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#76 2019-09-13 17:14:30

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

GW Johnson wrote:

I took a closer,  more nuanced look at nuclear propulsion thermal rocket propulsion

Thank you

GW Johnson wrote:

I looked at some 6 different implementations ... two closely-related open-cycle gas core concepts

Ooo! Ooo! Woo hoo! You said open-cycle gas core! (I'll try not to embarrass myself.)

GW Johnson wrote:

All of this begs the question of the surface-to-orbit-and-back ferry at Mars (and Earth).

I suggested the SpaceX Starship. Not Starship 2, but the original Starship that they're working on right now. Their design would be two stage. The first stage would not enter orbit; it would return to the launch site and land the same way as the first stage of Falcon 9 or Falcon Heavy. The upper stage would have propulsion stage integrated with passenger compartment. It would be refuelled in Earth orbit before proceeding to Mars. Once on Mars it would be refuelled by ISPP to return to Earth. My idea is the passenger shuttle is the passenger version of SpaceX Starship; it's 2 stage on Earth, single stage on Mars. Propellant would be transported by the tanker version; again 2 stage on Earth, single stage on Mars.

bfr-stagesep-879x485.jpg

BFR-2018-Mars-landing-SpaceX-crop.jpg

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#77 2019-09-14 00:05:35

kbd512
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Re: Large scale colonization ship

My idea of a passenger shuttle for both Earth and Mars is an electromagnetically accelerated vehicle, roughly the size of a small business jet, that uses an external ground or space-based power system to heat plain old Hydrogen to temperatures that produce specific impulses matching NERVA for the final phase of acceleration to orbital velocity.  A system like this may not be as sexy as a monstrous rocket with a 1,000t payload, but it keeps popping payloads into orbit like a Pez dispenser and in the space of a year we'll have delivered more tonnage to orbit than in all the previous decades of space flight combined.  It also does this with minimal power input, roughly 28kWh/kg.  A small nuclear reactor can deliver many multiples of the required input power, storing it in flywheels that then release the stored energy at the rates required for the initial acceleration.  Approximately half as much energy is required on Mars since orbital velocity is approximately half of what it is on Earth.  Compared to all other feasible solutions, electrification and microwave power transmission represents the lowest cost, lowest risk, and highest probability of making space flight routine and uneventful.

Once the payloads are in space, nuclear fusion achieved with power supplied by small fission reactors is the way to go.  We already achieve fusion each time we try it, we just can't make the energy conversion efficient enough to obtain a net gain in terms of electrical power output from the process.  The very best part of this in-space propulsion scheme is that it involves doing things we already know how to do and are 100% successful in doing, namely making superheated plasma from fusion, losing containment of the plasma- this time intentionally, and never generating a single watt of electrical power- just pure thrust.

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#78 2019-09-14 07:44:38

tahanson43206
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Registered: 2018-04-27
Posts: 2,177

Re: Large scale colonization ship

For kbd512 re #77

There's a reason I call up NewMars forum first thing after powering up "Old Reliable" here .... It's the hope of finding something like your post here to inspire thoughts and sometimes actions throughout the day.

Rather than offer suggestions, in an arena where you are far more qualified, I'm going to adopt a pull strategy.

Please expand a bit on the phrase "electromagnetically accelerated"

I'm pretty sure I've seen reports of studies done and actual experiments performed on delivery of electromagnetic energy through the atmosphere from a ground station to a moving vehicle.  Radar painting of an airplane is a common example, though there may be many more.

Does your concept employ more than one method, as the vehicle moves through phases of flight, from launch through LEO?

Thanks for your contribution this morning!

(th)

Last edited by tahanson43206 (2019-09-14 07:45:11)

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#79 2019-09-14 09:55:25

GW Johnson
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From: McGregor, Texas USA
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Re: Large scale colonization ship

On the assumption that some sort of orbit-to-orbit Earth-Mars transport design can be worked out (what this thread is about),  there is the problem of the ferry required to get stuff from Earth's surface to Earth orbit (and back),  and there is the problem of getting stuff to and from Mars orbit at that end.

Consider:  the Spacex "Starship" is first and foremost a large-payload transport from Earth's surface to low Earth orbit.  It uses a recoverable booster to deliver payload to orbit in 100+ ton lots,  without any refueling.  One flight,  one 100+ ton payload delivery.  I am not aware of how much it can transport down from orbit,  but for colonization,  that is not so relevant (later on with interplanetary trade it is). 

