[PS] Liquid Water on Mars! Really for Real This Time (Probably)

On Jul/27/2018 at 6:37 AM, Jeff Findley wrote :
In article ,
says...

Planetary Society Blog

///////////////////////////////////////////
Liquid Water on Mars! Really for Real This Time (Probably)

Posted: 25 Jul 2018 09:11 AM PDT
http://www.planetary.org/blogs/emily...rs-really.html

A radar instrument on one of the oldest operational Mars orbiters has
discovered possible evidence of present-day liquid water on Mars.

This is really big news. We really, really need to explore this area to
determine how much water is there and how easy it is to get to. Water
means air to breathe and rocket fuel (CO2 from the atmosphere plus H2O
gives you liquid methane and liquid oxygen).

Jeff

I should add also that using Martian water for rocket fuel is the right
thing to do at first. But once you have a well established colony you
will want to keep water for the colony. The colonist will probably want
their colony to grow. And they will want lots of water. The more water
you have the easier it is to have an attractive colony.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.


Alain Fournier

In article , says...

On Jul/27/2018 at 6:37 AM, Jeff Findley wrote :
In article ,
says...

Planetary Society Blog

///////////////////////////////////////////
Liquid Water on Mars! Really for Real This Time (Probably)

Posted: 25 Jul 2018 09:11 AM PDT
http://www.planetary.org/blogs/emily...rs-really.html

A radar instrument on one of the oldest operational Mars orbiters has
discovered possible evidence of present-day liquid water on Mars.

This is really big news. We really, really need to explore this area to
determine how much water is there and how easy it is to get to. Water
means air to breathe and rocket fuel (CO2 from the atmosphere plus H2O
gives you liquid methane and liquid oxygen).

I should add also that using Martian water for rocket fuel is the right
thing to do at first. But once you have a well established colony you
will want to keep water for the colony. The colonist will probably want
their colony to grow. And they will want lots of water. The more water
you have the easier it is to have an attractive colony.

So start dropping comets on Mars. You're going to (eventually) need
more water than Mars has anyway. In the long run, you're going to want
to terraform the whole planet.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.

Have you run the numbers on that? Is it long enough to safely launch
people?

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

On Jul/31/2018 at 8:59 AM, Jeff Findley wrote :
In article , says...

On Jul/27/2018 at 6:37 AM, Jeff Findley wrote :
In article ,
says...

Planetary Society Blog

///////////////////////////////////////////
Liquid Water on Mars! Really for Real This Time (Probably)

Posted: 25 Jul 2018 09:11 AM PDT
http://www.planetary.org/blogs/emily...rs-really.html

A radar instrument on one of the oldest operational Mars orbiters has
discovered possible evidence of present-day liquid water on Mars.

This is really big news. We really, really need to explore this area to
determine how much water is there and how easy it is to get to. Water
means air to breathe and rocket fuel (CO2 from the atmosphere plus H2O
gives you liquid methane and liquid oxygen).

I should add also that using Martian water for rocket fuel is the right
thing to do at first. But once you have a well established colony you
will want to keep water for the colony. The colonist will probably want
their colony to grow. And they will want lots of water. The more water
you have the easier it is to have an attractive colony.

So start dropping comets on Mars. You're going to (eventually) need
more water than Mars has anyway. In the long run, you're going to want
to terraform the whole planet.

Have you run the numbers on that?
I kind of agree with you, but I would put that in the longer term category.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.

Have you run the numbers on that? Is it long enough to safely launch
people?

Only back of the envelope calculations.

Olympus Mon: diameter = 624 km, height = 25 km.
So the rail could be about 313 km long.

Mars low orbit velocity = 3.36 km/s.
Mars escape velocity = 5.03 km/s.

That means to reach escape velocity you need an acceleration of 40.4
m/s^2 (4.12 g) for 124.5 seconds on that 313 km rail.
For low Mars orbit you need an acceleration of 18.03 m/s^2 (1.84 g) for
186.3 seconds.

I'm not sure I would want to experience the required acceleration to
reach escape velocity after living a long period in the lower Martian
gravity. Martian colonist would know better than us whether that is too
risky or not. But the acceleration for low Mars orbit seems to be no
problem.

