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72MJ escape velocity, storage for 5 hours on mains

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Andy

Mon Feb 16 2015, 05:14AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Kludgesmith
The ten meter was more vertical size practically, one km might be doable from a hill thought, it needs electrical components and not sure what gees they can handle etcs.

Would say 20,000 g, plus a E motor from a model rocket.

DÃ©dÃ©!

Tue Feb 17 2015, 01:36PM

Registered Member #4932 Joined: Thu May 17 2012, 01:42PM
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The new EMALS (Electromagnetic Aircraft Launch System) for the new Gerald R. Ford Class super Carriers stores the energy needed kinetically on 4 disk alternators. Each rotor can store over 100MJ of energy and can be recharged in 45 seconds.

BigBad

Wed Feb 18 2015, 02:55AM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
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This is a spam launcher.

Spam launchers bore me.

Launch loops are the only way to go.

2Spoons

Wed Feb 18 2015, 09:43PM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
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I just want to point out that your 72MJ assumes 100% energy transfer from storage medium into kinetic energy in the projectile. Good luck with that.

Andy

Thu Feb 19 2015, 02:13AM

Registered Member #4266 Joined: Fri Dec 16 2011, 03:15AM
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Actualy 88% eff, you shoul check the facts first, which would normaly involve asking the OP about details.

2Spoons

Thu Feb 19 2015, 02:34AM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
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Your first post "...store 72MJ..." and " ... 1kg payload"
Your second post " ...12km/s"
1/2MV^2 gives 72MJ in your projectile.
That's 100% transfer.
Facts checked.

I think 88% is pretty optimistic too. Where did you get that figure from?

DÃ©dÃ©!

Thu Feb 19 2015, 07:50PM

Registered Member #4932 Joined: Thu May 17 2012, 01:42PM
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2Spoons wrote ...

I think 88% is pretty optimistic too. Where did you get that figure from?

escape velocity is 11.2km/s. .5*1*11200^2/(72*10^6)*100=~87%

BigBad wrote ...

This is a spam launcher.

Spam launchers bore me.

Launch loops are the only way to go.

That idea of a launch loop is pretty interesting. I weigh about 50kg, so with a launch loop it would cost about $150 to reach outer space. That's a hell of a lot less than, let's say, $200000!

klugesmith

Thu Feb 19 2015, 10:23PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714

Trouble with launch loops is, the cost is just as hypothetical as the technology. STS (Space Shuttle) was originally promoted as getting marginal cost down to $20M (1972) per flight. Total program cost ended up at more than $1.5B (2010) per flight. $200M per astronaut ride. So Soyuz round-trip ticket is a good deal at $50M. Safer, too. (Of course STS did most of the heavy lifting for ISS, and lots of other stuff teh Soyuz couldn't dream of.)

Some net energy values and applications:
1 MJ/kg -- lift to 100 km (Suborbital space tourism).
1.8 MJ/kg -- lift to 179 km (HARP cannon altitude record for 84 kg projectile, in 1966, using a few $1K of consumables).
30 MJ/kg -- LEO at 7.8 km/s, not counting the lift. The target market for launch loops.
63 MJ/kg -- escape from Earth gravity, 11.2 km/s at sea level.

Patrick

Fri Feb 20 2015, 08:49PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

klugesmith wrote ...

Trouble with launch loops is, the cost is just as hypothetical as the technology. STS (Space Shuttle) was originally promoted as getting marginal cost down to $20M (1972) per flight. Total program cost ended up at more than $1.5B (2010) per flight. $200M per astronaut ride. So Soyuz round-trip ticket is a good deal at $50M. Safer, too. (Of course STS did most of the heavy lifting for ISS, and lots of other stuff teh Soyuz couldn't dream of.)

The $20M dollar theoretical operation was so bogus as to be outrageous. ( I wonder if you could even get Ammonium perchlorate for those boosters at 20M$)

In any case, the STS for regular access to space was a disaster, thats why we Americans have gone back to apollo/soyuz method. Any of the heavy lift - high orbit launches like Hubble (which were few and far between) could have been launched with custom rockets cheaper than the excess capability of the Shuttles unused over 20+ years of launches.

The shuttles cost a lot for each launch, and there was alot of capability that couldnt be used to its full potential. In space endeavors, efficiency is important due to high cost and danger.

Modularity is important but its got to be done right.

BigBad

Sat Feb 21 2015, 12:59PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
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Posts: 600

klugesmith wrote ...
STS (Space Shuttle) was originally promoted as getting marginal cost down to $20M (1972) per flight.

They actually more or less succeeded, for flights above the minimum number, the cost did come down to about that, inflation adjusted. Those extra flights were much cheaper.

Of course they didn't launch 50 flights a year, so it was a bit of a pyrrhic victory.

klugesmith wrote ...

Total program cost ended up at more than $1.5B (2010) per flight. $200M per astronaut ride.

That's the average. There#s a difference between marginal and average.

DÃ©dÃ©! wrote ...

That idea of a launch loop is pretty interesting. I weigh about 50kg, so with a launch loop it would cost about $150 to reach outer space. That's a hell of a lot less than, let's say, $200000!

I think the payload wouldn't be just you, so you'd need about a tonne of life support/reentry as well so it would be more like $3000 and even that is very optimistic.

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