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Lt. Commander
Join Date: Dec 2007
Posts: 120
# 11
05-30-2012, 02:19 PM
Found out why this is not begin used on ISS, apparently the ISS power is not strong enough, its need to be 200kw. There is always something isn't there.
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 12
05-30-2012, 06:25 PM
Quote:
Originally Posted by RAJ_2011
I have read that page several times it does not mention about it being delayed to 2014, can you tell where it says it?

I thought they were going to put the VF-200 on the ISS last year or this year. I have seen documentaries on the Discovery channels that say they have been making this since 2003, why the long wait if it works!?

According to this clip, http://www.adastrarocket.com/aarc/VASIMR , they were planning to have the VF-200 on the ISS, does anyone know if they have done this? I have searched and nothing is mentioned on the web.
Testing on the space station
On December 8, 2008, Ad Astra Company signed an agreement with NASA to arrange the placement and testing of a flight version of the VASIMR, the VF-200, on the International Space Station (ISS).[17] As of February 2011, its launch is anticipated to be in 2014,[18][19] though it may be later.[7] The Taurus II has been reported as the "top contender" for the launch vehicle.[18] Since the available power from the ISS is less than 200 kW, the ISS VASIMR will include a trickle-charged battery system allowing for 15 min pulses of thrust.

That is the section from that wiki where it says the launch is anticipated for 2014 although it may be later. Kinda pointless since you found something saying it won't be tested on the station after all because of power concerns.
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 13
05-30-2012, 06:32 PM
Quote:
Originally Posted by RAJ_2011
Well apparently they have experimenting with plasma engine since the beginning of the space race its just now it is more efficient and faster i think. What happened to the Deep Space 1 ion engine? isn't that just as good as the Vasimr engine, maybe they could use both at the same time.
The Deep Space 1 Ion engine is no longer being developed. It was tested successfully, but there where several aspects that were discovered after testing that could be redesigned to give greater efficiency ratings. Last I had looked into it they were getting ready to do preliminary tests on a Gen 3 Ion Engine.

progression of Ion Engine:

DS1 Ground tested

DS1 Successful Space Testing and performance

DS1 design and space test performance data used to create Gen 2 Ion engine

Gen 2 Ion engine Ground tested

Gen 2 ground based performance results and redesigns used to further overall design for Gen 3

Gen 3 Ion Engine design and development
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 14
05-31-2012, 02:44 AM
What I don't get is what is the difference between the Ion engine and Vasimr engine in terms of speed and efficiency, I have looked on the web but nothing shows which is the nest to use. Could someone shed some light on this please.

The next probe of ship they build they should use both the Vasimr engines and Ion engines? Or do they do the basically the same thing.

Apparently Chandiz mentioned about a 200,000 kw power source, what types of nuclear rectors could be used.
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 15
05-31-2012, 03:16 AM
They're both ion engines, just two different designs and operating principles.

The Standard Gen/ Next-Gen ion engines are designed for lower longer burns achieving faster speeds at lower acceleration. uses electrodes and multiple moving parts and needs more maintenance. A potentially huge benefit is a standard ion engine produces an electrical charge as a byproduct that could be harnessed and feed into the power system.

The Vasimr Ion engine uses electromagnetic field instead of electrodes, has very few and smaller moving parts that require less maintenance. The Vasimr engine also provides a larger thrust over a short amount of time, however in doing so in produces a huge amount of heat that needs to be properly dissipated. The strong electromagnetic fields needed for the engines also produces hazardous dangers for electronic devices on board and requires a much greater amount of energy.
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 16
05-31-2012, 03:32 AM
Quote:
Originally Posted by voicesinthedark View Post
They're both ion engines, just two different designs and operating principles.

The Standard Gen/ Next-Gen ion engines are designed for lower longer burns achieving faster speeds at lower acceleration. uses electrodes and multiple moving parts and needs more maintenance. A potentially huge benefit is a standard ion engine produces an electrical charge as a byproduct that could be harnessed and feed into the power system.

