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I remain somewhat skeptical of Musk's grandiose plans, especially the 100 passenger space ship. There definitely needs be some intermediate "proof of concept," and "pathfinder" vehicle as an intermediate step. The amount of food needed by 100 colonists is almost unimaginable when one does the calculations. As much as I'm a "fan" of Elon and SpaceX, he needs a hard dose of reality.
An intermediate vehicle capable of carrying 12 humans and a lot of food should be a first step, but the first several flights carrying crews of 7 and needed equipment. Maybe by the mid 2030's we could begin bringing larger numbers, but otherwise, proceed carefully and somewhat cautiously. Criticism of the Zubrin Mars Direct architecture is unfounded. Reusability is definitely a goal to pursue, but probably not in the first 2-3 Hohmann transfer opportunities after the hardware becomes available. A goal of first establishing a VIABLE human presence needs to be accomplished, followed by colonization. Not trying to be a wet blanket, but a rational and realistic critic. There's nothing wrong with 'Thinking Big," if tempered with a dose of reality.
These probes must also have adequate power for data transmission. An awful (wasteful) amount of the weight and volume is comprised by solar panels. TGIs are not enough. Small Nuclear Reactors are the wave of the future. It makes no sense at all to develop great instrumentation and then lack adequate power to return the data other than in driblets.
Why have I suggested Callisto? Easy: the only Galilean moon of Jupiter which is long-term habitable and relatively unaffected by the Jovian Van Allen Belt radiation. It has reasonable gravity and a trace atmosphere. It's also at the limits for a manned mission, if nuclear thermal rockets are used (Nerva engine). Another possible lander/rover destination might be Ceres?
What I'm looking for is maximum scientific return for the money spent.
It simply makes more sense to "expend' the SLS and simply discontinue the further production. Get whatever we can from the existing hardware, but don't throw any additional money at it.
SpaceNut-
These "one-off" designs keep more engineers and scientists employed...and keep NASA in business.
Well, with an already built SLS rocket waiting for a payload (or 2), the price would seem to me somewhat already amortized by the billions already spent on the development of this monster rocket? So--how much $$$ would 2 surveyor type vehicles cost us...we the taxpayers? Building a Mars type rover for Callisto should not be an issue, but only the power source is in question. It would need a mini nuclear reactor in order to have rover power as well as ample power for signal transmission. The Europa mission would require a lot more thought, which at NASA is expensive.
I've commented elsewhere about the SLS and that it's a rocket without a mission. Howzabout destination Jupiter? The SLS could readily fly 2 probes to the Jovian moon system. NASA has already pontificated about a possible probe to Europa, and my interest is in the outermost of the Galilean moons, Callisto. What I'm proposing is that one of the otherwise worthless and hyper-expensive SLS rockets do a piggyback payload and send 2 lander/explorer probes at once; the stages could separate after passing the asteroid belt, and become independently targeted after any midcourse corrections are made. The extreme Van Allen-type radiation on Europa would probably doom any lander to an extremely short mission lifetime, but the Robert Zubrin idea of a thermally heated penetrator could be utilized and signal transmission to an orbiter might just work there? Callisto, on the other hand, is out of the Jovian Van Allen Belt and has been suggested as another possible site for a human outpost. How about a lander to do some regolith sampling and atmospheric studies. The radiation exposure is also important to measure.
Although I'm strongly a "let's go to Mars first" man, getting our money's worth from the SLS system would bring some return on the taxpayer's investment in NASA.
As an addendum to my previous post:
A timeline for Mars Exploration and Development:
2018-SpaceX landing demonstration using aero-braking and retro-propulsive landing. Possibly carrying the Sabatier reactor and Oxygen generators.
2020-SpaceX landing of a larger payload; vehicle should/could carry a supply of food and a 100Kw Nuclear reactor.
2022-SpaceX landing of second Nuclear reactor and possibly a small rover suitable for manned use; more pre-positioned foodstuffs.
2024-SpaceX landing of the BFR (another appellation for the ITV, MCT, etc...whatever name they're using this week!); LOTS of food, construction supplies for erection of a Habitat; POSSIBLY a human crew. Given the delays in the Falcon Heavy program, highly unlikely by 2024.
2026-More likely to accomplish the goals stated for 2024.
2028-Most probable first manned mission.
As this is strictly one man's best guess, along with much hand waving, feel free to hit me with all the slings and arrows of outraged fortune!
