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#1 2020-06-16 10:10:27

tahanson43206
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Registered: 2018-04-27
Posts: 7,616

NASA Mars Sample Return Mission

The article at the link below reports on progress in defining the technology to be used for the proposed Mars sample return mission, under study by NASA and affiliated researchers.

https://spaceflightnow.com/2020/04/20/n … f-of-mars/

Of particular interest may be the decision to settle on use of a solid rocket motor to provide reliable launch service from the surface of Mars.

I am hoping GW Johnson will provide his insight on this decision, and its implications for future Mars missions, including ones  including human explorers.

Quite recently, in this forum, GW Johnson published notes on a proposal to design an exploration mission that would be designed entirely around storable liquid fuel/oxidizer components, to insure the safe return of the explorers, by eliminating risk of attempting to make fuel and oxidizer at Mars.

The use of solid rocket motors no doubt has its own risks, and that use has the distinct disadvantage that each such rocket transported to Mars can be used only once.


PIA23496_hires.jpg

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#2 2020-06-16 10:30:05

tahanson43206
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Registered: 2018-04-27
Posts: 7,616

Re: NASA Mars Sample Return Mission

As a follow up to Post#1, here is an article from late in 2019, before the final decision was made to go with solid rocket motor.

The article describes the competition between hybrid technology and traditional solid rocket motors.

https://www.airspacemag.com/airspacemag … 180973115/

One point that the article makes is that solid rocket motors have been used successfully on Mars to achieve landings for multiple probes.

I would be interested if someone who investigates the history of this decision can find reports on the arguments and how solids ultimately won.

A factor against solids (that I was not aware of) is their vulnerability to cracking in the temperature cycles of Mars.  Apparently a countermeasure is to allocate some solar energy to maintaining the temperature of the motor while it waits on the surface for the sample collection rovers to complete their tasks.

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#3 2020-06-16 17:03:06

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

Re: NASA Mars Sample Return Mission

We have talked about this mission structure for what seems like forever.
Solids in the cold of mars will not have the boiloff issue or the power to create for getting the sample back home.
The trouble with a ready to return rocket for the sample is also how do we land that extra mass as we will want to get more than the rocket to return home as the payload as we need a rover and other tools to make it worth wild.

http://newmars.com/forums/viewtopic.php?id=4465

http://newmars.com/forums/viewtopic.php?id=6983

http://newmars.com/forums/viewtopic.php?id=7616

Then we have the ESA plans as well

https://spaceflightnow.com/2020/04/20/n … f-of-mars/
With estimated cost of $7 billion, the multi-part mission is ambitious, but NASA officials argue it is achievable.

mav_concept1.jpg

The Perseverance rover is launching with 43 sample tubes. Five of the tubes will be blanks — they will not be filled with Martian samples — to help scientists analyzing the specimens sort out what molecules came from Mars, and what originated on Earth.

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#4 2020-06-16 17:55:22

tahanson43206
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Registered: 2018-04-27
Posts: 7,616

Re: NASA Mars Sample Return Mission

For SpaceNut ...

I tried to find previous work on this topic, but got so many results back with the searches i tried that it seemed hopeless.

I would be happy to see you move this set of three posts to one of the previous ones.

The intention of Post #1 was to report on what appears to have been a decision finalized to use solid rocket motor technology for the return vehicle.

Thank you for finding and showing those previous topics.

If you can move the new posts to a topic that is about the NASA return mission, I think that might be better.

The European project deserves its own topic, I would think.

Interesting (to me at least) that one of the earlier posters complained that the MSR would be delayed to 2022 with all the foot dragging.

That prediction looks pretty accurate << grin >>

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#5 2020-06-16 19:25:54

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

Re: NASA Mars Sample Return Mission

GW is the expert when it comes to solids me I am just an Estes rocketeer from when I was building them as a teen.
Single stage to multiple stages with parachutes and camera's to capture at altitude shots/ A few times the rocket was lost to wind, trees, and yes spiraling to the ground ending up like a dart in the lawn.

