Post Reply 
 
Thread Rating:
  • 1 Vote(s) - 5 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Our dear payload, Mr Moss. It's needs and it's limits.
Author Message
MBobrik Offline
Member
***

Posts: 203
Joined: Dec 2014
Post: #1
Question Our dear payload, Mr Moss. It's needs and it's limits.
From KSP forum.


Bunsen Wrote:Forgive me if this was also discussed, but I don't see "tiny encapsulated atmosphere" being compatible with "growing in the dark." If it grows in the dark, it must get its energy from metabolizing something, and that usually requires either taking oxygen, getting rid of carbon dioxide or something, or both. If you want an organism to grow for long in a small, closed atmosphere, you have to provide some continued energy input. Otherwise, there's going to be a pretty tight limit on how much interesting stuff can happen before the chemistry hits a wall.

This was AFAIK never brought up before. And I would thus like to open a more general discussion about what conditions, chemical, physical, etc... our moss exactly needs, and what are the limits of its tolerance we should not exceed.
12-19-2014 01:53 AM
Find all posts by this user Quote this message in a reply
Mazon Del Offline
Junior Member
**

Posts: 26
Joined: Dec 2014
Post: #2
RE: Our dear payload, Mr Moss. It's needs and it's limits.
The moss is capable of metabolizing sucrose in the absence of light. I believe he even stated that in such an environment, the moss will actually produce CO2 instead of the standard O2. The biologist I have been discussing this with (Luis Vidali from WPI) tells me that it would be ideal to grow the moss in the absence of light because the gravitometric response (how effected the moss is by gravity) of the moss is increased in dark environments. The working theory being that the moss is attempting to grow towards where it thinks light must be.

As far as what we are measuring, we are looking at two things.

First at foremost, at the two main gravity levels we are looking into (roughly 0.1G AKA: The moon. And roughly 0.3G AKA Mars), is there enough gravity for the moss to detect what is up vs down. This is useful data that currently is unknown and could be very helpful towards creating space based garden infrastructure. If plants cannot grow correctly in zero G (many have issues) but they can grow correctly in 0.1G, this could allow for a gardening section that operates in a centrifuge or similar system. The stresses imparted by a 0.1G rotation are much easier to engineer for than a full 1G.

Secondly, how well does the moss grow in this environment vs an Earth based environment. This can provide additional information used to help eventual spaced based gardening techniques. Unlikely, but it could be quite possible that plants grow far better in Mars gravity than Earth gravity (just enough gravity to help them do their thing, but not enough that the plants bother devoting as much energy towards an internal structure). Nobody knows, so we will see!

Edit: Incidentally! Wooo! First reply post on the forums!
(This post was last modified: 12-19-2014 03:30 AM by Mazon Del.)
12-19-2014 03:29 AM
Find all posts by this user Quote this message in a reply
Newt Offline
Flying Buttress
***

Posts: 134
Joined: Dec 2014
Post: #3
RE: Our dear payload, Mr Moss. It's needs and it's limits.
Do we have a clear idea of mission duration? It depends greatly on our orbit's specifics, I suppose, and we only have a logical guess about those at the moment, so we probably can only make a logical guess about maximum duration, and thus about how much air/water et cetera we need to pack if we want the longest possible mission. If the moss lives without inputs of air/water it would probably simplify design quite a bit, but possibly make the mission limited by how long the moss can survive before it suffocates, which is not really what I thought we were looking for.
12-19-2014 03:31 AM
Find all posts by this user Quote this message in a reply
deljr15 Offline
Administrator
*******

Posts: 102
Joined: Dec 2014
Reputation: 0
Post: #4
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 03:31 AM)Newt Wrote:  If the moss lives without inputs of air/water it would probably simplify design quite a bit, but possibly make the mission limited by how long the moss can survive before it suffocates, which is not really what I thought we were looking for.

Well I have been under the impression that is exactly what we are going for. A life support system that is totally passive.

