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You keep repeating the same error. Yes, I agree that defence (Canadian spelling) contractors want big spending. Yes, we need to keep cost down. Congress said "No!" to the 90-Day Report because it cost too much. The problem is you keep assuming that splitting a single, shared spacecraft into multiple single-person landers would actually reduce mass. I've explained why it won't.
Let me put it another way. Physics is real life. This isn't some Hollywood movie or TV show. The TV show "Stargate SG-1" showed aliens with technology that looked like ancient Egypt. It's based on the initial premise of the show. A couple episodes showed an escape pod that looked like an Egyptian sarcophagus. Some episodes showed a horizontal sarcophagus as some sort of medical device, other episodes showed a vertical sarcophagus in a Tel'Tak ship as an escape pod. Well, in real life a sarcophagus is a coffin. Just a box to hold a dead body. It isn't an escape pod. In real life an escape pod cannot be a form-fitting coffin-shape. In real life an entry vehicle must deal with high speed atmospheric entry.
Studies by NASA in the 1950s showed a blunt body works much better than a sharp, streamlined vehicle. A blunt body means a round heat shield, and an aeroshell behind it. Wind tunnel studies showed air flow behind the heat shield in a specific pattern. The reason a Mercury spacecraft has the shape it does, is that fits within the wake behind the heat shield. A cone of specific size, with specific angle to the side walls. At a specific distance behind the heat shield, the wake stops collapsing inward, forming a fairly straight cylinder of turbulent air. The nose bit of Mercury, fits within that. Mercury used that to store its parachute, flotation bags, and life raft. And above that was the antenna fairing. But you don't need to use that space. A spacecraft that docks to something, such as ISS, would have a rounded-off, domed top with a docking hatch rather than that nose piece.
Rob,
Get the whole MOOSE concept out of your head. NASA isn't doing space jumping stunts on Earth or Mars or anywhere else there is a potential alternative EDL method.
The only way you need a capsule the size of Mercury is if you insist on laying the astronaut flat on his back. The human doesn't have to be oriented that way in the capsule for a Mars landing because we're not executing a Mercury style landing on Mars.
Imagine for a second that we're using an inflatable heat shield, which is what I proposed, and that the capsule's seating arrangement is such that the astronaut is sitting in a fabric seat in a more vertical orientation, relative to the nose of the capsule, instead of laying on his or her back. If the capsule was designed with that seating arrangement, then it doesn't have to be as wide as mercury.
I never proposed using a Mercury capsule with a conventional heat shield because neither the capsule geometry nor its seating orientation are required for a Mars landing. As far as your physics lesson is concerned, in real life the IRVE payload container had a vertical orientation. In real life, an inflatable heat shield can be deployed from the base of the service module and would permit a much smaller diameter capsule and therefore lighter capsule. Most of the capsule's mass, even after expenditure of propellant, is in the base.
GW,
Nobody here wants to get anyone killed. Some other ugly little facts have to be faced, though. There isn't a good solution for every potential problem. In the same way that missing the runway normally results in death and destruction here on Earth, such is the case on Mars. You land where you're supposed to or your odds of survival are slim to none. We've launched over 100 Space Shuttle missions and never lost a single orbiter to pilot error. You get one and only one chance to get it right, which is why older men and women with thousands of hours of flight time in multiple airframes are the only ones permitted to fly it. To channel Chris Costa a little, if you're a professional pilot then you practice landing until you can't get it wrong.
Minimum mass missions don't necessarily make the missions more dangerous to the crew if you're intelligent about what you send to Mars. Even something as simple as the pressure vessel for landing clearly illustrates the problem with all the solutions I've seen from NASA. Nearly every concept attempts to use some novel technology or combination of novel technologies that demonstrate how clever their engineers are as opposed to designing something simple that works or adapting existing technologies for their purposes. Obviously it makes the problem more interesting, but is the goal behind the development work to make the solution intriguing to the engineers and scientists or to use simple and workable solutions that function in the real world where cost and complexity are real problems?
