The SkyClimber

[jimfromnsf]

"the tangent force is the force acting along the tangent line to a circular motion, "<br />has nothing to do with the material properties of a cable. <br /><br />He said "Sudden tangent forces acting on a body, a cable, are different than tensile forces, such as sheer strength forces etc.'<br /><br />There are no sheer forces in a cable

 

[j05h]

<i>>>80kg/1760lb. How much for does that exert, climbing to 70mph?<br /> />Do you mean 800 kg and I thought they said 70 km/hr with a acceleration rate of 3.8 m/s not 70 mph, that’s a big difference. At 70 km/hr that is about 43.5 mph. </i><br /><br />Sorry. 800kg moving at least 70kph, probably closer to 230kph (Pathfinder velocity before retros). Pathfinder cut the tether at about 40'/12m and still could have hit the surface at up to 56mph. <br /><br /><i>> I would favor a belt made out of Spetra</i><br /><br />That works, as long as the winch can grip it and it has the required strength. Plastics are so amazing. One big factor is brittleness - Spectra gets brittle at potential deep-space and near Mars nighttime temperatures, per your post. <br /><br />The only way I can see something like this would be if the winch is somehow reused for climbing/lowering sensors or something. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[holmec]

<blockquote><font class="small">In reply to:</font><hr /><p>Has various steel cables.<p><hr /></p></p></blockquote><br /><br />STEEL?! <br /><br />Why not use something stronger and lighter like rope made from [ure=http://[url=http://www.wakecord.com/spectra.htm]www.wakecord.com/spectra.htm[/url]]Spectra fiber[/url]? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[j05h]

<i>> STEEL?!<br />Why not use something stronger and lighter like rope made from [ure=http://[url=http://www.wakecord.com/spectra.htm]www.wakecord.com/spectra.htm[/url]]Spectra fiber[/url]?</i><br /><br />Steel because it was easy to calculate via Google search. Spectra has already been suggested, it's fine, too. The Skyclimber has issues regardless of cable choice.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[windnwar]

Spectra would never survive the temperatures though, the trip there it'd have to be heated the entire way or it'd turn brittle. Spectra is great stuff in a normal climate but UV, heat and cold, degrade it rapidly. <div class="Discussion_UserSignature"> <p> </p><p><font size="2" color="#0000ff">""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein"</font></p> </div>

 

[spacehappy]

You would have to store it in a temperature control area on its journey to Mars, it is highly resistant to UV and the rope or belt could be insulated like electrical cords and only unfurled and used in a short time period. <br /><br /> TEST (Pounds) Diameter Weight per 1000' <br />40# .010" 1.2 oz. / 1000' <br />80# .015" 2.3 oz. / 1000' <br />130# .020" 2.86 oz. / 1000' <br />200# .023" 4.17 oz. / 1000' <br />300# .035" 8.75 oz. / 1000' <br />500# .051" 12.75 oz. / 1000' <br />1000# .112" 38.4 oz. / 1000' <br /><br />http://windstarkites.com/FlyLine-SportandStuntKiteLine.htm#DiameterSpectra<br />

 

[j05h]

I already mentioned Spectra getting brittle on the trip outbound - another potential argument for steel, kevlar or titanium. <br /><br />No one even wants to discuss the mass of the winch? C'mon, that's the REAL kicker to the SkyClimber.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[spacehappy]

<font color="black">No one even wants to discuss the mass of the winch? C'mon, that's the REAL kicker to the SkyClimber.<font color="white"><br /><br />Consider what they are replacing to make this work, the Skycrane.<br /><br />You would have to consider the mass of everything used on the Skyclimber to make this work, the wrench would add mass but there are several light weight materials that can be used for that. The mass of the wrench or flywheel type energy recovery (hybrids hub system or surgical tubing?) as mentioned at the web site + mass of electric motor + mass of batteries or ultra capacitors (ten seconds worth of stored energy at the acceleration rate of 3.8 m/s) + mass of the belt/ rope. <br /><br />The Skyclimbers total mass may pail in comparison to the total mass of the Skycrane, the mass of the Skycrane propellant alone is over 250 kilograms. I would guess that the Skycranes total mass will come in over 1000 kilograms. Does anyone have information about the Skycranes finished mass; I bet they aren't going to release that information until the MSL stops gaining weight.</font></font>

 

[windnwar]

