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A US military exercise to launch a satellite on short notice

arstechnica.com

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Re: A US military exercise to launch a satellite on short notice

#31

Post by kimixa »

zer00eyz wrote: post #28
kimixa wrote: post #23

Earlier quoted context omitted.

No, not even close. The issue is simply exhaust velocity and reaction mass, that leads us into the tyranny of the rocket equation - in that you have to carry that reaction mass with you and accelerate that mass too. Even if you had magic infinite energy - e.g. it's supplied externally by a laser or similar. Using the theorized maximum of 31km/s exhaust velocity of project orion (much higher than any current high impu…

> No, not even close. 10% of C is theoretically possible with a space sail, and lasers. Will it work? Well we don't know cause we haven't tried.

Space sails are super low thrust though, even lower than my VASIMIR example - so will take even longer to reach the desired speed - though they have the advantage of not having to carry the complex and heavy engine I ignored that in the rough estimates anyway.

So by the time they're theoretically close to the desired speed they'll be on the other side of the galaxy at least, even if it took millions of years to get there at the much slower average speed.

Re: A US military exercise to launch a satellite on short notice

#32

Post by amanaplanacanal »

mschuster91 wrote: post #17
ck2 wrote: post #4

Can we swap the US Military and NASA budgets for just one year please? Just one year It would be AMAZING Or even what we fund Israel's 2/3 of all their weapons are bought by US We'd have 10% speed of light probes going outside of solar system already Well at least Nancy Grace Roman L2 Telescope is launching, hope it goes perfectly

> Or even what we fund Israel's 2/3 of all their weapons are bought by US And all of the money the US gives to Israel is earmarked for American products.

Just more American tax dollars going to American defense contractors.

Re: A US military exercise to launch a satellite on short notice

#33

Post by blauditore »

kimixa wrote: post #23
avmich wrote: post #5

Earlier quoted context omitted.

Can we really accelerate any probe to faster than 1% c? Or 2% c?

No, not even close. The issue is simply exhaust velocity and reaction mass, that leads us into the tyranny of the rocket equation - in that you have to carry that reaction mass with you and accelerate that mass too. Even if you had magic infinite energy - e.g. it's supplied externally by a laser or similar. Using the theorized maximum of 31km/s exhaust velocity of project orion (much higher than any current high impu…

And why not accelerate using swing-bys on moons and planets? Of course this gets harder the faster you're already moving, but IIUC Voyager 1 has roughly 0.01% c, and this was launched 50 years ago.

Re: A US military exercise to launch a satellite on short notice

#34

Post by jocaal »

cg5280 wrote: post #8
ck2 wrote: post #4

Can we swap the US Military and NASA budgets for just one year please? Just one year It would be AMAZING Or even what we fund Israel's 2/3 of all their weapons are bought by US We'd have 10% speed of light probes going outside of solar system already Well at least Nancy Grace Roman L2 Telescope is launching, hope it goes perfectly

In 2024, the average American spent about $17,000 on taxes. Nearly $4000 of that went to the DoD, about $3500 went to interest on federal debt. I think it’s fun to think about it in this way. I personally spend hundreds of dollars a month on war.

Funny how people complain about federal debt, when the people complaining benefitted the most from the system. It is your children who will be paying the interest, while the older folk enjoyed a heated economy with high government spending. Economics is just as fundemental as physics. There are conservation laws that cannot be violated. However you can make other people hold the bag.

Re: A US military exercise to launch a satellite on short notice

#35

Post by manoDev »

WarmWash wrote: post #10
ck2 wrote: post #4

Can we swap the US Military and NASA budgets for just one year please? Just one year It would be AMAZING Or even what we fund Israel's 2/3 of all their weapons are bought by US We'd have 10% speed of light probes going outside of solar system already Well at least Nancy Grace Roman L2 Telescope is launching, hope it goes perfectly

The military budget is a jobs program that also keeps a (near bare minimum) level of industrial capacity afloat. Its why no politician left or right is really interested in cutting it. If you browse open contracts, you'll see they that they overwhelmingly buy rather banal things and spend comparatively little on the "killing people" parts.

The military budget is how the US enforces Bretton Woods. The jobs part is just a nice side-effect of any govt. spending.

Re: A US military exercise to launch a satellite on short notice

#37

Post by ck2 »

avmich wrote: post #5
ck2 wrote: post #4

Can we swap the US Military and NASA budgets for just one year please? Just one year It would be AMAZING Or even what we fund Israel's 2/3 of all their weapons are bought by US We'd have 10% speed of light probes going outside of solar system already Well at least Nancy Grace Roman L2 Telescope is launching, hope it goes perfectly

Can we really accelerate any probe to faster than 1% c? Or 2% c?

I think the idea is tic-tac sized probes with nano circuitry (that doesn't exist yet)

accelerated by lasers so they don't have to carry the power source

Obviously stopping is the problem, they can never stop but at some point no need

Re: A US military exercise to launch a satellite on short notice

#38

Post by [deleted] »

blauditore wrote: post #33
kimixa wrote: post #23

Earlier quoted context omitted.

No, not even close. The issue is simply exhaust velocity and reaction mass, that leads us into the tyranny of the rocket equation - in that you have to carry that reaction mass with you and accelerate that mass too. Even if you had magic infinite energy - e.g. it's supplied externally by a laser or similar. Using the theorized maximum of 31km/s exhaust velocity of project orion (much higher than any current high impu…

And why not accelerate using swing-bys on moons and planets? Of course this gets harder the faster you're already moving, but IIUC Voyager 1 has roughly 0.01% c, and this was launched 50 years ago.

[deleted]

Re: A US military exercise to launch a satellite on short notice

#39

Post by adrianN »

alberto467 wrote: post #30
tclancy wrote: post #12

Earlier quoted context omitted.

Great. Can we change it to just be the non killing part for a few years until the bad project ideas fully die off?

No it would obviously lose its purpose then.

You could have a jobs program that builds infrastructure instead.

Re: A US military exercise to launch a satellite on short notice

#40

Post by lstodd »

zer00eyz wrote: post #24
ck2 wrote: post #4

Can we swap the US Military and NASA budgets for just one year please? Just one year It would be AMAZING Or even what we fund Israel's 2/3 of all their weapons are bought by US We'd have 10% speed of light probes going outside of solar system already Well at least Nancy Grace Roman L2 Telescope is launching, hope it goes perfectly

> Can we swap the US Military and NASA budgets for just one year please? It would be nice. There is a pretty well known interview of Admiral Grace Hopper by David Letterman, where she talks about her famous "nanosecond" and explaining (to Generals) why it takes so long to get a message to a satellite. https://www.youtube.com/watch?v=oE2uls6iIEU (As an aside, Grace was a name she lived up to in a way few others could,…

Durum-burum latency. In fact, internets slowed down compared to 2010s, and CDNs helped only to delay that.

LEO orbit latency is nothing compared to what you lose to stuffing your link with useless web crap.

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