In simplest form, a lander (for humans) is a maneuverable pressure vessel with a thermal protection system. There's no requirement for landing everyone in the same capsule. That's just defense contractors who want big spending programs to collect as much money as possible from the tax payers. I don't care about the spending programs if there's unlimited funding available and we don't care how long the solution takes to develop and test. In the real world, there's no such thing as unlimited funding, so let's pretend for a moment that we have work within the constraints of a rather small budget for the undertaking that NASA says it wants to attempt.
We can make the human EDL solution for Mars as heavy and complicated as is pleasing to us, no doubt producing a whole range of other problems that require solutions of their own, or we can accept that smaller and simpler can and will function just as well as heavier and more complicated in actual operations.
But the habitat that can move is to heavy for current EDL systems to handle.....
In terms of the added mass if it means survival and death I would take it to and give up something else that is coming down with the crew member that can have a bit of mass trimmed from it.
I already proposed a minimum mass and development effort EDL solution to get humans to the surface of Mars in another thread. Nobody liked the solution, but the alternative is a multi-billion dollar project that will take NASA a decade or longer to develop and test. The funding saved would support development of HIAD and ADEPT along with habitat modules.
The habitat module, mobile or static, will be heavy. Use of the new EDL technologies JPL is developing is a requirement.
I think an electrically powered M113A4 (MTVL) with band tracks (presuming the tracks were made from a compound with a very low glass transition temperature) would be suitable for Mars exploration with modifications. The roof would have a giant solar panel on it. Top speed should be governed to about 30 kph. The vehicle would weigh about 20t fully loaded. Unlike the MTVL, the batteries would be on the floor and only electric motors would be utilized for propulsion. The walls and roof of the main compartment would contain a HDPE water bladder. There would be no hatches above the driver's compartment and the compartment would be heavily shielded. The M113's ramp would be replaced with an airlock or suitport. Each MTVL habitat would carry a crew of two.
I do not want to get this topic any further off as we have the past topic to dicuss this in with a greater level of reasonable detail.
I will post one one of them...
I think small powered vehicles are a total waste of mass, time, and effort. The habitat module should be mobile and come to you after you land.
The Montanara Volta weighs just 9 kg and uses an electric motor to assist the rider.
https://www.electricbike.com/lightest-bike/
In contrast, some of the lightest gas powered bikes weigh more than 59 kg.
Is the gas powered bike worth the extra 50 kg? It's certainly much faster than the pedal powered bike, until it runs out of fuel. Should astronauts travel around on Mars at 30+ km/h wearing thin pressure suits? Probably not smart.
For comparison purposes, a high performance electric bike like the BRD RedShift weighs 114 kg.
If you can't go to the habitat module on Mars by foot or pedaling, then perhaps the habitat should be mobile and come to you.
That said packaging in some sort of low tech transporting a suited crewmember would be a must unless we can garantee landing within 500m from the rest of the crews supplies and habitat as the limiting factor is the suits capability to support life.
I posted a thought about making a vehicle engine run by fuel injection of hydrogel fuels into a ICE engine, what do you think reply in the other topic please.
My take on small powered vehicles like dirt bikes or rovers is that while they could prove quite useful for contingency purposes, they add lots of mass. Sending the first astronaut down in a micro capsule to retrieve the mobile habitat gives the rest of the astronauts a much better chance at being rescued should one or some of the capsules miss the intended target. If you're the first one on Mars, you're taking a calculated risk. Everything could work perfectly, or your friends may bury you there. In short, I favor a phased landing approach that doesn't run the risk of killing the entire crew in one go.
Perhaps it'd be better to simply send two extra oxygen bottles and a small pedal powered bike with the astronauts rather than a chemically powered vehicle. Everyone here seems to have the same complexity cravings that NASA has. Keep it small and simple.
Rob,
I expect that we can land within 50 km of a landing beacon and closer than 10 km in all probability, a figure that's generally accepted by JPL as what we're currently capable of. If we can't land within 10km of a target, then we probably shouldn't send humans to Mars. Curiosity landed 2.4 km from its intended target and Opportunity landed 2.32 km from its intended target. That's pretty good, but still not good enough. I have no idea how close Pathfinder landed to its intended target. Our accuracy target is 1 km or less, with .5 km being the goal. That's JPL's idea of a precision landing.
