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> ion thrusters powered by krypton > autonomously perform maneuvers to avoid collisions with space debris and other spacecraft Pretty cool. Also, the north a
by programmarchy 7y ago
> ion thrusters powered by krypton
> autonomously perform maneuvers to avoid collisions with space debris and other spacecraft
Pretty cool.
Also, the north and south pole are conspicuously avoided by Starlink, confirming my suspicions about the locations of intergalactic space ports.
- downrightmike 7y agoThose are actually where the secret entrances to the Lizard people's land are at.
- HNLurker2 7y agoYes and flat Earth conspiracy about the south poll and North Pole
- M4v3R 7y agoThis sentence reads like science fiction. I had to google “krypton ion thrusters” to make sure it wasn’t a joke. It seems it was not. Very cool.
- shmerl 7y agoWhere do they get more krypton? Or they have limited fuel?
- ls612 7y agoLimited fuel. Thing is that ion thrusters have very very high specific impulse so you get a lot of oomph from them, especially if all you are doing is LEO stationkeeping.
- wtallis 7y agoLimited fuel, but ion thrusters are at least an order of magnitude more efficient (specific impulse) than the usual chemical propellants. The downside is low thrust, but these satellites can be patient when maneuvering between orbits.
- programmarchy 7y agoI think they have limited fuel. According to the site, at the end of life, the satellites de-orbit. Maybe they will be recovered and recycled, too? Either way, the Starlink grid needs to be replenished with new satellites from time to time.
- nordsieck 7y ago> the satellites de-orbit. Maybe they will be recovered and recycled, too? They definitely de-orbit. Half of the reason their orbit is so low is to ensure that they de-orbit quickly once they are out of fuel (the other half is latency).
- dsl 7y ago> the satellites de-orbit. Maybe they will be recovered and recycled, too? Deorbit is a fancy word for burn up in the atmosphere. They are within earths gravitational pull, so if they have a hard failure or run out of fuel to the point they can't "push back" they get vaporized on reentry. It's a clever fail safe.
- Tuna-Fish 7y ago> They are within earths gravitational pull Every satellite going around earth is "within earth's gravitational pull". The starlink satellites are so low that they are inside the rarefied upper layers of the atmosphere, meaning they have low but constant drag pulling on them. When they stop thrusting, they will eventually fall out of the sky.
- varjag 7y agoLEO satellites deorbit due to friction with residual atmosphere, not because of gravitational pull. Orbiting already means you are in an equilibrium with gravity.
- s_y_n_t_a_x 7y agoFuture versions will burn up in the atmosphere, as required by the FCC as SpaceX couldn't guarantee the satellites could be contained to sea landings.
- Thlom 7y agoLimited fuel. Intelsat just lost a satellite due to sudden fuel loss. A big part of satellite management is fuel conservation.
- lmm 7y agoLimited propellant (not fuel - they're not burning the krypton for energy, they'll have some electrical power source, presumably solar panels).
- elamje 7y agoI didn’t realize krypton was a fuel source. I thought Elon put in an easter egg, only to be disappointed by my ignorance.
- SECProto 7y agoIt's not a fuel, it's a propellent (simply put, solar electric is used to accelerate the Krypton out the end of the thrusters)
- wtallis 7y agoThe krypton isn't being used as a chemical reactant, and in fact being largely chemically inert is a benefit for ion thrusters. I suspect they're using krypton instead of xenon due to the latter being more expensive, even though the higher atomic mass of xenon would be beneficial.
- Tuna-Fish 7y agoLower atomic mass gives better Isp, although for power-limited situation you usually want to maximize thrust instead. In the pre-flight press conference the topic of krypton thrusters came up, and at first he made a superman joke, but then said the real answer was the lower cost of krypton.
- isolli 7y agoWhat does "Isp" stand for?
- KAMSPioneer 7y agoProbably meant specific impulse. https://en.wikipedia.org/wiki/Specific_impulse https://en.wikipedia.org/wiki/Specific_impulse
- ProblemFactory 7y agoIt stands for Specific Impulse, which is a measure of fuel economy for rocket engines.
- siquick 7y ago> Also, the north and south pole are conspicuously avoided by Starlink, confirming my suspicions about the locations of intergalactic space ports. Are you saying that there will be intergalactic space ports at the poles in the future?
- ceejayoz 7y agoThere are various wacky conspiracy theories about Nazi remnant and/or alien UFO bases at the poles. https://en.wikipedia.org/wiki/Nazi_UFOs https://en.wikipedia.org/wiki/Nazi_UFOs
- justusthane 7y agoHollow Earth is another bizarre one: https://www.reddit.com/r/hollowearth https://www.reddit.com/r/hollowearth
- tomp 7y agoAlso, > Starlink is the first krypton propelled spacecraft ever flown. So they're using non-flight-proven technology (Technology readiness level at most 6)... impressive!
- Kye 7y agoThey might have gotten launch costs so low that a live test with the possibility of doing it over was cheaper than expensive test runs. Another comment mentioned SpaceX was close to losing some key license. Launching too late was probably going to cost more than the worst-case scenario cost of launching early.