hanelyp wrote:
As far as I'm concerned it's not a question of whether such 'hibernation' tech is possible, but how soon, and how much it extends permissible transit time. There have been some intriguing animal studies using hydrogen sulfide. It appears that there are mechanisms built into animal metabolism to enter a reversible shutdown state in an oxygen free environment. The trick is triggering those mechanisms in a controlled fashion.
I read an article some years ago on Scientific American about hibertantion with hydrogen sulfide at the concentration of 1 ppm.
Is very interesting, but if Bussard's Polywell will function, I think is not necessary hybernation to travel in the solar system, unless you want to go in the Oort Cloud.
With an ARC/CSR hybrid with a maximal exaust velocity of 500 km/s and a mass ratio of 3.5 you will have a delta-v of 626 km/s. So you can accelerate up to 300 km/s, coast for 40 AU in 7.7 month, decelerate and use the rimanent 26 km/s to match the orbital velocity and dock.
Hybernation is interesting for travelig in the near sun extrasolar systems with a DFP engine or a nuclear pulse propulsion. Such kind of ship can reach the Oort Cloud in 50 years and Alpha Centauri in almost 200 years...
hanelyp wrote:
As far as I'm concerned it's not a question of whether such 'hibernation' tech is possible, but how soon, and how much it extends permissible transit time. There have been some intriguing animal studies using hydrogen sulfide. It appears that there are mechanisms built into animal metabolism to enter a reversible shutdown state in an oxygen free environment. The trick is triggering those mechanisms in a controlled fashion.
I read an article some years ago on Scientific American about hibertantion with hydrogen sulfide at the concentration of 1 ppm.
Is very interesting, but if Bussard's Polywell will function, I think is not necessary hybernation to travel in the solar system, unless you want to go in the Oort Cloud.
With an ARC/CSR hybrid with a maximal exaust velocity of 500 km/s and a mass ratio of 3.5 you will have a delta-v of 626 km/s. So you can accelerate up to 300 km/s, coast for 40 AU in 7.7 month, decelerate and use the rimanent 26 km/s to match the orbital velocity and dock.
Hybernation is interesting for travelig in the near sun extrasolar systems with a DFP engine or a nuclear pulse propulsion. Such kind of ship can reach the Oort Cloud in 50 years and Alpha Centauri in almost 200 years...
Depends on how much fuel you have. Fission Orion pulse-det gets you to 8-10% of C (a Cent in 45 years), Daedelus fusion pulse-det gets you 12-15% of C (a Cent in <30 years), given the designs at hand. D-T Polywell could do significantly better, 16-20% C (a Cent in 20-30 years), possibly act as a boost phase to reach Bussard Ramjet velocities (which gives us a Cent in under 5 years).
And yes, interstellar travel is what we are talking about. Mars may be terraformable with several decades work. If the TPF detects earth-like planets around Alpha Centauri B as predicted, then all bets are off.
Depends on how much fuel you have. Fission Orion pulse-det gets you to 8-10% of C (a Cent in 45 years), Daedelus fusion pulse-det gets you 12-15% of C (a Cent in <30 years), given the designs at hand. D-T Polywell could do significantly better, 16-20% C (a Cent in 20-30 years), possibly act as a boost phase to reach Bussard Ramjet velocities (which gives us a Cent in under 5 years).
And yes, interstellar travel is what we are talking about. Mars may be terraformable with several decades work. If the TPF detects earth-like planets around Alpha Centauri B as predicted, then all bets are off.
As a medical doctor (this is my job) I think is not realistic to ibernate in hydrogen sulfide for 30-250 years, without any kind of cryopreservation. But we can think that in a near future we can maage to modify human been to have a longer life or to self-hybernate...
I have another question about Dr. B'DFP engine: with a secondary magnetically insulated diulition chamber put after the diverter coils, may be possible to reach higer diluition rate (near 1:500,000) to lower the exaust velocity up to 16 km/s and allow the DFP to funcion also in high thrust modality for impulsive orbital manuvering?
Depends on how much fuel you have. Fission Orion pulse-det gets you to 8-10% of C (a Cent in 45 years), Daedelus fusion pulse-det gets you 12-15% of C (a Cent in <30 years), given the designs at hand. D-T Polywell could do significantly better, 16-20% C (a Cent in 20-30 years), possibly act as a boost phase to reach Bussard Ramjet velocities (which gives us a Cent in under 5 years).
And yes, interstellar travel is what we are talking about. Mars may be terraformable with several decades work. If the TPF detects earth-like planets around Alpha Centauri B as predicted, then all bets are off.
As a medical doctor (this is my job) I think is not realistic to ibernate in hydrogen sulfide for 30-250 years, without any kind of cryopreservation. But we can think that in a near future we can maage to modify human been to have a longer life or to self-hybernate...
Ok, but how about one year in hibernation, one year in active state, switching back and forth?
Cryopreservation is not going to be a viable suspension means, it causes too much cellular damage. Without advanced nanotechnology and mind uploading capabilities, cryopreservation is just making corpsicles.
Drug induced hibernation/coma with a cool-down to an above-freezing temp and minimal metabolic activity with active automated systems monitoring is really the way to go.
Quaoar wrote:I have another question about Dr. B'DFP engine: with a secondary magnetically insulated diulition chamber put after the diverter coils, may be possible to reach higer diluition rate (near 1:500,000) to lower the exaust velocity up to 16 km/s and allow the DFP to funcion also in high thrust modality for impulsive orbital manuvering?
