Large scale colonization ship

SpaceNut · 2022-02-21 10:28:16

As noted 1175
We have 2 new topics to discuss propulsion plus 1 older one and what it will take to move the large ship from LEO to Mars mean or initial orbit or Mars low orbit.

Each of these are for limited use and for an exact purpose. Space Tugs are still a chemical engine use but each is different for how it can help move the large ship.

Large Ship Atomic Propulsion

This trades fuel volume for electrical power to move the ship depending on the acceleration rate means an ever increasing power level required. The use of the same system works for deceleration at a high power and larger fuel use initially but can throttle back as the ship does slow but only if you are reaching your insertion velocity to gain orbit on the first try without any aero-breaking in the atmosphere which requires heat shield to perform.

Large Ship Chemical Propulsion

Space tug that uses fuel means we are expending these and dropping there incurred mass of the ship once moving of small or large starship size. The orbital insertion works the same as the in that we are firing up the engines at full power to slow the ships forward velocity but fuel volume is the limiting factor for both given how much we are trying to push or slow.

Nuclear Pulse Propulsion starship
The size of bomb blast against the pusher plate is how we accelerate and similarly how we would slow down.

Its a balancing equation for all three cases of how we move the mass of a large ship.

SpaceNut · 2022-02-23 20:58:42

The water wall mass is for a bagged section that is the width of the hull 19 meters and for the outside circumference of 238 meter that is 10 cm. that is hidden under the floor of about 452,200 kgs of water.

The fact that we would want a water wall on the other 3 locations of the ring means we carry a large mass for the large ship.

The decks are 2.4 m so that is going to be about 5 meters to the inside circumference. That makes for a water wall of 110,400 kgs for each side of that.

The inner circumference is 205.083 meters so at a width of 19 meters the 10 cm filled bag is going to be 389,500 kgs.

I am assuming that each is not a continuous one size covers all but is made up of many segments to accomplish the task of providing shielding for the crew inside the hull of the ring.

So total water needed for the walls is
452,200
110,400
110,400
+ 389,500
----------
1062,500 kgs or 1063 mT of water for shielding

tahanson43206 · 2022-02-23 21:19:57

Google found a Ferris wheel that is described as 80 meters in diameter...

https://access.openupresources.org/curr … index.html
Here is a picture of a Ferris wheel. It has a diameter of 80 meters.
https://access.openupresources.org/curr … age.04.png
“Steiger Ferris Wheel 1102009 1” by Zonk43 via Wikimedia Commons. Public Domain.

(th)

RobertDyck · 2022-02-24 02:02:54

Math:
Area is Pi x R², or using the limited font available here, πR². Radius is 37.6992 metres. That last digit is 2/10 of a millimetre; I calculated that precisely because Mars gravity is given to 6 significant figures. This means the area of the circle is 3.14159 x (37.6992)² = 4464.92472, there are more digits that I saved in calculator memory. But the circle isn't solid, it's a ring. Ceiling is 2.43m high, so area that isn't water wall is 3.14159 x (37.6992 - 2.43)² = 3907.8788, again more digits on my calculator. Subtract that from the first area and you get 557.0458842 m². Then multiply by 0.12, because an article by Robert Zubrin suggested 12cm thickness instead of 10cm. Result is 66.8455 m³. Mass of water is 1 gram per cubic centimetre. There are 100 x 100 x 100 = 1,000,000 cubic centimetres per cubic metre. There are 1,000 grams per kilogram, and 1,000 kilograms per metric tonne, so 1 m³ of water masses 1 metric tonne. So that means there is 66.8455 tonnes or 66,845.5 kg of water in the water wall.

There is no water "under the floor". The water wall is shadow shielding. That means the water wall must be carefully oriented toward the Sun so the entire width of that one deck is in the shadow of the water wall. Also note: the upper deck is not shielded, so must be off limits during a Solar Proton Event. The upper deck has 2 observation rooms, Mars simulation room, greenhouses, fish tank, and advanced life support including processing concentrated urine to extract salt, baking soda, grow microbes in a vat to produce oil, process starch into sugar, etc.

We could calculate how much water is in the hydroponic system, and how much in the fish tank. And how much in the vat that grows mould to produce amylase enzyme. And how much in the vat that uses that enzyme to break down starch into sugar. And how much in the vat that grows microbes for oil. These figures are significant, but I don't have those numbers.

