Crew Dragon or Orion to Hubble for CMG Replacement?

[MATTBLAK]

What about a crew Dragon with 3x crew (2x experienced Shuttle-Hubble Astros) and CMG's in the trunk?! Two of the Astronauts could perform a pair of EVAs to install new gyros and batteries and the other Astro would be there to assist them in suiting up and 'flying' the Dragon.

Can the Dragon be configured to do multiple EVAs? If the Falcon 9 is fully expended and launched to the 28.5 degree inclination orbit that Hubble is in: would the Dragon have enough delta-v to reach the telescope? Can a set of gyros and batteries fit in the Dragon's cargo trunk? I'd love to see someone do a feasibility study on a mission like this!! And could the Dragon dock with the docking unit that was left on the Hubble by the STS-125 crew? Could EVA's be done on the telescope without an RMS system? Or could the crew suffice with the pole system that was being looked at for the now abandoned Asteroid Rendezvous mission?

Or would this be a mission better suited to an Orion, launched on a Delta IV-Heavy, now that the ICPS stage is going to be 'man rated'?

Are there any Astronauts who repaired Hubble still on the active duty roster? How feasible would it be to reinstate 'Hubble Astronauts' who would still pass the physical or have only recently retired? Also: I know that it might be better to plow the mission's money into new space telescopes, or dock a 'stability' CMG control/command module to the base of Hubble...

...I'm only pondering this concept as a 'face saving' idea if - God fervently forbid - if the James Webb ends up in the drink after launch, or fails to deploy.

[Lars-J]

Dragon cannot support an EVA. It would require an external airlock module.

Orion can, but that's because it is designed to be able to do it, which means that the internals are fully vacuum rated (electronics) and that the entire cabin can be depressurized and pressurized again (and again?). This requires a lot of consumables. The Orion spacesuits are also designed to support it, unlike the Dragon IVA suits.

[woods170]

What about a crew Dragon with 3x crew (2x experienced Shuttle-Hubble Astros) and CMG's in the trunk?! Two of the Astronauts could perform a pair of EVAs to install new gyros and batteries and the other Astro would be there to assist them in suiting up and 'flying' the Dragon.

Can the Dragon be configured to do multiple EVAs? If the Falcon 9 is fully expended and launched to the 28.5 degree inclination orbit that Hubble is in: would the Dragon have enough delta-v to reach the telescope? Can a set of gyros and batteries fit in the Dragon's cargo trunk? I'd love to see someone do a feasibility study on a mission like this!! And could the Dragon dock with the docking unit that was left on the Hubble by the STS-125 crew? Could EVA's be done on the telescope without an RMS system? Or could the crew suffice with the pole system that was being looked at for the now abandoned Asteroid Rendezvous mission?

Or would this be a mission better suited to an Orion, launched on a Delta IV-Heavy, now that the ICPS stage is going to be 'man rated'?

Are there any Astronauts who repaired Hubble still on the active duty roster? How feasible would it be to reinstate 'Hubble Astronauts' who would still pass the physical or have only recently retired? Also: I know that it might be better to plow the mission's money into new space telescopes, or dock a 'stability' CMG control/command module to the base of Hubble...

...I'm only pondering this concept as a 'face saving' idea if - God fervently forbid - if the James Webb ends up in the drink after launch, or fails to deploy.

I read about 20 non-starters in your post, all of which will cost considerable money to solve.
IMO not worth the effort given Hubble's age and the fact that JWST will be online a few years from now.

Also, if the current CMG cannot be recovered science operations on HST will continue under a well-developed "plan B".

Face it folks: there will come a day that Hubble "dies" in orbit. With the Shuttle gone there is not all that much that can be done to prevent it. When the day comes we shouldn't mourn about the loss but celebrate the huge achievement that Hubble (still) is. And then move on to the next great adventure.

If, God forbid, JWST goes into the drink or fails to deploy, the astronomers will simply have to do without an orbiting telescope for the next decade (at least).
Then again, that would finally give them a chance to really start using those fine Earth-bound systems they have been deploying world-wide for the past 2 decades.
All is not lost when Hubble dies and a next-generation system is not (yet) online.

[MATTBLAK]

I already knew some of the answers, but not to all my questions. And at this point, I do not have much faith in Webb getting to where it's going and safely deploying with it's nearly insane 'Rube Goldberg' mechanisms and procedures. If after so many billions spent it ends up a lemon; it will make the 'Mister Magoo' jokes about Hubble in the early '90s look like a picnic.

**But I'll go on record as saying I will be thoroughly delighted to be wrong about Webb. Thoroughly.

If Hubble lost too many more gyros; would it be better than a manned mission to send up a propulsion and stability 'Bus' that could dock to the telescope and keep it stable for a few more years? Then, using storable propellant propulsion; finally send it to it's doom.

The above scenario might be a good 'Plan C'.

[ncb1397]

If, God forbid, JWST goes into the drink or fails to deploy, the astronomers will simply have to do without an orbiting telescope for the next decade (at least).

Well, other than Swift, Fermi, Chandra, NuSTAR, IRIS, TESS, Spitzer and WISE (and that is only the U.S. ones). And it isn't completely impossible that WFIRST gets launched around 2025 or so, especially if tons of budget money gets freed up from no Hubble and no JWST.

[MATTBLAK]

I need to point out: I am not actually, physically advocating one more manned mission to Hubble. The thread was started to explore the concept of such missions with the obvious historical example of Hubble that we're all familiar with. Even a robotic, manipulated mission from the ground would cost a lot of money to do. But being that it was once(?) advocated that a Hubble de-orbit robotic mission need one day be mounted, I have become intrigued by the possibility of upgrading that to a stability and de-orbit bus to give Hubble a few (3, 4 or 5 years?) extra life till another major systems flaw or the batteries die...

[IRobot]

How much would a Museum pay for the Hubble? Would a BFS mission to bring it back be viable, money wise?

[MATTBLAK]

Unknown at this point. Hope it could come to pass.

[Swedish chef]

According to this op-ed there should exist a small study or at least some power point slides about boosting the orbit of Hubble and replacing the gyroscopes.

https://spacenews.com/op-ed-a-not-so-final-servicing-mission/

SpaceX, manufacturer of both the Dragon and the Falcon 9, did a very preliminary, informal study of using Crew Dragon with a robot arm to deorbit Hubble, or to repair and reboost the telescope. This was part of a wider SpaceX PowerPoint presentation on using Crew Dragon to service satellites, publicly released in March 2010 just before the first Falcon 9 launch.

[nacnud]

Could you steer Hubble with external gyros attached to the LIDS mounted on it? You might not get very good slew rates but It's much easier that replacing the internal gyros.

[Swedish chef]

I found this slide that might be interesting since it shows what module needs to replaced and where they reside inside Hubble. The gyroscopes are packed in pairs inside a module that is called Rate Sensor Unit.

Source for the slide
https://slideplayer.com/slide/8528747/

[IRobot]

Could you steer Hubble with external gyros attached to the LIDS mounted on it? You might not get very good slew rates but It's much easier that replacing the internal gyros.

How would they communicate with the internal computer? I seriously doubt that the Hubble has enough modularity to accomodate this external input. How would you power them?
At best you would still need to connect multiple cables, which means opening it up, which would probably mean that a direct gyro replacement would be easier.

[speedevil]

Could you steer Hubble with external gyros attached to the LIDS mounted on it? You might not get very good slew rates but It's much easier that replacing the internal gyros.

How would they communicate with the internal computer? I seriously doubt that the Hubble has enough modularity to accomodate this external input. How would you power them?
At best you would still need to connect multiple cables, which means opening it up, which would probably mean that a direct gyro replacement would be easier.

In principle, solar, and reception of any of the existing antennas. While obviously not pointed at the LIDS mount, they can be received just fine at ~5m distance.

