Mars Orbit Rendezvous - low-cost and reusable spacecraft

RobS · 2002-12-21 10:56:21

I doubt the governments of the world will let anyone move a comet or asteroid into Earth orbit--even high Earth orbit--any time soon. Even a 100 meter asteroid, if it crashed to Earth, could kill a million people. Even if the chance is small, it would not allowed because of the danger of it getting weaponized.

Maybe in a century after the earth is more politically stable, though.

-- RobS

RobertDyck · 2003-01-12 19:08:37

I met with my aerospace engineer friend over the Christmas holidays. She suggested the reusable interplanetary spacecraft be built from a self-launching hull rather than TransHAB. This would permit sending a very large enclosure with a rigid hull in a single launch. Of course, since self-launching technology is her idea, she is biased towards that. However, this would permit a very affordable yet reusable interplanetary spacecraft.

The other technologies are a high-efficiency life support system, and faster than light communication. A chloroplast based life support system. This recycles carbon dioxide and water into oxygen and carbohydrates. Operation would be entirely within the enclosed environment of the spacecraft, so no gas losses to space. Some carbohydrate could be fed to yeast to produce protein; the result would have the same carbohydrate and protein content as potatoes. Depending on the yeast variety selected, it could either be tasteless or quite flavourful. Some varieties of yeast are very rich in vitamin B complex. The Johnson Space Center's Advanced Life Support project claims to have achieved 97% water recycling efficiency, including water from all sources. Dehydrated food can still be up to 50% water, so a high efficiency system means transporting only dehydrated and dry food. Producing a potato substitute reduces the mass of dehydrated food necessary. Oxygen production would produce so much carbohydrate that it would only be consumed if the astronauts ate nothing but that. Consuming stored food (for balanced nutrition) means production of excess carbohydrate. That would be incinerated to extract all possible water. The result would be 100% oxygen recycling and 97% water recycling, with water loss replenished from residual water within dehydrated food. This greatly reduces the consumables necessary for the mission.

The communications idea is a quantum communicator. I have an idea how to create one, but it requires developing a new microchip. That's expensive. The quantum communicator means instantaneous communication between Earth and Mars. So that means real-time telephone conversations, television, and internet access. It also means a remote surgical suite can permit a doctor on Earth to operate on astronauts on Mars. That permits reducing the crew to just 4.

A spacesuit for Mars would also use a reusable sorbent for carbon dioxide extraction, rather than lithium hydroxide. Reusable sorbents are silver oxide, or solid amines. These mass more than lithium hydroxide, but can be reused by heating. Lithium ion batteries have been developed that can withstand -40?C temperature. Mars can get colder than that, but the inside of the suit must be comfortably warm. Current batteries for the EMU (the current space shuttle spacesuit) can only withstand 30 charge/discharge cycles before they are reduced to 60% capacity. These lithium ion batteries can withstand 1500 cycles before they are reduced to 80% capacity. That means the batteries can endure the entire mission. Eliminating consumable sorbent cartridges and batteries means the only consumable for EVA is gas lost through suit leaks or lost the airlock during depressurization. Eliminating suit consumables also reduces launch mass.

RobS · 2003-01-17 15:28:38

I am curious about your communication faster than the speed of light. It doesn't sound like a technology we'll have working in a decade or two, but who knows.

Robert, I'm concerned or curious about another aspect of your plan. The Mars Ascent Vehicle you postulate would be the smallest and lightest thing possible; just a skin around the spacesuited astronauts, who would have to wear their spacesuits on the trip for life support. I know this has been suggested for the moon. But it seems to me the Apollo spacecraft orbited very low; 60 miles (100 km) or less. From launch to rendezvous was a matter of six or eight hours (which translates into two or three loops around the moon). But the space shuttle has to fly to a 400 km orbit and rendezvous takes twenty-four hours. No doubt, it could be done faster. Yet the Mars Ascent Vehicle has to catch up to a vehicle in an elliptical orbit which has about 400 or 500 km as its periapsis and something like 25,000 km as its apoapsis. If the mother vehicle is in a low orbit the rendezvous could be faster, but then the mother vehicle is rather deep in Mars's gravity well and would take much more energy to achieve trans-Earth injection. Furthermore, the mother vehicle will probably have to execute a plane change to be oriented right for TEI, and that's much easier to achieve at a high apoapsis.