SpaceNut · 2022-02-25 20:59:12

We are covering only 1 surface out of 4?

That means the solar panels are 45' towards the sun and the sun will blast any surface that is not blocked with radiation by how the ship is angled such that the opposite sides inner ceiling wall will be partially lit up. Solar power will drop in half as a result of that angle as well.

RobertDyck · 2022-02-25 22:21:24

This is why we've spoken a lot about the need to orient the ship. The aft end must be precisely aligned with the Sun, not angled at all. The axis of rotation is a line perfectly pointed to the Sun. So as the ship rotates, the aft end is always perfectly toward the Sun. Yes, that means the bow is not pointed in the direction of travel, but when ship is coasting does it matter?

If the bladder of the water wall extends down to the hull, but hull isogrid stiffener depth is 0.5" (12.7mm), and flooring thickness is 1/2" (12.7mm). That means the water wall extends 25.4mm below the walking surface. Over 19 metres that allows an angle of 0.0766° without exposing passengers to radiation.

With the aft side of the face of the ring perfectly perpendicular to the Sun, that provides full Sun so full solar power.

SpaceNut · 2022-02-26 11:29:27

That makes the max solar panel around that sun facing side only 557.0458842 m² less the slices between 1 m square panels far less for power to be generated from continuous kWhr to use. So that is just part of the power issues and when you add in the field density that is huge to get 20 Tesla field values ( quaora given ) mean the only way to power this is a nuclear reactor in the core hub.

posting in that topic

RobertDyck · 2022-02-26 12:10:35

Price comparison: British Airways, 777-200 4-class layout
Economy - pitch 31", width 17.5" = area 542.5
Premium Economy - pitch 38", width 18.5" = area 703
Business - pitch 72", width 20" = area 1440
First - pitch 78", width 22" = area 1716

British Airways, A350-1000
Economy - pitch 31", width 17.6" = area 545.6
Premium Economy - pitch 38", width 18.7" = area 710.6
First - pitch 79", width 27" (closed suite) = area 2133

Pitch is distance from a given point on a seat to the same point on a seat in the next row. Area is square inches.

Ticket price directly from British Airways website, as of today. Flight from London to New York, one way, one person, March 12 (2 weeks from now), Boeing 777.
Economy £1,781 = 3.283 / sq.in.
Premium Economy £2,023 = 2.877667 / sq.in.
Business £7,124 = 4.947 / sq.in.
First £9,509 = 5.54 / sq.in.

For our ship, I suggested a constant price per cabin regardless of furniture or how many passengers. Premium cabins would be based on floor area. Should we increase the price of premium cabins? The only perk I suggested for premium cabins is meals in fine dining room and booze at the bar would be free (included), while they would cost for other passengers.

::Edit:: I should be consistent. I should use the word "luxury" because one of the cabin layouts is called "Premium".

Last edited by RobertDyck (2022-02-26 13:12:15)

SpaceNut · 2022-02-26 12:19:07

I was basing the central hub from an approximate 20 starships low end mass of 85 mT, for fuel tank requirements, we are most likely close for that central Hub mass of 1700 mT.

RobertDyck · 2022-02-26 17:20:49

I don't see how you got 20 Starship masses for the hub.

Central hub will be 9 metres diameter, same as SpaceX Starship. The hub will be 22.86m (75 feet, same as SpaceX Starship payload length to tip of nose, but this will be cylinder the whole length). Zero-G cargo hold: 9m diameter x 22.86m length, and that's aft of the hub, in addition to the hub. A simple pressure bulkhead will separate the hub from cargo hold, with pressure hatch. The hull of the hub and zero hold will be similar to the hub elsewhere: inner pressure hull, multi-layer insulation, and micrometeoroid shield. Inside surface of the hub will be covered in gymnastic mats. This is to protect the hull as well as allow individuals who play in the zero-G hub to avoid injury. Forward end of the hub will have an airlock. The forward end of the airlock will be a docking hatch. This docking hatch will allow a SpaceX Starship to dock. It will require a hatch larger than APAS or NDS.