(yes, solar adds additional observing constraints)

[Zed_Noir]

Really don't think a HST rescue mission with a single Dragon is that doable.

But maybe adding a modified Cygnus with a 3 segment pressurized module to the mission might work. Using the Cygnus PM basically as an airlock with external racks for mounting manipulator arms, additional propellant storage and holding bins for the gyros along with external EVA helpful attachments. There is no cargo inside the Cygnus PM.

The idea is to launched the Cygnus first then the Dragon later to docked with the Cygnus. The vehicle stack will then go to the HST using the Cygnus's propulsion with the additional propellants. Grapple the HST and replace the hardware. The Dragon then returns the crew back to Earth with almost a full propellant load remaining aboard.

Of course it would take time to get the replacement hardware and training the service crew of maybe 3 astronauts.

[IRobot]

Could you steer Hubble with external gyros attached to the LIDS mounted on it? You might not get very good slew rates but It's much easier that replacing the internal gyros.

How would they communicate with the internal computer? I seriously doubt that the Hubble has enough modularity to accomodate this external input. How would you power them?
At best you would still need to connect multiple cables, which means opening it up, which would probably mean that a direct gyro replacement would be easier.

In principle, solar, and reception of any of the existing antennas. While obviously not pointed at the LIDS mount, they can be received just fine at ~5m distance.

(yes, solar adds additional observing constraints)

Have some doubts that the communication system is prepared for real time feed from the gyros. Unsure about reaction time requirements.

[Alexphysics]

There are currently no simple ways of doing this and any complex way of doing it means lots of money that don't exist. Also, don't point to JWST as Hubble's successor because it is not. Once Hubble goes away there will be no other telescope like this one. There are others, that's totally right, but they observe in different wavelengths and the only closest one to Hubble in those terms will be WFIRST if it ever gets built and launched.

[MATTBLAK]

I remember that there were two NRO 'Hubble class' telescopes that were 'gifted' to NASA. I've just Googled about them but only get articles with vague sets of details about them. Are one or both of these going to be recycled into space telescopes? Could one of them be a better platform for the WFIRST concept?

[kevinof]

Love this idea. Big fan of Cygnus as a "truck" and combining it with Dragon 2 like this is a great idea.

Really don't think a HST rescue mission with a single Dragon is that doable.

But maybe adding a modified Cygnus with a 3 segment pressurized module to the mission might work. Using the Cygnus PM basically as an airlock with external racks for mounting manipulator arms, additional propellant storage and holding bins for the gyros along with external EVA helpful attachments. There is no cargo inside the Cygnus PM.

The idea is to launched the Cygnus first then the Dragon later to docked with the Cygnus. The vehicle stack will then go to the HST using the Cygnus's propulsion with the additional propellants. Grapple the HST and replace the hardware. The Dragon then returns the crew back to Earth with almost a full propellant load remaining aboard.

Of course it would take time to get the replacement hardware and training the service crew of maybe 3 astronauts.

[as58]

I remember that there were two NRO 'Hubble class' telescopes that were 'gifted' to NASA. I've just Googled about them but only get articles with vague sets of details about them. Are one or both of these going to be recycled into space telescopes? Could one of them be a better platform for the WFIRST concept?

One of them is the platform for WFIRST.

[MATTBLAK]

Love this idea. Big fan of Cygnus as a "truck" and combining it with Dragon 2 like this is a great idea.

Really don't think a HST rescue mission with a single Dragon is that doable.

But maybe adding a modified Cygnus with a 3 segment pressurized module to the mission might work. Using the Cygnus PM basically as an airlock with external racks for mounting manipulator arms, additional propellant storage and holding bins for the gyros along with external EVA helpful attachments. There is no cargo inside the Cygnus PM.

The idea is to launched the Cygnus first then the Dragon later to docked with the Cygnus. The vehicle stack will then go to the HST using the Cygnus's propulsion with the additional propellants. Grapple the HST and replace the hardware. The Dragon then returns the crew back to Earth with almost a full propellant load remaining aboard.

Of course it would take time to get the replacement hardware and training the service crew of maybe 3 astronauts.

I've often thought that a Crew Dragon and a three segment Cygnus might be a great pair of vehicles to do the 'Inspiration Mars' style mission, if a suitable life support system could be found! A two segment Cygnus for one Astronaut and a three-segment for two Astros. But that's a digression here and is worthy of it's own thread...

[Swedish chef]

Scott Manley mentioned an interesting idea, send up a rocket and change the orbit. After that the astronauts on ISS could service the telescope.

[Hauerg]

WHICH rocket?

[speedevil]

WHICH rocket?

A Big one.
Neglecting the other issues, and altitude, because it can be easily neglected, HST is at 28.5 degrees, ISS 51.6.
To change inclination by 28 degrees in LEO needs around 3.7km/s.
If your rocket weighs a couple of tons, you end up (if hypergolic) needing around 40 tons, or with methalox, 25 tons of propellant. (neglecting initial rendevous propellant)

If you use something based off a commercial comsat, with electric propulsion, likely you end up with around 18 tons or so total launch mass.

A side-benefit from this is you've probably come pretty close to developing something to push modules electrically to LOP-G.

[envy887]

WHICH rocket?

A Big one.
Neglecting the other issues, and altitude, because it can be easily neglected, HST is at 28.5 degrees, ISS 51.6.
To change inclination by 28 degrees in LEO needs around 3.7km/s.
If your rocket weighs a couple of tons, you end up (if hypergolic) needing around 40 tons, or with methalox, 25 tons of propellant. (neglecting initial rendevous propellant)

If you use something based off a commercial comsat, with electric propulsion, likely you end up with around 18 tons or so total launch mass.

A side-benefit from this is you've probably come pretty close to developing something to push modules electrically to LOP-G.

Either Delta IV Heavy or a fully expended Falcon Heavy should be able to do that, assuming it can rendezvous and burn in less time than a coast to GEO.

[whitelancer64]

I remember that there were two NRO 'Hubble class' telescopes that were 'gifted' to NASA. I've just Googled about them but only get articles with vague sets of details about them. Are one or both of these going to be recycled into space telescopes? Could one of them be a better platform for the WFIRST concept?

Just as a general FYI, the NRO did not donate telescopes, but mirror sets. They are a primary and secondary mirror set and the structure that holds them, and nothing else. They are not complete telescopes.

WFIRST was re-scoped to use one of the NRO mirror sets. The NRO mirrors are twice the diameter of the original WFIRST proposal. that's why it nearly doubled in cost.

There are numerous proposals for the second set, none of which have been accepted yet.

[pb2000]

If NASA offered a $200m+ bounty, supplied the spare parts and just told any interested parties to call before grappling, then it might work. If NASA actually wanted to be involved... nah.

[Jim]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

[MATTBLAK]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

Yes. Probably best to keep Astronauts out of the picture at this stage of the telescope's career. Jim for the Win. Time to lock the thread?

[Coastal Ron]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

Very elegant idea.

And this looks like an opportunity for one of my favorite spacecraft, the Orbital/Orbital ATK/Northrop Grumman Innovation Systems Cygnus (whew!).

Just put a docking and non-propulsive attitude control system package in a compact module in place of the normal Pressurized Cargo Module (PCM), and let the Service Module (SM) do the work of moving things around.

Maybe DARPA would like to help fund such an effort to see if it could help extend the useful lives of other government assets in space?

[MATTBLAK]

Although I did mention the overall idea earlier in the thread; thanks for the specific vehicle idea. Increasing the Cygnus propellant load to give this Hubble life extension at least a couple years would make the cost worth it. I hope they can make the vehicle somehow talk to the Hubble's control system to allow the Cygnus attitude control authority.

[Cherokee43v6]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

Very elegant idea.

Not to mention that should the disposal option be chosen, that the 'reboost module' could serve in that capacity.

[woods170]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

You left out a tiny little detail: the need to disable Hubble's own attitude control system to allow the ACS of the docked spacecraft bus to take over. Which means completely changing the way the Hubble computers operate the telescope.

