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Posted by Jack Crossfire | May 12, 2018 @ 05:44 PM | 1,052 Views
NASA Mars Helicopter Technology Demonstration (1 min 23 sec)


The speech:

https://www.nasa.gov/press-release/m...-rover-mission

More details on kiwipedia:

https://en.wikipedia.org/wiki/NASA_M...licopter_Scout

After decades of rumors about such a thing, which no-one took seriously, it was finally included on the next Mars rover. The finer details had a few shockers.  It uses solar charged lithium batteries, coaxial blades, has no blade shroud, & no obvious way to right itself.  It weighs 4 pounds & looks quite top heavy.  It's basically the exact opposite of a copter you'd expect to be sent to Mars.


The equivalent atmospheric density on Mars is 100,000ft on Earth or 3x higher than the highest a copter has ever flown on Earth.  A quad copter would not be efficient enough to do the job.  It's inevitably going to crash & roll over, so apparently this simple use of long legs is able to recover without human intervention.  Maybe the blades can kick it upright long enough to get going or it can tumble down a hillside until it reaches a flat spot.  There are still many ways it can get stuck, so it needs a major investment in autonomous programming which can avoid getting stuck.






The dark, blurry footage from JPL shows the solar panel on top of the blades blocking airflow, no obvious use of a flybar, & lots of vicon balls for tracking position.  You'd think a solar panel below the blades would allow more lift & get dusted off by the airflow.


A copter that could travel great distances on solar power & recover from crashes is what we all wanted, 40 years ago.  The solution seems so simple, it makes you wonder why China didn't already give hobbyists such a thing.  
Posted by Jack Crossfire | May 10, 2018 @ 10:28 PM | 1,396 Views
Mane engines stepped up to 190,000lbs thrust with higher ISP.
Merlin vac increased to 220,000lbs.
The merlin vac is still throttled down to 210,000lbs to study vibration.
The octaweb is stronger aluminum 7000 instead of aluminum 2000.
The rocket base is now titanium with water cooling.
The black sections are a proprietary material, probably derived from shuttle tiles, but without the porous sections which absorbed water.
The avionics & IMU were redone.
Current 2nd stage recovery efforts are only to determine the mass impact of recovering it without impacting BFR development.
Falcon 9 launches would cost under $6 million if they could reuse the 2nd stage.
He wants to launch the same booster twice in 24 hours, in a demo mission next year.
The new COPVs are the most advanced & tested ever made.
Posted by Jack Crossfire | May 10, 2018 @ 02:36 AM | 1,893 Views
Got a somewhat acceptable wing by creating 4 profile sketches, then lofting them. Freecad can't create a solid from a surface, so you have to create 2D slices for the lofting operation, with matching curve & line segments. Freecad did manage to interpolate the sketches into a smooth curve. Suspect this process would be much easier to tweek & give smoother results if it was built up from equations rather than paw sketching, but the reference design is going to change. The automated version would have to use a constant number of line segments for each profile sketch instead of curves.




The only way to create windows was writing the basic equations in a python script. There are no basic cutting, pasting, copying functions in the sketcher. The lion kingdom wanted see through windows instead of textures.

The script created a window creation tool. Then the tool cut out windows you can see through. OpenCAD has a few rounding errors, causing some windows not to open. Offsetting by 1mm in random places seemed to work. There's the issue of a tinted, reflective texture. The whole model may end up being from equations. Tweeking is a buster because it takes a long time to recompute the model.




The parts -> thickness tool doesn't work at all with booleans or constantly locks up. The only way to make hollow solids is sketching a cross section & revolving/lofting with solid mode enabled.
Posted by Jack Crossfire | May 09, 2018 @ 02:01 PM | 2,219 Views
Long thought to be unfixable, the camber is determined by a bend in the wishbones. It turns out the wishbones can be flipped over, giving a closer to ideal camber position. Further refinement is within the limits of changing the suspension height. The result was much closer to ideal, but increased the rolling resistance, put more stress on the steering servo, & decreased the range. The steering horn jumped cogs much more often.