If one believes the numbers for "Starship",  this is an impressive ferry.  It could easily transport a payload to a colonization vessel in Earth orbit in those 100+ metric ton lots.  I think we have that end covered.  1 flight for a 100 ton colony ship payload,  10 flights for a 1000 ton colony ship payload,  etc.  Cost per ton delivered will be whatever it results for actual "Starship" operation.  We won't know what that really is until it has been tested and begins regular flights.

Now,  what about at Mars?  What might "Starship" do for us,  to unload that colony ship and bring its payload to the surface?  I took a look at that with data for low Mars orbit (3.55 km/s),  a small landing burn allowance (Mach 1-ish 0.33 km/s),  factors on the delta-vees,  and a generous rendezvous allowance on-orbit at Mars (1 km/s).  The factors were 1.02 for gravity and drag to reach orbit,  1.5 on the min landing allowance,  and 1.0 on the rendezvous allowance. 

For the ship,  I used the published figure for ship inert mass 85 meric tons (about which I have serious doubts until I see it actually fly at that inert weight),  and a "typical" figure for vacuum Raptor performance 350 sec Isp.  It holds up to 1100 metric tons of propellant that must be produced on Mars from local materials,  and in quantities and rates to support the flight rates. 

I did the mass-ratio-effective dV thing to estimate performance vs payload and propellant load,  done as the same large payload masses transferred both ways (up,  and down).  Those results were surprisingly good: 

payload m.ton     propellant load, m.ton
100                    650
200                    990
234                    1100

This is driven by the low inert mass reported so far for the "Starship" design.  If you believe that really will be achieved,  then it looks like a "Starship" stationed on Mars,  and locally refuelled there,  can well serve as a reusable ferry for colonization ships sent to low Mars orbit.  That covers the Mars ferry needs for an orbit-to-orbit colonization ship. 

Now,  the vast bulk of Mars's surface resembles fine, loose sand.  Here on Earth,  safe bearing load pressures for fine,  loose sand (in many decades long civil engineering experience) is 0.1 to 0.2 MPa.  Period.  You must use the lower figure to design things in the absence of real soil test data from your actual site.  So you must use the 0.1 MPa figure. 

I looked at various ignition masses more-or-less appropriate to the Mars orbital ferry role,  calculated weights at Mars 0.384 gee,  and divided by the soil bearing strength to find the required tail fin landing pad areas in order to support rough-field takeoff operations.  They fall in the 45-55 square meter range.  That's just the nature of rough field operations,  and it will have to be dealt with in the "Starship" design.  They currently have a single handful of square meters,  at best.  Spacex will have to address this issue,  sooner or later.

The final thing to worry about is the "Starship" heat shield.  I presume there will be PICA-X ablative on the windward surfaces,  nosetip,  and leading edges.  Entry from Mars orbit is about half the speed from Earth orbit,  so the heat shield will likely fly 3 or 4 times before being used up.  Maybe more,  maybe less.  There will have to some way to refurbish this on Mars (in the cold and near-vacuum) using materials brought from Earth.  Spacex will have to eventually address this issue as well,  if they use the vehicle for this purpose.

That still begs the question of landing stability,  since the vehicle is tall and narrow,  and the gear is tripod,  not quadruped.  Landing fields will have to be very level,  very flat,  and very free of big boulders.  Period.  Spacex will have to face up to that issue eventually,  regardless of what purpose "Starship" gets used for,  on Mars.

That'd the problem with being a real engineer.  I tend to worry about the damndest real-world things.  How very inconvenient!

All that being said,  it looks to me like "Starship" would make a very good ferry at both ends of the Earth-Mars journey.  That means we are NOT barking up the wrong tree looking at orbit-to-orbit colonization transports. 

GW

Last edited by GW Johnson (2019-09-14 10:08:56)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#80 2019-09-14 12:55:54

kbd512
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Re: Large scale colonization ship

tahanson43206,

Yes, this scheme involves using different types of electromagnetic and microwave propulsion technology to achieve orbital and escape velocity.

The orbital transport system uses EMALS (basically, a glorified rail gun with lower acceleration forces; the same system that launches our fighter jets off the end of Ford class aircraft carriers) for the "boost" phase of the flight, but provides constant acceleration for a greater length of time on a circular track.  For example, this 4g space launch "cat shot" (this is peak acceleration on those naval catapults and we put ordinary civilians through this ordeal on a routine basis without a second thought) would generate a speed of approximately Mach 7 in 60 seconds.  So, think of this circular EMALS launch catapult as the "first stage".  These circular launch loops would be located on the east and west coasts, possibly at or near existing facilities like Cape Canaveral and Vandenberg.

