L1ma April 4, 2012 04:07 AM The problem with using the bungy cord method to tether the cube sats is that Newtons laws of motion still apply. In this case on the other cube sat, like a bat and ball. The casing may be built like a brick, but the Solar Cells, Aerials and Ion Engines/Thrusters with their delicate palladium gauze are not.If it was an Orion sized Spacecraft with the cube sat at the end of the tether, it could be reeled back in and the energy stored in flywheels and shock absorbers in the payload bay. Which may be the better method, with cube sats docked together they house a 300 metre monofilament carbon fibe cable with a tiny light penetrator with your sticky surface which is fired onto the moons surface, springs out and then reeled back in.Your choice NASA. Slowburn April 4, 2012 06:39 AM re; L1maThe two cubes do not need to reel themselves back together once they have escaped Phobos the sail craft can maneuver to dock with the lander cube. All that is needed to lift the lander is a simple friction brake to prevent shock when the tether runs out of slack. Mr Stiffy April 4, 2012 06:52 AM Ode to the idea of an unlimited budget, an unlimited R&D, an unlimited fuel supply and an unlimited amount of space craft.And a HUGE poo-poo to the DNA frying galactic radiation and the apparent light speed limitation. L1ma April 4, 2012 01:49 PM Re; SlowburnFriction breaking does work, but I would hope to apply it to the reel, not the line. A larger surface area is available in the reel which would also house both motor and flywheel, with less chance of the break pads breaking off and severing the cable.Because the escape velocity of Phobos is 11.3 ms it may be even better to drop the paired microsats onto the surface in the form of a lander by aiming ahead of the orbit of Phobos and simply drifting onto it, using one of them to fire the other half back to earth. L1ma April 4, 2012 01:54 PM re; SlowburnStill there is the problem of trying to even out forces in 3 dimensions on 2 objects now acting upon each other via a cord at several hundred meters above a large rotating body 30 minutes transmission away from your control room. Slowburn April 5, 2012 05:15 AM re; L1maSense they are in orbit around Mars with only the slightest bit of encouragement the two masses at the ends of the cord will assume an orbit at the center of the combined mass. One will be high the other will be low by severing the cord at the lander cube it will enter a predictable orbit and then sever the cord from the sail cube reducing the mass. If you used a reel get rid of it as well. Then as I said before fly the sail cube into docking. DR.ZARKOF April 5, 2012 06:38 PM It would be nice if this article gave a timescale for this mission. Are we talking years or decades to travel this energy free superhighway? L1ma April 6, 2012 12:08 PM re: Dr.ZarkofThe usual gravity assisted path usually takes years off a journey, borrowing energy from a planet and giving speed to the Micro sat (The Voyagers and Gallaleo missions). The cubesat pictured has solar sails, sending it close to the sun would give it a vast initial speed boost especially if Mars is in opposition to the Earth both from gravity assistence and the solar wind, but you are right the point of the solar sails is free thrust through the path of least gravital resistance through planetary Lagrange points which as you correctly surmise will be years longer than necessary.In other words a mission which will take years to arrive, using space tethers which have the highest rate of failure of any space technology to the planet which also has the highest mission fail rate. Slowburn April 7, 2012 01:43 AM re; L1maGiven the energy budget minimum power required path is the minimum time path. This is why you don't want to use a reel to bring the two modules back together. L1ma April 7, 2012 07:27 AM re; SlowburnNot quite true, Most efficent and quickest are not the same thing, if you send your probe through the most energy efficient route I believe it would take 2 - 4 years, the quickest journey time to Mars is 6 months or less at near closest approach. This is with nuclear powered rockets, the quickest route is always dependant upon borrowing speed from a planets mass as well as having the most powerful propulsion, when Mars is at opposition the plan is to use a Venus slingshot orbit to gain velocity.If you use the slow route, and the Chinese get to know about it, the China mars orbiter return sample probe will use the fast option. Chang'e 2 has already completed its moon mission and has been moved to the Earths L2 point, the next version only needs larger fuel tanks(Chang'e 3 in 2013 is meant to have a sample return rover). However you get there it takes the same amount of energy to get to the Moon as to Mars. But its pointless to be the first to get there and the last to return, the only credo to using Micro sats is that you send a cloud of them at the same time with the knowledge that the high failure rate of Mars missions means at least one will return. So far we have no sucessful use of space tethers or solar sails either.