[Oersted]

Dragon cannot support an EVA. It would require an external airlock module.

Ah, but we'd just need to take a page out of the Soviet playbook and add an inflatable airlock. I'm sure Bigelow can come up with something...

[nacnud]

Dragon cannot support an EVA. It would require an external airlock module.

Ah, but we'd just need to take a page out of the Soviet playbook and add an inflatable airlock. I'm sure Bigelow can come up with something...

And some way to get it from the trunk to Dragons docking port.

[octavo]

Dragon cannot support an EVA. It would require an external airlock module.

Ah, but we'd just need to take a page out of the Soviet playbook and add an inflatable airlock. I'm sure Bigelow can come up with something...

And some way to get it from the trunk to Dragons docking port.

*** dons fire-proof suit ***

While we're about it, why not just slap a Raptor US on F9 to increase performance? :p

[woods170]

Dragon cannot support an EVA. It would require an external airlock module.

Ah, but we'd just need to take a page out of the Soviet playbook and add an inflatable airlock. I'm sure Bigelow can come up with something...

And some way to get it from the trunk to Dragons docking port.

*** dons fire-proof suit ***

While we're about it, why not just slap a Raptor US on F9 to increase performance? :p

Now where did I leave my flame-thrower?

Let's just not go down the "Raptor upper stage"-path again. Or we will invoke the wrath of Lar.

[nacnud]

Dragon cannot support an EVA. It would require an external airlock module.

Ah, but we'd just need to take a page out of the Soviet playbook and add an inflatable airlock. I'm sure Bigelow can come up with something...

And some way to get it from the trunk to Dragons docking port.

*** dons fire-proof suit ***

While we're about it, why not just slap a Raptor US on F9 to increase performance? :p

Now where did I leave my flame-thrower?

Let's just not go down the "Raptor upper stage"-path again. Or we will invoke the wrath of Lar.

Exactly

[Bananas_on_Mars]

Ok, what's so special about hubble that we can't simply build a replacement? Not with all new and super fancy stuff like the want with WFIRST, but with the technology level Hubble has now? Hubble has been launched 30 years ago, upgraded the last time almost 10 years ago.
Why isn't it possible to build something based on a commercial spacecraft bus, for let's say 500 mio. $ that's new and shiny and has the same capabilities of 30-10 year old hardware?

[Rocket Science]

Ok, what's so special about hubble that we can't simply build a replacement? Not with all new and super fancy stuff like the want with WFIRST, but with the technology level Hubble has now? Hubble has been launched 30 years ago, upgraded the last time almost 10 years ago.
Why isn't it possible to build something based on a commercial spacecraft bus, for let's say 500 mio. $ that's new and shiny and has the same capabilities of 30-10 year old hardware?

Sure, we'll just manage the program along the lines of the Webb Space Telescope...

[Robotbeat]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

You left out a tiny little detail: the need to disable Hubble's own attitude control system to allow the ACS of the docked spacecraft bus to take over. Which means completely changing the way the Hubble computers operate the telescope.

Update the firmware.

[RonM]

Ok, what's so special about hubble that we can't simply build a replacement? Not with all new and super fancy stuff like the want with WFIRST, but with the technology level Hubble has now? Hubble has been launched 30 years ago, upgraded the last time almost 10 years ago.
Why isn't it possible to build something based on a commercial spacecraft bus, for let's say 500 mio. $ that's new and shiny and has the same capabilities of 30-10 year old hardware?

Sure, we'll just manage the program along the lines of the Webb Space Telescope...

The problem with Webb is all the new technology. Building a Hubble replacement with "off the shelf" tech would be reasonable.

[Jim]

Why isn't it possible to build something based on a commercial spacecraft bus,

Commercial spacecraft buses are not designed for missions like HST.

And still there is the telescope part.

[Coastal Ron]

Why isn't it possible to build something based on a commercial spacecraft bus,

Commercial spacecraft buses are not designed for missions like HST.

OK, but what would be? And even if they are not designed for such missions, what do they lack for such missions?

And still there is the telescope part.

In what way?

And not that I think Congress would fund such an effort, but it is an interesting thought experiment given the newer capabilities we have today and in the near future.

[Lar]

(mod) We got a complaint that this discussion isn't SpaceX any more. The irony of that complaint wasn't lost on me... but let's try to stay marginally focused on the topic. A Raptor upper stage, for example, would be off topic.  And stop laughing.

(fan) Also, Rocket parts are not LEGO elements, to be put together in whatever way one can imagine. Doesn't work that way. A D2 mission would take a lot of engineering and be diversionary. When the last HST science (positioning and desaturating) gyro gives out, safe HST and build a fixture to stow it inside a BFS and bring it home. The safe mode gyros should have some considerable life remaining presumably.

[LouScheffer]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

You left out a tiny little detail: the need to disable Hubble's own attitude control system to allow the ACS of the docked spacecraft bus to take over. Which means completely changing the way the Hubble computers operate the telescope.

Without knowing how it works, I'd guess disabling Hubble's own pointing gyros and actuators and substituting others is not hard. 

To measure its pointing, Hubble needs to measure the state of the gyros, and convert this to angular pointing.   Presumably this is a matrix operation that is in software, since it needs to work with any 3 of the 6 gyros.

Likewise, when Hubble wants to point, it sends commands to the reaction wheels to change speed.  This should also be a matrix operation that projects the desired change in angular state onto the axes of the active reaction wheels.  It is also presumably in software since they need to be able to use any big-enough subset of the wheels.

Assuming the replacement ACS has its own gyros, or its own reaction wheels, or both, then Hubble needs to power down the corresponding internal hardware, then use modified matrix values when reading the new gyros or driving the new reaction wheels.  My main question would be if there is a path with high enough bandwidth from the pointing measurement and computation units in the Hubble to the added module.

[speedevil]

My main question would be if there is a path with high enough bandwidth from the pointing measurement and computation units in the Hubble to the added module.

As mentioned above, the radios can be used.
Any radio capable of being received at distance can at much lower power (if this is an option) be received by something a few meters away, even if not pointed correctly.
If not capable of reduced power, the transmitter dishes can be pointed into space.

Basically, the payload just pretends to be one of the TDRS network. The only question would be if the latency is low enough.

[Mark Lattimer]

You merely have to expand Crew Dragon's mission envelope somewhat to include servicing Hubble's cousins, the NRO's KH-11 satellites, and your funding problems are solved.   

[Jim]

You merely have to expand Crew Dragon's mission envelope somewhat to include servicing Hubble's cousins, the NRO's KH-11 satellites, and your funding problems are solved.   

That is nonsense

[Jim]

OK, but what would be? And even if they are not designed for such missions, what do they lack for such missions?

Propellantless attitude control system.  Precise pointing.   Large payload capability. 

Also, most commercial buses are just designed to point at the earth.

[vt_hokie]

I think it needs to be clarified that there are rate sensing gyros, and momentum/reaction wheels.  What is replaceable on Hubble is the former, but I don't know if the reaction wheels are.  It also uses replaceable magnetic torquers on the arrays for pointing.  Corrections and clarifications welcome of course!

[Halidon]

OK, but what would be? And even if they are not designed for such missions, what do they lack for such missions?

Propellantless attitude control system.  Precise pointing.   Large payload capability. 

Also, most commercial buses are just designed to point at the earth.

There's a second NRO bird, unless WFIRST is cannibalizing it.

[Jim]

OK, but what would be? And even if they are not designed for such missions, what do they lack for such missions?

Propellantless attitude control system.  Precise pointing.   Large payload capability. 

Also, most commercial buses are just designed to point at the earth.

There's a second NRO bird, unless WFIRST is cannibalizing it.

They are not spacecraft.  NRO only provided optical assemblies.

