Scouting Mars for Landing Sites

tahanson43206 · 2021-08-30 07:56:17

For SpaceNut re #25

First, thank you for the research you did as reported in the post!

Second ... GW Johnson has provided a total of four files in support of his offer to serve as Project Leader for the Landing Site Drill. I have forwarded the files and related correspondence from the NewMarsMember portal.

Please confirm receipt of the materials.

The next step in the process is for you to forward the correspondence to Mr. Burk.

I'd like to suggest you forward the materials with a cover email explaining what we are trying to accomplish.

GW Johnson has suggested a cover letter that would be prepared for Dr. Zubrin.

You're (possibly) going to want some help with that, and there is no reason that I can see why such a letter should be composed offline and kept secret.

I'd like to suggest we (forum members with posting privileges) collaborate on the letter. It needs to be similar in brevity to the summary of a proposal just posted by RobertDyck in the Large Ship topic.

It will contain a concise description of the problem to be addressed, the means to be created, and the pathway toward launch in September of 2022.

One of my long term friends is gifted with the ability to find the essence of a complex topic and write bullet points that capture it.

We could use talent like that now.

Edit: FriendOfQuark1 is engaged with the project, but offers no guarantees anyone in the oil business will be interested or even respond.

(th)

SpaceNut · 2021-08-30 19:09:09

It terms of power thats where the price break is for cheap solar battery versus nuclear rtg as the rovers have that ability to change and sample more than one stationary site.
A falcon 9 heavy could throw the mission to mars so thats less than 50 million to configure the payload to the ride to mars.
Payload design costs for 6 year cycle to build one would hope could be cost constrained but thats dependent on fixed stationary I would think less than 200 million or a rover platform which will be closer to 800 million.

Th I took a good look at the files but did send it to James.

It has simularities to the Red Dragon sample return in many ways but with that work and others this is a mission which should be funded.

http://newmars.com/forums/viewtopic.php?id=7336
The science of a Red Dragon to mars could do as well
http://www.planetary.org/blogs/jason-da … -test.html

Sample return

Conceptual design for the Red Dragon used to carry a Mars Ascent Vehicle (MAV) and an Earth Return Vehicle (ERV).

GW Johnson · 2021-08-30 20:15:38

Spacenut:

I have created an outline for the letter proposal that TH refers to. I have written (drafted, actually) about half of that letter proposal. Will send it to TH as soon as I can get it done. I'm thinking it should be from me, you, TH, and RobertDyck. Those would be the resumes to attach.

GW

GW Johnson · 2021-08-31 09:44:44

I have confirmed that my soil test approach matches civil engineering practices, and I have identified an alternate test for softer soils that is cruder but even easier to do. The civil engineers typically use factors of safety nearer 3 when doing field tests like these. The alternate is dropping a heavy sphere from a known height and measuring the depth of the impression it makes. Failure force is potential energy divided by impression depth. Allowable force is failure over factor of safety. Use the area of the impression to convert force to bearing pressure.

For the hydraulic-powered rod that is the baseline design test, the plots of settlement distance vs applied pressure often don't have a sharp slope break to them. You have to look at the plot and make a judgement call. That requires communication with operators on Earth. So we will need communications gear capable of data and camera pictures transmission.

I'm still working on the letter concept proposal.

GW

tahanson43206 · 2021-08-31 11:27:06

There are absolutely no guarantees that go with what I am about to report ...

FriendOfQuark1 is engaged with this undertaking.

However, he has already stated that he expects nothing will come of inquiries on behalf of NewMars.

That said ... I've offered suggestions for a path forward based upon naming rights to a base/landing pad to be constructed on Mars.

A potential path forward would include:

1) Funding Large Ship for the Oil Field Crew (engineers and teleoperations personnel) to supervise equipment on the surface
2) Funding multiple delivery packages to put Dr. Johnson's equipment on the ground
3) Funding follow up construction activity using a combination of local resources and imported supplies.

Reminder .... absolutely nothing is likely to come of this, but FriendOfQuark1 is in position to inquire.

(th)

SpaceNut · 2021-08-31 20:00:36

This has a huge impact if a mission can occur not only for Mars society but for mars missions in general since a starship is so large.

We do as such have a rough estimate of what it will take, next comes the funding and hardware to achieve the goal.
Maybe there is some used equipment that would prove useful, somewhere towards making this more than a dream.

On the issue of power consumption an duration of mission that is the critical one as that dictates the level of capability for the equipment and life expectancy of the mission in the cold of night on mars to achieve the test goals.

