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Comment: Keeping it reasonable. (Score 1) 221

by AJWM (#47959989) Attached to: Secret Service Critics Pounce After White House Breach

Isolated event, and the guy was brought down. There'll always be a risk as long as their are fanatics or loonies who don't give any though to their own personal safety, but there comes a point of diminishing returns.

Suppose they hired 10 times as many Secret Service agents? That just increases the odds of one of them going bad and offing the President himself. (Not a likely event, but having 10x as many agents also means more chances of confusion in a crisis, etc, etc.)

Security is never perfect (wasn't there an incident some years back where an intruder wandered into the Queen's living quarters at Buckingham Palace?) That's one reason we have a line of succession -- it's not like the government collapses in the case of an untimely death.

Mind, given the choices of VP over the past few presidencies, that line of succession might actually be helping lower the odds of someone trying to assassinate the Prez.

Comment: Re:Blastoff From the Past (Score 2) 19

by AJWM (#47934037) Attached to: ULA and Jeff Bezos' Blue Origin Announce Rocket Engine Partnership
The basic aerospike SSTO design goes back to the mid to late 1960s with Phil Bono's work (and a couple of his patents), and designs by the Douglas (later McDonnell-Douglas) corporation (SASSTO, ROMBUS, Pegasus, Hyperion and Ithacus). Chrysler Aerospace (IIRC) had a similar proposal for the initial Space Shuttle studies. Boeing's "Big Onion" came a bit later, after O'Neill's 1974 "Physics Today" paper kicked off the whole L5/space colony/solar powersat thing.

The designs were revived in the 1980s by Gary Hudson and Pacific-American Launch Systems (Phoenix) and later by General Dynamics (Millennium Express --disclaimer, I helped name it) as their proposal for the DC-X competition.

Yes, New Shepherd was clearly influenced by all that (as have several others, including a Japanese suborbital test vehicle). The design makes sense for a number of reasons:

  • structure weight is critical for SSTO, and the closer you get to a sphere, the better your structure-weight to propellant-volume gets, hence the relatively squat shape
  • the rounded-cone shape makes a great reentry vehicle, with some maneuverability (assuming asymmetric mass distribution)
  • the heat-shield on the base serves to protect against engine exhaust on launch as well as reentry heating
  • aerospike nozzles are inherently altitude-compensating, so potentially more efficient

Of course there are downsides to the design too, particularly in terms of integrating the design so that it's light enough for SSTO, and starting and controlling the large number of thrust chambers (usually at least 16, some designs with 24 or 32).

Comment: Re:Knee-jerk reaction (Score 1) 33

by AJWM (#47897117) Attached to: Curiosity Rover Arrives At Long-Term Destination

It still met the pre-mission criteria for life. That the other experiments gave confusing results was a contributing factor to wondering if those criteria were correct.

There's some indication that those other experiments weren't sensitive enough to detect life signs even in Earth soil samples from places like the Atacama desert in Chile.

In 2003, a team of researchers published a report in the journal Science in which they duplicated the tests used by the Viking 1 and Viking 2 Mars landers to detect life, and were unable to detect any signs in Atacama Desert soil.[21] The region may be unique on Earth in this regard and is being used by NASA to test instruments for future Mars missions. The team duplicated the Viking tests in Mars-like Earth environments and found that they missed present signs of life in soil samples from Antarctic dry valleys, the Atacama Desert of Chile and Peru, and other locales.

In 2008, the Phoenix Mars Lander detected perchlorates on the surface of Mars at the same site where water was first discovered.[23] Perchlorates are also found in the Atacama and associated nitrate deposits have contained organics, leading to speculation that signs of life on Mars are not incompatible with perchlorates.


And speaking of perchlorates and the Viking biology experiments:

On 2006, scientist Rafael Navarro demonstrated that the Viking biological experiments likely lacked sensitivity to detect trace amounts of organic compounds.[36] On a paper published in December 2010,[25] the scientists suggest that if organics were present, they would not have been detected because when the soil is heated to check for organics, perchlorate destroys them rapidly producing chloromethane and dichloromethane, which is what the Viking landers found.


Comment: Re:Knee-jerk reaction (Score 5, Interesting) 33

by AJWM (#47895565) Attached to: Curiosity Rover Arrives At Long-Term Destination

"the proposal lacked specific scientific questions to be answered, testable hypotheses, and proposed measurements and assessment of uncertainties and limitations."

Sounds like the report was written by physicists, not geologists or biologists.

I figure "we're going to look around, crack open a few rocks and do some chemical analyses to see what's there" is pretty good science.

On the other hand I also wonder why in almost 40 years nobody has yet tried repeating the labeled-release experiment on Viking which tested positive per the pre-mission criteria for signs of life.

Comment: Re:LOL (Score 1) 213

by AJWM (#47895517) Attached to: Congress Can't Make Asteroid Mining Legal (But It's Trying, Anyway)

Who in their right mind was part of this Treaty to begin with? No one in their right mind.

Bear in mind that if the treaty dates to 1967, it was being worked on in 1966, possibly earlier. At that time, the US was seriously worried that it might lose the space race to the Soviet Union (who were still racking up "firsts" faster than the US), so there was probably an aspect of bet-hedging to it. (1967 was also the "summer of love", so, hippies, and height of the Viet Nam war, so, distraction. So yeah, not in their right minds.)