After the "sled" releases the spacecraft, a high power microwave transmitter array will transmit power to a heat exchanger plate on the bottom of the spacecraft, making the spacecraft itself the "second stage" if you will, to accelerate Hydrogen propellant at roughly the same velocity as NERVA (slightly higher, actually) and spacecraft to orbital velocity.  A secondary lower power array, possibly located in Europe or Africa, later in orbit for maximum flexibility in launch trajectories, would circularize the orbit.

Once you achieve a stable orbit, you dock with and transfer to a purpose-built spaceship that stays in space and provides interplanetary transport services using fusion propulsion.

NASA / Dr Slough / Dr Kirtley / et al, found that while the fusion driven rocket as they originally designed it was technically feasible, they could drastically improve the life span of the electromagnetic coils that initiate fusion by accelerating a metal foil clad D-T pellet / marble to 10km/s through a much lower constant force electromagnetic field, rather than imploding a thin metal foil liner around the D-T pellet at 10km/s, which required a 1.8GJ surge of electricity to accomplish.  Either way, the end result is an exponentially increasing electromagnetic field around the D-T pellet that achieves fusion because it happens so fast.

The old and new fusion drive methods use implosion, somewhat akin to the way nuclear weapons use implosion from plastic explosives and metal liners to achieve uncontrolled fission reactions- albeit through entirely different methods and with entirely different results, using hypersonic acceleration / crushing of the metal around the pellet.  They do this without exceeding the plastic deformation limits of Aluminum (the test metal used in the experiments, lots of thrust but not very good for Isp) / Lithium (best Isp) / Beryllium (better thrust and acceptable Isp) / other light metals (as the metal goes up in atomic mass thrust goes up and specific impulse goes down considerably, so you can "gear" these things by using combinations of different metals to achieve "more torque in low gear and more horsepower / better fuel economy in high gear").

Using implosion to achieve fusion is a very old concept and very well tested, but nobody has had any luck getting electrical power from it.  We're not using if for electricity at all, so we don't care about that.  We're just trying to get a "Big Bang" for minimal mass input.  By momentarily achieving fusion and intentionally allowing the superheated metal plasma to escape out of the magnetic nozzle we can actually do that.  What we absolutely cannot do is meaningfully improve the efficiency of chemical reactions and even Hydrogen heated by a nuclear reactor fails to provide a propulsion solution with the propellant mass efficiency required for colonization / civilization level mass movement of people and cargo between planets.  These legacy technologies certainly have their uses, but interplanetary transport of millions of people is not one of them.  They're acceptable for exploration purposes and that's about it.

So, net net is that this new method achieves the same outcome with far less wear and tear on the coils and switches.  It does require modestly higher mass than the original concept because it employs a laser for acceleration and a tube of electromagnetic coils that supplies a constant electromagnetic force to "crush" the pellet as the laser rams it through the electromagnetic field at 10km/s.  That said, it's also not absurdly over the top in terms of mass.  It's about 3 times the mass of the previous concept, which was 15t.  The existing Falcon Heavy rockets could carry the test articles into space, for example.

I'm more interested in methods we can use into perpetuity, which are also truly scalable, than I am about what could possibly work well enough to get started.  We could've built a 1,000t payload "big dumb rocket" decades ago.  Nothing about the technology required was lacking by the 1970's.  However, the relative inefficiency of such methods was staggering and that's why it was never pursued.  Even if we did pursue it, after we put our 1,000t ship into orbit using Sea Dragon, then what?  We couldn't send it anywhere else on any routine basis for anything approaching a reasonable cost (on orbit fuel transfer was just a paper concept back then), so where would that leave us?  Right back where we started?  That's why we needed more efficient propulsion methods that simply didn't exist back then.  Even NERVA was just a means to an end for exploration purposes.  Even if we used it to go to Mars, such missions would've been flags and footprints and nothing else.  NERVA also had a lifespan measured in hours, after which it had to be disposed of by flying it into the Sun.

