Mars 9 tons at a time.

[j05h]

Crew and suit mass are a major driver. My suggestion is twofold. First, use existing suits for launch, in-space and descent. My current choice would be the Sokol suit, especially with any Soyuz derived capsules. Second, suits for use on Mars should be Mechanical Counter-Pressure (MCP) suits designed for servicing, wearability and ruggedness. Mars suits should be repairable at the base and field-patchable. They should be rechargable like SCUBA hardware - plug into your rover or toolbox and it recharges your suit air and power. Separate suits (and I'd use separate space suits for each space segment) keeps dust to a minimum, also using a fresh suit means you aren't getting broken/worn equipment when you need reliability.<br /><br />If suits are properly storable, they can be cached on the surface as part of the forward-preparation before crew arrival.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[j05h]

Lets cover areobraking and EDL hardware. The main question with Mars Lite is how to reduce the absolute mass of this hardware? Every pound of EDL hardware is a pound away from payload. Are new materials better? Can current metal or phenolic heat shields be made light enough to work? <br /><br />If EDL/aerobrake hardware is 1/2 the mass of the craft, it is probably not going to work. If it can be reduced to 10% of the payload mass, we're golden. Instead of a Mars Pathfinder-style backshell and dropped cruise stage, I'd like to see everything integrated into a single unit. The extra parts (pumps, RCS, tankage) can be repurposed on the surface if designed properly. Also, what do you all think of using the same basic design for all outbound craft? Crew capsule and cargo pods would, like Soyuz and Progress, come from the same production line. It seems like it would make crew servicing simpler (you always know what you are sticking you arm/head into) and allow much redundancy (you can use cargo pods as sleeping quarters, etc at the growing base). <br /><br />If possible, the same setup should allow for direct entry (or 2-pass aerobrake) to Mars surface and gradual circularization for entering useful orbits. <br /><br />Thoughts on Aerobraking procedures and EDL hardware? How to reduce that mass as much as possible? <br /><br />Here are the MER numbers. Airbags are probably not tough enough to handle 9t package, and the delivered payload is low comparatively. What improvements can be made?<br /><br /> * Rover 185 kg<br /> * Lander 348 kg<br /> * Backshell / Parachute 209 kg<br /> * Heat Shield 78 kg<br /> * Cruise Stage 193 kg<br /> * Propellant 50 kg <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[j05h]

<i>> 40-60 flights a year would be minimal. You have to remember it is using the same First Stage as other payloads.</i><br /><br />Thank you so much for sticking with the topic, that is direct delivery via current launchers of Mars exploration hardware.<br /><br /><i>> I see the moon and Mars as well as asteroids and even Comets accessible in a very short time.</i><br /><br />I see that as well, but not by following the path you advocate. That path leads to endless development cycles using ancient hardware. We have better ways of doing things now. The type of system I'm describing is to leverage extant, actively improved, current rockets to start developing Mars now, not in 20-30 years. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

I found this wiki article on reentry useful, especially this part:<blockquote><font class="small">In reply to:</font><hr /><p>H. Julian Allen and A. J. Eggers, Jr. of the National Advisory Committee for Aeronautics (NACA) made the counterintuitive discovery in 1952 that a blunt shape (high drag) made the most effective heat shield. From simple engineering principles, Allen and Eggers showed that the heat load experienced by an entry vehicle was inversely proportional to the drag coefficient, i.e. the greater the drag, the less the heat load.<p><hr /></p></p></blockquote>So going with the inflatable (or at least expandable) shell you could get a lot more braking at lower temperatures. After all, you can't take months to circularize like the current orbiter did, if you have people on board. With the unmanned cargo shipments you can afford to be less aggressive but there is something to be said for usng common parts. Ideally the shell material can be recovered later and used for constructing shelters.<br /><br />Some of the first few things to send in the 9 ton shipments, cribbed from the Blue Mars series of books:<br /><br />1. Self-cleaning, self-erecting solar power stations, with vibration, or brushes, or something to knock the dust off. With batteries in the base and a plug on the outside. Panels track the sun to improve efficiency and reduce dust accumulation. Folds down in high wind. The books used a nuclear power plant, which had to be assembled on the ground from multiple shipments.<br /><br />2. A bulldozer with back-hoe, with electric drive recharged from above power station, for excavating below-ground living quarters (for radiation and temperature shielding). With both on-board and remote control possible. Doesn't have to be controllable from Earth, but at least from inside a shelter. <br /><br />3. Drilling equipment, to look for water. Same power and control features as the bulldozer.

