Thursday, December 17, 2015

Landers again

At risk of beating this topic to death...
This write-up is quite a bit different from my earlier Ceres proposal, but I think it would achieve the same objectives.

 NASA stands to gain significantly in the upcoming omnibus spending bill, as reported by SpaceNews. Space technology continues to get the shaft, while SLS and planetary science get boosts. Overall the agency is set to receive $756 million more than requested, for an overall award of ~$19.3 billion. Much of that is earmarked for specific projects. Most specifically, $175 million is earmarked for design of a Europa mission with a lander.

 Let's assume that this modified Europa mission will be roughly New Frontiers-class ($750 million to $1 billion). The design and development costs for the program will be finely-tuned to this one mission's requirements and eat more than two-thirds of the cash. The one-off flight hardware will be quite expensive. It will probably meet its primary and secondary objectives and return a lot of good science data.

 Instead of following this process, what would happen if we handle the design and development as a generic outer-bodies exploration vehicle program leveraging experience from the several successful deep space probes NASA has already fielded, most recently New Horizons?
 Consider the MCSB (modular common spacecraft bus) as a model program but scale it into the 20-40 ton fueled mass range, sized for an Ariane, Delta IV Heavy, Proton, Vulcan or Falcon Heavy main payload or as an add-on payload to an SLS launch.

Monday, December 14, 2015

Earthside - Rubble-eating block factory for disaster cleanup

These people have noble aims, but some unfortunate name choices.

The Mobile Factory is a project to build rubble processing and block forming equipment into shipping containers which can be deployed at disaster sites, primarily earthquakes. Local residents whose homes have been destroyed can operate the equipment, bringing in mixed rubble for sorting and processing and then casting construction blocks from the results. The blocks are meant to be used in the construction of earthquake-resistant housing, no mortar or rebar required. (Bamboo serves as vertical reinforcement.)

They have a nice user's guide that manages to express the workflow without words.

Unfortunately their site is very light on details like how exactly we get from fully-set concrete rubble to recast concrete blocks. I recommend the Reuters article about them from summer 2015. They describe their blocks as "shaped just like LEGO", which is a bit like taunting the lawyers at IBM. They also have named the blocks themselves Q-Brixx, a name that appears to describe ruggedized portable testing equipment from Gantner.

All of that aside, this is a project with functioning equipment and a demonstration plot, plus significant industry, NGO and government backing. Evidently their process works.

 I think this is a technology that might (and that's a big might) be applied to block formers intended for Mars or Luna. If done properly, a program under NASA (for example) could take this project's equipment as a starting point then automate and optimize. Equipment would be tested alongside the manual version at actual disaster sites, and the two projects could share information and design refinements.
 The aid project would benefit from additional resources and participation at disaster sites, and may see design improvements as a result. The space agency would be able to start from a working manual design and could make and test changes on Earth in a way that benefits people harmed by disasters. At some point the designs will probably diverge, but if the starting point is equipment that works in and is operated by an earthquake-ravaged community then rugged reliability and simplicity will be built in from the start.

 I only wish I knew more about their process. Perhaps it is as simple as using crushed and graded rubble as aggregate, then adding in new cement to form concrete blocks.

Friday, December 11, 2015

Public-private Ceres lander

My previous post on Ceres suggested landing a batch of payloads on the surface as a proof-of-concept mission for hardware intended to explore icy moons like Europa. Let's look at the numbers.

 I will assume launch service is a single Falcon Heavy to LEO, maximum payload 53 tons at a cost of $150 million (slightly above recent prices). According to Project Rho, the dV required is 4,739m/s to make orbit and 320m/s to land.

In short, my estimate of five Europa-sized payloads seems reasonable. Costs should be in the $1.1 to $1.4 billion range, with much of the development costs applicable to the actual Europa lander and follow-on icy moon landers. In fact, I think putting a lander on every major moon of the solar system except Io could be done for less money ($10-$14 billion) than a single manned Mars landing ($20-$200 billion). Even allowing for 50% cost growth that's still around $21 billion over perhaps 20 years, not a dealbreaking increase to NASA's budget.

Full details after the jump.

Ceres has ammonia-clay surface soils?

A (very) recent Nature paper suggests that Ceres has ammoniated phyllosilicates in the surface soil. (That is, nitrogen-bearing clay). The authors use infrared spectrum matching, a proven* technique.
(thanks to The Dragon's Tales for the link.)

