Mars Mission "Alpha."

Oldfart1939 · 2017-04-15 11:31:57

To all, and especially SpaceNut, administrator.

I'm starting this new thread in the hopes we can maybe start with a clean sheet of paper and avoid some of the acrimonious commentary that's popped up on several other threads. Should that occur here, I invite the administrator to just delete the thread.

We have quite a few regular contributors here, each one of us with a different vision of what the first manned mission, and hence pioneering settlement will be like. We're all familiar with Dr. Robert Zubrin's foundation cornerstone mission concepts, but time has passed, and capabilities have progressed from the somewhat crude Mars Direct mission architecture. There have been lots of great ideas and plenty of creative thought posted here, as well as lots of rude, snide, and condescending comments in criticism thereof. That shit will not fly on this thread, and if it begins, I'll request the admin simply "pull the plug" on it.

Rules of this game: Each regular gets one initial post wherein he presents a detailed mission plan, or realistically timeline and follow up for the first human crew on Mars. What must be included is the means of transportation that's realistic, crew size, what will be taken along, what will be prepositioned, how the crew will be housed, fed, provided with water, sanitation, air, and means of Earth return. The initial posts must not make reference to, or criticize any preceding post by any other member. In the follow-up posts, the gloves come off.

Since I started this endeavor, I'll start things off with my vision of the timeline and necessary events leading to, and accomplishing the first manned Mars mission. And no, this isn't intended to be a "Flag and Footprints" deal. We're (mankind, that is!) going to Mars to stay!

Oldfart1939 · 2017-04-15 12:07:25

What we're initially limited by are the Hohmann Transfer windows, and the basic fact that no one other than NASA has ever successfully landed anything on Mars. Elon Musk made waves last year with his announcement that SpaceX was preparing to send a Red Dragon mission to Mars during the 2018 Hohmann Transfer window, a position since moderated by the company's commitment to it's customer base. Musk subsequently announced his humongous Interplanetary class spaceship (not yet built, but a concept). Nowhere have we seen anyone building, or even threatening to build, the "tuna can" Hab type spacecraft promoted by Zubrin, et. al. So...what I'm proposing here is strictly based on the Red Dragon-type space vehicle and possible extensions thereof. This necessitates a timeline based on limited capabilities of throw mass to LEO.

2020: Demonstration flight of Red Dragon capability; demonstrate ability to enter Mars orbit, select and land at predetermined landing site. Vehicle should carry several experimental devices, including but not limited to an experimental Moxie unit, a Sabatier reactor, and a rover capable of setting out a set of landing zone transponders for subsequent Red Dragons.

2022: Follow-up Red Dragon mission, could preposition complete food supply for the first crew--adequate for 550 days. Could transport a tracked SAFE-400 nuclear reactor to be prepositioned. Based on success of the 2020 mission, there could be several Red Dragons flown and landed,; one could carry a complete, or parts of a Bigelow expandable Mars Habitat. Another Red Dragon could bring a larger-scale Moxie unit or functional Sabatier system. Could utilize the spacecraft volume to accumulate a fuel supply for a hydrocarbon/LOX based rover.

2024: Preposition the first ERV, additional landings with other Habitat structure, possibly a tracked or 6 WD small rover, and a second SAFE-400 nuclear reactor. Bring another complete mission food supply and possibly a reserve of return flight fuel as a backup in case Sabatier system is not as efficient as hoped and planned. Land a central "hub" to which Bigelow expandable modules could be attached; would contain the airlock system, and basic laboratory equipment, kitchen, restroom and other sanitation equipment for the base. Another lander could bring a Bobcat with front loader for partial burial of the Bigelow system.

2026: Two fully crewed landers, along with another ERV; 4th lander brings more food and construction supplies for a basic greenhouse, backup Solar panels, minimal hanndtools.

2028: new crews land, older crews depart or stay, per desires.

This is my bare-bones mission model based on today's existing technology.

Next?

louis · 2017-04-15 12:16:31

Oldfart1939

Sounds pretty realistic.

What is the overall "cargo" tonnage (i.e. excluding structure of the craft and the humans themselves) you plan to land before 2028? What tonnage would you need to get to LEO in total?

Oldfart1939 · 2017-04-15 12:24:29

Louis-

My model requires some in LEO construction in order to get sufficient boost into the Hohmann transfer trajectories. I didn't want to muddy the waters with TOO MUCH engineering details at this point, but everything is based on a scale-up of the existing Dragon2 capsule with the cargo trunk physically incorporated to the cone structure. Estimate 22 metric tonnes per flight, but net weight subsequently landed would be less after retropropulsive landing burn.

Dook · 2017-04-15 12:28:33

My idea is essentially, Mars Direct.

First pre-exploration mission 2033
Launch 1: ERV with built in Moxie unit
Launch 2: Nuclear reactor or RTG
Both vehicles dock together on orbit and go to Mars as one spacecraft. Docking connects the nuclear reactor to the ERV/Moxie.

