Author Topic: Roll Out Solar Array (ROSA) headed to the ISS  (Read 17178 times)

Offline manboy

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Roll Out Solar Array (ROSA) headed to the ISS
« on: 06/11/2016 05:48 AM »
"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
« Last Edit: 06/11/2016 06:33 AM by manboy »
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Offline manboy

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #1 on: 06/11/2016 05:50 AM »
"ROSA is stowed in the trunk of the SpaceXís 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
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Offline Star One

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #2 on: 06/11/2016 07:20 AM »
Useful I would think for interplanetary probes that need vast arrays when sent to Jupiter and beyond

Online Ronsmytheiii

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #3 on: 06/11/2016 10:55 AM »
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)

Offline Lar

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #4 on: 06/11/2016 01:08 PM »
A little confused why the AF calls it a "success story" before it's even tested in space...
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Offline the_other_Doug

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #5 on: 06/11/2016 04:29 PM »
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
« Last Edit: 06/12/2016 09:55 PM by Lar »
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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #6 on: 06/12/2016 01:31 AM »
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.
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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #7 on: 06/12/2016 01:51 AM »
"ROSA is stowed in the trunk of the SpaceXís 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?

Offline JBF

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #8 on: 06/12/2016 03:15 AM »
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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Offline Nomadd

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #9 on: 06/12/2016 03:48 AM »


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.
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.

Offline Norm38

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #10 on: 03/17/2017 02:59 PM »
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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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #11 on: 03/24/2017 10:55 AM »
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.

Offline jcm

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #12 on: 04/01/2017 05:49 AM »
"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).
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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #13 on: 04/07/2017 12:38 PM »
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.

Offline rerickson

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #14 on: 04/12/2017 06:14 PM »
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?

Offline Riley1066

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #15 on: 05/20/2017 12:43 PM »
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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Offline Nilof

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #16 on: 05/20/2017 07:58 PM »
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.
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline SWGlassPit

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #17 on: 05/21/2017 02:07 AM »
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...

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #18 on: 06/01/2017 02:47 PM »
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.





Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #19 on: 06/01/2017 02:59 PM »
I've also attached our Mission Patch for ROSA.

Offline ThomasF

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #20 on: 06/02/2017 07:53 AM »
Hi mtlapointe,
Thanks for getting into the discussion here!
I was interested in what kind of cell technologies you are using for the ROSA system, but couldn't find any information online. Are those regular single crystal multi junction devices or are you going for more flexible thin film technologies? Or is this simply a company secret  :)

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #21 on: 06/02/2017 06:05 PM »
Hi mtlapointe, welcome to the forum!

This is what makes NSF so great - where else on the internet can you get to chat to a Principal Investigatgor of a space experiment! :)

I have a question for you - could ROSA technology be scaled up to enable it to potentially one day serve as a complete replacement for the current ISS arrays (i.e. same power generation capability, not necessarly same size)? Thanks.
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Offline JasonAW3

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #22 on: 06/02/2017 06:25 PM »
A little confused why the AF calls it a "success story" before it's even tested in space...

Maybe they tested it on one of the classified X-47 flights?
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Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #23 on: 06/04/2017 02:01 AM »
Hi mtlapointe,
Thanks for getting into the discussion here!
I was interested in what kind of cell technologies you are using for the ROSA system, but couldn't find any information online. Are those regular single crystal multi junction devices or are you going for more flexible thin film technologies? Or is this simply a company secret  :)

For most application we would use triple-junction GaAs cells (ZTJ/XTJ cells) with standard coverglass. These give the best combination of cost and cell efficiency, and are what most traditional rigid-panel arrays would use.  However, our ROSA system certainly use flexible thin film technologies or more advance IMM technologies depending on the customers needs.  We also have several different concentrator technologies (reflective and refractive) that we can implement.

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #24 on: 06/04/2017 02:09 AM »
Hi mtlapointe, welcome to the forum!

This is what makes NSF so great - where else on the internet can you get to chat to a Principal Investigatgor of a space experiment! :)

I have a question for you - could ROSA technology be scaled up to enable it to potentially one day serve as a complete replacement for the current ISS arrays (i.e. same power generation capability, not necessarly same size)? Thanks.