I don't know how long rendezvous with the mother vehicle in a sun-synchronous elliptical orbit (which is what is usually used) would take, but I bet it would be 24 hours minimum, and you have to accommodate the possibility of delays and setbacks. Under those circumstances, a rendezvous could take two or three days. So my guess is that the Mars Ascent Vehicle needs to be more robust than you are suggesting, and therefor more massive. It'll at least need to have waste facilities and food, and it'll have to be pressurized.

Also, a small MAV probably would not transport consumables from the surface to the mother vehicle. The return flight involves about three tonnes of consumables per person. Zubrin's Mars Direct plan aerobrakes the stuff onto Mars in the ERV, then launches it to Earth with the astronauts. Yes, this seems inefficient; but it is also safe, because if the MAVs you are envisioning both fail for some reason, the astronauts will be stranded on Mars while the twelve tonnes of supplies they need to survive will be orbiting above their heads, out of reach. This probably could be solved by leaving the twelve tonnes on the mother vehicle and dropping onto Mars the supplies for the NEXT mission; but then when the next mission arrives, their TV dinners and tang is two years old, and might not taste great.

Any ideas about this problem?

-- RobS

Adrian · 2003-01-17 15:45:57

Hmm, I am also curious about the FTL communicator. From what I know, there isn't any physics that allows for the transmission of information at faster than light velocities. In fact, I recall that if such a thing were possible, it would violate causality. But I'd be interested to hear your idea.

Josh Cryer · 2003-01-17 18:01:32

I bet it has something to do Aspect.

I read that it wasn't workable, due to the uncertainity principle. You can't transmit data, but you can transmit a signal (albeit 100% unreliably- it's luck really).

But yeah, I'm interested in hearing too.

RobertDyck · 2003-01-17 19:17:55

Arrival of the interplanetary spacecraft would aerocapture into highly elliptical, high Mars orbit. Aerocapture would involve dipping into Mars atmosphere, so it would approach Mars from behind then pass across the "front" of Mars during aerocapture. Normally this would result in the periapsis being in "front" of Mars as it orbits about the Sun, and the apoapsis being "behind" Mars. The orbit would be in the same plane as Mars orbit about the Sun. However, the orbit could be controlled during aerocapture to loop around Mars so the periapsis is "behind" Mars and the apoapsis is "in front". One half Mars year later (343.5 Earth days) the "front" of Mars would have rotated 180? but the orbit would not, so the apoapsis would be "behind" Mars. Departing on this trajectory would leave the spacecraft with a slower solar orbit than Mars so it would fall inward toward the Sun, toward Earth. The exact orientation of the elliptical orbit could be controlled for optimal orientation at time of Trans-Earth Injection (TEI).

Notice this design uses a reusable interplanetary spacecraft. All food and supplies for the return trip would be included. That means supplies for return are waiting in orbit for the astronauts. The only things sent to the surface are those things which will be left on the surface (except the astronauts themselves). In addition to efficiency, this has the safety feature that in the event that a free return is required, the spacecraft can loop around Mars and return directly to Earth, and it will already have supplies for the return trip. The MAV would only carry the astronauts, samples, and enough fuel for TEI.

soph · 2003-01-17 19:24:27

and the communicator?

RobertDyck · 2003-01-17 19:34:59

Um, maybe I shouldn't have mentioned the communicator. It can be built using technology I know about today, but it does require a new microchip and one piece of new manufacturing equipment. Since it is a single microchip it can be applied as a new form of wireless telephone to replace cell phones. It would have the advantage of no cell towers so much less expensive to operate, and very inexpensive to install a new system. It would also permit wireless telephone carriers to operate worldwide, or wherever their marketing guys go. It could also be used for a cable TV box, without the cable or satellite; this would make cable and direct TV obsolete. Gangs of these chips could be used for a trunk line, so communication between telephone exchanges without wires, optical fibres, microwave towers, or satellites. It could make the concept of a communications satellite obsolete. Since it would be completely secure and produce no detectable signal, the military would love it. Let's just say "no yet patented".

