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Most of your points are fair. A couple counter points: President George H. W. Bush announced his plan for long-term funding for NASA in June 1989, on the 20th anniversary of the Apollo 11 Moon landing. NASA spent 90 days writing a report to detail how to accomplish his plan. The 90-Day Report was intended to be spread across at least 2 decades, but instead of giving cost estimates per year, it gave one big price for the whole plan. When Congress saw the $450 billion price tag, they choked! In 1989 dollars. But again, it was never going to be paid all at once, it would have been spread over decades. After Congress rejected it, Martin-Marietta assigned their engineers to come up with a plan that was more practical, something Congress would accept. They split into 3 teams, one was Dr Robert Zubrin and David Baker. The teams helped each other; doesn't always work that way, but in this case it did. Mars Direct is what they came up with. My point is the worked on it the last quarter of 1989 and the first half of 1990, presenting to NASA in June of 1990. They had 8 months to develop the plan, not 2 years. There was work off-and-on to design a heavy-lift launch vehicle using Space Shuttle parts since the late 1970s: Shuttle C. Work on what became Ares started in 1988. But everything else in Mars Direct was just 8 months.
There have been some updates to Mars Direct. When work on the SP-100 reactor was completed in 1992, they had to update mass estimates for that with actual real mass of built hardware. And the original habitat was only 1 deck, the upper deck. One issue raised very quickly after the presentation to NASA was landing rockets would kick up rocks, so simply strapping the rover to the underside of the hab was not a good idea. The rover could get damaged. So the lower deck was added to protect propellant tanks, and a storage compartment for the rover to protect it during landing. Once they had a lower deck, they moved the airlock there. So a staircase to the airlock door instead of the original tall ladder. ISS didn't become operational until July 2000, and US life support didn't operate until some time later (2007?). Experience showed life support requires maintenance, so the original Mars Direct hab with life support in a sealed compartment beneath the floor of the one deck was not practical. The lower deck could house life support where astronauts could access equipment.
Materials: Apollo CM
Pressure hull: "aluminum honeycomb between aluminum alloy sheets"
Outer shell: "stainless steel honeycomb between stainless steel sheets"
Mars Direct hab was supposed to be made of "weldalite", which is aluminum-lithium alloy. It's lighter than the aluminum alloy used for the Apollo CM pressure hull. I didn't read anything about an outer covering, but I always assumed it would use the same thermal blankets as those used for modules on ISS. For ISS, they provide both micrometeoroid protection, and thermal protection. Their outer layer is Orthofabric, with multi-layer insulation inside the "quilt". Upgrading the TPS for backshell protection during Mars atmospheric entry... yea, no duh.
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RobertDyck,
Dr Zubrin and The Mars Society have had decades to refine their concept of operations, subsequent to delivering their report to NASA, into something approaching an engineering solution using hardware NASA actually has on-hand. Dr Zubrin is an aerospace engineer and this is his pet project. Why is he still making the exact same sales pitch using concepts and hardware that are over 35 years old?
Take a look at the strength knock-down factors once you start welding 2195:
The Evolution of Constellium Al-Li Alloys for Space Launch and Crew Module Applications
NASA began exploring automated fiber tape laying machines and out-of-autoclave cured composite cryotanks to cut down on the incredible cost associated with machining and welding 2195. The switch back to 2219 for the SLS propellant tanks was for that reason. Try to imagine how expensive 2195 fabrication must be that using composites and automated fiber tape laying machines was 25-30% cheaper. Part of the cost could be explained by the fact that fabricating the composite tank takes about a week and 1 to 2 people are present babysitting the machine. Boeing, ULA, and others have an entire team of machinists and welders to fabricate Aluminum pressure vessels, and it takes them several months.
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A lot of the ideas of Mars Direct are far in advance of any other mission plan. And after he pitched it to NASA in June 1990, one of the NASA centers was strongly in support. With NASA on-side, there was a real possibility it would happen. So he didn't want to fundamentally change it. However, he did pitch "Star Boat" a couple years ago. A completely redone mission plan.
Elon Musk has the idea of sending a lot of cargo with one-way Starships. Then send a 100 crew mission as the first ever human mission to Mars. And the only way to get back is in-situ propellant production. Enough propellant for Starship. Can we agree that Elon's plan is not optimal? The first mission should be much smaller, with no dependence on in-situ resources other than atmosphere?
The NASA team who developed DRM made a number of changes that are just frustrating. The old engineers who worked on Apollo like the idea of a 4-person crew. After all, the idea of 4-crew came from NASA's mission plan of 1965, so it's their idea. And they got that number from the fact they could squeeze 4 crew into Apollo if all food and extra lithium hydroxide canisters were removed. The frustration was younger engineers from the Shuttle era wanted 6 or 7 crew, because Shuttle carried 7 crew. That's where the crew numbers came from, not anything practical. Increasing a Mars mission from 4 to 6 crew significantly increases total launch mass.
