Robot Explorers: A Mars program for the 1970s 1966

Robot Explorers: A Mars program for the 1970s 1966.

Once upon a time there was a Red Planet covered in vegetation and maybe possessing some kind of animal life with an atmosphere perhaps 1/10th our own, made of carbon dioxide (which spectroscopes could see) and probably mostly nitrogen (which spectroscopes couldn’t see.)

In 1965 that hopeful illusion was shattered when Mariner IV flew past Mars and discovered an atmosphere of mostly carbon dioxide that was 1/10th of the hoped for 1/10th. All that was seen of the surface was craters and Mars suddenly seemed a lot more like the Moon, and a lot less like a home for life. After 1971’s Mariner IX orbiter the planet had regained some interest, but the damage was done – all the proposed Manned Mars Missions had been rejected and very few held much hope for Life. But, by the end of 1976, even the hope we had for microbial life was in doubt. An ambiguous single positive out of three different life-tests carried by the twin Viking landers meant if there was Life it was hiding.

Today, 33 years later, and more than a few probes and rovers later, we know there’s lots of water-ice, there might be out-flows of briny water briefly, and there was acidic ground-water long ago, but Mars still hasn’t revealed any Life to us. We’re reluctant to give up the Search, but maybe Mars really is dead.

Carnival of Space #93: From our own planet, to exoplanets – The Planetary Society Blog | The Planetary Society

Carnival of Space #93: From our own planet, to exoplanets – The Planetary Society Blog | The Planetary Society.

Carnival Time! Best pick – or most thought-provoking – is a strident advocacy of a Nuclear Pulse-Gun for launching massive cargo payload(s) to LEO and beyond at Brian Wang’s Next Big Future. Brian suggests we might need only one to kick-start the real space-age.

Sulfur as a liquid on Venus

Technical data for the element Sulfur in the Periodic Table.

According to this source the boiling-point of sulfur at 1 atm is 717.87 K (444.72 C) and its critical point is at 1314 K at 204.3 atm. Past that it’s a super-critical fluid – neither liquid nor gas, but a bit of both. We can use those two data points to estimate that at Venus’s surface pressure of 735 K the vapour pressure of sulfur is just 1.3 atm or 1.4% of the atmosphere at 100% humidity. That doesn’t seem too unreasonable and it indicates that large pools of sulfur would be quite stable after erupting from within. A hydrosphere of the stuff could form – if there was enough of it. Magellan’s SAR scanning of the planet didn’t show any dark patches that indicated RADAR absorbing masses of the stuff, but localised deposits might’ve been below Magellan’s resolution limits.

It might seem like an odd thing to focus on as a liquid, but it has been suggested both as a medium of life and as a molecular structural material akin to carbon. Certainly terrestrial life has uses for it and there’s no reason why a different kind of life might not find it as useful as we find carbon to be.

Frozen Fish and Astrobiology

Europa’s ocean is interesting. It’s most likely a liquid ocean, warm and very deep. Europa’s the second satellite out from Jupiter. The inner satellite, Io, is blazing hot; it has volcanoes. The other satellites are frozen solid. In between there’s Europa, which has a thin layer of cracked ice. If you want to find creatures living in Europa’s ocean, you can do it the hard way – send a huge spacecraft carrying a submarine, dig through the ice, then launch the submarine to explore the ocean. Or you can do it the easy way. We know the other satellites have huge numbers of craters from being close to the asteroid belt. So what happens when Europa is hit with a huge asteroid? It will splash out immense quantities of water into space. If there are any fish present, they will be kicked out and freeze dried, and you’ll find them orbiting around Jupiter. There is already a ring of debris orbiting Jupiter, but nobody has gone to see if there are any freeze-dried fish. It’s a clever way to explore.

Freeman Dyson here some years ago.

Space Based Solar Power Within a Decade?

New Company Looks to Produce Space Based Solar Power Within a Decade | Universe Today.

Space Energy Inc. is hoping to have a power generating satellite beaming energy back to the ground in 10 years, and a demonstrator launched in just a few years. A laudable goal which they seem to have no illusions about being an easy goal. Hopefully advanced concentrator arrays will be used because we’ll be butting up against materials supply issues if solar is scaled up to meet total electrical demand globally, now and in the future. Fortunately new semi-conductors are being investigated for their photovoltaic potential and some, like iron pyrite, are abundant.

Earthlike worlds within 30 lightyears

Boffin: Earthlike worlds within 30 lightyears of here • The Register.

Alan Boss, of gravitational instability fame, has published a book (The Crowded Universe) claiming, surely as headline catcher, that every sun probably has a habitable planet. Habitable NOT inhabited. Just how long a planet orbitting a Blue Super-giant would last is a moot point as I suspect he means “almost every star”, which means the 99.9% that are Class A or cooler. If so then there’s a hundred billion habitable planets out in our Galaxy alone.

However he’s a “Civilization pessimist” who seems to think Intelligence doesn’t persist long enough for it to cross paths with other Intelligence. That seems kind of futile and lonely to me…

No Infra-Cosmic Intellect can Know it All

Within Any Possible Universe, No Intellect Can Ever Know It All: Scientific American.

An interesting proof of the ultimate limits of knowledge for any Being within a system. Even a mighty Kardashev Type IV Civilization will face unknowns if trying to operate within the Universe. Of course that does pose the possibility of inter-Cosmic entities linking up multiple Brane-i-verses through the Bulk and knowing them to their fullest extent thanks to their transcendent vantage point. I’m not sure if that’s possible, but it’s as possible as it is not, due to our ignorance of the Bulk and its non-gravitational physics.

SKYLON in the News…

Cosmos Magazine has a news bite on SKYLON which reports older news about SKYLON and funding of an engine study by the ESA. Goods news, but no breakthrough. At least the word is out there.

Here’s something to consider: SKYLON’s development is likely to be roughly $10 billion. How does that affect price-tag for LEO services? If 30 SKYLONs are made and each flies 200 times before replacement, then the development cost divided over all those 6,000 flights is $1.67 million, or $139/kg. If 300 SKYLONs are built then it’s just $13.9/kg. That’s development cost, to which we add per unit cost, per flight costs, and fuel costs, then profit. SKYLON uses 66 tons of hydrogen and 150 tons of LOX for propellant, which costs ~ $250,000 total adding $20.8/kg to the bill. Then there’s vehicle costs incurred due to wear and tear of the components of the cryogenic system, SABRE ejector ramjets, landing gear, RCS and avionics every flight. I’m not sure what the best estimate of those would be, but let’s assume roughly comparable to the fuel costs. Thus the bill is up to $55.5/kg. If a SKYLON costs ~$200 million per unit – expensive jet-fighter value – then that’s $1 million per flight over its lifetime, which adds $83.3/kg. That seems excessive and might go down with large production volumes. Perhaps we can halve it. Thus SKYLON might cost $100/kg to deliver payload to LEO.

How much payload do 300 SKYLONs need to carry to LEO to drive costs down? All up they represent 720,000 tons of payload lofted on 60,000 flights. If a 1 GW SPS masses 3,000 tons, including the GEO delivery system for its subcomponents, then 240 GW of SPS power could be installed. To power the whole world to the tune of 24 TW then 30,000 SKYLONs making 6,000,000 flights will be needed. Larger LEO cargo vehicles would reduce this somewhat. The Star-Raker SSTO, designed in the late 1970s as a ramjet/rocket hybrid, was designed to deliver 120 tons per flight, thus reducing the fleet or the flight numbers ten-fold. Alternatively Space-Elevators may eventually be developed, but that’s totally dependent on materials and laser advances that are unpredictable. SKYLON, I would submit, can get the job done.