[tdperk]

No need for a Dragon or crew.  Just a spacecraft bus with rendezvous and docking capability and a separate
non propulsive attitude control system.  The propulsion system used for rendezvous and docking then can be used for reboost.

You left out a tiny little detail: the need to disable Hubble's own attitude control system to allow the ACS of the docked spacecraft bus to take over. Which means completely changing the way the Hubble computers operate the telescope.

Update the firmware.

Yes, we need to reconfigure the confabulator.

  too soon?

[Hog]

What about a crew Dragon with 3x crew (2x experienced Shuttle-Hubble Astros) and CMG's in the trunk?! Two of the Astronauts could perform a pair of EVAs to install new gyros and batteries and the other Astro would be there to assist them in suiting up and 'flying' the Dragon.

Can the Dragon be configured to do multiple EVAs? If the Falcon 9 is fully expended and launched to the 28.5 degree inclination orbit that Hubble is in: would the Dragon have enough delta-v to reach the telescope? Can a set of gyros and batteries fit in the Dragon's cargo trunk? I'd love to see someone do a feasibility study on a mission like this!! And could the Dragon dock with the docking unit that was left on the Hubble by the STS-125 crew? Could EVA's be done on the telescope without an RMS system? Or could the crew suffice with the pole system that was being looked at for the now abandoned Asteroid Rendezvous mission?

Or would this be a mission better suited to an Orion, launched on a Delta IV-Heavy, now that the ICPS stage is going to be 'man rated'?

Are there any Astronauts who repaired Hubble still on the active duty roster? How feasible would it be to reinstate 'Hubble Astronauts' who would still pass the physical or have only recently retired? Also: I know that it might be better to plow the mission's money into new space telescopes, or dock a 'stability' CMG control/command module to the base of Hubble...

...I'm only pondering this concept as a 'face saving' idea if - God fervently forbid - if the James Webb ends up in the drink after launch, or fails to deploy.

Bolded emphasis mine.

Types of Astronauts
Former= NASA astronaut that has left NASA or deceased
Active= eligible for flight assignment
Management= employed at NASA but are no longer eligible for flight assignment

Scott Douglas "Scooter" Altman -Former, retired 2010
Gregory Carl "Ray J" Johnson - Former retired 2013
Michael Timothy "Bueno" Good -Management- at JSC serving in the Commercial Crew Program
Katherine Megan McArthur - Active
John Mace Grunsfeld- Former retired 2016
Michael James Massimino- Former retired 2014
Andrew Jay "Drew" Feustel -Active, just returned October 4 2018 from a long duration ISS mission

Of the 7 astronauts that comprised the crew of STS-125, only McArthur and Feustal remain as "Active" astronauts that are eligible for future flight assignment.

[Halidon]

OK, but what would be? And even if they are not designed for such missions, what do they lack for such missions?

Propellantless attitude control system.  Precise pointing.   Large payload capability. 

Also, most commercial buses are just designed to point at the earth.

There's a second NRO bird, unless WFIRST is cannibalizing it.

They are not spacecraft.  NRO only provided optical assemblies.

I stand corrected,  didn't know there was no bus included. Thanks for the information.

[obi-wan]

I think it needs to be clarified that there are rate sensing gyros, and momentum/reaction wheels.  What is replaceable on Hubble is the former, but I don't know if the reaction wheels are.  It also uses replaceable magnetic torquers on the arrays for pointing.  Corrections and clarifications welcome of course!

Both the rate sensors and the reaction wheels can be changed out. The RSUs are inside the aft shroud, and one of the hardest tasks for Hubble servicing is getting the access doors open and closed (they tend to flex/jam).

[butters]

The Chandra x-ray telescope has now entered safe mode and a gyro failure is the preliminary root cause theory. It's like a bad week at the nursing home, the venerable Great Observatories are succumbing to inevitable end-of-life afflictions.

Maybe this should be in a less SpaceXy thread, but I couldn't find one just for the Hubble situation or any thread specifically about Chandra. If I missed the proper location, mods please move.

[Hog]

The Chandra x-ray telescope has now entered safe mode and a gyro failure is the preliminary root cause theory. It's like a bad week at the nursing home, the venerable Great Observatories are succumbing to inevitable end-of-life afflictions.

Maybe this should be in a less SpaceXy thread, but I couldn't find one just for the Hubble situation or any thread specifically about Chandra. If I missed the proper location, mods please move.

Those great observatories made for some great launch stories. 
 Like when Mr John Shannon, who was STS-93's Asecent/Entry Flight Director over the main flight loop pronounced "Yikes we dont need any more of those." after being informed of the LOX Low Level cutoff off the Space Shuttle Main Engines due the 405 pound Liquid Oxygen shortfall which accounted for the 15 feet per second underspeed.

STS-93 Ascent MCC FCR Internal Loop



https://waynehale.wordpress.com/2014/10/26/sts-93-we-dont-need-any-more-of-those/

[Bob Shaw]

You merely have to expand Crew Dragon's mission envelope somewhat to include servicing Hubble's cousins, the NRO's KH-11 satellites, and your funding problems are solved.   

That is nonsense

But funny.

[Lee Jay]

And at this point, I do not have much faith in Webb getting to where it's going and safely deploying with it's nearly insane 'Rube Goldberg' mechanisms and procedures.

Did you see Curiosity's EDL procedure?  To me, that was way harder to execute than the relatively pedestrian JWST deployment.  It was fast, in rough conditions (hot, dusty, etc.) and in an unpredictable environment (rocks, holes, slopes, etc.).

And, as I understand it, Hubble doesn't even have a CMG.  It has rate sensing gyros (which is what is broken), reaction wheels and magnetic torque bars for desaturating the reaction wheels.  Is that correct?

[MATTBLAK]

Someone pointed out that the Orion is really the only EVA-rated spacecraft that could visit Hubble these days. Since the Delta IV-Heavy upper stage is going to be man rated for SLS; this theoretically means that a D-IVH could launch a crew to rendezvous with Hubble. If it were a three person crew; could the CMG and battery units be carried up inside the Orion Command Module then taken out of the hatch by the crew for installation during the EVAs? I'm not sure of the hatch size in relation to the units.

Or would a Cygnus space craft bus carrying a small payload pallet be a better idea to send up first, ahead of the Orion crew? The cargo ship could link with the docking mechanism on the base of Hubble and have a basic, sideways capture point built onto the base of the pallet so the Orion could also link with the assembly. Since I can't draw the layout of the three craft together, I'm just imagining them as a rough 'T' shape. EVA translation from the Orion could be via an 'EVA Pole' as I've seen imagined for the Asteroid Redirect mission.

[MATTBLAK]

...And I note that such a mission with Orion would probably cost on the order of two or three billion dollars. Which is why I mentioned the Crew Dragon in the first place, to knock a billion or two off the cost.

Two billion dollars would be better spent mating the spare, ex-NRO Hubble-like mirror sets to a new spacecraft bus so that it could be used for Hubble like explorations.

[penguin44]

Scott Manley mentioned an interesting idea, send up a rocket and change the orbit. After that the astronauts on ISS could service the telescope.

he also stated that you would need an enormous upper stage to push it. Noting it's about a 30 degree plane change.

[pathfinder_01]

The problem with Orion on Delta IV is that while the upper stage is man rated, the whole rocket is not. Nor is the launch pad equipped . You would be better off using SLS for this if you were to use Orion Or better off launching the crew on a commercial crew craft, docking with Orion and then going to Hubble but for the 2-3 billion or so it would cost to send Orion modifying Cygnus into something like the MMSV(https://www.nasaspaceflight.com/2012/04/delving-deeper-dsh-configurations-support-craft/) would be cheaper and yield something useful for future work---like oh supporting EVA from the Deep Space Gateway and possibly if a propulsion module is attached giving the crew very limited ability to travel around CIS lunar space supporting other elements like telescopes and satelights.

