded our moon with life when we visited it.  We have also likely seeded Venus, Mars, and Jupiter with the various probes we have sent to each.  As far as I know, we have only done flybys or put probes in orbit for the other planets and moons, so they have likely not been seeded yet.  I would like clarification / confirmation, and other possible locations.  I know we now generally sterilize our probes, but the procedure could be incomplete, and I don't believe we have always sterilized them in the past.</p>

CC BY-SA 3.0
2016-03-02T21:30:58.410Z
"sterilize" is not a single thing.  Depending on the level of risk that contamination would have, craft would be cleaned to a greater or lesser degree.
BowlOfRed
CC BY-SA 3.0
2016-03-02T22:13:19.320Z
You may be able to refine your answer by studying NASA's planetary protection website: http://planetaryprotection.nasa.gov/missions
Gerald
CC BY-SA 3.0
2016-03-02T17:44:06.290Z
2016-03-02T17:44:06.290Z
Jonathan
<p>This would seem to be constrained to planets and moons earth has landed on or impacted at all, as we have no way of telling after the fact whether a lander was perfectly sterilized. That list is as follows:</p>

<p><strong>Planets:</strong></p>

<ul>
<li><p><em>Mercury</em>: <a href="https://en.wikipedia.org/wiki/MESSENGER" rel="nofollow">USA's MESSENGER</a> in 2015 de-orbited and crashed upon completion of mission. Contamination is unlikely because of high impact and temperatures.</p></li>
<li><p><em>Venus</em>: <a href="https://en.wikipedia.org/wiki/Venera" rel="nofollow">13 missions by the USSR</a> and <a href="https://en.wikipedia.org/wiki/Pioneer_Venus_Multiprobe" rel="nofollow">1 by the USA</a> (1966-1985). Contamination unlikely due to harsh environment.</p></li>
<li><p><em>Mars</em>: 12 missions, multi-national origins. Contamination plausible.</p></li>
<li><p><em>Jupiter</em>: <a href="https://en.wikipedia.org/wiki/Galileo_(spacecraft)#Spacecraft" rel="nofollow">The Galileo missions</a> (2), by the USA Contamination unlikely, because of pressure.</p></li>
</ul>

<p><strong>Moons:</strong></p>

<ul>
<li><p><em>Earth's moon</em>: Far too many to count, myriad landings. Contamination plausible.</p></li>
<li><p><em>Saturn's moon Titan</em>: <a href="https://en.wikipedia.org/wiki/Huygens_(spacecraft)" rel="nofollow">Huygens probe</a>, landed by the ESA (2005) Contamination Plausible.</p></li>
</ul>

<p><strong>Asteroids/Comets:</strong></p>

<ul>
<li><p><em>Eros</em>: <a href="https://en.wikipedia.org/wiki/NEAR_Shoemaker" rel="nofollow">2001 landing by USA</a>. Contamination possible.</p></li>
<li><p><em>Itokawa</em>: <a href="https://en.wikipedia.org/wiki/Hayabusa" rel="nofollow">2005 landing by Japan</a>. Contamination possible.</p></li>
<li><p><em>Comet 9P/Tempel 1</em>: <a href="https://en.wikipedia.org/wiki/Deep_Impact_(spacecraft)" rel="nofollow">2005 landing by USA</a>. Contamination is unlikely because of high impact speeds.</p></li>
<li><p><em>Comet 67P/Churyumov–Gerasimenko</em>: <a href="https://en.wikipedia.org/wiki/Rosetta_(spacecraft)" rel="nofollow">2014 landing by ESA</a>. Contamination possible.</p></li>
</ul>

CC BY-SA 3.0
2016-03-03T05:31:02.560Z
2016-03-03T14:01:31.767Z
2016-03-03T14:01:31.767Z
Pulchritude
<p>Which planets and moons have we accidentally (or purposely) seeded with life?  I would expect this to be any planet or moon we have sent an unsterilized (or not fully sterilized) lander to, or crashed anything into.  </p>

<p>I am speaking largely of bacteria and other microorganisms that might have hitched a ride on our spacecraft, or any life that was deliberately taken to and left on another world (which I am not aware).  I know we went to the moon, we at the very least "seeded the moon" temporarily with life (humans) and probably bacteria on the space suits / lander / equipment we sent.</p>

<p>I wondering where we have "seeded" / brought life (even if it doesn't / didn't survive there).</p>

CC BY-SA 3.0
2016-03-02T19:02:31.240Z
The question would seem to imply that "seeding" is sufficient, even if the body in question contains no medium in which any terrestrial life could possibly grow. Or am I missing something?
Donald.McLean
CC BY-SA 3.0
2016-03-02T19:40:05.743Z
Yes, that is what I am asking about, where we have actually sent life (not whether or not it will actually grow there).
Jonathan
CC BY-SA 3.0
2016-03-02T20:13:37.683Z
As I understand it, it's very difficult to completely sterilize (as in, kill every last microbe), on a spacecraft, though NASA and most nations that launch space craft have made an effort to address this concern.    https://en.wikipedia.org/wiki/Planetary_protection
userLTK
CC BY-SA 3.0
2016-03-03T11:19:14.387Z
Space craft are not the only possible vectors for biological contamination of other bodies within the Solar System. For some idea of transfer of surface material between terrestrial planets see [this abstract](http://adsabs.harvard.edu/abs/1993Metic..28Q.398M)
Conrad Turner
<planet><earth><life><natural-satellites><origin-of-life>
What planets and moons have we seeded with life (if any)?
Jonathan
# What planets and moons have we seeded with life (if any)?