With surface radio beacons and perhaps a GPS constellation (something Mr. Musk wanted, if that ever proves feasible), I think we can lick the landing precision problem. We also need a high precision surface map, like that provided by MGS, for terrain avoidance. I'm aware of what MGS and MRO provided, but I want confirmation using a second source or multiple sources. If we have a GPS constellation at Mars, laser altimeters on those satellites should also continually map the surface. It's simpler and easier to use high precision maps and have systems that indicate precisely where you are, relative to a point on the surface or other satellites, rather than trying to incorporate a reliable terrain avoidance radar system into the landing avionics. Terrain avoidance radar would not be doable for a micro capsule with the mass constraints I have set for it, but it would be doable for a larger multi-person lander like Red Dragon.
I do not wish to abandon the use of multi-person landers stocked with supplies and perhaps a rover as the preferred method for landing humans on Mars.
Maybe a better potential solution to the landing precision issue is to litter general landing areas with supplies so that even if you're 50 to 100 klicks off target you still have air, water, and fuel (if we land dirt bikes or rovers). Each supply cache would have a beacon, as would the habitat modules and rovers. If you can't land within 100 km of the habitat, Mother Nature permanently revokes your pilot's license. As previously stated, some things you just have to do correctly.
Dry mass of Dragon is what you listed. With full propellant tanks, it's 8.0 metric tonnes. Compare that to Orion: 28.0t with full propellant tanks, fairing around the service module, and Launch Abort System.
The capsules I proposed won't weigh more than 1t. In your opinion, would 4t for backup capsules of extremely simple design be worth their weight on a mission? Dragon Rider is nowhere near completion of development for a Mars landing, so would it be fair to say that we're going to spend quite a bit of money irrespective of whether or not we design a one person capsule from scratch or develop Dragon Rider to the point where it can reliably land on Mars?
In the discussion thread Light weight nuclear reactor, updating Mars Direct, I described using Dragon as the ERV capsule. Orion is way too heavy. So we're actually in agreement. The only difference is your solution to Orion is to design something new from scratch. My solution is Dragon.
As previously noted, Dragon Rider would require at least one unmanned test on Mars. How many one person capsules can we reasonably afford to test on Mars in comparison to four or six person capsules?
Grammar? None of us are English majors. I'm just not sure I understand what you wrote.
Poor sentence structure.
Multiple backups are generally good. But you have to look at how your backup will work. How would a single person capsule be used? Abort to the surface would leave an astronaut thousand of km away; possibly the other side of Mars. No habitat, no ascent vehicle. How long can you live in a suit?
A single person capsule will be used the same way a multi-person capsule will be used. In either case, the capsule has to land with precision near the habitat module on Mars. We can afford more testing of single person capsules to ensure that the capsules land exactly where intended.
If you're nowhere near your habitat module and you don't have a fully fueled ascent vehicle, then you're dead. The number of corpses per capsule is irrelevant. I've already gone over that at some length. Some things you just have to accomplish, period, or you don't come home. Loading a multi-person capsule with weeks of supplies and a rover will only ensure that it becomes exactly what Orion is- too damn heavy to easily land or send to Mars in the first place.
We seem to have conceptual disagreement about what a lander is supposed to be. To my way of thinking, a lander is supposed to get you to the surface of Mars, not serve as a lifeboat or a habitat module or attempt to account for all possible contingency scenarios. If you want to come home, you properly test things ahead of time and train your astronauts appropriately. That's somewhat easier to do when the hardware is smaller and lighter.
In six years in the Navy, I never walked around any of the ships I served on with a life preserver unless I was on the flight deck and we were conducting flight ops. I learned how to swim in the ocean and how to jump off moving platforms long before I ever joined the Navy, something that's proven far more useful than running around with a life preserver on anytime I'm near the water. In rare instances a few people fell overboard or were blown overboard and far fewer still drowned. Many, many others, including myself, lived. The point is, everything in life is a risk and most actions to counter risk involve trades. Are the trade-offs for using heavy multi-person capsules that may take a decade or more to properly test worth the expense and opportunities lost?
Poor sentence structure. But we all agree Orion is a waste of money. It has only one purpose: an Apollo style mission to the Moon. Cancelling that would free funds for other things. However, we saw with Shuttle that cancelling a major project could result it getting nothing.
