Author Topic: First manned mission to Phobos  (Read 30996 times)

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #60 on: 09/30/2010 09:32 am »
I finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:
http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2

I think it could be adapted to Phobos. The issue I have with NEO missions is they are unique, visit once affairs. That makes them pretty much flags and footprints.

Phobos or Deimos is a destination that can be visited every 2.2 years, so long duration infrastructure can be built up with SEP delivered modules.

Offline MickQ

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Re: First manned mission to Phobos
« Reply #61 on: 10/07/2010 05:34 am »
I have been thinking for some time that a major impact event in Mars younger days may have been responsible for a lot of things.  Imagine an asteroid striking the planet at what is now the Hellas Basin.  This pushed the core of the planet so hard that it bulged out the other side creating Tharsis and the big volcanoes.  Phobos and Diemos couold be ejecta fron this event.  This could also account for Mars elongated orbit.

Anyone ???

Mick.
Given the decay in their orbits, one would surmise that the impact was fairly recent (~100 million yrs?) and not early solar system. To create the Tharsis bulge would have been like making Earth's moon.

If Phobos is from Mars, it may have less water and hydrocarbons. However, it could be a composite body - it really does a need a manned visit.



Alex.  I agree.  Phobos should be a priority target.  I think it was Kkattula who recently posted that it is essentially a NEO with a great view.  A perfect place for an outpost to conduct teleoperated research of Mars as well.

Mick.
And:
- It can be reached every 2.2 years. NEOs with low delta V will have infrequent access opportunities.
- With Mars / Earth aero capture, delta V requirements are low - about 1.2km/s from Earth Moon L1
- A SDHLV (e.g. Jupiter 246) with SEP transfer stage can put 50 tons on Phobos.

A couple of months ago I became a fan of "Phobos Direct". Ignore Mars and set up a permanent, substantial base on Phobos. Four SEP cargo flights per year deliver 200 tons of supplies every year. Once the base is up, with ISRU and fuel production, exploring, and then settling Mars is "relatively" easy.

Is "Phobos Direct" an actual mission study/proposal or just an idea ?

Mick.

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #62 on: 10/07/2010 09:56 am »

Is "Phobos Direct" an actual mission study/proposal or just an idea ?

Mick.
Sadly just an idea - unless I consider my notes and spreadsheets a mission study :)

Offline MickQ

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Re: First manned mission to Phobos
« Reply #63 on: 10/08/2010 07:30 am »

Is "Phobos Direct" an actual mission study/proposal or just an idea ?

Mick.
Sadly just an idea - unless I consider my notes and spreadsheets a mission study :)


You have to start somewhere.  Care to share what you've done ???

Mick.

Offline Warren Platts

Re: First manned mission to Phobos
« Reply #64 on: 10/08/2010 07:47 am »
I finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:
http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2

Thank you for actually posting the link!

Quote
I think it could be adapted to Phobos. The issue I have with NEO missions is they are unique, visit once affairs. That makes them pretty much flags and footprints.

Phobos or Deimos is a destination that can be visited every 2.2 years, so long duration infrastructure can be built up with SEP delivered modules.

Yeah, but the preferred mode these days seems to be the neverending pursuit of "firsts".... Thus NEO's are perfect for this, they only come around once a decade, so they're "cheap", and there's no denying that each new one is a new first....
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline alexw

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Re: First manned mission to Phobos
« Reply #65 on: 10/08/2010 08:15 am »
I finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:
http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2
Thank you for actually posting the link!
pdf at:
http://nasawatch.com/archives/2010/09/human-explorati.html
    -Alex

Online Lampyridae

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Re: First manned mission to Phobos
« Reply #66 on: 10/08/2010 08:21 am »
I finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:
http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2
Thank you for actually posting the link!
pdf at:
http://nasawatch.com/archives/2010/09/human-explorati.html
    -Alex


Thank you. scribd.com was taking its sweet time!
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Offline alexterrell

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Re: First manned mission to Phobos
« Reply #67 on: 10/08/2010 03:24 pm »

Is "Phobos Direct" an actual mission study/proposal or just an idea ?