 This is a big deal. It means Ceres has abundant quantities of carbon, nitrogen, oxygen and hydrogen, much of it already in the form of organic molecules. We already know* it has a liquid water layer under the icy crust. It appears to be very similar to a CI chondrite, so there should be sufficient amounts of the other minerals required for plant life.

 This makes Ceres a desirable destination for mining. With only 3% of Earth's gravity, moving huge amounts of material is fairly cheap. There is abundant water, carbon and nitrogen available and in easy to handle forms. It is the closest low-gravity body to Earth with proven water reserves and by far the closest such body with nitrogen reserves. (Most nitrogen we know of or predict is far enough from the sun to be nitrogen ice and far enough from Earth to take decades to retrieve.) Transit to and from Ceres is a long journey (2 years 7 months round-trip for short stay, 3 years 10 months for long stay), so this is likely to be an automated process. Still, this is going to be a much cheaper source of nitrogen (for breathing gas and fertilizer) than Mars or Earth if done properly.

 This also makes Ceres a desirable destination for scientific exploration. There have been rumblings lately about a mission to Europa to look for life. Ceres has 22% of Europa's gravity, enough sunlight for solar power, a shorter travel time and only normal radiation levels (vs. Jupiter's hellstorm of invisible death). With launch windows every 1 year 3.3 months and travel times (via Hohmann transfer) of 1 year 3.5 months, science returns will occur rapidly. (Jupiter's one-way trip is about 2 years 9 months and launch windows are every 1 year 1 month, so a Ceres mission is 16 to 18 months shorter.) The delta-V to Ceres is about 9.5km/s to orbit and 0.3km/s to land while Europa is about 25.2km/s to orbit and 1.4km/s to land. Equipment meant for exploring the outer icy moons could be tested at Ceres under less hazardous conditions and for less money. For the cost of one Europa mission we could send about five similar payloads to Ceres for competitive testing, not to mention the science return and the add-on opportunities to observe other bodies in the asteroid belt (perhaps including one or more permanent telescopes in orbit around Ceres).

 * The word "know" represents more of a sliding scale. Until we have actual samples of these compounds taken directly from Ceres we will not know for sure. Until we drill a shaft and see actual liquid water, again, we cannot be 100% certain. Still, given the evidence at hand these conclusions appear to be sound and sufficient reason for a Ceres lander to collect this evidence.

Wednesday, December 9, 2015

Menu planner update - now with peanuts

 I spent a few hours cleaning up my menu spreadsheet. The biggest change is the addition of peanuts, oats and barley. I also changed the default settings to eliminate beef, pork and dairy in exchange for peanuts. Oats, it turns out, are a terrible choice for food production: an embarrassing 1.5 grams per m² per day and 1.1 kcal/m² per day. Sweet potatoes and squash achieve more than 90 times that calorie yield.

 The upshot is I have a much healthier reference diet, but it takes about 12.6m² (50.4m³) per person rather than a bit over 9m². That's still only a third of the usual assumed area, so I'll take it. One important consideration: I use 4-meter heights for my hydroponic areas. A 3-meter height requires about 16.7m² (50.1m³), while a 2.5-meter height requires about 22.6m² (56.5m³). Shorter spaces lead to inefficient packing of shelves, so improvements over my crude method could be made. These numbers could be verified using vertical farming techniques and facilities on Earth today. (I should write a grant proposal...)

 Peanuts have an incredible impact on a planned diet. They are high in protein, fiber and good fat. They have low mass yields (18 grams/m² per day) and calorie yields ( 107 kcal/m²/day), but the protein:fat:carb balance is overwhelmingly pointing in the right direction for a grain- and vegetable-heavy diet.
 Evidence shows that a diet that includes nuts (any kind, even peanuts which are technically legumes) improves heart health, lifespan and to a lesser extent quality of life overall. Using even a small amount (less than one serving per day) allowed me to eliminate beef and pork as protein sources, dramatically reducing saturated fat and improving overall macronutrient balance.
 On the other hand, due to low yields even a small amount of peanuts requires a large amount of space; about a third of the growing area would be peanuts and another fourth would be barley and wheat. I would like to see if peanuts can be trained for continuous production since they are indeterminate plants; this could significantly increase yields.
 For every 2kg of shelled peanuts, 1kg of shells is produced. These are ideal for hydroponic media (after crushing) for root crops like peanuts, carrots and potatoes, as well as for seed-starting plugs.

