• Content count

  • Joined

  • Last visited

Community Reputation

525 Excellent

About Shpaget

  • Rank
    Sr. Spacecraft Engineer

Recent Profile Visitors

2057 profile views
  1. Yeah, it is a lot of nines, but I had to put that many to get into the blueshift-to-gamma ballpark. Subterranean nuke is a tricky approximation, sure, but I have no idea how to calculate the penetration depth of the particle in question, so I just took a data point that was available to me. As for the rest, of course, one approximation on top of another, but in each step I took took the less dangerous end of approximation, and rounded up or down towards a less cataclysmic scenario. In any case, I believe that 0,999999c is just as unachievable as 0,9c is.
  2. 100 GW shining on a circle with 10 km diameter delivers 1270 W per square metre. That is quite close to the radiation coming from the Sun (1370 W/m^2 in orbit, 1100 on the surface), so it would get quite hot - nice summer day hot, not counting the Sun. Combined with Sun, it could definitely start forest fires and cause sunburns - the Sun alone does that. The same 100 GW beam shining on a 100 m radius is another story. Can you say death ray?
  3. It's not easy to trigger a nuke.
  4. Perhaps, but you only trade kinetic energy for thermal. Total is the same.
  5. That would only add the energy of the laser to the energy of the particle. Double the trouble.
  6. Hmmm, I wonder how long it would last. Let's go and do the math! I'm doing the calculation and googlinglive as I type, so I don't know what result will I get. First, let's figure out the kinetic energy of a typical micro particle found in the interplanetary space. They are usually under 100 micrometers, so, let's take 50 um. The volume of sphere of that diameter is 6.545x10^-14 m^3, with the average M class asteroid density of around 5 g/cm^3, that brings us to the mass of 3,27x10^-7 kg. So, the kinetic energy of that particle at 0,999999c would be 2,07x10^13 J, which is roughly equivalent to a 5 kt nuke, which is a modest sized tactical nuke. Now, let's see how often would our spacecraft be struck by such particle. I'm having trouble finding the data on the frequency of such particles in space but I did find the estimate that Earth is struck by 37,000-78,000 tons of the stuff each year. Let's take the low number of 40 000 tons, or 40 000 000 kg per year. There would be roughly 120 000 000 000 000 particles that hit the Earth in such a scenario. If we take our spaceship to have a rather tiny cross section of just 200 m^2, that means, our ship would be struck around 180 times in one Earth orbit, which it would cover in just under an hour. This article states that a 104 kt (subterranean) bomb excavated 11 000 000 tons of material, so our 20 times smaller bomb would dig up 500 000 tons. To reach our 60 gigatons mark, we would need 120 000 strikes, which would occur in roughly 25 days. Shield not heavy enough.
  7. Here's my attempt to capture the Big J from way back in 2012. If you squint and follow a line from the planet to the lower left corner you might see two dots. Those are Io (the one closer to the planet) and Ganimede (near the corner). When I set out for some night photography, all I had with me was two DSLRs, a bag of lenses and a tripod. I took my motorcycle and crossed a local mountain, so that I can at least put the mountain between myself and all the light pollution from the city. So, there I am, in the middle of nowhere, halfway down the wrong side of a mountain (no big towns anywhere near), in pitch black night, on a road that sees little traffic even during the day, clicking my long exposures when suddenly a pair of xenon lights turn around a corner and mess up my shot. Ah well, memory card space is cheap :). But, the car stops just by my side and a bunch of guys start pouring out. "Whazzup!" "Hey" "What ya doing" "Shooting stars" "Did we mess up your shot?" "No biggie"... Long story short, these guys start unpacking this huge telescope out of the trunk of the car. Great! More small talk and they seem cool enough so I kind of attach myself to their eyepeice. They have some trouble with polar alignment, but eventually they turn the scope to Jupiter. Of course, they don't have the adapters to mount my camera on the scope, so I take the picture above afocally, handheld, hence the shake. Unfortunately the camera didn't catch Callisto that was just outside of the frame.
  8. Once you get to five or six nines, you'd be facing quite a bit of gamma radiation from all the blueshifted starlight. Come close (astronomically speaking) to a star, and you're zapped. No worries, though. Dust particles will nuke you long before that.
  9. For the time to be a loop, there would necessarily need to be another time dimension in which that loop would occur. Is that dimension also a loop, but on a bigger scale? That would require yet another dimension. Where does it stop?
  10. To me KSP is primarily a game, which means that, above all else, it needs to be fun. So if I think that a legit correction of a problem is going to be tedious, I cheat, be it F5 or cheat menu. If I think that the legit way of correcting the problem is going to be fun, I go the legit way and pretend that the mission parameters have changed. If the problem is caused by a technical issue, a bug, or similar, I usually reload/cheat. I find no amusement in crashes (as rare as they happen to me in KSP). It all depends on the mood, I guess.
  11. Fine by me. They all fall in the group of suborbital vertical landing systems and none of these mentioned were the first.
  12. We all realize that F9 is a whole lot bigger, but the level of complexity of electronics and software for navigation/guidance, attitude, control and ultimately powered landing is basically the same no matter the size - and that is the most important aspect of powered landing.
  13. Which is still a lot less than energies involving orbital speeds.
  14. F9 first stage does not deliver payload to orbit, it's the second stage that is responsible for almost 80% of the total speed. At the moment of staging, the first stage is traveling at 1660 m/s (in the specific case of CRS-10), which is not a whole lot faster than New Shepard (aprox. 1300 m/s).
  15. Care to expand on your calculation?