Author Topic: Crew Dragon or Orion to Hubble for CMG Replacement?  (Read 10483 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.

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