When the Moon Treaty (also known as the treaty on the useful pieces of outer space) reared its ugly head some years later, plenty of people loudly and vigilantly campaigned to avoid it being ratified. (The successful effort was largely led by the L5 Society -- which was quietly thanked some years after that by several foreign (*cough USSR cough*) nationals because they didn't want it either.)

Comment: Re:Asteroid value (Score 1) 213

by AJWM (#47895477) Attached to: Congress Can't Make Asteroid Mining Legal (But It's Trying, Anyway)

An article. Wow.

Try reading up on the parent bodies of meteorites -- we know of quite a few -- then look at the composition, particularly of e.g. siderites. (Sure, plenty of stony meteorites too, still typically ~20% iron/nickel.)

Not that much carbon, actually. Lots of iron and nickel, and significant amounts of e.g. platinum group metals (same columns in the periodic table as iron and nickel). Fortunately there is some carbon, because it turns out that one of the easiest ways to separate out the different metallic elements is through selective fractional carbonyl precipitation. (React the metal mass with carbon monoxide, heat the resulting gas to the specific temperature at which the specific metal carbonyl breaks down, then collect the pure precipitated metal and recycle the CO.) You definitely want to do this in space, metal carbonyls are pretty toxic.

Comment: Re:Great news (Score 2) 269

by AJWM (#47886719) Attached to: Massive Study Searching For Genes Behind Intelligence Finds Little

Yup. They assume a direct relationship between "intelligence" and academic achievement. There ain't.

While it's unlikely that someone with an IQ of 80 will go on to great academic achievement, there's no guarantee that someone with an IQ of 130 will either. Plenty of high-IQ folks who got too bored with school and dropped out, or sidetracked by something which caught their interest so that they neglected their studies, etc. Probably most high academic achievers have high(-ish) intelligence, but the reverse is not necessarily true.

And, as you point out, the variation could be to a number of genes with small effect rather than a couple with a big effect. Wonder if they correlated for genetic tendency to AD(H)D?

Comment: Re:But is it reaslistic? (Score 1) 369

by AJWM (#47789675) Attached to: Islamic State "Laptop of Doom" Hints At Plots Including Bubonic Plague

Actually, getting hold of bubonic plague is easier than you think. It's endemic amongst e.g. prairie dogs in the Four-Corners area of the US (where Colorado, Utah, New Mexico and Arizona connect).

Of course, that ubiquity means it'd make a pretty poor bioweapon, since it also means the medical infrastructure is equipped to handle it. Also, it's a bacterium, so it can be treated with antibiotics. (In the 4-Corners area, hantavirus is a more serious concern.)

To answer your original question, I'd say "wishful thinking" -- but the 9/11 attacks probably started out that way too.

Comment: Re:Telnet-based BBS. (Score 1) 635

by AJWM (#47789605) Attached to: Ask Slashdot: What Old Technology Can't You Give Up?

Your comment prompted me to try again. My account is still there!

Noise Level Zero (nlzero) is the heir to Byte Magazine's BIX (Byte Information Exchange) system from pre-web days. No official connection, but it uses the same CoSy software and many of the BIX regulars moved over to nlzero when Byte shut down the BIX system.

Still going, with recent messages, though of course nowhere near as active as BIX was in its heyday.

Comment: Re:if 1 drive full, raid. Dual read write armature (Score 2) 316

by AJWM (#47762873) Attached to: Seagate Ships First 8 Terabyte Hard Drive

Back in the day, my college campus mainframe, a Burroughs B6700, had (in addition to its more conventional "disk pack" drives) a head-per-track (HPT) drive. The disk was several feet in diameter and the whole surface was covered with read/write heads (they didn't need to move).

Can't find specs on the B6700 version, but here's a blurb about the older B5500 version (from http://www.retrocomputingtasma...)

The powerful advanced systems concepts of the Burroughs B 5500 are fully complemented by the revolutionary Burroughs On-Line Disk File subsystem. With its "head-per-track" design, the Disk File provides all-electronic access to any record throughout the file in an average of 20 milliseconds.

        File organization, programming, and use are simplified because access is entirely by electronic switching, with no moving arms, card drops, or the like. Each record segment is equally available regardless of physical location on the disks. Multiple segments can be transferred with a single instruction.

        Module size is four disks totalling 9.6 million alphanumeric characters of information capacity. Up to 100 of these modules may be used with the Burroughs B 5500, effectively extending the memory of the computer systems by almost a billion characters. Transfer rate is 100,000 characters per second.

Comment: Re: Nope (Score 4, Informative) 511

by AJWM (#47743643) Attached to: If Java Wasn't Cool 10 Years Ago, What About Now?

Back in my (pre PC) college days, COBOL was big in business but wasn't taught or used by anyone in the Computer Science department. If you wanted to learn COBOL, those courses were offered through the school of Business.

And APL was taught by the department of Mathematics, to the extent that APL packages were used in the statistics classes.

Computer science classes weren't about teaching programming languages (we probably went through a dozen or more, from Algol and assembler to Lisp and Simula and Snobol -- we were expected to learn them ourselves depending on the assignment), but about how to think about programming (and operating systems and so on).

The first Rotarian was the first man to call John the Baptist "Jack." -- H.L. Mencken