Author Topic: Preferred Landing Sites  (Read 18439 times)

Offline redliox

  • Full Member
  • ****
  • Posts: 1719
  • Arizona USA
  • Liked: 323
  • Likes Given: 54
Re: Preferred Landing Sites
« Reply #60 on: 03/20/2017 09:23 PM »
Not good for solar power in winter.  Not exactly exciting topography for settlers. The "fun" factor Elon oft mentions.
Perhaps SpaceX wants earliest RD missions to have easiest ice access to validate ISRU tech and then proceed to base selection forays.
Also NASA landing site priority criteria are not likely SpaceX's priorities.

First of all we don't know the conop for the mission. It might not be intended to survive the winter.  Or it might be powered down over winter.  Or the panels might be tilted to allow winter operations. We don't even know whether Red Dragon will run on solar power.  It might rely on batteries and have a surface mission that lasted only a few days.

Indeed.  The priority is seeing if a Dragon can land on Mars.  As I mentioned earlier that means it could be sent anywhere regardless of ice.

If there is to be one, extremely base and minimalistic, long-term function this lander could offer it could be to serve as a beacon.  If it can sustain a little power, this could include a Sputnik-esque radio beep or numerous reflective panels specific for laser range-finding.  Either function could give future landers something to refer to and home in on.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #61 on: 03/20/2017 10:14 PM »
More on the Space News web site.  Gives details of some other landing sites considered - Deuteronilus Mensae, Phlegra Montes and Utopia Planitia - all ruled out because they were too rocky. Interesting that Utopia, where Viking 2 landed, was considered to be unsuitable.  Indicates the surface roughness tolerance on the landing system to below Viking 2 levels.

See more at: http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/
« Last Edit: 03/20/2017 11:08 PM by Dalhousie »
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Online meekGee

  • Senior Member
  • *****
  • Posts: 7682
  • N. California
  • Liked: 3984
  • Likes Given: 822
Re: Preferred Landing Sites
« Reply #62 on: 03/21/2017 02:43 PM »
Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.
You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.

EDIT:
And yes, sites for initial RDs might be different than sites for colony.

Actually, after an initial from-orbit survey, some RDs might be used to get ground measurements in the top ranking locations
« Last Edit: 03/21/2017 02:49 PM by meekGee »
ABCD - Always Be Counting Down

Offline notsorandom

  • Full Member
  • ****
  • Posts: 1681
  • Ohio
  • Liked: 373
  • Likes Given: 87
Re: Preferred Landing Sites
« Reply #63 on: 03/21/2017 03:50 PM »
More on the Space News web site.  Gives details of some other landing sites considered - Deuteronilus Mensae, Phlegra Montes and Utopia Planitia - all ruled out because they were too rocky. Interesting that Utopia, where Viking 2 landed, was considered to be unsuitable.  Indicates the surface roughness tolerance on the landing system to below Viking 2 levels.

See more at: http://spacenews.com/spacex-studying-landing-sites-for-mars-missions/
The Viking missions were a gamble in some ways. They did not have the ability to image the surface at a high enough spatial resolution to detect all hazardous boulders. They could look at lower resolution imagery and rule out the bigger stuff but couldn't see the smaller yet still dangerous obstacles. They also bounced radar off the landing sites from Arecibo. The dispersal of the reflected signal gave them an idea how rough the surface was. In the case of Red Dragon they selected Utopia as a possible site just as the Viking people did decades before. However this time with the better imagery they dropped the site. The Viking team might very well have done the same if they had MRO and MGS imagery available too.

Offline Phil Stooke

  • Full Member
  • ***
  • Posts: 354
  • Canada
  • Liked: 195
  • Likes Given: 0
Re: Preferred Landing Sites
« Reply #64 on: 03/21/2017 04:02 PM »
Yes, they would have dropped Utopia if they had better images.  The selection - rather desperate because all other options were looking bad - was based on an unfortunate failing of image interpretation.  The best images of the site were very low contrast and resolution compared with the Viking 1 images, but they seemed to have a pervasive texture misinterpreted as sand dunes.  The assumption was that rocks produced as crater ejecta would be covered by the wind-blown sand , leaving a smoother surface. 

