4 ms·

So, just to be clear (because I don't see it mentioned anywhere). Are we taking about the EMDrive here?

by cduguet 9y ago

binarycoffee 9y ago
This is a customized Hall thruster. Disclosure: I was involved in that project.
- ccozan 9y ago
  Do you know, is related to this study? [0] [0] http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2011index/IEPC-2011-142.pdf http://erps.spacegrant.org/uploads/images/images/iepc_articl...
  - binarycoffee 9y ago
    Yes, this is related (not the author of the cited article but I know him well). There were also several precursor experimental studies funded by ESA, one of which [1] can be found in the same conf. proceeding. [1] http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2011index/IEPC-2011-224.pdf http://erps.spacegrant.org/uploads/images/images/iepc_articl...
deleted 9y ago
[deleted]
0xCMP 9y ago
Doesn't look like it. This type of drive has been around, but the issue had been that it would run out of propellant that powered it to keep the satellite in low earth orbit. This is the successful testing of a drive of the same type, but it collects that material from the atmosphere so it hopefully it won't run out for a long time and keep missions running longer.
calcifer 9y ago
From a cursory reading, it doesn't sound anything like that at all. https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster
foota 9y ago
Don't think so. Sounds like it accelerates air particles using electricity.
martythemaniak 9y ago
No. This is a ion thruster, a class of thrusters which already exist and are used in various satellites. They carry a propellant (xenon), then use electricity to accelerate and shoot the propellant out the back. This provides extremely efficient, but low amount of thrust (like a nudge). This development gets rid of the need to carry propellant. They satellite will scoop it up from the atmosphere, saving weight and prolonging life.
- flukus 9y ago
  So "air collecting" or "mass collecting" would be more accurate since it doesn't really breath like a typical air breathing engine?
  - andrewwharton 9y ago
    It doesn't accelerate the air like a typical air breathing engine, but it certainly ingests the air like one. It's basically a ramjet but uses electric charge to accelerate the exhaust gas rather than hydrocarbons.
deleted 9y ago
[deleted]
fsloth 9y ago
ELY 5: No, this is actual Newtonian physics. Rockets function based on Newton's third law: every reaction creates an equal and opposite reaction. We sit on wheeled office chairs, I push you- we both move, to opposite directions. Rockets aren't fueled by office chairs, though, but by gases. They push the gas molecules into a particular direction and themselves are pushed into another. So, to move in space by pushing stuff, you need two things: a) mass to push away b) some power to do the pushing (This ignores several categories of other forms of force generation on space craft like solar sails). Chemical fuel rockets happen to strike two flys on one go - the mass they carry also generate the energy for the push, so that's only a matter of plumbing and hydrodynamics to get them going. The problem with this approach, though, is that once you run out of fuel, you run out of fuel. No more chairs, no more acceleration. Refueling in space is really expensive, if you need to bring up the propellant from a deep gravity well like earths surface to the orbit (https://xkcd.com/681/ https://xkcd.com/681/). There is no necessity the propellant (i.e the 'chairs') needs to generate the energy for pushing itself away. You can you Some Other Physics to push the propellant away from the vehicle. It works just as fine. This system collects the fuel from sparse gas surrounding it, and expels it using an electric thruster, which probably get's it's energy from solar panels. Potentially, like some other poster noted, you could design a spacecraft with this that once it reaches planetary orbit, it can hop from planet to planet and refuel itself indefinetly (just as long as the planets have an atmosphere). So it's Way Cool, and this has been hypothesized in science fiction for decades, so it's also Genuine Scifi Space Tech :)
Symmetry 9y ago
They just throw stuff out the back of the rocket really fast to move forward, like any other sort of rocket. The nice thing about electrical rockets is that they decouple the energy used to throw the propellant from the chemical energy generated from burning the fuel, so you can end up throwing it out fast for very efficient rockets if you have enough electricity. http://hopefullyintersting.blogspot.com/2015/03/rockets-electric-propulsion.html http://hopefullyintersting.blogspot.com/2015/03/rockets-elec...