About One Year Later: Exploration 2035
Launch 4: Rover hanger with long range rover, a cart, and some supplies
Launch 5: Tuna can habitat crew of 4. Has solar panels, food, and water
Rover hanger and the tuna can dock together in orbit and go to Mars as one spacecraft.

Two more exploration missions would take place, both at the same time. Two pre-launched ERV's in 2049 and two tuna can with crew and rover hangers in 2050.

First Settlement: Starting the Mars Base, about 2065
Launch 1: MOXIE unit
Launch 2: Nuclear reactor or RTG
Both vehicles dock together in orbit and fly to Mars as one spacecraft.

A few days later:
Launch 3: MOXIE unit
Launch 4: Nuclear reactor or RTG
Both vehicles dock together in orbit and fly to Mars as one spacecraft.

A few days later:
Launch 5: Hard plastic panel greenhouse #1
Launch 6: Food, water, hydroponics
Vehicles dock together and go to Mars as one.

One year later, about 2066:
Launch 7: Rover, two ATV's, rover hanger, and some supplies
Launch 8: Tuna can with 4 crew, food, water, 4 chickens, 4 tilapia fish, solar panels
Vehicles dock together and go to Mars as one.

Second Settlers: about 2082 or whenever Mars is closest
Launch 1: Rover, rover hanger, lots of supplies
Launch 2: Hard plastic panel greenhouse #2
Vehicles dock in orbit and go to Mars as one.

Seven months later:
Launch 3: Tuna can with 4 crew, food, water, 4 chickens, 4 tilapia fish, solar panels
Launch 4: Hard plastic panel greenhouse #3
Vehicles dock in orbit and go to Mars as one.

Third Settlers: about 2083
Launch 1: Tuna can with 4 crew, food, water, 4 chickens, 4 tilapia fish, solar panels
Launch 2: Food, water, spare parts
Vehicles dock in orbit and go to Mars as one.

The three exploration missions would land all over Mars and the crews would return home.

The settlements would be in one location just north of the equator and all incoming settlers and equipment would land as close as possible so one established trail could be used to bring equipment to the base using the long range rovers.

So, with 14 launches we get a Mars base with 12 people living in three tuna can habitats, they have three rovers, two Moxies with RTG's, a solar panel farm, and three large sturdy greenhouses.

Once we have two operating Moxie's at the base each powered by it's own RTG we should have plenty of oxygen and not need to send a Moxie and RTG with every launch of new settlers. By that time we would, hopefully, have the greenhouses, chickens, and fish/algea tanks doing well.

After the exploration is done there are no more ERV's. It's settlement.

Last edited by Dook (2017-04-15 12:31:17)

louis · 2017-04-15 14:02:47

H2MARS MISSION - PHASE ONE

BACKGROUND:

The Space X transit architecture would suit. I am of course assuming a Falcon Heavy to lift tonnage to LEO. However this is my own take.

Essentially the H2Mars (Humans to Mars) Mission architecture has the following main features:

1. Orbital assembly of Mars Transit Vehicle comprising Bigelow-style hab, supply and life support module, lander craft, fuel module and rocket engine.

2. Pre-landing of supplies and robots.

3. Apollo style lander approach for landing humans on Mars (ie fairly minimalist craft).

4. Use of PV as the main power source.

5. Six people landed as part of the mission - The Pioneers.

6. Total tonnage landed on Mars surface: about 62.5 tonnes. Total tonnage to LEO - c 300 tonnes?

Pre 2020 -

Identify preferred landing site. Provisionally located at 25 north and 26 west

Design pre-lander robots and supply units and HLC (Human Landing Craft).

2020 - (2 transits) Put two dedicated COMS and survey satellites into Mars orbit. Land 5 mini-rovers (enter Mars orbit in one craft that then splits during descent to allow the mini rovers to land in different areas). These mini rovers will scout for water and iron ore resources and assess the terrain. The best landing zone will then be selected. Total tonnage landed: 1 tonne.

2022 - (2 Transits) Using the mini-rovers as transponders, the first pre-landing supply unit is landed. This will comprise an automatic PV panel system of about 1000 sq metres which keeps a series of batteries charged (used by Rovers to charge their own batteries). In a second landing, a Landing Zone Robot Rover (LZR) will be landed. The LZR will automatically remove boulders and rocks out of the landing zone (500 by 500 metres) and lay down transponders on the perimeter. The LZR will also be available to serve subsequent static landers that require power charging. Total tonnage landed: 2.5 tonnes

2024 - (4 Transits) Land Water Locator Robot (WLR), Resource Processing Unit (RPU), Robot Gas Vehicle (RGV) and gas holder tanks (GHT). The WLR will scoop up the ice bearing soil and isolate the water, which will then be delivered to the RPU. The RPU will compress and process the Mars atmosphere to produce oxygen, argon and nitrogen. The RPU will produce methane and oxygen. The RGV will deliver the products to the GHTs. Total tonnage landed: 10 tonnes

2026 - (4 transits) The Main Hab, main PV panelling and two supply landers will be landed. Supplies will include food, water, scaled down industrial machines and two small 3D Printers. Total tonnage: 9 tonnes.