To clarify another point, only Viking 1's site could use earth-based radar to estimate rock abundance, and even there interpretation was very uncertain.  As Gerry Soffen said after the second landing, he was amazed that they had two successful landings.

Offline notsorandom

  • Full Member
  • ****
  • Posts: 1681
  • Ohio
  • Liked: 373
  • Likes Given: 87
Re: Preferred Landing Sites
« Reply #65 on: 03/21/2017 06:42 PM »
Right they didn't have radar for Utopia. Its been a while since I read through the site selection history. They did use radar again for Pathfinder. But shortly afterwards Global Surveyor arrived and was able to provide high enough resolution imagery for the MERs.

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #66 on: 03/22/2017 10:16 PM »
Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.
You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.


Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day.  A Phoenix type array (3.1m2) would supply 0.3-6 kwh per day.

Note these are horizontal irradiance values.  Inclined panels would achieve nearly twice this.
« Last Edit: 03/22/2017 10:41 PM by Dalhousie »
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Online meekGee

  • Senior Member
  • *****
  • Posts: 7682
  • N. California
  • Liked: 3984
  • Likes Given: 822
Re: Preferred Landing Sites
« Reply #67 on: 03/22/2017 10:41 PM »
Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.
You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.


Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day
Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.
ABCD - Always Be Counting Down

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #68 on: 03/23/2017 04:40 AM »
Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.
You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.


Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day
Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.

I don't there is any chance of anything nuclear (except perhaps RHUs) flying to Mars on the 2020 Red Dragon.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Online meekGee

  • Senior Member
  • *****
  • Posts: 7682
  • N. California
  • Liked: 3984
  • Likes Given: 822
Re: Preferred Landing Sites
« Reply #69 on: 03/23/2017 04:49 AM »
Isn't it "easy" to tip the solar panels making higher latitude almost as good. I would think dust on the panels or in the air might be a more important power consideration.
You can fix the elevation angle, but can't fix the shorter days.

I'm with RB here.  If we're stuck with solar, maximizing power is the #1 consideration. 

With water, all you need is to pass a certain threshold, not maximize - and I think you can pass that threshold in many locations.


Remember the following:

1) We don''t the power requirements, or how it might be supplied.

2) Shorter daylight in winter is balanced by longer daylight in summer.  Power usage can be adjusted accordingly. Viking 2 data (similar latitude) indicates that surface irradiance varies between 0.3 and 4 kwh/m2.  Assuming 30% efficiency that is 0.1-1.3 kwh/day
Personally, I'm hoping they'll go with nuclear, but that's a separate issue.

The total energy requirement are reasonably well known.  Tons of methane per BFS, liters of O2 per person, etc.

I don't there is any chance of anything nuclear (except perhaps RHUs) flying to Mars on the 2020 Red Dragon.
I agree.  I was talking in the context of colony siting.
ABCD - Always Be Counting Down

Online philw1776

  • Full Member
  • ****
  • Posts: 848
  • Seacoast NH
  • Liked: 473
  • Likes Given: 242
Re: Preferred Landing Sites
« Reply #70 on: 03/23/2017 03:21 PM »
The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6377
  • Germany
  • Liked: 1605
  • Likes Given: 1410
Re: Preferred Landing Sites
« Reply #71 on: 03/23/2017 03:36 PM »
The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #72 on: 03/23/2017 09:41 PM »
The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

I don't think that is a safe assumption at all. 
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Phil Stooke

  • Full Member
  • ***
  • Posts: 354
  • Canada
  • Liked: 195
  • Likes Given: 0
Re: Preferred Landing Sites
« Reply #73 on: 03/23/2017 09:49 PM »
Nor do I!  It makes sense, I guess, to put a Red Dragon with a beacon at the colony site before we start pre-landing the habitat and supplies, but allowing for a wee bit of a delay that would likely be a decade from now (minimum), so all the early dragons will be doing other things.  They are already being promoted as delivery of customer cargo, so the sites will be chosen to suit the customers for quite a while.


Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #74 on: 03/23/2017 10:38 PM »
Nor do I!  It makes sense, I guess, to put a Red Dragon with a beacon at the colony site before we start pre-landing the habitat and supplies, but allowing for a wee bit of a delay that would likely be a decade from now (minimum), so all the early dragons will be doing other things.  They are already being promoted as delivery of customer cargo, so the sites will be chosen to suit the customers for quite a while.