To handle the weight, and speed that winch is not going to be small. Your talking about 10 seconds of accelaration right. You'll need very high torque hence the reduction gears, those gears will need to be of a hardened material. Spool housing that the motor and gearbox attach too, strong enough to keep it from flexing and causing the spool to bind with enough extra space to allow the cable to roll in at a high speed while not causing a lump to form and begin rubbing the sides of the housing. Batteries to supply power, as currently we have no capacitors that can do the job, might change in the future but at present only batteries will work. Since they are going to be running what will no doubt be a high draw motor, you'll need to have enough battery power there to reduce the risk of overheating and burning up battery pack. Heaters to keep all the components warm during the trip. <br /><br />I think the biggest weight issue will be the battery pack, followed by the winch. Size will be the next biggest issue for the winch unless you can come up with a way to coil the cable back on the spool at high speed without it snagging, forming a lump of cable on the reel or creating a rub point on the cable guide that will end up heating and damaging the cable, this being more of a concern using spectra type cable. <br /><br />Those are some pretty big hurdles to overcome. Retros on the other hand are well understood, have a very high energy density and have been proven to scale up as the load increases. <br /><br />I think its an interesting concept but I think it's going to be far more successful on earth then on mars and really only work well with small loads but i'll leave that bit to the people smarter then me to figure out. <div class="Discussion_UserSignature"> <p> </p><p><font size="2" color="#0000ff">""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein"</font></p> </div>

 

[spacehappy]

<font color="black">I think the biggest weight issue will be the battery pack<br /><br /><font color="orange">A supercapacitor or ultracapacitor is an electrochemical capacitor that has an unusually high energy density when compared to common capacitors. They are of particular interest in automotive applications for hybrid vehicles and as supplementary storage for battery electric vehicles.<br /><br />Other advantages of supercapacitors compared with rechargeable batteries are extremely low internal resistance or ESR, high efficiency (up to 97-98%), high output power, extremely low level of heating, and improved safety. According to ITS (Institute of Transportation Studies, Davis, CA) test results, the specific power of supercapacitors can exceed 6 kW/kg at 95% efficiency, see APCT Prototype Test Results<br /><br />The FIA proposed on May 23rd, 2007, in the Power-Train Regulation Framework for Formula 1, version 1.3, that a new set of power train regulations be issued that includes a hybrid drive of up to 200 kW input and output power, involving both batteries and supercapacitors.<br /><br />http://en.wikipedia.org/wiki/Supercapacitor<br /><br /><font color="white">Note all you have to do is charge them up before releasing them from the mother ship; don’t have to carry the heavier battery mass to the surface. Some ultracapacitor makers claim that theirs can hold a charge for two weeks. If they can hold a charge for two weeks then you wouldn't even need to carry any batteries or other storage device with you, just use the solar panels. Two weeks worth of charge for 10 seconds of use, quite large amount of charge can be stored this way.<br /><br />Some of this information I have been getting off of http://arrow-space-innovations.com web site for the past month and I have since confirmed their sources, they posted it then you don’t see it again. They</font></font></font>

 

[CalliArcale]

Alas, image uploading is currently broken. <img src="/images/icons/frown.gif" /> <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>

 

[spacehappy]

Thanks for that information. <br /><br />Another interesting analogy about the Skyclimber is that they claim it is similar to stopping at a stop sign when you get close to the Martian surface. If the number for the induced drag is right for two large parachutes 134 ft diameters then they are traveling approximately 43.5 mph before they have to suddenly stop. <br /><br />According to one of the previous items posted on their website the Skyclimber would have to start stopping 85 m (279ft) above the surface. With electronics it is almost instantaneous compared to human reaction time, the speed of ascent could be controlled all electronically just like a brake peddle. <br /><br />The Skycrane uses a radar altimeter to tell what its speed of descent is and according to them and they are basically doing the same thing decelerating to a safe landing speed before landing. They claimed that the skyclimber would use the same altimeter device, only electronic reaction time is much faster than chemical thrusters and human reaction time so the distance traveled while a human reacts to an impending sudden stop is left out of the distance it takes to stop. I looked it up a human with reaction time would stop at an approximately 42 m (138 ft), this is hypothetical since it depends on different set of conditions and we are comparing different laws of physics but the analogy is a good one. <br /><br />When you get to Mars after most all the kinetic energy is drained out of the descending craft before reaching the surface then all you need to do is simply put on the brakes. Applying the brakes is started by the heat shield then supersonic parachute, then the two large subsonic parachutes then the brakes (the skyclimber) all this coming in at below the total mass of the skycrane , including adding the two large parachutes. They apply the brakes by simply accelerating upwards to close to its descending speed that basically is what the skycrane does, what a novel idea.<br />

 

[jimfromnsf]

"he skyclimber) all this coming in at below the total mass of the skycrane , including adding the two large parachutes. "<br /><br />This is doubtful and no proof has been provided. Also how are crosswinds handled?<br /><br />And what happens when the climber is accelerating and a gust "pushes" down the chute? There will be a rat's nest in the cable

 

[gunsandrockets]

<A weakness in current approaches they point out is that the parachute designs in use today are the old Viking design with a single disk+cylinder chute. They said the necessary testing to develop new hypersonic parachutes is quite expensive.> <br /><br />What is the largest Mars parachute flown (or tested)? I get the impression that parachute design is more art than science. So there might be serious limitations to scaling up a parachute for landing larger payloads in the alien environment of Mars.<br /><br />Once upon a time the Mars Excursion Module (MEM) for a manned landing on Mars was going to use a ballute and not a parachute. I had the impression the reason for that choice was the huge mass of the MEM (50 tonnes before entry). A ballute is more predictable than a parachute since inflation of a ballute is independant from the external environment, unlike deployment of a parachute.<br />