But this brings up a good topic. How long does it need to survive for. Not just mission flight duration but any time waiting on the ground for launch. We will need to know how long it will take from sealing the moss to launch.
12-19-2014 04:18 AM
Find all posts by this user Quote this message in a reply
sndrtj Offline
Junior Member
**

Posts: 4
Joined: Dec 2014
Post: #5
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 03:29 AM)Mazon Del Wrote:  The moss is capable of metabolizing sucrose in the absence of light. I believe he even stated that in such an environment, the moss will actually produce CO2 instead of the standard O2. The biologist I have been discussing this with (Luis Vidali from WPI) tells me that it would be ideal to grow the moss in the absence of light because the gravitometric response (how effected the moss is by gravity) of the moss is increased in dark environments. The working theory being that the moss is attempting to grow towards where it thinks light must be.

As far as what we are measuring, we are looking at two things.

First at foremost, at the two main gravity levels we are looking into (roughly 0.1G AKA: The moon. And roughly 0.3G AKA Mars), is there enough gravity for the moss to detect what is up vs down. This is useful data that currently is unknown and could be very helpful towards creating space based garden infrastructure. If plants cannot grow correctly in zero G (many have issues) but they can grow correctly in 0.1G, this could allow for a gardening section that operates in a centrifuge or similar system. The stresses imparted by a 0.1G rotation are much easier to engineer for than a full 1G.

Secondly, how well does the moss grow in this environment vs an Earth based environment. This can provide additional information used to help eventual spaced based gardening techniques. Unlikely, but it could be quite possible that plants grow far better in Mars gravity than Earth gravity (just enough gravity to help them do their thing, but not enough that the plants bother devoting as much energy towards an internal structure). Nobody knows, so we will see!

Edit: Incidentally! Wooo! First reply post on the forums!

It is going to need some energy source. If it can metabolize sucrose (or some other sugar) in agar, that makes the lighting problem mostly irrelevant. However, of course, photosynthesis is a moss' natural energy source. Could you ask mr Vidali for some references on moss growth in the absence of light?

If there's no light, you're right that it will not produce O2, and only CO2. Plants usually get their energy source from photosynthesis, which is:
CO2 + Light = Glucose (= sugar) + O2.
It then burns the glucose in oxidative phosphorylation:
glucose + O2 = CO2 + ~35 ATP. The ATP is the real biological energy unit.
So in a closed system, plants can be completely cyclical. Our oxygen is only there because plants make more glucose (and hence oxygen) than they use ;-).

So, without light, it might have glucose, but eventually it's going to out of oxygen. One can still produce 2 ATP molecules per glucose molecule through glycolysis, but that's nothing compared to the energy extracted by oxidative processes.

So eventually it'll die, whereas a system including light could theoretically stay alive forever.

How soon it will die is something I don't know. That is easy to test however. If we can attain the necessary materials, it should be easy to do some experiments with growing moss in the dark, and with 90 minute day-night cycles.

Even after it dies, it might still serve a purpose: will it get digested by bacteria just as it would on Earth? Do bacteria convert it into soil?
(This post was last modified: 12-19-2014 04:45 AM by sndrtj.)
12-19-2014 04:37 AM
Find all posts by this user Quote this message in a reply
Bunsen Offline
Junior Member
**

Posts: 18
Joined: Dec 2014
Post: #6
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 03:29 AM)Mazon Del Wrote:  The moss is capable of metabolizing sucrose in the absence of light. I believe he even stated that in such an environment, the moss will actually produce CO2 instead of the standard O2.

That's exactly my point. In the dark, it consumes sugars and O2 and expels CO2 like anything else. Its ability to grow depends on having an atmosphere from which to get oxygen and into which to dump carbon dioxide.

At ambient conditions, there's about 1.2 milligrams of air in a cubic centimeter, and maybe 0.24mg of oxygen if that's normal air. Sucrose metabolism consumes, by mass, slightly more oxygen than sugar, so you're looking at each cubic centimeter of air providing the ability to burn about a fifth of a milligram of sucrose. And that's if the moss doesn't mind CO2 concentrations that would kill a lot of other things. If its metabolism is CO2 limited, it won't even get that far.

That's not going to allow much growth. Unless you provide it with a means of turning that CO2 and water back into O2 and sugar (i.e. light), I don't even know if you'd get visible growth in any practical-sized container. Fortunately, this is easy enough to test on the ground with a well-sealed container and a very dark closet.

