Scientist eyes 39-day voyage to Mars

Feb 26, 2010 by Jean-Louis Santini
A handout image from the US Geological Survey in 2008 shows a mosaic of the Schiaparelli hemisphere of the planet Mars projected into point perspective, a view similar to that which one would see from a spacecraft. A journey from Earth to Mars could soon take just 39 days, cutting current travel time nearly six times, according to a rocket scientist who has the ear of the US space agency.

A journey from Earth to Mars could in the future take just 39 days -- cutting current travel time nearly six times -- according to a rocket scientist who has the ear of the US space agency.

Franklin Chang-Diaz, a former astronaut and a physicist at the Massachusetts Institute of Technology (MIT), says reaching the Red Planet could be dramatically quicker using his high-tech VASIMR rocket, now on track for liftoff after decades of development.

The Variable Specific Impulse Magnetoplasma Rocket -- to give its full name -- is quick becoming a centerpiece of NASA's future strategy as it looks to private firms to help meet the astronomical costs of space exploration.

NASA, still reeling from a political decision to cancel its Constellation program that would have returned a human to the moon by the end of the decade, has called on firms to provide new technology to power rovers or even future manned missions.

Hopes are now pinned on firms like Chang-Diaz's Texas-based Ad Astra Rocket Company.

"In the early days... NASA support for the project was rather minimal because the agency did not emphasize advanced technologies as much as it's doing now," Chang-Diaz told AFP.

NASA was focused instead on the series of Apollo missions that delivered men to the moon for the first, and so far last, times.

"They were mesmerized by the Apollo days and lived in the Apollo era for 40 years, and they just forgot developing something new," he said.

Chang-Diaz, 60, hopes that "something" is a non-chemical rocket that eventually allow for a manned trip to Mars -- long the Holy Grail for Apollonians.

His rocket would use electricity to transform a fuel -- likely hydrogen, helium or deuterium -- into plasma gas that is heated to 51.8 million degrees Fahrenheit (11 million degrees Celsius). The plasma gas is then channeled into tailpipes using magnetic fields to propel the spacecraft.

That would send a shuttle hurtling toward the moon or Mars at ever faster speeds up to an estimated 35 miles (55 kilometers) per second until the engines are reversed.

Chang-Diaz, a veteran of seven space missions, said this rapid acceleration could allow for trips of just 39 days instead of the current anticipated round trip voyage to Mars that would last three years, including a forced stay of 18 months on the Red Planet, as astronauts await an opening to return to Earth.

The distance between the Earth and Mars varies between 35 and 250 million miles (55 million and 400 million kilometers) depending on their points of orbit.

And the use of ionized fuel could have the extra benefit of helping create a magnetic field around the spacecraft to protect against radiation.

Scaled-down models of the VASIMR craft have been built and tested in a vacuum, under a deal with NASA.

The next major step, according to Chang-Diaz, will be orbital deployment at the end of 2013 of a vessel using the 200-kilowatt prototype VASIMR engine, the VX-200.

Talks are underway with fellow space firms SpaceX and Orbital Science Corp to make that a reality.

Despite the hurdles ahead, Chang-Diaz sees the potential for a vast market for his technology -- maintaining and repairing fixing satellites or launching robotic and commercial missions to Mars.

His rocket may just launch NASA's brave new, commercial, world of space exploration.

Explore further: Two astronauts will expand envelope with one-year spaceflight

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Buyck
3.4 / 5 (5) Feb 26, 2010
The VASIMR engine in 39 days is a little bit old news. Russia is making a new generation of propulsion systems to. Nuclear spaceships en powerplants for on the Moon and Mars.

