Author Topic: Crew Dragon or Orion to Hubble for CMG Replacement?  (Read 39133 times)

Offline MATTBLAK

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #60 on: 10/14/2018 02:40 am »
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.
« Last Edit: 10/14/2018 02:42 am by MATTBLAK »
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Offline MATTBLAK

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #61 on: 10/14/2018 02:45 am »
...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.
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Offline penguin44

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #62 on: 10/14/2018 05:10 am »
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.

Offline pathfinder_01

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #63 on: 10/14/2018 05:30 am »
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.
« Last Edit: 10/14/2018 05:45 am by pathfinder_01 »

Offline speedevil

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #64 on: 10/14/2018 10:14 am »
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.

Offline quagmire

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Re: Crew Dragon to Hubble for CMG Replacement?
« Reply #65 on: 10/14/2018 01:33 pm »
(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. :P

Offline vapour_nudge

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #66 on: 10/14/2018 01:38 pm »
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?

Offline vt_hokie

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #67 on: 10/15/2018 04:48 am »

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.

Offline Danderman

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #68 on: 12/06/2020 07:42 am »
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.
« Last Edit: 12/06/2020 07:43 am by Danderman »

Offline hopalong

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #69 on: 12/06/2020 08:07 am »
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?

Offline guckyfan

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #70 on: 12/06/2020 09:49 am »
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.

Offline Danderman

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #71 on: 12/06/2020 09:51 am »
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?


Offline hektor

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #72 on: 12/06/2020 10:23 am »
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.
« Last Edit: 12/06/2020 10:31 am by hektor »

Offline Hauerg

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Re: Crew Dragon to Hubble for CMG Replacement?
« Reply #73 on: 12/06/2020 10:54 am »
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.

Offline kevinof

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #74 on: 12/06/2020 12:24 pm »
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.

Offline Danderman

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #75 on: 12/06/2020 12:41 pm »
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.


« Last Edit: 12/06/2020 12:58 pm by Danderman »

Offline darkenfast

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #76 on: 12/06/2020 06:31 pm »
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.
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Offline intrepidpursuit

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #77 on: 12/06/2020 07:00 pm »
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.
« Last Edit: 12/06/2020 07:07 pm by intrepidpursuit »

Offline intrepidpursuit

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #78 on: 12/06/2020 07:14 pm »
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.

Offline Jorge

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Re: Crew Dragon or Orion to Hubble for CMG Replacement?
« Reply #79 on: 12/06/2020 07:30 pm »
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.
« Last Edit: 12/06/2020 07:32 pm by Jorge »
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