Author Topic: Polaris Program (Dragon and Starship crewed missions led by Isaacman)  (Read 72740 times)

Offline AstroWare

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I think much may depend on if it's a boost only or a boost and service mission... If no eva is planned, I think they go nose-first docking. If they plan an EVA, then Aft-first. And either way - spaceX has the expertise to find the best technical option.
If they decide to do a boost-only mission, I suspect they will decide to not do it as a crewed Polaris mission, but as a robotic mission - probably pitched to NASA as a commercial offering to be paid for by the agency. ( ... )

There is a good chance that a Polaris 2 mission could cost >>>NASA<<< less than purchasing a traditionally procured robotic mission.

Offline hektor

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Pushing an asset in a different orbit with a crew capsule... makes me think of Artemis IV...

Offline geza

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The fact that they consider themselves ready to officially drag NASA into this with a Space Act Agreement suggests that they have some clear ideas already "in-house" as to what they can do with Dragon for an EVA mission at Hubble. They've probably got some fairly concrete sketches drawn up for how to transport replacement parts to Hubble along with crew. My guess is that they needed the Space Act Agreement in order to start discussing solid details about exactly which components NASA would most like to replace on Hubble and how they could go about procuring them.

For a repair mission they will need a robotic arm, or an innovative other way of moving the components.

Offline waveney

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I think that the highest priority maintenance would be replacing the Giro's - They are down to 3 of 6, with one getting unhappy.  It would still be able to some work with two, but not all observations.   It has been down to 2 once before.  The Giro units are relatively small and should be easily serviced.

Dragon could easily carry those inside or in its trunk.

Edit to add: For details of the Giros see : https://asd.gsfc.nasa.gov/archive/hubble/a_pdf/news/facts/FS12.pdf

While the instruments could be replaced, they would be a larger undertaking.  They could be carried up in the trunk, but are probably too large to bring back down again inside the dragon.
« Last Edit: 09/30/2022 09:50 am by waveney »

Online eeergo

If the study just focuses on reboost, it clearly can be done more efficiently with a dedicated robotic tug. No need to bring a messy crew (with all the mass penalties it implies, including for safety) along for the ride, who moreover needs to come back quickly should some issue arise. Another matter is if they can squeeze in some kind of servicing beyond orbital maintenance, but that's a stretch in Dragon considering how much support equipment to hold Hubble and the ancilliary support tools the Shuttle had to carry (apart from the servicing components themselves), which Dragon cannot trivially accommodate courtesy of being volume-limited, even disregarding upmass limitations which surely are also there.
-DaviD-

Offline kevinof

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Sounds like a plan. Doesn't all have to be done in one go - you could have one mission to replace the Giros and when completed do an orbit boost. A second mission to replace instruments could be done when they figure out a way to carry and manoeuvre the instruments.


I think that the highest priority maintenance would be replacing the Giro's - They are down to 3 of 6, with one getting unhappy.  It would still be able to some work with two, but not all observations.   It has been down to 2 once before.  The Giro units are relatively small and should be easily serviced.

Dragon could easily carry those inside or in its trunk.

While the instruments could be replaced, they would be a larger undertaking.  They could be carried up in the trunk, but are probably too large to bring back down again inside the dragon.

Offline TrevorMonty





I think much may depend on if it's a boost only or a boost and service mission... If no eva is planned, I think they go nose-first docking. If they plan an EVA, then Aft-first. And either way - spaceX has the expertise to find the best technical option.
If they decide to do a boost-only mission, I suspect they will decide to not do it as a crewed Polaris mission, but as a robotic mission - probably pitched to NASA as a commercial offering to be paid for by the agency. ( ... )

There is a good chance that a Polaris 2 mission could cost &gt;&gt;&gt;NASA&lt;&lt;&lt; less than purchasing a traditionally procured robotic mission.

Great way to split Dragon missions cost between NASA and private crew.

Online edzieba

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If the study just focuses on reboost, it clearly can be done more efficiently with a dedicated robotic tug.
Which could just as well be Dragon.
Any tug needs to have a LIDS ring (the non-active part was inherited by IDSS), RCS, docking cameras, autonomous and remote operation capability, etc, which Dragon has. Dragon also has the advantage of already being developed and flying, so unlike a dedicated tug it's development cost (on top of any actual missions cost) is minimal, as is development time.

