Author: Adam

Human/Bacteria Hybrid Emortals

Found in nature’s freezer, the secret of living to 140 | Mail Online.

Certain bacteria and/or their by-products when injected into mice & flies (standard lab-animal models for such studies) extend their healthy life-spans by almost double. Thus the headline about humans heading to 100-140 years of age as normal. Rapid advancements in reprogramming the body’s natural stem-cells to become fully pluripotent and this newly discovered bacterial longevity, combined with tissue engineering of organs (eg. lungs made on demand, as recently demonstrated), suggests that human longevity might be feasibly pushed to +150-200 years.

Where would that get us in the Galaxy? Speed is of the essence for distant targets, but nearby stars become accessible if 100 year trip-times are acceptable for a crew. Assuming 0.1-0.3c are reasonable cruising speeds, then targets 10-30 light years distant come within reach. That’s literally hundreds of possible destinations, as the RECONS and SolStation websites describe in some detail.

Another recent find is the possibly inducible suspended animation that some people have experienced to survive extreme circumstances, most spectacularly the case of a Japanese man who lay on a hillside in the cold for 23 days without food or drink. Oxygen restriction, at a cellular level, seems to cause cells to switch into the “slow state” and survive periods of extended low metabolism. Could this be used to extend the effective lifespans of starship crews? My mind boggles at the possibilities, but the need for very brave test subjects to explore the fringe between life and death sobers one’s thoughts. Eventually we might see starships full of hardy emortal (“extended mortal”) colonists venturing into the Deep Cold between the stars, their ships seeking out a new life in the warmth huddled close to the stars.

But the Deep Dark Cold between the stars might be worth inhabiting too. Recent modelling of the formation of the Oort Cloud implies many comets are born, then thrown loose from the stellar nurseries where stars are formed. The Galaxy might have an Common Comet Swarm surrounding all the stars, providing potential habitats for those unafraid of the Cosmic Dark. While they might get energy from fusion, collecting starlight with huge soap-bubble thin reflectors might provide enough energy for sustaining life indefinitely.

E-Eyes on the Cosmos

New Horizons, the fastest launched probe, is shooting towards a close encounter with Pluto and its three moons on July 14, 2015. As NH will get ~50 metre resolution we can work out the baseline for an interferometer to achieve the same. In visible light, say 0.5 micrometers, the limit of distinguishable detail 50 metres apart needs an aperture of 61,000 metres for Pluto’s distance of ~5 trillion metres. So a near-term interferometer won’t see Pluto better than the probe, not unless the scopes are really, really far apart and their optical signal can be combined as a virtual interference pattern to analyze. A challenge, and though there’s nothing unphysical in the idea it’s not happening soon enough to beat New Horizons.

The planned European Extremely Large Telescope, a massive telescope with a 42 metre wide mirror, will show an image of Pluto about 32 pixels wide, if the pixels are packed to the optical limit. That’s pretty good for a planet so far away. Two E-ELTs 200 metres apart would increase that to ~160 pixels or so.

What’s the extreme of performance possible?

Since 1995 there’s been some NASA discussion of a Exosolar Planet Mapper able to produce ~100 pixel images of Earth-like planets up to ~10 pc away. At that extreme, some 300 quadrillion metres away, an Earth-like planet with a ~130 km resolution needs a telescope some 1,400 km wide. While it’s tempting to say an interferometer that big is doable since radiotelescopes have been combined in bigger interferometers there’s a major problem. The photons reflected off the planet have spread themselves far and wide across an immense spherical wavefront. At 10 pc 1 square metre of reflecting surface of the planet has had its rays spread over ~2.1E+21 square metres. Each photon now has ~2 square metres to itself. To get a decent signal we’d have to catch a lot of photons with a lot of telescopes and keep extraneous noise out. Tricky.

Nuclear Power Forever*

*for more years than you can count at least.

