New System Propels Satellites Without Propellants

cylonlover writes "Astronauts on the International Space Station (ISS) are testing a new propulsion system ... inside the station. While this might seem like the height of recklessness, this particular system doesn't use rockets or propellants. Developed in the University of Maryland's Space Power and Propulsion Laboratory, this new electromagnetic propulsion technology called the Resonant Inductive Near-field Generation System (RINGS) uses magnetic fields to move spacecraft as a way to increase service life and make satellite formation flying more practical."

Comments

MTBs

[nicholasjay]

So these work like magnetic torquer bars?

Re:MTBs

[Yoda222]

MTB generate only torque. Here they speak of propulsion system. But if I understand correctly the article, it's more about changing the relative position/attitude of two (or more) spacecraft than "real" propulsion of one spacecraft alone. It's a technology for formation flying

Re:MTBs

[Electricity Likes Me]

It can also work with planets though. Earth has a magnetic field, so by pumping current (or sinking it) you can increase and decrease orbital height relative to the planet.

Phew!

[pr0nbot]

"While this might seem like the height of recklessness, this particular system doesn't use rockets or propellants" ... just magnetic fields, so that's ok then, good think there's no electronic equipment up there or anything!

(I'm sure they know what they're doing, it's just that the summary seemed retarded.)

Re:Phew!

[bondsbw]

As an expert at Kerbal Space Program, I can say for sure that using such a system will result in crashing into the nearest moon. As does everything.

Re:Phew!

[gman003]

As a KSP player, I'm impressed that you manage to get all of your craft out of the atmosphere without destroying themselves. Hell, some of mine collapse on the launch pad.

Re:Phew!

[Nimey]

You want the EAS-4 strut connector; use it to tie each stage's parts together and they're much less likely to collapse.

I did up a mock-Saturn V and had to to a crisscross (top outer tanks to next-lower central tank) with struts on the second stage between the central stack and the top tanks on the four side stacks, because otherwise the four top-outer tanks tended to break off around 3-5km altitude, which completely broke the second stage.

Re:Phew!

[GNious]

Struts - they are what makes Space Flight possible!

Old news

[oodaloop]

This technology has been used in hoverboards since at least 2015.

Magsails?

[shawnhcorey]

Why don't they just use magsails?

Re:Magsails?

[interkin3tic]

The wiki article says those are merely proposed. This sounds closer to being a real thing. Why would they prefer a purely fictional technology?

Also, TFA mentions

According to an MIT study [PDF], when EMFF is perfected, it will have a wide number of applications including interferometers, space telescopes where each satellite carries a section of mirror, generating artificial gravity, creating a magnet shield against solar radiation storms, and clearing space debris by using their spin to toss the debris into a safer trajectory.

It sounds like this is useful for pushing stuff around in space at near distances, including non-autonomous propulsion such as junk, while magsails are (in theory) useful for moving only the cargo around over large distances, at slower accelerations.

Re:Magsails?

[shawnhcorey]

They're the same thing but a magsail has way more power. And all technology was nothing but an idea at one time.

Re:Magsails?

[OptimalCynic]

Or mainsails. 1500 kN, baby!

From the article

[Grantbridge]

"Electromagnetic formation flight (EMFF) gets around this propellant problem by turning the satellites in a formation into electromagnets. By using a combination of magnets and reaction wheels, spacecraft in formation can move and change their attitude and even spin without propellant. Satellites can change their polarity to attract or repel one another, turn, or shift their relative positions in any manner that doesn't require changing the center of gravity for the entire formation." So its all about formation flying, the satellites will pull/push off each other to remain in the correct formation. They will still needs propellent to move the whole cluster, but they can stay in formation without using any fuel.

Not as exciting as it sounds

[Karmashock]

Very cool technology but its not a reactionless drive sadly. The magnets merely allow a swarm of sats to hold a formation in relation to each other.

Oh well... darned laws of physics getting in the way again!

Re:Not as exciting as it sounds

[Urkki]

Very cool technology but its not a reactionless drive sadly. The magnets merely allow a swarm of sats to hold a formation in relation to each other.

Oh well... darned laws of physics getting in the way again!

Well, good thing it is not reactionless... I mean, if it were reactionless drive, then it would just move the Earth without moving the spacecraft, and what good would that be?

Cool, but not as awesome as the headline says

[vadim_t]

This is for positioning satellites relative to each other. The applications are things like telescopes made of several spacecraft to create a mirror larger than what is practical to launch in one piece.

But this isn't an engine that will allow a satellite to stay in orbit without fuel. They still need a traditional engine with propellant for everything besides adjusting the distance between nearby satellites.

Re:Cool, but not as awesome as the headline says

[ninjabus]

It's actually extremely awesome. Lets say a group of satellites is falling out of position. We could launch a single 'anchor' satellite loaded to the brim with propellant which would be able to effectively stabilize the rest of the constellation. That means the rest of the satellites can be launched with less propellant, making the system simpler and costs lower for everyone.

Re:Reliance on magnetic fields?

[Captain Hook]

Sounds like this is basically only useful to help maintain a low-power consumption orbit of heavenly bodies with strong magnetic fields(aka just earth in our solar system).

You are right, but there are currently about 6000 man made satellites in orbit (only about half of which are functional) and only 70 odd probes which go beyond earths magnetosphere so it's not like a huge number of vehicles couldn't use this technology. Especially since Satellite life times are normally limited by propellant they can carry

Also, just off the top of my head Jupiter and Saturn have magnetospheres.

Re:Reliance on magnetic fields?

[Yoda222]

From what I understand in the article, it's a technology for formation flying. You can generate your own magnetic field anywhere, using one of the spacecraft, and use this "non-natural" magnetic field from one of the other spacecrafts.

Re:Reliance on magnetic fields?

[nedlohs]

No, maybe you should try reading the article?

It has nothing to do with actual propulsion (despite the title) - just changing the relative positions of groups of satellites without changing the center of mass of the group. External (nonuniform) magnetic fields would cause problems (I suspect anyway) making the task more difficult and limiting just how far apart things can get while still using this system.

THat's nothing

[goombah99]

THis is just changing the orientation of subunits and spacing of subunits without changing the center of mass. It would not seem magical if theywere connected by gears. Here they are doing it with magnetic coupling. But there's no "propulsion" since that implies changing the center of mass.

the chinese have a method for massless propulsion however:

http://www.wired.com/dangerroom/2008/09/chinese-buildin/