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Roll Out Solar Array (ROSA) headed to the ISS by manboy on 11 Jun, 2016 05:48
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"The U.S. Air Force has funded a test flight of the ROSA mechanism, now scheduled for a SpaceX launch in Spring 2017 (SpX-11) to the International Space Station, where it will be deployed in space."
http://www.nasa.gov/feature/roll-out-solar-array-technology-benefits-for-nasa-commercial-sector
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#1 by manboy on 11 Jun, 2016 05:50
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"ROSA is stowed in the trunk of the SpaceX’s Dragon capsule during launch. Once on orbit, the ISS robotic arm removes ROSA from the Dragon trunk and temporarily stows it on an ELC. When ROSA operations are ready to begin, the ROSA is picked up by the ISS robotics arm and located in its operations location. The ROSA operations are conducted while attached to the SSRMS/SPDM for a duration of 7 days."
http://www.nasa.gov/mission_pages/station/research/experiments/2139.html -
#2 by Star One on 11 Jun, 2016 07:20
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Useful I would think for interplanetary probes that need vast arrays when sent to Jupiter and beyond
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#3 by Ronsmytheiii on 11 Jun, 2016 10:55
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Useful I would think for interplanetary probes that need vast arrays when sent to Jupiter and beyond
It would also be useful in the immediate future for the X-37B flights, increasing power and/or reducing size/weight.
Also the same for any AF birds as well (like AEHF) -
#4 by Lar on 11 Jun, 2016 13:08
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A little confused why the AF calls it a "success story" before it's even tested in space...
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#5 by the_other_Doug on 11 Jun, 2016 16:29
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A little confused why the AF calls it a "success story" before it's even tested in space...
Yeah, that's not a news release, it's a PR pamphlet.
C'mon, guys, let's not start congratulating ourselves before we've actually, like, accomplished anything...
edit/Lar: soften -
#6 by Robotbeat on 12 Jun, 2016 01:31
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Useful I would think for interplanetary probes that need vast arrays when sent to Jupiter and beyond
Useful for like everything in orbit inside of Neptune. ~Everything in orbit is solar powered. Everything in orbit can benefit from either reduced mass or increased power.
It's hard to think of anything in orbit that WOULDN'T benefit. I suppose a Hubble-like telescope which needs extremely, ridiculously fine pointing might prefer something a little stiffer, but that's a pretty small list of things. And Hubble did fine for a few years with a similar array. -
#7 by A_M_Swallow on 12 Jun, 2016 01:51
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"ROSA is stowed in the trunk of the SpaceX’s Dragon capsule during launch. Once on orbit, the ISS robotic arm removes ROSA from the Dragon trunk and temporarily stows it on an ELC. When ROSA operations are ready to begin, the ROSA is picked up by the ISS robotics arm and located in its operations location. The ROSA operations are conducted while attached to the SSRMS/SPDM for a duration of 7 days."
http://www.nasa.gov/mission_pages/station/research/experiments/2139.html
(My bold)
Does this mean that the array is thrown away after 7 days? -
#8 by JBF on 12 Jun, 2016 03:15
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This is the best source I've found that explains how it maintains it's rigidity. http://www.dtic.mil/dtic/tr/fulltext/u2/a444956.pdf Does anyone have a link to any more information?
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#9 by Nomadd on 12 Jun, 2016 03:48
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It was quite a way from "just fine" Almost half the observing time was affected by the array jitter. But the problem wasn't as much the flexible array as an improperly designed support arm.
It's hard to think of anything in orbit that WOULDN'T benefit. I suppose a Hubble-like telescope which needs extremely, ridiculously fine pointing might prefer something a little stiffer, but that's a pretty small list of things. And Hubble did fine for a few years with a similar array. -
#10 by Norm38 on 17 Mar, 2017 14:59
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I was told in the CRS-11 thread that this will have a dummy load. I'm curious how they plan to dump the waste heat. Does it include a radiator assembly?
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#11 by speedevil on 24 Mar, 2017 10:55
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I was told in the CRS-11 thread that this will have a dummy load. I'm curious how they plan to dump the waste heat. Does it include a radiator assembly?
I do not know any details, but it would be quite easy to construct a little canned device with a reflector, insulated on one side, and n*1kW halogen bulbs in it.
Pointed in the same direction as the solar cells, and it just emits heat back to the source.