Now you're critiquing my grammar? Get real. Anyhow, let's revisit your last point about weight. You're pretty much proving my point about which concept would weigh less. We have Dragon and we will have Dragon Rider. Both of those capsules are far more reasonable in terms of weight than any Orion derivative ever will be. Dragon, a capsule without systems required for human use, weighs 4.2t. Dragon Rider won't be lighter.
And a single person capsule will never be used for Mars. Landing at some random location, thousands of km from base with no life support, results in the astronaut being just as dead. Any backup is required actually keep astronauts alive. The only conceivable use for a single person entry vehicle is from LEO. MOOSE was designed as a means to bail-out from orbit. It's a backup in case a spacecraft fails, such as heat shield tiles of Columbia. One reason mission control didn't order an astronaut to go outside and inspect before returning, was there was nothing they could do. Mission control commander hoped he could risk atmospheric entry, inspect the orbiter once on the ground. Video spotted something come off the orbiter during launch, and personnel found pieces of reinforced carbon-carbon on the ground. I could describe a rescue with a second Shuttle orbiter, but he chose not to. He gambled, but 7 astronauts on the orbiter are the ones who lost. If a Shuttle orbiter had a bail-out system, then perhaps they would take the care to actually look. Today Shuttle isn't operating, but we have astronauts on ISS. It would be a safety system. But again, that's the only purpose for a single person vehicle.
Why won't a single person capsule be used at Mars? Multiple backups are always nice to have, but if a pressure suit fails then the result is generally a dead astronaut. Should we require astronauts to use two suits, just to be sure we won't have a failure, or accept that space flight carries risks with it? What risks do single person capsules incur that multi-person capsules don't? You wanted to compare apples to apples, so let's do that. If a multi-person capsule that's carrying 30 days of supplies for four people lands significantly off-target, are the astronauts going to make it back to the habitat module? Probably not without a rover. I've already stated why we can't have a gold plated solution to every problem. Whether single or multi-person, the capsules are being used to accomplish the exact same thing.
Try finding ways to return astronauts to Earth alive, rather than elaborate ways to kill them.
That is precisely what I am doing, Rob. If you land off target on Mars, then unless you have a fully fueled ascent vehicle, you're probably going to die. The problem with the fully fueled ascent vehicle is mass. Even if EDL with any weight class vehicle was no problem whatsoever, launch costs still drive what we can and can't afford to launch.
Rob,
One last point. In the real world, any time you put all your eggs in one basket, you naturally become more protective of that basket. The same principle applies to NASA engineering. There's a reason multi-person vehicles have triple and even quadruple redundant systems and days or weeks of supplies. The engineers are concerned with killing everyone aboard because some stupid little part failed. Any multi-person lander is necessarily going to be built using different design criteria from a single person lander. It doesn't have to be that way, but it will be that way. You and I both know that.
kbd512 keeps claiming that single person entry vehicles will be light, while multi-person vehicles will be heavy. But let's not forget, the area of metal for the capsule hull. Let me use a cube to illustrate the point. A single cube 2m x 2m x 2m will have 6 sides, each 2m x 2m = 4m^2. With six sides that will be 6 x 4m^2 = 24m^2. If you divide that into 8 cubes, each 1m x 1m x 1m, then the outer faces will be exposed sides, but now you expose inner surfaces as well. The face of each cube is 1m x 1m = 1m^2, so each smaller cube has 6 x 1m^2 = 6m^2 surface area. But with 8 such cubes to enclose the same total volume, you now have 8 x 6m^2 = 48m^2. Again the reason you have twice the surface area to enclose the same volume, is the faces exposed by the cuts.
To enclose 4 astronauts you require a given volume for their bodies plus spacesuits. And a given mass for their bodies plus spacesuits. And a given mass of life support, either bottled oxygen plus lithium hydroxide, or if you use the Russian system a given mass of potassium superoxide. Enclosing that in a spacecraft hull requires a given surface area, which must be able to withstand the heat of atmospheric entry. Dividing that into 4 small capsules instead of a single large one, means more total surface area. That means more mass, so more heat shield and more parachute area to support that mass. A single vehicle can use a single guidance computer, single set of inertial sensors, and single radio, but with separate capsules each capsule needs its own.