Link: http://nextbigfut...cts.html
Mayday
4 / 5 (4) Feb 26, 2010
I welcome this coming space race.
Our goal should be a permanent manned settlement on Mars with continually rotating crews by 2030.
I the meantime, we should use the Moon as a lab for testing robotic mining and construction techniques.
probes
1.7 / 5 (13) Feb 26, 2010
The VASIMR engine could actually get to Mars in 3.9 seconds, but the power would have to be higher than 200KW.
El_Nose
5 / 5 (6) Feb 26, 2010
@ probes

that would probably kill the astronaunts inside the craft as they are accelerated to 14,000,000 m / s in under 1 sec. they would be a puddle of goo.
barakn
4.3 / 5 (9) Feb 26, 2010
Nuclear power in space isn't exactly new, and Buyck has confused a propulsion system with a power plant. Even a VASIMR-equipped ship could use a nuclear power plant.
Yes
2.8 / 5 (6) Feb 26, 2010
I would never enter into a spaceship with only one of those VASIMR rockets. That is Russian roulette with a three round cylinder colt.
Maybe if it had three motors it would be a 27 round cylinder colt. LOL
El_Nose
4.2 / 5 (5) Feb 26, 2010
I guess I think we are setting our sights a little too high. Lets set up bigger space station first -- then get a stable moon base going -- and then a couple satellites that orbit the moon -- followed by a station on the dark side of the moon -- then and only then go for a Mars base.... And all the while we should be sending tons and tons of bacteria to Venus and Mars to start changing their atmospheres.

But we just finished the first space station -- lets keep building on that and moving forward - men on Mars while scientifically challenging and a game changer is like the failure of the Apollo missions -- yes we went to the moon a few times, but we never set up infrastructure to stay there. It is easier to fly away from a moon or space station than a planet. -- Fuel is a limiting factor
barakn
4.7 / 5 (10) Feb 26, 2010
Probes, you've just stated that VASIMR could take people to Mars faster than light speed. There's absolutely no way. Judging from your posting history, you've got some sort of mental hangup about VASIMR and a slippery concept of the amount of time it might take to get to Mars. I suggest seeking professional help.
NotAsleep
5 / 5 (3) Feb 26, 2010
@ probes

that would probably kill the astronaunts inside the craft as they are accelerated to 14,000,000 m / s in under 1 sec. they would be a puddle of goo.


I think Probes' point was that a pulsed nuclear rocket isn't that special and is, in fact, a fairly messy way to power a ship. Still, they'll probably end up using a nuclear reactor to power the VASIMR... I look forward to the orbital test!

Probes, looks like your favorite, the VASIMR, is getting closer to reality
rgw
5 / 5 (4) Feb 26, 2010
The VASIMR engine could actually get to Mars in 3.9 seconds, but the power would have to be higher than 200KW.

WHAT????????????????
Yes
4.6 / 5 (7) Feb 26, 2010
Probes might be right with his 3.9 seconds.
Apart from the fact that the astronaut would convert to goo cause of the acceleration.
It works like this.
If the rocket would go very fast, then time would dilate and space would contract for the astronaut. For the astronaut it takes 3.9 seconds to get to mars. For the observer on earth still a bit more than distance/c seconds.
yyz
5 / 5 (6) Feb 26, 2010
Well, we can send goo to Mars now. But Marvin the Martian is getting VERRRRRRRY ANGRY!
david_42
2.6 / 5 (5) Feb 26, 2010
A VASIMR engine modified for alpha particles combined with a WB-type reactor would be a natural.
eachus
2.7 / 5 (9) Feb 26, 2010
Everyone here is ignoring the elephant in room. Space elevators are coming, and that is what was so stupid about the Constellation program. We have the technology today to build a space elevator for the moon or Mars, and it would be small enough to package in a (large) spacecraft.

But why build the first operational skyhook on the moon or Mars? Uniform carbon nanotubes on the order of one inch long (3 cm) have now been constructed. For good spun nanotube fiber with cross-linking one to ten meter long nanotubes would be better, but the process can easily be scaled up to that point. Now all you need to do is fabricate a few hundred tons of such fibers, convert them into a cable (or tape) and get the cable into orbit.

