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The only thing I can state at this point in time--the asteroid retrieval mission strikes me more as a "make-workee" program in order to justify the enormously expensive SLS. This smacks of a Bush-II Constellation project technology rescue mission. I don't have any enthusiasm for it, and it's burning through lots of scarce NASA cash. The SLS should be utilized a couple times for a Apollo 8 Redux, and then quietly retired.
There really isn't much of a scientific payback for asteroid retrieval.
The stoichiometric ratio of O2 and CH4 is a ratio of 64 to 16 in mass. CH4 + 2 O2 ----> CO2 + 2 H2O. If less oxygen is used there will be carbon monoxide formed, CO. There is also as a consequence, some deposition of carbon, or coking. I haven't seen the fuel/oxidizer ratio for either RP-1 or CH4 in the Merlin 1D+ engine versus the new Raptor.
I believe the Red Dragon 2 that Musk is thinking of for his first Mars landing is fuelled by a Hydrazine/NTO couple. Not sure whether they are using UDMH or not, or possibly MMH?
My understanding of this problem may be somewhat different from the straight aerospace/rocket motor engineer, and as a chemist have a slightly different "take" on things. Use of RP-1 requires an extremely high LOX ratio to RP-1, greater than the stoichiometry would indicate in order to avoid the coking problem. Switching to CH4 should allow getting the ratio back closer to the "as written" chemical reaction, thus lowering the amount of surplus oxygen the vehicle needs carry. I've heard numbers bandied about by SpaceX regarding the actual "observable" Isp for the vacuum engine using CH4 as 382 seconds. On the other hand, reported numbers, again "observed" for RP-1 as being around 300 seconds.
Another advantage of CH4 is the extremely low Melting Point (not actually "freezing point") of -182.48 C, and a Boiling Point of -161.49 C. As a result, methane is extremely pure and free from contaminants which are usually present even in highly refined kerosene (RP-1). The density was also given, but the temperature at which listed was absent. d = 0.4, roughly half that of RP-1. As usual, a tradeoff game the constructors will decide...
Figures for CH4 are from the Handbook of Chemistry and Physics, 48th Ed.
Methane fuel means a heavier rocket for launching....
On what basis is this comment made? The tankage for CH4 should be approximately similar in construction to the LOX tanks on a Falcon 9, and I'd assume a supercooled CH4 for densification. Methane has a lot higher Isp than RP-1, which should offset any weight disadvantages. Maybe GW Johnson can jump in here to clarify?
I've quoted Zubrin's Book "Entering Space" several times, wherein he states that the biggest commodity the "major contractors" are selling in the cost-plus contracts is OVERHEAD! These herds of people simply milling around add to the COST side of the equation, and the profit is in the PLUS!
SpaceNut-
Agreed re: NASA building cost-plus contract rockets!
The world's best manufacturer of a Borosilicate-type glass Is Schott, based in Germany. Not sure they still build some of the apparatus they once did, but my chemical plant had all glass chemical reactor systems up to 200 liters capacity, all constructed from their own glass. I'm thinking their brand name was "Duran?"
Upon checking at www.us.schott.com the new glass they are offering for use in oven doors, and for chemical applications is called "Borofloat."
I'm not wishing this to become a politically driven thread, but just an above-board discussion about how we are going to make progress towards the goal of landing men on Mars in the next 8-12 years. I have no enthusiasm for the ULA SLS system, as it was designed and built without a real end use in mind, but only as a political expediency to avoid throwing away all of the Bush project Constellation research and development monies.
I'm just going to state my personal view here and then let others chime in and see whether a consensus emerges. NASA has essentially lost it's sense of it's original goal, which under Kennedy was getting man to the moon. Now, the money they're allocated is in my mind, being frittered away on a wide ranging and potentially pointless (at least at this point in time) endeavors. I'm fully on-board with Dr. Zubrin's "lets go to Mars NOW, using the technology we've had for nearly 40 years." Research on "impossible drives," solar electric drives, and Earth Sciences, all need to be massively scaled back--if not eliminated outright. The Asteriod Redirect/Retrieval mission doesn't really get us very far out of LEO--or even as far from Earth as a back to the moon program would. I would much more prefer that NASA start doling out more $$$ to various contractors, such as SpaceX, Boeing, and Lockheed-Martin for some interlocking projects that would advance human spaceflight activities.