There are servo savers & a return to sloppy steering or going back to stock camber & tire wear. Steering with the direct servo link was so solid in this spherecam video, it didn't need any stabilization.

3DRRrrrrrun (3 min 18 sec)

Posted by Jack Crossfire | Apr 26, 2018 @ 10:34 PM | 2,179 Views
Shapelock was long theorized to be an effective adhesive on plastic, but never used it in 7 years. Decided to finally apply it to the front wheels & made a test blob.


For this application, it was easier to use hot air than boil it & reheat it with hot air after applying it. It melted the plastic slightly. No amount of hammering could kick the test blob off. After a 10 mile drive with 5 at higher speed, it was declared a success.


The repaired shaft was misaligned, there's absolutely no way to release the shapelock & we know the consequences of misaligned wheels, so they still have to be replaced. Creating shapelock fillets around the bearing is another necessary step in fabrication.
Posted by Jack Crossfire | Apr 26, 2018 @ 12:40 AM | 1,800 Views
4 months after the last wheel failure, the same left front wheel broke off again.

https://www.rcgroups.com/forums/show...e#post38834656

& the right front tire continued to have wear problems. At least it got a good video before it died.

19 minutes at 7m18s per mile (2 min 40 sec)

Posted by Jack Crossfire | Apr 25, 2018 @ 01:16 AM | 1,329 Views
If the price is based on 100 passengers, with only 40 staterooms, they're planning on people traveling in family units with some of those families having kids young enough to sleep in the same room. The actual price per room is $500,000.

This is might have been Elon's parent's organisation, but it's definitely not the mane social organisation today. Lions still insist the mane customer will be confirmed bachelors looking for the ultimate retirement home.

Most families today from baby boomers to generation X to millenials still have a single male breadwinner earning most of the money & a "partner" earning pinch money.

What's advertised as $200,000 per person is really $500,000 a man has to produce for a room, whether traveling alone or with 2 family members. There might be a way to split it with a room mate, but that still hits $250,000. Suspect that's the mane way most of us will go, but since we wouldn't have to sleep at the same time, there wouldn't a real need for each person to have an entire room.
Posted by Jack Crossfire | Apr 22, 2018 @ 12:13 AM | 1,758 Views
https://www.instagram.com/p/BRwgf8bgGWV/


Our 1st & only view of the inside of the interstage. It probably would have cost a few thou from the BFR budget to put a roof on it or strip out all the guts, so Musk said forget it. They did strip out the pushrod that ejects the 2nd stage & hastily strung an extension cord to a warning light. The extension cord had a little left over. 2 wires in mid air appear to be additions. They could be a radio antenna used by someone else. What are the chances of retired Falcon 9's being sold as cell phone towers?

You can see everything mounted directly on the convex top of the LOX tank. Not content with plain old rods, they used horn shaped rods. It must be the most weight optimized way to transfer torque from a narrow diameter to a wide diameter.

There's a triangular enclosure which could only be a triple redundant brain box, where the 3 computers are mounted symmetrically. All the software flying the 1st stage & the IMU are probably in that box, all calibrated for its orientation on the LOX tank. We also see what could only be the nitrogen thruster tank & the pesky hydraulic fluid tank. Surprising such a small tank is all the nitrogen it takes to fly it back. There's no effort to balance it by mounting the tanks symmetrically.