I've mentioned on another thread the necessity for a full Nuclear power plant in at least the 100 Kw range of output; that happens to coincide with Dr. Zubrin's Mars Direct planning. Actually, the concept of having 2 of them is even better; these could be flown there well in advance of the first human mission, along with the robotic Sabatier reactor system. I'm in agreement with a minimalist approach, but having a bit more backup equipment and food/water available is the better option. One Nuke plant for propellant and LOX production, in addition to another one for the Habitation and as a charging station for a battery operated short distance rover. My idea for the rover is a roof and sidewalls covered in solar panels. Elon could actually get the ball rolling with his Red Dragon flights beginning next year; load the vehicle with food and other necessary survival supplies in addition to the experiments. This could preposition maybe 1500 pounds of food as an emergency backup food supply for the first missions. Granted, this isn't nearly enough to sustain an isolated crew of 7 explorers for the 550 days between Hohmann Transfer windows. How much food is required? My calculation is based on the following: each crew person requires 2% of their body weight per day of highly caloric food in order to do outside and exploration work involving physical labor. I have chosen a 7 man crew based on realistic manpower and mutual psychological support. I've allowed a 200 pound per person weight, although this is probably erring on the high side of requirements. An FAA standard "passenger" is 170 pounds, so smaller individuals DO need apply!
So... here's the math for food stockpile needed for said crew: (200 pounds per person)x(7 persons)x(550 days)x(0.02) = 15,400 pounds of prepositioned food. Granted, some food will be brought along with the Mars crew, but based on my calculations, not enough to last the entire duration of the mission between Hohmann windows. So...how do we cope with these requirements? Smaller crew members stands out immediately; reduction in the size of the initial crew comes in second. We cannot reduce the calories needed without severe mission success and health complications. Why have I chosen the number of crew members that I have? It's based on a military principle of "triads," groups of 3 sent to perform ANY task. A triad can almost always effect a self rescue. One tem member injured? Then there are 2 team members available to move the injured to a safe haven (a rover). With just a single small rover, one triad at a time will be outside the Habitat doing research. The second triad will be doing a combination of (1) resting, (2) housekeeping, (3) sample and data analysis, (4) further mission planning. I have included a 7th person as a Mission Commander, and as a completely qualified backup to any other mission member. Like it or not, as a former military Squad Leader, there has to be someone "in charge of things," or chaos can result. These first missions will have, out of necessity, somewhat a military organizational flavor.
As an alternative mission model, we could do either a 4 or 5 crewmember mission, but the odd number is best at breaking any impasse w/r to mission critical decision making.
Food requirement for a 5 crewmember mission, all of smaller stature/weight at 170 pounds; calculation: (170 pounds per crewmember)x( 5 crew members)x(550 days)x(0.02) = 9,350 pounds. And no...I haven't even begun to calculate the water required. A major water reclamation system is essential, one similar to that on the ISS. That could also be flown ahead and in place in a prepositioned Habitat module.
Those of us here at the Mars Society website have a far better appreciation of just how much is involved with a human mission, much less a colonization effort. This is where NASA should be involved, not building a next to useless SLS system.
I envision something a bit less optimistic and certainly less grandiose than those of Elon Musk for our first efforts, but a permanent presence on the Red Planet is in my goal. These first missions to land pioneering equipment should be the goals for 2018, 2020, and 2022. I'd LOVE to see a manned mission by 2024, but realistically not until 2026 or 2028. Not unless some serious cash is thrown at the problem!
GW-
Check my post # 28 for the nomenclature for the SLS. For the amount of money thrown at the SLS, NASA could have paid SpaceX to do a Apollo 8 Redux AND an Apollo 11 Redux. I for one, have little interest in repeating the Moon, a far scientifically less interesting place than Mars.
NASA really needs to begin designing missions, and then put out requests for bids; they really need to get out of the Deep Space hardware business. Build into these requests a hard time line for completion, too.
There really isn't much need for the inert sweeper gasses for an engine on mars, since the external pressure is only ~ 0.01 ATM. The burned gasses would exhaust themselves readily. It would take a bit of research, but an engine running on O2 and CH4 should be easily designed. The metals incorporated would probably need to be something similar to Inconel for maximum heat and oxidation resistance.
Actually, the buffer gas could be wasteful utilization of the CH4, although this may foul spark plugs. CO2 has a negative effect on combustion processes.
My suggestion, re: power source for the rover did not depend on gaseous oxygen, but a tank of LOX. An engine powered by the tanks of LOX and LCH4 could go a long way. Those fuels are already postulated for production to facilitate the Earth Return.
President Trump seems to have Lockheed-Martin reeling in retreat from the $379 Million per copy price on the F-35, and a new negotiated price more like $600 Million less on an order for 90 aircraft. He needs to get involved in the SLS program before it destroys NASA politically.
Robert-
I agree completely, but we cannot ever figure out the politicians and what they'll do with the SLS.
