Mars Colonial Transporter

Oldfart1939 · 2017-02-05 10:37:59

Just another WAG from me--once Elon gets into the engineering and hardware stages, some things will change. We've all seen the optimism that drives him become moderated over time. Falcon Heavy has slipped time after time, and maybe this year we'll see a launch. Now scheduled for April, followed by several (2 at this juncture) commercial payloads later in the year. We may also see the launch of the Man-Rated Dragon 2 later this year and the abort test. These are all critical steps, moving forward.

SpaceNut · 2017-02-05 20:25:13

Lets work it from what we know from the Falcon 9 heavy rocket which can place reuseble rocket first stages a payload to LEO of 54.4 tonnes, compared to 22.8 tonnes for a Falcon 9 full thrust using the same second stage for both.
So basically its 10 heavy rockets tied together to form this new monster.....That is 30 first stages and 10 upper stages....now to go find dry and wet mass for each.....

Falcon 9
Height 70m 229.6 ft Mass 549,054 kg 1,207,920 lb

Dragon Height With Trunk 7.2m 23.6 ft Diameter 3.7m 12 ft

Falcon 9 heavy
Total Width 12.2m 39.9 ft Mass 1,420,788 kg 3,125,735 lb

First stage calculated mass 435,867 kg
Second stage calculated mass 113,187 kg

Payload to LEO 22,800 kg 50,265 lb

Dragon capsule Dry mass 4,200 kg (9,300 lb)
capsule can transport 3,310 kg (7,300 lb) of cargo

MCT :

Since the second-stage-plus-spaceship will have used its fuel in getting to orbit, it would need to refuel in orbit, filling up with about 1,950 tons of propellant (which means that each launch carrying passengers would require four additional launches to deliver the necessary propellant).

SpaceNut · 2017-02-06 18:18:15

http://spaceflight101.com/spacerockets/ … -v1-1-f9r/

Falcon 9 v1.1 Total Launch Mass >505,846kg (F9R)
Falcon 9 v1.1 Stage 1 Inert Mass ~23,100kg (F9R: ~25,600kg)
Propellant Mass 395,700kg LOX Mass 276,600kg RP-1 Mass 119,100kg

Falcon 9 v1.1 Stage 2 Inert Mass 3,900kg
Propellant Mass 92,670kg LOX Mass 64,820kg RP-1 Mass 27,850kg

Payload Fairing Composite Fairing
Diameter    5.2m
Length    13.1m
Weight    ~1,750kg

Mass to LEO 13,150kg

RobS · 2017-02-06 18:31:54

But that's not the current version of the Falcon-9, which is the Falcon-9FT or "full thrust." It can lift 21,000 kg to LEO with an expendable first stage. It will be replaced later this year by the "Falcon-9 Bloc 5" which will have even more thrust, reinforced landing legs, and other changes to make the first stage more reusable. The Wikipedia article has the details.

They haven't said anything more about the Falcon Heavy's lift capacity, but with 3 Bloc-5s, it must be more than 54 tonnes. If they were to build a bigger second stage, also, they could probably push it up pretty close to 70 tonnes.

SpaceNut · 2017-02-06 18:37:53

https://en.wikipedia.org/wiki/SpaceX_re … nt_program

The total span of the four carbon fiber/aluminum extensible landing legs is approximately 18 meters (60 ft), and weigh less than 2,100 kilograms (4,600 lb). Deployment system uses high-pressure Helium as the working fluid.

http://space.stackexchange.com/question … irst-stage

They have said that they will reserve around 15% of the fuel capacity of a first stage for reusability operations. At the point they need to impart the Delta-V to return to base, they will thus be 85% empty.

SpaceNut · 2017-02-06 19:38:51

https://en.wikipedia.org/wiki/Falcon_9_Full_Thrust
Yes more payload at the sacrifice of the first stage, and re-engineering of the engines to get more power out of them....still its the same amount of fuel its just not used to return the stage back to earth but is used to put the payload into orbit instead.

It's about a 30% increase in performance, maybe a little more for that 15 % of fuel used for returning the stage normally. Only it will cost you more for its use...