GW Johnson · 2021-09-02 14:45:05

I have sent the draft of the letter proposal for the lander concept to Tahanson43206. That's a letter containing two illustrations, eventually with resume materials attached. As I understand it, he has forwarded these draft materials to RobertDyck and Spacenut, the four of us being the lander team. I specifically asked for RobertDyck, because he has witnessed the Canadrill in action. That, a soil bearing stress test device, and a camera, are the systems this probe is to carry. It specifically drills for buried ice, and determines the soil bearing stress at soil failure. Factored down, that soil bearing stress sizes the landing pads for any given Mars weight.

My suggestion for the next step is to get feedback from the team about this letter proposal. Send it to me here or at my email. Once refined and finished, the letter would go to Dr. Zubrin, from me on behalf of the team, probably via James Burke. We would then hope that Dr. Zubrin would show it to the likely first beneficiary (Musk's Spacex), and that from there, Zubrin and Musk could get NASA JPL interested. JPL is the obvious choice to do the detail design and readiness testing, and to work the mission.

If this thing sizes out as small as I think it might, a single Falcon-Heavy launch could send multiple probes to investigate multiple sites for a very nominal launch cost indeed. There are two questions about any particular landing site that must get answers before Spacex's Starship or any other big tailsitter can go: (1) Is there massive subsurface ice within 10 m of the surface that could be mined for propellant production, water, and oxygen? (2) What is the surface soil allowable bearing stress so that we can design adequate landing pads and legs? Both of those answers are important at the "kill a crew" level.

I look forward to getting feedback from my team members.

GW

tahanson43206 · 2021-09-02 14:58:09

This post was accidentally placed in On Orbit Refueling topic ...

As a follow up to mailings to NewMars Admins ...

The binder I put together (for word-by-word study later today) includes:

1) CV of GW Johnson dated 4-19-20.
2) Draft 2 letter to Dr. Zubrin (5 pages)
3) Image of design of lander version 2

Please let me know if you are missing any of these items.

Dr. Johnson has requested the materials be kept private for the time being.

Feedback should be provided to Dr. Johnson at his email address on record.

(th)

tahanson43206 · 2021-09-03 15:29:35

This is a follow up to a recent post in another topic (On Orbit Fuel Depot)

For GW Johnson .... I'd like to suggest replacing the name "pathfinder" with "bridge builder" in your draft letter.

For SpaceNut and RobertDyck ... please comment on this issue, if you have time.

My concern is that the term Dr. Johnson chose has "science" baggage and it's use would (potentially) mislead the audience.

"Bridge Builder" may NOT be the best alternative, so your suggestions are welcome.

The proposed probe (as described in the letter) has two missions .... they are absolutely compatible, but they are very different in focus.

If the goal is to find an entity willing to fund the project for naming rights for the landing pad, then the emphasis might be placed on one mission or the other, depending upon the interests of the entity.

(th)

SpaceNut · 2021-09-03 17:50:32

https://mars.nasa.gov/mars2020/mission/technology/

Entry, Descent, and Landing Technologies
In prior missions, the spacecraft carrying the rover estimated its location relative to the ground before entering the Martian atmosphere, as well as during entry, based on an initial guess from radiometric data provided through the Deep Space Network. That technique had an estimation error of about 0.6 - 1.2 miles (about 1-2 kilometers), which grows to about (2 - 3 kilometers) during entry.
The Mars 2020 rover mission uses various new technologies during entry, descent, and landing:
Range Trigger - for precise timing of the parachute
Using Terrain-Relative Navigation, the Perseverance rover can estimate its location while descending through the Martian atmosphere on its parachute. That allows the rover to determine its position relative to the ground with an accuracy of about 130 feet (40 meters) or better.
Terrain-Relative Navigation - to help avoid hazardous terrain
Armed with the knowledge of where it’s headed, the rover searches another onboard map of safe landing zones to find the safest place it can reach. The rover can avoid dangerous ground up to about 1,100 feet (335 meters) in diameter (about the size of three football fields end-to-end), by diverting itself toward safer ground.

tahanson43206 · 2021-09-04 09:32:13

For GW Johnson...

Per your request, here is text for the letter:

The Mars Society
11111 West 8th Avenue, unit A
Lakewood, CO 80215 U.S.A.
www.marssociety.org
https://www.facebook.com/TheMarsSociety
@TheMarsSociety
Copyright (c) 2021 The Mars Society
All rights reserved.

This data is from the announcements in the Mars Society topic ...

