Future Optical Space Telescopes - i.e. Hubble 2.0 ect

[a_langwich]

Secondly, Hubble has been popular in large part because of the spectacular images.  JWST simply won't provide that and public support for space astronomy will suffer.  That popularity allowed for NASA to do several servicing missions over the years.     

A great chunk of NASA's images, including Hubble images, that are shown today include a fair amount of information from outside the visible spectrum.  The gorgeous thing about Hubble images isn't a visible-spectrum lighting special effect, it's the wonderful structure and complexity and awe-inspiring scale of the universe.  It's entirely possible to generate spectacular visual images from JWST.  Parts of them ARE perfectly normal visible light images, just red-shifted by velocity. 

Part of the fascination behind the Hubble images is the science behind it, and at least the implication there are exciting new discoveries coming from it, rather than just a really hi-res version of the image you could get at a star-gazing party.  So just making a dedicated multi-billion star-party imager is likely to lose a little bit of the wonder. 

JWST overlaps Hubble capabilities, up into the visible spectrum.

I think a "Save the Hubble" mission could still be started today if the Scientific community would decide it was a priority.

That is precisely the problem:  it is NOT a _scientific_ priority.  For the limited amount of money they have, it's not on the priority list. 

But, if you think the popular support for Hubble-like images really is worth several billion dollars (as in the servicing missions), and won't be met by JWST or all the terrestrial big 'scopes for some reason, there's hope!  Simply raise the billion and a half or two in a foundation, and fund the launching of the second of the Hubble-sized mirrors NASA was given as a Hubble visible-light follow-on.  The first NASA hopes to use for WFIRST, but everything I've read suggests they don't have the money to use the second.  Or, if you think only a 4-5m size is the minimum for your tastes, fund that.  If people want it enough to put their money to it, then it's no problem.

I think there are plans afoot to do something like that (private consortia for space telescopes), on a smaller scale.  University consortia can raise on the order of a billion, so IF you can provide value on the level of a terrestrial Thirty Meter Telescope or the like, it can be privately done.  The terrestrial telescopes can have a much longer useful working life, but a space telescope offers much higher utilization rates during its life.  The terrestrial telescopes would be massively larger for the same budget, and more easily upgraded with more advanced adaptive optics and electronics, but the space telescope offers unique advantages of a tiny point spread function, the ability to look virtually anywhere in the sky at a time (if in a distant orbit), or stare for extended periods of time.  The space telescope will also require a ground terminal facility able to communicate with the observatory as many hours of the day as you wish to do science, which may imply ground stations spaced around the globe or an orbital relay facility.  Or you could try to pay NASA for DSN use, but it probably costs more than you could afford.

[Coastal Ron]

If the SLS is going to carry larger payloads, then a larger assembly facility will have to be built anyway. 

That's the point, it is a deal breaker.  There is no money for such payloads much the infrastructure upgrades.

A very good point, and one that SLS supporters don't seem to be aware of.

The SLS has an 8.4m diameter core, so any SLS-sized payloads are likely to be larger than what could fit in the current EELV sized launchers (~5m in diameter).

As you point out Jim, current payloads can be transported by road or by aircraft, but there are limits.  The U.S. Interstate freeway system limits payloads to 14-16 ft in total height, and a C-5 can only carry cargo that is up to 13.5ft in height.  Even the An-225, the largest cargo aircraft in the world, can only carry cargo that is up to 14ft in height.

So SLS-sized payloads will have to be built close to water transportation, which limits using existing facilities.  But even those existing facilities would have to create new infrastructure and tooling to handing SLS-sized payload manufacturing and testing.  Sure we have built rockets of that size before, but not payloads.

So there are costs associated with setting up a factory that has to be absorbed by the first product that is produced.  If more are produced the average costs can go down, but if we're talking about a single replacement for the Hubble, then the costs of building an HLV-sized monolithic platform could be very considerable.

[Jim]

and a C-5 can only carry cargo that is up to 13.5ft in height. 

There are two C-5's that can carry a 15' x 45' payloads

[Lee Jay]

If the SLS is going to carry larger payloads, then a larger assembly facility will have to be built anyway. 

That's the point, it is a deal breaker.  There is no money for such payloads much less the infrastructure upgrades.

