September 2013 - AMSAT-BB - mailman.amsat.org

Re: Path to HEO
by Samudra Haque 05 Sep '13

05 Sep '13

Hello, Perhaps my recent work may stimulate discussion in this thread, though it has not been proven in Space yet, but ... my George Washington University MAE dept. micropropulsion subsystems for small spacecraft was highlighted in the September 3 issue of the School of Engineering and Applied Sciences newsletter. If you have the time, please see the following web video that shows the first ever firing of three simultaneous microthrusters. These subsystems were developed under Dr. Michael Keidar, and are products of the GWU Micro-Propulsion and Nanotechnology Lab. It should play well in all web browsers, PC, Mac or Mobile. https://docs.google.com/file/d/0BzYYl-b0DOFWZ1U0RFBYdU93NW8/edit?usp=sharing Thrust range is 1-50 uNs (impulse-bits, variable, programmable) per channel. Different clustering/arraying/firing sequences possible. Available 2013. Looking for a ride to Space for qualification to higher TRL. We are at TRL5+ now. 73 de Samudra/N3RDX newsletter excerpt: *The Micro-propulsion and Nanotechnology Laboratory (MpNL),* led by* Prof. Michael Keidar (MAE), *participated in the 27th Annual AIAA/USU Conference on Small Satellites, held August 10-15 in Logan, UT. *MAE doctoral student Samudra Haque p*resented dual operational prototype hardware examples of his research focus,* “Micro-Cathode Arc Thruster (µCAT) Subsystem for In-space Propulsion of Small Satellites,” *and explained to audiences its applicability for space missions and its technology readiness level for testing in the 2013 GWU/NASA Ames Research Center investigative project, “Micro-Cathode Arc Thruster PhoneSat Experiment.” *Micro-propulsion and Nanotechnology Laboratory (MpNL) *students have successfully completed, for the first time ever, a full integration and testing of a prototype 3-channel Micro-Cathode Arc Thruster (µCAT) subsystem at NASA Ames Research Center (ARC). This was specifically engineered for the ARC Center Innovation Fund 2013 award project, “Micro-Cathode Arc Thruster PhoneSat Experiment.” The project was intended to explore the viability of enabling the innovative Google Nexus SmartPhone-powered series of small spacecraft to have full attitude and orbit correction capabilities. Three of these spacecraft were flown and operated in space in April 2013 onboard the Antares launcher by Orbital Sciences from Wallops Flight Facility, VA. On Fri, May 3, 2013 at 1:56 PM, M5AKA <m5aka(a)yahoo.co.uk> wrote: > Can't remember if the links on the work of N1BCD were posted earlier: > > Video of presentation at > http://www.ustream.tv/recorded/22959312/highlight/267762 > > Slides > > http://icubesat.files.wordpress.com/2012/06/icubesat-org-2012-c-1-1-_presen… > > IARU Coordination > http://www.amsatuk.me.uk/iaru/formal_detail.php?serialnum=305 > > 73 Trevor M5AKA > > > > > > _______________________________________________ > Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >

2 1

A0 40 replacement (PSK31-Best of FM and Linear!)
by Robert Bruninga 05 Sep '13

05 Sep '13

> As long as AMSAT-NA needs to concentrate on... Cubesats... > I would really like to see the pursuit of linear transponders... > on them instead of single-channel FM repeaters. We can have the best of BOTH FM and Linear! > But we used to use a ucc1 in the navy to receive messages. > http://www.virhistory.com/navy/rtty-mux-ucc1.htm > It would allow us to receive something like 16 or 32 separate traffic channels on one frequency. We have that now in PSK31. Up to 30 channels in a single audio channel. So the ideal AMSAT transponder is a linear receiver (on 28.120 MHz) and an FM downlink of that single channel on UHF. This has the advantage of 30 individual linear uplinks to share amongst everyone, and the advantage of FM downlink so that everyone gets the same waterfall without added Doppler. It's a win/win. And it is FULL duplex so that everyone can transmit simultaneously and everyone can receive everyone simultaneously. What more fun can that be!!! See the design: http://aprs.org/psk31uplink2.html And it all fits on a single 3.4" circuit board. Easy to fit in any Cubesat. Two such flight ready boards are ready by the Brno University in the CZECH Republic. Bob, WB4APR

2 1

Re: AO-40 Replacement
by Rob 05 Sep '13

05 Sep '13

I miss linear transponders .... I grew up with the early RS birds particularly RS-6 and RS-8 .... I was only a "kid" in college ... If you're looking for EASY ENTRY .... MODE A ROCKS! That said .. I never bother with the FM birds .... tried once and it's was just a barrage of callsigns and grids .... I've been sticking with FO-29 and VO52 ... I need to give AO7 a try Also ..... if anyone is looking for a great transponder module for a cube sat ... look no further than the work of PE1RAH .... his transponder fits in a "cube" and is already flight proven .... High elliptical orbit satellites are cool .... harder to work ..... more transmit power ... receive preamps ... probably not entry level stuff ... I'd a rather see a couple LEO linear transponders rather than ONE HEO ... --> Rob, KA2PBT