[speedevil]

Scott Manley mentioned an interesting idea, send up a rocket and change the orbit. After that the astronauts on ISS could service the telescope.

he also stated that you would need an enormous upper stage to push it. Noting it's about a 30 degree plane change.

As discussed upthread.
In short, 3700m/s, 15-40 tons or so rocket.

[quagmire]

(fan) Also, Rocket parts are not LEGO elements, to be put together in whatever way one can imagine. Doesn't work that way. A D2 mission would take a lot of engineering and be diversionary. When the last HST science (positioning and desaturating) gyro gives out, safe HST and build a fixture to stow it inside a BFS and bring it home. The safe mode gyros should have some considerable life remaining presumably.

If it is feasible to send BFS to go fetch it and bring it back to Earth, why not service it, upgrade it on the ground, and relaunch Hubble?

But knowing the cost runway on things like this, probably still cheaper to build a direct Hubble replacement then my above proposal.

[vapour_nudge]

Can anyone comment on the volume and size of the replacement parts for Hubble? Is it feasible to cart them on one of the new crew vehicles?

[vt_hokie]

Both the rate sensors and the reaction wheels can be changed out. The RSUs are inside the aft shroud, and one of the hardest tasks for Hubble servicing is getting the access doors open and closed (they tend to flex/jam).

That's right, I knew that but had a memory lapse.  If I had thought about it for two seconds, it's pretty obvious that the reaction wheels would be unlikely to last as long as Hubble's been up there.  But certainly it seems to be the rate sensors that have been the limiting factor.

[Danderman]

This is an interesting topic, but there is a paucity of information here.

Can Falcon V send Crew Dragon to the required 600 km circular orbit? And with how much payload?

Can the Dragon hatch be opened briefly to allow EVA?

Can Dragon boost HST to a higher orbit?

Apart from mission specific ops costs, what would be the cost of such a mission?

Please do not answer with discussion about procurement of a new telescope, or about robotic servicing.

[hopalong]

This is an interesting topic, but there is a paucity of information here.

Can Falcon V send Crew Dragon to the required 600 km circular orbit? And with how much payload?

Can the Dragon hatch be opened briefly to allow EVA?

Can Dragon boost HST to a higher orbit?

Apart from mission specific ops costs, what would be the cost of such a mission?

Please do not answer with discussion about procurement of a new telescope, or about robotic servicing.

In answer to your first question, yes, The F9 can launch the Dragon2 to the HST with about a 5,000Kg payload.

Dragon has a 9,525Kg dry mass and the F9 with ASDS can put 14,950Kg to the HST orbit.

As for the EVA part, have an airlock module in the trunk which is detached from the trunk and the dragon then turns around and docks with?

[guckyfan]

Could Dragon be used without airlock? Have a few bottles of pressurized air to refill after EVA? Some extra bottles could be stored in the trunk.

[Danderman]

Could Dragon be used without airlock? Have a few bottles of pressurized air to refill after EVA? Some extra bottles could be stored in the trunk.

One question that follows: can the Dragon crew hatch accommodate an existing EVA suit?

[hektor]

Orion would have to be redesigned. It is not designed for long stay in the LEO environment.

I would suggest an architecture with a regular Crew Dragon plus an « Airlock Dragon ». Could be a two dragon mission : the « Airlock Dragon », a Cargo Dragon derived spacecraft with an airlock as pressurised module launched from SLC-40, and then a Crew Dragon which would launch and dock to the Airlock Dragon. In the trunk of the Airlock Dragon there would be a mechanical interface with the HST and the new ORUs for the maintenance.

The beauty of it is that the « Airlock Dragon » could reenter and be reused.

[Hauerg]

Dragon cannot support an EVA. It would require an external airlock module.

Orion can, but that's because it is designed to be able to do it, which means that the internals are fully vacuum rated (electronics) and that the entire cabin can be depressurized and pressurized again (and again?). This requires a lot of consumables. The Orion spacesuits are also designed to support it, unlike the Dragon IVA suits.

Atmosphere lost due to depressurization would be some 10 kg, so not a big deal.
Cannot see US EVA suits fitting through the top hatch.

[kevinof]

They would need to re-design the docking adapter. Dragons are active only and have no passive capability on the dock so this would need to be changed.

Orion would have to be redesigned. It is not designed for long stay in the LEO environment.

I would suggest an architecture with a regular Crew Dragon plus an « Airlock Dragon ». Could be a two dragon mission : the « Airlock Dragon », a Cargo Dragon derived spacecraft with an airlock as pressurised module launched from SLC-40, and then a Crew Dragon which would launch and dock to the Airlock Dragon. In the trunk of the Airlock Dragon there would be a mechanical interface with the HST and the new ORUs for the maintenance.

The beauty of it is that the « Airlock Dragon » could reenter and be reused.

[Danderman]

Dragon cannot support an EVA. It would require an external airlock module.

Orion can, but that's because it is designed to be able to do it, which means that the internals are fully vacuum rated (electronics) and that the entire cabin can be depressurized and pressurized again (and again?). This requires a lot of consumables. The Orion spacesuits are also designed to support it, unlike the Dragon IVA suits.

Atmosphere lost due to depressurization would be some 10 kg, so not a big deal.
Cannot see US EVA suits fitting through the top hatch.

By "hatch", I mean the primary access door for the crew, not the top hatch, which is probably only 800 - 1000 mm wide.

If EVA suits cannot fit through the Dragon outside access door, then any issues with the (proposed HST) airlock hatch could result in loss of mission and crew. Sometimes airlock hatches do fail (that happened on a Mir EVA), so the HST airlock would have to contain a secondary hatch and chamber to allow the EVA crew to take off their EVA suits to re-enter Dragon.

Or EVA suits that do fit through the Dragon side access door could magically be provided.

In all cases, EVA suits require support equipment that would have to be installed in the airlock. The ISS EVA suits require a lot of support equipment.

[darkenfast]

I believe Dragon's side hatch can only be opened either by a pad/recovery crew from the outside, or by blowing the hatch in an emergency.  That's one of the reasons why you see the "Ninjas" take so long to do close or open the thing, they are dealing with pyrotechnics in the mechanism.  Using the side hatch in space would require a redesign of the hatch.

[intrepidpursuit]

What if a module was built that had a docking adapter and support for 2 Z-2 suits and would fit in dragon's trunk? It could separate and dragon could dock with it LEM style. All systems would be tested before the dragon hatch was opened. The Z-2 suits have a built in airlock called a suit port, so they would be attached to the module the whole time with the astronauts entering from the support module. Then two astronauts would enter the Z-2 suits with the help of a third who stays with the capsule. The dragon hatch could be closed when the suits are pressurized for some extra protection from failures of the suit airlocks (though the astros in the suits obviously would be relying on success of that suit airlock). Any large components needed would either be attached to the outside of the Z-2 support module, or pre positioned by a previous flight.

This would all be purpose built hardware and none of it could return, so definitely not an inexpensive or quick undertaking. I don't know if Z-2 would be up to the task. Astronaut positioning and locomotion would have to be resolved since a canada arm is not a given; though perhaps a smaller version could also be part of the Z-2 support module.

[intrepidpursuit]

Somewhat off topic, but Starship will change the game here if successful. I doubt Hubble's solar panels could be folded back up, but recovery, repair, and relaunch may be an option now with starship. Once JWST is on position and successfully doing science, it would be great to recover Hubble and put it in a museum. I'm sure I've seen that concept addressed elsewhere.

Starship's enormous size and payload capacity certainly removes any launch limitations for a repair mission. It doesn't solve airlock and canada arm issues though, unless it does.