Dr. Zubrin, in his book "Entering Space," suggests some "prizes," or awards for achievements; NASA could earmark funds as rewards for accomplishment of certain milestones along the way. So far we haven't ever flown a working Nuclear reactor in space, and that's something we need on the surface of Mars. If we ever hope to really accomplish anything w/r exploration and study of Europa, we'll need that power. Solar just doesn't cut the mustard in the outer solar system. Get some funding for methods of long term cryogenic storage of animal embryos, eggs, and other agricultural sources for potential colonization.
From all my readings, the Falcon Heavy at ~ $98 Million per launch is a huge bargain when compared to the SLS. Just "wondering out loud," as to whether SpaceX will develop a new heavier-still version rocket, performance of which, exceeds the basic Falcon design by using CH4/LOX propellants and the new Raptor engines? This would seem to be a logical developmental pathway, from the business end of things, to proceed. I know there are some numbers floating around, but haven't taken the time to track them down, about the performance of the Raptor engines as compared to the Merlin D engines. I recall the Isp for the vacuum version being stated by Musk as "approaching 383 seconds." I'm just offering a rational/logical pathway forward towards a first Mars manned mission by 2024. I just don't see the massive Colonial Transporter being brought to fruition that soon, but an intermediate Super Heavy "Pseudo-Falcon" could be...
Contact of LOX with carbon fiber has already been discussed in the SpaceX 1 September "anomaly." I'm very skeptical of this approach unless a PTFE-type polymer lines the tank.
One way of accomplishing the laboratory is by sending a completely equipped Lab Hab. As a separate vehicle launch, which could also haul a partial load of supplies.
As I was trying to post before just how much more science do we really need other than site selection before landing to stay so we can do more science for the other things not related to survival.
My reason for starting this thread was for a laboratory doing basic science, as well as supporting planetary development. Not making bricks, small metal parts, etc. This means looking for evidence of life, ability to identify geologic specimens, assist in procuring a source of potable water, etc.
Small metal items are best produced through 3-D printing. Smelting requires a source of carbon monoxide, normally provide by coke. This could also be provided by the oxygen producing reaction from carbon dioxide.
I suspect that the first rovers will be shipped complete from Earth, that way they can be made from appropriate materials. I also would venture to say they'll be pretty small and have limited seating capacity, on the order of a Polaris Ranger; maybe 2 or maximally 4 seats. All of the enclosure could be of carbon fiber reinforced polymer (type to be determined) but all the running gear (engine or electric motor, transmission, axles, etc.) will be metal. The ISS is mostly constructed from metals, so the scattered radiation from GCR is not really a big issue. On Mars, we'll be able to somewhat attenuate the exposure due to the atmosphere, but never eliminate entirely.
The needs are pretty self-evident: a good geologist/paleontologist, a chemist/biochemist with good analytical instrumentation skills; a second geologist/hydrologist/seismologist. Of the first dozen or so explorers sent, there should be a good core scientific team. The engineers are a given and some with good hands-on construction skills. But that's a different part of the mission.
Just looking at the photos returned by the rovers shows an enormous amount of layering caused by sedimentation. Turn a good paleontologist loose on those formations, and get the base laboratory working on them. Equipment is needed to split layers looking for fossil evidence, so one of the most essential instruments we should bring is a great microscope for sample examination, and in fact there should be a binocular "macroscope." In order to characterize samples, an FTIR spectrophotometer would be useful. According to a recent article, the "Surface of Mars is covered with organics." The FTIR would be able to identify such compounds. Some sort of chromatography for determining the composition of organic mixtures is essential; either HPLC or/and Gas chromatography. The ability to do mineralogy type assays is also essential. What is of immediate importance is finding water, so having the necessary reagents available for water analysis is of extreme importance. Determining whether or not water found is potable and what treatment would be needed to make it so is essential for colonization. Soil analysis is needed to establish what amendments are needed for greenhouse agriculture, so necessary reagents and associated instrumentation should be taken along. Chemistry is the core science in determining what's needed for residence on Mars.
One of the major reasons for making the epic journey to Mars is for the science, but what does that really entail? What sort of science should we/will we be doing, and what equipment and personnel are really required to accomplish the goals which are established? These are all questions which must realistically be asked well in advance of the first manned missions.