2 1

Another Delay For Next SpaceX Launch
by B J 05 Sep '13

05 Sep '13

http://innerspace.net/2013/09/05/spacex-launch-update/ Meanwhile, SpaceShipTwo finishes another powered test flight: http://moonandback.com/2013/09/05/spaceshiptwo-completes-second-powered-fli… http://www.parabolicarc.com/2013/09/05/spaceshiptwo-completes-powered-fligh… 73s Bernhard VA6BMJ @ DO33FL

1 0

Re: A0 40 replacement
by Zach Leffke 05 Sep '13

05 Sep '13

Just throwing this out there: 1. University cubesats tend to want to occupy amateur satellite service spectrum for their science missions, V/U is common. 2. Most *science* missions are only designed to last a few years, but the orbits will last a while longer. 3. How many science missions have been completed, but the spacecraft is still in orbit and occupying amateur spectrum? (I don't know the answer but I suspect it's a decent number, probably out of single digits and into double digits, see http://www.nasa.gov/directorates/heo/home/CSLI_selections.html to get an idea of the number of cubesats going up from universities, note the number of "in work") 4. What if those university spacecraft carried Software Defined Radio technology as their primary method for delivering their mission data to the ground? 5. What if upon completion of their mission the universities turned over control of the spacecraft to AMSAT. 6. AMSAT then reconfigures the spacecraft such that the SDRs are now used for voice or data relay (FM, Linear, packet, whatever). 7. Now all of a sudden, hams don't have to wait for a new spacecraft to get built and find a launch. Birds already in orbit, that are using Amateur Spectrum, now all of a sudden are providing a service to the Amateur community. Personally, I'm glad the universities are using Amateur Radio spectrum for their science missions. I view the skies as a "target rich environment" even if all I can do is listen to these birds. However, it would be nice if the birds occupying amateur spectrum actually provided a service to the amateur community. But what if the SDX that flew on ARISSat, or the one that will be developed for the Future of the Fox series could be "sold" (or given) to the university cubesat community as a radio capable of being used to deliver science data? Their science mission concludes, control is turned over to AMSAT, the radios are reconfigured, and they become transponder birds for the ham community. At the rate that these spacecraft are going up, even if we nab only 10% of the spacecraft listed on the link above and convince them to fly SDRs that can be reconfigured, that's roughly 9 satellites that over time become useable by the ham community as voice/data transponders. We don't have to build them, we don't have to find a launch, we don't have to do anything but wait until the science mission is over and then play. Will the spacecraft be of the same quality of what comes out of AMSAT? Maybe, maybe not, but even if one only lasts a year as an FM or Linear Transponder, I'd take it, and use it. Granted, who knows what the orbits would be, so a replacement for AO-40? Probably not. But would the Amateur Satellite community accept maybe instead of 1 really long pass from a HEO bird, maybe in that same time frame 10 or 20 or maybe even 50 passes from multiple lower birds (I made these numbers up, no idea what the actual numbers would be)? Granted, there is a LOT that would go into making this idea possible. We'd have to have an SDR the universities are willing to use, probably one with flight history (cough, Fox-2, cough). We'd have to have someone go around to the Universities and "sell it" to the Principal Investigators that our radio will work for them (technical issues aside, maybe they get a little PR by adding support for the Amateur community onto their list of mission objectives). If they agree to fly the radio, and then turn over control, we need to be capable of supporting those spacecraft from an Operational point of view when the time comes. We would need to have some sort of "filter" such that if they drive the heck out of their spacecraft to the point that it is nearly dead when their science mission concludes we have the option to reject taking the spacecraft over. Etc. Etc. Etc. There's a lot of "what ifs" up there, but my favorite "what if" to think about is: what if the 89 satellites on that link above were capable of supporting amateur use at the conclusion of their science missions (Fox-1 is on that list, so ok 88 satellites)? 89 satellites + what AMSAT has and is still putting up? Can't make a contact during field day on an FM bird because of crowding, no problem, you have 5 other satellites to choose from and try. My second favorite "what if" to think about is: what if the university cubesats occupying amateur spectrum actually provided a service to the amateur community? A traditional replacement of AO-40? No. Effectively reproducing the similar amounts of access time and capabilities of AO-40? Maybe. Like I said, just throwing the idea out there... -Zach, KJ4QLP

5 5

Re: AO-40 Replacement
by Clint Bradford 05 Sep '13

05 Sep '13

>> ... launch opportunities are so rare that we ought to fly the most capable equipment we can on those rare occasions when we can get a launch ... Perhaps we should define, "most capable equipment." And we also need to define "bang for the buck." What should a ham satellite program offer to the amateur community? If bringing new hams into this aspect of the hobby is important, then we need another AO-51 - which was probably the greatest marketing tool ever seen in the amateur satellite community. Its ease of use was the cause of scores of media alerts and publicity for amateur radio. And most importantly, it got more people looking skyward and thinking they could work amateur satellites than any other project. Then there was the marvelous marketing surrounding ARISSat-1 ... What else should an amateur satellite program offer? Many here want satellites that are only accessible with an investment of many hundreds of dollars' worth of antenna systems and equipment. (Some would actually love it if Technicians weren't allowed - that's how extreme thinking is on this topic.) Is THAT what will move the hobby forward for the masses? IS there a "middle ground?" Sure is a polarized topic (pun intended). Some want the hobby and sat use to grow ... others want to exclude as many fellow hams as possible. Clint Bradford K6LCS http://www.work-sat.com ---------------------------------- Clint Bradford, K6LCS http://www.clintbradford.com