Agreed.  Red Dragon should be seen separate from any Mars settlement programs.  Beyond engineering tests and gaining of experience it is a way of generating income by flying paid payloads to Mars.    And there are many devils hiding in those details!
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Online philw1776

  • Full Member
  • ****
  • Posts: 848
  • Seacoast NH
  • Liked: 473
  • Likes Given: 242
Re: Preferred Landing Sites
« Reply #75 on: 03/23/2017 11:26 PM »
The thread comments can be confusing.  Some of us are referring to colony site landing sites while others are referring to RD landing sites.  The criteria could be quite different, e.g. lack of solar irradiance circa 40 degrees north might not be a big issue for a RD mission, but could be a big negative for an all-seasons colony, assuming no nukes.

IMO it is a safe assumption that a RedDragon landing site would be chosen to be a likely colony site.

Maybe not for a 2018 like mission where landing was the main/only goal. But for 2020 missions. If the choice was right, then a first ITS can use a radio beacon from that landing to home in on.

Way, way too early for SpaceX to have selected a colony site.  A needless rush.  RD MAY for example pick an "ice near the surface" site simply to test ISRU methods most easily. 
With Musk's statement that multiple RDs will transit to Mars each opposition once EDL, etc. is flight proven, there are lots of opportunities to validate, compare & contrast multiple colony sites via ground truth RD landings.
Only Elon believes that ITS will start flying in the early 2020s, so there are many oppositions next decade to fly many RD missions.

Bottom Line: RD site & colony site criteria for the next oppositions may be quite different.
They will in time converge.
« Last Edit: 03/23/2017 11:28 PM by philw1776 »
“When it looks more like an alien dreadnought, that’s when you know you’ve won.”

Offline Dao Angkan

  • Full Member
  • *
  • Posts: 157
  • Liked: 34
  • Likes Given: 24
Re: Preferred Landing Sites
« Reply #76 on: 03/24/2017 02:13 AM »
Even for a colony the landing site might be some distance from the colony site. For example the possible Red Dragon Amazonis/Arcadia landing site offers a large flat plain for travelling far further south overland.
« Last Edit: 03/24/2017 02:14 AM by Dao Angkan »

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6377
  • Germany
  • Liked: 1605
  • Likes Given: 1410
Re: Preferred Landing Sites
« Reply #77 on: 03/24/2017 06:47 AM »
I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2068
  • Liked: 255
  • Likes Given: 309
Re: Preferred Landing Sites
« Reply #78 on: 03/24/2017 09:58 AM »
I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

When it comes to timelines, he talks nothing but nonsense. 

There is also a huge difference between a Red Dragon mission which could feasibly launch in 2020 (although may well slip to 2022 based on record) and the ITS fantasies.

So let's stick to Red Dragon landing sites.



« Last Edit: 03/24/2017 10:08 AM by Dalhousie »
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27022
  • Minnesota
  • Liked: 6914
  • Likes Given: 4875
Re: Preferred Landing Sites
« Reply #79 on: 03/24/2017 12:15 PM »
I just argue from the timeline given. I am aware that the timeline will slip, like everybody is. But presently they are working towards it. That does not leave any room. 2020 for Red Dragon. 2022 for the unmanned ITS. That timeline means the 2020 Red Dragons are direct precursors for the first colony flights. Remember there is the need to build substantial capacity for fuel production at that first landing site. They don't do that randomly for any number of locations until they like one for settlements.

That does not mean they would not abandon the first site if it for some reason turns out to be untenable but it would be a major and costly setback.

I don't just assume Elon Musk is only talking nonsense about his plans.

When it comes to timelines, he talks nothing but nonsense. 

There is also a huge difference between a Red Dragon mission which could feasibly launch in 2020 (although may well slip to 2022 based on record) and the ITS fantasies.

So let's stick to Red Dragon landing sites.
Red Dragon is hardly less of a fantasy. SpaceX will pursue ITS until it goes bankrupt, at which point Red Dragon missions will stop, too.

Not long ago, folks would say VTVL and Red Dragon were fantasies. And ITS is the reason for these Red Dragon missions anyway.
« Last Edit: 03/24/2017 12:16 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0