Author Topic: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)  (Read 121425 times)

Online russianhalo117

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #360 on: 01/09/2019 06:52 pm »
I do agree that WorldView-4 appears to be an ideal candidate for either MEV or Restore-L.  Getting into the history books as the first commercial satellite serviced by a commercial satellite servicing platform is worth the effort in my opinion.  The revenue earned from years of additional images only helps the case.

MEV1 is launching to the GEO belt this year to begin comsat life extension, same place MEV2 will be utilized. It's a hard sell to commission the construction and launch of an MEV to SSO unless you're preparing to buy the entire service life for your satellite... plane changes use up an atrocious amount of dV.
Long lead items for manufacture of the first 10 MEV's were signed for. While GEO and HEO were primary target audience there exists in design versions for all orbit types. The PFM of each version would take longer than all other FM built thereafter.
« Last Edit: 01/09/2019 10:08 pm by russianhalo117 »

Online Joseph Peterson

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #361 on: 01/09/2019 09:58 pm »
I do agree that WorldView-4 appears to be an ideal candidate for either MEV or Restore-L.  Getting into the history books as the first commercial satellite serviced by a commercial satellite servicing platform is worth the effort in my opinion.  The revenue earned from years of additional images only helps the case.

MEV1 is launching to the GEO belt this year to begin comsat life extension, same place MEV2 will be utilized. It's a hard sell to commission the construction and launch of an MEV to SSO unless you're preparing to buy the entire service life for your satellite... plane changes use up an atrocious amount of dV.
Long lead items for manufacture of the first 10 Mac's were signed for. While GEO and HEO were primary target audience there exists in design versions for all orbit types. The PFM of each version would take longer than all other FM built thereafter.

Is Mac's autocorrect changing MEV?

What do PFM and FM mean?

WorldView-4 is almost certainly a lease/buy/build an MEV/Restore-L to use exclusively for the next 5-10 years situation.  The servicing satellite's job would be to replace the precision point capability lost when the gyros failed.  This capability is needed hundreds(thousands?) of times a day.  Since the servicing satellite wouldn't be leaving WV-4 anytime soon, there are no plane changes to consider.

The real question is does servicing make sense from a business standpoint?  Things I don't know are whether the 80 cm Scout constellation images will be good enough to replace WV-4's 30 cm images, what the status of the next generation of ~30 cm imaging satellite development is, and the price and lead time of the servicing vehicle.
If ZBLAN can't pay for commercial stations, we'll just have to keep looking until we find other products that can combine to support humans earning a living in space.

Online russianhalo117

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #362 on: 01/09/2019 10:07 pm »
I do agree that WorldView-4 appears to be an ideal candidate for either MEV or Restore-L.  Getting into the history books as the first commercial satellite serviced by a commercial satellite servicing platform is worth the effort in my opinion.  The revenue earned from years of additional images only helps the case.

MEV1 is launching to the GEO belt this year to begin comsat life extension, same place MEV2 will be utilized. It's a hard sell to commission the construction and launch of an MEV to SSO unless you're preparing to buy the entire service life for your satellite... plane changes use up an atrocious amount of dV.
Long lead items for manufacture of the first 10 Mac's were signed for. While GEO and HEO were primary target audience there exists in design versions for all orbit types. The PFM of each version would take longer than all other FM built thereafter.

Is Mac's autocorrect changing MEV?

What do PFM and FM mean?

WorldView-4 is almost certainly a lease/buy/build an MEV/Restore-L to use exclusively for the next 5-10 years situation.  The servicing satellite's job would be to replace the precision point capability lost when the gyros failed.  This capability is needed hundreds(thousands?) of times a day.  Since the servicing satellite wouldn't be leaving WV-4 anytime soon, there are no plane changes to consider.

The real question is does servicing make sense from a business standpoint?  Things I don't know are whether the 80 cm Scout constellation images will be good enough to replace WV-4's 30 cm images, what the status of the next generation of ~30 cm imaging satellite development is, and the price and lead time of the servicing vehicle.
Yes. Autocorrect.
Prototype Flight Model
Flight Model
« Last Edit: 01/09/2019 10:10 pm by russianhalo117 »

Online Thorny

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #363 on: 01/09/2019 10:08 pm »
Is Mac's autocorrect changing MEV?

I just had to look it up on the Launch Schedules thread to see what all those MEVs in 2021 were.
MEV = Mission Extension Vehicle (prolong satellite life).

Offline jimvela

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #364 on: 01/09/2019 10:22 pm »
I'm not so sure that a servicing vehicle would be a good fit here, as an earth imaging spacecraft has to very carefully and closely control its pointing when imaging.  Without extensive flight software development, that isn't going to happen.  The spacecraft's FSW would have to be able to command the servicing vehicle to perform the same pointing that had previously been done under closed loop control of the existing ADCS software.