The torque rods are already looking a bit rusted. The guy obviously doesn't know a 4k copy of the video is stored on the quad copter, but barely knows enough to hit send on an instagram app to upload low res telemetry.
Posted by Jack Crossfire | Apr 18, 2018 @ 04:41 PM | 1,566 Views
10mph in modified flip flops (3 min 37 sec)



Was quite pleased by how stable it was at 10.9mph. For most of its life, it couldn't go straight at 10mph, even when completely empty. It now goes straight even with a camera pole on it. Better living through FIR filters.
Posted by Jack Crossfire | Apr 15, 2018 @ 09:25 PM | 1,847 Views
Still fielding software ideas, came up with this: the Big Falcon Simulator, a very high fidelity simulation of a very large rocket, with the highest quality models & sounds possible. It would accurately simulate flights or have a racing mode with knockdowns. Previous simulators have horrible graphics. They especially need realistic flames.
Posted by Jack Crossfire | Apr 15, 2018 @ 03:30 AM | 1,781 Views
City running in 360 (2 min 28 sec)

Posted by Jack Crossfire | Apr 11, 2018 @ 10:12 PM | 1,355 Views
You always had a hard time finding your place in this world, haven't you. Never knowing your true worth. You couldn't settle for less than an ordinary life. You feel like you were meant for something better. Something special.
Posted by Jack Crossfire | Apr 09, 2018 @ 01:42 PM | 1,917 Views
Mind blown beyond the capacity for rational thought by today's Elon photo, the BFS oxygen tank mold, now sitting at 801 S. Reeves Avenue in Long Beach. We now know the current state of progress in building it, the tanks won't be made in Seattle as previously thought, & they can't begin making the tanks until the factory in Long Beach is up. It's going to be very much a space going ship built in the traditional birthplace of ocean going ships: a harbor. Mass transit in space begins as mass transit around Earth began, by sea.


Watching SpaceX move ahead with the giant rocket in a tent, as the permanent factory remanes bogged down in years of paperwork, is quite a contrast to Bezos's traditional approach of spending 3 years building a proper factory before starting a single mold.
Posted by Jack Crossfire | Apr 04, 2018 @ 01:59 PM | 1,796 Views
With US still over 1 year away from being able to launch humans into space again, what a story it would be if someone stowed away in a cargo mission. It would be like a Doolittle raid, but a raid against bureaucracy & management. It would be riskier than Alan Shepard's 1st flight, because the cargo modules have no launch abort capability. Beyond that, it would be the same as that 1st flight, despite all the concern about minutiae in the flight termination system, life support system, & micro meteoroids. Indeed, much of the last 8 years of pain has been micro meteoroid shielding standards.

The stowaway would be a man, of course. He would have a food supply & a bathroom hidden somewhere. Once on the space station, they would have the issue of feeding him, not having enough room in the Soyuzes to evacuate the station, the life support system encountering loads not seen in 8 years.

The real drama would be the consequences of stowing away. Would he be shot for treason? Would NASA give up on human spaceflight entirely because they couldn't enforce enough meaningless regulations? Would private space programs tolerate more risk?
Posted by Jack Crossfire | Mar 25, 2018 @ 05:17 PM | 1,972 Views


There has never been a fad held in as much secrecy as the self driving car craze. It's been 15 years of startups, yet no source code or algorithm has ever been released by anyone working on a full sized self driving car, while past generations were quick to release source code for quad copters, web browsers, operating systems, & video codecs. Every Stanford student is working on some self driving car project, but with no place to start. It's like thousands of Linuxes being written from scratch, with no-one making any progress beyond what can be done in the 5 years between graduation & a better living through flipping houses.


Tried enhancing the only released footage of the Uber crash, the 1st fatality caused by a self driving car, but it was a downscaled, compressed copy of a video. The dynamic range was too poor to resolve any details in the shadow, where a human would have seen details.  The current generation has an attitude that the car did everything possible & blindly accepts the company claim that the secret autopilot was extremely sophisticated.  To someone programming autopilots for years, it didn't seem like a very capable autopilot at all.



The car was going too fast to stop in the visible distance, which for the car could have included the LIDAR range. Human drivers are told to go no faster than they can stop in the visible distance.  Someone with no ivy league degree would have at least used a better camera in a self driving...Continue Reading
Posted by Jack Crossfire | Mar 13, 2018 @ 02:13 AM | 1,997 Views
FULL Elon Musk’s session at SXSW 2018 on latest news | March 11, 2018 (1 hr 9 min 42 sec)


Watermarking, elevator music included.