Yep, ROSA certainly could be used to replace or augment the ISS arrays. In fact, since ROSA deploys straight out, with almost no additional swept volume vs. deployed volume, it would be a great solution for ISS. Since the current ISS arrays use older, lower efficiency silicon cells (that are peppered with MMOD strikes), the new arrays could be much smaller to provide enough power to keep ISS running.  Let's hope NASA decides to keep ISS up and running!!

 
« Last Edit: 06/04/2017 05:32 PM by mtlapointe »

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #25 on: 06/04/2017 02:11 AM »
A little confused why the AF calls it a "success story" before it's even tested in space...

Maybe they tested it on one of the classified X-47 flights?

I can neither confirm, nor deny this  ;)

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #26 on: 06/04/2017 02:17 AM »
Hi mtlapointe, welcome to the forum!

This is what makes NSF so great - where else on the internet can you get to chat to a Principal Investigatgor of a space experiment! :)

Oh and thanks for the welcoming!  I don't know how I had never stumbled upon NSF before! And I'm equally surprised to see all the interest in our technology. Great coverage of the launch - seems like you can get better info here than some of our inside sources!

Attached is a snap shot of our hardware after the Dragon 2nd stage sep today. Our nominal schedule is removal from the trunk in about 2 weeks, with our demo mission beginning shortly after.  We hope to have portions of the demo streaming live on NASA TV so stay tuned.

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #27 on: 06/13/2017 09:41 AM »
... Our nominal schedule is removal from the trunk in about 2 weeks, with our demo mission beginning shortly after.  We hope to have portions of the demo streaming live on NASA TV so stay tuned.
Looking forward to to see this, now that MUSES is installed and soon NICER ...
« Last Edit: 06/14/2017 07:20 AM by centaurinasa »

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #28 on: 06/13/2017 10:04 AM »
... Our nominal schedule is removal from the trunk in about 2 weeks, with our demo mission beginning shortly after.  We hope to have portions of the demo streaming live on NASA TV so stay tuned.
Looking forward to to see this, now that MUSES and NICER are installed ...
I thought we are waiting for installing NICER today evening.

Offline Star One

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #29 on: 06/13/2017 10:21 AM »
... Our nominal schedule is removal from the trunk in about 2 weeks, with our demo mission beginning shortly after.  We hope to have portions of the demo streaming live on NASA TV so stay tuned.
Looking forward to to see this, now that MUSES and NICER are installed ...
I thought we are waiting for installing NICER today evening.

We are.

Offline gongora

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #30 on: 06/13/2017 01:02 PM »
How is the deployment speed controlled for ROSA?

Offline eeergo

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #31 on: 06/13/2017 01:26 PM »
How is the deployment speed controlled for ROSA?

For deployment, it is reportedly purely controlled by insolation, which causes thermal heating and eventually, exceedance of the glass transition temperature over which the Elastic Memory Composite material releases its stored energy. So it should be a matter of precisely controlling solar insolation attitude over the array.

For retraction, it is mechanically controlled by an incorporated motor, required for re-stowage after the demonstration is completed.

Of course this is just from reading publicly-available sources, possibly Mtlapointe has better info :)
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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #32 on: 06/13/2017 01:31 PM »
How is the deployment speed controlled for ROSA?

For deployment, it is reportedly purely controlled by insolation, which causes thermal heating and eventually, exceedance of the glass transition temperature over which the Elastic Memory Composite material releases its stored energy. So it should be a matter of precisely controlling solar insolation attitude over the array.

For retraction, it is mechanically controlled by an incorporated motor, required for re-stowage after the demonstration is completed.

Of course this is just from reading publicly-available sources, possibly Mtlapointe has better info :)

mtlapointe already said this earlier:
Quote
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.

Offline eeergo

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #33 on: 06/13/2017 02:47 PM »
How is the deployment speed controlled for ROSA?

