A Question About Metallic. Hydrogen... Plus A Realization

[Spacescifi]

Question: Do you think it is or ever will be possible for mankind to create metastable metallic hydrogen? What do you think it would take to do it?

I honestly do not think only pressure is the answer, since once it is released... I don't think the hydrogen will stay compacted.

I presume some kind of binding agent would be required. And if that means a type of EM field it would likely be expensive and require a lot of radiators. It would be better if we could bind it with a matter agent that made it metastable or at least lowered the amount of EM field  power required to keep it metastable.

What do you think?

 

Project Orion Is Not As Good As I Thought:

1. Rockets are cheaper and easier to make.

2. Orion is what you use if you have NO better way.

3. Orion is too dangerous.

4. If the pusher plate misfires too soon you can break the pistons.

5. So heavy that RCS will make turning an issue over time.

6. Has enough bomb power to wipe a country off the map.

 

Why rockets are better:

 

1. Safer.

2. Cheaper.

3. If you wish to combine even FTL jump or warp, rockets, even todays, will work so long you bring rocket tanker ships for ressupply. Tankers ARE your delta V.

 

 

[Scotius]

Finally. Another day, another misguided fan of ORION regained his senses.

If you still have any lingering doubts, remember those two words: Fuel. Cost.

Rocket fuel tends to be dirt cheap compared to the hardware it propels. As it should be, considering how much of it is needed.

If you have sufficiently powerful nuclear engine, any gas or liquid can be fuel.

Hydrogen bombs? They ain't cheap, boyo. Or easy to make. Or store in necessary amounts... without letting the Sun out of the can prematurely Refueling might be a problem too, if your destination point doesn't have a stockpile of H-bombs ready.

Project ORION: awesome on paper. Impractical anywhere else.

[magnemoe]

Yes Orion is dangerous as you setting off nukes near you. 
More an problem its an drive who works better who larger your ship is ship, here is the ocean going ones  
However chemical rockets has an very low dV, yes you might pull off an manned starship mission to Jupiter but that would also be very high risk. 
We need fusion, it would solve so many problems. 
 

[Spacescifi]

1 hour ago, magnemoe said:

Yes Orion is dangerous as you setting off nukes near you. 
More an problem its an drive who works better who larger your ship is ship, here is the ocean going ones  
However chemical rockets has an very low dV, yes you might pull off an manned starship mission to Jupiter but that would also be very high risk. 
We need fusion, it would solve so many problems. 
 

 

True.... my point was if you combine scifi tropes like FTL jump or warp drives with even modern rocketry that would be enough to go to jupiter with rocketry or anywhere else.

Of course it depends heavily on your warp or jump drive being way more efficient than your rockets.... but I digress.

If I recall correctly to the delta v to match Jupiter's orbit from Earth orbit is not high from a delta v standpoint. It's the acceleration long trip all the way there from earth and the retroburn of arrival that kills your propellant.

 

Scifi jump and warp skips that step.

Edited August 6, 2021 by Spacescifi

[Shpaget]

2 hours ago, Spacescifi said:

 

If I recall correctly to the delta v to match Jupiter's orbit from Earth orbit is not high from a delta v standpoint. It's the acceleration long trip all the way there from earth and the retroburn of arrival that kills your propellant.

You may be confused as to what dv actually is.

[GoSlash27]

3 hours ago, Spacescifi said:

If I recall correctly to the delta v to match Jupiter's orbit from Earth orbit is not high from a delta v standpoint. It's the acceleration long trip all the way there from earth and the retroburn of arrival that kills your propellant.

Spacescifi,

You absolutely do *not* recall correctly. I concur with Shpaget's suggestion that you review the subject of "delta v". After that, you'll want to look at the Oberth effect.

Best,

-Slashy

[Spacescifi]

10 minutes ago, GoSlash27 said:

Spacescifi,

You absolutely do *not* recall correctly. I concur with Shpaget's suggestion that you review the subject of "delta v". After that, you'll want to look at the Oberth effect.

