Forgot your password?

Comment: Re:Carry the one (Score 1) 157

by FatLittleMonkey (#47587503) Attached to: NASA Tests Microwave Space Drive

Unfortunately, even though you wouldn't have to supply propellant, you would still need to supply the energy to accelerate it.

Actually you don't. Any reactionless thruster can be turned into a free energy machine. If force-produced is directly proportional to energy-input (eg, the device in TFA gets 31uN/W) regardless of position in the universe and direction of thrust (**), then the change of velocity per unit time is also proportional to energy-input. Linear. But the kinetic energy available is proportional to the square of total velocity. There's a cross over velocity where the increase in kinetic energy is greater than the energy input necessary to produce that change in velocity. Stick a set of reactionless thrusters on a flywheel, hook the hub to a generator, spin it up until the tip-velocity passes the cross-over, and from then on it's a free energy machine. So the potato would have one set of EMdrives powering a generator, and another set for propulsion powered by the generator.

At 31 microNewtons/Watt, the required tip velocity is over 30km/s, a wee bit past material limits. But as the "Q" increases in the EMdrive (predicted for the use superconducting cavities) the cross over velocity drops below 100m/s, well within the tip-velocity of a generator flywheel.

(** An anti-gravity drive that could only act in the direction of existing gravity, and lost efficiency moving out of a gravity well or at speed within a gravity well, wouldn't be a free energy machine. And the inventors of the EMdrive have indeed created some ad-hoc explanation for why theirs loses power at speed (to which every critic screams back "relative to what!") and can thus magically only be used to hover.)

Comment: Carry the one (Score 4, Informative) 157

by FatLittleMonkey (#47581243) Attached to: NASA Tests Microwave Space Drive

No, the question is how fast can it accelerate the average potato. NASA reported 30-50 mN of thrust., call it 40. The average potato is about 375 grams, call is 400 even so math is real east. F=m*a or a = F / M or 1e-7 m/sec^2.

40 mN is 0.04N

400g is 0.4kg

a = F/m = 0.04 / 0.4 = 0.1 m/s^2 not 0.0000001 m/s^2.

Therefore accelerating for 3e7 seconds (one year) results in a velocity of 3000 km/s. About 1% of lightspeed. And a distance of 330AU. You'll hit one lightyear in 19 years. Two lightyears in about 28 years, if you turn your potato around to decelerate, you'll deliver your potato to Alpha Century in 56 years. If you want to cook your potato by skimming one of the stars, it'll only take 38 years.

Comment: Re:Astrobiology (Score 2) 39

by FatLittleMonkey (#47563401) Attached to: Enceladus's 101 Geysers Blast From Hidden Ocean

Alien DNA would definitely screw with my Christian belief system.


You guys survived Earth being round, the heavens not including Heaven, Earth not being the centre of the solar system, then not being the centre of the universe, humans not being the majority of Earth's history and the bible not covering most of human history, and of course not having a single major biblical event (pre-7th century BC) appear in the fossil or archaeological record.

Why would two separate creations of life suddenly throw you?

Comment: Re:Send a robot (Score 1, Informative) 84

When it's time for an asteroid mission, it will probably be robotic.

ARM is primarily a robotic sample-return mission. The intent is to send a robotic system to intercept and literally bag a small, 5-7m, NEO asteroid, then using ion drive bring it almost all the way back to Earth.

Only the actual sampling will be performed by humans, through slits in the bag with a pick'n'reach tool. Hence in order to create a destination for SLS/Orion that is within the system's incredibly limited capability, the asteroid will be returned to the highest orbit that the SLS/Orion system can reach (lunar orbit) in order to pretend the $30+ billion that will have been spent on SLS/Orion development by then has somehow all been worth it.

It's a bit like sending out a 19th century whaling crew to catch and tow an iceberg back to New York, so that an alternative retarded version of Adm Peary could stomp around on it, waving a toy ice axe, shouting, "I are exploring, derp!" while setting fire to piles of money to keep warm.

The robotic part is a useful mission, IMO. The human part is of course not only a waste, but a waste intended to justify a greater waste. Spending even part of the remaining $20 billion SLS/Orion development on a series of entirely robotic asteroid and comet sample return missions would vastly outweigh the returns from the single ARM human mission.


"is one step toward a proposed (mid-2020s) mission to actually visit a captured asteroid in lunar orbit. [...] their mission also includes a 10-minute communications delay, to simulate the high-latency communications with mission control that would be inevitable for an actual asteroid mission."

The moon is 1 1/3 light-seconds away. Hence a 2 2/3 second round-trip delay. Say 3 seconds with relaying. SLS/Orion isn't capable of reaching 5 light-minutes away from Earth. Derp.

Comment: Re:TCO (Score 5, Informative) 156

by FatLittleMonkey (#47546733) Attached to: Valencia Linux School Distro Saves 36 Million Euro

Good point, thesupraman forgot one additional MS TCO assumption:

"There's no ongoing transitional costs from Microsoft upgrades."

Microsoft only compares with a stable Win/Office environment. But often these transitions to Linux/FOSS are made in the face of a major Windows/Office upgrade. So the comparison is "Transition to FOSS vs Transition to different MS-ware".