They also wanted to abandon ISPP, bring return propellant from Earth. That dramatically increases launch mass. And now you are arguing whether ISPP even reduces launch mass. If you want to continue to argue that point, please read the book "The Case for Mars". Every member of the Mars Society should already be familiar with it.
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RobertDyck,
I get why change is hard, but after as much time as has already passed us by, I think it's time to update plans to sync-up with actual hardware. A lot of tech development has taken place since 1989. The Falcon Heavy / Dragon update was interesting and has some potential, but right at the edge of technological feasibility. The mass margins are a bit too tight.
If SpaceX can successfully land robotic cargo-bearing Starships on Mars, then we're much further along than we've ever been in the past, even when the Saturn V and NERVA were on-offer. Is the SpaceX plan any better than Mars Direct? Perhaps it is to Elon Musk, but not to my way of thinking. Any vehicle sent to the surface of Mars, beyond a small reusable MAV to return people to LMO, needs to stay there. The energy cost of returning it to Earth is far too high.
If Starship ever straightens up and flies right, then we can do 8-person crews fairly easily. I wouldn't fret too much over the launch mass if we can send 200t to LEO with full reusability. If NASA will only pay for 10 launches per mission, then each mission has 2,000t of mass to work with. We can do a pair of 20t 4-seat MAVs, a pair of 50t surface rovers for real surface exploration, and a 100t ITV.
Using a combination of minimalist MAVs, chemical, and electric propulsion, we're not straining our propulsion capabilities at all. ISPP is a worthwhile program objective, but pursuing it should be a second priority to the primary objective of surface exploration. We can't do that if all the money, intellectual effort, and irreplaceable time is spent pursuing these side quests. We already have storable chemical propellants and suitable engines that only need to be integrated into a minimalist ascent vehicle.
If we're only interested in getting the job done, then we're going to use the simplest and most highly developed means of accomplishing major mission tasks, such as return to orbit, and forego better options, such as ISRU / ISPP, as program features that are worked into the exploration campaign as the technology matures to the point that it can be incorporated into future missions. That's how the ISS technologies were developed. We should go to Mars first using the propulsion hardware we already have and enhance our capabilities with ISRU / ISPP over time.
The first lunar missions did not have a rover because the tech wasn't ready. If we had to wait additional years because we mandated lunar rovers for each mission, then President Kennedy's timeline for lunar exploration would not have been possible.
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I have proposed updates many times. Getting people to listen to me is also frustrating. My first presentation at the Mars Society convention in 2002 was met with hostile opposition by Mars Society members. How dare I propose even a slight change to Mars Direct? I had proposed not dropping the Earth return capsule on Mars surface, just to lift it off again. And a larger ITV left with the capsule in Mars orbit. A light expendable MAV. Back then Shuttle was still flying, and X-38 was under development as a crew return vehicle. So I proposed the Mars capsule not be used to return crew if they didn't have to, instead dock the ITV with ISS upon return from Mars. Mars crew could return on Shuttle. A fully reusable ITV and the Mars capsule also kept as an emergency escape pod which is not replaced if not used.
Notice my architecture uses an expended MAV. The MAV is the TMI stage.
ISPP is critical to keep launch mass down. Abandoning something so basic results in program cancellation. We've seen this many times with robotic sample return. Someone would notice that a Mars sample return mission could be done within the budget of a standard NASA Mars mission. People get excited, the program gets funded, progress is made. Then some scientist demands that he doesn't want any new technology on "his" mission. Any new tech. At all. ISPP get cancelled. That dramatically increases launch mass, which dramatically increases program cost. Cost is now 10 times what NASA (and politicians) are willing to pay for a Mars mission. The entire program gets cancelled. This cycle has repeated several times.
With human Mars missions, the price estimate was $20 billion for research and development plus $2 billion per mission for Mars Direct in 1989 dollars. But that was before Shuttle was cancelled. Ares was supposed to be manufactured with the same tooling as the ET, and use the same main engines as the Shuttle orbiter. So no development cost. After Shuttle was cancelled, tooling for ET was scrapped, so they needed new tooling for SLS. And for some frustrating reason, even through SLS engines were taken off Shuttle orbiters, Boeing managers demanded cost for engines must be charged as much as a new engine. But even before SLS, NASA designed DRM. It increased crew from 4 to 6, and return propellant returned from Earth. The price estimate for Mars Direct was from Zubrin, it was from NASA's budget office. But DRM would cost $55 billion, which doubles the cost and that's before any hardware was built. Congress was afraid NASA would demand the entire $450 billion from the 90-Day Report plus inflation since 1989. Ironic thing is the 90-Day Report included a space station in Earth orbit (ISS), a launch vehicle as powerful as Saturn V (SLS), a capsule to return to the Moon (Orion), a human Moon mission. NASA is doing the 90-Day Report anyway.