(th)

tahanson43206 · 2021-09-04 09:33:53

For SpaceNut ... have you heard anything back from Mr. Burk?

He's is busy with many responsibilities, but the lander proposal should be in one of the in boxes for review by now.

(th)

GW Johnson · 2021-09-04 09:38:08

The "trick" with being able to use a chute (and incorporate some steering) is to stay under about 100-or-so kg/m2 worth of ballistic coefficient. Significantly higher, and you come out of hypersonics (technically for a blunt shape, that is Mach 3, but we have to wait until it is down to chute-opening speed) too low to use a chute at all. The two 1-ton nuclear-powered rovers are right on the hairy edge of chute feasibility, requiring the Rube Goldberg skycrane rig to save weight-at-entry (ballistic coefficient).

Earlier probes were significantly smaller at half-a-ton or less, and under (or well under) the 100 kg/m2 mark. Those come out of hypersonics much higher up, and the chute has time to do some good. Bear in mind that the maximum Mach at opening for a ringsail chute is 2.5. It is 2.0 for a ribbon chute. Those two are the best designs we have for this application that are ready-to-apply technologies. The positively-inflated ballute has similar potential, but would require a lot of testing before it is ready-to-apply.

All in all, that is why I suggested limiting the probe mass to half a ton. That way, only existing ready-to-apply technologies are needed, and nothing is near the "hairy edge" of what is possible. That is the way to obtain max probability of success.

As to the name, why not call it a "landing site engineering probe"? That is exactly what it does. It determines the presence or absence, and the physical characteristics, of massive buried ice close to the surface at the site. The presence and acceptable characteristics of such ice are an engineering pre-requisite for the successful use of that ice for propellant production, and/or for life support.

The other task the probe does is to measure the soil bearing strength with an approximation to standard engineering tests used here on Earth in the construction industry. That soil strength data, and the allowable bearing pressure derived from it, are an engineering pre-requisite for sizing the landing pads on the landing legs of any large tail-sitter spacecraft we might send to the site.

All we have right now is a best-guess from Earthly data for soft fine loose sand as an approximation to regolith sand and dust with rocks scattered within it: 0.1 MPa as max allowable, which worked well for the Apollo LM and the Surveyor before it, plus earlier landers on Mars.

If this thing works out significantly smaller than half a ton, we might be able to fly 3 to 5 of them on a single Falcon-Heavy, and visit that many sites with a single launch. What a cost savings that would be! Falcon-Heavy is supposed to be able to fling at most about 5 or 6 tons to Mars.

GW

tahanson43206 · 2021-09-04 10:31:45

For GW Johnson ... re Post #38 and topic

Please consider recasting Post #38 as an appendix. It answers in detail questions that might arise at the top level.

Likewise, here is a question that might be worth an appendix entry:

In studying the surface pressure testing device, I understand that vertical movement of the piston can be measured with a sensor mounted on the exterior of the piston case. The rod can be scored with millimeter readings highlighted at centimeter crossings.

However, the pressure exerted by the piston on the soil will cause the entire mechanism to move in reaction.

Specifically, the wrist and the arm are going to find themselves bearing forces that will attempt to push both members upward.

Movement of the entire mechanism upward can be measured, but I do not see a sensor designed for that purpose.

An appendix explaining the sensors, the measurements, and the computations needed might make sense.

There must be hundreds if not thousands of papers, books and military records for this aspect of engineering, so a reference or two might be helpful for the lay reader.

***
Related but different ... the drill itself may be a source of data about the compressibility of the regolith at various depths.

If the drill is paused periodically and (somehow) pressed into the surface immediately under the bit, rough data might be secured.

If (for example) the bit hits a rock of some size, the compressibility at the surface should be near infinite (ie, beyond the ability of the instrument to penetrate).

(th)

GW Johnson · 2021-09-04 11:12:00

TH:

I just sent you a 3rd draft with some of your changes and more of my own. It does not yet have the appendix, but I like that idea. I need help culling out details from the letter to go in that appendix, which letter is now clearly too long and wordy. Spread this to the team. I need other eyes to separate essentials from details, I am too close to do this alone, because I wrote it.

Yes, to your worry that the soil test arm will bend as pressure is applied to the rod. I don't propose the potentiometer as an absolute piece of data. It supplies only relative data. We are looking for a slope break in the plotted curve of potentiometer reading vs cylinder pressure. That slope break point is where the soil has failed. We only need the cylinder pressure at that point, but we have to identify that point.