Offline kevinof

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Agreed - Why is it that when something is offered "almost" off the shelf we instead suggest a tonne of new development to achieve the same result?

While not perfect or ideal, crewed Dragon is probably the simplest and cheapest way to get this mission done.

If the study just focuses on reboost, it clearly can be done more efficiently with a dedicated robotic tug.
Which could just as well be Dragon.
Any tug needs to have a LIDS ring (the non-active part was inherited by IDSS), RCS, docking cameras, autonomous and remote operation capability, etc, which Dragon has. Dragon also has the advantage of already being developed and flying, so unlike a dedicated tug it's development cost (on top of any actual missions cost) is minimal, as is development time.

Offline FutureSpaceTourist

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Didn't have time to post this yesterday, but I love Jessica's answer to the question of what SpaceX gets out of the (unfunded) study (my emphasis):

Quote from: Joey Roulette (Reuters)
What does SpaceX get out of this study? Will this experience inform how you guys plan to dock tanker Starships in orbit, or other things that aren't ISS?

Quote from: Jessica Jensen (SpaceX)
So first of all Hubble is a national asset and it's really an honor for us if we would be able to extend its lifetime, So I think first of all in the near-term that's just a great goal in itself. But SpaceX really sees the future in that we're a spacefaring civilisation and that means that there are spaceships flying all over the place, there is on-orbit refueling, there's vehicles from various companies, there's space stations from various companies, we do things like service very expensive spacecraft in higher orbits, we continue to service telescopes, we build bases on the moon and mars and do all kinds of things. And so when you look forward to this spacefaring civilisation, missions like this where companies are learning to adapt and figure out ways to dock to older vehicles and to basically make two vehicles in space compatible with each another, that weren't initially designed to be that way, I think that's an amazing capability and that's how the industry needs to move forward.

Online eeergo

Easy answer: an off-the-shelf Cargo Dragon could do it equally well, adding significant upmass, mission timelime margins, stability, easing constraints... Doesn't hype Polaris though.
-DaviD-

Offline FutureSpaceTourist

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https://twitter.com/rookisaacman/status/1575835601550462976

Quote
Should the study supports going forward with a mission we would aim to leave Hubble in a healthier & more capable state in addition to a boosted orbit. That is really the purpose of the study.  Hubble deserves to operate for decades longer alongside JWST.

Offline Greg Hullender

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I saw in the article that they talked about pushing Hubble up just 24 miles or so. I was wondering if it might make more sense to push it up a lot higher. Not into the Van Allen belts, of course, but maybe just under them, say 600 miles up. Then it wouldn't have to be lifted again nor would there need to be a disposal mission--it would stay there for centuries.

In the unlikely event they wanted another human servicing mission, I wonder if a Dragon could do it. I haven't been able to find anything that says how high Dragon can get.


Offline Welsh Dragon

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Easy answer: an off-the-shelf Cargo Dragon could do it equally well, adding significant upmass, mission timelime margins, stability, easing constraints... Doesn't hype Polaris though.
Technically totally agreed. But in this case it might be the mission is only (potentially) happening because of the crew, even if it would make infinitely more sense to do it without one (assuming it's 'just' reboost).

Online edzieba

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I saw in the article that they talked about pushing Hubble up just 24 miles or so. I was wondering if it might make more sense to push it up a lot higher. Not into the Van Allen belts, of course, but maybe just under them, say 600 miles up. Then it wouldn't have to be lifted again nor would there need to be a disposal mission--it would stay there for centuries.
Q Mike Wall Space.com - are you looking for a 30 km boost? How much longevity does it add?  Study includes servicing too? Or just boost.   

A Patrick - we will study what the max boost is.. prelim 40-70 km boost possible... if we can get to 600km that adds 20 years of orbit life. The study will also examine waht else can we do... not as complex as Shuttle service but anything is on the table

Offline woods170

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Note the idea originated with SpaceX:


Quote
Zurbuchen: "A few months ago SpaceX approached NASA with the idea for a study of how a commercial crew could help boost our Hubble spacecraft into a higher orbit, that would extend its observational lifetime."