Mick.
Sadly just an idea - unless I consider my notes and spreadsheets a mission study :)


You have to start somewhere.  Care to share what you've done ???

Mick.
It's all in Excel, rather than Word, but the numbers are attached.

The main premise is a 1MW VASIMR based upper stage with that means an SLS launch can deliver 50 tons to Phobos.

The sheet "Schedule" shows arrivals (Column C) at Phobos, by Quarter. This assumes a quarterly launch, but I haven't yet accounted for bunching - e.g Hohmann transfer is every 2.25 years (9 quarters) but I think the SEP tugs will arrive out of phase with this.

Every 1MW VASIMR arriving joins a solar tower (at the pole) to provide 400KW of power)

So in quarter 12, the first crew arrive (on ESS1). By then there is a significant base (550 tons) capable of ISRU and fuel production. (They also have emergency return boosters, in case they can't get rocket production going).

The ISRU fuel plant converts Kerogen and Water into LOX and Kerosene (or methane if easier). Then crew ships (and later Mars ships) are fueled up on Phobos. Crew ships then go from Mars to Earth Moon L1 and back on this fuel load.

Mars exploration starts in Q31 (pretty late).  Reusable cargo ships are refuelled on Mars, and send supplies down and return with Argon (which is used to send VASIMRs back to Earth with Water (for a L1 fuel depot).

Habitats are made of inflatables and covered with regolith (or inflated in the regolith). This provides the heavy shielding, so you can get a lot of volume for not much Earth mass.

From Q40, larger transport ships (100 passengers, ESS11 - 20) are substantially built at Phobos, using manufacturing equipment, moulds, CNC etc brought from Earth.

The sheets Missions and Mars Access are delta v calcs which need a bit more explanation.

Offline Patchouli

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Re: First manned mission to Phobos
« Reply #68 on: 10/08/2010 03:44 pm »
I agree that astronauts can probably adapt to ~5-10rpm, which should be good enough for Mars-level gravity in something like a Bigelow Sundancer module. Heck, you could just build it after you orbited the module, inside the module. You could have an artificial-gravity section of the module where sleeping, exercising, and perhaps other activities that could benefit from artificial gravity (like fixing or making something... most rapid manufacturing techniques rely on gravity). Also, if even idle activity in artificial gravity is found to be helpful, computers and desks could be placed in the artificial gravity section.

The ring wouldn't need to be sealed at all (in fact, it would best not be sealed), and should be able to be spun-down at any time. Any structural considerations should be handled by the structure of the ring.

Just an idea.

EDIT: Part of the benefit of this idea is that the whole artficial gravity mechanical system would be inside a pressurized environment, and thus could be fixed mid-flight using conventional hand tools without a difficult and risky EVA.

Current BA 330 design is too small to accommodate an internal centrifuge. It *could* be done, with 6RPM you are looking at 0.12g, with 8, 0.2g. I would suggest a 10m diameter hab as a minimum (2001 Discovery centrifuge size). At these sizes, too *low* an RPM causes problems with Coriolis forces and walking speeds. But perhaps these aren't as big problems as we think they are.

A couple of rings of fluid around the rotation axis should keep instabilities down.

Gasbarri P., Teofilatto P. (2009) Fluid ring dampers for artificial gravity spacecraft. Acta Astronautica (64), 1286-1292

With a vehicle like SLS you can lift the type of solutions proposed for the Saturn V.
I think the Rigid Station 2 would be the perfect hab for a Phobos mission.
Use Bigelow's or LLC Dover's inflatable technology the hexagonal rim can be replaced with for a more desirable circular one.
http://www.astronautix.com/craft/selation.htm
« Last Edit: 10/08/2010 03:47 pm by Patchouli »

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #69 on: 10/08/2010 05:20 pm »
The stations from the 60s such as Rigid Station 2 don't really provide enough radiation protection - they were designed for LEO. The Bigelow devices are designed to provide protection, but weigh too much to get anything with artificial gravity.