This isn't like a big GEO bird where you are essentially stationkeeping and in a relatively static attitude.

It's probably less expensive to replace the spacecraft with another one than to try and life extend this asset.

Offline Sam Ho

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #365 on: 01/10/2019 12:01 am »
WorldView-4 is almost certainly a lease/buy/build an MEV/Restore-L to use exclusively for the next 5-10 years situation.  The servicing satellite's job would be to replace the precision point capability lost when the gyros failed.  This capability is needed hundreds(thousands?) of times a day.  Since the servicing satellite wouldn't be leaving WV-4 anytime soon, there are no plane changes to consider.

The real question is does servicing make sense from a business standpoint?  Things I don't know are whether the 80 cm Scout constellation images will be good enough to replace WV-4's 30 cm images, what the status of the next generation of ~30 cm imaging satellite development is, and the price and lead time of the servicing vehicle.
It's probably less expensive to replace the spacecraft with another one than to try and life extend this asset.

The statement about the WV-4 failure is pretty clear about the business side: Maxar says WV-4 generates about $85M in annual revenue, of which they can offset $10-15M with other resources, and they are looking at a $155M writeoff if WV-4 is not recoverable.

DigitalGlobe is already building the next generation of 30cm imaging satellites: the WorldView Legion constellation, which is being built by sister company SSL, and has two Falcon 9 launches booked for 2021.

WorldView Legion is said to "double DigitalGlobe’s ability to collect the world’s highest resolution 30 cm satellite imagery and triple the capacity available over the highest-demand regions."  (This was written when both WV-3 and WV-4 were available, of course.)

http://investor.maxar.com/investor-news/press-release-details/2018/Maxar-Technologies-DigitalGlobe-Selects-SpaceX-to-Launch-its-Next-generation-WorldView-Legion-Satellites/default.aspx
https://calval.cr.usgs.gov/apps/sites/default/files/jacie/DigitalGlobeOverview_JACIE_9_19_17.pdf

Offline zubenelgenubi

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #366 on: 01/10/2019 03:06 am »
Another question would be:

Is US intelligence capability sufficiently damaged by the loss of WV-4 to justify a USG entity paying for, or subsidizing--as a test mission for a rescue satellite, a rescue of WV-4?

If not, then I suspect no.
***

<opinion>
As an interested American citizen, I'd say this circumstance would be an interesting engineering challenge, even if full capability were not restored.
</opinion>
« Last Edit: 01/10/2019 03:18 am by zubenelgenubi »
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Online Joseph Peterson

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #367 on: 01/10/2019 05:05 am »
I'm not so sure that a servicing vehicle would be a good fit here, as an earth imaging spacecraft has to very carefully and closely control its pointing when imaging.  Without extensive flight software development, that isn't going to happen.  The spacecraft's FSW would have to be able to command the servicing vehicle to perform the same pointing that had previously been done under closed loop control of the existing ADCS software.

This isn't like a big GEO bird where you are essentially stationkeeping and in a relatively static attitude.

It's probably less expensive to replace the spacecraft with another one than to try and life extend this asset.

We're commenting on NSF.  Why resort to probably when we can do a trade study?

From the financial information already posted we can extrapolate that every month a servicing satellite adds to WorldView-4's life is worth ~$6 million.  The Legion constellation should begin coming online in no less than 24 months.

What we are missing is how long it will take to bring the serviced WorldView-4 online and the cost.  If the job can be done in 9 months, there are $100 million reasons to get it done.  A job that takes 18 months can only recover $50 million in stranded value.  Can you add some perspective that allows me to put a time frame on how long you expect it will take to solve the issues you raise?
If ZBLAN can't pay for commercial stations, we'll just have to keep looking until we find other products that can combine to support humans earning a living in space.

Offline jongoff

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #368 on: 01/10/2019 06:27 am »
Is it poor taste to point out that this is exactly the kind of equipment failure we're trying to make a thing of the past by our MagTag plug and play interfaces?
How well does this work when (as in this case) the vehicle has lost some degree of attitude control?

(or is this a "only mostly dead" situation where the spacecraft can't do its job but can hold itself still enough to be grabbed by a servicing spacecraft?)

Ideally for a spacecraft designed with servicing in mind, you'd have a grapple fixture of some sort (we like our DogTags) in addition to one or more modular plug and play port(s) like MagTags. The DogTags would enable capture even if tumbling. After you've detumbled, you'd then attach MagTags.

In this case I don't know that the spacecraft is tumbling though. Not sure.

