What's the physics behind the Fotino tether

[askold]

The delivery module is swung like a pendulum which sends it on its way to Earth.<br /><br />Basically, it's a way to impart the proper amount of delta V to knock it out of orbit.<br /><br />How does this compare against pushing the module out with a small rocket or a big spring? 20 miles of tether has to be pretty heavy - do you get more delta V from that compared to a rocket of the same mass?<br /><br />How about the effect on the mother ship - will the tether maneuver lower the ship's orbit so that it has to be boosted by some means?<br /><br />In general - is the tether an efficient way to deliver cargo from orbit?

 

[webtaz99]

I believe the point was a less expensive technique, rather than a more efficient one. <div class="Discussion_UserSignature"> </div>

 

[CalliArcale]

Correct -- the idea is to be cost-efficient, not schedule-efficient or even energy-efficient. <img src="/images/icons/wink.gif" /> It would be fantastic. One of the big impediments to space-based manufacturing is that it's not just expensive to send up the raw materials; it's expensive to bring the products back down. A lot of effort has been focused on reducing the upload cost; this tries to tackle the download cost. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[usn_skwerl]

i googled to find an animation or video of this. i found it. prior to seeing the video, i was having a hard time understanding it. very cool setup!!<br /><br />now, as stated, its not the most efficient way of getting stuff back on terra firma, but it IS a pretty cool way to do it. an small added module onto the ISS would seem fairly easy, all ya really need is a couple of sturdy C-clamps. would make returned cargo (like science experiments, hand-written letters, tax forms <img src="/images/icons/wink.gif" /> , empty supply containers, etc) a little more efficient, versus wasting space and mass onboard a progress or shuttle. <br /><br />hats off to the YES2 folks. this is a pretty sweet setup. any update on why the tether got jammed? <div class="Discussion_UserSignature"> </div>

 

[askold]

I thought it was a pretty clever use of physics - the pendulum and all that. I'm just not sure it's efficient.<br /><br />Didn't the IIS folks recently de-orbit something (an old part of some kind) just by flinging it backwards relative to the direction of flight? Can this tether be a "better" way of de-orbiting experiments - compared to just flinging the object with a big spring?<br /><br />I guess if they can retrieve the tether then the system would be reusable - unlike a rocket.

 

[askold]

Glitch

 

[askold]

Glitch