The Cape/KSC would only need a processing facility.  The nation (meaning spacecraft  contractors and users) needs bigger manufacturing facilities like in Denver, Sunnyvale, Palo Alto, El Segundo, Renton, Redondo Beach, JPL, GSFC, etc.  And testing facilities and transportation systems to go between them.  Right now, everything is centered around 5m and still not many facilities can handle it.

tens of billions of dollars.

I don't know a lot about these facilities, but a quick search revealed this:

http://facilities.grc.nasa.gov/documents/TOPS/TopPB.pdf

It says the facility can handle 100 foot diameter by 122 foot long items.  That's 30.5m x 37.2m.  It's apparently located where such objects can be shipped by water transport.  I would think that they wouldn't have built such a large facility if such objects could not be built or shipped, but like I said I don't know a lot about it.

The entire site has a total current replacement value of more than $877.5 million, but that includes a lot of buildings and facilities having nothing to do with the SPF.

http://oig.nasa.gov/audits/reports/FY15/IG-15-014.pdf

I'm not sure if the facility would require some upgrades to vibration actuators, modal testing equipment and so forth (the acoustic test facility looks a little marginal at 11.4m by 14.5m 17.4m), or not, but it seems that at least some facilities exist to handle extremely large spacecraft.  The acoustic chamber is only listed as a $30M facility and the vibration facility is listed at $25M so maybe "tens of billions of dollars" is a little excessive even though it will include processes besides testing, including production.

[Jim]

It says the facility can handle 100 foot diameter by 122 foot long items.  That's 30.5m x 37.2m.  It's apparently located where such objects can be shipped by water transport.  I would think that they wouldn't have built such a large facility if such objects could not be built or shipped, but like I said I don't know a lot about it.

The SPF isn't a thermovac chamber.  Just a vacuum chamber (need better vacuum, sun lights and cryogenic cooling)  Water transport is no good if the origination facilities are not on water.  JWST is going to JSC vs GRC because of items like this

[llanitedave]

If the SLS is going to carry larger payloads, then a larger assembly facility will have to be built anyway. 

That's the point, it is a deal breaker.  There is no money for such payloads much the infrastructure upgrades.

A very good point, and one that SLS supporters don't seem to be aware of.

The SLS has an 8.4m diameter core, so any SLS-sized payloads are likely to be larger than what could fit in the current EELV sized launchers (~5m in diameter).

As you point out Jim, current payloads can be transported by road or by aircraft, but there are limits.  The U.S. Interstate freeway system limits payloads to 14-16 ft in total height, and a C-5 can only carry cargo that is up to 13.5ft in height.  Even the An-225, the largest cargo aircraft in the world, can only carry cargo that is up to 14ft in height.

So SLS-sized payloads will have to be built close to water transportation, which limits using existing facilities.  But even those existing facilities would have to create new infrastructure and tooling to handing SLS-sized payload manufacturing and testing.  Sure we have built rockets of that size before, but not payloads.

So there are costs associated with setting up a factory that has to be absorbed by the first product that is produced.  If more are produced the average costs can go down, but if we're talking about a single replacement for the Hubble, then the costs of building an HLV-sized monolithic platform could be very considerable.

Keep in mind, Ron, 8 meter monolithic telescope mirrors are cast and polished in Phoenix, Arizona, under the University of Arizona football stadium.  There's no water transport there.  These mirrors, fragile as they may seem, are placed in containers for transport, and are taken on public roads to remote mountaintops where they are surrounded by clean facilities that allow for their maintenance.


It's hard to believe that NASA can't afford the scale of facilities that other observatories, which are also operating on shoestring budgets, manage to provide.

[Lee Jay]

It says the facility can handle 100 foot diameter by 122 foot long items.  That's 30.5m x 37.2m.  It's apparently located where such objects can be shipped by water transport.  I would think that they wouldn't have built such a large facility if such objects could not be built or shipped, but like I said I don't know a lot about it.

The SPF isn't a thermovac chamber.

It is, sort of.