NASA Docking System (NDS) is NASA's implementation of the International Docking System Standard (IDSS). Precursor was the International Low Impact Docking System (ILIDS). It's based on APAS, which was designed to allow a 125 metric tonne Space Shuttle to safely dock with a 300 metric tonne Space Station. NDS is designed to allow a 13 tonne Starliner or 8 to 11.49 tonne Dragon to dock. NDS has a hatch diameter for cargo transfer the same as APAS: 800 mm (31"). That isn't enough for significant cargo. Common Berthing System (CBM) has a square hatch with rounded corners, 1.3 metres (50") wide. More reasonable for a large ship, but CBM has no shock absorbers, a ship cannot dock without aid of the station's robot arm. A new hatch will be required for the large ship, with matching hatch for Starship. An adapter will be mounted on an arm with a simple hinge to move the adapter out of the way. The adapter will provide a pressure seal to the large docking hatch, the other side will be an NDS hatch. This will allow Dragon or Starship or other spacecraft to dock.

Aft of the cargo hold will be control moment gyros. These will have to be large for a ship with this mass. The gyros will be in an area not pressurized, and the frame holding the gyros will have to be de-spun, the only part of the ship that will be de-spun.

Aft of the gyros will be the propulsion module. Hull around the gyros will be attached to the cargo hold, and spun at the same rate. The propulsion module will be attached in such a way that it can be removed and replaced. But the propulsion module will attach to the hull around the gyros that is firmly attached to the cargo hold. So the propulsion module will rotate at the same rate as the rest of the ship. This provides a firm attachment.

tahanson43206 · 2022-02-26 17:55:45

For RobertDyck ... thanks for providing the detailed information in Post #1185

Please consider placing a copy of that post in the Engineering topic.

** Real ** engineers (not already in the membership) attempting to understand your ideas will find it useful.

(th)

SpaceNut · 2022-02-26 19:01:18

I think that if all were equally loaded one could calculate the mass distribution by volume of each area though its a rough approximate.

ring circle is 3.14159 x (37.6992)²= 4464.92472/ 6,463 = 69% x 5000 = 3450 mT
3 tunnels is 37.6992 - 2.43 - 4.5 = 30.7692 x 2.43 x 2.43 = 181.6890 x3 = 545.0671/ 6,463 = 8.5% x 5000 = 425 mT
hub 9m diameter x 22.86m length = 1454.29036 / 6,463 = 22.5% x 5000 = 1125 mt

edit
If one uses a starship size and mass we can get a rough estimate of the hull and empty people tank aka habitable area.
The section of one is about 40m to where its starting to curve and I would estimate the mass as being 60 mT for the 9 m Diameter.

Ring hull is approximate 240 m is close to the actual circumference of the ring. that the (19m + 2.34m ) x2 = 42.68 m with a starship being 3.141 x 9m = 28.268 m. So even if we use 2 for each section we have a buffer for the over estimate when 6 x2 x 40mT = 480 mt for the ring hull mass empty.

tunnels we can us 3 of them for 120 mt for the spokes which would cover the features and then some.

center hub if main engines are in space tug means just 1 unit mass or 160 mT would be needed.

So materials for a solid stainless steel with inner hull plus.
480 mT
120 mT
+160 mT
--------
760 mT

So we have lots of margin in a 5000 mT ship to get smaller in Mass.

RobertDyck · 2022-02-26 19:49:57

I think the large hatch should be round. Because the ship will be rotating as Starship approaches to dock. Orienting rotation should not be a concern.

SpaceNut · 2022-02-28 20:47:44

Looks like a plasma mini megosphere is possible for the aerocapture for mars but do not feel that we can for earth.

kbd512 · 2022-02-28 23:39:31

Robert,

It looks like Vascomax sells C250 maraging steel plates, measuring 12mm by 1000mm by 2000mm, for $55.65USD per square meter. If your large ship had a surface area of 20,000m^2 and was made from 12mm thick plates machined into isogrid structures, similar to the Aluminum "potato chips" that ULA carves into isogrid plates to fabricate Atlas V propellant tanks, then you're looking at $1,113,000USD in terms of materials. This material comes from India.