Notice that shipping the cable in sections to the space station and deploying it from there is probably the best possible use of the space station. Do it right and the space station ends up as a depot 100 to 300 km up, and easily resupplied from the ground.
Yes
1.6 / 5 (7) Feb 26, 2010
SciFi dudes dream-on.
Put your feet firm on the ground.
Or are your feet hanging from your legs that hang from your corps to reach the ground?
eachus
4 / 5 (5) Feb 26, 2010
Sorry didn't relate space elevators to VASMIR. Once you have a space elevator from earth, it is (relatively) easy to launch cargoes to Mars from the far end of the elevator. Depending on length, this is enough to give any type of spacecraft a 15-20 miles per second sendoff. Such a mission would be likely to use VASMIR or some such to slow down before aerobraking at Mars. How do you get back? Think big. Take an elevator with you. (Much smaller for Mars.) You can use it to get up and down to the surface, then launch from the far end to return to earth.
EarthlingX
5 / 5 (3) Feb 26, 2010
Here is something to think about :
http://selenianbo...ing.html

VASIMR, oh, yes.
maunas
2 / 5 (4) Feb 26, 2010
Some how sooner or later we will do it if we remain enthuastic.
dachpyarvile
1.6 / 5 (8) Feb 26, 2010
His rocket may just launch NASA's brave new, commercial, world of space exploration.


And, yet, unless we have space stations or bases in space, we still will need a post-Apollo rocket booster technology to get it up into space in the first place.

We needed to get to a low-gravity or zero-gravity location in space from which to launch something like this. Obama is trying to kill such programs as the moon base. No one thus far has built a spacebase, either.

And VASIMIR to Mars in 3.9 seconds? Impossible. Even with current estimates for the VX-200 it still will need to include acceleration time and deceleration time. Calculations I have read in source material give approximately 6-7 days from LEO to LMO. That is to the Moon, much less Mars.

120,000,000 (distance at closest Mars encounter) / 186,000 (~c) = 645.1612903225806 (Seconds)

120,000,000 / 186,000
----------------------------- = 10.75268817204301 (min)
60

Even with light speed 3.9 seconds is impossible.
dachpyarvile
1.6 / 5 (7) Feb 26, 2010
39 days is believable. And, it still is a good thing because 39 days is a heck of a lot better than 6 months.

By the way, before someone chooses to attack my use of the term spacebase, consider that a spacebase, which we have never built, is somewhat of a different thing than something we have built--space stations.
dallas27
Feb 26, 2010
This comment has been removed by a moderator.
rgarbacz
2 / 5 (3) Feb 26, 2010
I guess I think we are setting our sights a little too high. Lets set up bigger space station first -- then get a stable moon base going ...


I would disagree. People are flying around the Earth for too long now. More than 40 years after landing on the Moon humankind is not even able to repeat this achievement. I see the benefits of 'small steps', but I am afraid that this attitude will keep us with the chemical propulsion for many decades to come. I hope that VASIMR will find its use in deep space probes, and orbital haul robots. I also hope that the nuclear reactors will find its way to space. Without these steps we will keep dreaming about the space era.
NotAsleep
5 / 5 (2) Feb 26, 2010
Some awesome info on the VASIMR, including a few videos of the latest prototype:

http://www.adastr...c/VASIMR

Note that this info comes direct from the company that builds it so probably a little biased
macrumpton
5 / 5 (4) Feb 26, 2010
Nasa's biggest success in the last decade has been the Mars rovers, that have worked far better and longer for less money than even the biggest fan predicted. Until we have the tech (developed on space stations) to have an independent colony, I think we should forget about manned missions to other planets. Telepresence gives us 80% of the benefit for a tiny fraction of the cost and risk.
PPihkala
4 / 5 (4) Feb 26, 2010
Hasn't anybody noticed the temperature conversion miscalculation? 51.8 million degrees of F can not be equivalent to 11 million degrees of C. The formula to get C from F is C = (F-32)*5/9. At millions of degrees this can be simplified to C = F * 5/9 = F / 1.8. So 51.8 divided by 1.8 makes 28.8, not 11.
PinkElephant
5 / 5 (6) Feb 26, 2010
@dachpyarvile,
We needed to get to a low-gravity or zero-gravity location in space from which to launch something like this. Obama is trying to kill such programs as the moon base.
Blame Congress, not Obama. The Constellation has been chronically and irreparably underfunded since the start. It was never a serious effort; political posturing is all it ever was.

You're quite right, in that we need to get into LEO. The crucial part you're missing, is COST. What NASA ought to be focusing on, is reducing cost of launch to orbit. They had this priority in the late 90's, but Bush scrapped the efforts.