Oldfart1939 · 2017-02-06 21:23:37

A much more powerful 2nd stage is within the realm of possibility; if they experiment with a new Raptor engine replacing the Merlin 1-D+, the numbers I've seen figures stating triple the thrust and an increase in Isp(vac) to 383 Seconds. This could be what Musk has in mind for the Red Dragon mission to Mars?

RobS · 2017-02-06 21:26:08

The Red Dragon they're scheduled to launch next year will use a regular Falcon Heavy.

3015 · 2017-02-07 02:11:08

RobS, There are several on the SpaceX forum on reddit who argue the figures on the website are for Block 5 rather than the current version, so 54t may well be the ultimate payload capacity of the falcon heavy.

RobS · 2017-02-07 06:22:09

Oh, that's interesting. Thanks for letting me know.

Quaoar · 2017-03-10 05:23:51

Oldfart1939 wrote:

The stoichiometric ratio of O2 and CH4 is a ratio of 64 to 16 in mass. CH4 + 2 O2 ----> CO2 + 2 H2O. If less oxygen is used there will be carbon monoxide formed, CO. There is also as a consequence, some deposition of carbon, or coking. I haven't seen the fuel/oxidizer ratio for either RP-1 or CH4 in the Merlin 1D+ engine versus the new Raptor.

the F/O ratio of the Raptor engine, according to Wikipedia, is 3.8: very close to the stoichiometric ratio.

https://en.wikipedia.org/wiki/Raptor_(r … ne_family)

Last edited by Quaoar (2017-03-10 05:24:50)

elderflower · 2017-03-10 05:47:08

I saw a report of tests (don't ask me where) that with RP1 15% of the carbon would go to CO and the balance to CO2. Coking wasn't mentioned. I am trying to remember some more of this, but that 15% figure stuck in my head.

RobS · 2017-03-10 07:46:02

Zubrin in the Case for Mars sais that the methane / oxygen ratio of the Mars vehicles would be 3.5 to 1 because the mean molecular weight of the exhaust gas is less (CO weighs less than CO2) and that increases exhaust velocity, even though the combustion is incomplete. Hydrogen/oxygen engines apparently burn at 6:1 O to H even though the stoichiometric ratio should be 8:1.

elderflower · 2017-04-19 14:18:44

Just looking at the diagram in Spacenut's post (#37).
There doesn't seem any way I can derive the saving in delta V due to manoeuvres past Venus or Moon en route to Mars. We only need the four to six month direct transfers to Mars for human or human dependent missions. For positioning cargo or orbiting facilities transfer duration is likely to be less important. So if we can save any dV we can ship more payload mass per shot.
Can anyone enlighten me as to the potential impact on cargo delivered, of flyby manoeuvres?

RobS · 2017-04-19 15:26:18

It takes slightly less delta-v to get to Venus than Mars, and if Venus does the rest of the work, there should be an increase in cargo mass if sent via Venus, but at the expense of a longer transit time (about 300 days, I think).

Oldfart1939 · 2017-04-19 15:58:12

The minimum delta V for a Hohmann transfer is 3.4 km/second. That results in a 250 day transit time to Mars. Most of the manned transit flights should aim for a delta V between 3.6 and 4.0 km/second, which results in a 180 day mission (best case). The Rocket equation is a demanding master, but the longer time does give a substantial payload increase over and above the minimum transit time trajectory.

louis · 2017-04-20 03:31:23

A six month journey in zero G gives bone loss of on average about 10%. One hopes this can be ameliorated during the Mars surface stay (this can be tested experimentally on the moon to some degree with weighted suits). Space medicine is also going to be helpful:

https://www.nasa.gov/mission_pages/stat … _loss.html

Oldfart1939 wrote:

The minimum delta V for a Hohmann transfer is 3.4 km/second. That results in a 250 day transit time to Mars. Most of the manned transit flights should aim for a delta V between 3.6 and 4.0 km/second, which results in a 180 day mission (best case). The Rocket equation is a demanding master, but the longer time does give a substantial payload increase over and above the minimum transit time trajectory.

elderflower · 2017-04-20 09:36:11

It could be totally ameliorated using artificial g in a rotating vehicle. I am completely in agreement with GW on this. For the penalty of some reaction wheels we get a much better chance of delivering, and more importantly returning, a fit crew. We don't need to add risk to a Mars mission.

louis · 2017-04-20 09:54:28

Well I feel it's a distraction. We can choose astronauts who have low bone loss. Valery Polyakov lost only 7% bone mass while in zero G for 14 months. On a six month voyage to Mars he would have lost only 3% (and that's without the more advanced space medicine now becoming available). It's the load bearing bones that lose mass, proving it will be regained on Mars as long as we ensure they wear weighted suits and exercise regularly.

