Green Baron

Sure it does. I simply wasn't thinking of an aerodramatic plane with a rocket motor. Nice :-)

True, but not in a parking lot with public traffic. If you know someone who owns a farm one could practice there. Or automobile clubs can have practicing circuits where people can train, even with a (paid) instructor. - ninja'd - In some countries there are small licenses to drive cars with limited power and max. speed. OP must actually go to a doctor and driving school to get an answer to his questions. Which is as easy as going to a doctor and driving school and ask a simple question :-) Doctor: can i despite my deficiencies ? Driving school: would you ? Here's money ! https://www.youtube.com/watch?v=LJOz9BNwV4Y

Maybe an RC rocket could be used as a platform .... Cancel this, i don't know if such a thing even exists.

First, the search function here and it the web will give you some answers. tl,dr: while other bases than carbon (e.g. sulphur, silicon) are imaginable (though by for not as effective as carbon), a replacement for water is improbable. Of course, much can be fantasized if you stretch the definition of life. This describes possible pre-life conditions: https://www.nature.com/articles/s41598-017-18483-8 Not in a way that is possible with highly reactive materials that are used on earth and are hypothesized for being the base elsewhere as well, because they are abundant and "easy to use". It is for a cause that people search for possible liquid water. Is it possible to port a genome between species on earth ? ;-) It is too early to ask that question because nothing is known about life in different expressions. No. We can't "make" normal human beings (yet) except through the natural processes :-) If you say so :-)

I try :-) If you are in front of a programming project you must first identify your problem. Then you break it down into components that you can each handle separately. You haven't yet done so, not even given the components of your problem. "Is there a drag and drop python program to control a rocket" does not address the problem. First, Python is not the right tool for the job, second, if the toy rocket manufacturer doesn't offer such a thing then this is for a reason (all the hard- and software would make it too expensive and a radio relay needs certification). I give you an example out of my fantasy, i do not claim that this is real: Wish: I want to control a rocket ascent. I have a rocket that has a fixed motor that can be started and then burns with a thrust for a time. In that time the rocket mass goes from a to b and the acceleration from x to y. I neglect any atmosphere. For that, to get a number for the actual climb rate and acceleration the rocket needs a timer that starts at motor start. From the timer, with the initial information, current mass and acceleration can be calculated. Furthermore, it needs something to tell it in what direction it is facing (GPS can't do that, there is no time in the short flight, a gyro would), actuators and position sensors for the fins and some modeling of how the fins affect the course. A microprocessor program must integrate the values. It needs readings from gyro, sensors, control of the actuators and an internal model of the flight to fell the right decisions. Tools: Since the flight is short (seconds) it must be fast, like 100s of loops per second of read out, crunching and sending to the actuators as well as feedback with the gyro. And it must be lean since we can't take a full operating system on every flight when half of them are doomed to end up in a pond or on the rocks. Which brings us to C and Assembler, the typical tools for microcontroller programming. Which brings me back to the initial question: it can't be answered that easily, if you want to get into coding start with C. It is free, straightforward, doesn't overwhelm you with data structures, i/o and libraries (in the beginning) and you are sure to do things right from start or they won't work. :-)

Well, the article cites NASA saying that SpaceX used a part without testing and outside of manufacturers specifications. “the implementation was done without adequate screening or testing of the industrial grade part, without regard to the manufacturer’s recommendations for a 4:1 factor of safety when using their industrial grade part in an application, and without proper modeling or adequate load testing of the part under predicted flight conditions. This design error is directly related to the Falcon 9 CRS-7 launch failure as a ‘credible’ cause.” "In simpler terms, the steel strut that SpaceX chose was not certified to be used in such conditions. Furthermore, SpaceX did not meet the 4:1 redundancy requirement that the manufacturer had instructed." So, it was not a manufacturing defect but bad engineering. The strut actually held what it was designed for. The article also says that SpaceX corrected that immediately after being informed by NASA. I can imagine that a certification would have been revocet immediately had they not done so. SpaceX informed the public differently, by stating or implying that the they changed the manufacturer because of bad material, which is not the case. Furthermore: "That being said, in January of this year the Falcon 9 Full Thrust received certification to launch Category 2 NASA missions. Category 2 certification allows Falcon 9 to fly medium value NASA payloads. Such certification would not have been warranted if NASA did not have significant confidence in the Falcon 9 launch vehicle." iow: SpaceX had to change it because their rocket would not have been certified. Anyone remember SpaceX suspicion that somebody could have shot at their rocket when it popped on the pad ? Haha ... :-) In the end it is not that bad to always have an independent investigation on complex failures. It might help to find out about the real causes and avoid them next time.

A brilliant mind and great scientist.

Yes, these are the brown and/or red dwarves and the minimum size to start an own fusion is ~13 Jupiter masses for deuterium fusion. If this is a full featured star can be discussed. http://iopscience.iop.org/article/10.1088/0004-6256/147/5/94/meta ~0.075 * mass of sun is needed for self sustained hydrogen fusion in a star's core. Example: http://www.eso.org/public/news/eso0503/ and https://sites.uni.edu/morgans/astro/course/Notes/section2/fusion.html

No, i mean knowingly using inappropriate materials because its cheaper. This is simply carelessness or maybe worse. If you mean Quantas 32 with the Airbus A380 thing, fatigue cracking is very difficult to predict and find out and maintenance errors can (but should of course not) happen. It is a totally different thing if things happen in course of a complex flow or are made wilfully.