 Perhaps surprisingly, eliminating animal protein from the diet actually increases the area required to feed a person. This is because the animals are fed harvest waste; they may process their calories inefficiently, but they are calories that would otherwise have gone to waste. As a result I increased servings of eggs, chicken and fish somewhat to use the available biomass effectively. The overall efficiency was about 1 kg of edible meat per 5kg of biomass, with 1kg of biomass produced per 2kg of edible plant mass.

 It doesn't look a whole lot like my present diet. People would be eating a whopping ten to fourteen 100-gram servings of vegetables and leafy greens pretty much every day. Animal protein makes up about three servings per day, two of them as eggs. Grains make up about another three servings, while sweet potatoes and related starches weigh in around two servings per day. Overall the diet ranges between 1.75kg/day (children) and 2.38kg/day (men), lots of volume, lots of fiber. One can also see how much additional water is required: about 2.2L for men, 1.2L for women and 0.9L for children per day. It might become common to eat four meals per day, or at least the traditional three with frequent raw vegetable snacks.

Monday, December 7, 2015

Long-term plan: large modular habitats

 I've made reference to plans for large-scale habitats before. It's time I write down the big picture as I continue the process of refining the details. The research I've been doing for this project has led to many of my posts here with information about radiation shielding, structural materials, agricultural yields and various life support systems. Perhaps that information will be more useful in context.

 There are several large habitats proposed, generally by people who are both smarter and better-educated than I am. Wherever possible I prefer to use solutions proposed or developed by others, but I disagree with some of the fundamental assumptions made for structures like the O'Neill cylinder. That will necessarily result in a different outcome, thanks to several design decisions that go in another direction. #1 on that list: There are no windows. None. Don't even think about it; windows in space are incredibly stupid.

 This will be a large post, so I'm continuing after the jump.

The headline results so far are as follows:
Design population: 5,000 people
Maximum population: 5,280 without major changes, up to twice that under emergency conditions
Mass: 142,750 tons shielding, 4,552 tons hull, 2,770 tons air, 350 tons occupants. As-yet unknown masses for furnishings, life support, hydroponics, other systems.
Volume: 2,262,000 m³ (79,882,000 ft³)
Area: 138,000 m² (13.8 hectares / 34 acres) under habitable gravity.

The structure would require the capture and exploitation of 160,000 to 200,000 tons of asteroidal material, or about 67,000 m³ of carbonaceous chondrites. Only about 600 tons (0.3%) needs to be carbon, but nearly 2,000 tons (1%) needs to be nitrogen. A single 50-meter diameter rock should just about do the trick, roughly the size of the Tunguska meteor. An alternative is sixteen 20-meter diameter rocks (Chelyabinsk sized) with the proper composition on average. There are anywhere from hundreds of thousands to tens of millions of near-Earth asteroids in this size range.

Thursday, December 3, 2015

SeaLaunch appears to be for sale

Hat tip to the Dragon's Tales for the link.

 Roscosmos and RKK Energia are reportedly looking for buyers or investors in the Sea Launch project, due to the high cost of ongoing maintenance. Said maintenance amounts to $30 million per year for the purpose-built command and integration vessel and self-propelled platform.

 Sea Launch is a joint venture between Norway, Ukraine, Russia and the United States with Boeing initially as managing entity. The project launches payloads to equatorial orbit using Zenit rockets on a specialized floating launch platform. After a bankruptcy in 2009-2010 controlling interest was acquired by a Russian company. Due to Russia's invasion of Ukraine the project ceased operation in 2014. In September of this year Boeing won a judgement in court related to costs of the 2009 bankruptcy filing, which makes possible a judgement of up to $356 million.

 Politics aside, the Sea Launch model has many advantages. Payloads go directly to equatorial orbit, increasing the mass to GEO by significant amounts. I see it as a 'toes in the pond' approach, a precursor to the 'dive-in' approach I describe here. I'm particularly pleased to see my maintenance estimate is twice the (rumored) actual maintenance cost for Sea Launch, which is exactly where I wanted it to be.

 Most of the players in commercial space development are well known and their die is cast, but who knows... maybe there's another billionaire out there willing to buy this hardware on the cheap and get creative with it.

Tuesday, December 1, 2015

Lunar circumferential railway

This is a followup to the last earthside post about arch-lock, looking at longer-term uses for the equipment on the moon. While I think it's more likely that we would build tramways using tensile towers and tether technology, this (relatively) low-tech approach could be started within a few years, without any radical advancements and with fewer leading 't's.

An example late-stage use case would be connecting a Lunar polar base to the equatorial L1 or L2 tether anchor sites. Read on for details.