Interesting discussion of nuclear power as the climate change solution… Nuclear FAQ

The point I want to look at is the claim that there’s 220 million years worth of Uranium & Thorium for a 10 billion terrestrial population at US energy usage levels, in the top 4 Km of crust. Consider the erosion rate of the continental crust – some 7 gigatons per year. In 220 megayears some 1540 quadrillion tonnes of rock will have eroded into the sea – 570 quadrillion cubic metres at an average density of 2.7 tonnes/cu.metre, which on 150 trillion square metres of surface is a layer 3800 metres thick.

Thus, to get at the Uranium/Thorium we don’t have to mine anything but the oceans.

SpaceX & Iridium NEXT

Cosmic Log – Next stage ignites in the rocket biz.

Alan Boyle, Science Reportage Guru at MSNBC, discusses the new deal between SpaceX and Iridium, the Satellite telephone provider. Great news for SpaceX and hopefully bargain basement rates for space-launch for Iridium. Will be very interesting to follow the progress of both and to see if any other rocket-firms are going to make a move on providing cheaper space access.

Of course my hopes are that SpaceX will both achieve cheaper access to space (CATS) and achieve a (mostly) reusable launcher vehicle (RLV) in the form of the Falcon series. The first stage wasn’t recovered on the first successful orbital mission for Falcon 9, but I believe Musk’s avowed commitment to the concept.

But just how low can the price go? At ~$5,000/kg to orbit the price of space access isn’t cheap, even with SpaceX. As their experience base expands I think Musk & the boys will get closer to $2500-$1000/kg prices, if the demand is there. At such rates the prospect of commercial flights to the Moon arises.

How much would that take? Consider the Falcon 9 Heavy and the Dragon capsule. Fully tanked the Dragon masses 8 tons and the F9H can orbit 32 tons of payload. If we modify the second stage to be both launcher and fuel tank, then I estimate some 34 tons of propellant can be orbitted. Assuming a total mass of ~36 tons for the modified stage that means a total mass of 44 tons and a mass-ratio of (44/10) = 4.4, enough to give the Dragon a delta-vee of 4.97 km/s – more than enough to get to a low orbit around the Moon and back, assuming aerobraking return for the Dragon capsule.

Of course the real questions are: what do we do when we get there? What would it take to actually land? A Bigelow station could potentially be placed in Low Lunar Orbit, but access to the surface requires a delta-vee of 3.6-4.0 km/s. That’s a lot of propellant to be sent up from Earth. If propellant could come up from the Moon, then a landing vehicle could be operated for repeated missions. We know there’s water on the Moon and potentially something to burn. Of course we could use hydrogen from electrolysis, but it has issues due to being a deep cryogen. Liquid oxygen, the quintessential cryogen, is easy by comparison. Rockets can use powdered aluminium and LOX mixed together, which forms a stable semi-solid propellant. We know there’s aluminium on the Moon, but extracting it takes serious energy.

Some inventive rocket engineer will think of something…

Addendum: I forgot to add that powdered aluminium in water makes for a rocket fuel too. However both Al/LOX and Al/H2O produce non-volatile exhaust products that can’t be recycled like water can. Water vapour has the advantage that it will be retrapped in the Moon’s cold-traps, thus a reason to be very careful in our use of those areas. Cryogenic cold this close to the Sun is a hard thing to sustain – having it for “free” on the Moon is nothing to waste.

Space Based Solar Power II

Ground-based and space-based solar power, in spite of certain misconceptions, shouldn’t need to compete because they’re optimal for two different energy markets. Consider ground-based solar – its peak output is during the hottest part of the day, when the Sun is bright and high in the sky. But it’s at its worst when low in the sky (and at night, of course) and during the colder seasons. Space-based is good all-day round, all-year round… BUT it’s hard to up the output. That’s especially needed when the Sun is high in the sky and the ground-based solar is working hardest.

Couldn’t ground-based cover both by more collectors being on the ground to make up for low-light and night conditions? Let’s look at that proposition in some detail. How is power stored? If we assume batteries then we’re faced with some difficulties – firstly a top lead-acid battery, with a supercapacitor to help, is only able to store 75 W.hr/kg. Say a household needs 3,000 W averaged over its whole day – and we’re assuming the car is being charged by the power system too. That’s 40 kg of battery per hour of supply, some 960 kg of battery for the 24 hours in the day. And batteries have a discharge efficiency of 80-85% – meaning we need a total of 1,200 kg of batteries to store the day’s energy needs.