[Jorge]

What if a module was built that had a docking adapter and support for 2 Z-2 suits and would fit in dragon's trunk? It could separate and dragon could dock with it LEM style. All systems would be tested before the dragon hatch was opened. The Z-2 suits have a built in airlock called a suit port, so they would be attached to the module the whole time with the astronauts entering from the support module. Then two astronauts would enter the Z-2 suits with the help of a third who stays with the capsule. The dragon hatch could be closed when the suits are pressurized for some extra protection from failures of the suit airlocks (though the astros in the suits obviously would be relying on success of that suit airlock). Any large components needed would either be attached to the outside of the Z-2 support module, or pre positioned by a previous flight.

This would all be purpose built hardware and none of it could return, so definitely not an inexpensive or quick undertaking. I don't know if Z-2 would be up to the task. Astronaut positioning and locomotion would have to be resolved since a canada arm is not a given; though perhaps a smaller version could also be part of the Z-2 support module.

An airlock module/docking adapter also solves a few other issues:

Depressurizing Dragon - are the avionics/other systems rated for vacuum? With a separate airlock there is no need to depressurize Dragon.
Docking compatibility - the passive docking collar on HST is LIDS, which is *not* IDSS/NDS/SpxDS compatible.
Volume for suit storage and airlock systems

The module needs a few other systems as well. It needs at least enough GNC/prop capability to hold attitude for Dragon to dock with it. It will block the Dragon's nose cone thrusters, so the module would need to provide its own, commandable by the Dragon. It will block the Dragon's GNC sensors, so the module would also need to provide its own, with a command/data passthrough for the sensor data to reach Dragon.

If the module is launched separately on another F9, it could be made big enough to accommodate external robotics/HST components. Clearance with the Dragon nose cone would constrain the geometry of the module on that side.

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

[Cherokee43v6]

Interesting to see this thread come back from the dead.

Way upthread there was discussion of a Dragon/Cygnus concept where the airlock would be on the Cygnus.

Since this is a SpaceX thread and since this originally was put up SpaceX was awarded a supply contract for Gateway, how about a DragonXL/CrewDragon mission concept?

Don't forget that the Space Shuttle's payload bay acted as a work platform to hold the Hubble.  It provided places to hold the replacement equipment ready for installation.  It provided the robotic arm that was required to move the astronauts into the the correct positions and hold them steady while performing the work.  Finally, it provided a measure of safety (and mental orientation), in that if an astronaut did happen to come loose from their tethers or bindings, nearly half their available sky was the ship.

Crew Dragon would not be able to provide any of that on its own.

[groknull]

What if a module was built that had a docking adapter and support for 2 Z-2 suits and would fit in dragon's trunk? It could separate and dragon could dock with it LEM style. All systems would be tested before the dragon hatch was opened. The Z-2 suits have a built in airlock called a suit port, so they would be attached to the module the whole time with the astronauts entering from the support module. Then two astronauts would enter the Z-2 suits with the help of a third who stays with the capsule. The dragon hatch could be closed when the suits are pressurized for some extra protection from failures of the suit airlocks (though the astros in the suits obviously would be relying on success of that suit airlock). Any large components needed would either be attached to the outside of the Z-2 support module, or pre positioned by a previous flight.

This would all be purpose built hardware and none of it could return, so definitely not an inexpensive or quick undertaking. I don't know if Z-2 would be up to the task. Astronaut positioning and locomotion would have to be resolved since a canada arm is not a given; though perhaps a smaller version could also be part of the Z-2 support module.

An airlock module/docking adapter also solves a few other issues:

Depressurizing Dragon - are the avionics/other systems rated for vacuum? With a separate airlock there is no need to depressurize Dragon.
Docking compatibility - the passive docking collar on HST is LIDS, which is *not* IDSS/NDS/SpxDS compatible.
Volume for suit storage and airlock systems

The module needs a few other systems as well. It needs at least enough GNC/prop capability to hold attitude for Dragon to dock with it. It will block the Dragon's nose cone thrusters, so the module would need to provide its own, commandable by the Dragon. It will block the Dragon's GNC sensors, so the module would also need to provide its own, with a command/data passthrough for the sensor data to reach Dragon.

If the module is launched separately on another F9, it could be made big enough to accommodate external robotics/HST components. Clearance with the Dragon nose cone would constrain the geometry of the module on that side.

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

Many of the features and capabilities you suggest for an airlock module / docking adapter are already in the design of the Dragon XL for Lunar Gateway resupply.

Probable modifications needed:
- Addition of an active passive docking port on the cargo end of the Dragon XL with clearance for Dragon 2 nose cone.
- Addition of a sideways facing EVA hatch.
- Addition of external storage for mission specific modules and tools.

Features already present:
- Forward facing thrusters to functionally replace the occluded forward thrusters on the Dragon 2 docked aft.
- Solar arrays.
- Power, data and command connections already in docking port design.
- Maneuvering thrusters.
- Long duration capability.
- Standard docking port forward - could dock with ISS and left there between Hubble servicing (and other) missions.  Aft docking port would still allow visiting vehicles to dock.

Edit: active/passive

[Danderman]

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

I am not sure that HST has enough control authority to operate usefully with a multi ton module hanging on the back.

[intrepidpursuit]

What if a module was built that had a docking adapter and support for 2 Z-2 suits and would fit in dragon's trunk? It could separate and dragon could dock with it LEM style. All systems would be tested before the dragon hatch was opened. The Z-2 suits have a built in airlock called a suit port, so they would be attached to the module the whole time with the astronauts entering from the support module. Then two astronauts would enter the Z-2 suits with the help of a third who stays with the capsule. The dragon hatch could be closed when the suits are pressurized for some extra protection from failures of the suit airlocks (though the astros in the suits obviously would be relying on success of that suit airlock). Any large components needed would either be attached to the outside of the Z-2 support module, or pre positioned by a previous flight.

This would all be purpose built hardware and none of it could return, so definitely not an inexpensive or quick undertaking. I don't know if Z-2 would be up to the task. Astronaut positioning and locomotion would have to be resolved since a canada arm is not a given; though perhaps a smaller version could also be part of the Z-2 support module.

An airlock module/docking adapter also solves a few other issues:

Depressurizing Dragon - are the avionics/other systems rated for vacuum? With a separate airlock there is no need to depressurize Dragon.
Docking compatibility - the passive docking collar on HST is LIDS, which is *not* IDSS/NDS/SpxDS compatible.
Volume for suit storage and airlock systems

The module needs a few other systems as well. It needs at least enough GNC/prop capability to hold attitude for Dragon to dock with it. It will block the Dragon's nose cone thrusters, so the module would need to provide its own, commandable by the Dragon. It will block the Dragon's GNC sensors, so the module would also need to provide its own, with a command/data passthrough for the sensor data to reach Dragon.

If the module is launched separately on another F9, it could be made big enough to accommodate external robotics/HST components. Clearance with the Dragon nose cone would constrain the geometry of the module on that side.

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

Many of the features and capabilities you suggest for an airlock module / docking adapter are already in the design of the Dragon XL for Lunar Gateway resupply.

Probable modifications needed:
- Addition of an active passive docking port on the cargo end of the Dragon XL with clearance for Dragon 2 nose cone.
- Addition of a sideways facing EVA hatch.
- Addition of external storage for mission specific modules and tools.

Features already present:
- Forward facing thrusters to functionally replace the occluded forward thrusters on the Dragon 2 docked aft.
- Solar arrays.
- Power, data and command connections already in docking port design.
- Maneuvering thrusters.
- Long duration capability.
- Standard docking port forward - could dock with ISS and left there between Hubble servicing (and other) missions.  Aft docking port would still allow visiting vehicles to dock.

Edit: active/passive

The whole reason for using the X-2 suits is their self contained suit port airlock capability, which would eliminate the need for extensive support systems and an EVA suit sized airlock.

Dragon has capability to operate in proximity to station without using its nose thrusters. I know it uses those thrusters for orbit raising and lowering maneuvers, but it does have at least some control capability with those thrusters disabled. I don't know what dragons control capabilities would be with a mass on the nose. I think that falls into the "rockets are not legos" category of possibility.