C250 has a YS of 250ksi, UTS of 255ksi, and requires heat treatment at 900F to achieve those properties. 304L stainless, which also has excellent weldability like C250, has a YS of 25ksi and UTS of 70ksi. The same company sells 304L for $2/kg or $2,000/t, whereas C250 is $577.52/t. In terms of yield strength (YS), you have approximately 10X the strength for about 3.5X less cost. Once the structure yields, failure will likely progress until it completes, so ultimate tensile strength (UTS) figures are only interesting from the standpoint of understanding when a total failure will occur. 316L, which is even more expensive has a 30ksi YS. What this really means is that you can use much thinner and therefore lighter maraging steel structures, as compared to 304L. Within its temperature limits, maraging steel is extremely tough and strong, unlike any stainless that isn't also very brittle. The primary advantage is no Chromium at all. It's also corrosion resistant, but not a true stainless, so polishing or surface treatment will be necessary to inhibit corrosion. This material could be painted, ceramic coated, powder coated, or a Nickel-based finish applied. The Nickel finish would be pretty durable and shiny / slick. The powder and ceramic coatings require heat. White Titanium-based paint would be cheapest and probably easiest to remove, although it would burn in a fire. C250 is semi-magnetic, unfortunately, unlike non-magnetic stainless.

You need a lot of steel plate, it needs to be cheap / ductile / easy to machine and weld / resistant to impacts / dimensionally stable, so C250 fits the bill. You may also get away with even cheaper materials with appropriate surface treatments, but they won't be nearly as strong and will be strongly magnetic (may or may not be an issue for the EM shield).

My advice would be to use the 304L for cryogen tanks only, prevent the C250 from getting too cold, and you get a very tough and durable steel that is easy to repair by welding. Machine the potato chips here on Earth, roll them, heat treat them, then weld them together in orbit using EBW.

tahanson43206 · 2022-03-01 07:56:25

For kbd512 re 1190

Because RobertDyck just created a new topic dedicated to hull design, I put a copy of your post #1190 over there.

Question for you .... Because RobertDyck will be presenting via Zoom on March 12th, is there any chance you might be available to serve as a backup for Questions at the restaurant? I ask because it is difficult for a Zoom presenter to hear the onsite questions, and you are as familiar as anyone with what RobertDyck is trying to do.

It would ** also ** be an opportunity for you to make a pitch to give a talk on your counter-rotating design in May.

May would give you plenty of time to make progress in developing your concept.

I am hoping you will develop an interest in working with Blender ... I don't know if you can afford to add a computer to your family environment, but if you can, and if one of your kids is interested in learning computer animation, Blender is just about the best free package there is.

I have some (modest) experience with Blender (as reported at length in the forum) and RobertDyck has demonstrated his ability to create high quality renders of Large Ship.

(th)

SpaceNut · 2022-03-01 18:46:43

RobertDyck
The flooring of a submarine uses a cement cover on top of the deck steel inside the pressure hull to sound obsorb but to give a ridgid strength that is just a 1/4" thick.

We could use a flooring wood grain simulation that sells with a tongue and groove assembly feature that is plastic.
Flex Flor® Loose Lay Vinyl Planks Embossed for a genuine hard-wood floor appearance No adhesive needed, simply lay it down and done 1 box includes 4 vinyl embossed planks and covers 12 sq ft Each plank is 9" x 48" / 3 sq ft (22.86cmx 121.92cm / 5.0mm thick)

230701_2020_LaminatFlooring_Internet__L_Web.jpg&height=475&width=475

tahanson43206 · 2022-03-01 21:54:48

For SpaceNut re stick-on flooring ... Post #1192

This suggestion seems (to me) like a good fit for the cabins. The hull itself (as GW Johnson keeps reminding us) should have NOTHING at all on the surface of the hull that is inside the vessel, so it can be quickly repaired.

RobertDyck recently showed the ISS practice, which is interesting but not applicable. The ISS practice is to cover every bit of the interior of the habitat with cabinets that can be pulled back from the hull in case of a leak.

The situation is dramatically different in Large Ship ...

RobertDyck recently clarified that the exterior surface of the hull would be protected. I am working from memory so will encourage forum readers to find recent posts by RobertDyck for details.

However, GW Johnson is recommending that all interior hull surfaces should be free of objects.

There is NO need for objects to be on the interior of the hull surface.

The floor of the habitat should be a couple of meters ABOVE the hull surface.

I'm not sure where RobertDyck came down on that point, but I'm hoping he is willing to give GW Johnson's suggestion some consideration.

The diameter of the deck where passengers will be walking is 75 meters.

The diameter of the ship itself can be as much larger as is needed to accommodate all the systems that will be needed for thermal and radiation protection.