orionblade · 2003-01-17 21:40:41

this is exactly what we're talking about with our balloon mission. Our landers will require oxygen to stay warm, or at least can use it instead of sheer electrical power, and won't have enough of a mass budget to handle the high pressure tankage for pure hydrogen. What happens with water is the hydrogen and oxygen are bonded together, which requires a small amount of energy to break them apart, but they literally hold themselves together for the voyage. The vapor pressure for water at orbital and interplanetary temperatures, and at mars surface temperatures, is thousands of times lower than that for liquid oxygen or hydrogen. The difference between the vapor pressure for ice at orbital and mars surface temperatures is very small, however for cryogenic fuels of any sort, a small temperature change can drastically increase the amount of boil off experienced. This results in a net loss of propellant. I can store our ice in a lightweight polyethylene container similar to an RC aircraft or car fuel tank normally used for methanol or gasoline, run some electrodes in wrapped around a dual channel tube to collect the two gases, and either use solar concentrators to melt the ice, or use a small nichrome heater wire. in any case, the energy required for the electrolysis is actually only about twice that required for a solenoid valve, which will be eliminated (potentially) in a design using electrolysis to inflate the balloons, so one more potential frozen component is eliminated. We just have to come up with a way to eliminate steam from the system, so I think we'll just have a convoluted perforated tube, or some sort of foam filling the tank so that any steam would refreeze, then be melted and electrolyzed before it left the tank, otherwise, the balloon could be filled with vapor, lift off, then have the steam freeze on the inside of the balloon, and it would no longer provide lift, and that difference could cause the balloon to crash. Its something we'll need to test this winter or next winter outdoors or in a large freezer before we go much farther with the design, because one entire lander's payload depends on the success of the balloon system.
So yes, as long as you can separate steam from oxygen and hydrogen in a zero gravity environment (where a fractioning column wouldn't work) you can use ice instead of separate high pressure cryogenic tanks for your fuel, and eliminate boil off to 0%.(you'd have to get the ice up pretty hot before it boiled off to any degree that your tank couldn't handle).
Take it easy y'all,
Rion

RobertDyck · 2003-01-18 01:55:09

Rion, you keep focusing on your particular project. You will notice I did not repeat the Roadrunner project on every threat throughout this board. If you are interested in work on Roadrunner, please read the thread "Mars Society Initial Mars Mission" under the "Mars Society International" category. By the way, I feel Adrian should delete the MOLTOV thread under "Human missions"; you already have a thread by that name under "Unmanned probes". This thread is for discussion of this particular mission plan. I exercised the courtesy of not flaming your project, despite its obvious duplication of ours. If you wish to discuss merging projects please do so under the aforementioned thread.

RobS · 2003-01-21 16:39:28

Robert, are you still thinking about my comment that maybe the MAV has to be bigger? I wish there were a way to estimate the length of time one needs from launch to rendezvous with the mother ship in a very elliptical orbit. those guys in spacesuits might have to wait a long time before getting access to a real bathroom!

-- RobS

RobertDyck · 2003-01-21 22:53:17

A high orbit will require higher energy than a low orbit. However, if you time MAV departure to coincide with the mother ship swing by its periapsis, then the MAV has a relatively short distance to rendezvous. The space shuttle often enters orbit completely out of phase with the ISS. It then enters a slightly lower orbit to catch up. The "catch up" takes hours, typically several orbits, and yes it can take a day. This is done so they can launch in any orbit that passes over KSC. It is much quicker if you time it so the ISS is in correct position as well as passing over the Cape. If you park the mother ship in an equatorial orbit, and land close to the equator, then you can rendezvous with every orbit; that permits timing rendezvous with the mother ship passing overhead.

orionblade · 2003-01-21 23:26:18

as a matter of fact, you do keep talking about your mission/projects. I don't really see how anyone can contribute to the forum without making at least a passing reference to their own perogative. In my case, the way I learn about things is by doing, not by simply reading or going to class. My last post was in reference to the inflatable tank idea several posts earlier, using ice as a propellant storage concept, so I related it to the mission which I have been designing for the past two years, since it is what I know, and I did not wish to extrapolate on topics with which I was not familiar. Adrian has corrected the error of my ways insofar as posting off-topic, but this most recent post in this forum would seem to me to be quite on topic with prior posts by other members.