The Vasimr Ion engine uses electromagnetic field instead of electrodes, has very few and smaller moving parts that require less maintenance. The Vasimr engine also provides a larger thrust over a short amount of time, however in doing so in produces a huge amount of heat that needs to be properly dissipated. The strong electromagnetic fields needed for the engines also produces hazardous dangers for electronic devices on board and requires a much greater amount of energy.
Fascinating, I watched on the discovery science channel should something about a ramjet engine which scoops up hydrogen as it travels much like how a jet engine works when scooping up air. Do yo know of there has been an advances in this?
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 17
05-31-2012, 11:18 PM
Quote:
Originally Posted by RAJ_2011
What I don't get is what is the difference between the Ion engine and Vasimr engine in terms of speed and efficiency, I have looked on the web but nothing shows which is the nest to use. Could someone shed some light on this please.

The next probe of ship they build they should use both the Vasimr engines and Ion engines? Or do they do the basically the same thing.
The big advantage of VASIMR (besides, as others have posted, the fewer moving parts and lack of erosion of the ion grate used by ion engines) is that VASIMR is like a continuously-variable transmission on an automobile. Basically, for any given energy input, you can dump any amount of propellant that you want into the system. If you use only a small amount of propellant, then you get very high efficiency (and thus more total impulse per unit of propellant) but much lower thrust (and thus slower acceleration). But if you use more propellant, then you get more acceleration but less efficiency. This means that you can use a high-thrust low-efficiency setting for achieving planetary escape velocity, and then a low-thrust high-efficiency setting for cruising. Please take note that even the highest-thrust settings proposed still could not lift the spacecraft's own mass from the surface of Earth--even with a nuclear fusion reactor powering it, the cooling equipment to keep it from melting would be too heavy.

Plain old electrostatic ion engines, on the other hand, do not have this continuously-variable attribute, and instead are locked into a single power/thrust ratio. If you want more thrust, you need more power as well as more propellant. Erosion of the ion grid (from being bombarded with the ions all the time) also places an upper limit on thrust per emmitter, which means that if you want thrust high enough for interplanetary manned missions, you need a freaking huge array of them--enough that bulk and mass become a concern. As such, ion engines are best suited for slooooow unmanned missions where limited propellant supply is the main barrier rather than travel time--for example, the Dawn probe that is currently orbiting the asteroid Vesta and which in a few months will depart for Ceres--the ion engines are what make it possible to visit two large asteroids with a realistic amount of propellant.

That said, VASIMR is probably the best that we will be able to do until we can use fusion plasma for propulsion.
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 18
05-31-2012, 11:25 PM
Quote:
Originally Posted by RAJ_2011
Fascinating, I watched on the discovery science channel should something about a ramjet engine which scoops up hydrogen as it travels much like how a jet engine works when scooping up air. Do yo know of there has been an advances in this?
The Bussard Ramjet concept is mainly meant as an interstellar sublight propulsion concept. One of the issues with it is that it can only scoop enough hydrogen in the interstellar medium to sustain itself once it is already going at a couple percent of the speed of light (i.e. faster than anything we can currently build). However, once the ramjet kicks in, it should be able to take you arbitrarily close to the speed of light (limited only by how much acceleration you can produce and how much acceleration your ship and crew can tolerate).
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 19
06-01-2012, 11:03 AM
Quote:
Originally Posted by ChibiClari View Post
The Bussard Ramjet concept is mainly meant as an interstellar sublight propulsion concept. One of the issues with it is that it can only scoop enough hydrogen in the interstellar medium to sustain itself once it is already going at a couple percent of the speed of light (i.e. faster than anything we can currently build). However, once the ramjet kicks in, it should be able to take you arbitrarily close to the speed of light (limited only by how much acceleration you can produce and how much acceleration your ship and crew can tolerate).
Interesting.



Does anyone know why it has been delayed to 2014??
Lt. Commander
Join Date: Dec 2007
Posts: 120
# 20
06-01-2012, 04:51 PM
Never mind I remember why it was pushed back, its because of the power issues with the ISS. Anyway let me get this straight with the Ion thruster is has higher thrust output but a lower thrust to start out with but with Vasimr its is the other way round? Also out of the 2 which is the faster? I have looked on Wikipedia and it does not give an exact speed of each propulsion.
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