(Hello forums, etc.; yeah I'll do an intro post later because I really should be working. Also, I see half of this has been covered by another post while I was writing. Can't be bothered to rewrite mine, though.)
12-19-2014 04:44 AM
Find all posts by this user Quote this message in a reply
Mazon Del Offline
Junior Member
**

Posts: 26
Joined: Dec 2014
Post: #7
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 04:37 AM)sndrtj Wrote:  How soon it will die is something I don't know. That is easy to test however. If I can attain the necessary stuff, I'm willing to do some experiments with growing moss in the dark, and with 90 minute day-night cycles.

Even after it dies, it might still serve a purpose: will it get digested by bacteria just as it would on Earth? Do bacteria convert it into soil?

Considering the likely volume of air that the moss has to work with (assuming the growth chamber as a whole is pressurized instead of individual capsules) (which, if we wanted to we COULD put in a higher concentration of oxygen than standard air) and the rather small size of the samples in question, Luis is of the opinion that we won't have to worry about the oxygen being the limiter of the experiment assuming a 2-4 week time period.

Chances are, unless we get enough funds for a higher orbit, we can only really expect a 2-4 week orbit time.
12-19-2014 04:45 AM
Find all posts by this user Quote this message in a reply
sndrtj Offline
Junior Member
**

Posts: 4
Joined: Dec 2014
Post: #8
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 04:45 AM)Mazon Del Wrote:  
(12-19-2014 04:37 AM)sndrtj Wrote:  How soon it will die is something I don't know. That is easy to test however. If I can attain the necessary stuff, I'm willing to do some experiments with growing moss in the dark, and with 90 minute day-night cycles.

Even after it dies, it might still serve a purpose: will it get digested by bacteria just as it would on Earth? Do bacteria convert it into soil?

Considering the likely volume of air that the moss has to work with (assuming the growth chamber as a whole is pressurized instead of individual capsules) (which, if we wanted to we COULD put in a higher concentration of oxygen than standard air) and the rather small size of the samples in question, Luis is of the opinion that we won't have to worry about the oxygen being the limiter of the experiment assuming a 2-4 week time period.

Chances are, unless we get enough funds for a higher orbit, we can only really expect a 2-4 week orbit time.

Only way to really find out is test it on Earth, which is easy enough.
12-19-2014 05:10 AM
Find all posts by this user Quote this message in a reply
Bunsen Offline
Junior Member
**

Posts: 18
Joined: Dec 2014
Post: #9
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 04:45 AM)Mazon Del Wrote:  Considering the likely volume of air that the moss has to work with (assuming the growth chamber as a whole is pressurized instead of individual capsules) (which, if we wanted to we COULD put in a higher concentration of oxygen than standard air) and the rather small size of the samples in question, Luis is of the opinion that we won't have to worry about the oxygen being the limiter of the experiment assuming a 2-4 week time period.

Can you point me toward a description of the sample chamber design? Even if it's just a link to somewhere deep in the 194-page mountain of thread.
12-19-2014 05:23 AM
Find all posts by this user Quote this message in a reply
deljr15 Offline
Administrator
*******

Posts: 102
Joined: Dec 2014
Reputation: 0
Post: #10
RE: Our dear payload, Mr Moss. It's needs and it's limits.
(12-19-2014 05:23 AM)Bunsen Wrote:  
(12-19-2014 04:45 AM)Mazon Del Wrote:  Considering the likely volume of air that the moss has to work with (assuming the growth chamber as a whole is pressurized instead of individual capsules) (which, if we wanted to we COULD put in a higher concentration of oxygen than standard air) and the rather small size of the samples in question, Luis is of the opinion that we won't have to worry about the oxygen being the limiter of the experiment assuming a 2-4 week time period.

Can you point me toward a description of the sample chamber design? Even if it's just a link to somewhere deep in the 194-page mountain of thread.

This is something that is up in the air. Sample chamber design will be greatly impacted by the topic of this thread.

That said here is rev A
MS0001 Rev A

There is also a full ring drawing that MBobrik has done. I don't have that one handy.
(This post was last modified: 12-19-2014 10:37 AM by deljr15.)
12-19-2014 05:44 AM
Find all posts by this user Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)