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#81 2019-09-14 14:24:58

RobertDyck
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Re: Large scale colonization ship

I had started this with a calculation: 4 RPM @ Mars gravity resulted in a ring too small, 2 RPM was too big, 3 RPM resulted in a ring about the same volume as Starship 2. That is with a ring width of 14m. But using 4 metre long cabins with window at one end, door at the other end, cabins on either side of the isle, with 1.5 metre wide (59") corridor, and 2 corridors along the length (circumference) of the ring. That means half the cabins will be "inside" with no window, but will have a large wall-mounted smart TV that can be "tuned" to any one of various cameras mounted on the outside of the ship. This required expanding the ring to 19 metres wide. With 2.4 metre (8 foot) ceiling, that gives the ring 10,475 cubic metres, floor area 4,507.8 square metres (48,521.65 square feet). Elon said Starship 2 would have 8,000 cubic metre habitable volume, so this is a bit bigger.

What if we increased rotation rate for Earth gravity instead of Mars gravity? Instead of 3 RPM, that would require 4.8665 RPM. For the very same ship. It would have to be strengthened to withstand the forces of 1G instead of 38%, but same size. Is that rotation rate tolerable? Some here have argued for Earth gravity. Interesting that it can be achieved so easily.
Centrifugal force calculator

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#82 2019-09-14 21:48:03

SpaceNut
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Re: Large scale colonization ship

Gw the starship once in orbit can not come back down since it can not retro burn it would require fuel being sent up before it can come down for that reason for a landing plus it can not do the ocean at all....

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#83 2019-09-14 23:06:44

RobertDyck
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Re: Large scale colonization ship

Elon Musk's presentation on BFR from September 2018. This explains how Starship (as it's now called) works. BFR was going to be carbon fibre composite, Starship is stainless steel, but dimensions remain the same. Click image for YouTube video.
hqdefault.jpg?sqp=-oaymwEjCPYBEIoBSFryq4qpAxUIARUAAAAAGAElAADIQj0AgKJDeAE=&rs=AOn4CLCWEonQQ4uKps8naGlTCZbQknKVaw

The point is Starship is designed to land. It's designed to land on Earth, the Moon, and Mars. It lands on its tail the same way first stage of Falcon 9 lands.

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#84 2019-09-15 10:01:23

GW Johnson
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From: McGregor, Texas USA
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Re: Large scale colonization ship

RobertDyck is correct.  That presentation shows the big booster and second stage spacecraft flying to orbit with a big payload,  but not burning up all the propellant.  The nested inner tanks contain the return propellant.  No on-orbit refueling is required at all for this.  To return to the Earth's surface,  it makes a small de-orbit burn,  then aerobrakes  at AOA in the vicinity of 40 degrees off the wind axis to roughly Mach 3 (about 1 km/s) at roughly 130,000 feet (40 km),  at a final moderately steep path angle downward (20-40 degrees below horizontal).  The initial entry path angle is less than 2 degrees below horizontal.

From there it increases AOA to about 90 degrees relative to the wind,  and "belly-flops" vertically downward,  slowing by dead-broadside aero drag to low subsonic as it encounters denser air below 20,000 feet (6 km).  As it approaches the surface,  it pitches up to tail-first (AOA ~180 degrees),  and makes its retropropulsion touchdown burn.

Landing on Mars is similar,  but also different.  Earth entry is at ~8km/s,  while Mars entry from the interplanetary trajectory is ~7.5 km/s,  so conditions for heat shield design are comparable,  and not the most stressful it must endure.  There is no entry burn at Mars.  It aerobrakes the same way it does at Earth,  at modestly-high AOA.  Initially,  this is downlifting to prevent bouncing off while moving faster than Mars escape.  Later,  under Mars orbit speed,  it rolls (at modestly-high AOA) to uplift,  to prevent the trajectory from bending downward too soon.

It comes out of hypersonics (Mach 3-ish,  about 1 km/s velocity) in the thin air at conditions very similar to that same point during Earth entry.  It's just that the thin air end-of-hypersonics point occurs roughly 5 km from the surface,  and the trajectory has bent downwards some.  It does not do the "belly flop" on Mars,  instead it continues lifting at AOA 20-40 degrees to bend the trajectory back upwards before impact,  while slowing below Mach 1 (about 0.3 km/s) as it finally climbs.

They steepen the climb to vertical,  at which point the nose is straight up just as the velocity zeroes,  still under 10 km altitude (probably closer to 5 km,  with the bottom-out near 3-4 km).   Spacex shows no propulsion until this point,  when they fire up the engines using the propellant in the inner nested tanks.  The ship tail-slides in retropropulsion to its touchdown.