I'd rather not try to read the extension rates of the drill, because it will probably encounter rocks of multiple sizes on its way down toward ice or bedrock. Or both. That's why I tried to propose two separate devices for the two functions. If you google "soli bearing strength tests", you will find several posted articles (of varying readability) that show how this is done to a spec on construction sites. That is exactly what I did to confirm I had the essential features of the test, even if not done exactly to spec. We cannot transport tons of I-beam and ballast to Mars to do this exactly to spec.

I did want to put it on an arm, though. We need to reach around the lander and do this several times. The camera helps us not put it down on top of a visible rock, or worse, only partly upon a rock.

GW

Last edited by GW Johnson (2021-09-04 11:13:25)

tahanson43206 · 2021-09-04 11:37:24

For GW Johnson re #40 and topic ...

At some point SpaceNut and RobertDyck may free up some time to pitch in a suggestion or two...

In the mean time, I'll try to fill in as best as I can,,,

Regarding the measurement of drill progress ... OK ... that makes sense ... The time consumed per rotation of the drill shaft can be measured, and the progress through the regolith can be measured roughly by the addition of sections of drill pipe.

Regarding the surface test machine ... Modern accelerometers may be worth considering to obtain accurate data from the pressure device. The pressure will (probably) cause deformation of the surface tested, and the tip of the rod will descend. The distance the rod moves with respect to the cylinder containing the piston can be known precisely ...

Oh! I ** think ** you do not ** want ** movement! I ** think ** you are going for a pressure reading.

In other words, (please correct if wrong) you don't care how far the tip descended (there'd be a limit to that of course) ... you're trying to get a reading on how much resistance a given surface offers to the penetration of the rod.

***
The meeting of the North Houston chapter of NSS will occur in a short time ...

I'll send a note to FriendOfQuark1 asking for announcement asking for expertise in measurement for a landing pad on Mars.

The meeting leader might be willing to slip that into the proceedings.

(th)

SpaceNut · 2021-09-04 13:08:48

tahanson43206 wrote:

For SpaceNut ... have you heard anything back from Mr. Burk?
He's is busy with many responsibilities, but the lander proposal should be in one of the in boxes for review by now.
(th)

Mr Burk, he has the initial stuff but is in a holding pattern with it since we are not ready with the total brief of concept yet.
The email for Zubrin can be used by anyone for sending direct to him if we should chose to do so.
Of course adding a middle man really does not help other than to give the same files to for all to have access to them.

SpaceNut · 2021-09-04 13:14:06

Does down would pressure contain enough information for the ice detection?

If not what is the test to be to determine that we are hitting an ice layer and not just deferring rock hardness.

We are working on a stationary design correct? So sending more units that simultaneously land in the chosen field at correct distances from each other needs good guidance detection and measuring equipment.

looking forward to reviewing draft 3....

tahanson43206 · 2021-09-04 15:03:21

For SpaceNut re Post #42

Thanks for your response ... glad to know Mr. Burk is informed .... what is important here is that we do everything we can to smooth the path for this proposal. In business it is critically important to avoid surprising the person whose assistance is needed.

The goal here is to secure large scale funding. Every step taken needs to reflect that goal.

Re post #43 ... what a great question!

(th)

NewMarsMember · 2021-09-05 06:39:35

kbd512 wrote:

tahanson43206,
If GW is interested, then I can talk to some of the engineers at the company to see if any of them are interested in his project. The person who teaches mud school to the new mud engineers we hire out of college is a personal friend. He's done quite a bit of offshore and exploratory drilling. I don't know the entire extent of what he knows about hydraulics and rheology, but he's very accurate at estimating project costs because he has systematized all the inputs into drilling activities. That said, there is zero data for drilling on Mars, so you'll need wireline services to tell you what you're drilling into. Anyway, pretty much all of what little I know about drilling I learned from him. If you use any company resources, they're going to make everyone sign an NDA, and you'll probably have to recruit someone from NASA on top of that. They're unlikely to deal with individuals, no matter their credentials.
If GW's not interested, then please respect his wishes and move forward using the resources he's proposed.
GW,
If you're reading any of this and prefer to do your own work here, then know these fundamental things about drilling:
1. One of the biggest factors affecting material consumption to drill a well is generally low gravity solids removal efficiency, since that drives the required dilution rates. This is very simple to understand. You grind up enough material by failing to remove the cuttings from the fluid system and you destroy bits in short order. The better your LGS removal efficiency, the less mud you need, and the less wear and tear on equipment. The effect is pretty dramatic. You can't take any mud with you from Earth, so you'll need to source local materials for drilling operations. I expect that plain old spud mud would be fine for most practical robotic drilling, but you'll need to locate sources for things like weighting agent (unless you locate a source of barite, hematite is your best bet), water, salt, lime, emulsifiers, viscosifiers, surfactants, etc, so you also need a chemist or drilling fluids specialist with considerable experience. If you did have a small chemical plant that could make synthetic oil from Methane, that would be ideal from a mud reusability standpoint.
2. Most of what you need to know about hydraulics, as it relates to drilling, is merely to not fracture the formation you're drilling through. This is easier said than done, but you have the benefit of being able to halt drilling operations if there are unexpected losses. We don't have that luxury. Assume that Mars is a layer cake of different materials, and likely very similar to Earth. You'll likely drill through various layers of salt, shale, granite, and other minerals.
3. Apart from the operating environment, I expect that your biggest challenges will be sourcing materials for the fluid system and casing off sections, presuming this well is for more than passing scientific curiosity. Long term, corrosion and drill bit longevity will limit operations. We have fully robotic rigs with nobody on them, and those have been in operation for years. As long as you have a way to keep feeding in the consumables required for drilling and figure out how to maintain the equipment, it'll give many years of service.
Your minimum equipment list is pretty lengthy and nobody will be rolling rail cars or trucks to your drill site, so very careful planning is required. Having some way to extract broken pipe and drill bits would be a very good idea, or lots of spares. While you can drill without a fluid system, progress will be very slow, and drill bit wear will become a problem pretty fast.
Off the top of my head, you'll need grinding equipment for your weighting agent (found nearly everywhere on the surface, so collecting it shouldn't be a huge challenge), bentonite (again, not too hard to come by), pumps, fluid system tanks / mud pits, robots to collect all the ingredients in the fluid system, shakers and screens to remove cuttings (centrifuges would be nice, but not necessary; and your shakers could be integrated into the fluid system tank), drill pipe and bits, some kind of robotic pipe handling and top drive, various test apparatus to figure out what you're drilling through as you go so you don't accidentally fracture the formation, and the list goes on. You'll also need to case the well as you go, so that means sulfur and ground aggregate to form concrete. Anyway, spud mud is mostly water or seawater / bentonite clay, lime or other flocculant that you find there, salt, and a few other additives. Unless you can figure out how to use basalt fibers as LCM, that might be the only consumable you bring with you from Earth, and you only need it when you have unexpected losses, but in all drilling operations back home, having it on the rig is a hard requirement.
The first rule of drilling is to never run out of weighting agent, hematite in your case, so make sure that you don't. You can get away with quite a bit when it comes to dilution rates and playing with the additives package, but you're never getting away with not weighting the fluid system properly, so remember that.
None of this advice begins to scratch the surface of what you need to know, so you'll need to do quite a bit of reading. Maybe you've already done this, but I have no way of knowing that. There's nothing simple or easy about it, and 100% of your project is exploratory drilling. Remember what you always tell us about the percentages of art and luck involved in aerospace engineering development? This type of drilling works the same way.

kbd512 wrote:

GW,
I didn't specifically mention it, but low gravity solids removal efficiency also affects ROP, thus circulation losses. Drilling slowly nearly assures greater fluid system losses, thus more demand for power and material consumption. The fluid system does a lot of things. It cools and lubricates the drill bits, entrains and helps remove cuttings, provides the weight necessary to assure that the bore hole doesn't collapse, and prevents greater fluid system losses with the correct additives. You're not going to drill a mile down to the water / ice table without it. If you're only drilling a hundreds of feet, then you can probably get away with some kind of high strength liner, but this will be very heavy. It's better to locally source the ingredients for a fluid system. An oil-based mud is always preferable to water-based if you can produce the oil, but if not, then you're stuck with what is essentially a "throw-away" fluid system.
Also, good luck. You'll need it.

tahanson43206 · 2021-09-05 06:54:56

For kbd512 re Post #45 (copied from the Recruiting topic)

A copy of your post was forwarded to GW Johnson by email.

Is the company you're working for large enough to fund the probe?

What I have in mind is finding an oil services company large enough to be able to fund the probe, in return for naming rights to the base to be built on Mars at a suitable site found with the help of the probe.

I expect that the organization that agrees on names for features of Solar System objects must be International, with US participation.

The landing base would be a constructed feature, but whatever conventions are in place for observed features should work for constructed features.

NASA is highly likely to be involved in the feature naming process, so NASA would seem a reasonable guess about who to approach to begin the naming process.