If we could bring down the costs of launch from $10,000/lb to $100/lb, then all sorts of things become possible: from space bases, to moon bases, to Mars bases. Until then, all these dreams are just multi-trillion-dollar, unrealistic/unfundable fantasies.
dachpyarvile
1 / 5 (9) Feb 26, 2010
We are nowhere near--technologically speaking-- to reducing cost that much. Would that we were. We have a way to go before even getting near that. Congress may share the blame but Obama's death panel is working to nix all moon plans. There are members of Congress who are aiming for a fight but it is likely that his position will win and going to the Moon will become nothing but a pipe-dream.
PinkElephant
4.8 / 5 (5) Feb 27, 2010
We are nowhere near--technologically speaking-- to reducing cost that much.
Which is why this ought to be the #1 priority for R&D. Anything else is just wasteful spending.
it is likely that his position will win and going to the Moon will become nothing but a pipe-dream.
It is, and always has been, nothing but a pipe-dream. There's no money to fund it or sustain it, never has been, and never will be. Our nation is bankrupt enough as it is.

The only way a manned Moon program (never mind manned Mars programs) can ever be anything other than a ridiculously wasteful PR campaign, is if we find a way to reduce launch costs by a couple orders of magnitude. Then, and only then, could a Moon base be constructed, maintained, expanded, and sustained indefinitely without breaking the bank.
Parsec
4.7 / 5 (3) Feb 27, 2010
We are nowhere near--technologically speaking-- to reducing cost that much. Would that we were. We have a way to go before even getting near that. Congress may share the blame but Obama's death panel is working to nix all moon plans. There are members of Congress who are aiming for a fight but it is likely that his position will win and going to the Moon will become nothing but a pipe-dream.


Its hard to justify massive spending on putting men on the moon in our current economic climate. It saddens me a lot, but its political suicide to pursue it now.
Parsec
5 / 5 (4) Feb 27, 2010
We don't have the technology to reduce costs to LEO from the current $10k/lb to $100/lb, but even $1-2k/lb would be a total game changer. This could be achieved using current technology and better engineering.

I do agree with the poster above about the economics of the space elevator, but we need to reduce the cost of achieving LEO to less than $1k/lb before even thinking about trying to do that. But at $1k/lb, it would be cost effective to launch solar power satellites, a much larger permanent human presence in LEO, and moon bases. I believe that reducing the LEO cost right now should be the overwhelming priority. I think this is also the goal of Obama via his support of the private space program.
Hungry4info2
3.7 / 5 (3) Feb 27, 2010
Even with light speed 3.9 seconds is impossible.


I was wondering who would point that out, lol.
As you can tell, people don't put a lot of thought into what they write.
YawningDog
Feb 28, 2010
This comment has been removed by a moderator.
rwinners
5 / 5 (2) Feb 28, 2010
While all you are working out the details, how about attaching one of those plasma engines to the space station and using it to maintain a consistent orbit. Good test and good effect as well.
And when the station becomes obsolete, leave that engine on until the station reaches geosyncronous orbit.
zbarlici
1.7 / 5 (3) Feb 28, 2010
a working bussard fusion reactor would kick ass coupled with a VASIMR.
zbarlici
1.7 / 5 (3) Feb 28, 2010
actually, come to think of it, a working BFR would make for one super-cheap(no fuel costs)kick-ass Earth to LEO propulsion system. It is in the works at Los Alamos, paid for by the Navy. We will know within one year now(not sure what the contract deadline is) whether the concept works. check out talk-polywell.org
Sonhouse
5 / 5 (2) Feb 28, 2010
The VASIMR engine could actually get to Mars in 3.9 seconds, but the power would have to be higher than 200KW.