I think on low density days and on the higher elevations,  they will have to fire up the engines earlier,  so as to add thrust power to help the lift bend the trajectory upward to the vertical tailslide point without smacking the surface at the bottom-out point. It is considerations like that which induce me to recommend at least factor 1.5 more touchdown delta-vee capability than nominal conditions would suggest.

Coming back from the moon to Earth,  it hits the atmosphere at near 11 km/s,  far more demanding on the heat shield.  It uses 40-degree AOA aerobraking,  initially downlifting until below ~8 km/s,  then uplifting to prevent the trajectory steepening downward too soon.  As from Earth orbit,  the end of this is Mach 3-ish (near 1 km/s),  at about 130,000 feet (40 km),  and something like a 20-40 degree downward path angle.  From there it does the same "belly-flop" to low speed and altitude,  then the same pitch-up to tail-first for retropropulsion touchdown. 

Coming back from Mars to Earth is very much like coming back from the moon.  The only difference is an even higher speed at entry interface.  This is nominally about 12 km/s,  but can easily be higher,  depending upon the planets' orbital positions,  and how fast a trajectory home was flown.  The worst case max is near 17 km/s.  THAT is what designs the heat shield,  by the way!

Refueling on-orbit with tanker flights is required to go anywhere but low Earth orbit (which requires no refueling at all).  Pretty much a full propellant load is required to take a max payload to the moon or to Mars.  Unlike Mars,  from the moon no refueling is required to leave the moon for home. 

The situation on Mars is stark:  if local propellant production doesn't work as advertised,  you are stuck there till you die. You land with essentially dry tanks. 

The technological status of this thing is not as advanced as some folks seem to think.  A plain exposed stainless steel craft can do suborbital flight tests.  It will require a minimal windward-side heat shield to make an orbital flight and return.  They are a long way yet from a heat shield design fit to return from the moon,  much less from Mars.  It WON'T be bare metal,  that I can guarantee!

They are also quite far from a practical landing pad design on the back edges of those fins.  What they have can only operate off a reinforced concrete slab or a big thick (and very flat!!!) slab of solid rock.  It cannot make an emergency rough-field landing anywhere on Earth,  because those fins will sink into the ground,  unevenly.  It WILL topple over and explode.  Which means they are a long way off from having the rough field landing capability they show for Mars.

It's nasty little inconvenient things like these,  getting in the way of grand and valid concepts,  that makes Musk time about factor 2 longer than real time.

GW

PS for RobertDyck:  what's in that centrifugal force calculator is exactly what I re-arranged into my favorite form:  gees = (R, m/55.89m)(N,rpm/4rpm)^2.  I used the physics equations to get radius R=55.89m at exactly 4 rpm for exactly 9.8067 m/s^2 (one gee). It is fairly widely accepted that people off-the-street can tolerate long-term exposures to 4 rpm without getting motion sick.  It takes training and acclimatization to tolerate 8 rpm long-term (days+,  which is essentially steady-state).  Higher speeds in the 12-16 rm range can be tolerated only short-term (minutes).  At 16-20 rpm,  even for only seconds to a minute exposure,  you get enough blood pooling in your legs to cause you to faint if you stand up.  This is the stuff they investigated with centrifuges in the 1950's.

Last edited by GW Johnson (2019-09-15 10:54:48)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#85 2019-09-15 11:33:59

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,898
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Re: Large scale colonization ship

Perhaps this will help.
NASA's InSight Uncovers the 'Mole'
8455_PIA23308-web.gif

Part of an instrument called the Heat Flow and Physical Properties Package (HP3), the self-hammering mole is designed to dig down as much as 16 feet (5 meters) and take Mars' temperature. But the mole hasn't been able to dig deeper than about 12 inches (30 centimeters), so on Feb. 28, 2019 the team commanded the instrument to stop hammering so that they could determine a path forward.

This means Mars is loose sand over solid permafrost. After about 12 inches deep at the location of InSight. Construction workers in Alaska studied permafrost, because they have to, that's their ground. What is the hardness of permafrost at -60°C? I believe the average temperature on Mars surface is actually -63°C, but that will vary from site to site, and with season. Ground temperature near the surface will be average temperature at that location. I read an article about constructing in Alaska, it claimed permafrost is as hard as rock. Does this give Starship a more solid surface to land on?

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#86 2019-09-15 17:18:44

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,827
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Re: Large scale colonization ship

What it really means is that the JPL guys know a lot less about Mars's surface and immediate subsurface conditions,  than they thought they did.  Where is the real surprise in that?  Since when has that NOT been true?