There are hundreds if not thousands of different alloys for combinations of temperature, pressure, brittleness, flexibility and all have their specified uses, in case of critical applications like in refineries or power plants certifications on site are made to prove that the material withstands the predicted conditions. Material science invents new alloys with stated specifications if necessary and checks the suitability in lab or under real circumstances. Protocols come with a part if regulations say so, like for instance a valve in the cooling circuit of a power plant or a reactor inlet or connector. Even screws and nuts have to fulfill requirements if used in critical applications. Good SpaceX doesn't make airliners, they'd be in big steaming trouble had a plane crashed because of such a failure. And good that NASA hit them on the fingers to use the right stuff if they want a certification. We aren't yet so far that high performance rockets are made from diy stuff :-)

I/O error ? I recon its not the cable ? Outch ... Edit: login as root and unmount the partitions and execute an fsck that fits your filesystem. E.g. e2fsck, .... Assuming you have the system files on an own partition.

Glad the screen shot workaround works. Hopefully Ubuntu or the Gnomies come up with a fix soon(tm). WD Black have a nice reputation. 8-10% sounds ridiculously high. Since you're on Linux, a software raid 1 (two identical disks mirrored) costs some installation effort and another disk. Have a look at mdadm if you're interested ... Yeah, changing magnetic media after 5 years (or when the first errors are being reported) is a good idea imo. Edit: if you do it once in a session anyway then why not put the two lines in your login script, which should be /home/$USER/.profile ? But pls. check this, some distributions change the filenames. And don't forget to write a short documentation so that you don't forget to remove it when you update to a new version ;-)

No problem :-) If you get error messages it would be nice to have those. System logs in /var/log, e.g. daemon.log, messages, syslog, kern.log sometimes can contain info as well. Just saying. It is always good to have as much info as possible ...

I forgot "sudo ..."

*sigh* and that means ? We are trying to help but you don't make it easy for us. I don't use the keyring, but browsing the manpage i'd say restarting the daemon with "gnome-keyring-daemon --start --daemonize" (or -s -d) should work. Do you get an error message ?

Really ? Doesn't your script restart the deamon ?

Guys, before OP has all the features s/he uses up and running on a different DE the problem will long be solved, i think. @NewtSoup, then the solution workaround is easy: write a short shellscript that kills keyring-deamon and calls the screenshot and call that from your bar/desktop/whatever instead of the program itself. I have seen such a solution when i searched your problem, but don't remember the link now. If you can't find it i/we will be glad to help, it's no witchcraft :-) Hope that helps ....

Debian/Xfce4 user here, i last had contact with Gnome pre 2: Could it be a bug ? http://ubuntuhandbook.org/index.php/2017/07/fix-terminal-shortcut-printscreen-key-delay-in-ubuntu-16-04/ Can you start screenshot from a terminal without the annoying delay ?

Uhhh, not sure if the first part is correct. There seems to be a dispute about that. But i am no physicist ! I expect a wall of text here soon describing ... what exactly ? But OP describes a closed system, so there is little chance for energy to escape :-) Hehe. That's why i want to get rid of the suspicious mechanical stuff asap and go sailing. I have much more control over the sails than an engine ! Turnsweatheredfacetowardssunandwaitsforwindtoblowbaldhead

While i in principle support that, a forum like this (a game forum) must also leave room for free discussions between different views. It is a game forum, not a pre print server :-) As a game "Build a reactionless drive" one probably would have less of a chance to convince OP that his idea is faulty ... Just a few cents more from my side :-)

This goes into philosophy, but i find it important. One cannot make someone understand if he/she does not want to. This is actually a basic insight. As @YNM points out, OP actively rejects basic working principles of nature with the power of belief and this is too strong an "argument" to overcome. It needs a lot of time and education to make someone see that that what science has brought forth in the past 600 years (and before) is actually a quite encompassing collection of models that do work, which is proved every day in the application from theoretic sciences to such things as making cars or buildings, converting energy for use @home or describing processes in nature like climate, weather, plate tectonics, solar systems, clusters, galaxies, ... it works ! Not always perfectly and some in a manner that needs refinement or even redefinition, there is a scientific process to ensure that the development goes in a reasonable way. @Lordmaddog: even if you believe that much of science is wrong, you first must understand how it works before you criticise it. Generalisations and diffuse doubts don't get us nowhere ...

Oh, there are more meanwhile. Mercedes B, VW Golf, Renault Zoe, Kangoo and a small 2 seater, Smart 2-seater, Opel Ampera, .... they still have a more limited range compared to American models but all announced a new palette for the coming 2-3 years. They must to fulfill the fleet CO2 emissions because nobody is buying diesels any more. How comes ? *devilkerbal* *-)

For most classic combustion cars the cost/km is somewhere online. To calculate the cost in comparison you need the - loss of the cars value over the time you use it - cost of a new battery / lifetime of battery or price for the battery lease - cost of charging the car's battery (price/kwh * kwh for charging) - taxes and other fees, insurance - km you drive In the end you'll probably not be surprised that it is more expensive than a combustion car. If you drive a lot and you compare it to a small diesel then the difference is huge and you might want to come back in 3-5 years. My proposal: wait a few years more if your current car still runs. It will get better as more charging stations are built and the big manufacturers one by one switch to electric cars. Batteries get better, drive trains cheaper, etc. Otoh, if your will to own one is too strong then go ahead. When have we ever listened to what mother said (lays down a rose in thoughts) :-) NO ! Cancel that, i misunderstood. I didn't get that you have no driver's license ... don't even think to drive without one !

Funny how fascinating this stuff consistently is. Perpetual machines, reactionless drives, telekinesis, energy for nothing, youth brought back, simple things that nobody has thought of before, ... Those who want to believe do so and rarely can be convinced of their error. Moar evidence based thinking !

Most talk, some do :-)