NASA & SpaceX signed a Space Act Agreement for a feasibility study.

Yes. This was SpaceX's idea. One of several they have proposed actually. And it is one of the things I was hinting at when I posted this little nugget 7.5 months ago:

They won’t invest heavily in further Dragon development.

I am not allowed to go into details (per my sources), but I can say that your assessment is not entirely correct.
« Last Edit: 09/30/2022 02:29 pm by woods170 »

Offline hektor

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My favorite way to do this : two Dragons

1) Dragon airlock (with a bigger side hatch which allows to do EVA with a back pack) and a docking interface with Hubble in the trunk ; it is derived from Cargo Dragon (no Super Dracos)
2) Crew Dragon : carry the crew and the ORUs in the trunk.

Dragon A/L docks with the Hubble at Dragon A/L trunk level. Crew Dragon docks with the front docking of the Dragon A/L.

EVA is through side hatch of Dragon A/L, first installing hand rails and so forth to create a path between both trunks. Then the ORUs are manually transferred along the created paths by the EVA crew

Airlock is built in a Dragon to make it recoverable, reusable and recover the suits. All what is lost is the Hubble interface in the trunk and the spent ORUs in the other trunk (also some spent ORUs could be put in the Airlock Dragon for return and expertise)

Reboost is performed with the thrusters around the front hatch of the Dragon A/L once the crew Dragon has separated so it is the cleanest possible wrt Hubble

The reboost is performed with the non human rated Dragon so the propellant quantity devoted to reboost can be higher (no need for propellant for ejection at launch for instance).

Non EVA crew can remain in a pressurized environment in the Crew Dragon during the EVAs.
« Last Edit: 09/30/2022 02:52 pm by hektor »

Online eeergo

Easy answer: an off-the-shelf Cargo Dragon could do it equally well, adding significant upmass, mission timelime margins, stability, easing constraints... Doesn't hype Polaris though.
Technically totally agreed. But in this case it might be the mission is only (potentially) happening because of the crew, even if it would make infinitely more sense to do it without one (assuming it's 'just' reboost).

Sure, I can see that - but then this study is more about "we want to add value to this mission which we already decided will happen, at comparatively little cost" rather than "we're studying ways to boost Hubble in the next few years, and think the best way to go about it is with Polaris and its crew (who supposedly will be concentrated on their sizeable main goals: first private spacewalk, optical T/C, health experiments...)".
-DaviD-

Online edzieba

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Easy answer: an off-the-shelf Cargo Dragon could do it equally well, adding significant upmass, mission timelime margins, stability, easing constraints... Doesn't hype Polaris though.
Technically totally agreed. But in this case it might be the mission is only (potentially) happening because of the crew, even if it would make infinitely more sense to do it without one (assuming it's 'just' reboost).

Sure, I can see that - but then this study is more about "we want to add value to this mission which we already decided will happen, at comparatively little cost" rather than "we're studying ways to boost Hubble in the next few years, and think the best way to go about it is with Polaris and its crew (who supposedly will be concentrated on their sizeable main goals: first private spacewalk, optical T/C, health experiments...)".
Polaris Dawn (first private spacewalk) is not related to any potential Hubble reboost mission, and will likely fly before this study is even completed.

Offline Reynold

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My prediction is that they will end up doing 2 missions, first a cargo Dragon reboost, which might just need a docking adaptor for the docking system installed on the Hubble in the last servicing mission.  Presumably in the trunk, so the Dragon thrusters can point the right way to boost the Hubble.  NASA may or may not be able to scrape together some money to pay SpaceX to develop the docking adaptor and fly the mission, but it would be pocket change compared to what they would have spent to deorbit it.  This would be pretty low risk, NASA has gotten very comfortable with cargo Dragon. 

Then a Polaris manned mission with Jared and at least one NASA astronaut to do servicing, at a minimum a gyro swap out.  By then, EVA from the Dragon will have been tested by Jared and crew on Polaris Dawn.  NASA will presumably pay something to fly their astronaut, but most of the NASA money for that phase will probably go into building whatever parts are getting swapped out and training on what they want to do, support for the mission, etc. 

I'm guessing there will be a lot of support in NASA to do this, though, far more of the public has heard of Hubble and likes it than has heard of Artemis. 

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