For deployment, it is reportedly purely controlled by insolation, which causes thermal heating and eventually, exceedance of the glass transition temperature over which the Elastic Memory Composite material releases its stored energy. So it should be a matter of precisely controlling solar insolation attitude over the array.

For retraction, it is mechanically controlled by an incorporated motor, required for re-stowage after the demonstration is completed.

Of course this is just from reading publicly-available sources, possibly Mtlapointe has better info :)

mtlapointe already said this earlier:
Quote
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.

You're right, I hadn't read it quite carefully enough.

Although the question then is: what is the difference between the "Elastic Memory Composites" ROSA does not use, and the "strain energy composites" it does use?
-DaviD-

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #34 on: 06/13/2017 05:57 PM »
https://blogs.nasa.gov/spacestation/2017/06/13/cargo-ship-ready-for-launch-as-robotic-arm-unloads-dragon-experiments/
Quote
A third experiment will be extracted June 17 to test a new advanced solar array. The roll-out solar array, or ROSA, rolls out like a tape measure with solar cells on a flexible blanket. The ROSA, which could power future NASA spaceships and communication satellites, will be stowed back inside Dragonís trunk after seven days of data collection while attached to the stationís robotic arm.

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #35 on: 06/13/2017 06:45 PM »
... Our nominal schedule is removal from the trunk in about 2 weeks, with our demo mission beginning shortly after.  We hope to have portions of the demo streaming live on NASA TV so stay tuned.
Looking forward to to see this, now that MUSES and NICER are installed ...

We are waiting for the arrival of Progress before being extracted, so we should be starting in a few more days.

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #36 on: 06/13/2017 06:50 PM »
How is the deployment speed controlled for ROSA?

For deployment, it is reportedly purely controlled by insolation, which causes thermal heating and eventually, exceedance of the glass transition temperature over which the Elastic Memory Composite material releases its stored energy. So it should be a matter of precisely controlling solar insolation attitude over the array.

For retraction, it is mechanically controlled by an incorporated motor, required for re-stowage after the demonstration is completed.

Of course this is just from reading publicly-available sources, possibly Mtlapointe has better info :)

mtlapointe already said this earlier:
Quote
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.

You're right, I hadn't read it quite carefully enough.

Although the question then is: what is the difference between the "Elastic Memory Composites" ROSA does not use, and the "strain energy composites" it does use?

We use thin composites - carbon fiber, fiberglass, etc. - to provide deployment force.

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #37 on: 06/13/2017 06:55 PM »
How is the deployment speed controlled for ROSA?

We use traditional dampers to control the speed, similar to what would be used on a rigid panel array hinge-line. The specific type (viscous, ECD, friction) depends on the application.  We could also use motors to control the deployment, but we prefer passive dampers for simplicity.

To retract the array, we use a motor and lanyard to "reel in" the array.

Offline Prettz

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #38 on: 06/13/2017 08:48 PM »
This seems like a pretty early technology test, given the short stay on station. Assuming all goes well, what is the next step?

Offline russianhalo117

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #39 on: 06/13/2017 09:02 PM »
This seems like a pretty early technology test, given the short stay on station. Assuming all goes well, what is the next step?
launch a demonstration sat is most likely the next logical orbital step.

Offline jcm

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #40 on: 06/13/2017 11:16 PM »
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.

The NASA CRS-11 launch summary says ROSA mass (for the complete cargo element, but I guess not including the
trunk attach frame) is 325 kg.  Don't know about power.
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Offline nacnud

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #41 on: 06/13/2017 11:22 PM »
The power is just a few cells, this is a test of the mechanical systems. Most of the cells are dummies to save money.

Offline mtlapointe

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #42 on: 06/16/2017 04:27 PM »
This seems like a pretty early technology test, given the short stay on station. Assuming all goes well, what is the next step?

We have been developing this technology for several years now and have fully qualified several systems back here on Earth. Next step to increase the TRL would be a Flight Demonstration, which is what we are checking off the list with this mission. If all goes well, next step would be to implement ROSA as power source for actual commercial and government satellites/spacecraft.