Wow, so it would be going about 50 times the speed of light! What a revelation! I want one....
Adam
5 / 5 (2) Feb 28, 2010
If anyone bothered reading the literature they'd notice that 39 days to Mars needs a 200 megawatt nuclear reactor light enough for the job. Chang-Diaz proposes using a gas-core reactor with an MHD generator operating in a close-cycle i.e. working fluid flows around in a loop. It's a nice design, but currently such a reactor is getting precisely zero funding from NASA or anyone else. Ain't gonna happen without the power people!
KB6
3.5 / 5 (4) Feb 28, 2010
Like I said in another post: Take all the billions we spend on human space exploration and turn it to the advancement of truly transformative technologies. I mean things like nanotech, artificial general intelligence, neuroscience and neural augmentation, etc. Advancing those will change everything else, including ourselves. Then finally we - and our machine peers - will be ready for space.
Sanescience
2.3 / 5 (6) Mar 01, 2010
On Space Elevators: DUMB IDEA!!! Massively expensive, little understood earth-magnetic-atmosphere dynamics, little understood materials aging and hard radiation effects, no thought on how to decommission safely, and exquisitely fragile to space debris that it CAN'T DODGE PEOPLE! Plus when the thing does crash down to the ground, it will cut a path of destruction all the way around the equator of the earth.
Sanescience
3 / 5 (4) Mar 01, 2010
I find the best ides are to develop advanced robotic remote-presence for use on the moon that can share costs with the military for remote battlefield presence technologies. And to reduce costs / improve reliability of getting into space, which I suspect SpaceX is currently doing the best job of.
rbrtwjohnson
2.6 / 5 (5) Mar 01, 2010
A 200MW VASIMR plasma rocket will require a nuclear power plant on-board, I think an aneutronic reactor, using He3-He3 or p-B11, could generate electricity efficiently without neutron emission, preventing it from causing injury to astronauts.
http://www.youtub...FowOge_M
http://www.crossf...iew.html
ksupak
5 / 5 (1) Mar 01, 2010
I think the VASIMR engine is a step in the right direction for space propulsion. However there are some fundamental problems with using the VASMIR engine aboard the ISS and for a 39 day Mar's mission.

The ISS generates a maximum of 260 kWe. Assuming that half of this power is used for life support, computers, etc, then that leaves 130 kW for the VASIMR.

It would take between 10-20 MWe to have a 39 day Mars mission. How do you generate this power in current or future space power technology. The first and only space nuclear reactor to orbit the earth (SNAP-10a) was designed to produce 30 kW of power and had 88 ft2 of radiator area. Paper designs for advanced reactors were between 100 and 300 kW. That means they would need around 35 advanced space nuclear reactors(300 kW ea) for a 10 MWe VASIMR and around 30,000 ft2 of radiator. This doesn't include pump power or life support power. I would like to see it built...but definitely have be done on orbit.
PinkElephant
5 / 5 (5) Mar 01, 2010
@rwinners,
While all you are working out the details, how about attaching one of those plasma engines to the space station and using it to maintain a consistent orbit. Good test and good effect as well.
You're a bit behind the curve, buddy ;)

http://www.physor...552.html

Quoting:
The company has signed an agreement with NASA to test a 200-kilowatt VASIMR engine on the International Space Station (ISS) in 2013. The engine could provide periodic boosts to the ISS, which gradually drops in altitude due to atmospheric drag. ISS boosts are currently provided by spacecraft with conventional thrusters, which consume about 7.5 tonnes of propellant per year. By cutting this amount down to 0.3 tonnes, Chang-Diaz estimates that VASIMR could save NASA millions of dollars per year.

PinkElephant
5 / 5 (4) Mar 01, 2010
@Adam,

From the same article:

http://www.physor...552.html

But Ad Astra has bigger plans for VASIMR, such as high-speed missions to Mars. A 10- to 20-megawatt VASIMR engine could propel human missions to Mars in just 39 days, whereas conventional rockets would take six months or more.


Note the mention of 10-20 MW. You said 200 MW. You're off by a factor of 10.
probes
1.7 / 5 (3) Mar 03, 2010
even with a 20-megawatt reactor and 1000 sq.ft of radiators, the distance at closest Mars encounter (120,000,000) / 186,000 (~c) = 645.1612903225806 (Seconds)