 

[scottb50]

The type of system I'm describing is to leverage extant, actively improved, current rockets to start developing Mars now, not in 20-30 years.<br /><br />I think if you build on existing technology, with evolutionary upgrades the time frame would be similar to the Falcon9. Main structure consists of the same two parts used repeatedly. Modification to the RS-68 and RL-60 would be the major changes, remove the turbo-pumps from both and add cooled nozzles to the RS-68.<br /><br />I don't see it as endless development cycles, just one; the basic Module. Once you have a Module you attach them together in various numbers and configurations for different needs. Sure the hardware will be upgraded but as long as it is designed for retrofit to Modules it will be evolutionarry change. What you advocate is distinctly different moon and Mars hardware, what I advocate is the same hardware used in different manners. <div class="Discussion_UserSignature"> </div>

 

[j05h]

<i>> "made the counterintuitive discovery in 1952 that a blunt shape (high drag) made the most effective heat shield...."<br /><br />So going with the inflatable (or at least expandable) shell you could get a lot more braking at lower temperatures. After all, you can't take months to circularize like the current orbiter did, if you have people on board. With the unmanned cargo shipments you can afford to be less aggressive but there is something to be said for usng common parts. Ideally the shell material can be recovered later and used for constructing shelters. </i><br /><br />The two methods that seem most useful are direct-entry or some kind of multi-pass aerobraking. If it can be done with a couple of passes (2-5?) then it would allow more precise landing ellipsis and easier access to various orbits. I'd rather have common hardware that can do both - ie. it can do a hi-G direct entry or aerobrake. What's worse for a crew: a week of several gradual braking passes or one crushing decent? The system should allow crew and cargo access to all of Cis-Mars space if possible.<br /><br />On re-using aeroshells - if the system is derived from current capsule (Soyuz esp.), it is an easy enough matter to dock them to a node unit. Used descent capsules could be cleaned out and serve as general volume for the crew. The biggest problem I see with a common-capsule approach is the problem of landing larger hardware - it's hard to drive a bulldozer through a 1m docking hatch! <br /><br />This point to two types of lander, or a different solution than a big Soyuz or Dragon. The first lander is a crew/pressurized-cargo capsule and the second is an equipment lander that can handle full-size vehicles. This second lander might be an aeroshell/backshell with small landing rockets in a frame or on the vehicle itself (James Cameron Reference Mission). Essentially, any large work seems to require some kind of roll-off capability for equipment.<br /><br />With the crew and pressurized capsules, <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[j05h]

<i>> I don't see it as endless development cycles, just one; the basic Module. </i><br /><br />That's fine but has nothing to do with the subject. <br /><br /><i>> What you advocate is distinctly different moon and Mars hardware, what I advocate is the same hardware used in different manners.</i><br /><br />yes, it is a very different approach. Instead of waiting for that next, next rocket engine, it is a proposal to start now, using existing rockets in roughly existing configurations. If a payload was available now, we could start now - unlike every other proposed Mars mission. If you want to talk about endless development of the Next Big Thing, please start another thread. Please add something to the discussion of flying Mars missions in small, direct-throw packages. <br /><br />Please focus on payloads and what to do on Mars, not the launch. Start your thinking after TMI, so to speak.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

Interchangeable heads for the back-hoe part.<br /><br />Whether the dozer has a cord or not depends on the energy storage options in the dozer itself. It takes a lot of energy to dig big holes. If plenty of water is available then H2 + O2 could be used, though rather explosive. Batteries are heavy to ship there and have problems with low temperatures. Perhaps some development in lo-temp batteries could expand the options here. Flywheels have none of those problems, assuming modern lightweight super-high-speed flywheels (energy stored is linear with mass but goes up as the square of speed).<br /><br />Good point about connecting the power stations. Try to land the first ones close together. Configuration depends on latitude. If going for the poles to get easy water you need a more vertical sail-like deployment. Might want to do that for the first missions until deep water can be located though it makes the temp problem worse. Less sunlight hours too. If deep water can be detected from orbit before we send all this stuff, then I'd go for a more equatorial first base to minimize the cold and dark.<br /><br />I think two lander types are required as you say. A roll-off palletized type for big cargo and something else for people. All have to fit the same launcher and should use the same aerobrake/reentry technology, as they are all going to be in the same weight range.<br /><br />The dozer may have to fold up somehow to fit in the launch shroud. The trick is it needs to be pretty strongly built. We aren't talking Spirit/Opportunity surface scratching here, but 20 foot deep trenches that get roofed over and backfilled. Maybe little dozers at first then a big one later with better vehicle development. Have to watch our for chemically-corrosive surface dust.