As for permafrost,  yes,  that is hard stuff,  but I suspect you cannot hang your hat on the 12-inch figure.  That will vary all over the map,  just like it does here.  Ask any Eskimo.  They know a hell of a lot more about this topic than any JPL guy.  Much less any Spacex guy.

With a variable penetration depth to any hard stratum,  just how are the landing pads of a Spacex "Starship" not to penetrate unevenly,  precipitating the topple-over and explosion that I said?  If not on landing,  then on refilling for takeoff,  when weights on the landing pads are something like 6 times greater than at landing?  Especially with tripod gear instead of quadruped gear. 

All of this is well-established physics from other fields,  particularly 3-wheel cars and tractors vs 4-wheel cars and tractors.

Guys,  this is nothing but common sense and hard data.  Ignore the promotional ads.

GW

Last edited by GW Johnson (2019-09-15 17:24:04)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#87 2019-09-15 18:05:42

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,898
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Re: Large scale colonization ship

GW Johnson wrote:

Since when has that NOT been true?

True

GW Johnson wrote:

Ignore the promotional ads.

35eb091115931f23473c75a7c8e0d069.gif

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#88 2019-09-15 18:24:31

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,827
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Re: Large scale colonization ship

Hi Robert:

Mostly,  we are on the same page. 

Have you seen what I posted about Colony Ships and Nuclear Thermal on "exrocketman"? 

I also took a look at Spacex's "Starship" as a surface-to-orbit-and-back ferry at Mars as well as at Earth.  It doesn't look too bad,  except for there being no "way out" if the vehicle malfunctions.  Have not yet posted about that.

The latest is "Mars Mission Outline 2019",  posted yesterday. 

GW

Last edited by GW Johnson (2019-09-15 18:25:46)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#89 2019-09-15 19:00:02

SpaceNut
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From: New Hampshire
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Re: Large scale colonization ship

The increased fuel load from the original of 1100t to 1200t I missed..which accounts for boil off for mars...so that it can land.

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#90 2019-09-15 19:14:31

Oldfart1939
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Registered: 2016-11-26
Posts: 1,805

Re: Large scale colonization ship

The guys at JPL are "professional scientists;" they unfortunately know not that they know not!
At SpaceX, they are more experiment oriented, but I sure wish they had NOT cancelled Red Dragon landers. They might have revealed something about the surface of Mars and it's ability to support loads.

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#91 2019-09-15 20:35:42

RobertDyck
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Re: Large scale colonization ship

Mars Direct was designed to send the ERV first, unmanned. Only when propellant tanks were filled, ready to return home, would astronauts leave Earth. Starship will not have that luxury. Yes, Starship is dependent on refuelling via ISPP. I wouldn't use Starship for the first exploratory missions, I would use something smaller, eg Mars Direct. This would allow building a propellant depot with enough propellant to refuel Starship before it leaves Earth.

Or I could give a flippant answer. International Rescue:
3d0dd04152ebc70c2c28b40ff4e22f20.gif

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#92 2019-09-15 21:35:35

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

Quick calculation. You could launch a rover the size of Spirit or Opportunity (Mars Exploration Rover, MER), with a subsurface drill to explore the site before sending a human mission. MER was launched on Delta II Heavy, which has been discontinued. To stick with SpaceX hardware, you could launch it with Falcon 9 Full Thrust, with first stage recovered on a drone ship. This would require both the normal Falcon 9 upper stage, and a Centaur upper stage. The LH2/LOX upper stage is required. The only alternatives would be Antares, Atlas V (501), or Falcon Heavy (recovered).

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#93 2019-09-15 21:55:07

Oldfart1939
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Registered: 2016-11-26
Posts: 1,805

Re: Large scale colonization ship

Robert-I would agree that sending starship to Mars without a pioneer type lander is both foolhardy and dangerous. My system in concept, would utilize a Red Dragon capsule system and have an onboard drilling system with adequate power to core drill and retrieve samples  to a depth of 16 meters. Not some cackamamie drill designed by a bunch of astropyhsicists, but designed by petroleum geologists in need of more realistic samples for analysis by stratigraphy.My concept system would go straight down the centerline of the dragon capsule with a monster power drill of say 5.0-7.5 cm diameter. Bring up core samples that might be 2-4 meters in length. Base the average sample hardness and density of arctic permafrost as the softest sample encountered and maybe to Travertine as the most resistant. There were going to be several Red Dragons sent, so send a couple to different locations and get some real data.

