Confusion about how the momentum is transferred

AI Thread Summary
The discussion centers on the feasibility of using non-pyrotechnic methods, such as a spring mechanism, to alter a satellite's velocity in space through momentum transfer. It explores the mechanics of a proposed system involving a spring-loaded mass that, when released, could theoretically reduce the satellite's speed. Participants note that while such a mechanism might create initial movement, conventional propulsion systems like rockets or compressed gas offer better thrust-to-mass ratios. The conversation also touches on the inter-satellite separation mechanism used by CanX 4/5, questioning whether the satellites would continue to drift apart after separation or remain stationary. Ultimately, the feasibility and practicality of the proposed ideas are challenged, emphasizing the need for more effective propulsion methods.
alditi
Messages
3
Reaction score
0
I'm thinking of non pyrotechnic ways to make changes in the velocity of a satellite in space and my concepts here might be totally wrong, but i wondered if transfer of momentum might work.
That is, as in the first image if i have a small mass compressed by a spring and i release it later by some mechanism so it springs away from the satellite, will i succeed in reducing the speed of the satellite? i know i might affect the moment of inertia of the satellite but what could the effects be if i have magnetotorquers to stabilize my satellite.
My professor dismissed it after ten seconds of listening to it and didn't explain why.

also, I read about the inter satellite separation mechanism the canX 4/5 used and i might not have understood the working fully but this is what i think they have done to separate the satellite.
They used an electrical debonding epoxy sold as ElectRelease to hold two plungers (one whose tip is a cone and the other whose tip is a cup. When current is passed the bond breaks and the belleville springs decompress and pull the plungers away from each other till it hits against the base plate shown by aluminum. you'll notice in the last picture of the second image there's a millimeter gap between the plunger and the aluminum base; this is the mechanism when it is loaded with the epoxy. when it gets debonded the springs expand and the plunger jumps back. the aluminum base is connected to the satellite face by the four screws and the belleville springs and the plates shown in red (called push plates) all sit inside the satellite(the link: https://tspace.library.utoronto.ca/bitstream/1807/31620/1/Urbanek_Jakub_201111_MASc_thesis.pdf it's explained properly here)
my question is, in this mechanism, are the satellites going to move away from each other with however small a relative velocity? (taking a ideal case neglecting effects of drifts) or will the satellites just separate and stay there?
 

Attachments

  • Untitledtemp.png
    Untitledtemp.png
    5.7 KB · Views: 542
  • ISS.jpg
    ISS.jpg
    19.3 KB · Views: 499
Physics news on Phys.org
will i succeed in reducing the speed of the satellite?
If you emit the ball in forward direction, yes. However, what is the advantage of this mechanical system? There are conventional systems which have a better thrust to mass ratio (rockets, or if the system should be really small just compressed gas), and if you have enough time an ion drive is even better.

If you separate two satellites with a "kick", they will continue to drift away. Their different orbits will change their relative movement within the timescale of the orbital period.
 
Thanks, you're right there are much more practical systems.
It's a small system and we were just discussing ideas. They wanted something original, something that hadn't been done before so i suggested this. and the prof made me feel the physics might be wrong.
In the ISS system i wasn't sure if this mechanism causes them to move away at all. the plunger is thrust inwards so i think if anything they should move towards each other...?
 
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
This has been discussed many times on PF, and will likely come up again, so the video might come handy. Previous threads: https://www.physicsforums.com/threads/is-a-treadmill-incline-just-a-marketing-gimmick.937725/ https://www.physicsforums.com/threads/work-done-running-on-an-inclined-treadmill.927825/ https://www.physicsforums.com/threads/how-do-we-calculate-the-energy-we-used-to-do-something.1052162/
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top