But how much day have we got to collect the energy from the Sun in? At best it’s about 0.25 of the day – thus 3,000 W continuous supply needs to be fed by 15,000 W of solar collectors (remember that battery inefficiency.) Thus at $0.5/W our “Total Power” solar-power system costs ~$7500 of solar array plus all those batteries (~100 total, costing ~$15,000, plus the power handling system ~$5,000.) Thus our system costs $27,500 on the optimistic side of costing, since there aren’t any $0.5/W solar collectors on sale. The system would recover costs in ~5.5 years at ~$0.2/kW.hr from the energy retailers. Assuming its output didn’t decline over time that is…

But what about space based solar? Firstly it doesn’t need storage – it can supply all the time. Of course not everything is being used “all the time” but with a decent amount of homes with some level of power storage and the excess could charge those, drawing back when it’s peak time. Honest retailers might even reduce the “consumers'” bills in exchange for the storage service. So no storage. No battery costs. However the collectors need to be ~1/6th of what’s needed for the same continuous output on Earth. And concentrators, rather than flat panels, can be used all the time. Expensive, ultra-efficient cells can get 500-1000 times the sunlight of their terrestrial counterparts and convert at 40-65% efficiency…

Towards nanowire solar cells with a 65-percent efficiency

Published on: 16 June, 2010

TU/e researchers want to develop solar cells with an efficiency of over 65 percent by means of nanotechnology. In Southern Europe and North Africa these new solar cells can generate a substantial portion of the European demand for electricity. The Dutch government reserves EUR 1.2 million for the research.

…thus immense savings in materials and array mass. My rough BoTE computations suggest a 1 GW SPS can mass 1,400-720 tons, with huge savings in launch costs. Assuming we’re launching via Falcon 9 Heavies that’s 72-36 launches. Elon Musk would love us!

So instead of spending ~$7,500 on 15 kW of array per household, only ~$1,250 is needed. And no batteries. Thus, potentially, a BIG saving overall. But some extra panels for peak power usage – in the bright, hot part of day – and there’s a neat synergy between the two power supply sources. Of course that’s all evened out over ~1 GW/3000 W households (~333,000) as individual supply isn’t so easy to do with a SPS.

However initial demonstration SPS units might only provide a few MW, enough for small communities. In theory there’s no reason why a bunch of smaller sub-units can’t eventually be ganged together in a common structure and modern phase arrays used for sending out power-beams to several different rectennas on the ground. If 720 tons is 1 GW of supply, then a single launch demo SPS massing ~20 tons at GEO might supply ~30 MW to the ground. That’s enough for a 10,000 household township in a remote area. Worth considering.

Space Based Solar Power

How to Eliminate Future Catastrophic Oil-Spills.

(at Kurzweil.net)

Space Solar Power (or Space-Based Solar Power) is undergoing a revival of interest. An excellent introduction can be found at the National Space Society’s SSP page. The presentation is biased slightly against nuclear power. But one thing which I can’t disagree with is advantage of no radioactive waste – even the best nuclear reactor fuel-cycles produce some, albeit short-lived. I believe the two, SSP and nuclear, will need to be developed side by side to provide power for all.

So what will be needed for space-based solar power to be an energy source for all? Currently photovoltaics are very expensive, especially space-rated high-efficiency cells able to take the thermal stress for extended time periods. One approach to reduce costs is go ultra-light – thin-films are actively being developed, and some space-rated designs are heading for ~4500 W/kg of PVs. Alternatively the cloudlessness of space means concentrator systems, such as the graphic above, can be used all the time – mirrors can reflect onto a high-intensity collector. Some concentrator systems tested on Earth can operate in conditions equivalent to 400-500 ‘Suns’ intensity. Very handy if, eventually, the solar system economy has developed enough to place collectors in closer orbits to the Sun – 0.05 AU would give x400 intensity of sunlight.