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#94 2019-09-15 22:52:44

RobertDyck
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Re: Large scale colonization ship

Oldfart1939, you realize I'm thinking of CanaDrill. I attended a workshop hosted by the Canadian Space Agency in 2005. The president of CSA at the time gave a presentation of a mission he wanted. It would have been a Mars rover about the size of Spirit or Opportunity but with a multi-segment drill. It would use 1 metre long drill pipes, 10 pipes, so could drill up to 10 metre depth. Well, leave about half a metre out of the ground for the drive mechanism to grapple the pipe. It would include sample handling on the back of the rover, and instruments to examine the core samples.

This wasn't some cockamamie design by a bunch of astrophysicists, it was designed by an institute that developed technology for mining. The Northern Centre for Advanced Technology (NorCAT) is located in Sudbury. There's a major nickel mine there. They also mine various other metals, including platinum. Several mining companies are in the business of hard rock mining. NorCAT supports them.

This drill was a dry drill, no liquid lubricant. And it used an electric drive motor. They tested it with a sample box with 2 metre depth of a mix of materials: hard rock, soft rock, loose stones, gravel, sand. The drill operated slowly so they left it to run for one test. It went through everything, and drilled through the plywood bottom of the box.

Unfortunately Parliament did not agree to fund it.

News stories at the time, with images of the drill prototype: (click image for news story)
norcat_prototype2_030704.jpg norcat_prototype030704.jpg

Artist's concept of Mars lander using the drill. Note: the CSA president wanted a rover. (click for CSA website in French)
Canadrill-1_hr.jpg

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#95 2019-09-16 13:40:50

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Large scale colonization ship

Mars Homestead Project was established to design the first permanent human settlement. Assumption was science / human exploration missions would come first. Since the scope was to design the settlement, not a spacecraft, we assumed settlers arrive on Mars Direct habitats. 12 settlers arrive in 3 habitats, 4 each. A 4th habitat sent without crew but with life support as a backup. It would use in-situ resources. Once complete, the crew would double the size to support 24 people. Then that would manufacture resources to accept the first 100. I choose to assume that is complete before the first SpaceX Starship arrives. That means there is habitation space, although limited, as well as construction materials, equipment, food, life support, and propellant.

In this image, look for the cluster of 4 cyclinders with a red ring around the top. Those are Mars Direct habitats. And that gives an idea of scale.
normal_MHP-4FC-Image022.jpg

normal_MHP-4FC-Image023.jpg

normal_MHP-4FC-Image029.jpg

normal_MHP-4FC-Image024.jpg

normal_MHP-4FC-Image026.jpg

Notice the atrium has Roman arches. We discussed groin vault, but I believe the artist depicted cloister vault. Very Roman. A worker in the greenhouse has a Canadian flag on her shoulder. And the apartment is shown with hardwood floors made of bamboo, Chinese wall hangings and vases.

The woman's belt has a flip-phone, but realize the date of this art work is 2005. The first smartphone was iPhone, it came out in 2010.

A more realistic rescue vehicle:
normal_MHP-4FC-Image025.jpg

normal_MHP-4FC-Image027.jpg

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#96 2019-09-16 19:42:00

SpaceNut
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Re: Large scale colonization ship

A drill was also part of the 2020 http://newmars.com/forums/viewtopic.php?id=7014 Had an initial prototype hardware can package up to 31 drill core samples

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#97 2019-09-17 01:30:56

RobertDyck
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Re: Large scale colonization ship

SpaceNut wrote:

A drill was also part of the 2020 http://newmars.com/forums/viewtopic.php?id=7014 Had an initial prototype hardware can package up to 31 drill core samples

This was part of the same stupid idea. Robert Zubrin wrote about this. The idea was a big rover the size of Curiosity would collect samples, place them in a container the size of a coconut, then just drop the container on the ground on Mars. Another mission would send a second rover to retrieve the container. A third mission would drop an return vehicle capable of carrying the the container to high Earth orbit. It would not return to Earth surface, just high orbit. Then a human mission with an Orion capsule launched on SLS would go and retrieve it. Delta IV Heavy can launch Orion into LEO, but only SLS is big enough to launch it into high orbit. The Orion capsule wouldn't return this sample container to Earth either, it would take it to a new space station in high Earth orbit. Rather than using all the labs on Earth to examine the samples, they would remain in this new space station.