~Jon


Offline zubenelgenubi

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #369 on: 01/10/2019 07:14 am »
<snip>
In this case I don't know that the spacecraft is tumbling though. Not sure.

~Jon

If we don't hear from "official" sources, we should hear from the amateur satellite observers--if it's tumbling, the satellite's magnitude will vary.  If there is periodicity, the rotation period or periods could be deduced.
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Offline Star One

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #370 on: 01/10/2019 05:53 pm »
This hasn’t been posted in this thread.

Fixing broken satellites in space could save companies big money

Quote
Several aerospace startups are trying to figure out how to repair satellites, working on technologies that could someday provide a solution for DigitalGlobe and Maxar. These companies propose to build spacecraft that would stay in space and rendezvous with failed satellites. Some will aim to get rid of them by dragging them down closer to Earth so they fall out of orbit and burn up in our planet’s atmosphere. Others suggest another solution: adding replacement parts to the craft so that it can continue working as it was intended.

Quote
Another big problem is accessibility. The satellites that go into space right now aren’t exactly built to be grabbed. WorldView-4 is considered “non-cooperative,” meaning it doesn’t have any features that would allow another spacecraft to dock to it. Many of the satellite servicing companies in the works right now are trying to come up with some kind of standardized interface to solve this problem. The idea is that, in the future, all satellites would be built with an interface that would include some kind of grappling feature.

Offline jongoff

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #371 on: 01/10/2019 06:30 pm »
This hasn’t been posted in this thread.

Fixing broken satellites in space could save companies big money

Quote
Several aerospace startups are trying to figure out how to repair satellites, working on technologies that could someday provide a solution for DigitalGlobe and Maxar. These companies propose to build spacecraft that would stay in space and rendezvous with failed satellites. Some will aim to get rid of them by dragging them down closer to Earth so they fall out of orbit and burn up in our planet’s atmosphere. Others suggest another solution: adding replacement parts to the craft so that it can continue working as it was intended.

Quote
Another big problem is accessibility. The satellites that go into space right now aren’t exactly built to be grabbed. WorldView-4 is considered “non-cooperative,” meaning it doesn’t have any features that would allow another spacecraft to dock to it. Many of the satellite servicing companies in the works right now are trying to come up with some kind of standardized interface to solve this problem. The idea is that, in the future, all satellites would be built with an interface that would include some kind of grappling feature.

Loren did a great job with the article (I'm obviously biased). I should say though that it is possible to capture and service non-cooperative satellites. It just tends to be much, much harder. Plugging in a replacement CMG if the satellite had a DogTag and MagTag would probably be something that could be done for <<$10M. Trying to grapple the satellite, attach a structure with a a CMG (and other support hardware) on it, and get that CMG to talk with the spacecraft well enough to restore pointing capabilities is probably much more expensive, though I think it's within the realm of possibility. To be honest, I've been thinking about this all night, and I can see technical solutions to most of the problems that aren't implausibly hard.

The biggest question is really the business one -- would Maxar be willing to sign a contract with someone to buy the satellite back if functionality could be restored? And if so, could you make the business number close? I'm intrigued.

~Jon

Online Joseph Peterson

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #372 on: 01/10/2019 10:01 pm »

Loren did a great job with the article (I'm obviously biased). I should say though that it is possible to capture and service non-cooperative satellites. It just tends to be much, much harder. Plugging in a replacement CMG if the satellite had a DogTag and MagTag would probably be something that could be done for <<$10M. Trying to grapple the satellite, attach a structure with a a CMG (and other support hardware) on it, and get that CMG to talk with the spacecraft well enough to restore pointing capabilities is probably much more expensive, though I think it's within the realm of possibility. To be honest, I've been thinking about this all night, and I can see technical solutions to most of the problems that aren't implausibly hard.

The biggest question is really the business one -- would Maxar be willing to sign a contract with someone to buy the satellite back if functionality could be restored? And if so, could you make the business number close? I'm intrigued.

~Jon

Jon,

Do you have a rough mass estimate for the solutions you've considered?

What I really want to know is, "Is Electron good enough?"  $5 million in launch costs makes for a far better business case than $60 million.
If ZBLAN can't pay for commercial stations, we'll just have to keep looking until we find other products that can combine to support humans earning a living in space.

Offline John Santos

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #373 on: 01/10/2019 10:21 pm »
Is it poor taste to point out that this is exactly the kind of equipment failure we're trying to make a thing of the past by our MagTag plug and play interfaces?
How well does this work when (as in this case) the vehicle has lost some degree of attitude control?

(or is this a "only mostly dead" situation where the spacecraft can't do its job but can hold itself still enough to be grabbed by a servicing spacecraft?)