"The chamber can sustain a high vacuum (10-6 torr); provide an optically-tight, high-emissivity, thermal background environment of -250 °F to +140 °F within the 40-foot diameter by 40-foot high variable-geometry cryogenic shroud. "

http://facilities.grc.nasa.gov/spf/

I'm sure that building a bigger shroud, if necessary, wouldn't be an expensive thing to do in the context of a ~$10B telescope.

Water transport is no good if the origination facilities are not on water.

So you do final assembly somewhere other than where the components are manufactured, perhaps even at a facility like the SPF.

The point is, we have manufactured and transported very, very large items in this country (much larger than a hypothetical 8.4m monolithic telescope), and for a one-off thing like this, we could do it if we wanted to and without an investment that matches or exceeds the ~$10B cost of the item.  It wouldn't be cheap or easy, but it could be done and the transport and testing of the item wouldn't be a significant limiting factor.  It would cost some money and time, but it could be done, and for a lot less than "tens of billions" (excluding the spacecraft itself).

[Jim]

It is, sort of.

"The chamber can sustain a high vacuum (10-6 torr); provide an optically-tight, high-emissivity, thermal background environment of -250 °F to +140 °F within the 40-foot diameter by 40-foot high variable-geometry cryogenic shroud. "

Spacecraft are not using it because it not good enough and it is too far away from an airport.

[Jim]

Keep in mind, Ron, 8 meter monolithic telescope mirrors are cast and polished in Phoenix, Arizona, under the University of Arizona football stadium.  There's no water transport there.  These mirrors, fragile as they may seem, are placed in containers for transport, and are taken on public roads to remote mountaintops where they are surrounded by clean facilities that allow for their maintenance.

Wrong analogy.  Mirror has nothing do with it. An observatory is not a spacecraft manufacturing facility.   The issue is large spacecraft in general.  Handling just a mirror is not the same as handling a spacecraft and a bad example.   They are  two completely different tasks.    A mirror is small compared to a spacecraft.  It is transported  horizontally, and is just a wide load, which is easy.  It isn't transported in this orientation.

[Jim]

Which it would have to be as a telescope like this one.

[Jim]

And taking your SIRTF example, the secondary mirror and support would too tall to transport like your Arizona mirrors.

[Jim]

The point is, we have manufactured and transported very, very large items in this country itself).

But not kept them in a clean and conditioned environment at the same time.

 and for a one-off thing like this, we could do it if we wanted to and without an investment that matches or exceeds the ~$10B cost of the item.

That's the point, because isn't cheap or easy, it is a one-off thing.  So what else is SLS going to fly?

we could do it if we wanted to and without an investment that matches or exceeds the ~$10B cost of the item.  It wouldn't be cheap or easy, but it could be done and the transport and testing of the item wouldn't be a significant limiting factor.  It would cost some money and time, but it could be done, and for a lot less than "tens of billions" (excluding the spacecraft itself).

Where do you think most JWST's money is going?  Not the spacecraft.

[Mr. D]

If the SLS is going to carry larger payloads, then a larger assembly facility will have to be built anyway. 

That's the point, it is a deal breaker.  There is no money for such payloads much the infrastructure upgrades.

A very good point, and one that SLS supporters don't seem to be aware of.

The SLS has an 8.4m diameter core, so any SLS-sized payloads are likely to be larger than what could fit in the current EELV sized launchers (~5m in diameter).

As you point out Jim, current payloads can be transported by road or by aircraft, but there are limits.  The U.S. Interstate freeway system limits payloads to 14-16 ft in total height, and a C-5 can only carry cargo that is up to 13.5ft in height.  Even the An-225, the largest cargo aircraft in the world, can only carry cargo that is up to 14ft in height.

So SLS-sized payloads will have to be built close to water transportation, which limits using existing facilities.  But even those existing facilities would have to create new infrastructure and tooling to handing SLS-sized payload manufacturing and testing.  Sure we have built rockets of that size before, but not payloads.

So there are costs associated with setting up a factory that has to be absorbed by the first product that is produced.  If more are produced the average costs can go down, but if we're talking about a single replacement for the Hubble, then the costs of building an HLV-sized monolithic platform could be very considerable.