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #43 on: 06/18/2017 08:25 AM »

Offline IRobot

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #44 on: 06/18/2017 09:35 AM »
Hi mtlapointe,

How many W/kg do you expect for a full working system? How does that scale up?

Thanks!

PS: by the way, your webpage needs to be brought to the XXI century...
« Last Edit: 06/18/2017 09:38 AM by IRobot »

Offline Scylla

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #45 on: 06/18/2017 01:11 PM »
ISS Roll Out Solar Array Deployment (Real Speed)

I reject your reality and substitute my own--Doctor Who

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #46 on: 06/18/2017 06:23 PM »
« Last Edit: 06/18/2017 06:47 PM by centaurinasa »

Offline Prettz

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #47 on: 06/19/2017 04:18 AM »
This seems like a pretty early technology test, given the short stay on station. Assuming all goes well, what is the next step?

We have been developing this technology for several years now and have fully qualified several systems back here on Earth. Next step to increase the TRL would be a Flight Demonstration, which is what we are checking off the list with this mission. If all goes well, next step would be to implement ROSA as power source for actual commercial and government satellites/spacecraft.
Sorry, I meant early as in in-space testing. But it sounds like I was wrong about that. If this is the final test before real use as a power source, that's awesome.

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #48 on: 06/20/2017 04:44 PM »

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #49 on: 06/25/2017 01:14 AM »
That the End.... of the first deployment
« Last Edit: 06/25/2017 09:44 AM by centaurinasa »

Offline Star One

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #50 on: 06/25/2017 08:25 AM »
That was very brief. Is it removed now & disposed of?

Offline Skyrocket

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #51 on: 06/25/2017 09:18 AM »
That was very brief. Is it removed now & disposed of?

Yes - it will be stowed back in the Dragon's trunk and will be deorbited.

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #52 on: 06/25/2017 09:31 AM »
Second deployment (after the seven day test)
« Last Edit: 06/26/2017 11:01 PM by centaurinasa »

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #53 on: 06/25/2017 09:34 AM »
Right now (after 2nd retraction) a third deployment !

http://www.ustream.tv/channel/live-iss-stream
« Last Edit: 06/25/2017 09:45 AM by centaurinasa »

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #54 on: 06/25/2017 09:40 AM »
Fully extended again...
« Last Edit: 06/25/2017 10:12 AM by centaurinasa »

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #55 on: 06/26/2017 06:49 PM »
From a more wide angle...

Offline SWGlassPit

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #56 on: 06/26/2017 10:12 PM »
Jettisoned as of about an hour ago.  They were unable to retract fully for stowage in the trunk.

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #57 on: 06/26/2017 10:32 PM »
Jettisoned as of about an hour ago.  They were unable to retract fully for stowage in the trunk.
"ROSA has been jettisoned by Dextre being commanded @csa_asc The roll up did not lock so plan was to jettison! Neat!"

https://twitter.com/Kam_Bahrami/status/879465833503870977
« Last Edit: 06/26/2017 10:41 PM by centaurinasa »

Offline centaurinasa

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #58 on: 06/26/2017 10:42 PM »
« Last Edit: 06/26/2017 10:51 PM by centaurinasa »

Offline russianhalo117

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #59 on: 06/26/2017 11:21 PM »
Jettisoned as of about an hour ago.  They were unable to retract fully for stowage in the trunk.
"ROSA has been jettisoned by Dextre being commanded @csa_asc The roll up did not lock so plan was to jettison! Neat!"

https://twitter.com/Kam_Bahrami/status/879465833503870977
It uses an ESPA interface to the FRAM with a springloaded Mk II Lightband (or similar) PAF securing the 2 together.
« Last Edit: 06/26/2017 11:22 PM by russianhalo117 »

Online Orbiter

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #60 on: 06/26/2017 11:39 PM »
Wonder how noticeable it'll be from the ground; solar panels can be quite reflective.
Attended space missions: STS-114, STS-124, STS-128, STS-135, Atlas V "Curiosity", Delta IV Heavy NROL-15, Atlas V MUOS-2, Delta IV Heavy NROL-37, SpaceX CRS-9, SpaceX JCSAT-16, Atlas V GOES-R.