Hard to believe he still sticks to direct democracy, after Calif*'s experience with it. Half the state is in poverty & the infrastructure voted in by direct democracy is the same thing he's trying to undo.


If he's still sticking to the claim of building the 1st BFS, it's most definitely in pieces on the mane factory floor. They'll send it in pieces down the 110 to a boat & complete it in Texas. They already moved a much larger tank to Seattle.


The biggest existential threat is not artificial intelligence or a world war, but economic collapse. Modern dogma since 2014 has said debt never has to be repaid, but we can endlessly innovate our way out of it. Some say it will have to be repaid, leading to a new dark ages. Modern dogma feels exactly like 1999, when they said the internet was so valuable, it made all previous debts meaningless & was like starting a new economy from scratch.
Posted by Jack Crossfire | Mar 06, 2018 @ 10:24 PM | 1,620 Views
Listening to Ready Player One, the lion kingdom is reminded of Lawnmower Man & Cloak & Dagger. The problem with books about the best computer game ever made is for the book to be convincing, the author has to really invent the best computer game ever made, which no author ever does.

The Oasis sounds incredibly boring. The author devotes too many pages to the rules & gameplay of something so boring, when it should just be an accessory to the plot.

Otherwise, the technology has existed to make the Oasis & certainly Lawnmower Man, for 20 years. Why hasn't it actually materialized? It would be trivial to make a chatroom using $5 VR goggles like what the book described, but lions suspect such a program would be incredibly boring.


The other thing was, driving the robot for 10 miles while listening to the book is like being in the book. The sky gets darker & the LEDs get brighter as the cars full of ordinary mortals line up on their commutes. You bang away on the only game controller of its kind in the world, throwing down mile after mile on the only robot of its kind in the world. The lion kingdom wondered if the mane character ever had to pause the game because his running robot only had 10 miles of battery power.
Posted by Jack Crossfire | Feb 20, 2018 @ 03:58 PM | 2,374 Views
Hands-On with Skydio R1 Autonomous Drone! (22 min 3 sec)







Really impressive demos from Skydio in Redwood City. Quad copter startups have been hit or miss & it looks like the same pile of plastic scrap that every startup besides Apple produces, but what they showed here was exactly what I wanted to do for years, with ground vehicles. It looks like it could really navigate most of the mobs I have had to navigate manually. They showed it briefly flying in front of the athlete, despite not having prior information about where the athlete was going. The flight time is undoubtedly very short & the $2500 is almost 1 month of rent.  As a $2500 consumer quad copter, it has no chance, but it would have a chance as a kit allowing developers to add autonomy to ground vehicles.


They're the 1st to consolidate a lot of the bits of research that were done in the vicon rooms for the last 10 years, into a complete product. They emphasized the demo of the fixed wing flying in a parking garage.  It's the 1st time anyone has shown the NVidia TX1 doing anything besides raising its stock price.


Not sure how well it would translate to a ground vehicle, because a ground vehicle needs to stay on a certain path. Prior knowledge of roughly where the athlete was going & where the path was might allow it to do the job. Suspect GPS has not improved enough to stay on a path without some other input.


It wouldn't translate well to a Casey Neistat application. His interest is...Continue Reading
Posted by Jack Crossfire | Feb 20, 2018 @ 03:08 AM | 2,646 Views
Obsolescence has been a big problem for reusability. They haven't been able to recover any more Falcon 9's lately, because of the plan to switch to block 5. If a product evolves too fast, there's no need to ever reuse it. They'll retire the 1st reusable Falcon 9 after only 26 launch attempts.


In 4 more years, they want to have the BFR doing all the satellite launches, but after Falcon Heavy launched, Elon sounded eager to continue improving the old Falcon 9. So maybe in another year, it'll be a Falcon 9 with longer 2nd stage that replaces block 5 & makes recovering block 5 worthless because of obsolescence.