Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

×

Comment: Re:What if... (Score 1) 66

by DanielRavenNest (#49361225) Attached to: US Air Force Overstepped In SpaceX Certification

SpaceX couldn't get an export license then. Rockets fall under the "International Traffic in Arms Regulations" (ITAR) and need a license to export. We even had to follow those rules for the Space Station modules being built by Boeing. That's despite it being an international station occupied by lots of foreigners, Russians even.

Comment: Re:I'd put a 'may' there (Score 1) 39

by DanielRavenNest (#49361151) Attached to: Taxpayer Subsidies To ULA To End

> It does seem that the ULA has been mostly sitting on their laurels sucking at the government teat for a long while now.

Let me explain how this works. At the start of the Sea Launch program, which Boeing was a partner of, and I was working on, our program manager was an ex-Air Force officer who was a launch director from Vandenberg (where the Air Force launches polar satellites). He was a smart and competent guy, but the main reason Boeing hired him is *he knew all the right players on the Air Force side*. Another manager of mine was a former Marines officer who had done helicopter procurement.

When the people who make the buying decisions already know you, because they used to work with you, you have a much better chance than someone they never met before and have no idea how good they are, if they will get along, etc. This "revolving door" works in the other direction too, where someone in industry then goes to work in government, in the same field. The problem is you often can't find anyone else who is qualified to oversee such contracts.

Comment: Re:And now why this can not be done in the USofA (Score 1) 316

> And no effective way to store it for use at night and the evenings.

I guess you haven't heard of solar thermal with storage. You concentrate sunlight with curved troughs or steerable mirrors. This is used to heat a storage material such as thermal oil or rocks. In the off-hours you use the heat to boil water, and the steam runs through a tubine-generator set like in conventional fossil plants. There haven't been a lot of thermal storage units built yet *because we don't need them yet*. For example, the 400 MW Ivanpah solar thermal plant is on the same power line as Hoover Dam. The dam serves as storage by not using water when Ivanpah is running, and saving it for night-time. Eventually you run out of existing storage capacity, and need to add more, but we are not there yet in most places.

Comment: Re:Viking vs Curiosity (Score 3, Interesting) 89

Several reasons:

* Curiosity has almost twice the landed weight of the Viking Landers
* Rocket thrusters firing at ground level would contaminate the soil, which they wanted to analyze
* Curiosity is a rover. You either are carrying dead weight from the propulsion system, or need a roll-off ramp
* Curiosity's wheels and suspension allowed landing on rougher ground by landing on them directly. Rocket thrusters might have damaged the wheels by throwing rocks around

Comment: Re:delay (Score 3, Interesting) 89

Elon Musk wants to build a Mars Colony too, but he has a rocket factory (SpaceX), and several other businesses that can earn lots of money *and* supply hardware for Mars: Tesla (electric cars on Earth, electric rovers on Mars), Solar City (home roofs, and soon high efficiency cells for Earth and Mars), and the Gigafactory (batteries for vehicles *and* nighttime backup for solar panels). So his plan is a lot more feasbile than Mars One's.

The real question is where is Mars One going to get the $6 billion they estimate for their project? If they have that money, they can hire the right aerospace companies and engineers to build real hardware. But without it, they just have pretty pictures on a website, and aren't going anywhere.

And as someone who helped build the Space Station, and written a book on Space Systems Engineering ( http://en.wikibooks.org/wiki/S... ), Mars One isn't being innovative *enough* to really bring down costs.

Comment: Re:obvious issue (Score 1) 59

by DanielRavenNest (#49309837) Attached to: Report: NASA May Miss SLS Launch Deadline

Sounds like someone failed to do a proper "systems engineering" job in the first place. Part of that job is identifying system interfaces between the parts early, then controlling the interface. In computer terms, the PCI specification is the interface between the PCI slot and the PCI card that goes in the slot. You have to control that specification so the parts will work together. A rocket and the launch site it uses are just bigger and more complicated interfaces.

Comment: Re:boxen and Borg? (Score 3, Interesting) 296

by DanielRavenNest (#49294473) Attached to: To Avoid NSA Interception, Cisco Will Ship To Decoy Addresses

Then the answer is not to send the hardware to empty buildings, but to install a GPS tracking device in the shipping container, and see where it goes off-course. Bonus points if you can track it all the way to the NSA modification warehouse, but at least if you know where it got diverted, you can figure out *how* it gets diverted. I suspect the truck drivers are in on it, but without tracking data, that is just a theory.