120,000,000 / 186,000
----------------------------- = 10.75268817204301 (min)
60

So, we would need at least 186,000 sq.ft of radiators. Impossible!
otto1923
3 / 5 (1) Mar 03, 2010
The VASIMR engine could actually get to Mars in 3.9 seconds, but the power would have to be higher than 200KW.
Well thats pretty damn fast i tell you what eh?
otto1923
3 / 5 (1) Mar 03, 2010
On Space Elevators: DUMB IDEA!!! Massively expensive, little understood earth-magnetic-atmosphere dynamics, little understood materials aging and hard radiation effects, no thought on how to decommission safely, and exquisitely fragile to space debris that it CAN'T DODGE PEOPLE! Plus when the thing does crash down to the ground, it will cut a path of destruction all the way around the equator of the earth.
Technological details which can and will be worked out in progressive iterations, providing invaluable advances in materials science and engineering. If the basic concept is sound and competitive then it will happen. What is this- we cant, it wont, thats impossible attitude? You union or something?
probes
1.5 / 5 (2) Mar 03, 2010
A trip to the moon in less time than it takes to eat a burger? That is insane! That must be why NASA is not working on these engines. Its just mad?
Husky
5 / 5 (1) Mar 06, 2010
An attractive long term goal would be a network of interconnecting nuclear power stations throughout the solar system providing beamed energy all the way to pluto, no radiator/weight problem as it can be dealt with by the remote reactors, getting their ice/water coolant from local moon/asteroid sources...

Once the network is in place, using the old fashioned way in say 30 years, you could realistically speak about trip times of 20-30 days to the next planet and every now and then send some uranium to refuel the reactors.
siliconboy
4.5 / 5 (2) Mar 07, 2010
Lads, AI is the way to go, are future grand kids will do this.

If you think about space, it was built for the stuff. Solar power from stars, while running your quantum procs in the planet shadows at -2.7K. intelligence that can beam itself at light speed from earth to orbit and beyond, and upon arrival at a planet can build machinery at a nano level form raw elements, no payload necessary. A giant, interconnected brain spanning galaxies increasing computation power at the speed of light, but more importantly, able to imagine more and more things. like 'crossing' into other dimensions/universes. or downloading itself into human or animal body's on earth to hang out with friends, to experience life as we do. to think, touch and feel the immedcacy of life, even as its hive mind is aware of everything that has happened (complete assimilation of internet/human culture histroy) and aware of everything always.
KB6
2.5 / 5 (2) Mar 08, 2010
@siliconboy
I agree. Every increase in our machine's sophistication and intelligence makes human space exploration more and more pointless. But I can see how we may wish to modify ourselves to keep up with our machines and join them in space some day: In the really long run, Earth is a death trap for us.
dachpyarvile
1.5 / 5 (6) Mar 11, 2010
A trip to the moon in less time than it takes to eat a burger? That is insane! That must be why NASA is not working on these engines. Its just mad?


Umm...no. It would be 6-7 days for a 200-kW VASIMIR, which includes acceleration and deceleration times.

In addition, you will never break light speed with a VASIMIR, no matter how large the radiator. And, I nowhere said that it would require 186,000 sq. ft. of radiator. The 186,000 figure I gave above is roughly the speed of light.

The point I made is that even at light speed (not happening with a VASIMIR of any size) a ship could not reach mars in your claimed 3.9 seconds. Even at light speed, the trip would take at least 10.75268817204301 minutes (or, 645.1612903225806 seconds) one way at closest Mars encounter.

VASIMIR is NOT a FTL technology. The best one could do is to approximate light speed and even that claim would be pushing things.

Still, 39 days for a larger VASIMIR would be cool enough for now.
beppdude
5 / 5 (1) Mar 15, 2010
@dachpyarvile

I like your calculations that round off the speed of light to the nearest thousand m/s yet yield results accurate to .000000000001 seconds
dachpyarvile
1 / 5 (5) Mar 15, 2010
"186,000 miles per second" is the most common usage so I went with that. Can I help what the calculations did with what I used? You are welcome to verify them with a calculator, if you wish.

Want more precision in miles per second? Ok. Here:

120,000,000 / 186282.3970512209
--------------------------------------------------- = 10.73638750445149 (minutes)
60

That is 644.1832502670897 seconds for light to travel to Mars at encounter. Better? Doesn't make much difference in the long run, though.

There still is no way any VASIMIR will get anyone to Mars in 3.9 seconds.
dachpyarvile
1 / 5 (5) Mar 15, 2010
For those metrically inclined, the current speed of light is defined as 299,792,458 meters per second.

http://www.bipm.o...8_en.pdf

See page 112 (page 20 in the PDF) of the above document.