The real accelerations would be a little more than that because, at
those speeds, even the thin Martian atmosphere at a height of 25 km (a
little more than a thousandth of an atmosphere) gives significant drag.
On the other hand, I didn't take into account Mars' rotational speed
(you would place the rail on the appropriate side of Olympus Mons), but
I would expect that to be less than the loss caused by drag. So the real
accelerations are higher than the above mentioned numbers. This is only BOE.

This isn't a simple thing to do. But it isn't like, for instance that
SpinLaunch bull**** for which someone is getting some funding. It is a
workable solution. A Martian colony might find another better solution.

You can also significantly stretch the rail if you are willing to build
a support structure off the cliff at the base of Olympus Mons. But that
isn't an easy engineering project. But once you have a colony on Mars,
the lower gravity also puts it in the feasible category and not in the
wacky impractical category.


Alain Fournier

In article , says...
So start dropping comets on Mars. You're going to (eventually) need
more water than Mars has anyway. In the long run, you're going to want
to terraform the whole planet.

Have you run the numbers on that?
I kind of agree with you, but I would put that in the longer term category.

Should be some numbers he

https://forum.nasaspaceflight.com/in...?topic=38524.0

It's an often discussed topic. Essentially you need nuclear powered
rocket engines (fusion would be best, but fission would work too) so you
can go out to the Ort Cloud, find suitable objects, then use some of
their mass as reaction mass for the drive to get it to Mars. We're
likely talking many thousands of comet like objects. The advantage of
getting them from the Ort Cloud is that their volatiles haven't been
boiling off after many passes around the sun (like an actual comet).

How fast the process would be depends on how many tugs you have at your
disposal, how big they are, and how reliable they are. We're not likely
talking near term tech here. More like something a hundred years or
more into the future.

And this just gets you an atmosphere. It wouldn't likely be breathable,
so you're still going to need engineered organisms to get rid of stuff
like CO2, methane, ammonia, and etc. and replace it with O2 and H2O.
Still, if you could bring up the pressure to about 5 psi and the
temperature to something more earth like, you could walk around on Mars
with a breathing mask and suitable clothing rather than a bulky pressure
suit.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.

Have you run the numbers on that? Is it long enough to safely launch
people?

Only back of the envelope calculations.

Olympus Mon: diameter = 624 km, height = 25 km.
So the rail could be about 313 km long.

Mars low orbit velocity = 3.36 km/s.
Mars escape velocity = 5.03 km/s.

That means to reach escape velocity you need an acceleration of 40.4
m/s^2 (4.12 g) for 124.5 seconds on that 313 km rail.
For low Mars orbit you need an acceleration of 18.03 m/s^2 (1.84 g) for
186.3 seconds.

I'm not sure I would want to experience the required acceleration to
reach escape velocity after living a long period in the lower Martian
gravity. Martian colonist would know better than us whether that is too
risky or not. But the acceleration for low Mars orbit seems to be no
problem.

The real accelerations would be a little more than that because, at
those speeds, even the thin Martian atmosphere at a height of 25 km (a
little more than a thousandth of an atmosphere) gives significant drag.
On the other hand, I didn't take into account Mars' rotational speed
(you would place the rail on the appropriate side of Olympus Mons), but
I would expect that to be less than the loss caused by drag. So the real
accelerations are higher than the above mentioned numbers. This is only BOE.

This isn't a simple thing to do. But it isn't like, for instance that
SpinLaunch bull**** for which someone is getting some funding. It is a
workable solution. A Martian colony might find another better solution.

That's not nearly as bad as I would have thought in terms of
acceleration. If you limit acceleration to 3 g, it sounds like you'd be
able to get to a high Mars orbit (with a burn at the highest point, of
course, so you don't crash back down on Mars).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

On Aug/1/2018 at 7:59 AM, Jeff Findley wrote :
In article , says...
So start dropping comets on Mars. You're going to (eventually) need
more water than Mars has anyway. In the long run, you're going to want
to terraform the whole planet.

Have you run the numbers on that?
I kind of agree with you, but I would put that in the longer term category.