So, just to be clear (because I don't see it mentioned anywhere). Are we taking about the EMDrive here?

binarycoffee 9y ago

This is a customized Hall thruster. Disclosure: I was involved in that project.

ccozan 9y ago
Do you know, is related to this study? [0] [0] http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2011index/IEPC-2011-142.pdf http://erps.spacegrant.org/uploads/images/images/iepc_articl...
- binarycoffee 9y ago
  Yes, this is related (not the author of the cited article but I know him well). There were also several precursor experimental studies funded by ESA, one of which [1] can be found in the same conf. proceeding. [1] http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2011index/IEPC-2011-224.pdf http://erps.spacegrant.org/uploads/images/images/iepc_articl...

deleted 9y ago

[deleted]

0xCMP 9y ago

Doesn't look like it. This type of drive has been around, but the issue had been that it would run out of propellant that powered it to keep the satellite in low earth orbit. This is the successful testing of a drive of the same type, but it collects that material from the atmosphere so it hopefully it won't run out for a long time and keep missions running longer.

calcifer 9y ago

From a cursory reading, it doesn't sound anything like that at all. https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster

foota 9y ago

Don't think so. Sounds like it accelerates air particles using electricity.

martythemaniak 9y ago

No. This is a ion thruster, a class of thrusters which already exist and are used in various satellites. They carry a propellant (xenon), then use electricity to accelerate and shoot the propellant out the back. This provides extremely efficient, but low amount of thrust (like a nudge). This development gets rid of the need to carry propellant. They satellite will scoop it up from the atmosphere, saving weight and prolonging life.

flukus 9y ago
So "air collecting" or "mass collecting" would be more accurate since it doesn't really breath like a typical air breathing engine?
- andrewwharton 9y ago
  It doesn't accelerate the air like a typical air breathing engine, but it certainly ingests the air like one. It's basically a ramjet but uses electric charge to accelerate the exhaust gas rather than hydrocarbons.

deleted 9y ago

[deleted]

fsloth 9y ago

ELY 5: No, this is actual Newtonian physics. Rockets function based on Newton's third law: every reaction creates an equal and opposite reaction. We sit on wheeled office chairs, I push you- we both move, to opposite directions. Rockets aren't fueled by office chairs, though, but by gases. They push the gas molecules into a particular direction and themselves are pushed into another. So, to move in space by pushing stuff, you need two things: a) mass to push away b) some power to do the pushing (This ignores several categories of other forms of force generation on space craft like solar sails). Chemical fuel rockets happen to strike two flys on one go - the mass they carry also generate the energy for the push, so that's only a matter of plumbing and hydrodynamics to get them going. The problem with this approach, though, is that once you run out of fuel, you run out of fuel. No more chairs, no more acceleration. Refueling in space is really expensive, if you need to bring up the propellant from a deep gravity well like earths surface to the orbit (https://xkcd.com/681/ https://xkcd.com/681/). There is no necessity the propellant (i.e the 'chairs') needs to generate the energy for pushing itself away. You can you Some Other Physics to push the propellant away from the vehicle. It works just as fine. This system collects the fuel from sparse gas surrounding it, and expels it using an electric thruster, which probably get's it's energy from solar panels. Potentially, like some other poster noted, you could design a spacecraft with this that once it reaches planetary orbit, it can hop from planet to planet and refuel itself indefinetly (just as long as the planets have an atmosphere). So it's Way Cool, and this has been hypothesized in science fiction for decades, so it's also Genuine Scifi Space Tech :)

Symmetry 9y ago

They just throw stuff out the back of the rocket really fast to move forward, like any other sort of rocket. The nice thing about electrical rockets is that they decouple the energy used to throw the propellant from the chemical energy generated from burning the fuel, so you can end up throwing it out fast for very efficient rockets if you have enough electricity. http://hopefullyintersting.blogspot.com/2015/03/rockets-electric-propulsion.html http://hopefullyintersting.blogspot.com/2015/03/rockets-elec...