4 6

Say "Hi" To Juno (Callsign end's with "F")
by Les Rayburn 05 Sep '13

05 Sep '13

I reached out to JPL to ask what the desired frequency for this experiment would be if your amateur callsign ended in the letter "F". Here's the response: /Hi Les- What a strange thing for us to leave out! The omission will be corrected in our next update of the page this week. In the updated frequency table we will publish, F corresponds to 28.091 MHz. Thanks for your interest in this activity!/ Cheers, Preston Dyches Solar system & technology public engagement NASA - Jet Propulsion Laboratory MS 230-275 4800 Oak Grove Drive Pasadena, CA 91109 -- -- 73, Les Rayburn, N1LF 121 Mayfair Park Maylene, AL 35114 EM63nf 6M VUCC #1712 AMSAT #38965 Grid Bandits #222 Southeastern VHF Society Central States VHF Society Life Member Six Club #2484 Active on 6 Meters thru 1296, 10GHz & Light

2 1

D STAR AMsat users net
by damon runion 05 Sep '13

05 Sep '13

D Star Amsat users net tonight at 01;00 UTC on REF 60 B Hope to see you there with news about grid trips new operators and things you may want to sell or buy Satellite news ? https://sites.google.com/site/memphisdstar/d-satellite-amsat-net Damon WA4HFN em55 Memphis, TN

1 0

Re: SO-50
by Clint Bradford 05 Sep '13

05 Sep '13

>> ... As long as we have these self proclaimed Satellite Instructors neglecting the benefit of Full Duplex operation ... Who are these "instructors?" Seems that would be a much smaller "target audience" for us to educate. Every audience I have ever presented my sat show to (more than 73 shows, a few thousand attendees) have heard me state, "It is preferable to work the FM birds full-duplex, where you can monitor the downlink as you key your mic ... " - and I explain simple ways to accomplish that. Same "mantra" in a couple of CQ Magazine articles ... and during a Bob Heil / Gordon West "Ham Nation" segment ... same as I have written for Gordon West's licensing manuals ... Well, with just this one "easily-worked" bird (not counting the ISS) up there, now more than ever should we be stressing working duplex. But to be honest with you, after reading another thread yesterday regarding the "out of control" nature of SO-50, I had to see for myself what the "problem" was. So I worked a mediocre pass (about 25 degrees - and I only worked the first few minutes - BEFORE it was at its best elevation. I worked three states sitting on the grass out in the back yard with my demo setup of FT-60R and Arrow. (Don't tell anyone, but I did not work full duplex - I needed to see if I could experience the total failure to communicate that a couple others have written about. And try as I might, I couldn't fail ... After I made one call successfully, two others called me from around the country.) YES - it got a little chaotic. YES - there were cases of people stepping on others. But it was not as gruesome as some have written - not as bad as a Field Day or a special event weekend. Heck, it was a FEDERAL HOLIDAY in the U.S., and I had no problem working three states with 2 Watts during the beginning of a 25 degree pass. Are people getting into this aspect of the hobby with unrealistic expectations? And if they are, where are they getting their information about working the FM birds? Clint Bradford K6LCS http://www.work-sat.com 909-241-7666 - cell ---------------------------------- Clint Bradford, K6LCS http://www.clintbradford.com

22 32

Re: A0 40 replacement - mode K cubesat?
by Ross Whenmouth 05 Sep '13

05 Sep '13

Hi, How feasible is it to fly a mode K (15m uplink, 10m downlink) linear transponder on a cubesat? I expect that retty much any ham with an HF transceiver would be able to work this bird, and I expect that due to the lower frequency, the footprint might be a bit larger than that of VHF/UHF bird in the same orbit and doppler shift would only be about 7% of that experienced on 70cm. The biggest problem that I see though is squeezing a somewhat efficient 10m antenna into a cubesat and deploying it by remote control once on orbit. (I think that the cubesat antenna should be optimised for TX performance, as cubesat TX EIRP capability is severely limited compared to the average HF transceiver). Would two 2.5m lengths of steel tape (the same stuff that tape measures are made out of) - mounted on opposing sides of the cubesat, be able to unroll in microgravity to form a generally straight 1/2 wave dipole with a low risk of tangling, snagging or kinking, etc? Alternately, what about using some sort of thin plastic tubing (something like dialysis tubing, but suited to the space environment?) with a wire inside it, and rolled up. Then, once on orbit, the tubing is inflated with self-expanding polyurethane foam, which will extend the tube (and the wire inside it). The foam will then harden, so future loss of gas pressure in the plastic tube (micrometeorites?) will not cause failure of the antenna? 73 ZL2WRW Ross Whenmouth

2 1