Should be some numbers he

https://forum.nasaspaceflight.com/in...?topic=38524.0

It's an often discussed topic. Essentially you need nuclear powered
rocket engines (fusion would be best, but fission would work too) so you
can go out to the Ort Cloud, find suitable objects, then use some of
their mass as reaction mass for the drive to get it to Mars. We're
likely talking many thousands of comet like objects. The advantage of
getting them from the Ort Cloud is that their volatiles haven't been
boiling off after many passes around the sun (like an actual comet).

I suspect you mean the Kuiper belt or the scattered disc. It would be
difficult to get an object from the Oort cloud to hit Mars in less than
20,000 years using technologies resembling what is known today. Of
course, who knows what technologies will be available in 1000 years.
Kuiper belt and scattered disc objects could be suitable for this
purpose. But even with closer Kuiper belt and scattered disc objects, I
consider that to be a long term project.

How fast the process would be depends on how many tugs you have at your
disposal, how big they are, and how reliable they are. We're not likely
talking near term tech here. More like something a hundred years or
more into the future.

And this just gets you an atmosphere. It wouldn't likely be breathable,
so you're still going to need engineered organisms to get rid of stuff
like CO2, methane, ammonia, and etc. and replace it with O2 and H2O.
Still, if you could bring up the pressure to about 5 psi and the
temperature to something more earth like, you could walk around on Mars
with a breathing mask and suitable clothing rather than a bulky pressure
suit.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.

Have you run the numbers on that? Is it long enough to safely launch
people?

Only back of the envelope calculations.

Olympus Mon: diameter = 624 km, height = 25 km.
So the rail could be about 313 km long.

Mars low orbit velocity = 3.36 km/s.
Mars escape velocity = 5.03 km/s.

That means to reach escape velocity you need an acceleration of 40.4
m/s^2 (4.12 g) for 124.5 seconds on that 313 km rail.
For low Mars orbit you need an acceleration of 18.03 m/s^2 (1.84 g) for
186.3 seconds.

I'm not sure I would want to experience the required acceleration to
reach escape velocity after living a long period in the lower Martian
gravity. Martian colonist would know better than us whether that is too
risky or not. But the acceleration for low Mars orbit seems to be no
problem.

The real accelerations would be a little more than that because, at
those speeds, even the thin Martian atmosphere at a height of 25 km (a
little more than a thousandth of an atmosphere) gives significant drag.
On the other hand, I didn't take into account Mars' rotational speed
(you would place the rail on the appropriate side of Olympus Mons), but
I would expect that to be less than the loss caused by drag. So the real
accelerations are higher than the above mentioned numbers. This is only BOE.

This isn't a simple thing to do. But it isn't like, for instance that
SpinLaunch bull**** for which someone is getting some funding. It is a
workable solution. A Martian colony might find another better solution.

That's not nearly as bad as I would have thought in terms of
acceleration. If you limit acceleration to 3 g, it sounds like you'd be
able to get to a high Mars orbit (with a burn at the highest point, of
course, so you don't crash back down on Mars).

The acceleration isn't bad, the difficult part is the air drag. At 4
km/s, even 1 millibar of atmosphere is problematic. It isn't in the
nutcase impossible to do category. But it is an engineering challenge.


Alain Fournier

In article , says...
Should be some numbers he

https://forum.nasaspaceflight.com/in...?topic=38524.0

It's an often discussed topic. Essentially you need nuclear powered
rocket engines (fusion would be best, but fission would work too) so you
can go out to the Ort Cloud, find suitable objects, then use some of
their mass as reaction mass for the drive to get it to Mars. We're
likely talking many thousands of comet like objects. The advantage of
getting them from the Ort Cloud is that their volatiles haven't been
boiling off after many passes around the sun (like an actual comet).

I suspect you mean the Kuiper belt or the scattered disc. It would be
difficult to get an object from the Oort cloud to hit Mars in less than
20,000 years using technologies resembling what is known today. Of
course, who knows what technologies will be available in 1000 years.
Kuiper belt and scattered disc objects could be suitable for this
purpose. But even with closer Kuiper belt and scattered disc objects, I
consider that to be a long term project.