Keep in mind, Ron, 8 meter monolithic telescope mirrors are cast and polished in Phoenix, Arizona, under the University of Arizona football stadium.  There's no water transport there.  These mirrors, fragile as they may seem, are placed in containers for transport, and are taken on public roads to remote mountaintops where they are surrounded by clean facilities that allow for their maintenance.


It's hard to believe that NASA can't afford the scale of facilities that other observatories, which are also operating on shoestring budgets, manage to provide.

The Steward Observatory Mirror Lab, where the GMT and LSST mirrors are being manufactured, is in Tucson, not Phoenix. Also, since those mirrors are shipped in the horizontal position, all you need is a wide road, no serious constraints on height.

[jg]

And big mirrors have been shipped elsewhere in the world...  No particular thermal problems doing so.  And the mirrors are only in a really clean environment for aluminization.  Big telescopes have open truss supports.

[Coastal Ron]

Keep in mind, Ron, 8 meter monolithic telescope mirrors are cast and polished in Phoenix, Arizona, under the University of Arizona football stadium.  There's no water transport there.  These mirrors, fragile as they may seem, are placed in containers for transport, and are taken on public roads to remote mountaintops where they are surrounded by clean facilities that allow for their maintenance.

The Steward Observatory Mirror Lab, where the GMT and LSST mirrors are being manufactured, is in Tucson, not Phoenix. Also, since those mirrors are shipped in the horizontal position, all you need is a wide road, no serious constraints on height.

Thanks for pointing that out, and I was trying to highlight that point when I only referenced height restrictions, not width restrictions.  I guess I was too subtle.

While a component could be built anywhere and moved anywhere, the larger subassemblies and full up assemblies would likely be impacted by height restrictions.  Unless everyone is thinking the Hubble 2.0 is going to be less than 5m in length while being 8m in diameter...

[Coastal Ron]

It's hard to believe that NASA can't afford the scale of facilities that other observatories, which are also operating on shoestring budgets, manage to provide.

Operating in space requires different designs and materials, and the inability to access the instrument every day for solving minor problems means you have to spend a lot of time and money on making the instrument very dependable.

For instance, if a computer goes out on an observatory here on Earth you have a tech replace it that same day.  What are your options if that happens in space?  Well you don't want that to happen, so you spend $Millions on making very dependable computers.

Big difference.

[AnalogMan]

Concepts for a large space telescope assembled in stages are being thought about by some groups.  For example Northrop Grumman are studying an Evolved Space Telescope:

• 14m to 20m aperture
• three stage build
• initial stage & each increment forms a complete operational telescope
• 3-5 years between stage launches

A couple of recent 2-pagers from a COPAG call for white papers and a short AAS presentation are attached.  Rather light on any practical details other than telescope performance.

(COPAG = Cosmic Origins Program Analysis Group)

[Mr. D]

Concepts for a large space telescope assembled in stages are being thought about by some groups.  For example Northrop Grumman are studying an Evolved Space Telescope:

• 14m to 20m aperture
• three stage build
• initial stage & each increment forms a complete operational telescope
• 3-5 years between stage launches

A couple of recent 2-pagers from a COPAG call for white papers and a short AAS presentation are attached.  Rather light on any practical details other than telescope performance.

(COPAG = Cosmic Origins Program Analysis Group)

None of that includes a cost estimate, which should be a huge red flag. This all needs to fit in the Astrophysics theme's budget, and pass a Decadal Survey, so the cost is absolutely critical. A 20 m telescope on the ground is in the 1 G$ region, I'll decline to guess how much that would be in space.

Besides, if they actually intend to get the extra mirrors to be phased up (aligned coherently) with the rest, the initial instruments will either need to massively oversample the PSF in the early phases, or they'll need to be changed at each upgrade. Unless they just want to get them in an incoherent configuration, but why would anyone do that?

[Stormbringer]

DARPA gets in on the action:

http://www.spacedaily.com/reports/Brainstorm_with_DARPA_on_a_100x_Zoom_Lens_for_Seeing_Distant_Space_Objects_More_Clearly_999.html

[Star One]

DARPA gets in on the action:

http://www.spacedaily.com/reports/Brainstorm_with_DARPA_on_a_100x_Zoom_Lens_for_Seeing_Distant_Space_Objects_More_Clearly_999.html

That's a specific solution for a ground based telescope.