Bottom line: separate capsules will always mass more than a single shared capsule.
How much more?
The mistake kbd512 keeps making is the assumption that the single capsule will have additional equipment, while single capsules will not. That is comparing apples to oranges. You can only compare apples to apples, which means a single capsule designed for atmospheric entry only, to separate capsules for the same purpose. When you do that, the single vehicle always has lower total mass.
Have you seen a multi-person capsule design that didn't include the kitchen sink in the design?
kbd512 keeps complaining about money wasted on something that will never be used. But his single capsules are just that, will never be used. I have tried to appease him by suggesting a minimum-mass/minimum cost emergency bail-out kit. That would be MOOSE. But he keeps obsessing about single atmospheric capsules.
Whereas a multi-person capsule that there isn't funding to develop will be used?
What you proposed was akin to a Redbull stunt. NASA is never going to permit astronauts to free fall to Mars encased in high temp styrofoam. I'm talking about a real capsule system, just not one laden with every conceivable survival aid.
Let me put it another way. For Mars, landing is not everything. You have to look at the whole system. How will you get astronauts off Mars, back into space? How will you get fuel to the Earth Return Vehicle? Will your ERV launch from Mars surface or Mars orbit? Either way, how do you fuel it? Are you arguing to bring fuel for return all the way from Earth? If so, how much additional fuel do you need to launch that fuel from Earth? So it's not just return propellant, it's also propellant needed to deliver that. When you add up everything, what is the total mass that has to be launched from the surface of Earth to get astronauts from Earth to Mars and back to Earth?
So, should we kill the entire crew in one go if some $2 part that costs $200 fails or perhaps just one crew member?
Presuming no F9H is reused, that's $700M in launch costs alone, which is still less than the price of a single SLS launch. The MTV hardware will run between $1B and $1.5B (note: this is not development costs, just what production of the hardware alone will likely cost).
Launch costs for a mission that includes a surface stay will be in the $1.5B range. A surface mission would involve the same assembly procedure for the MTV and eight mission precursor launches to push two habitat modules and consumables to the surface of Mars ahead of the MTV.
All assembly operations will take place at ISS. Since we insist on maintaining ISS, we should have the crew do something useful.
Re. launch vehicles, do bear in mind that even if you launch the ship as one piece (which is unlikely), you can still launch it dry and send the propellent up separately, and you can also launch it empty and outfit the habitat later. That means, even if you don't dock your fuel tanks and rocket module later (but why wouldn't you...) you still have over 50 tonnes to fit the empty habitat shell, fuel tanks, and rocket engines into. When you add in all the supplies, life support, furnishing etc, you could have something that's closer to 100 tonnes dry, using only F9H. If you *do* mount the engine stack on-orbit, and maybe another habitat module, then the entire ship can be much larger...
That's exactly what I was thinking. There's no requirement to have every component of a MTV in the precise configuration required to start a Mars mission as soon as you're in LEO. All of NASA's Mars missions require orbital assembly. This requires loading supplies in addition to docking some modules. What I've proposed, with respect to MTV assembly for an affordable Mars mission, has already been done numerous times to support ISS operations.
MTV assembly at ISS
F9H 1: primary module (docked to ISS until the propulsion module is mated to the MTV)
F9H 2: artificial gravity module and micro capsules (some assembly and docking to primary module required)
F9H 3: secondary module (docking to artificial gravity module required)
F9H 4: crew consumables (transfer to MTV required)
F9H 5: solar electric propulsion module (partially fueled, some assembly and docking to primary module required)
F9H 6: fuel for propulsion module (on-orbit transfer of propellant required)
ISS 1: ISS crew mates the MTV to the propulsion module for transfer to L1
MTV Orbital Transfer to L1
MTV 1: ISS crew initiates an automated transfer of the MTV to L1
MTV Exploration Crew Embark at L1
F9H 7: exploration crew use Dragon Rider to rendezvous with the MTV and then depart L1 for Mars; Dragon Rider returns to ISS for ISS crew return
In the same way that we orbited the moon before we landed on it, the first mission to Mars should be orbital only, no surface stay, so that's all that's required. That's affordable in the near term and therefore doable. To afford this, NASA has to end the Orion and SLS boondoggles first. There's a difference between toys and tools. Orion and SLS are toys. Interplanetary transfer vehicles, closed loop ECLSS, active radiation shielding, electric propulsion, and landers are tools.