Polyakov would probably have recovered 2% whilst on Mars - so overall loss by return to Earth would be around 4%.

Has anyone actually spent 6 months in a centrifuge? I suspect not, in which case we will have to go through a whole testing regime to establish what the effects are.

elderflower wrote:

It could be totally ameliorated using artificial g in a rotating vehicle. I am completely in agreement with GW on this. For the penalty of some reaction wheels we get a much better chance of delivering, and more importantly returning, a fit crew. We don't need to add risk to a Mars mission.

Last edited by louis (2017-04-20 09:55:48)

Oldfart1939 · 2017-04-20 10:17:08

Louis-

The provision of some artificial gravity is undoubtedly helpful, but there are potentially some medical treatments available. I'm currently attempting to find a research partnership for a NASA SBIR grant to try some hormonal experiments that could reduce bone loss. The #1 drug for treatment of Osteoporosis is a polypeptide hormone, Calcitonin. This hormone stimulates Calcium uptake. Another peptide hormone, Amylin, slows the action of Osteoclasts, the cellular mechanism of bone loss. I'm hoping to find a University researcher with a similar interest in looking into a set of mouse/rat/Guinea pig experiments on the ISS. A serious investigation of the mechanism of bone decalcification in microgravity conditions is very important.

P.S. I was working on writing a similar proposal 12 years ago, but there was no funding available, nor did there seem to be any interest.

Last edited by Oldfart1939 (2017-04-20 10:19:24)

SpaceNut · 2017-04-20 17:18:52

Which brings me to the food that will be brought as to what will be preloaded to the selected landing site for future use.
Food for Mars It’s a daunting challenge, NASA says. NASA’s goal is the development of foods that will remain both safe and appetizing for at least five years.

Canned goods have a good shelf life, but can’t be heated in microwaves — and are considerably heavier than the pouches that astronaut food is dispensed in today. And weight is a big issue. It constitutes about 15 percent of the payload of food, which is expected to weigh 9,660 kilograms (10.6 U.S. tons) for a crew of 6 heading out to Mars.

12818

BEYOND ITS 'SELL DATE' Mars-bound astronauts may have more stomach complaints than space sickness: servings of apples from a pouch packaged recently and sterilized with pressure-assisted technology (left) and from one 2 years ago (right) show the older serving doesn't pass muster.

12819

AGED TO MUSHINESS Although the 2-year-old pears (right) retain the color of newly packaged ones (left), the prolonged storage left them unpleasantly mushy.

So if you are expecting to eat like an Earthly king you are probably going to starve is you think that the color is wrong on that the consistancy is any less than solid.....

Foods destined for space shuttle missions must have a shelf life of a year, and 18 months if they’ll be deployed on the International Space Station. Of the roughly 65 foods currently available for stocking spacecraft and deemed really palatable by NASA taste panels, 10 will lose their appeal within a year — turning off-color, mushy or tasteless, she reported. By the end of five years, Perchonok says, “we’re down to seven items.”
Moreover, she adds, “studies have shown that if the acceptability or the sensory properties degrade, so does the [food’s] nutrition.” Indeed, after one year, space food exhibits notable losses of vitamin A, folic acid (an important B vitamin) and thiamine (another B vitamin that plays a role in the body’s use of carbs and certain building blocks of proteins). And nutrient losses don’t end there, Perchonok says. “Basically, after one year, we are out of vitamin C.”