Of course the major cost issue, in some respects, is access to orbit. SpaceX is promising space-lift charges to LEO of $4930/kg and to GTO (s/c up to 4,680 kg) of $11,000/kg. With the Falcon-9 Heavy able to orbit 32 tons to LEO and send 19.5 tons to GTO one wonders if the charge will be lower per kg. To get from LEO to GEO, rather than just using a chemical boost to GTO, a solar-electric propulsion system could be viable. A few years ago the first version of Powersat, Inc. proposed an integrated SEP/Power-unit system to deliver its ~10 ton sub-units to GEO. There were unaddressed problems with the design, but the basic idea is a good one. An optimised design might opt for the simplest Electric propulsion system – IMO the Helicon thruster, which makes up part of Ad Astra Corp’s VASIMR. No electrode erosion issues and high-thrust for high Vex.

If we can get the cost down to ~$5000/kg then what would the cost of power be? A 1 gigawatt system needs a collector surface big enough to capture enough light to make up for system inefficiencies. The old SPS studies in the 1970s concluded that the energy transfer efficiency from the PV output to the Power-Grid on Earth could be ~63%. If we assume concentrators with ~40% efficiency, then the system efficiency is ~25.2%, meaning we have to intercept 4 GW of sunlight to get 1 GW of power to the grid. The year averaged level of sunlight is about ~1350 W/m2, so the area of the collector/mirror system is 2.94 million m2, a square about 1715 metres on its edges, or two circular collectors 1368 metres in diameter each. Obviously it’s not going to launch all at once – the Powersat concept sent thousands of sub-units up to gather together to be combined automatically. If the collectors mass 1 kg/m2 and the rest of the system masses the same equally, then the total mass is ~5,880 tons. Delivery cost at $5,000/kg is $29.4 billion. Kind of excessive, but not utterly ridiculous for such a big space-based system. Clearly the way forward is system mass reduction. My 1 kg/m2 was deliberately excessive. What if we’re looking at 0.1 kg/m2? And $2,500/kg to GEO? Then the cost is ~$1.47 billion, perhaps double that for the whole system costs, including assembly.

Getting in economically viable territory. But let’s look at it from the other direction. How much could the power sell for? If we’re talking competitive with power sources on the ground then the cheapest cost for power is ~$0.04 /kW.hr. A 1 GW SPS (Solar-Power Satellite) provides 1,000,000 kW.hr/hr and might last ~30 years without major system replacements – call it 263,000 hours. Thus the wholesale energy market value is $10.52 billion at constant prices. No inflationary adjustment. End-users, like the suffering masses of my state Queensland, are paying $0.2/kWhr, thus an energy retailer would gather ~$52.6 billion in revenue over that period, non-inflation adjusted. So profits aren’t unimaginable for space-based power-companies to aim to achieve. Let’s assume space-lift is 25% total cost, thus the 1 GW SPS system has to cost ~$2.63 billion to get into orbit. That gives us a rough guide to the kind of mass-efficiency and space-lift price we want to see to make SPS a viable profit-making enterprise.

If SpaceX can come through with their promise of space-access that’s “x10” cheaper – roughly a factor of 5 cheaper than their current rates – then $2,200/kg to GTO means our 1 GW SPS needs to mass <1,200 tons. Possible? Some clever SPS engineer, no doubt, will “make it so…”

NB: The power-price to end-users is in $AU, which isn’t much removed from $US. Over there many states pay similar rates at $US.

Addendum:

According to T.A.Heppenheimer’s summary of different SPS construction plans, the idea of flying sections to GEO from LEO under their own power isn’t new…

The Boeing approach, discussed in Chapter 7, called for the powersat to be built in the shape of a single flat slab with transmitting antennas at each end. Power would be generated by silicon solar cells. The principal construction operations would be in low Earth orbit, where the construction base would build each powersat in eight sections resembling the leaves of a dining-room table. Each section (two of them would carry antennas) then would be fitted with ion-electric rocket engines and fly under its own power to geosynch. The ion engines would use electricity to eject atoms of argon at very high speeds, some 225,000 feet per second, to produce thrust.