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#6 2020-11-11 19:04:53

tahanson43206
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Registered: 2018-04-27
Posts: 7,616

Re: NASA Mars Sample Return Mission

Here's an update on the sample return effort ...

https://www.msn.com/en-us/news/technolo … d=msedgntp

NASA is moving swiftly to bring Mars samples back to Earth
Mike Wehner  1 day ago

I would imagine trying to solidify as much as possible during the current administration is a factor in reported speedy efforts.

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#7 2020-11-11 23:22:19

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,622
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Re: NASA Mars Sample Return Mission

I missed seeing this thread until now.  Interesting. 

Two solid motors then a liquid RCS system.  Might work,  or it might not be accurate enough to rendezvous,  unless they add more RCS.  Dunno. 

The way the Minuteman missile had a 100-yard CEP halfway around the world was not the 4 solid stages,  it was the hydrazine-fueled warhead bus that could tailor the end-of-boost trajectory quite precisely. The 4 solid stages gave you instant launch response time.  The liquids never could.

The extreme cold could be a problem unless they consult with some tactical motor designers.  Never get there with PBAN binder.  The big motor boys don't deal with extreme cold (or heat) because their products are kept in nice cozy silos.  Underground,  in a sub,  makes no difference. Cozy.  Not extreme.  (And the +29 F that killed shuttle Challenger is NOT extreme!)

The tactical boys do deal with extremes,  routinely.  -65 F to 145 F (-54 C to 63 C) is mil spec.  We did it using HTPB or CTPB binders,  and the ability to routinely build and analyze finite element grain stress models in 2-D or even 3-D for every single design,  and that was long before there were ever any desktop computers!  There is a glass transition temperature down around -70 to -100 F with binder materials.  You simply cannot go that low.  Must heat if exposed to that.

You can relieve a lot of the cold shrinkage stress if you don't do a case-bonded grain design. But such are NOT spherical motors! And the grain mounting design is much more complicated.  There is such a thing as a stress-relieving liner,  which was used for end-burners that had to go to -65F.  Took effort to develop,  took effort to build in production,  but it was worth it.  Otherwise,  in a more conventional internal-burning grain design,  the bore reduces the stresses at least a little,  and full length slots do even more.

GW

Last edited by GW Johnson (2020-11-11 23:33:12)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#8 2020-11-22 16:48:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

Re: NASA Mars Sample Return Mission

Report on the Construction and Operation of a Mars In-Situ Propellant Production Unit
Contains the Sabatier reactor diagram which this contains....
The prototype used bottle gasses but to do this on mars requires.
Sabatier reactor, which operates at about 0.8 bar (Denver ambient) pressure and 250 Centigrade, to form CH4 and H2O vapor.
The electrolyser requires about 160 W, in the form of 4 V, 40 A DC power.

The group that has gone forward with this has a much lower mass and power levels to achieve the goal of making fuel insitu mars.

A Comparison of Methods for the Mars Sample Return Mission

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#9 2020-12-06 22:11:21

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

Re: NASA Mars Sample Return Mission

Same image for this article
Independent Review Indicates NASA Prepared for Mars Sample Return Campaign

The MSR campaign will require three advanced space vehicles.

The first, NASA's Mars 2020 Perseverance rover, is more than halfway to Mars following launch in July. Aboard Perseverance is a sophisticated sampling system with a coring drill and sample tubes that are the cleanest hardware ever sent to space. Once on Mars, Perseverance aims to cache rock and regolith samples in its collection tubes.

It then would leave some of them on the Martian surface for an ESA-provided "fetch" rover to collect and deliver to a NASA-provided Mars Ascent Vehicle, which then would launch the samples into orbit around Mars.

An ESA-provided Earth Return Orbiter would then rendezvous with the samples in orbit around Mars and take them in a highly secure containment capsule for return to Earth in the 2030s.

"Mars Sample Return is something NASA needs to do as a leading member of the global community," said NASA Administrator Jim Bridenstine. "We know there are challenges ahead, but that's why we look closely at these architectures. And that's why in the end, we achieve the big accomplishments."

Sample return is a top priority of the National Academies' Planetary Science Decadal Survey for 2013-2022, and NASA has worked to mature the critical capabilities and overall MSR concept for the past three years.

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#10 2020-12-19 20:15:22

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

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#11 2021-06-05 20:45:16

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,345

Re: NASA Mars Sample Return Mission

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