I think that adding an additional hatch it a capsule, especially on a different axis, would basically require a complete redesign of the pressure vessel. Flying the support module on a separate flight does require it to have power generation, station keeping, navigation, and a whole spacecraft bus worth of capabilities that could hopefully be avoided by carrying it on dragon. If it does have all those capabilities, then maybe having it station keep near HST is a possible option. Designing an autonomous, long lived, human rated service craft seems like massive undertaking to me though. I would think that with the diminishing scientific value of HST I'd think that minimizing cost or developing things that have uses elsewhere like the Z-2 suit would be useful goals.

All that said, the Northrop maintenance vehicle might be a good place to start with a service craft bus if we were to go that route.

[Jorge]

What if a module was built that had a docking adapter and support for 2 Z-2 suits and would fit in dragon's trunk? It could separate and dragon could dock with it LEM style. All systems would be tested before the dragon hatch was opened. The Z-2 suits have a built in airlock called a suit port, so they would be attached to the module the whole time with the astronauts entering from the support module. Then two astronauts would enter the Z-2 suits with the help of a third who stays with the capsule. The dragon hatch could be closed when the suits are pressurized for some extra protection from failures of the suit airlocks (though the astros in the suits obviously would be relying on success of that suit airlock). Any large components needed would either be attached to the outside of the Z-2 support module, or pre positioned by a previous flight.

This would all be purpose built hardware and none of it could return, so definitely not an inexpensive or quick undertaking. I don't know if Z-2 would be up to the task. Astronaut positioning and locomotion would have to be resolved since a canada arm is not a given; though perhaps a smaller version could also be part of the Z-2 support module.

An airlock module/docking adapter also solves a few other issues:

Depressurizing Dragon - are the avionics/other systems rated for vacuum? With a separate airlock there is no need to depressurize Dragon.
Docking compatibility - the passive docking collar on HST is LIDS, which is *not* IDSS/NDS/SpxDS compatible.
Volume for suit storage and airlock systems

The module needs a few other systems as well. It needs at least enough GNC/prop capability to hold attitude for Dragon to dock with it. It will block the Dragon's nose cone thrusters, so the module would need to provide its own, commandable by the Dragon. It will block the Dragon's GNC sensors, so the module would also need to provide its own, with a command/data passthrough for the sensor data to reach Dragon.

If the module is launched separately on another F9, it could be made big enough to accommodate external robotics/HST components. Clearance with the Dragon nose cone would constrain the geometry of the module on that side.

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

Many of the features and capabilities you suggest for an airlock module / docking adapter are already in the design of the Dragon XL for Lunar Gateway resupply.

Yes, I left unsaid the (tautological?) statement that however SpaceX implements the airlock module, it would make sense to use an existing design (Dragon or Dragon XL) as a starting point. Perhaps I shouldn't have left that unsaid.

[Jorge]

If designed properly, the module could be left behind on HST to facilitate further servicing missions.

I am not sure that HST has enough control authority to operate usefully with a multi ton module hanging on the back.

I am not sure either, but decided to mention the possibility, at least. (And the "If designed properly" clause leaves a lot of wiggle room for the module to be designed to assist HST control, at the cost of modifying HST to command the module.)

[Danderman]

This is an interesting discusión, but it would be nice if concepts could focus on limiting cost. Otherwise the “why not build a new telescope” meme would emerge.

[watermod]

This is an interesting discusión, but it would be nice if concepts could focus on limiting cost. Otherwise the “why not build a new telescope” meme would emerge.

Wait a year until Musk has a StarShip that opens it's maw to release mass numbers of StarLink sats.   
After it releases a load it can tank up from a tanker StarShip then go to Hubble with an open maw.
Have a small arm and several tethers on it.  Use the arm to tether Hubble and Hubble's solar arrays.
Have a giant bolt cutter on the end of the arm to snip off all the solar arrays and anything else sticking too far out.
Then use the arm to move it all inside the StarShip Maw.  Close the maw and return to Earth with Hubble. 
Fix it or put it in a museum ... whatever.   It's safely down and can be repaired on Earth.   Relaunch with StarShip and a
refueling should not be too bad.

[Danderman]

There is a risk that waiting for a Starship that can service HST might take longer than HST's remaining lifetime.

This topic is about servicing HST using Dragon.

[su27k]

I think the Mission Extension Vehicle (MEV) concept mentioned by Jim and russianhalo117 is a much better bet than trying to mod Crew Dragon for an one time only crewed service mission.

[Danderman]

I think the Mission Extension Vehicle (MEV) concept mentioned by Jim and russianhalo117 is a much better bet than trying to mod Crew Dragon for an one time only crewed service mission.

This is a robotic solution?

[su27k]

Yes, robotic mission. Back when they proposed it, Crew Dragon hasn't demonstrated automated docking with ISS, nor has NG MEV-1 demonstrated docking with a GEO satellite. Now these have all become reality, I think a robotic service mission should be a no-brainer.

[Danderman]

I was really hoping that this topic would stick to the issues around a Dragon mission to Hubble. If someone wants to talk about robotic missions, or building a new telescope, they are free to start a new topic for that.

One reason for a crewed mission is to replace gyros. Easy job for humans.

[Danderman]

In the early part of the last decade, SpaceX produced a presentation either about or including servicing of HST with Dragon. Anyone have a copy of that presentation?

It's probably somewhere on this site.

It might even be in this topic... 

[su27k]

I'm guessing this is the presentation you're looking for: https://forum.nasaspaceflight.com/index.php?topic=28805.msg893965#msg893965

I didn't know this presentation existed before, very interesting. That whole thread is worth re-reading, laid out a lot of problems with a crewed service mission using Dragon.

[Danderman]

I'm guessing this is the presentation you're looking for: https://forum.nasaspaceflight.com/index.php?topic=28805.msg893965#msg893965

I didn't know this presentation existed before, very interesting. That whole thread is worth re-reading, laid out a lot of problems with a crewed service mission using Dragon.

Bingo.

It seems a very limited and cumbersome approach, using a robotic arm that would be discarded during the mission. There almost doesn't seem to be a role for a crew in this architecture, since the arm could be operated from the ground.

It looks like the 2010 version of Dragon could not support EVA, don't know if that is true for the 2020 Crew Dragon.

[DistantTemple]

This is an interesting discusión, but it would be nice if concepts could focus on limiting cost. Otherwise the “why not build a new telescope” meme would emerge.

Wait a year until Musk has a StarShip that opens it's maw to release mass numbers of StarLink sats.   
After it releases a load it can tank up from a tanker StarShip then go to Hubble with an open maw.
Have a small arm and several tethers on it.  Use the arm to tether Hubble and Hubble's solar arrays.
Have a giant bolt cutter on the end of the arm to snip off all the solar arrays and anything else sticking too far out.
Then use the arm to move it all inside the StarShip Maw.  Close the maw and return to Earth with Hubble. 
Fix it or put it in a museum ... whatever.   It's safely down and can be repaired on Earth.   Relaunch with StarShip and a
refueling should not be too bad.

Not very safe for the belly flop manoeuvre! And then the boost upright.. then deceleration to land!. It will be well shaken, although at least not stirred!
So it would need to be very securely grasped by SS. I don't know the attachment points on Hubble, and if they could be reused securely.
If its destined for a museum, moderate damage may not be a critical issue. But it must land without crashing.... If thats unlikely, then put off the attempt until SS is improved... and then maybe we're back on the human servicing!

[John Santos]

Not very safe for the belly flop manoeuvre! And then the boost upright.. then deceleration to land!. It will be well shaken, although at least not stirred!
So it would need to be very securely grasped by SS. I don't know the attachment points on Hubble, and if they could be reused securely.
If its destined for a museum, moderate damage may not be a critical issue. But it must land without crashing.... If thats unlikely, then put off the attempt until SS is improved... and then maybe we're back on the human servicing!