(Asked by: username_0 on 2016-03-02)

Which planets and moons have we accidentally (or purposely) seeded with life? I would expect this to be any planet or moon we have sent an unsterilized (or not fully sterilized) lander to, or crashed anything into.

I am speaking largely of bacteria and other microorganisms that might have hitched a ride on our spacecraft, or any life that was deliberately taken to and left on another world (which I am not aware). I know we went to the moon, we at the very least "seeded the moon" temporarily with life (humans) and probably bacteria on the space suits / lander / equipment we sent.

I wondering where we have "seeded" / brought life (even if it doesn't / didn't survive there).

**Tags:** planet, earth, life, natural-satellites, origin-of-life

> **Comments:**
> **username_1**: The question would seem to imply that "seeding" is sufficient, even if the body in question contains no medium in which any terrestrial life could possibly grow. Or am I missing something?  
> **username_0**: Yes, that is what I am asking about, where we have actually sent life (not whether or not it will actually grow there).  
> **username_2**: As I understand it, it's very difficult to completely sterilize (as in, kill every last microbe), on a spacecraft, though NASA and most nations that launch space craft have made an effort to address this concern.    https://en.wikipedia.org/wiki/Planetary_protection  
> **username_3**: Space craft are not the only possible vectors for biological contamination of other bodies within the Solar System. For some idea of transfer of surface material between terrestrial planets see [this abstract](http://adsabs.harvard.edu/abs/1993Metic..28Q.398M)  

---

## 2 answers

### Answer by username_6 on 2016-03-03. Score: 5 | Accepted answer

This would seem to be constrained to planets and moons earth has landed on or impacted at all, as we have no way of telling after the fact whether a lander was perfectly sterilized. That list is as follows:

**Planets:**

* *Mercury*: [USA's MESSENGER](https://en.wikipedia.org/wiki/MESSENGER) in 2015 de-orbited and crashed upon completion of mission. Contamination is unlikely because of high impact and temperatures.
* *Venus*: [13 missions by the USSR](https://en.wikipedia.org/wiki/Venera) and [1 by the USA](https://en.wikipedia.org/wiki/Pioneer_Venus_Multiprobe) (1966-1985). Contamination unlikely due to harsh environment.
* *Mars*: 12 missions, multi-national origins. Contamination plausible.
* *Jupiter*: [The Galileo missions](https://en.wikipedia.org/wiki/Galileo_(spacecraft)#Spacecraft) (2), by the USA Contamination unlikely, because of pressure.

**Moons:**

* *Earth's moon*: Far too many to count, myriad landings. Contamination plausible.
* *Saturn's moon Titan*: [Huygens probe](https://en.wikipedia.org/wiki/Huygens_(spacecraft)), landed by the ESA (2005) Contamination Plausible.

**Asteroids/Comets:**

* *Eros*: [2001 landing by USA](https://en.wikipedia.org/wiki/NEAR_Shoemaker). Contamination possible.
* *Itokawa*: [2005 landing by Japan](https://en.wikipedia.org/wiki/Hayabusa). Contamination possible.
* *Comet 9P/Tempel 1*: [2005 landing by USA](https://en.wikipedia.org/wiki/Deep_Impact_(spacecraft)). Contamination is unlikely because of high impact speeds.
* *Comet 67P/Churyumov–Gerasimenko*: [2014 landing by ESA](https://en.wikipedia.org/wiki/Rosetta_(spacecraft)). Contamination possible.


---

### Answer by username_0 on 2016-03-02. Score: 1

My best guess (though I don't know about every mission) is that we have at least seeded our moon with life when we visited it. We have also likely seeded Venus, Mars, and Jupiter with the various probes we have sent to each. As far as I know, we have only done flybys or put probes in orbit for the other planets and moons, so they have likely not been seeded yet. I would like clarification / confirmation, and other possible locations. I know we now generally sterilize our probes, but the procedure could be incomplete, and I don't believe we have always sterilized them in the past.

> **Comments:**
> **username_4**: "sterilize" is not a single thing.  Depending on the level of risk that contamination would have, craft would be cleaned to a greater or lesser degree.  
> **username_5**: You may be able to refine your answer by studying NASA's planetary protection website: http://planetaryprotection.nasa.gov/missions  

---