2028 - (6 transits) The Farm Hab, Two Supply Landers, Industrial Hab, 2-person Human Rover, and two Human Landers (with 3 crew in each) will be landed.Total tonnage landed: 50 tonnes.

The LZR will mark out the precise landing area for the Human Landers.

After 48 hours, the two crews transder to the Main Hab.

2028 - 2030 Activities include:

1. Locating and mining metals and other materials at the surface. Also locating of best water resources.
2. Producing pure materials e.g. pure iron.
3. Splitting water into hydrogen and oxygen.
4. Dissociating the atmosphere into its constituent parts and isolating carbon.
5. Creating metal and plastic powders.
6. Facilitating injection moulding.
7. Casting basalt.
8. Producing plastic and steel and other metal products on a small scale.
9. Recycling waste materials.
10. Making bricks.
11. Making glass.
12. Exploration of the surrounding area to a limit of about 100kms.
13. Clearing of "roads" leading away from the base to interesting areas.
14. Experimental work on creating habitat space.
15. Farming - primarily salad vegetables and bean sprouts.
16. Self monitoring for medical condition.
17. Manufacturing rocket fuel.

2030 - Four human landers with 12 replacement Pioneers land at Chryse City. Return Ascent Vehicle is landed and fuelled with rocket fuel produced on Mars.

louis · 2017-04-15 17:48:46

Dook, Why the long, long gaps between Missions, when launch costs will be down to $1000 per kg or less?

Dook · 2017-04-15 17:56:46

Why the long gaps between missions? Because that's when Mars is closest.

louis · 2017-04-15 17:58:41

You seem to have a gap of 14 years between 2035 and 2049. What exactly is preventing you going earlier than 2049 with the next phase?

Dook wrote:

Why the long gaps between missions? Because that's when Mars is closest.

Dook · 2017-04-15 18:12:13

louis wrote:

You seem to have a gap of 14 years between 2035 and 2049. What exactly is preventing you going earlier than 2049 with the next phase?
Dook wrote:
Why the long gaps between missions? Because that's when Mars is closest.

The distance from the Earth to Mars almost doubles during those years. That's why I wouldn't launch in that time.

SpaceNut · 2017-04-15 21:12:01

Lets take one step at a time then if we can not follow set down rules....so I will contribute to the engineering details.

2020 demonstrator mission details:

Moxie is slated for Nasas 2020 mission but its tiny in comparison to what man needs to prove out.

https://mars.nasa.gov/mars2020/mission/ … cientists/
MOXIE itself will be a reverse fuel cell, developed at the Massachusetts Institute of Technology, converting CO2 into oxygen and carbon monoxide via solid oxide electrolysis. The 2020 Nasa mission is a 1% build with full scale MOXIE to launch hopefully 2030s that will prepare liquid oxygen tanks or equivalent to be used. This is also when we need nuclear power as solar will not be enough to operate 24/7 once man is there.

The reason for Moxie and other insitu propellant equipment is as follows. "To get 30 tons of oxygen on the surface of Mars, you need to launch 300 to 450 tons of propellant from the surface of the Earth into Earth orbit." Of which 75% will need to be oxygen to allow for it to burn.

Right now, MOXIE is designed so that it will operate for 50 Martian days (about 51 Earth days) and will produce about 20 grams (0.7 ounces) of oxygen per hour but the full scale unit is to produce about 2 kilograms of oxygen per hour.

The carbon monoxide (CO), a byproduct of the reaction, may also be collected and used directly as propellant or converted to methane (CH4) for use as propellant. This will mean another holding tank to scale to size, pumps, valves, support electronics ect....but we would not want to lose the compression energy or of the conversion into oxygen by direct venting so it have an energy value for what we do next with it.

Power utilized for the demonstrator is 300W for about 10 grams per hour. The compression will be done with https://airsquared.com/news/scroll-comp … mars-2020/ Design Specifications are on the page.

Solid oxide electrolysis cell can be read about here https://en.wikipedia.org/wiki/Mars_Oxyg … Experiment

The Sabatier reactor is currently in use as a demonstrator onboard the ISS to which there has been several issues. So any unit sent on the futuristic mission of 2020 would also need to be a step above what we are trying for as well as noted with the moxie we need to strive for insitu propulsion scaling and timeline as meantion earlier hopeful 2030 mission.

https://www.nasa.gov/pdf/181148main_Sabatier_merged.pdf full of alphabet soup.....
http://www.swri.org/3pubs/ttoday/Summer … to-H2O.pdf
http://www.mashpedia.com/Sabatier_reaction

A 2011 prototype test operation that harvested CO2 from a simulated Martian atmosphere and reacted it with H2, produced methane rocket propellant at a rate of 1 kg/day, operating autonomously for 5 consecutive days, maintaining a nearly 100% conversion rate. An optimized system of this design massing 50 kg "is projected to produce 1 kg/day of O2:CH4 propellant ... with a methane purity of 98+% while consuming 700 Watts of electrical power." Overall unit conversion rate expected from the optimized system is one tonne of propellant per 17 MWh energy input.

http://www.tda.com/Library/docs/05ICES_ … evised.pdf
http://www.pennenergy.com/articles/penn … ction.html

Dook · 2017-04-15 21:56:06

SpaceNut:

Do you have an idea of the size and power requirements of the full scale MOXIE?

louis · 2017-04-16 03:02:23

Regarding obtaining oxygen from water, I read on the internet that it takes about 50 kWh of electrical energy to convert 9 kg of water into 1 kg of H2 and 8 kg of O2 by means of commercially available electrolyers. Not sure if anyone can confirm that.