 

[j05h]

some links for current dozers and skid steers:<br /><br />http://www.cat.com/cda/layout?m=138561&x=7<br /><br />check out the pc-138usld-8 with blade and arm, plus others:<br /><br />http://www.komatsuamerica.com/<br /><br />something like the PC35MR-2 is about half the "9 tons" mass - it has a 10' digging capacity. Several of the Komatsu units already fold compactly. An electric/flywheel/fuelcell powered unit with several attachments would be reasonable within this range. Caterpillar makes very large electric earth-movers and has a fuel cell page in their "Generators" section. <br /><br />Caterpillar expressed interest years ago in nuclear moon-dozers, so this must be a direction that they still at least glance at. Call it the "Hilton Effect" - a lot of big business knows "Space" can produce but there is no current entry point for their products.<br /><br />One fuel option that Zubrin discusses is "silane" which is processed from methane and something. He says it would burn like gasoline in a modified internal combustion engine using CO2 - allowing the whole range of Earth vehicles including aircraft on Mars. It seems more complex in some ways than methane+fuelcells.<br /><br />At typical aerospace costs, a methane fuel cell, even a prototype, from Ballard is completely affordable. The ISRU processing hardware is small enough that it could be part of the cell's tankage.<br /><br /><i>> Good point about connecting the power stations. Try to land the first ones close together. </i> <br /><br />Here are three thinking points about module mobility. Dragging is easier if the heatshield is still attached. ATHLETE is a viable option for all sorts of uses. A bell-shaped pressurized capsule is fairly easy to drag in either orientation. <br /><br />If the architecture requires dragging habitable modules together, maybe it makes sense to use the same tools <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

Woo this is fun.<br /><br />I would like to see some investigation of the large inflatable aeroshell instead of hard heat shields. For one thing it reduces the risk of dropping hard things on the people below.<br /><br />I know Bigelow doesn't like the idea of dragging modules around and trying to align them on rough terrain, which is why he is going for orbital assembly. But that is a lot easier to do on the moon than Mars. Dragging also could damage stuff - the surface or Mars looks pretty abrasive - and how far might you need to go? 100 km? How about something like bicycle wheels or what the old lunar rover had, and the things get towed into place by the dozers? A trailer like thing you could lift a capsule onto and move it, so everything doesn't need its own wheels, just to be moved once?<br /><br />An advantage of getting the dozer there first is site prep. Make a level place to begin with, get rid of the rocks, sunk into the ground as far as you can for shielding, then put the modules in the trench and cover with the dirt you dug out in the first place. Once the underground hab is ready the people can move out of the small capsules they arrived in. Need some data on angle-of-repose of Martian dirt in .3 G. I am not a civil engineer. Anyway, don't need to make the ultimate Martian city the first time, but provide incrementally better accommodations as you go.<br /><br />Some chemical research needed to figure how to make concrete out of Martian stuff. This could help in making the larger undergound habitats later. And save all that aeroshell stuff - might be able to use it for linings.<br /><br />I wonder how far down the water table is? Don't want a wet basement. But then having the well inside the house has a certain convenience.<br /><br />Add water treatment plant to deal with the dirty ice. Might be some unpleasant gasses dissolved in it.<br /><br />A pressurized capsule would not be my first pick for the power stations. The mass overhead of the uneeded

 

[gunsandrockets]

<I would like to see some investigation of the large inflatable aeroshell instead of hard heat shields.><br /><br />IRDT -- Inflatable Reentry Descent Technology<br /><br />Russian concept I believe originally intended for Mars mission applications. See links...<br /><br />http://www.astronautix.com/craft/irdt.htm<br /><br />http://www.space.com/businesstechnology/technology/051012_irdt.html

 

[gunsandrockets]

<Jim- How much modification would be required...?><br /><br />jimfromnsf won't be responding for a while.<br /><br />http://uplink.space.com/showthreaded.php?Cat=&Board=suggestions&Number=347645&page=0&view=collapsed&sb=5&o=0&vc=1<br /><br />"7/11/07 - user jimfromnsf given a one week suspension because of repeated violations of the UPG"<br /><br />