 

[rlb2]

<font color="orange">Keep posting those Mars Images, that’s one of the only reasons I ever visit here anymore.<font color="white"><br /><br />Thanks<br /><br />I will keep posting them here but not as much as before.<br /><br />Temporarily left, I had some business to take care of last week away from home. The Mars Images have been deleted from the Arrow Space Innovations web site because we are re-inventing ourselves going to a larger web hosting service provider. Hope to be able to continue carry them at our new site with full resolution and may be able to post over 1000 color images, don’t know when that will be finished. The new web site that is still under construction is our transformation into other ventures besides aerospace such as green energy.</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

Thanks<br /><br />In some of our tests we actually accelerated up faster than we came down, the final velocity upwards was more than the descent speed downwards. We are developing this mainly for use on Earth and we think we found a way to use it on Mars. Presenting the SkyClimber at the Mars Society Conference was just one small step, although I got a great welcome there, there are lot's of minds still that needs to be changed and as you can see that is not going to be easy, it is part of the process - the best way to change minds is through proof of concept by showing solid testing here on Earth and for Mars through computer fluids simulation programs that model the Martian atmosphere and access to one of NASA wind tunnels.<br /><br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[spacehappy]

<font color="black">change minds is through proof of concept by showing solid testing <font color="white"><br /><br />True testing leads to even greater discoveries or it can exposes unforeseen flaws, problem is the first real test for the Skycrane as a complete unit will be on Mars where first tests are more prone to failure.</font></font>

 

[rlb2]

We are currently seeking funding at NASA and other places for use on earth. Our testing regiment if we get funding for the Martian SkyClimber would include three different phases of testing, all scalable from one phase to the next, which includes testing in Earths upper atmosphere by high altitude balloons. This can happen inexpensively by the balloon lifting the SkyClimber up to an altitude that has similar atmospheric conditions as the Martian datum. In the meantime here on Earth we hope to soon start our second phase of testing which includes parachute drops with objects of 50 to 100 kilogram mass. <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[rlb2]

Note we are in the process of improving our website and downloading our videos to Google video and YouTube. Here is a temporary spot where you can see the animation presented at the Mars Society Conference on how we think it would work on Mars. <br /><br />http://members.cox.net/skyclimbers/Skyclimber%2008-29-07%203.wmv<br /><br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[spacehappy]

Cool animation the MSLs animation is at - mars.jpl.nasa.gov/msl/gallery/videos.html#MSL_EDL<br /><br />To me the Skycrane is a 900 million dollar accident ready to happen. With just a few modifications, the Skycrane most probably is Lockheed’s first tests for the lunar Lander, no R & D required with a hefty profit to boot, while all the other lunar Lander people are spending there own money with the hope of winning the contract.

 

[rlb2]

Here is an up to date image of how it would work on Earth delivering an all robotic strike force ready to attack once it hits the surface. http://mywebsite.register.com/db3/00284/arrow-space-innovations.com/_uimages/Skyclimber---09-27-07.5.jpg The three lines extending down from the parachute is made of a recoil-like material, bungee cord or surgical tubing the inside cable is attached to the winding device. <br /><br />Most of the initial load after aerial deployment would be held up by the three recoil device lines while a very small load would be on the winding device cable (patent pending) as a result there is a lot of stored energy in the bungee cord that can be tapped. In this configuration there is very little electrical energy needed to propel the robotic vehicle skywards to the desired speed seconds before landing to reduce its overall speed at impact because it taps into the recoil device stored energy. Using recoil like devices will stabilize the load and substantially reduce the amount of energy needed to lift the robotic vehicle up towards the parachute.<br /> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[jimfromnsf]

"the Skycrane most probably is Lockheed’s first tests for the lunar Lander, no R & D required with a hefty profit to boot, "<br /><br />Lockheed has nothing to do with the Skycrane. It is an internal JPL development, no one gets an advantage. It is not applicable to the lunar lander.

 

[j05h]

The thing that makes the most sense, to me, is Viking-style retros that MSL would drop after touchdown. It's to heavy for airbags and I would argue to valuable to use something so untried. I would suggest a set of Earth then Lunar tests before delivering a Mars payload with the SkyCrane (or SkyClimber for that matter).<br /><br />Josh<br /> <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[jimfromnsf]

lunar tests wouldn't provide anything, since parachutes can't be used. also where is the money for a 200-300 million dollar test mission (launch vehicle cost are around 100 million)<br /><br />How were the Viking style and Air bags flight tested? On their first missions. Viking type has been used "once", just as air bags have been used "twice" Dual missions don't allow for lessons learned and readjustment. The same hardware is just built twice<br /><br />There is no more total risk in the sky crane than a viking type<br /><br />A viking type lander would have a smaller rover. Landing on the rover's mobility system eliminates the need for another set of landing gear and roll off hardware.

 

[thereiwas]

What is the mass of the upper part of the skycrane method? I mean as compared to the rover part?