Hacker News Reader

Comment by bellyfullofbac | Hacker News Reader

Well, kidnap as it travels over international waters, so, well, that's not exciting, the title can just be "Who Would Kidnap Precious Cargo?" (answer: sea pirates).

I thought it'd be about a telescope already in space, and how some entity managed to send signals to it to move it (from the HTML title as it currently is on my browser: The World's Most Powerful Space Telescope Is Moving). I was wondering what they'd do with it and how they'd hide it. And also why.

Thinking about it, obviously radio comms to (and probably from) the satellite is encryped, I wonder if the Bad Guys could hack into the ground station and steal the encryption key...

View on HN

I don't think there is any need to encrypt traffic coming from the telescope. One of the (many) compromises in the design is using 26Ghz radios that will be so low power that the only way to downlink data is using the huge Deep Space Network.

So many design compromises were forced by not putting nuclear power on the telescope. I really hope it works, but I think the odds of getting much useful science from it slim.

I share your hopes, but I fear the second system effect.

Why not include nuclear power on the telescope?

Would it cause interference?

Almost certainly, yes, it would interfer with the thermal imaging of the scope.

Not my domain, so speculating:

Space-based nuclear power is virtually always a radioisotopic thermoelectric generator (RTG), which works by utilising the heat of radioactive decay from plutonium, in the form of plutonium oxide.

Since the generation mechanism is thermal, the RTG reaches high temperatures (500C, 900F).

The Webb telescope is an infrared telescope, sensing electromatic radiation in the range emitted by warm objects. The telescope itself is cryogenically cooled to 50K (-223C, -369F), and carefully shielded from the Sun by a large (though lightweight and delicate) shade.

Even electrically-powered systems on the cold side of the telescope are designed for the lowest possible power consumption to minimise heating. The instrument package draws 11 milliwatts of power. That's 1 calorie every 6 minutes 20 seconds --- it would take 6.33 minutes to raise 1 ml of water 1 degree Celsius. You burn about 10 calories (10 kilocalories or "dietary calories") in the same time.

https://en.wikipedia.org/wiki/James_Webb_Space_Telescope

TL;DR: thermal generation on an instrument which must be maintained at an extremely cold temperature is a hard engineering problem.

Same, but I'm curious why you think it's encrypted at all? Also makes me curious how resistant to crypto attacks satellites would be, given all the various failings and gotchas with terrestrial tech and tls and others.

I'm curious why you think they'd just leave open the ability to destroy a satellite to anyone with a powerful enough transmitter. The telemetry, tracking and control (TT&C) data is absolutely encrypted for any serious satellite operating today.

You need authentication, not encryption for that. And yes, every satellite's TTM has an AU (authentication unit) nowadays.

> I thought it'd be about a telescope already in space,

(answer: space pirates)

Reply on news.ycombinator.com