SpaceNut-
If ULA could add a landing system, it would become a lot more reasonable for ongoing development of the SLS. The legs aren't the only mod needed, however; reentry steering fins, along with a thruster system are also necessary.
Once again, the word "Boondoggle" leaps to mind. We are building--at taxpayer expense--a giant rocket without a defined mission. These vehicles are not a "one size fits all" item, and what's happened here is it fits none of the missions of manned spacefaring requirements.
This is a direct consequence of the Obama WH cancelling the Bush WH Constellation, and a reluctant Congress with constituents screaming about the jobs and revenue "lost," insisting on keeping something for the money wasted.
So...for $400 Million we get approximately 15% more performance than a Falcon Heavy for 4X the price? Not to mention all the re-engineering required to make it recoverable?
GW--
I like the idea of getting something a lot more valuable than another chunk of space debris. I would not hesitate to state the new administration should examine your proposal. On the other hand, why not just make the SLS a launch vehicle for the proposed Mars version of the ISS? A SMALL version, however. Didn't either Boeing or Lockheed-Martin suggest something like this? It would not take until 2028 if they used this existing hardware. I believe (and strongly hope!) that the Asteroid Redirect/Retrieval will die from disinterest. The future of manned space exploration is shifting from the "usual players" to SpaceX. Once Falcon Heavy begins flying, we can all rejoice.
This discussion has pretty well dealt with the "hows," but in general failed to justify the mission on the basis of science. I just cannot somehow get my head to justify the huge expense of the SLS as a "throwaway."
Terraformer-
Even after consideration of the 36 ton to orbit based on complete recovery of the booster stages of the Falcon heavy, rather than the 53 tons to LEO as a throwaway, this is pretty good bang for the buck. That calculates to $2.72 million per ton. After we adjust for first stage recovery by deducting $16M/ stage recovered from the cost by making a second launch cost $50M, that subsequently reduces the price per ton delivered to LEO all the way down to $1.39 M. A second re-use of the boosters should reduce the cost per launch even further, and as GW has calculated, around $1 M per ton. Or less, if we give a basic cost to range management, refurbishment of stages between flights, and roughly $200,000 for RP-1 and LOX per stage per flight (Musk's figures). Maybe we use a figure of (just a WAG!) of $20 M per launch with all ancillary costs included for a completely amortized set of stages, brings us down to a figure of ~ $500,000 per ton to LEO. There's simply NO WAY that ULA can compete with the SLS. This is bringing down the cost of...gasp!...Orbital Tourism!
NASA cannot seem to get their heads wrapped around the idea they're no longer the only game in town. Do they really want to compete with Elon Musk, or work in concert with SpaceX? Utilize NASA assets to construct a Martian GPS system for the planet, bring a nuclear reactor, transport a drilling rig for water; these are all "things to do." Mars has no magnetic field, hence compasses are ineffective for surface navigation; GPS solves the problem of surface navigation. A reactor supplies ample power for a ISPM, as well as power for heating and lighting for the first small outpost.
I believe the cost per ton to LEO will ultimately go far below the cost calculated by GW Johnson, based on the ability to recover at least the 2 strap-on Falcon 9 booster stages with a high degree of probability, and also the central core, probably on the drone ship.. Elon Musk has stated on one of the webcasts that they cost SpaceX about $16 Million each, so 3 x $16 Million saved from the initial throwaway price of $98 Million a launch is essentially halved, if we don't calculate the refurbishment and profits. A second recycle of a stage becomes even more friendly w/r cost to LEO. There's simply NO WAY the SLS system can compete. ULA better make their money now, because their rice bowl is vanishing...
Compare what the CEO of Lockheed-Martin has agreed to do w/r the F 35 Multirole fighter.
Near as I can figure--the SLS is simply a reiteration of the defunct Ares V heavy lift version in the Constellation Project. I have no idea how much $$$ has been spent on this white elephant. A not-heavy-enough Heavy lifter. It's powerful, but not enough to do anything other than a possible Apollo Redux. Using it for some deep space, outer solar system probes would make more sense than the asteroid redirect. Very expensive science, though. Maybe NASA could undertake a Mars landing with a Kilowatt range nuclear reactor in support of a SpaceX mission? That way it would be a one-way trip, and the $$$ would then vanish forever?
I would rather see some of NASAs resources utilized towards a major probe to the moons of Jupiter than the stupid asteroid redirect mission. Europa and the other outer moons are scientifically interesting, as Callisto offers a potential base possibility away from the radiation hazards of the Jupiter van Allen belts. A lander on Europa would offer a much higher scientific payback than some of the other NASA projects.