I understand also we need about 2.2 kgs of oxygen per person per sol. So for a 6 person colony that's 13.2 Kgs.

So let's say, to give a margin of safety, we need 100 Kwhs per sol per day to produce 16 Kg.

Isn't electrolysis of water relatively mass light?

For the first mission, we could of course just land 12 tonnes of oxygen to cover their oxygen needs - that would be the brute force solution and I am sure we will take along a tonne of it in any case.

SpaceNut · 2017-04-16 07:45:39

Dook wrote:

SpaceNut:
Do you have an idea of the size and power requirements of the full scale MOXIE?

The amount based on linear scaling is 30,000 watts but when you add in the way that we need the oxygen for a crew its going to be even larger and that is at a continous run. As louis noted the next step in fuel creation requires a source of Hydrogen which from electrolysis is another Electrical source penalty. With fuel requiring 75% oxygen to go with the methane created via the Sabetier reactor.

That said 10 grams for methane (*2.5) and 20 grams of oxygen (*3.75) at 700w using raw hydrogen feed stock and 300 watts for making the oxygen leaving for the corrected ratio of 1750W for CH4 and 1125W for oxygen making a total power required for the balance of fuel and oxydizer of 2875W from the power source.

Sure the first will also have a penalty for recycling of O2 for the crew but the benefit is Co2 is already at pressure that is able to be turn into fuel without the penalty of gathering it from Mars Atmosphere though the quantity available is probably simular to as if it were at mars pressure for the energy consumption.

We also need to be careful when expressing wattage as a watt is voltage x current instantaneous during the second of measurement and not over the hour time period for consumption to which it could fluctuate quite a bit to give what is the average power in that time period written as Wh. This also defines the time period to which is required to make the function happen when looking at quantities as well.

GW Johnson · 2017-04-16 11:16:17

“Johnson’s Folly”

My inputs toward a manned Mars exploration mission design are posted over at http://exrocketman.blogspot.com, as the article titled “Mars Mission Outline 2016”, dated 5-28-16, with search and filtering keywords “launch”, “Mars”, and “space program”. This mission design has nothing to do with “Mars Direct”, “Mars Semi-Direct”, the “Design Reference Mission”, or any other modern mission design. Instead, it is an update to a very adaptable 1950’s concept.

That cited article proposes sending a crew of 6 to Mars, landing for short periods at multiple sites in crews of 3 with reusable landers, and supplied with propellant from Earth to make up to 9 landings. Under the mission rules I posted in the article, this is really only 8 landings, at 8 separate sites, during the one mission to Mars. The propellant for the last excursion is held in reserve for rescue purposes. One of the key features of that mission design is “a way out” at every phase of the mission.

I sized that mission such that, under the assumption that direct launch costs are no more than 20% of total program costs, landing those crews of 3 at those 8 sites on Mars could be done by “New Space” for under $50 billion! “Old Space” would demand something like at least 10 times that budget. There is nothing in my design that cannot be launched with a Falcon-Heavy or smaller. Orbital assembly is required in Earth orbit, so this is best done adjacent to a space station where the assembly crew can live. If you can launch 15-20 ton payloads to low Earth orbit, you can build this thing. Most of the assembly is docking things together and making wiring and plumbing connections.

The only major new vehicle development effort required to carry this out was a reusable one-stage “landing boat” powered by monomethyl hydrazine and nitrogen tetroxide. This item would have to be assembled from components in low Earth orbit because of its heat shield diameter. I showed it to be easily feasible in another “exrocketman” article titled “Reusable Chemical Mars Landing Boats Are Feasible”, dated 8-31-13, with search/filtering keywords “Mars” and “space program”.

I picked the storable propellant version from that cited lander article for this mission design, so that common propellant supplies can be shared and re-allocated as the needs might arise. These lander designs also feature abort-to-surface for the crew, because the mission architecture provides for surface rescue capability from low Mars orbit. I have seen no other modern mission designs that provide that rescue capability. Since I have shown that it really can be done, I now consider not providing self-rescue capability (just for technical convenience) to be unethical.

The overall mission architecture that I propose presumes that Earth return propellant, and the lander propellant and landers, are sent ahead unmanned to low Mars orbit by solar electric propulsion, unconstrained by mission times in space. The men follow in a reusable orbit-to-orbit transport vehicle that provides them radiation protection and full one-gee artificial spin gravity both ways. This manned vehicle is recovered and reused for future missions to Mars, Venus, Mercury, the main asteroid belt, and the near Earth orbit (NEO) bodies. Surface crews “camp out” in the rather spacious landers, which are their ascent vehicles as well. Empty propellant tanks and the Earth departure stage are the only jettisoned items.