(th)

RobertDyck · 2022-03-01 23:13:47

tahanson43206 wrote:

RobertDyck recently showed the ISS practice, which is interesting but not applicable. The ISS practice is to cover every bit of the interior of the habitat with cabinets that can be pulled back from the hull in case of a leak.
The situation is dramatically different in Large Ship ...
RobertDyck recently clarified that the exterior surface of the hull would be protected. I am working from memory so will encourage forum readers to find recent posts by RobertDyck for details.

I'm suggesting flooring should protect the isogrid of the hull. However, flooring should be designed so it can be pulled up quickly to check for a leak.

tahanson43206 wrote:

However, GW Johnson is recommending that all interior hull surfaces should be free of objects.
There is NO need for objects to be on the interior of the hull surface.
The floor of the habitat should be a couple of meters ABOVE the hull surface.

This ship will have limited space. It's large, but space per person is not that great. Economy cabins have the same space per person as a 3rd class cabin in the age of steam ships. But you can't waste space. Flooring will laid on the risers of the isogrid of the hull, attached at intersections of the risers.

Side walls of the ring are end walls for cabins. Bunk beds will be pushed against the side walls of the cabin (bulkheads), and pushed into the corner so the head of the bed is against the end wall. That means for outside cabins, they're against the hull. Forward cabins have a porthole window that looks into deep space, away from the Sun. Night tables (night stand tables) will be attached to the wall to ensure drawers under the bed can be opened freely. Night tables cannot extend to the floor. Yup, that means night tables attached to the hull.

The aft end of the habitation ring will be Sun-ward. That's the wall facing the Sun, so that's where the water wall goes. There will be a composite wall that acts as the cabin end wall, and that will also have attachment points for night tables. Between the composite wall and the hull will be the water bladder. So that part of the hull will be completely covered.

tahanson43206 wrote:

The diameter of the deck where passengers will be walking is 75 meters.

Radius from centre of rotation to surface of the floor of the habitation ring: 37.6992 metres
Diameter of the deck where passengers will be walking is twice radius: 75.3984 metres
Circumference is Pi x diameter: 236.871 metres

RobertDyck · 2022-03-01 23:29:12

For those concerned with aerocapture, here is a clip that I mentioned. The movie "2010: The Year We Made Contact" is the sequel to "2001: A Space Odyssey". That movie is sometimes called "2010: Odyssey Two". It was made in 1984, so it shows Soviet astronauts wearing uniforms with the Soviet flag and "CCCP". The ship with the rotating section is supposed to be Soviet built. This scene shows aerocapture into Jupiter orbit. Jupiter is a much bigger planet, with much more gravity, and much thicker atmosphere. This scene portrays use of a multi-section balloot. That's an inflatable heat shield (word based on "balloon"). Notice the American astronaut sits on a bed with his back to the forward wall. As the ship is breaking, he is pushed into that wall. Notice a picture falls onto that wall. When breaking stops, the picture falls. However, although there is significant deceleration, he remains seated on the bed.

Unfortunately this clip is in Spanish. YouTube: 2010: Odyssey Two - Braking Maneuver

tahanson43206 · 2022-03-03 12:37:53

For RobertDyck re #1195

Thank you for the entertaining reminder of a fictional depiction of a flight to Jupiter.

The balloot does not exist of course. I'm sure you were not intending to imply that it does exist. And (of course) the atmosphere of Jupiter is massive and capacious, and it could handle anything thrown at it.

For a realistic look at what will happen to Large Ship if it has the misfortune to enter an atmosphere, we have a 10,000 metric ton asteroid as a recent example.

Google found this set of snippets:

"The asteroid was about 17 meters [56 feet] in diameter and weighed approximately 10,000 metric tons [11,000 tons]," Peter Brown, a physics professor at Western University in Ontario, Canada, said in a statement.
Jan 9, 2019
Chelyabinsk Meteor: A Wake-Up Call for Earth | Space
www.space.com › 33623-chelyabinsk-meteor-wake-up-call-for-earth
About Featured Snippets
Chelyabinsk meteor - Wikipedia
en.wikipedia.org › wiki › Chelyabinsk_meteor
The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural region in Russia on 15 February 2013 at ... With an estimated initial mass of about 12,000–13,000 tonnes ...
Chelyabinsk meteorite · Tunguska event · Bolide · 367943 Duende

There are numerous videos of the event available for anyone to use to understand what will happen to Large Ship if it gets anywhere near an atmosphere.