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #61 on: 06/26/2017 11:53 PM »
Tracking should be fun - I wonder how fast it's spinning and if that'll change.
Pity it didn't lock, from a mission success POV, but certainly more interesting from a sighting POV.

Offline Hobbes-22

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #62 on: 06/27/2017 08:08 AM »
That seems an awfully large object to jettison. What's keeping ROSA from crashing into the station on the next orbit?

Offline Star One

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #63 on: 06/27/2017 09:27 AM »
How long until it deorbits as that seems to be an awfully large piece of space junk to be floating around up there near ISS?

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #64 on: 06/27/2017 10:42 AM »
Looking at the size, the width of the solar part of the array seems to be pretty close to 1m. This would, together with the images, put the length at around 10m, for about 10m^2, or 12kW of solar incident power.
Or perhaps 3000W.
This would conservatively place the weight in the 30kg range.
The area, assuming that it is randomly spinning and 10m^2 would be about 5m^2, so the effective sectional density is 6kg/m^2.

https://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/orbit/ISS/SVPOST.html gives the area of ISS as 17659ft^2, or ~2000m^2, and mass of 420000kg. Or 210kg/m^2.

ROSA decelerates at about 210/6 = 35 times the rate of ISS.
ISS started June at ~405.2km, and will end at 404.7 or so. A drop of 500/30 =16 meters a day, ~1m/orbit.

ROSA should lower in altitude by ~35m per orbit, 560m/day.
This would alter its period by one part in 10000 or so.

Handwaving stuff that I don't understand, this would lead to a miss by of the order of ~5s*8000m/s,  or 40km, after one day.

However, it's going to come uncomfortably close for a significant period. An old source says the collision avoidance box is 1km 'deep' from ISS towards earth, so to drop out of that box would take ROSA a couple of days.

It's at least possible that proper understanding of the drag model, and release time could mean that there is no risk to ISS.


500m a day, it could easily be a large fraction of a year before it reenters.

(Above orbital calculations according to Wil.E. Coyote's book of orbital mechanics, where all orbits are linear or square as convenient. I'd love someone to do it properly).
« Last Edit: 06/27/2017 11:03 AM by speedevil »

Offline Ictogan

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #65 on: 06/27/2017 12:52 PM »
Besides ROSA decaying much faster than ISS, it also seperated retrograde from ISS, meaning that it'll already start out in a slightly lower orbit. In the video it looks like ROSA seperated at ~1m/s. This would lower the semi-major axis of the array by about 1750m and reduce the orbital period by about 2 seconds. This means that on the next orbit it would arrive at the same spot as ISS about 2s later and given the ~7.7km/s speed of those orbits they'd be seperated by ~15km after just one orbit.

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #66 on: 06/27/2017 03:21 PM »
I had missed this most excellent video.


This goes into the deployment of the as-orbited config, as well as detailed design.
The truss expansion at high speed is neat.

Offline SWGlassPit

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #67 on: 06/27/2017 08:55 PM »
That seems an awfully large object to jettison. What's keeping ROSA from crashing into the station on the next orbit?

They jettison down and retrograde, which places it in a different orbit that won't intersect ISS's orbit as it decays.  It's the same approach they use for deploying cubesats.

Offline Lars-J

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Roll Out Solar Array (ROSA) headed to the ISS
« Reply #68 on: 06/28/2017 09:41 PM »
That seems an awfully large object to jettison. What's keeping ROSA from crashing into the station on the next orbit?

They jettison down and retrograde, which places it in a different orbit that won't intersect ISS's orbit as it decays.  It's the same approach they use for deploying cubesats.

And the reason Dragon and Cygnus approach from below - should they have a problem, they will naturally drift away from ISS with a minimal risk for recontact.
« Last Edit: 06/28/2017 10:45 PM by Lars-J »

Offline Lewis007

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Re: Roll Out Solar Array (ROSA) headed to the ISS
« Reply #69 on: 06/29/2017 06:56 AM »
Some pics released by NASA

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