Search found 227 matches
- Sun Jan 01, 2012 2:23 am
- Forum: News
- Topic: Room-temperature superconductivity?
- Replies: 1893
- Views: 720868
You are avoiding logic and distorting the truth Tom. You yourself have claimed that the ages will be determined by which twin returns to which twin. This is a loose statement, but yes, if the twins meet up again relative ages depend on there previous movements. Tom, if I recall correctly you say th...
- Sat Dec 31, 2011 2:32 am
- Forum: News
- Topic: Room-temperature superconductivity?
- Replies: 1893
- Views: 720868
I'm starting to think that those involved in this discussion are not answering each other arguments. A little question to both parties. Ender and Peter Wiggin are brothers. Peter stays on Earth while Ender makes multiple trips between solar systems at near-light speed. After some years Ender stops i...
- Tue Nov 29, 2011 10:36 pm
- Forum: General
- Topic: Climategate II -
- Replies: 23
- Views: 9431
- Tue Nov 29, 2011 1:08 am
- Forum: General
- Topic: Climategate II -
- Replies: 23
- Views: 9431
- Mon Nov 28, 2011 2:10 pm
- Forum: General
- Topic: Climategate II -
- Replies: 23
- Views: 9431
I just cut my hand. It's not a big cut but I've been told that there's always a possibility of gangrene, even from minor wounds, a life threatening condition. What should I do? Will cleaning it with a bit of a disinfectant be enough? Maybe I should go to hospital and ask to stay a few days, just in ...
- Sun Nov 20, 2011 9:10 pm
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
There are some striking similarities between SpaceX and Blue Origin. Both were founded by internet big shots, Jeff Bezos from Amazon (CEO), and Elon Musk from PayPal (co-founder). Both say one of their main goals, at least as an intermediate step, is to significantly cheaper access to space. Even on...
- Sun Nov 20, 2011 4:25 am
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
Even at the lesser performance of kerosine-LOX that sounds like a SSTO with useful payload mass ratio. Certainly. With a mass ratio of 30 and an Isp of 280 s you can get to orbit, but with almost zero margin for payload. 290 s would be much better. It'd imply 15 mt to orbit (from 400 at lift-off). ...
- Sat Nov 19, 2011 10:20 pm
- Forum: General
- Topic: Russian hackers burn out Illinois public water system pump
- Replies: 17
- Views: 5562
What idiot connects crucial facilities like these to the internet? You'd be surprised. I teach network systems security and computer forensics, and quite often wonder how public and private sector alike, can be so reckless with their systems. Looks like too few are able to learn without getting bea...
- Sat Nov 19, 2011 10:06 pm
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
Two small bits of data. 1. From the FH info on Spacex's website, its liquid boosters have a wet/dry mass fraction over 30. Because those boosters are essentially Falcon 9 (block 3?) first stages, that means they have to have about the same ratio. If FH wet mass at lift-off is 1.400 mt and 53 mt are ...
- Wed Nov 09, 2011 3:15 pm
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
Charliem, I think (not sure), that the LES thrusters will replace some of the OMS thrusters on the dragon capsule and they will end up having a dual function. I still think you are way overestimating things here. Just think about it. There have been very serious VTOL SSTO designs that use powered l...
- Wed Nov 09, 2011 12:37 pm
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
I've also been giving some thought to the launch escape / powered landing system for the Dragon capsule, and it doesn't look easy. It implies a quite high weight penalty. At lift-off a Dragon weights 10.2 mt (4.2 dry weight plus 6.0 of payload) and at landing 7.2 mt (4.2 dry plus 3.0 payload). In ca...
- Wed Nov 09, 2011 10:17 am
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
Too many unknowns to determine what happened to the first stages from the F9 flights one and two. I wonder if SpaceX got enough telemetry from them during reentry, if at all. From their declarations looks like they didn't. I suppose they'll rig the next few launches with more sensors and recording g...
- Sun Nov 06, 2011 11:21 pm
- Forum: General
- Topic: Please, Try to Make a Lovely Peaceful World
- Replies: 317
- Views: 61049
everyone in the world hate of bullying Everyone but the bullies. Iran's leadership, by their declarations, seem a bit too sure of their superior moral position. If combined with no allergies to using violence that's dangerous. The eternal lie: "the end justifies the means". You can't undo an injust...
- Sun Nov 06, 2011 10:28 pm
- Forum: General
- Topic: Science And Psuedoscience
- Replies: 16
- Views: 4590
In the end it's just a question of whether scientists can elude human mind's limitations. Some, very few, are humble enough to know how difficult that is, and courageous enough to try their best, and even so there's no guarantee. Most are not that intelligent and think they are free from irrationali...
- Sat Nov 05, 2011 2:37 pm
- Forum: General
- Topic: Space X to build reusable launch vehicle
- Replies: 390
- Views: 117772
I,ve been thinking about the possibility of some kind of air brakes for Falcon9-1st. For example using an inflatable structure around the top of the stage, a ballute, kind of. It'd increase its specific area, modify its drag coefficient, probably enhance its stability, and maybe even give it a bit m...