What I propose here is that very same mission architecture, updated to send even more lander propellants to Mars, so that up to 15 surface excursions are covered. This is still under $100 billion, under the same 20% launch cost and “New Space” assumptions. That way, up to 14 surface explorations at up to 14 different sites can be done, during the nominal 13 months spent at Mars before embarking on the Hohmann transfer home. And not once did I assume anything larger than Falcon-Heavy was needed to launch the components.

The basic idea with the reusable lander is to sacrifice payload fraction for two-way single-stage reusable flight on one propellant load. At ~3% payload fraction, these are large, spacious vehicles, which means that there is plenty of room to “camp out” in the lander at each of the up-to-14 sites, for just-less-than-a-month’s surface stay at each site. No disposable “tuna can” habitat is required, either in flight between planets, or on the surface at Mars. No separate ascent vehicle is required, either. Most of the sites will see just one item landed. This avoids a lot of “oops, I missed the landing zone” risks.

Self-rescue capability is obtained by alternating crews to the surface, with at least one lander always available for a rescue mission. I send three landers so that the loss of one does not end missions to the surface. One crew does science from orbit while the other is on the surface. This provides a “safety watchdog” over the crew on the surface, while also staying very healthy in spin gravity aboard the transport. Being in low Mars orbit, the proximity of the planet provides shielding to crudely cut the cosmic ray exposure to half that in free space. The surface crew gets that plus the shielding effect of the atmosphere. Use a wireless connection to free-flying instruments to avoid complicated counter-spin designs.

The only requirement to land multiple payloads at any given site would occur for a re-visit or rescue. Dropping a few small GPS-like satellites into low Mars orbit covers most of that contingency quite handily. But, each site’s landing place should also include a radar beacon for possible revisits. Beacon lifetime should be multiple years, to cover revisits in subsequent missions, as well as during the 13 months of the initial mission.

The fundamental idea here is to try out each of these sites “for real”, with in-the-field suitability verified experimentally for multiple methods of propellant and life support chemical manufacture, without ever assuming “a priori” that any such activities will be successful at any given site! Massive “for real” resource utilization machinery need not be sent to every site. Instead, small lightweight experiments go down as part of the site suitability evaluations. The bigger stuff only goes to the “best” site near mission’s end.

Whichever is the “best” site, that is where you leave behind the robotic equipment making propellant and life support supplies for future missions. That will eventually be your permanent settlement site! You DO NOT need to know where that site is located before you reach Mars with men for the first time, in my mission design! But leaving the automated facility running is the true “draw” for future missions, whoever sponsors them.

The idea is to establish that permanent robotic “base” at the “best” site, as determined “in the field” on the very first manned mission to Mars. It is my opinion that there will likely be one, and only one, manned mission to Mars that is government-funded. Without that robotic base, it is unlikely that private concerns would follow up anytime “soon” with return missions. Governments most certainly will not follow-up at all.

Because there is likely to be only one government-funded manned mission to Mars, and because it is so difficult to send men all that way and return them, it seems incredibly stupid to me not to land on the first mission. Why do expensive rehearsals? Just get on with the show! Which means you must be fully prepared to cope with the unexpected.

It is subsequent missions (not the initial mission) that add nuclear power reactors, lots of solar panel equipment, major propellant-manufacturing equipment, major life support-manufacturing equipment, 3-D printers, and big-habitation construction equipment, to that “best” site for a long-term permanent base or settlement. The first mission need leave none of that behind, except at smaller scale to show that it really works automatically.

As you can tell, my fundamental assumption behind all of this is that there will be one (and only one) government-funded mission to Mars with men. The corollary assumption is that subsequent private-entity missions will be few and far between, unless a site has been identified on that first mission that can demonstrably support future development. To expect otherwise is extremely unrealistic, given the history of Apollo at the moon!

Because (1) there will likely be one and only one government-funded mission, and because (2) exploration is better done from smaller vehicles of different capability than base-building missions, the architecture here is an orbit-to-orbit transport and two-way “landing boats” of limited cargo capacity. The key advantage of this multiple-excursion design is evaluating multiple sites for “ground truth”, which has always been at variance with remote sensing. (It is the analog to doing all the Apollo landings in one flight to the moon.) Until you actually go and drill or dig deep, you cannot know “for sure” what is there. It is very difficult to do that without men on site.

Subsequent missions to establish some sort of manned surface base might use a similar but larger transport, and multiple one-way cargo landers of high payload fraction. Crew landers should be similar to my two-way one-stage idea to preclude the risk of traveling to separate ascent vehicles. (The alternative to all of that is Musk’s idea of landing the entire spacecraft as a giant cargo carrier.) The point of the subsequent missions is using big cargoes to build a base, which is quite different from the point of initial exploration (to find out what all is there, and where exactly it is). So, of course the vehicles and equipment are different.