Could be quite light indeed, no need for extensive low-temperature radiators. -
#12 by jcm on 01 Apr, 2017 05:49
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"The U.S. Air Force has funded a test flight of the ROSA mechanism, now scheduled for a SpaceX launch in Spring 2017 (SpX-11) to the International Space Station, where it will be deployed in space."
http://www.nasa.gov/feature/roll-out-solar-array-technology-benefits-for-nasa-commercial-sector
It would be nice if we could get a less blurry image of the top picture (ROSA as packaged for ISS). -
#13 by speedevil on 07 Apr, 2017 12:38
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No reply to an email to the project leader at an airforce address on questions of watts and kilos and other things. I guess closer to launch, or even on orbit maybe.
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#14 by rerickson on 12 Apr, 2017 18:14
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Some details from this paper: the longerons are split tubes, flattened and rolled up lengthwise for launch. The Elastic Memory Composite material freezes in that configuration; sunlight is used to heat the outside of the roll, causing it to slowly extend and un-flatten into its original shape. I didn't read the entire paper, but it sounds like this allows deployment without a motor or speed-control device; clever!
This is the best source I've found that explains how it maintains it's rigidity. http://www.dtic.mil/dtic/tr/fulltext/u2/a444956.pdf Does anyone have a link to any more information?
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#15 by Riley1066 on 20 May, 2017 12:43
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It would be cool if they could figure out a way to permanently hook this up to the ISS power system after the experiment is over ...
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#16 by Nilof on 20 May, 2017 19:58
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Do we know what the mass and power output of this prototype are? Also, I find it really cool that it's possible to fit a huge panel of this kind into the Dragon's trunk.
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#17 by SWGlassPit on 21 May, 2017 02:07
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It would be cool if they could figure out a way to permanently hook this up to the ISS power system after the experiment is over ...
This one is a small scale tech demo, but stay tuned... -
#18 by mtlapointe on 01 Jun, 2017 14:47
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Hi all!
One of the Principal Investigators for the ISS Flight Experiment here. Glad to see so much interest in ROSA! Thought I could answer a few of your questions above:
Lar/the_other_doug: Yes, this is our first demo of ROSA in space. Our company is still fairly young, but we have fully qualified several different ROSA architectures on the ground. As you know, getting prime's to bite on new technology takes time, so hopefully this Flight Demo mission will lead to many more flight success stories.
Robotbeat: We agree! Our main goal with ROSA is to decrease mass as much possible, while also decreasing cost and increasing reliability. We do get compared with the Hubble arrays, but it's important to note that our deployment boom are composite, so they do not suffer thermal snap issues like the Hubble arrays did. We also do not require any motors to deploy the array.
A_M_Swallow: Yes, unfortunately after 7 days, we will retract our wing and get stowed back on the trunk for disposal. As part of safety requirements, we have to latch the array when we retract and cannot redeploy. There is no practical use of keeping us on station after that event.
Nommad: The Hubble arrays used metallic stem deployment booms that suffered from thermal gradients. Our composite booms have very low CTE, and are very stable from hot to cold swings.
JBF/rerickson: No, that design is not the same as ROSA. We use composite booms that self-deploy with their own strain energy. We don't use EMC materials.
Norm38/speedevil: We do not have a radiator. As with most solar arrays, heat is dumped from the backside of the array facing deep space. This demo mission only has a couple active solar cell modules however. The majority is mass simulators. Our primary objective of the mission is not to test power production capability, but rather the deployment mechanism. We will not have great lighting due to our position on station during the demo, so it would be a waste of money to fully populate the array.
Riley1066/Nilof: We only have a couple actual power producing solar cell modules for this demo, so there would be not practical use attaching to station. An array this size would be in the 2-3 kW range. The mass of this demo array is a bit heavier than would be for a real mission - the booms are much larger to demonstrate scale-up capabilities and many metallic parts would be made from composites for a real mission. Cost and safety precautions of ISS prevented us from using more composites.
The size of this demo was limited by our available room in the Dragon trunk. We would have loved to test as large of a wing as possible. Our ROSA technology could certainly be used to add additional power to ISS, and given more room in the trunk, we could pack in a much larger array. We have many different configurations of ROSA, including a stowed folding version, that could pack twice the power in a similar stowed volume.
Also - I've attached a photo for you all of the stowed array from yesterday's media briefing.
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#19 by mtlapointe on 01 Jun, 2017 14:59
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I've also attached our Mission Patch for ROSA.
