Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

SpinLaunch is building a centrifuge to launch satellites into orbit

wired.com

Post reply on HN
Print view View original

81–90 of 152 posts

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#81

Post by mlindner »

roamingryan wrote: post #38
ivirshup wrote: post #30

10,000g sounds pretty rough. Are there any existing electronics that we would expect to survive this?

Yes. Guided munitions. Some artillery shells incorporate guidance electronics that survive these sort of conditions.

Yes but guided munitions are compact lumps of steel, not squishy rocket tanks full of liquid. The forces are also all in one direction, first in the positive direction from launch, and then in the negative direction from atmospheric deceleration.

This will have lateral forces, then sudden relaxation of those forces (shock unloading) and then sudden vertical forces when it hits dense atmosphere.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#82

Post by mlindner »

sneak wrote: post #2

How does this prevent the satellite from being damaged when it transitions from 5000mph in vacuum centrifuge to less-than-5000mph-in-troposphere 1 meter later just out of the door? That's gotta be one hell of a fairing.

They're going to need an ablative heat shield or make it out of pure titanium.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#83

Post by jasonwatkinspdx »

pengaru wrote: post #29
jasonwatkinspdx wrote: post #25

Earlier quoted context omitted.

This isn't very appealing to defense either, due to the slow spin up.

This isn't my area of expertise, but judging from some of the extreme physics they're dealing with I'm assuming they're solving problems with potentially lucrative military applications.

They aren't solving anything, and no, there's no potentially lucrative military applications. This is just an investor scam. Dunno if the founders are true believers it or not, but this thing has 0% chance of producing anything interesting.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#84

Post by timpattinson »

hirundo wrote: post #18

1. Build a large superconducting flywheel energy storage system like they have in Japan, right under the launch centrifuge. 2. Use it continually to arbitrage energy prices. Buy low sell high. 3. At launch time divert the rotational energy to the centrifuge. (I'd like to see that clutch.) 4. Profit

5. Forget about the rockets, just buy and sell energy

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#85

Post by bob1029 »

10000g peak forces are a bit of a mess for space travel.

Perhaps instead of directly spinning the object up to speed and "letting go", you could build up all of the energy into a heavy rotating mass which then imparts it into the spacecraft over a slightly longer timeframe via some simple mechanical clutch and cable arrangement. You would still have very strong g-forces, but you could control the impulse curve over time to spread out the forces better.

Steel cables, flywheels and other members aren't going to care about such forces as much as the delicate electronics on board a spacecraft. Let these parts do the heavy lifting and then transmit the energy into the spacecraft in a methodical manner. You need to decouple the extreme nature of this sort of energy storage system from the spacecraft until it is go time.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#86

Post by nitrogen »

piker wrote: post #62
Cthulhu_ wrote: post #58

Earlier quoted context omitted.

Not sure how serious you are with the radioactive waste thing but I'll do the HN thing and bite (nerdsnipe!), because that's not going to work. You can't launch things into the sun, you need to decelerate objects. The earth travels at 30 km / s (70K MPH) around the sun, so you need to decelerate about that much the other way. And orbiting radioactive waste is just asking for trouble. The total amount of radioactive w…

> The total amount of radioactive waste on the earth is about the size of a swimming pool (or was that the total amount of gold? I forgot, either way in terms of quantity it's not that much) This seems wrong in both places. There are probably enough gold rings manufactured per year to fill a swimming pool. In pictures: Fort Knox itself seems to have at least a swimming pool of gold [1] and Thailand a swimming pool of…

Those piles of bars are shallow, and those barrels are probably mostly non-spent-fuel by volume.

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#88

Post by londons_explore »

absolutelyrad wrote: post #78
martey wrote: post #46

The Wired article that this SyFy blurb is based on has more details (and more criticism) - https://www.wired.com/story/inside-spinlaunch-the-space-indu... > One former employee, who spoke on condition of anonymity due to their nondisparagement and nondisclosure contracts, acknowledged the gulf between theory and reality. They described SpinLaunch’s prototype centrifuge as a relatively unsophisticated machine that “an…

Thanks, this is what I was looking for. I didn't want to dismiss them fast, but it did sound like the founders don't know what they're up to. Maybe they figured out some advanced materials science we don't know about, but that seems unlikely from this article. > Over the next few years, the team ran hundreds of high-speed tests. Most of them were to study and improve the system, but some were to mollify skeptical inv…

Assume the screen and top glass of an iPhone are 40 grams.

10000g's will make the effective mass of them 400kg.

Could an iPhone survive 400kg sitting on top of it?

It's definitely within the realm of possibility...

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#89

Post by londons_explore »

bob1029 wrote: post #85

10000g peak forces are a bit of a mess for space travel. Perhaps instead of directly spinning the object up to speed and "letting go", you could build up all of the energy into a heavy rotating mass which then imparts it into the spacecraft over a slightly longer timeframe via some simple mechanical clutch and cable arrangement. You would still have very strong g-forces, but you could control the impulse curve over t…

You very quickly get to multi-kilometer ropes, and the need to accelerate a far higher mass than the launch mass...

Re: SpinLaunch is building a centrifuge to launch satellites into orbit

#90

Post by absolutelyrad »

londons_explore wrote: post #88
absolutelyrad wrote: post #78

Earlier quoted context omitted.

Thanks, this is what I was looking for. I didn't want to dismiss them fast, but it did sound like the founders don't know what they're up to. Maybe they figured out some advanced materials science we don't know about, but that seems unlikely from this article. > Over the next few years, the team ran hundreds of high-speed tests. Most of them were to study and improve the system, but some were to mollify skeptical inv…

Assume the screen and top glass of an iPhone are 40 grams. 10000g's will make the effective mass of them 400kg. Could an iPhone survive 400kg sitting on top of it? It's definitely within the realm of possibility...

The force is acting on internal parts too. I don't think the silicon microchip inside can survive those forces.

There is just too much that could go wrong here.

I would be positively shocked if this thing works. I'd have to rethink a lot of things I hold an opinion on.

Post reply on HN