On Phobos, with loose regolith, you can inflate BIG devices, and cover them in regolith. But the outer pressure vessel can't rotate.

You could of course inflate Rigid Station 2 inside a lightly pressurised balloon (0.01 bar would do it), which would hold the regolith off.

Or go for the design I showed in Reply #20. That can fit in Jupiter 246.

Offline Cinder

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Re: First manned mission to Phobos
« Reply #70 on: 10/09/2010 01:19 am »
Bigelow have said they've got designs in the works much larger than BA-330.
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Offline alexterrell

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Re: First manned mission to Phobos
« Reply #71 on: 10/09/2010 07:51 am »
Good to hear that - I'm sure they have plans for something in the 70 ton class.

However, Bigelow always has to worry about shielding. So even 70 tons is probably limited to about a BA-1000 (i.e 1,000m3 - still bigger than ISS).

If you can use regolith as shielding, then 70 tons limits you to about 500,000m3 (with current materials).

Offline douglas100

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Re: First manned mission to Phobos
« Reply #72 on: 10/09/2010 10:03 am »
From alexterrell:

Quote
The ISRU fuel plant converts Kerogen and Water into LOX and Kerosene (or methane if easier). Then crew ships (and later Mars ships) are fueled up on Phobos. Crew ships then go from Mars to Earth Moon L1 and back on this fuel load.

It might be unwise to make this an important part of your architecture until we have a better idea of what Phobos is actually made of.
Douglas Clark

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #73 on: 10/09/2010 12:07 pm »
From alexterrell:

Quote
The ISRU fuel plant converts Kerogen and Water into LOX and Kerosene (or methane if easier). Then crew ships (and later Mars ships) are fueled up on Phobos. Crew ships then go from Mars to Earth Moon L1 and back on this fuel load.

It might be unwise to make this an important part of your architecture until we have a better idea of what Phobos is actually made of.

That would be true if I (or NASA) were going to spend serious money on this. Phobos is probably a highly desirable location, which is all the more reason to send some probes there.

If Kerogen is not present, but water is, then then ISRU needs to focus on water and LOX/LH2 propellent.

Kerogen would be nice to manufacture carbon fibres and various plastics. If it's not there, then metal working will need to move up the agenda (though CC asteroids are poor in Al, rich in Fe).

One scenario is that Phobos is resource rich, but buried by 100s of metres in dessicated carbon free dust.

Offline A_M_Swallow

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Re: First manned mission to Phobos
« Reply #74 on: 10/09/2010 11:51 pm »
One scenario is that Phobos is resource rich, but buried by 100s of metres in dessicated carbon free dust.

Then we would need to know what the dust is.  With a bit of thought practically anything that burns can be turned into rocket fuel, although the Isp may be low.  If the material can be converted into a solid say by pressure or melting then it can be used for construction purposes.  Phobos is in a shallow gravity well so even non-reactivate asbestos could be used as say a heat shield on the Mars landers.

Offline HappyMartian

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Re: First manned mission to Phobos
« Reply #75 on: 10/10/2010 05:19 am »
One scenario is that Phobos is resource rich, but buried by 100s of metres in dessicated carbon free dust.

Then we would need to know what the dust is.  With a bit of thought practically anything that burns can be turned into rocket fuel, although the Isp may be low.  If the material can be converted into a solid say by pressure or melting then it can be used for construction purposes.  Phobos is in a shallow gravity well so even non-reactivate asbestos could be used as say a heat shield on the Mars landers.


A_M_Swallow, I like it. If Phobos can supply lots of propellant, and you have a big reusable space tug, you might consider gluing or sintering the Phobos dust together into a very large heat sheild. Doing that would be an early high priority ISRU activity. The tug puts the payload and built on Phobos very large heat shield into a interception orbit with the atmoshere of Mars. Then the tug returns to Phobos for refueling and a new payload and very large heat shield... It sounds good.

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