I would accurately guess that the search for evidence of life present and past is the foremost scientific reason to visit the Red Planet, and colonization is second. Having a properly equipped scientific laboratory is only one half of the equation, and the personnel manning it compose the other half.
So...what will the scientists be doing, and what sort should they be? Post comments, and I'll do so myself in a different post to this thread.
A possible material for a Mars rover construction is ABS. The properties can be varied through the amount of the butadiene rubber included in the formulation, but this is a "plastic" I've suggested this for a lot of Mars construction, also for an in situ manufacturing project.
I'd also suggest as does Robert Zubrin, thinking about using an internal combustion engine running on methane and oxygen. That would alleviate the battery hydrogen issue entirely.
The whole program is driven by the economics at the time. Instead of doing things by one-sies and two-sies, we actually send a larger number of the small supply ships in advance as well as the return vessel for one of the crews. Initial launches: 1 Habitat with basic science supplies + one supply only vessel, with consumables + ERV. Second set of launches: Another Habitat + one supply vessel with consumables + one supply vessel with construction equipment and greenhouse module + ERV. It really depends on the size of the first rockets used. If we're only looking at the Falcon Heavy upgrades, we could have only a crew of 4 initially and possibly a 5 person replacement-reinforcement crew. From the first crew of 4, we recruit 2 to stay and bring the base up to 7. A repeat on the next Hohmann transfer window and we have possibly 12 on Mars with 2-3 returning to Earth. We grow stepwise, with each transit opportunity increasing the base population and equipment on hand.
I cannot see doing a Flag and Footprints mission at all. 30 days isn't really enough time to accomplish any in-depth science. We also need time in order to do a wide search for accessible water supply.
What we need here is another thread discussion of the Mars Base -I, and the science lab and associated equipment; also discuss the types of scientists we'll need to get the most bang for the Gigabucks.
If one remembers that bacteria are PLANTS, and could have synthesized a crude chlorophyll-like pigment...respiration in a carbon dioxide atmosphere was thus possible. I believe elsewhere Robert alluded to a Bacterio-rhodopsin being a possibility, such as Halobacterium Holobium which still contains Bacterio-rhodopsin.
GW-
Just guessing here, but my bet is Musk will attempt doing something spectacular. It certainly won't be a manned Dragon 2 around the Moon, but something representing a major step forward. Also, it's ABOUT TIME someone embarrassed NASA; that agency has become hyper stodgy. Ditto the 2 major contractors whom I'll allow to remain nameless.
GW-
If only one government sponsored trip is made to Mars, the Zubrin/ Mars Direct 18 month stay is mandatory; not just the "flag and footprints."
To make scientific sense of things, we'll need to be extremely mobile while there. I see all the evidence of layered rocks and cannot help but wonder what fossils might be lurking there. The time frame in which Mars had water and warmth could possibly had Trilobites, Nautiloids, etc., and possibly some oxygen producing sea plants.
Lockheed-Martin and NASA have both become mired in their own inertial wells. There is really nothing motivating them anymore--just long term employment and of course...money. My WAG is SpaceX could do this for less than$200MM. The stated price of a Falcon Heavy launch (per SpaceX website) is $95MM.
Itchy feet coupled with insatiable curiosity. We really won't have our appetites whetted until we first set foot on the planet; we don't really know enough at this point to even ask the right questions, much less provide answers.
I for one, would be going for a multiplicity of reasons: my curiosity as a scientist, for the challenge, and most of all...for the adventure. I've been a high altitude mountaineer and rock climber all my adult life, and am something of an adrenaline junkie. I grew up reading "Rockets, Missiles, and Space Travel," by Willy Ley, the Collier's magazine articles by Wernher von Braun, et. al., etc. It was a sad day that Tricky Dick shut down the deep space goals for NASA in preference for an orbital delivery truck.
Dragon 2 would require some additional life support facilities/equipment. More onboard oxygen, water, food and some additional thermal insulation. The service module could carry all this and do a separation/180 reorientation/re-dock on the way and the ISS access hatch could allow utilization of that space for equipment/supplies, etc. The service module would also require pressurization.
This little jaunt around the moon could provide some excellent learning experience for SpaceX.
Atlas V doesn't have the ability to do this. Only Falcon Heavy.