New Mars Forums

An Oct. 21 letter from Congress to O'Keefe told NASA to stop spending so much energy on OSP. Several congressman supported Zubrin in the senate committee hearing this morning, although I missed most of the hearing. Zubrin's testimony is on the website. He condemned OSP and called for $60 million for two separate groups to design a Mars mission, He has called for that before but they are probably more receptive now.

http://www.spaceref.com/news/viewnews.html?id=892
"The final result may be a presidential announcement of the new space goal in a national address at Kitty Hawk, North Carolina on December 17, 2003, the 100th anniversary of the Wright Brother's first heavier-than-air powered flight.

According to sources familiar with the White House review, the current plan-subject to change at any time the sources say-is for a final recommendation to the president by November 30th "or shortly thereafter", followed by insertion of the goal into the speech and development of timetables and supporting budgets. "
"As of late October, sources indicate that a central recommendation is likely, but not certainly to be resumption of manned lunar flights to develop advanced technologies that can support U.S. astronauts working beyond Earth orbit to not only the Moon, but eventually on near-Earth asteroids and Mars. "
"In an early phase of the meetings, manned Mars expeditions were considered too expensive and risky to adopt as a central goal for the civil space program. But Bush is being urged to factor in future interplanetary manned flight capabilities as part of the justification for a return to the moon."

Correct me if I'm wrong, but it seems to me that quantum mechanics states that the wave function tends to be wavelike, but it describes the position, momentum, etc. of a point particle. So there's nothing mysterious about that, right? We might set up a potential to diffract light, which seems very wavelike, but the wavefunction will just give us the state and probabilities of point particles. Or is there something else that makes the duality hazy somehow?

ROUND 2:

The Mars Society web page tells us that John McCain read Zubrin's op-ed and has called him to testify. O'Keefe and some others will also be testifying Oct. 29. So maybe O'Keefe will have defend himself.

That's an interesting idea, but you'd have to leave the engine on -- and hope against hope you don't run into any problems. I wouldn't want to get caught with an excess of 30 km/s inbound to  Jupiter and fly straight out of the system.

Well, magnetic fields don't suddenly disappear, certainly, not in the timeframe of a disruption event. Actual loss of confinement is a process wherein instabilities occur and the thermal energy might be deposited in less than 300 ms. The FIRE reactor will be able to detect almost all of those disruptions ahead of time to mitigate the effects (I read something about 280 m/s water jets, actually).

This has some info:
http://www.et.anl.gov/sections/cph/rese … d_hpi.html

In light of the countless pulsed magnetic confinement reactors that have been operating for decades, loss of confinement is certainly not something that causes catastrophic damage. It happens a lot. It's mostly a problem that causes a few mm of the inner wall to be evaporated over the lifetime of the reactor, something which will happen much more infrequently when the technology is more perfected and steady-state.

It takes a fission reactor to get all of this going, but in the steady state, you might sap some of the fusion rocket's power and convert it to electricity so that some of it's output is used to keep it going.

A mirror-type fusion rocket might need 10-100MW of power*.  This would come from a smallish nuclear reactor, and waste heat from the fission reactor and engine would be radiated by large panels or a liquid droplet radiator. In the steady state, the engine could replace the fission reactor as the power supply. If we are burning D-3He, we could convert some percent of the fusion power at >90% efficiency (easily) to electrical power which would run the ship and engine.

A pulse fusion rocket might use small quantities of antimatter, or if driven by lasers, a small fission reactor would give electricity and power capacitor banks.

Soph, you are misunderstanding the hydrogen propellant concept for fusion: You can add hydrogen flow rate, which means you can simultaneous lower the Isp and increase the thrust, in a continuum. There may be some engineering limits on how exactly this is done.

This plasma sail stuff is much simpler. When I have the time I'll read more about it, though, since I wonder about the performance limits. There is a proposed M2P2 interstellar precusor mission, which has a delta v of 50-80 km/s, but that's with a very small spacecraft. Before, I didn't know that it used propellant, but it does (the magnetized particles that 'inflate' the magnetic field).

The reflectivity of the particles doesn't matter (it is an extremely tenous plasma with small opaque surface area). All they are for is making a magnetic field.

* Santarius, John F., and B. Grant Logan. ?Generic Magnetic Fusion Rocket Model.? Journal of Propulsion and Power 14.4 (1998):519-523

Just to a address a few random points:

A burning plasma was first achieved about 12 years ago, and this very much existent fusion technology (including mirrors) has only gotten better since then.

The first fusion power plant will be DT because it's easiest and practical; this will use steam turbines. D-3He plants, where the products are all charged particles, will use direct energy conversion technology where the efficienty is greater than 90%.

Fusion research in space makes no sense, since making a vacuum is the least of their problems, and constructing a reactor in space is impossible at this point.

With regards to the plasma sail technology, I don't how you, dicktice, came up with those advantages. No propellant is required.. yes, we might as well test it on the ISS (not much a solar wind in this neighborhood, but we could fire ions at it I guess). While were at it, it's insane for NASA not to test tethers on the ISS -- it could very practically be used to raise the orbit, since the panels give plenty of electricity, and we wouldn't have to waste rocket fuel for station keeping.

There is thrust falloff from the distance from the sun, since particle flux goes down the same way light flux does. No straight line astrogation, and as far as I understand it, no travel out of the ecliptic, since the force is only directed away from the sun.

No magnetic containment scenario for fusion will give you enough thrust, the power is too low (even if they press it to several GWs). High Isp, but not thrust. Magnetic rockets are for high Isp, and pulsed rockets are better for thrust (but can still have a very high Isp, ~10^5 seconds in efficient mode).

A pundit said that the shuttle program might not be grounded, at least, not as long as 2 years like what happened after Challenger, since this disaster happened not because of engineering flaws but probably because of the dangerous nature of reentry. Seems sort of reasonable to me.

So I don't predict a shakeup, especially since Prometheus is a technology program and Jupiter Tour isn't manned.

Sitting on my desk is a scientific research tile I made at Lockheed Martin in '01. The upgrade was being specifically designed to increase the impact strength of the tiles for things like ice and insulation hitting the tiles during liftoff. Funding stopped sometime after Sept. 11 2001 when the company switched to more military projects. Who knows.

There was just an interview on Fox News with the author of a book about the Chinese landing in America before the Europeans (in 1421). The book is apparenly big in Europe and is just about to be released here. He claims much evidence of Europeans running into Chinese explorers and assorted artifacts.

Those of you familiar with the ancient Chinese fleet that explored the world may have heard from various Mars bigwigs that some Chinese emperor destroyed the fleet on a whim, but in the interview he said that the fleet was taking up a huge amount of resources, like wood, and after the Chinese starting moving into Vietnam for more wood they started loosing a war there and such. Exploration got very unpopular and undoable so that's why they mothballed/destroyed the fleet. Can anyone add something to this history of the ancient Chinese fleet?

What do you mean by direct descendant?