So if you are eating poorly then all the vitimans will not help.....

louis · 2017-04-20 17:47:47

This for me this is a good example of NASA wasting a load of money on unnecessary research. If people will only go to Mars on condition they receive cordon bleu meals then they really shouldn't be going. Loads of foods last well if stored properly.

https://www.usaemergencysupply.com/info … oods#link7

For many months on the flight out, the crew can enjoy lots of fresh food: fruit and so on. This will probably extend into their stay on Mars.

Once on Mars they can grow a range of salad vegetables.

Otherwise there is no reason why they shouldn't rely on a range of canned, frozen, vaccuum packed and dried foods. Chocolate lasts well, especially if kept chilled. They can enjoy those on the return flight. Shouldn't NASA be diverting this expenditure to ISRU projects.

SpaceNut wrote:

Which brings me to the food that will be brought as to what will be preloaded to the selected landing site for future use.
Food for Mars It’s a daunting challenge, NASA says. NASA’s goal is the development of foods that will remain both safe and appetizing for at least five years.
Canned goods have a good shelf life, but can’t be heated in microwaves — and are considerably heavier than the pouches that astronaut food is dispensed in today. And weight is a big issue. It constitutes about 15 percent of the payload of food, which is expected to weigh 9,660 kilograms (10.6 U.S. tons) for a crew of 6 heading out to Mars.
https://www.sciencenews.org/sites/default/files/12818
BEYOND ITS 'SELL DATE' Mars-bound astronauts may have more stomach complaints than space sickness: servings of apples from a pouch packaged recently and sterilized with pressure-assisted technology (left) and from one 2 years ago (right) show the older serving doesn't pass muster.
https://www.sciencenews.org/sites/default/files/12819
AGED TO MUSHINESS Although the 2-year-old pears (right) retain the color of newly packaged ones (left), the prolonged storage left them unpleasantly mushy.
So if you are expecting to eat like an Earthly king you are probably going to starve is you think that the color is wrong on that the consistancy is any less than solid.....
Foods destined for space shuttle missions must have a shelf life of a year, and 18 months if they’ll be deployed on the International Space Station. Of the roughly 65 foods currently available for stocking spacecraft and deemed really palatable by NASA taste panels, 10 will lose their appeal within a year — turning off-color, mushy or tasteless, she reported. By the end of five years, Perchonok says, “we’re down to seven items.”
Moreover, she adds, “studies have shown that if the acceptability or the sensory properties degrade, so does the [food’s] nutrition.” Indeed, after one year, space food exhibits notable losses of vitamin A, folic acid (an important B vitamin) and thiamine (another B vitamin that plays a role in the body’s use of carbs and certain building blocks of proteins). And nutrient losses don’t end there, Perchonok says. “Basically, after one year, we are out of vitamin C.”
So if you are eating poorly then all the vitimans will not help.....

SpaceNut · 2017-04-20 18:20:29

When you start talking about a canned item you now are putting in water, the container materials mass and that will be quite heavy. The above option in first quote box was at 15% of the weigh 9,660 kilograms (10.6 U.S. tons) for a crew of 6 heading out to Mars as packaging and switching to glass or metals with water in the containers just put the ship into a much larger sizing.....

Oldfart1939 · 2017-04-20 18:24:26

Food for really long term storage is either dehydrated or freeze dried, followed closely by traditional canned foods. These new irradiated foods don't come close. Zubrin argued for a mixture of whole, fresh foods, (frozen or refrigerated), canned rations, and freeze dried foods. I've eaten an awful lot of less than palatable foods on mountaineering expeditions, as well as in the military. MRE rations seem to hold their taste and texture pretty well, but get old fast, after eating them every day for a while.

Oldfart1939 · 2017-04-20 19:20:14

For prepositioned food on the Mars base, the military used to have what were called 10 in 1 rations. These were tray-like meals which could be heated on an oven or on top of a stove. They were designed to feed 10 soldiers, and weren't too bad tasting. Meals such as beef stew, turkey tetrazzini, scalloped potatoes, macaroni & cheese. They sure beat the H*ll out of the K-Rations for taste The trays were aluminum, hence lighter than canned goods, especially for the quantity of food contained. I don't know if these are still made? Single servings in cans are pretty weight intensive, but larger serving sizes reduces the container weight per serving substantially.

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