Best,

-Slashy

 

Perhaps not.... may not matter though.

 

I know Jupiter orbits slower than Earth does around the sun.

 

Earth orbit around sun speed: 30 kilometers per second.

 

Jupter orbit around sun speed 13.07 kilometers per second.

 

Which means there is less than 16.93 kilometers per second that must be lost to orbit jupiter, since no one wants to drop their whole ship there.

Losing that speed can be done quickly via rocketry or slower via gravity fly bys.

[GoSlash27]

39 minutes ago, Spacescifi said:

 

Perhaps not.... may not matter though.

 

I know Jupiter orbits slower than Earth does around the sun.

 

Earth orbit around sun speed: 30 kilometers per second.

 

Jupter orbit around sun speed 13.07 kilometers per second.

 

Which means there is less than 16.93 kilometers per second that must be lost to orbit jupiter, since no one wants to drop their whole ship there.

Losing that speed can be done quickly via rocketry or slower via gravity fly bys.

Yeah... No. An orbit is composed of both potential energy and kinetic energy. Taking an object at Earth's SMA and removing 17 km/sec simply puts it in an elliptical orbit with a perihelion down below Mercury.

 You can say that a vis-viva from Earth's orbit about the sun to Jupiter's orbit about the sun is about 17 km/ sec and would be more or less correct.  But #1 that is a massive amount of delta v and #2 if you do a transfer from orbit of Earth to  orbit of Jupiter, the total delta v required is only 6.5 km/sec; a tiny fraction of your original estimate.

 So not only do you not realize that the combined velocity changes created by the prograde/retrograde burns are what "delta v" actually is, but you have your assertion completely backwards because you haven't accounted for Oberth effect.

Best,

-Slashy

 

 

Edited August 7, 2021 by GoSlash27

[Spacescifi]

1 hour ago, GoSlash27 said:

Yeah... No. An orbit is composed of both potential energy and kinetic energy. Taking an object at Earth's SMA and removing 17 km/sec simply puts it in an elliptical orbit with a perihelion down below Mercury.

 You can say that a vis-viva from Earth's orbit about the sun to Jupiter's orbit about the sun is about 17 km/ sec and would be more or less correct.  But #1 that is a massive amount of delta v and #2 if you do a transfer from orbit of Earth to  orbit of Jupiter, the total delta v required is only 6.5 km/sec; a tiny fraction of your original estimate.

 So not only do you not realize that the combined velocity changes created by the prograde/retrograde burns are what "delta v" actually is, but you have your assertion completely backwards because you haven't accounted for Oberth effect.

-ISlashy

 

 

 

I was well aware that it is easier to reach outer planets since they are movinf slow anyway... relative to us.

 

Time is the main factor. Matching orbits with rockets is fairly easy.... just depends how fast and how much propellant tankers you want to use up or wait longer.

Matching orbits is still faster and rasier than actually taking the time to coast there.

Edited August 7, 2021 by Spacescifi

[kerbiloid]

The world with delayed delta-V, when the spacecraft "accelerates" by engines, actually staying still, generates delta-V and stores it in a delta-V accumulator, then drifts away with disabled engines, spending the saved delta-V (from the delta-V accumulator) to reach the (circular) orbit matching its final velocity (like a ball in a funnel) is an original sci-fi itself.

[GoSlash27]

3 hours ago, Spacescifi said:

 

I was well aware that it is easier to reach outer planets since they are movinf slow anyway... relative to us.

 

Time is the main factor. Matching orbits with rockets is fairly easy.... just depends how fast and how much propellant tankers you want to use up or wait longer.

Matching orbits is still faster and rasier than actually taking the time to coast there.

spacescifi,

 No, you don't seem to be "aware" of how any of this works. I'm suggesting that you ought to become aware. 

Best,

-Slashy