About the only nuance I didn’t add into my exploration mission design would be to also send ahead one or two of the one-way high-payload landers. These would ferry down bigger versions of the initial facility ISRU equipment to that “best” site. That might push the price tag into the $100-200 billion range if done by “New Space”. Two lander designs would need to be developed. More tonnage would have to be launched for orbital assembly. You get what you pay for.

However, by substituting cargo mass for ascent propellant mass in a final one-way trip, one landing boat could ferry down the heavy stuff as a second lander sent to the “best” site. The pilot goes back with the surface crew in the other lander. This does require that all three landers still be operational at mission’s end, so that surface rescue capability is maintained. What this does is allow the surface crew to set up the heavy machinery and leave it running.

You cannot do that with only two operational landers, but there is a fallback position. You can send the machinery down to the best site in an automated one-way landing. You just cannot set it up and leave it running. But it is there for the next crew to set up and use, on some subsequent base-building mission.

This is definitely NOT a flag-and-footprints mission design. Multiple sites get surface evaluations with men present to adapt to the unexpected. Seeing unexpected things is something that you must expect, as contradictory as that sounds. Men visit Mars on the first manned trip. They leave behind the essential core of a permanent base, which subsequent trips can build upon. They stay fully healthy during the entire 31 month mission. And there is a “way out” designed-in at every phase of the mission.

Do this with “New Space”, and you’re likely out ~$100 billion, and it’ll take around a decade to do. Do this with “Old Space”, and you’re likely out closer to ~$1 trillion, and you’ll be lucky to go before 2040 or 2050. Whether NASA can adapt to “New Space” ways of doing things remains to be seen. But with the commercial cargo and crew initiatives, at least there is hope.

Any takers?

GW

Last edited by GW Johnson (2017-04-16 11:27:15)

Oldfart1939 · 2017-04-16 12:20:58

My Original Post above was based on several posts I made in the "Mars Direct, Semi-Direct, etc " thread listed under human missions. basically, I was making an attempt to cobble together a set of components proposed to be available in a realistic time frame--not requiring a completely new batch of yet-to-be-designed-and-built components.

I make no assumptions about ever getting a tuna can habitat landed, since no one other than Robert Zubrin is still talking about such. We either go with what we can get quickly, or we see this endeavor drag on another 50 years before the first "Old Space" Trillion dollar missions. AS far as I can tell, none of the aerospace firms are working towards anything resembling the tuna cans, other than Orbital ATK's Cygnus concept. That's way too small to be considered for anything other than the preciously discussed "2 man one way suicide mission."

What we have, or will have shortly, is the SpaceX Falcon Heavy, now upgraded to a 63 metric tonne to LEO, and the 5 meter diameter fairing for the maximum vehicle diameter. We have the Dragon 2 capsule which is soon to become "man rated." The circumlunar flight will demonstrate the "proof of concept." At this point, we "dance with the girl we brung to the dance." I can see the Falcon trunk module lengthened in order to provide additional living space during the Hohmann transfer, and also mated to a somewhat modified Falcon second stage for the TMI power "in orbit." The lengthened trunk will carry a landing motor and sufficient UDMH and NTO for Mars landing in addition to mid-course corrections, along with extensible landing legs The ISS will be the point of Earth Departure, and also Earth Return. I'm with GW on using a hydrazine-based fuel along with dinitrogen tetroxide oxidizer for all long-term deep space applications. NO restart difficulties, as this combination is hypergolic.

Dook · 2017-04-16 12:38:45

The Red Dragon 2 can get one ton to Mars. That's great for a tiny little re-supply mission.

What is the Falcon Heavy going to deliver to Mars? A tuna can. It may not be exactly the size and shape and layout that Zubrin planned but it will be a tuna can just the same.

What is the SLS going to deliver to Mars? A tuna can.

Oldfart1939 · 2017-04-16 12:47:52

So--a tuna can by any other name is still a tuna can? ;-)

SpaceNut · 2017-04-16 15:26:32

Which is why the issue for once man lands as to be in something not labeled a tuna can we will need to construct the permanent habitat space to create a domed structure around the lander as one senerio with the other being a previously landed unmanned inflatable to allow for the additional space to spread our wings in.

Sure the Space X Red Dragon landing is just the first of landing that are demonstrators for getting man to mars with another being a scaled up version that will not only target greater down mass but look at ways to get a unit back to orbit with switching fuel types unless we find a way to control cryrogenic oxygen from loss.

So how far do we need to push the 2020 demostrator mission that Oldfart1939 proposed in the second posting?

As we will be limited to what power can we provide as the issue for just the simple Oxygen and Methane creation systems, the down mass maximum of 2mT, the source of hydrogen and a qualification time period to say yay or nay to what has been accomplished as well to the quantity and purity of what we create....

The next stage demonstrator for larger mass and for a crew sized oxygen plus fuel creation for a return to orbit craft must be tried such as in

RobertDyck wrote:

ISPP for Mars Direct was supposed to do that. It included an SP-100 nuclear reactor, which was about the mass of a truck engine. Today we would use SAFE-400 which does the same job but is substantially lighter. But it was able to produce enough propellant to fuel an ERV in several months. That's months to produce fuel and oxidiser for this...
or this...