Ideally for a spacecraft designed with servicing in mind, you'd have a grapple fixture of some sort (we like our DogTags) in addition to one or more modular plug and play port(s) like MagTags. The DogTags would enable capture even if tumbling. After you've detumbled, you'd then attach MagTags.

In this case I don't know that the spacecraft is tumbling though. Not sure.

~Jon
Probably off-topic, but NROL-71 (currently waiting on the pad at VAFB) has dog tags on its mission patch...  I wonder if it's designed for servicing.

Online LouScheffer

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #374 on: 01/10/2019 11:51 pm »
Quote from: Joseph Peterson link=topic[quote
January 07, 2019

https://spacenews.com/digitalglobe-loses-worldview-4-satellite-to-gyro-failure/

I'd love to know what bearing Lockmart might have used on a satellite launched in 2016.  The now-known welding issue with metal bearings is easy enough to engineer around.  Is there any chance this loss is that simple?
It was apparently constructed in 2012, then spent years in storage.   This was well before the arcing problem was understood, so it almost surely has metal bearings.

Also, CMGs put larger forces on their bearings than reaction wheels.  I don't know if they switched to ceramic balls in the ball bearings, as some reaction wheels have done.  (At least one small-sat CMG prototype used ceramic balls, but for lubrication reasons, not for preventing arcing damage.)

Offline jongoff

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #375 on: 01/11/2019 04:39 am »
Is it poor taste to point out that this is exactly the kind of equipment failure we're trying to make a thing of the past by our MagTag plug and play interfaces?
How well does this work when (as in this case) the vehicle has lost some degree of attitude control?

(or is this a "only mostly dead" situation where the spacecraft can't do its job but can hold itself still enough to be grabbed by a servicing spacecraft?)

Ideally for a spacecraft designed with servicing in mind, you'd have a grapple fixture of some sort (we like our DogTags) in addition to one or more modular plug and play port(s) like MagTags. The DogTags would enable capture even if tumbling. After you've detumbled, you'd then attach MagTags.

In this case I don't know that the spacecraft is tumbling though. Not sure.

~Jon
Probably off-topic, but NROL-71 (currently waiting on the pad at VAFB) has dog tags on its mission patch...  I wonder if it's designed for servicing.


When I talk about DogTags (as opposed to dog tags), I'm talking about a grappling fixture design Altius has been working on. I wish they had them on board, but would probably know if they did... :-)

~Jon
« Last Edit: 01/11/2019 04:40 am by jongoff »

Offline jongoff

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #376 on: 01/11/2019 04:42 am »
Do you have a rough mass estimate for the solutions you've considered?

What I really want to know is, "Is Electron good enough?"  $5 million in launch costs makes for a far better business case than $60 million.

Joseph,

I don't have enough details yet to know if something the size of our Bulldog could do the job, of if you would need something bigger/more complex. Bulldog is <100kg, so it would fit easily on an Electron launch, and yeah it would make zero sense to fly it on a bigger rocket unless you were ridesharing.

~Jon

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #377 on: 01/12/2019 06:54 pm »
I don't believe Worldview-4 can be saved by satellite servicing. If you attach a mission extension vehicle to it, it will need to be able to slew the satellite very fast to compensate for the lost CMG, because such observation satellites need high agility to be productive. But you need to attach the MEV to something that can withstand a high torque, without the MEV+satellite coupling introducing new vibration modes that would destroy the image quality. Plus the MEV itself has to be designed to endure high slew rates, but MEV are designed for GEO where the design rotation rate is to spin 360° in 24h, not in tens of seconds.

Offline jongoff

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Re: WorldView-4 - Atlas V 401 - November 11, 2016 (18:30 UTC)
« Reply #378 on: 01/12/2019 08:25 pm »
I don't believe Worldview-4 can be saved by satellite servicing. If you attach a mission extension vehicle to it, it will need to be able to slew the satellite very fast to compensate for the lost CMG, because such observation satellites need high agility to be productive. But you need to attach the MEV to something that can withstand a high torque, without the MEV+satellite coupling introducing new vibration modes that would destroy the image quality. Plus the MEV itself has to be designed to endure high slew rates, but MEV are designed for GEO where the design rotation rate is to spin 360° in 24h, not in tens of seconds.

I wasn't suggesting using the MEV--I agree that would almost certainly not work, and I agree that the stiffness of the connection (and how well you can communicate between the "CMG replacement solution" and the WV-4 spacecraft) are going to be critical. There's a real chance it would be impossible to make work, but so far I haven't seen enough details to write off the possibility--from a technical standpoint. I can see some ways it could potentially work, depending on some technical details I'm not yet privy to.

~Jon

Tags: wv-4