Activities at geosynch would be strictly limited. Because each powersat section can produce much more power than it needs for the electric rockets, many of its solar arrays would be rolled up like window shades. The few crew members at geosynch would unfurl the arrays, causing the powersat sections to spread sail like a clipper ship. As each section arrived, at forty-day intervals, it would be joined to the others. A completed powersat would be activated by a ground station.

…notice the sensible power-limiting of the ion-drives, unlike the old Powersat Inc. plan which had a fully unfurled array. Where did the excess power go? That was never answered.

Life On Titan!

Hints of life found on Saturn moon – space – 04 June 2010 – New Scientist.

CASSINI News Bite

Something is eating acetylene and hydrogen on Titan! Ok, so it might be chemistry, bare and unadorned by the complexity that is Life, but the two missing gases are exactly what would be used by an exotic metabolism suited to the -180 oC temperatures. We won’t know until we go!

But just how will we get there? A new paper by Ralph McNutt describing one possible architecture is discussed by Brian Wang at Next Big Future. A flaw in his analysis, aside from its conservatism, is the curious concern over mission criticality of a magnetic shield failure against cosmic rays. However the main drive – a high-powered VASIMR – and the main power – a low mass nuclear reactor (probably MHD) – both will require years-long, continuous performance from high-powered magnetic systems. Why aren’t their failure as likely or unlikely as a magnetic shield? Cryogenic propellant tanks will need to be protected against micrometeorites, presumably by low-mass Whipple shields, so why can’t a cryogenic magnetic field coil system?

I just don’t get the logic.

What’s Wrong with Jupiter … again!

Cosmic Log – Something hit Jupiter … again!.

See Jupiter’s Great Black Spot

Just after astronomers figured out what ran into Jupiter last year, giving it a black ‘bruise’, something else has smashed into the big planet and has been caught on video!

Video at SpaceWeather.com

The previous impactor is believed to have come from the Hilda family of asteroids, but this time the cosmic pugilist is unknown.

Hat-tip to Spaceweather.com

Complexity, Creativity & Randomness

Random Reality § SEEDMAGAZINE.COM.

Marcus Chown discusses the information content of the Universe – what has pumped “information” into what began as a very simple world? Chown points out that ‘random’ sequences require more information to describe than ‘ordered’ & ‘repetitive’ sequences – think of vortices in swirling smoke versus the cubic perfection of salt-crystals. Thus ‘randomness’, at the quantum level, is the ultimate ‘source’ of information.

Doesn’t seem quite right does it? Perhaps the problem is that ‘random’ itself isn’t very well defined when we use the world. Often it’s synonymous with ‘unordered’, ‘capricious’ and ‘surprising’ – my son says “How random was that?” when struck by some surprising behaviour or event amongst his friends and in the news media.

‘Ordered’ & ‘perfect’ are also ‘repetitive’ and ‘predictable’ – in today’s world such things have a negative valuation amongst the young. Boredom – or the struggle against it – looms largest for them, whereas in previous ages ‘predictability’ – like a regular meal, bed, job and clothing – was something keenly desired and sought for.

‘Lawful’ & ‘predictable’ can co-exist in the quantum world with ‘random’ and ‘surprising’ – just because a certain quantum event is probabilistic, and thus intrinsically ‘surprising’, doesn’t mean ‘anything goes’. The evolution of the wave-equation of quantum systems is utterly deterministic, but absolutely precise pin-point prediction isn’t what it gives us.

Of course none of that explains where the ‘randomness’ comes from. I suggest we can replace it with ‘novelty’ or ‘creativity’ and get a more meaningful sense of what is meant. There is ‘novelty’ inherent in the World’s events, an irreducible ‘creativity’ that can’t be shaken out of the system of things, as much as some physicists would like it to. But I agree with Stuart Kaufmann – the world’s evolution is ‘open’ to novelty and creativity, and that’s a good thing, even a divine thing.