As far as the accusation of duplicating your mission, I hardly see how your mission is unique, since you yourself admit using Zubrin's idea of inflating balloons with methanol and the like. I hardly think mine is terribly original either, but I certainly did not take your idea. Often in history several researchers have come to the same conclusions, or at least remotley similar ones, on the same topics. Whittle and Ohain both came up with the jet engine around the same time, but lack of mutual knowledge is questionable, but other developments have resulted in quite similar technologies hitting the market at nearly the same time. Sometimes there is only one way to do something easily.
I'll go on and stop here, since any bickering between us is counter productive to the purposes of this forum. Just to let you know I sent you a personal message through the board's messenger function several days ago regarding my areas of research and with several questions about yours, but since I have not taken the time to download the entire site and read it offline yet, I had no prior knowledge of your mission plans. If you would like to discuss it in more detail, please email me at chi2orionis@hotmail.com, or simply reply to my message on the board's messenger, assuming it was delivered/sent correctly.
As for the other members of the forum I apologise for any incursion into your otherwise harmonious enjoyment of the information presented here. I am new to the forum, and am not exactly a part of your community yet, though I hope to fully integrate myself within the framework which has been laid out thus far. The invitation to inquiry via email extends to all.
Thank you, and good night,
Rion Motley

RobertDyck · 2003-01-22 10:41:19

Answered in your MOLTV thread under "Unmanned probes". Let's keep this thread on topic. There are several components to a manned mission, and reducing weight for all of them will reduce cost. The more you reduce cost the more likely the mission will happen; but let's not introduce other missions.

cyclohm · 2003-02-26 01:08:57

RobertDyck,

I work for a semiconductor company. If you can provide the schematic, an advanced BiCMOS process MAY be available. We run test wafers for trying out new ideas every few months. Adding another chip to the line-up could be really easy and not cost a dime. (The company attitiude is that the money is being spent anyway, so do your experiments on the test wafers.)

You would need to provide at least a schematic, but I could not provide you with non-disclosure as I'm sure that said semiconductor manufacturing company would be hard pressed to let property rights outside of their tight fingers if device were to function. However, I could assure you with proper credit - and if it did work, probably a very well paid job.

RobertDyck · 2003-03-01 10:50:46

That is a very intriguing offer. However, any salaried job is based on the work done for that salary, not any work done prior to hire. That means if I just give my idea away to your company then I would not get a secure, well paid job. Furthermore, as you said the process to manufacture the chip MAY be available. I would be a fool to just give away my idea without any secure method of compensation. As for the schematic; my idea deals with the transceiver. I still need a communications engineer to work with me to interface this to a cell phone or cordless phone. That sounds like another excuse to avoid paying me for the invention. If there is some way to get your employer to sign a non-disclosure then I would jump at the chance. I would give them first right to purchase the rights to the device. I would offer to pay for custom chip manufacture, but I expect it would cost more than I can afford.

Euler · 2003-03-07 21:20:58

I don't see how a practical FTL communications device could be made using quantum tunneling. However, there is another quantum phenomena that I have read about that may allow FTL communication. In quantum entanglement, two particles become related so that if the spin of one becomes known, it instantly causes the other particle to have the same spin. The information about the other particle's spin therefore travels faster than light. Albert Einstein referred to this possibility as "spooky action at a distance." Recent experiments have shown that entanglement does in fact occur, and that it information about the quantum state of one of the particles does indeed travel faster than light. FTL communication based on this idea may be possible some time in the future.

SpaceNut · 2018-11-25 17:07:46

bump
Fixed all artifacts in topic

The interesting thing is we are talking now about using laser light to do mars to earth communications as it was proven as a capable means for moon to earth.

New Mars Forums

Announcement

#26 2002-12-21 10:56:21

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#27 2003-01-12 19:08:37

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#28 2003-01-17 15:28:38

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#29 2003-01-17 15:45:57

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#30 2003-01-17 18:01:32

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#31 2003-01-17 19:17:55

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#32 2003-01-17 19:24:27

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#33 2003-01-17 19:34:59

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#34 2003-01-17 21:40:41

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#35 2003-01-18 01:55:09

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#36 2003-01-21 16:39:28

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#37 2003-01-21 22:53:17

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#38 2003-01-21 23:26:18

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#39 2003-01-22 10:41:19

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#40 2003-02-26 01:08:57

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#41 2003-03-01 10:50:46

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#42 2003-03-07 21:20:58

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

#43 2018-11-25 17:07:46

Re: Mars Orbit Rendezvous - low-cost and reusable spacecraft

Board footer