Comment: Re:Mars Society (Score 4, Insightful) 169

The head of the Mars Society is Robert Zubrin, who is a well qualified and inventive aerospace engineer. I assume the rest of their work at least involves doing the relevant math.

The Mars One project's problem isn't wanting to go to Mars, it's the missing step two in their plan:

(1) Raise around a million dollars from crowdsourcing, tee shirt sales, and application fees
(2) ???
(3) Finish $6 billion worth of space hardware and launch it.

Elon Musk/SpaceX also want to go to Mars, but they have actual rockets and customers, and his other businesses (Tesla and Solar City) both stand to make a lot of money, and are useful to the original goal. You will need electric rovers, batteries for power storage, and solar panels on Mars. It helps if you have companies that already make that stuff. So I rate the SpaceX Mars program way higher on the probability scale.

Comment: Re:Wind is (Score 1) 262

by DanielRavenNest (#49252919) Attached to: US Wind Power Is Expected To Double In the Next 5 Years

> Could you not place solar panels underneath the windmills?

In theory yes. In practice the wind resource is highest in the Midwest, and certain mountain passes. Midwest combines wind and field crops, because the wind turbine only needs about 1% of the land area to install the tower and the access road. The turbine as a whole doesn't create too much shade, so crops grow just fine around it. Mountain passes have too much geography in the way, and are not ideal for collecting sunlight.

Solar is getting installed preferentially in dry areas of the Southwest, because you get more sunlight hours per year there, and on industrial/commercial and home rooftops, because it's easier to compete with retail electric rates. The big desert solar farms have to compete with wholesale utility plants. It's popping up in other places too, I saw some panels in a field in NW Georgia, but the ones I mention above account for most of the installations at present.

Comment: Terraforming is Premature (Score 2) 228

There is no need to terraform the bulk of Mars until you have enough people there to justify it. Until then it makes much more sense to restrict the terraforming to the space underneath your habitat domes and arches.

Ideas that Mr. Robinson may not have been aware of also make colonizing easier. One is "Seed Factories" - self upgrading automation that grows from a starter kit, the way a tree grows from an acorn. The starter kit includes plans for the sequential addition of new machines, until you have a fully grown industrial capacity. Another is an improved space elevator system. The static ground-to-synchronous orbit elevator is not the lowest mass design by a long shot, and improved designs can be built with today's materials, rather than requiring "unobtainium".

Comment: Re:Politicians will be stupid but scientists/techn (Score 1) 356

by DanielRavenNest (#49246401) Attached to: New Solar Capacity Beats Coal and Wind, Again

> Of course I could be nitpicking and point out that the sun actually is a huge nuclear reactor.

We live near an unshielded gravitational confinement fusion reactor, that floods the entire Solar System with several kinds of lethal radiation. We only survive here on Earth because we have a strong magnetic field *and* a thick atmosphere to protect us. Even so, the Sun causes over 100,000 cases of malignant skin cancer every year, and lots of other causes of death. It would never have passed safety review if we treated it like we do new power sources.

Comment: Re:Considerable resources? (Score 2) 214

by DanielRavenNest (#49237705) Attached to: Billionaire Teams Up With NASA To Mine the Moon

> And lunar He-3 mining is pretty useless.

There's another reason besides the ones you mention. Parts of the Moon have Thorium concentrations of 15 parts/million. That's about 1000 times higher than the He-3 concentration, and the energy output from fission isn't that much lower than fusion. Not to mention we know how to build Thorium reactors. So for a given amount of mining work, you would get more energy mining Thorium on the Moon. Now, considering that Thorium isn't terribly scarce on Earth, you can figure out that Lunar mining for Earth use isn't very sensible. And if you need power on the Moon, solar works much more easily. Nighttime power can be handled with solar-thermal. Vacuum makes a great insulator. Heat up a bunch of rocks with concentrated sunlight, then use that heat to run a generator at night. You will never run out of rocks on the Moon's surface, nor sunlight for that matter.

Hackers are just a migratory lifeform with a tropism for computers.

Working...