 

[j05h]

<i>> <Jim- How much modification would be required...?><br /> /> jimfromnsf won't be responding for a while. </i><br /><br />No, he answered already. Bummer about him taking a little break. <br /><br />Guns- any thoughts on Mars at 9t per launch? The plan is to follow Zubrin's best advice by placing payload directly TMI and directly onto the surface, just in small, available packages.<br /><br />josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[gunsandrockets]

< any thoughts on Mars at 9t per launch? ><br /><br />Okay for cargo support, inadequate for a manned vehicle.<br /><br /><The plan is to follow Zubrin's best advice by placing payload directly TMI and directly onto the surface. /><br /><br />The 4 man sized Zubrin Mars Direct plan was probably a little too optimistic within the limits of a Saturn V payload. But I think something like Mars Direct but with a 2 or 3 man crew might be possible while only using Delta IV rocket boosters instead of a Saturn V. I outlined the basics in my earlier post...<br /><br />You can gain something close to the performance of a Saturn V by using Solar Thermal Propulsion for LEO departure in addition to using Earth Orbital Rendezvous to mate the payloads of two Delta IV heavies at LEO.<br /><br />One nice thing about EOR is that if anything goes wrong the chance of loss of crew is minimized since abort to Earth is easy.<br /><br />Note: when I refer to the Delta IV heavy I mean the configuration of the Delta IV that has already flown which uses three common core boosters, not some hypothetical future growth version of the Delta IV. Using the word 'heavy' can sometimes be confusing and lead some people to think about Heavy Lift Vehicles (HLV) such as the Saturn V or the Ares V.

 

[MeteorWayne]

Actually wouldn't surprise me if he takes his marbles, goes home, and fails to come back.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[thereiwas]

It appears that normal concrete (using calcium silicate cement) may degrade rapidly in a CO2 atmosphere. Link to paper. May need something else.

 

[j05h]

<i>> Okay for cargo support, inadequate for a manned vehicle. </i><br /><br />It's about the full mass of an upcoming Dragon. With only 2-4 crew and the possibility of docking with a light Sundancer, you still don't think it would work for crew? I'm looking for a solution that does allow crew. What about a separate transfer vehicle and lander, serviced at a small Mars orbital complex, made of the same capsules and nodes?<br /><br />My three reasons for starting with Delta are it's current availability, the slack in their production line (offering to buy several dozen DIV-H might get you a serious deal) and the known cost - about $250M per launch for the Air Force.<br /><br /><i>> You can gain something close to the performance of a Saturn V by using Solar Thermal Propulsion for LEO departure in addition to using Earth Orbital Rendezvous to mate the payloads of two Delta IV heavies at LEO. </i><br /><br />Two "Mars Lite" landers (same # of rockets as you suggest) delivers no more than 18t total to Mars' surface. So you are saying a solar-thermal rocket (STR) as part of a 50t mission mass in LEO would deliver something like 30-40t to the surface of Mars? <br /><br /><i>> One nice thing about EOR is that if anything goes wrong the chance of loss of crew is minimized since abort to Earth is easy. </i><br /><br />Very true. My solution, using the direct-throw concept, mimics T/Space's "flotilla" concept for Lunar missions. Each launch opportunity to Mars would see a surge-launch of as many Mars capsules as possible. If something is wrong with your capsule, their is another independent vehicle nearby. Abandoning ship should be an option. <br /><br /><i>>Note: when I refer to the Delta IV heavy I mean the configuration of the Delta IV that has already flown which uses three common core boosters,... sometimes be confusing and lead some people to think about Heavy Lift Vehicles (HLV)....</i><br /><br />Yes. We're discussing the flown Delta-IV Heavy, 17,600lbs to TMI. It's also g <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

What is the Atlas V throw weight to TMI? (And where are you getting these figures?)<br /><br />Wikipedia has this to say about the Delta IV: "In 2003, Boeing pulled the Delta IV from the commercial market, citing low demand and high costs. In 2005, Boeing stated that it may return the Delta IV to commercial service; however as of 2006 no further announcements have been made regarding this. All but one of the first launches have been paid for by the U.S. Government, with a cost of between $140 million and $170 million." <br /><br />Apparently the cost for a Delta launch is about 30% higher than its rivals in the commercial launch market, so they are staying with the USAF and NASA business where it seems price is not a concern....<br /><br />Is Ariane 5 of any use for Mars? I notice that it was originally designed to be man-rated.