One part to solve is for the reactor as it needs to drop free from the part that is launched back to orbit as its not required nor are the radiators used to keep the reactor cool while in operation.

Oldfart1939 · 2017-04-16 20:22:18

SpaceNut-

At the time the original Mars Direct was formulated, we didn't have ISS up and running in it's present capabilities, nor were we prepared to do orbital assembly or reconfiguration of space vehicles. The other limitation was cost of throwaway launch vehicles. My model suggests orbital coupling of separately launched manned habitat, and a fully fueled TMI booster. Where we're kinda stuck is in the Earth return stage; how we accomplish that depends on the experimental efficiency of the Moxie units and subsequent LOX production and storage. Ditto the production of Methane via the Sabatier reaction. NASA seems to believe in having a fully fueled ERV orbiting Mars, and the Mars Ascent Vehicle only flies up and carries out an in orbit rendezvous with the ERV. That seems to be the one option, but if enough fuel/oxidizer can be made through ISPP, maybe that complexity can be skipped through.

In my view, having a fully fueled ERV is attractive, but requires we shift over to hydrazine type fuels and NTO. Another advantage of Hydrazine is it's very good Isp, and corresponding Id. It actually beats Methane in Id, with just a bit lower Isp. Keeping the empty mass at a minimum affords many advantages. I somehow can't figure a ERV fueled with methane/LOX will be stable in Mars orbit for 18 months; or longer. On the other hand, a stage using MMH or UDMH plus NTO can be kept liquid through some strategically located isotope decay heaters in and around the fuel tankage.

I realize that I've started several similarly themed threads, but we really need to use all our advantages gained in the intervening 27 years since mars Direct was postulated. My most recent calculations indicate that moving on from LOX/RP- in Musk's Falcon boosters as incorporated in Falcon Heavy could get a decent performance boost of ~ 7% by switching to MMH-Hydrazine and LOX is possible. This could allow the EDS to throw more mass than we've previously calculated.

SpaceX should also consider scaling up the Dragon capsule to make it (1) taller, and (2) increase the base diameter to 5 meters. The extended trunk could accommodate up to seven, but a crew of 5 would seem more adequate utilization of space and supplies for the Hohmann transfer trajectory to Mars orbit. Once before I calculated this to be in the 22 metric Tonne empty mass category, and fully fueled could carry 30 metric Tonnes of hypergolic fuels. It could be flown unmanned to and docked with the ISS through the docking hatch atop the Dragon Heavy vehicle. This is--yes, a different shaped "tuna can." We couple this while docked with a fully hypergolic fueled booster massing 63 metric Tonnes. This fuel could, in principle, be used in part to assist the Earth departure and still have enough to execute mid course corrections, enter Mars orbit, and carry out the Mars landing. This could be flown experimentally in my 2024 mission, or as a cargo carrier as early as 2022.

One thing that I'm holding invariant is the absolute need to get it done in the time frame of two terms of a favorable political administration. Any longer and we lose all impetus, in addition to the political will to do the mission.

SpaceNut · 2017-04-16 21:20:43

I think the best options are to leave the erv parked in mars orbit with MMH or UDMH plus NTO fuels to wait for a return trip as launching the erv from the surface using methane lox for a complete trip means launching with the water mass and other recycling plus food from the mars surface. Plus as a lander with the greater downmass we may not be able to achieve that much going to the surface.

The smaller return to orbit ship can be made reuseable from orbit by the returning erv having a supply to make it possible for the unit to return to the surface and be refuel via ISPP. This will require the least amount of fuel to relaunch as we are not lifting the oxygen or water to be consumed on the way back to earth for the crew as its already waiting in orbit.

Once the ERV is back in earth orbit the unit is either refuel from earth via fuel transfer or new stages are sent up plus new consumables in food for outward and return trip, oxygen and water to which it should be a simple topping off for water and oxygen to start the new journey to mars. Food and water plus supplemental oxygen can be sent to mars surface to resupply as needed via another transport lander system.

SpaceNut · 2017-04-16 21:34:59

Dook post #5 and Louis post #6 I think simular topic titles with each seperately titled would be the way to go to keep mission specifics from crossing from those not in the inital posts for the timeline that you each has proposed.

If that is your wishes we will make it happen other wise I am not entertaining talking specifics within this current evolving topic for Oldfart1939 of those other timelines to which I think would be also productive to do.....

You then could borrow from my posts to aid in you own topics plus any other input to help with those timelines by other members....

kbd512 · 2017-04-16 22:59:42

Oldfart1939,

My Mars exploration mission architecture has been discussed at length in other threads in this forum, but it's based on reusable Falcon Heavy rockets, storable chemical propellant ascent and kick stages, and Cygnus modules carrying a pair of crew members. The mission architecture mass is divided into roughly three equal masses for every pair of astronauts sent to Mars using individual Falcon Heavy rockets. No orbital assembly is required. Two launches occur during the first opportunity to transfer the Mars Ascent and Earth Return stages to Mars. One additional launch occurs during the second opportunity to transfer the astronauts to Mars aboard the Cygnus spacecraft. One additional launch can be added during the second opportunity to deliver additional consumables that provide the astronauts with more food / water / spare parts in the event that the astronauts are unable to ascend to LMO after their 500 day nominal surface stay.

