UmbralRaptor

This is a moderately common convention in various physics texts. I think it ends up being easier to typeset than getting the arrows and hats over the vectors right?

It covers a reasonable amount of topics. Perhaps more importantly it's the only textbook I've seen where the US edition is reasonably priced. >_>

These can get somewhat involved, and admittedly wikipedia doesn't always have things in the best format. The (ahem) textbook answer is Fundamentals of Astrodynamics. If you're looking purely for an online resource, @Ohiobob has done good work.

The instruments are for fulfilling specific missions. (Exact type of instrument falls under the cost/weight issues you bring up, but first one needs a question to answer.)

Yes, we have an IRC channel (#KSPOfficial on irc.esper.net). Please don't just jump in, say "hi" (or at best ask if you can ask a question), and leave after ~45 seconds. Say something of substance, and understand that it may take a few minutes. We aren't paid tech support, and can't be watching 24/7. Also, if we answered your question, feel free to stay and talk about other KSP (or quasi-related) things?

I'm going to assume that the aforementioned Hubble images of Pluto are acceptable (ie: built up from a light curve). In that case, you want a space telescope with a starshade to get something earth-like (eg: HabEx, especially as the WFIRST proposals seem mostly dead.) The earliest plausible time is probably the 2030s, but delays are possible. We'll know more once the 2020 decadal survey is finished.

It's suggestive, but not conclusive of Planet 9. Still a neat object, and apparently stable for some amusing solar system configurations. The paper is on ArXiv, and remarkably readable. There's a decent amount of sky left to search.

The paper is currently open access. I'd recommend checking it out, since even if you can't follow all the fancy statistics there's interesting commentary. eg:

It is used on satellites (eg: WISE)

Cryogenics get you ~25-50% higher specific impulse than hypergolics, which can ease design considerations greatly. More subtly, the propellants easiest to mine/produce on the Moon would be cryogenic in nature. I would also strongly recommend against using hyperbole to power your rocket, as that tends to leave us stuck with fantasies instead of space travel. Insert other media

Replying to myself because in this case bumping is worthwhile. I resorted to temporary IP blocks because, well, https://photos.app.goo.gl/FmR47pxyRNfR9VRb8

As in hover over the pole? It's not an orbit, but cleverly exploiting things that aren't gravity can help: https://en.wikipedia.org/wiki/Statite

Yeah, this was the second major spam attack in a week. The IP block should have expired now?

I'm going to blame implementation of the whole EULA thing. It apparently does some cookie thing that sometimes gets blocked by ad blockers, especially on first hitting the page. Try messing with that, and if you're still getting logged out, email the support staff. (Slow response may be in part due to grad school)

Apparently the popup breaks signing up for a new account (I just got an email from a user who wanted to contribute, but was stopped by that.)

I'm not sure what this counts as, but probably a negative review.

And now I can download successfully. Solution: wait a 12-24 hours?

Currently not even getting the proper download page. Log in, select account, select download, get bounced to the main page of the website. ...try emailing support?

Not sure on the details, but you should probably email support about whatever they're doing with the servers.

RL10 because it's an underappreciated workhorse. High Isp, and used on upper stages on some version virtually all US launchers. But HiPEP deserves an honorable mention. Double the Isp of VASIMR at equal or better energy efficiency, and bench tests ran for at least 1000 hours (vs maybe 15 seconds).

Podcats: - Omega Tau (English and German, fairly technical. Also one of the few cases where multi-hour episodes are worth it.) http://omegataupodcast.net/ - Science Friday https://www.sciencefriday.com/ - Planetary Radio http://www.planetary.org/multimedia/planetary-radio/ - Astronomy Cast http://www.astronomycast.com/ Blogs (sort of): - Astrobites https://astrobites.org/ - The Space Review http://thespacereview.com/ I'm tempted to suggest something like the Galaxy Zoo or Sloan Digital Sky Survey Blogs, or AAS Nova, but those might not be quite what you want?

Soyuz-U. Records include: most launches (786), most successful launches (765), most launches in 1 year (47 in 1979).

Putting enough sulfur hexafluoride or the like into the air to initiate a runaway greenhouse would be far less hassle.

This feels a bit /r/theydidthemath/, but... Lorentz factor at 0.5 c is γ = 1/sqrt(1-0.5^2) = 1.1547 Relativistic momentum is γmv = 1.1547 * (5.98e24 kg) * (149896229 m/s) = 1.03505e33 kg*m/s Relativistic kinetic energy is (γ-1)mc^2 = (1.1547-1) * (5.98e24 kg) * (299792458 m/s)^2 = 8.314467e40 J Using 4.184e9 Joules == 1 ton of TNT equivalent, this is ~2e13 exatons. That's probably not too meaningful, so let's consult the boom table. Approximating the sun as an equal density sphere (very wrong, but I'm unsure of a good estimate of the density profile and this should give a decent lower estimate), the gravitational binding energy is 3 * (6.674e-11 m^3/kg/s^2) * (1.9891e30 kg)^2 / (5 * 6.9578e8 m) = 2.3e41 J. Assuming a perfectly inelastic collision, I get a change in velocity of 521 m/s. An elastic collision would be, uh, silly. But if one could efficiently transfer kinetic energy, the sun could be accelerated to close to 300 km/s. Overall, total energy release is comparable to a nova (not supernova), though it'll probably be way different in detail. Compression as the planet hits the sun will cause fusion, but beyond that I'm hesitant to say much. The sun will I think survive, but don't expect Earth to remain habitable.