 

[j05h]

17,600 or 17,650 are both from Boeing's website, other figures and backup are from Astronautix.com and wikipedia.<br /><br />My suggestion for Delta IV, as above, is US availability, slack demand compared to production capacity and known price. You forgot the added part from wiki where the AF is quoted as saying D IV is $250M currently. As with a lot space discussion, volume and frequency would drive that price way down. <br /><br />Delta IV H as currently configured can throw 17,650 lbs or 8000kg to 10km/sec at 27degree inclination for TMI, describing it as "C3" which I'm pretty sure is "escape velocity 3" or "solar orbit 3". So I guess the subject should really be "9 short tons at time". This PDF press kit has the chart:<br /><br />http://www.boeing.com/defense-space/space/delta/kits/d310_d4heavy_demo.pdf<br /><br />Atlas numbers are somewhat lower (maybe 2.5-3t TMI?) but I can't find a convenient chart. Ariane 5 is 10,500 kg to GTO, so something less than that TMI. The real vehicle to plan for would be Falcon 9, since Elon Musk has publicly said he wants to fly people to Mars. Falcon 9 is about 5t to GTO, so maybe 2-4t TMI? They claim a $90M flight for 28Mt to LEO. That's a price that others can turn a profit with, and they claim it'll be available in 2010.<br /><br />Edit: deleted the extra long link.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

The F9 data sheet (PDF here) describes "C3" as "Escape Energy" and it has units of km^2/sec^2. I am not clear on what that means.<br /><br />That 28Mt to LEO you quote is for the F9 Heavy, not the regular F9. F9 Lite seems to get 10Mt to LEO.

 

[j05h]

c3 = "Escape Energy". Thanks, that makes sense. It must be a general measure of velocity for escaping earth's gravity. Km^2/sec^2 is a measure of acceleration over time, literally it is a measure of counter-acting gravity. <br /><br />Thanks for F9 correction.<br /><br />Concrete on Mars can be solved fairly easily: Use sandbags and barbed wire, mixing sand with a little water. Build igloo, dome and barrel vault per Nadir Khalili's "super-adobe". There must be an equivalent of concrete for Mars besides frozen sand. Maybe something with sulfates, like at the rover sites? <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[jimfromnsf]

C3= characteristic energy<br /><br />Km^2/sec^2 is not an acceleration but velocity squared.<br /><br />Characteristic energy is computed as:<br /><br /> C3=v infinity squared<br /><br />where<br /><br /> v infinity, is the orbital velocity when the orbital distance tends to infinity. <br /><br />For a spacecraft that is leaving a planet on a parabolic trajectory:<br /><br /> C3=0<br /> Hyperbolic trajectory<br /><br />For a spacecraft that is leaving a planet on a hyperbolic trajectory:<br /><br /> C3=mu/a<br />where:<br /><br /> mu is the standard gravitational parameter,<br /><br /> a is the length of semi-major axis of the orbit's hyperbola.<br /><br /><br />

 

[nyarlathotep]

<i>Concrete on Mars can be solved fairly easily: Use sandbags and barbed wire, mixing sand with a little water.</i><br /><br />Why can't we just build wood cabins? We've known that there has been vegetation there since Lambert discovered it in the 1800's.

 

[j05h]

Ny - you show me a real Martian tree and I'll show you the lumbermill for it. <br /><br />"Superadobe" sandbag domes are a proven technology, check out CalEarth.org for some mind-blowing architecture. <br /><br />For a "Mars Lite" schema, being able to just bring sandbags and wire (or recycle metals) and using those basic materials to build shelters would be a huge leverage. 6 tons of empty sandbags can build a lot of domes. I'd recommend that a "base builder" rover or larger Dozer be equipped with sandbagging hardware. <br /><br />j <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[thereiwas]

Those adobe domes look like something right off of Tatooine. I wonder about ability to withstand earthquakes.<br /><br />What I am concerned about in your idea to just mix water with the dirt to freeze it, is if the bags are not vapor tight the ice will sublimate away, leaving you with bags of loose sand and nothing to retain the shape.<br /><br />I am looking for something with which to line the walls, ceilings, and floors of completely underground dwellings, to prevent cave-ins and air loss.<br /><br />Try to dig a hole in loose sand with vertical sides - can't be done. I think the soil on Mars is likely to be very dessicated for several feet down.