This would bring the total launch costs to $260M per pair of astronauts, assuming each Falcon Heavy is reused once before a given departure window opens. While second launch reusability has been demonstrated, third launch reusability has not. I estimate that the total cost of the mission hardware will bring the cost to send a pair of astronauts to approximately $500M. If NASA wants to mount an exploration campaign to send six astronauts at every launch opportunity, then the cost is $1.5B per year, or roughly what three STS missions cost. I presume ESA and ROSCOSMOS astronauts will want to go, so it may cost as little as $500M per year if the crew includes 2 Americans or Canadians, 2 Europeans, and 2 Russians. Apart from the US Air Force, the major space agencies are the only real customers for Falcon Heavy. There's little likelihood that launch services costs will drop below about $260M per year per pair of astronauts unless Falcon Heavy is reused for all four launches.

The Cygnus has a HIAD attached to the base end (relative to its landing attitude on Mars) and a HAN monopropellant thruster module atop Cygnus (relative to its landing attitude on Mars) on the other end of the module. The Cygnus modules tether off to the expended Falcon upper stages to provide artificial gravity for the six month trip to Mars. The HIAD aerobrakes the Cygnus modules into the Martian atmosphere and provides enough deceleration to permit the HAN monopropellant thruster to soft land the Cygnus modules using four extendable wheeled landing gear containing electric hub motors for motive power on the surface of Mars. The extendable landing gear permits the Cygnus modules to be mounted atop ascent stages near the Cygnus landing area for return to LMO. The storable chemical propellant ascent stages landed during the previous launch opportunity rocket the Cygnus modules back to LMO to dock with the Earth Return stages for TEI and later, EOI and docking at ISS.

Cygnus is assumed to use 3 OGS, 3 CAMRAS CO2 scrubbers, 3 ionomer membrane water processors, 4 ATK MegaFlex solar panels for electrical power, and 250Wh/kg lithium-ion batteries for life support and power. All of the power and life support systems are current generation technology in the final stages of testing. Water and oxygen recycling is required, but these current generation systems are enabling technologies that are compact, light weight, reliable, and consume substantially less electrical power than legacy ISS systems. Avionics are assumed to be a derivative of the avionics Cygnus currently uses. Communications are assumed to be UHF and SHF systems based upon the systems that Curiosity uses.

More technical details are available in other posts in this forum.

louis · 2017-04-17 06:49:48

I hadn't come across this document before.

It shows serious attention is being given to Chryse Planitia as a landing area for humans, which is what I propose for my hypothetical H2Mars mission architecture. So I was glad to find it!

https://www.hou.usra.edu/meetings/explo … f/1019.pdf

Oldfart1939 · 2017-04-17 14:31:37

OK, I found my original sheet of calculations, now rendered obsolete by SpaceX; the upgraded Falcon Heavy can now deliver 63,000 kg to LEO. This is composed of the following components: Upgraded Dragon 2 capsule with seats for 5 astronauts; 7000 kg. Extended and enlarged trunk stage, now integral with the capsule for crew accommodation; 14,000kg. This includes a crew in transit, water supply and 4760 kg of food. Also included is a water collection/reprocessing system and air purification devices. calculates to 2800 kg Oxygen which will be augmented through a small Moxie unit recycling exhaled CO2 from crew and dumping the CO by-product. Total crew weight is 440kg.In the storage area we can haul an additional 4000 kg of food and 2000 kg of personal clothing, protective gear and some science instruments. Calculated 6000 kg for structure and accommodations (sanitary facilities, some exercise equipment, bunks, comm equipment, etc.). This leaves 42,000 kg for the Mars landing engines, fuel, and landing legs. Rounding down to 38,000 for onboard UDMH and NTO, 4,000 can be distributed between spacecraft structure and additional equipment.

Mated to this vehicle at the ISS will be a TMI booster stage powered by UDMH and LOX. Available mass is net: 63,000 kg, of which 6,000 kg will be hardware. Depending on the flight trajectory and flight time (I calculated 200 days of food, plus a 40% margin for error), we need an absolute minimum delta V of 3.4 km/second. The 200 day transit requires closer to 3.6 km/second. This initial booster gets us a delta V of 1.15 km/second. The fuel onboard the spacecraft itself is sufficient-plus to get us to Mars with a reserve for propulsive landing. We can fudge-factor some of the payload down, if necessary for a safe(r) landing reserve. This is all a crude calculation based on the Rocket equation, and as a 2 stage departure. It could be given a larger margin of error through use of some SRBs during the first boost from LEO.

What this all accomplishes is getting a crew of 5 on Mars, with an onboard supply of food for an additional 250 days. Mission success depends on prepositioned ERV and additional food, with associated habitat and equipment.

Last edited by Oldfart1939 (2017-04-17 14:35:14)

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