This is a Rube Goldberg machine. Rube Goldberg was a cartoonist in the 1930s, he had a regular cartoon about machines invented by a fictional character named Professor Butt. These machines were ridiculously complicated to do a very simple task. Here's an example from Wikipedia:
Rube_Goldberg%27s_%22Self-Operating_Napkin%22_%28cropped%29.gif

Soup spoon (A) is raised to mouth, pulling string (B) and thereby jerking ladle (C), which throws cracker (D) past toucan (E). Toucan jumps after cracker and perch (F) tilts, upsetting seeds (G) into pail (H). Extra weight in pail pulls cord (I), which opens and ignites lighter (J), setting off skyrocket (K), which causes sickle (L) to cut string (M), allowing pendulum with attached napkin to swing back and forth, thereby wiping chin.

I explained to Dr Zubrin that a scout class mission could send a lander with a return vehicle. Use ISPP to fuel the return vehicle. A small rover about the size of Sojourner would collect samples. The return vehicle would return the sample to Earth the same way Genesis or Stardust did. For those missions, NASA used a helicopter to recover the return capsule. Simple, self-contained. Since that conversation, Dr Zubrin pointed out a mission the size of Curiosity could carry a rover the size of Spirit or Opportunity. This is a lot larger than I proposed, but still self-contained. He's right.

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#98 2019-09-17 09:56:51

Oldfart1939
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Registered: 2016-11-26
Posts: 1,805

Re: Large scale colonization ship

The Politically Incorrect observations here: This mission is made overly complex and unlikely to ever succeed, is so (1) JPL will have a future of designing/building robotics; (2) so that LockMart and Boeing can continue their obscene feeding at the government trough. This drags out the actual journey to Mars by humans to the 2050's. Not to mention the screams of anguish of the Planetary Protection fanatics. NASA has been prevented from sending life finding exploration rovers to areas where life "might still be extant." Then WHY are we sending rovers to places where life probably cannot be found?

Added in edit: The actual search for current life and early life is too important for politics to play such an obscene role. I see the Planetary Protection Lobby activating to prevent SpaceX from doing anything on Mars, as it would corrupt and contaminate the planet; it must be kept in Pristine, and undefiled condition for...________. Fill in the blanks.

Last edited by Oldfart1939 (2019-09-17 10:01:07)

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#99 2019-09-17 12:51:06

GW Johnson
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From: McGregor, Texas USA
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Re: Large scale colonization ship

Look,  there is actually a fairly high likelihood that there is currently life on Mars.  It will be microbial,  and it will be deep underground,  away from the vacuum and the radiation.  I say that because there was very likely once life all over Mars long ago when its climate was more clement.  Life is VERY persistent,  as we already know.

The "proof" of that claim is the purported fossils found inside the Allen Hills ALH84001 meteroite by the two NASA scientists a couple of decades ago.  This has been dismissed generally,  but I think wrongly.  The same kinds of traces in Earth rocks are widely accepted as "proof" of life 3.5-ish billion years ago on Earth.

Life on Mars.  So what?  What difference does that really make for sending men there?  Who will inevitably contaminate the surface with Earthly microbes.  That cannot be helped.  It has already happened on the moon. 

The vacuum and the radiation on Mars (and the moon) will sterilize quite a lot of that,  but not all.  It only becomes an issue of biological warfare when and if we ever terraform Mars (or the moon).  Then the Martian life might try to recolonize the surface,  and find itself in competition with the Earthly contamination microbes.  (I doubt there's any subterranean life on the moon.) 

But then again,  so what?  Life is always in competition with itself.  Even here on Earth. 

The groups wanting to keep Mars "pristine" are not what they seem.  That's a canard to justify not going for any of a plethora of other reasons.  There are all kinds of groups out there with all kinds of agendas.  And,  lying is more common than truth-telling.  Why is anybody surprised by that? 

GW

Last edited by GW Johnson (2019-09-17 12:52:54)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#100 2019-09-17 14:25:59

Oldfart1939
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Registered: 2016-11-26
Posts: 1,805

Re: Large scale colonization ship

To all who care to listen--seems that GW and I are in absolute, complete agreement about life on Mars. I'm actually very curious as to how advanced life may have evolved there; I would love to have the opportunity to split some shale layers looking for some insects--trilobites--primitive fishes and nautiloids. We only have our own time scale of evolution here on this planet; what happened elsewhere is a whole new ballgame.
GW and I also agree on the reasons--the canards being promoted--for NOT GOING!

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