Update ... your addendum was copied from Recruiting and appended to the main post above.

(th)

SpaceNut · 2021-09-05 09:19:47

Something to keep in mind for the mars soil is its simular to earths with regards to the seasons for hardness as we have seen with the crater wall staining's as the winter become summer. That said a test of the conditions will change from winter versus summer as the surface will become softer. We know that some areas seem to have more water per cubic meter of soil and that water is at different depths or concentrations in some areas of mars.

tahanson43206 · 2021-09-05 09:48:50

Google: who names features on Mars?

About 53,300,000 results (0.62 seconds)
The International Astronomical Union
Combined with the planets' different radii, this means Mars is nearly three times "rougher" than Earth. The International Astronomical Union's Working Group for Planetary System Nomenclature is responsible for naming Martian surface features.
Geography of Mars - Wikipediahttps://en.wikipedia.org › wiki › Geography_of_Mars

SearchTerm:Name features on Mars

Follow up .... the main web site has a page devoted to the frequently asked questions about purchase of naming rights. It deals with the issue at some length, and then offers this web site for further information.

iauinfos@iap.fr

In light of the example of NASA in naming features on Mars where it has been exploring, it is possible that securing NASA agreement with a feature name may be all that's required.

Update later on:

How are things on Mars named?
Image result for who names features on mars
Many objects on Mars, though, get their monickers through a much less formal naming process. ... "The scientists just make lists of names" within a given theme, Limonadi said, and as Curiosity comes across new objects of note on the Martian landscape, they assign names from those lists.Jun 27, 2013
How We Name the Things We Find on Mars - The Atlantic

An inquiry of NASA would appear to be in order.

(th)

GW Johnson · 2021-09-05 11:32:50

Wet soils are mushier. Ice can be hard.

GW

tahanson43206 · 2021-09-05 15:13:58

For the topic in general ...

The idea of moist terrain on Mars has been offered earlier in the topic. The human race has accumulated a great deal of ground truth over recent decades.

If someone has a bit of time and an interest in search, it would be helpful for this discussion to know how many moist soil locations have been discovered so far.

There may be reports along those lines, but I haven't seen any.

What images provided by NASA probes, and lately by the Chinese rover, seem to be showing is profoundly dry terrain with abundant rocky objects scattered about.

(th)

New Mars Forums

Announcement

#26 2021-08-30 07:56:17

Re: Scouting Mars for Landing Sites

#27 2021-08-30 19:09:09

Re: Scouting Mars for Landing Sites

#28 2021-08-30 20:15:38

Re: Scouting Mars for Landing Sites

#29 2021-08-31 09:44:44

Re: Scouting Mars for Landing Sites

#30 2021-08-31 11:27:06

Re: Scouting Mars for Landing Sites

#31 2021-08-31 20:00:36

Re: Scouting Mars for Landing Sites

#32 2021-09-02 14:45:05

Re: Scouting Mars for Landing Sites

#33 2021-09-02 14:58:09

Re: Scouting Mars for Landing Sites

#34 2021-09-03 15:29:35

Re: Scouting Mars for Landing Sites

#35 2021-09-03 17:50:32

Re: Scouting Mars for Landing Sites

#36 2021-09-04 09:32:13

Re: Scouting Mars for Landing Sites

#37 2021-09-04 09:33:53

Re: Scouting Mars for Landing Sites

#38 2021-09-04 09:38:08

Re: Scouting Mars for Landing Sites

#39 2021-09-04 10:31:45

Re: Scouting Mars for Landing Sites

#40 2021-09-04 11:12:00

Re: Scouting Mars for Landing Sites

#41 2021-09-04 11:37:24

Re: Scouting Mars for Landing Sites

#42 2021-09-04 13:08:48

Re: Scouting Mars for Landing Sites

#43 2021-09-04 13:14:06

Re: Scouting Mars for Landing Sites

#44 2021-09-04 15:03:21

Re: Scouting Mars for Landing Sites

#45 2021-09-05 06:39:35

Re: Scouting Mars for Landing Sites

#46 2021-09-05 06:54:56

Re: Scouting Mars for Landing Sites

#47 2021-09-05 09:19:47

Re: Scouting Mars for Landing Sites

#48 2021-09-05 09:48:50

Re: Scouting Mars for Landing Sites

#49 2021-09-05 11:32:50

Re: Scouting Mars for Landing Sites

#50 2021-09-05 15:13:58

Re: Scouting Mars for Landing Sites

Board footer