I am also wondering how large we could make a module that sets on such a landing platform using the baseline of the Pheonix lander as we could send one down to the surface empty to serve as a building block for the habitat space. Then send down cargo containers to land nearby with tanks filled with water, a seperate lander for Oxygen or more water with the electrolysis system to make it as a stage for a future started sabitier reactor for life support.
I think JPL has the right approach for landing more massive cargo containers on Mars using HIAD / ADEPT, but if separating the cargo from the crew is a good idea for operations in LEO, then it's also a good idea for interplanetary missions. The crewed landers need to be so small and light that we can afford to test them many times and have astronauts land them on Earth from LEO.
I see this as a first toehold mission with a minimal crew going to mars using what we can do today as the building block for design of a mission.
That said a 2 person MTV/ERV is much smaller to launch as the large amount of water and consumables are by far less.
You're still talking about sending cargo with the crew. We need to divorce ourselves from that idea for exploration purposes. You either land precisely where you're supposed to and walk to your habitat module or you become a permanent resident. It's not as if thorough training and testing won't be conducted ahead of time. It's not economically feasible to have a solution for all possible contingency scenarios that far from Earth, so let's not waste time and money on it.
At this juncture, we still don't have deep space habitation module or propulsion module or closed loop life support, so multi-person landers are simply out of the running for economically feasible ways to get humans to the surface of Mars.
The problem with launch vehicle costs is not the only point to be made as the stuff we want to place into orbit when broken down into smaller piece cause the price of what we wanted in the first place to rise rapidly as we have to dock multiple sections together that are all different to make the complete item design. So there are trade offs for getting the launcher and the payload to match more closely to what we need.
SpaceNut,
That would be true if the orbital assembly operations were significantly more involved than docking a few modules, the cost differential between F9H and SLS was less significant, or there were significant issues with a module remaining in LEO for a few weeks, but none of that is applicable to the comparison between F9H and SLS. A launch vehicle that delivers less than 50% more payload for 10 times the cost of the competing, albeit less capable, launch vehicle is not a good trade in most cases.
If we're ever to have reusable transfer vehicles, then on-orbit assembly/dis-assembly/servicing is a requirement. Using launch vehicles of more modest lift capability is not detrimental to this goal and will force the engineers designing the transfer vehicles components to create plug-and-play solutions.
I would like to know everyones' thoughts on what funding priorities should be in a post-Orion, post-SLS world. I think it's pretty clear that there's not enough funding to use either of these two systems and that both are monumental wastes of the tax payers' money. Moreover, it is precisely because Congress is forcing NASA to fund these two spending projects that there is no money left for the hardware required for space exploration.
If these two make-work projects can be de-funded, here's what I think the funding priorities should be:
1. Assist SpaceX with completing development of their flyback rockets to reduce the insane cost of getting to LEO
2. Initiate a deep space transit vehicle program that provides some measure of artificial gravity for extended duration missions
3. Properly fund closed loop life support development
4. Start work on a man rated SEP propulsion stage for the deep space transit vehicle
5. Properly fund development of EDL technologies required to land on Mars
If we are ever to extend our presence beyond Earth, I believe these technologies are required to achieve that goal.
One of the biggest reasons we can't afford to explore is the staggering cost of launch services. To this day, with all the billions spent on affordable launch vehicles that never came to fruition, NASA is no further along than when it started. SpaceX is the only launch services provider to date that has devised a method to return launch hardware in working order.
With SLS, even if the wildly optimistic launch cost of $500M was achievable (the contractors will ensure it never will be), for the same money we could have launched F9H five times and lifted 265t to LEO instead of 70t (90t-95t if we had an upper stage that there's no development funding for). If launch costs for SLS are nearer to a more realistic $1B, then the mass differential is even more lopsided in F9H's favor.