You're right. I got the two mixed up. Kuiper belt is closer in and
according to Wikipedia it should contain an estimated "100,000 KBOs over
100 km (62 mi) in diameter". You start with some small ones (easier to
move in a "reasonable" timescale) then work your way up in size as the
reliability and size goes up on the tugs.

The nice thing is that the tugs would all get their reaction mass from
the Kuiper belt objects they harvest, so they're all self refueling.
They just keep bringing objects to Mars until something fatal breaks
down. Ideally, you'd make these things really, really big with their
own mineral and metal processing facilities and machine shops with all
the systems ideally being automated. The tugs would ideally manufacture
more engines, tanks, structure, and etc. so over time they could handle
bigger and bigger KBOs.

And yes, this is a very long term project. Likely many centuries at a
minimum.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.

Alain Fournier wrote on Mon, 30 Jul 2018
23:04:39 EDT:

On Jul/27/2018 at 6:37 AM, Jeff Findley wrote :
In article ,
says...

Planetary Society Blog

///////////////////////////////////////////
Liquid Water on Mars! Really for Real This Time (Probably)

Posted: 25 Jul 2018 09:11 AM PDT
http://www.planetary.org/blogs/emily...rs-really.html

A radar instrument on one of the oldest operational Mars orbiters has
discovered possible evidence of present-day liquid water on Mars.

This is really big news. We really, really need to explore this area to
determine how much water is there and how easy it is to get to. Water
means air to breathe and rocket fuel (CO2 from the atmosphere plus H2O
gives you liquid methane and liquid oxygen).


I should add also that using Martian water for rocket fuel is the right
thing to do at first. But once you have a well established colony you
will want to keep water for the colony. The colonist will probably want
their colony to grow. And they will want lots of water. The more water
you have the easier it is to have an attractive colony.


A colony will largely be able to recover and reuse most water. So the
real 'water expenditure' is for things that are leaving the colony
(like rocket fuel).


Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.


This sort of thing always looks good in theory, but I doubt you're
going to see anything like this ever actually built.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

On Aug/2/2018 at 8:42 AM, Fred J. McCall wrote :
Alain Fournier wrote on Mon, 30 Jul 2018
23:04:39 EDT:

On Jul/27/2018 at 6:37 AM, Jeff Findley wrote :
In article ,
says...

Planetary Society Blog

///////////////////////////////////////////
Liquid Water on Mars! Really for Real This Time (Probably)

Posted: 25 Jul 2018 09:11 AM PDT
http://www.planetary.org/blogs/emily...rs-really.html

A radar instrument on one of the oldest operational Mars orbiters has
discovered possible evidence of present-day liquid water on Mars.

This is really big news. We really, really need to explore this area to
determine how much water is there and how easy it is to get to. Water
means air to breathe and rocket fuel (CO2 from the atmosphere plus H2O
gives you liquid methane and liquid oxygen).


I should add also that using Martian water for rocket fuel is the right
thing to do at first. But once you have a well established colony you
will want to keep water for the colony. The colonist will probably want
their colony to grow. And they will want lots of water. The more water
you have the easier it is to have an attractive colony.


A colony will largely be able to recover and reuse most water. So the
real 'water expenditure' is for things that are leaving the colony
(like rocket fuel).

Yes. You still want a large amount of water. If some colonist like to go
water skiing of fishing... There are all kinds of things that are easier
and/or more fun with a large water supply.

Some launch systems that are wacky and impractical here on Earth become
feasible on Mars. For instance, if you have some kind of maglev rail on
the slope of Olympus Mons, you have the advantage of near vacuum at the
top and lower orbital/escape speeds.


This sort of thing always looks good in theory, but I doubt you're
going to see anything like this ever actually built.

I'm not saying it will be built. But because the rarity of hydrogen on
Mars makes rocketry more difficult, and because some of these launch
systems are several orders of magnitude easier on Mars than on Earth, I
think a Martian colony would at least make serious engineering studies
of the feasibility of some things of this kind even though they would be
ridiculous on Earth.


Alain Fournier