4:30
Meteor Strikes Russia, Over 1,000 Believed Injured - YouTube
https://www.youtube.com/watch?v=gRrdSwhQhY0
Meteor Hits Russia Feb 15, 2013 - Event Archive - YouTube
www.youtube.com › watch
Feb 18, 2013 · The blast, equivalent to 300,000 tons of TNT, shattered windows, damaged more than 3,000 ...
Duration: 10:12
Posted: Feb 18, 2013

If a human being is responsible for placing 1060 people in that situation, the families of each and every one of them will be entitled to damages.

(th)

RobertDyck · 2022-03-03 15:55:47

NASA does have an inflatable heat shield, called HIAD (Hypersonic Inflatable Aerodynamic Decelerator). The next test is scheduled for this year: Inflatable Heat Shield One Step Closer to 2022 Demonstration

SpaceNut · 2022-03-03 19:58:13

Not sure that the inflatable in the wrap around would work but we do know that we have others that will

Sure an over sized pica shield would make the ship look like a mushroom
https://www.designworldonline.com/reduc … at-shield/

P1190055.resize-1920x1440.jpg

under side attachment

update to central construction mass number. GW gave the fuel loading as .97 for ration and that means we need 150 mT of fuel onboard for cruise to course corrections and breaking to settle into orbit in addition to the shield materials design of Adapt or other.
To support that we need to bump the central mass by 20 mT and add to its length around 20 meters at the 9 m diameter.

So the new numbers for the ring hull is 480 mT
The spokes and tunnels remain unchanged 120 mT
while the central hub is going up from 160 mT to 180 mt less fuel load of 150 mT

Water wall 67 mT

That brings the known mass allotment of 5000mT down 3903 mt to fill the ship with everything else that we need.

Now to start looking at the food, water, air mass bulk and then what is required for recycling equipment and mass shift as well as power load changes with it.

one of the topics to draw information from Air. Shelter. Water. Food of which I am sure we have others.

GW Johnson · 2022-03-04 13:09:56

Y'all have SERIOUSLY misunderstood what the R = 0.97 applies to.

It is the ratio of propellant in the propulsion stage to the total mass of JUST the propulsion stage WITHOUT the dead-head payload! It is simply a way to estimate stage inert mass from a guess for stage propellant mass.

You have to add the stage inert (a few hundred tons) to the dead-head payload, to get the burnout mass for the rocket equation. Then you add your propellant mass to that, to find the ignition mass for the rocket equation. It is inherently and inescapably a REALLY HUGE propulsion stage! There is simply no way around that ugly little fact of life.

This calculation process is INHERENTLY iterative: you estimate the delivered dV from the rocket equation and compare that to the summed, factored astronomical dV's which that weight statement is supposed to cover (departure, course correction, arrival). You iterate your guesses for propellant mass until the delivered and the required dV's converge. That's what the spreadsheet is for!

Robert's ship is my dead-head payload, and it has a mass that we don't yet know. Period. I've been using 5000 tons as a "ballpark figure".

It takes 21,110 metric tons of propellant IN ORBIT AT EARTH to send 5000 metric tons of dead-head payload from LEO to LMO, ONE WAY at LOX-LCH4 Isp = 380 s in vacuum. It takes another 21,110 tons of propellant IN ORBIT AT MARS to send that same 5000 tons from LMO back to LEO.

All else being equal, it will take 21,110/5000 = 4.222 tons of propellant per ton of dead-head payload (whatever that really is) to make the one-way trip from LEO to LMO, by min-energy Hohmann transfer. You need another 4.222 tons per ton of dead-head to return from LMO to LEO. That's some 8.444 tons per ton dead head for the round trip, half in orbit at Earth, the other half in orbit at Mars! If you fly faster, those numbers are higher. Period!

There is just no way around those dauntingly-high numbers with any sort of chemical propulsion, and it is almost as bad with solid core nuclear, because your Isp improvement is only about a factor of 2. THAT is the tyranny of the rocket equation.

GW

Last edited by GW Johnson (2022-03-04 13:19:08)

kbd512 · 2022-03-04 13:57:48

GW,

I presume the numbers associated with this analysis could then be used, roughly speaking, for higher-Isp propulsion options, provided that they still allow for impulsive transfers.

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