Any transfer vehicle or lander vehicle solution devised should be required to meet weight restrictions of reusable launch vehicles such as the SpaceX F9 and F9H. This necessarily means orbital assembly and multiple launches, but the solution meets criteria #1 for space exploration, which would be feasibility within NASA's existing budget while simultaneously freeing up money to fund development of all the other technologies required for space exploration. Would it be cheaper to develop a wider payload fairing for F9H or continue with this SLS nonsense that's sucking the life out of NASA's manned space flight program?
The point to all this is that any transfer vehicle or lander solution that involves a vehicle so heavy that it requires SLS for a ride to LEO should simply be written off as impossibly expensive and therefore not feasible. Although I've been accused of working for Boeing or Lockheed-Martin over this point of using smaller descent/ascent vehicles on Mars, that is precisely why I want smaller capsules. I want something that is feasible with reality based budgets instead of money from heaven or a development program that is delayed for a decade or more that will, in all probability, never occur because this or that political group will remove or squander funding for it.
SpaceNut,
The Phoenix lander is a good analogy for weight. I would use a HIAD and parachute combination for EDL. These are technologies that can be tested here on Earth and later on Mars, when the tech is ready and funding is available. We could reasonably afford to send a half dozen instrumented micro capsules to Mars using a single F9H and land them at different locations to determine what our limitations are. More importantly, we could test our ability to precision land micro capsules near a beacon so we can avoid development of expensive multi-person landers with weeks of supplies aboard. The money saved by not developing multi-person Apollo style landers would be better spent on the MTV and Mars surface habitat modules landed using a larger HIAD or ADEPT.
If we want to do this at all, we're going to have to focus funding on technologies that are absolutely required to land humans on Mars. Small capsules and return rockets will work just as well as larger landers for the task of Mars descent/ascent for humans. I would love for NASA to have funding to build and launch multiple large, multi-person landers. The funding is simply not available and won't be in the near to mid term because of Orion and SLS. There won't even be money to use SLS on a regular basis, which is why everything I propose uses F9H.
Everybody keeps talking about sustainable space exploration using affordable solutions, but nobody seems to actually want to do that. Affordable looks markedly different from what we're doing now. NASA is busily trying to re-create the Apollo program because that's the only program anyone remembers that seemed like a success. From a goal achievement standpoint, it was successful. From an affordability standpoint, it was a total disaster.
We now have a capsule that's heavier than Apollo that uses a rocket that's somehow less affordable than Saturn V was and doesn't have Saturn V's capability. If humans ever fly on Ares V Lite / SLS, the development program for the damn rocket will have run for longer than the Saturn V program. Do we really need an equally unaffordable multi-person lander to go along with that?
Yes you are being Debbie Downer. Read the documents. No, it hasn't flown. But it's way past PowerPoint. They've built hardware and tested in a ground lab. That's way beyond any work on an inflatable heat shield. Besides a Balloot is an inflatable heat shield for aerocapture; it isn't good enough for direct entry into the atmosphere of Venus or Mars. That's the two destinations the team for ADAPT are targeting. The Mars Direct mission plan included a heat shield that could be deployed like an umbrella. ADEPT is exactly that heat shield, designed for payloads heavier than Curiosity. Their document states it's capable of atmospheric entry of a payload heavier than the Mars Direct habitat or ERV; so it's more than enough.
Rob,
NASA has developed inflatable tech a little beyond powerpoint, too.
So you're saying a technology NASA is currently working on and making progress with is not ready, but inflatable heat shields that have had no work what so ever are somehow ready?
Inflatables have flown several times now and all tests I am aware of that didn't suffer from a launch vehicle failure have been successful.
Has ADEPT ever flown? Ever? Or is it powerpoint tech with some materials testing behind it? I'm not trying to be a Debbie Downer, but I'm pretty sure that they're still in the feasibility phase with ADEPT.
Oh, sure, I would like to double NASA's budget and slash the military budget. In year 2000 I said we could slash the military budget by 10%, give half to NASA and the other half for tax cuts. That would double NASA's budget. But it didn't happen. But after George W. Bush, utopia would be to cut the military budget to year 2000 plus inflation. Remember, year 2000 was the last year America had a balanced budget. In year 2000 the military budget was $288 billion, but in year 2007 it was $700 billion, and 2008 it was $799 billion. For year 2009, the first budget approved by Obama, it was $901 billion. This raises the obvious question "Are they insane!?!?!??!" And some people wonder why America is broke. It's been cut a bit; for 2015 it's only $628 billion. "Only!" If you take the year 2000 military budget and apply inflation to today, it works out to $390.87 billion. So try doing that. Try telling Congress to stop waging war on the Middle East, slash the military budget to that level, and double NASA's budget. Good luck with that.