We need to control cost. Using the same damn excuses that got programs cancelled will only result in getting your program cancelled.
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RobertDyck,
We need to control cost. Using the same damn excuses that got programs cancelled will only result in getting your program cancelled.
We're already doing that to a far greater degree than ever before.
Back when we were paying $54,500/kg, launch costs were a major factor in any space program's success or failure. Starship's launch cost is projected to be $10/kg. Let's say they're off-the-mark on launch costs by a factor of 10. For every 1kg we could launch at Space Shuttle prices, we can launch 545kg at Starship prices. A 2,000,000kg mission package, at $100/kg, is only $200M. Spread over two years, NASA's total investment per year is equivalent to a single Falcon Heavy Launch. If NASA won't commit to that level of investment in launch services for exploration, then our manned space exploration program is a farce that we should dismantle so that something functional can take its place.
If Starship truly can lower launch costs to $10/kg, then I don't know why we're arguing over $20M per Mars mission. There are at least 2 million Americans would donate $10 in gas money to NASA if it meant we could sit down at dinner to watch a televised Mars landing with a crew of astronauts. The entire world was glued to their TV sets when we did the lunar landings. That event was so fundamentally different from anything else in the human experience that they could not look away.
As I said before, and will continue to repeat, ISRU / ISPP will not make or break a Mars exploration mission. In any case, it's not ready to implement because no serious money or effort has been devoted to using it. ISRU / ISPP has become a toll booth, sort of like the Lunar Gateway.
We have life support, as well as air and water recycling equipment, that's good enough to do the mission.
We have storable chemical propellants and electric propulsion for return to Earth, good enough to do the mission.
We have heavy lift launch vehicles, such as Falcon Heavy, that are powerful enough to do the mission.
We have capsules and habitat modules that are large but light enough to do the mission.
Let's argue over what we could have done better or differently... After we do the mission.
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Robert Zubrin got it down to 2 launches of a Saturn V class launch vehicle. I had broken mine up to use Russian Energia, but that was when Boris Yeltsin was president and shortly after. Before Putin started his military campaign to put the Soviet Union back together. I wasn't the first to propose Energia; Robert Zubrin included it in his 1997 edition of his book. Currently my plan requires 3 Starships and one Falcon 9. Considering they're reusable, I think it's justified. But doing stupid things will get the mission cancelled.
Elon's idea of sending supplies then send 100 settlers for the first ever human mission is even more stupid. Start small, prove technologies and techniques, prove in-situ resources, and grow. I argue the 100 crew mission should not happen until after a small permanent base is already built.
Yes, we can use Starship as a launch vehicle. Commercial investment will not be interested until after going to Mars is proven. If Elon uses resources of SpaceX for the above plan, and something goes wrong killing people, then commercial investment and government will stay away for at least half a century. And something will go wrong on the first mission. The key is to ensure people don't die, there are successes, and lessons can be learned.
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I posted here on NewMars about St John's Newfoundland. Fishermen started fishing there in the late summer of 1496, built the first permanent house in the summer of 1497 for a caretaker to overwinter. The city of St John's celebrated their 500th anniversary in 1997, because they count their founding as that first house. This is long before Jametown, long before Roanoak, long before many failed government colonies. The reason so many government colonies failed is they depended on food sent from Europe. If a settlement on Mars is dependent on food sent from Earth, it will also fail. Expect politics to result in delays of shipment of supplies by months or years. It happened in the 1500s & 1600s, will happen again. Period. No question. The reason St John's succeeded while other the others failed is they were food independent from day one. They were also energy independent; although back then ships were powered by sail, so wind. Drying racks to dry fish fillets used air and sunlight. Drying racks were made from wood harvested from trees locally. Initially they lived on the ship, with tents setup during summer, return to England when weather got bad. But eventually they built log cabins, made from logs harvested from local trees, and heated with a fireplace that burned wood, also from local trees. As the town matured, someone brought tools for a blacksmith shop. The blacksmith couldn't make fine steel required for firearms, or fine steel required for saw blades, but he could make nails, hammers, tongs and pokers fireplaces, simple tools. He could repair tools, etc.
The lesson for Mars is the first mission should be a science mission, not one-way. Bring food for the science mission, but bring an inflatable greenhouse to start developing and testing technology to grow food. The very same year the first permanent settlement or permanent base is built on Mars, food production must be established. The first permanent base must be able to produce sufficient food to keep everyone alive should supplies from Earth be delayed by two conjunction cycles. Not just one, but two. One conjunction is every 26 months, so 2 means 52 months. I didn't say weeks, I said months. That's 4 years and 4 months. Do I have to add a couple months to that? So food and energy independence from day one.
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Food independence would require much like the above example a setup mission that makes a working greenhouse so that the followup crew has less required food stocks to continue building towards a mars settlement.
Success of first crew means preloading landing site so as to get more work done.
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