Thanks to all
Quaoar
For high thrust what you would do is dump a lot of hydrogen through cooling coils around the reactor and use the heated hydrogen for thrust. This mode really would not be necessary for anything but launch and/or moving from orbit to escape velocity on time sensitive missions.
For high thrust what you would do is dump a lot of hydrogen through cooling coils around the reactor and use the heated hydrogen for thrust. This mode really would not be necessary for anything but launch and/or moving from orbit to escape velocity on time sensitive missions.[/quote]
I need a long range warship for power projection at the edge of the solar sistem (is for an SF novel). So I think to adapt a DFP drive to function also in high thrust - low specific impulse (10000-1500 s) modality for fighting manouver, instead to use an ARC-CSR hybrid that is limited in maximal specific impulse.
Another possibility is a very huge DFP carriership to bringing far some little fighting ARC corvette...
There is a lot a possibility but I want to build quite realistic spaceship for my novel.
Quaoar wrote:I have another question about Dr. B'DFP engine: with a secondary magnetically insulated diulition chamber put after the diverter coils, may be possible to reach higer diluition rate (near 1:500,000) to lower the exaust velocity up to 16 km/s and allow the DFP to funcion also in high thrust modality for impulsive orbital manuvering?
Thanks to all
Quaoar
For high thrust what you would do is dump a lot of hydrogen through cooling coils around the reactor and use the heated hydrogen for thrust. This mode really would not be necessary for anything but launch and/or moving from orbit to escape velocity on time sensitive missions.
That is the way I see it too. H2 for SSTO. To make that work with reasonable safety I see using a maglev slingshot for initial acceleration. Dumping tons of H2 around a launch pad during lift off does not seem to be the wisest move.
Engineering is the art of making what you want from what you can get at a profit.
IntLibber wrote:Depends on how much fuel you have. Fission Orion pulse-det gets you to 8-10% of C (a Cent in 45 years), Daedelus fusion pulse-det gets you 12-15% of C (a Cent in <30 years), given the designs at hand. D-T Polywell could do significantly better, 16-20% C (a Cent in 20-30 years), possibly act as a boost phase to reach Bussard Ramjet velocities (which gives us a Cent in under 5 years).
IIRC the Bussard Ramjet is ruled out in the Local Bubble because the density of the interstellar medium is too low.
IntLibber wrote:And yes, interstellar travel is what we are talking about. Mars may be terraformable with several decades work. If the TPF detects earth-like planets around Alpha Centauri B as predicted, then all bets are off.
Doubt it. Immediate resource payoffs in the Solar System vs a throw of the dice for extrasolar colonies.
Quaoar wrote:I need a long range warship for power projection at the edge of the solar sistem (is for an SF novel). So I think to adapt a DFP drive to function also in high thrust - low specific impulse (10000-1500 s) modality for fighting manouver, instead to use an ARC-CSR hybrid that is limited in maximal specific impulse.
Another possibility is a very huge DFP carriership to bringing far some little fighting ARC corvette...
There is a lot a possibility but I want to build quite realistic spaceship for my novel.
First class minds attempting to merge real science and hard scifi. The kibitzers behind the "Atomic Rockets" site.
You may want to abandon your interest in Bussard QED drives. Review the "Engine List" page at Atomic Rockets.
Various "weights" of "space warship" are improbable. If a small flotilla of warships can't overwhelm an immobile station, the warships are useless. If your DFP ship can get within engagement range (see "ravening death beams" at the Atomic Rockets site), ARC ships are wasted mass. Armor the DFP ship in slag and turn it into a barely mobile battle station. Thrust matters in the inner system where a ship can dodge behind a planet for shelter & such. Out in the Kuiper where you're interested, dv matters, and the low accel "DFP" ship will eventually run down the high accel ship.
Quaoar wrote:
With an ARC/CSR hybrid with a maximal exaust velocity of 500 km/s and a mass ratio of 3.5 you will have a delta-v of 626 km/s. So you can accelerate up to 300 km/s, coast for 40 AU in 7.7 month, decelerate and use the rimanent 26 km/s to match the orbital velocity and dock.
For your story, make sure you realize that this is not exactly how you would get to the Oort cloud. In CSR mode you will be accelerating at very low thrust, spiraling outward. In electric propulsion, the manuever is called a non-impulsive burn. The calculation is simple if your starting and target orbit are both circular, but thats not what you are talking about. However, I can say that you will either need more fuel or to take longer than assuming a straight line trajectory.
Jeff Peachman wrote:
For your story, make sure you realize that this is not exactly how you would get to the Oort cloud. In CSR mode you will be accelerating at very low thrust, spiraling outward. In electric propulsion, the manuever is called a non-impulsive burn. The calculation is simple if your starting and target orbit are both circular, but thats not what you are talking about. However, I can say that you will either need more fuel or to take longer than assuming a straight line trajectory.
Dr. B's spaceships are in gigawatt range, so even at high specific impulse the thrust is not very low as a solar panel powered ion thruster like New Dawn probe. For example, a CSR speceship of 600 tons, with a 15 GW CSR rocket setted at an exaust velocity of 500 km/s has an initial acceleration of 0.1 m/s2 and can reach a cruising speed of 250 km/s in 23 days of continous thrust, and travel to the Kuiper Belt on hyperbolic trajectory in almost 10 month.
Jeff Peachman wrote:Well there will still be a nice big curve in your trajectory =)
Shure. I'm not an expert, but I think, that in the acceleration phase is initially an ellipse. The eccentricity of the ellipse will increase untill the curve will become parabolic and after hyperbolic.
For short travel in ARC modality, in the Saturn's moon system for example, trajectory will be bitangential ellipses (Hohmann Orbits) or more rapid monotangential ellipses.