Comment: Re:SLS and comparing to spacex (Score 2) 132

by FatLittleMonkey (#47536197) Attached to: SLS Project Coming Up $400 Million Short

Yes, the SSL will start at 70t and move forward to (maybe) 155t.

The 70 ton version won't be finished until at least 2021, work won't start on the >130t version until after 2032. The "Block 0" version might fly by 2017 (if, the GAO reports, they receive more funding.)

Falcon Heavy likewise is supposed to fly by 2015. So allowing for the usual SpaceX delays, probably around 2017/2018, same as SLS-Block-0.

The difference is, Falcon Heavy will cost the tax payers almost nothing to develop and less than $100m per launch.

The SLS will cost around $3b/yr to develop, and at least $500m per launch (ignoring most costs. This was the same kind of number they used for the Shuttle, but which actually cost $1.5b per launch.)

53 tonnes for $100m. Versus 65 tons (about 58 tonnes) for $500m + $12b dev. Or 70 tons (about 63 tonnes) for $500m + $20b dev.

So you could launch 5 FH's for the official "launch cost" of SLS-Block-I. So over 250 tonnes versus about 63 tonnes. And you'd save $20 billion in development costs that could instead be spent on mission hardware instead of launch hardware.

Some things are better built and have less wastage in large intergated units on the ground than assempbled in space.

Define "wastage". If you are spending $3b/yr just to develop the launcher, how much do you have left to develop the mission hardware?

If your launch costs are a tiny fraction of SLS, you can launch more hardware, more often. Which means you can do a lot of testing on orbit. Which lets you incrementally develop your hardware (instead of the current method of one-off, must-not-fail process.) Build a little, test a little. Let your engineers learn their craft before you design the final version. (I wonder how much would have been saved on JWST, had they built multiple versions, starting simple with each adding a single novel capacity. Instead of trying to throw everything into the first and only, must-not-fail version.)

With SLS, you can't afford to build anything to actually launch. With SpaceX, you get to ignore launch costs and just develop mission hardware. And once you get into that frame of mind, you use the same low-cost development model for everything, saving even more money.

Comment: Re:Speaking of the future... (Score 1) 108

by FatLittleMonkey (#47504151) Attached to: A Look At NASA's Orion Project

How about lobbying for increased funding to NASA for the things it needs,

Two reasons. 1) NASA's funding has been relatively constant, as a percentage of the Federal budget, for 30 years. Lobbying for more funding has resulted in precisely zero effect.

2) It would be worthless giving NASA more funding if it is incapable of managing the funding it already receives, additional funding would be entirely absorbed by the flagship programs, such as SLS/Orion, or on the science side JWST. NASA could already increase the amount of mission it buys with its existing budget by spending it better. And that agency would actually deserve more funding.

And for the record, I wasn't calling for more funding for COTS/CC. (Especially since COTS is finished development and is operational.) But for more programs to be designed like COTS. Multi-vendor, fixed-funding fixed-goal, payment-on-delivery programs. Eliminating the cost-plus model. Eliminating the single massive program that everyone throws their pet dev project into.

For example: There are calls to replace the Russian-made RD-180 engine on Atlas V. This will inevitably end up being an eight year, sole-source, multi-billion dollar, FAR (cost plus) contract for ULA (subcontracting to Aerojet, subcontracting to...) to develop a local version of the RD-180. Every spec will be spelled out in excruciating detail, even though the USAF will invariably approve variations due to the resulting engine under-performing. Probably late and over-budget. All to replicate a surplus 1960's Russian engine that operates in a way US engines traditionally don't.

If, otoh, the same funding was used in a COTS-style multi-vendor program, you would end up with 3 or more brand new engine families, delivering a hell of a lot faster than 8 years, with multiple redundancy for vendor failure. This would not only solve the actual problem (being dependent on Russian engines), it would stimulate a whole new generation of low-cost rocket development, and a whole new generation of engine-development engineers. That knowledge-base could then be set a new task of building the next generation of (say, larger) rocket engines.

Comment: Re:Do you have any hands-on experience ? (Score 1) 667

by FatLittleMonkey (#47503951) Attached to: Russian Government Edits Wikipedia On Flight MH17

I only ask because Singapore Airlines said right after the shootdown that:
"Customers may wish to note that Singapore Airlines flights are not using Ukraine airspace."

Flightradar24. Singapore Air Flight SQ351, 2014-07-17.

SA lied and are being shredded in social media for that comment. Finnair did exactly the same thing. Both have done the "if anyone was offended" non-apology and claimed they were referring to future flights.

Comment: Re:Do you have any hands-on experience ? (Score 3, Insightful) 667

by FatLittleMonkey (#47498683) Attached to: Russian Government Edits Wikipedia On Flight MH17

No. I'm pointing how how empty it is today, compared to the airspace around it. Obviously keeping such a big chunk of airspace empty is something that the whole airline industry would want to avoid like the plague.

If Nyder had his way, all of Ukraine, plus Russian and European airspace near Ukraine, plus Iran, Iraq, Syria , Israel, Egypt, Libya, Afghanistan, northern Pakistan, the Pakistan/Indian border, Kashmir, the Strait of Hormuz, Sea of Japan, South China Sea, etc etc, would all be kept clear of civilian air traffic at all times.

And then he'd complain about the density of air traffic in the remaining few routes, and the inherent safety risk.

10 to the 12th power microphones = 1 Megaphone