299,792,458 meters/second = 186,282.3970512209 miles/second.

But, if you want me to get more units of precision, here is a more precise calculation of minutes for an object traveling at the speed of light to reach Mars at encounter:

10.736387504451494519223093550704
dachpyarvile
1 / 5 (5) Mar 15, 2010
One could go further in precision for the speed of light in miles per second.

299,792,458 (meters/s) / 1,609.344 (meters in a mile) = 186,282.3970512208701185079137835 miles/s

One could get even more precise but what would be the point overall when discussing things like this in a public forum? Really? :)
beppdude
5 / 5 (2) Mar 15, 2010
Someone didn't take physical science in 8th grade....

this should get you up to speed

http://www.chem.s...dex.html
beppdude
not rated yet Mar 15, 2010
ps. that 3.9 second guy was just trying to be an idiot why are you guys taking him seriously?
dachpyarvile
1 / 5 (6) Mar 15, 2010
Someone didn't take physical science in 8th grade....

this should get you up to speed

http://www.chem.s...dex.html


You are kidding, right? It is not like I am writing a scientific paper requiring greater precision to get the main thrust of a point across. When I went to school (probably before you were born) Physical Science was a requirement both in the Middle School and High School systems in order to graduate.

(Does this date me? One of my old textbooks in High School was on the subject Latin).

Even in the textbooks of the day the numbers for the speed of light were given imprecisely for a general audience. Nonetheless, perhaps I am giving you too much credit by replying at all... :)

As to paying attention to "probes," it is more for the benefit of those who may be misled by his inanity that I posted what I did. Wherever he is getting his material obviously is a crank source.
beppdude
5 / 5 (1) Mar 15, 2010
You don't get what I'm trying to say at all...

When you did your calculation you used 186,000 mi/sec and got an asnwer of "645.1612903225806" seconds anything beyond the 645 has no physical meaning whatsoever because you estimated the speed of light to only three sig figs. I wouldn't normally call someone out for it but it just looked so rediculous that I had to say something.

I was just joking with my first post because I figured that you just copy and pasted your answers from the calculator and expected you to just respond with a "haha" or an "lol", I wasn't trying to be a dick or anything so sorry if I offended you.

Good point with the probes issue though, some people might not know that he was just trying to get a rise out of people and might have taken him seriously.
dachpyarvile
1 / 5 (5) Mar 15, 2010
No, I got fully what you were saying after the remark to which I took offense. It was the way that you said it that irritated me a bit. Sorry for the reaction and thanks for the apology.

You are right that I should have rounded. Such numbers are meaningless to the public. So, here is my revised figuring for the general public, rounded to the nearest tenth.

~120,000,000 / ~186,282.4
------------------------------------------- = ~10.7 (minutes)
60

Or, 644.2 seconds.

Still doesn't change the initial point, however, as I hope you would acknowledge. :)
Yes
not rated yet Mar 15, 2010
One little obstacle and back to reality. Feet on the ground and not in space.
This VASIMR rocket has one newton of thrust per 100 kilowatt. So this 200 kilowatt version has two newton of thrust. If they put three of these motors to a spaceship it has about 1 pound of thrust.
A normal space shuttle rocket has the thrust of about 400000 pounds during 6 minutes.
Imagine the ship weighs 1000 kg. This is just an example of
While a=F/m, a is about 2e6/1e3 is about 2000 m/s2
While the gained speed is V=Vo+at, the ship will gain 2000m/s speed every second during 360 seconds.
While VASIMR will have an a is about 5/1e3 is 5mm/s2
The advantage of VASIMR is that it will work 86400 seconds per day, so that means that in order to burn one equivalent spaceshuttle fuel tank it must work during many days and need very tiny amounts of actual fuel. So the advantage is that you do not need to bring so much fuel into space.
High acceleration values are not the goal. Uninterrupted functionality is the goal
probes
1 / 5 (1) Mar 18, 2010
So you are saying that the VASIMR should function for less than 3.9 seconds?
dachpyarvile
1 / 5 (4) Mar 19, 2010
So you are saying that the VASIMR should function for less than 3.9 seconds?


Nope. VASIMIR cannot do what you think it can.

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