Hubble was designed to be retrieved on the Shuttle.  It has standard shuttle trunion attachment points and can easily withstand the vertical, horizontal and rotational forces of a shuttle reentry and landing.  Do we know anything about how SS reentry compares to that?

The solar arrays are designed to be removable and replaceable.  They may also be retractable, but on one servicing mission, IIRC they tried to retract them but couldn't so they just released the arrays and they most likely soon reentered on their own (low mass, high drag.)

[Coastal Ron]

Not very safe for the belly flop manoeuvre! And then the boost upright.. then deceleration to land!. It will be well shaken, although at least not stirred!
So it would need to be very securely grasped by SS. I don't know the attachment points on Hubble, and if they could be reused securely.
If its destined for a museum, moderate damage may not be a critical issue. But it must land without crashing.... If thats unlikely, then put off the attempt until SS is improved... and then maybe we're back on the human servicing!

Hubble was designed to be retrieved on the Shuttle.  It has standard shuttle trunion attachment points and can easily withstand the vertical, horizontal and rotational forces of a shuttle reentry and landing.  Do we know anything about how SS reentry compares to that?

Hubble launched in a vertical position on the Shuttle so the real question is how would it do with horizontal forces. But if it was designed to be retrieved by the Shuttle, then it should do OK with a Starship retrieval.

[Coastal Ron]

I'm guessing this is the presentation you're looking for: https://forum.nasaspaceflight.com/index.php?topic=28805.msg893965#msg893965

I didn't know this presentation existed before, very interesting. That whole thread is worth re-reading, laid out a lot of problems with a crewed service mission using Dragon.

Bingo.

It seems a very limited and cumbersome approach, using a robotic arm that would be discarded during the mission. There almost doesn't seem to be a role for a crew in this architecture, since the arm could be operated from the ground.

It looks like the 2010 version of Dragon could not support EVA, don't know if that is true for the 2020 Crew Dragon.

In-space servicing by LEO spacecraft could be doable if a LEO "workshop" was used. Such a "workshop" would include an airlock, and it would also host the robotic arm. It could also be a free flying science platform when it wasn't needed otherwise.

Such a vehicle could be based on the current Cygnus spacecraft, with a modification to the Pressurized Cargo Module (PCM) where the end with a docking hatch was for human occupation, and on the far end would be the airlock with a side hatch for egress/ingress.

Because Dragon (or whoever) would be docked on the cargo entrance end, and the Cygnus Service Module (SM) is on the other end, there would need to be two arms (similar to the SpaceX concept), with one holding the target vehicle, and the other for servicing.

If we plan on doing in-space servicing with humans we need something like this anyways.

[Danderman]

I'm guessing this is the presentation you're looking for: https://forum.nasaspaceflight.com/index.php?topic=28805.msg893965#msg893965

I didn't know this presentation existed before, very interesting. That whole thread is worth re-reading, laid out a lot of problems with a crewed service mission using Dragon.

Bingo.

It seems a very limited and cumbersome approach, using a robotic arm that would be discarded during the mission. There almost doesn't seem to be a role for a crew in this architecture, since the arm could be operated from the ground.

It looks like the 2010 version of Dragon could not support EVA, don't know if that is true for the 2020 Crew Dragon.

In-space servicing by LEO spacecraft could be doable if a LEO "workshop" was used. Such a "workshop" would include an airlock, and it would also host the robotic arm. It could also be a free flying science platform when it wasn't needed otherwise.

Such a vehicle could be based on the current Cygnus spacecraft, with a modification to the Pressurized Cargo Module (PCM) where the end with a docking hatch was for human occupation, and on the far end would be the airlock with a side hatch for egress/ingress.

Because Dragon (or whoever) would be docked on the cargo entrance end, and the Cygnus Service Module (SM) is on the other end, there would need to be two arms (similar to the SpaceX concept), with one holding the target vehicle, and the other for servicing.

If we plan on doing in-space servicing with humans we need something like this anyways.

Let me know where you can find money in the Federal budget for all that.

[cosmicvoid]

After reading all 101 posts in this thread, I'm unable to find an explanation of what "CMG" means. Is this an acronym that everybody but me knows?

[markododa]

After reading all 101 posts in this thread, I'm unable to find an explanation of what "CMG" means. Is this an acronym that everybody but me knows?

It means Control moment gyroscope https://en.wikipedia.org/wiki/Control_moment_gyroscope

[cosmicvoid]

It means Control moment gyroscope https://en.wikipedia.org/wiki/Control_moment_gyroscope

Thank you!

[Danderman]

CMGs are for ISS, not HST.

[Tommyboy]

CMGs are for ISS, not HST.

Then what does Hubble use to control its orientation instead of CMGs?

[cdebuhr]

CMGs are for ISS, not HST.

Then what does Hubble use to control its orientation instead of CMGs?

Hubble uses reaction wheels.  ts also got a number of magnetorquers used to keep the reaction wheels within their nominal range of stored angular momentum.

[Coastal Ron]

Bingo.

It seems a very limited and cumbersome approach, using a robotic arm that would be discarded during the mission. There almost doesn't seem to be a role for a crew in this architecture, since the arm could be operated from the ground.

It looks like the 2010 version of Dragon could not support EVA, don't know if that is true for the 2020 Crew Dragon.

In-space servicing by LEO spacecraft could be doable if a LEO "workshop" was used. Such a "workshop" would include an airlock, and it would also host the robotic arm. It could also be a free flying science platform when it wasn't needed otherwise.

Such a vehicle could be based on the current Cygnus spacecraft, with a modification to the Pressurized Cargo Module (PCM) where the end with a docking hatch was for human occupation, and on the far end would be the airlock with a side hatch for egress/ingress.

Because Dragon (or whoever) would be docked on the cargo entrance end, and the Cygnus Service Module (SM) is on the other end, there would need to be two arms (similar to the SpaceX concept), with one holding the target vehicle, and the other for servicing.

If we plan on doing in-space servicing with humans we need something like this anyways.

Let me know where you can find money in the Federal budget for all that.

There is no constitutional limit to how much money NASA can be provided, so there is no need to "find" money, there is only the need to identify a need great enough for Congress to fund it.

But if you wanted to keep NASA's budget in the range it is today, then there would be plenty of room in the budget if the SLS and Orion were cancelled. And seeing how what I'm proposing is very similar to the Gateway, I'd say the requirements could be merged Artemis, so not really a big budget bump to build it.

Of course cancelling the SLS and Orion are the biggest issues to address, but I've been suggesting for a long time that the U.S. President should declare that we are extending our economic sphere of influence out into space, and the first step is to create a reusable transportation out to the region of the Moon. This can be supported by existing commercial launchers (all of them, not just SpaceX), which replaces the SLS, and the reusable space-only transportation elements can be the replacement for the Orion.

Essentially this builds a "Transcontinental Railroad" equivalent to the region of the Moon, which would be operated by the private sector (and international partners too I hope). And this puts the elements needed for in-space servicing in place too, or provides most of it so that the unique elements don't cost too much or take too much time to build.

My $0.02

[Hog]

Picture 1: ISS Control Moment Gyroscope

Picture 2: HST Reaction Wheels

[pb2000]

I think moving Hubble to the ISS is the best bet as it opens a ton of opportunities. Would a stripped down Dragon 1 refitted with aux tanks have enough delta-V to do it?

[Orbiter]

I think moving Hubble to the ISS is the best bet as it opens a ton of opportunities. Would a stripped down Dragon 1 refitted with aux tanks have enough delta-V to do it?

If I'm doing my math right, not even close. The ΔV required for a 23 degree inclination change at 600km would be roughly 3 km/s.

[Danderman]

What would be the capability of a Crew Dragon to increase the altitude of HST, assuming a standard propellant load?

[Robotbeat]

Looks like Dandermann is the one that looks most prescient here.