Yeah, I'm dreaming, I know.
Actually, I was thinking of something much smaller and lighter. The micro capsule and service module would weigh between .5t and .75t. The capsules aren't loaded with crap that's not required to get astronauts to the surface of Mars. The MTV assists by forcefully ejecting the micro capsules from the swash plate.
I think ADEPT is an enabling technology for landing the larger and heavier payloads, like the habitat modules or mobile habitat modules (rovers) on Mars, but let's admit to our reality and concede that this is a very new technology that will require far more testing before it's ready for prime time.
If NASA's manned space flight budget was double what is now, which is what I think a proper level of funding would be, then we'd have sufficient funding to develop the kinds of technologies we'd really like to have, such as multi-person landers, deep space transit vehicles, closed loop ECLSS, and active radiation shielding.
Regarding the presentation, I think approach #3 is the correct approach, even if it gives up a little payload mass in comparison to approach #4, by using more propellant for supersonic retro-propulsion.
I was thinking about using an inflatable heat shield to assist with deceleration and an aluminum alloy or composite capsule. Although my MTV concept is detailed in another thread, I was thinking that four of these micro capsules would be locked into spring loaded launch rings on top of the swash plate. After the MTV spirals in to LMO, the capsules are manned by suited astronauts to land on Mars. The capsules have a clamshell design. To use the capsule, the astronaut unlocks the service module, moves it out of the way, enters the capsule, reattaches the service module to seal the capsule, and then straps into the fabric seat. This should be an easy task in microgravity, even in a suit.
The capsules are exceptionally simple and have two primary components.
1. Capsule - contains the astronaut in his/her pressure suit on a fabric seat bungee corded to the walls of the capsule. The astronaut's suit contains the avionics to process sensor input and the helmet contains a display. There are three manual controls in the capsule, attitude control, a pull ring to activate the inflatable heat shield, and a pull ring to release the parachute.
2. Service Module - contains enough storable propellant to de-orbit the capsule and maintain attitude during the initial stage of reentry, a battery, a basic sensor suite to feed information to the avionics, the inflatable heat shield, and the parachute. Just like HIAD, the SM will shift the weight of the astronaut to steer towards the landing beacon.
The advantages to this approach are that a failure of any one capsule does not mean an instant end to the mission, which is what would happen if a multi-person lander failed during descent, the technology to land payloads that weigh 1t exist today and have been tested on Mars, and that the development and testing program would be affordable.
Ideally, after landing on Mars the astronauts would use a light truck to carry the capsule and service module to a fueled ascent rocket, launched ahead of the astronauts and fueled on Mars using ISPP, attach the capsule to the top of the rocket, and then use the capsule to return to the MTV after the surface mission has been completed, meaning each astronaut has their own ride back to the MTV. The capsule components are so small and light that the astronauts could assemble the capsules atop the rockets with wire ropes and pulleys. If one capsule fails to reach orbit, the entire mission isn't an instant total failure.
The general idea is to keep every aspect of LMO/Mars/LMO human delivery as simple as we can possibly make it. For critical functionality like descent/ascent, small and simple is better on Mars.
I've said it before, but I'll say it again. Start really small. Single person landers are about working with realistic budgets and using existing technology, not giving up on something better.
Money isn't going to fall from the sky to fund heavy lift launch systems and multi-person landers. Absent angel investors with pockets like the Marianas Trench, the kind of money needed to do the types of things we want to do with lander tech just doesn't exist right now or the near future. NASA and Congress squandered available funding on SLS and Orion.
If we're going to pour money into a development project, let's start with the MTV and its propulsion system. Let's design something that F9H vs SLS can lift, even if it has to be assembled on-orbit.
If there's any money left, closed loop ECLSS and active radiation shielding are higher priorities than insanely expensive landers using experimental reentry tech. NASA had its shot to save the lunar and Mars programs by funding a lander program instead of a redundant capsule program.