[FPSPACE] Phobos First !!

David Portree dsfportree at hotmail.com
Sun Apr 26 13:47:49 EDT 2015


John:
Thanks for the info. I think we have to assume that we've done a lot of education and our culture has changed to permit "an approach free of constraints imposed by reality" or you might as well change jobs and become a rover wheel designer (I hear they need some of those). That said, I admire the folks in the piloted program who try to keep the flame alive, as the old slogan went.
I base my Variable-G ideas on a bunch of old studies - you know me, I dig into all the past work. I think a single truss is simplest to build but hardest to steer. Hence, I prefer a wheel-within-wheel structure with each wheel simulating a different acceleration level/spin rate of interest. Mars would be outermost, moon intermediary, micro-grav at the center. Fluid moving around in pipes and tanks would trim the spin to prevent wobbles. Crew would live on different levels for extended periods to test equipment , performance, health maintenance, etc. The wheels would not have to be continuous full-diameter toroids - that would be overkill. 
Moving this thing around using chemical rockets would indeed by challenging, but I expect we'll have available SEP to give it a push, then we'll cleverly use the gravitational geometry of the Earth-moon-Sun system to get it to L points, high lunar orbit, near-Earth heliocentric orbits, etc. Orion would enable crew to visit the Variable-G station as it moved around in the Earth-moon-Sun system. It could be quite an interesting voyage for crews, with close Earth and close lunar flybys, visits to SEL1 and SEL2, heliocentric orbits nearly matching that of Earth, etc. One could also put it into in various lunar cycler and semi-cycler orbits. All that would happen after the bulk of the basic hypogravity research was completed.
If lunar gravity were enough, then an interplanetary spacecraft based on the best features of the station would be sized for lunar gravity. If Mars gravity were preferred , then it would be sized for Mars gravity. 
We've become trained to limit our aspirations by years of abuse and neglect. I don't see why we should succumb to a kind of mass "Stockholm Syndrome" and buy into those limitations. If we're going to do that, we might as well come clean about our likely future and switch to full-on robots. Spaceflight - even piloted spaceflight - is cheap compared with just about anything else we do. Plus, despite some setbacks, we've been brilliant in space. Let's brag (another word for "educate").
dsfp
David S. F. Portree
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CC: fpspace at lists.friends-partners.org
From: jbcharle at gmail.com
Subject: Re: [FPSPACE] Phobos First !!
Date: Thu, 23 Apr 2015 07:22:12 -0500
To: dsfportree at hotmail.com

David, you have nicely described an approach free of constraints imposed by reality. We are doing our best to match it, constrained as we are. 
NASA Human Research Program agreed to the first one year mission only if it is part of a program of five more. Of course, the Russians want to see how the first one goes before they commit to more. There's a year lost. We might still get all five done before the end of ISS use by NASA in 2024. They need to be at intervals, and there are complexities in planning that provide more constraints (there's that word again).
One year was not chosen to match any mission design but is part of a progressive increase in duration. Obviously longer durations won't be on ISS in the HRP plan described above. But let's see what the future holds. 
We are using the 1YMs to validate our knowledge and countermeasures developed on 6-month missions. If they work on 1YM then we assume they will keep working. If not then the incremental risk is not too large to try something new. 
The VGRF idea was proposed many times, including at a workshop I attended in 1987 iirc. NASA HRP is taking another run at AG but against a lot of high-level inertia. Stay tuned. 
I doubt any large vehicle can double as a LEO space station and an exploration vehicle. (Even the Apollo CSM had differences between its lunar and Skylab versions.) Design constraints (!) dictate some differences. But, Elon Musk is pursuing new and expensive paradigms. Let's see if he is interested. 

Yes, I still believe countermeasures for weightlessness will work for hypogravity too. (How could it be otherwise?) But they may be overkill. Hypogravity experience can indicate where efficiencies might be possible. But absence of hypogravity experience is not a show stopper. 

John CharlesHouston, Texas
On Apr 22, 2015, at 21:05, David Portree <dsfportree at hotmail.com> wrote:




I can't help wondering whether we're barking up the wrong tree here. How many one-year missions are planned? It would seem necessary to do several (5? 10?) to get a decent baseline. From what I've read, we have very little data beyond six months (Polyakov, mainly) and nothing for women. Plus, a year isn't going to be enough to go many places. Split/sprint could do ~one-month at Mars with six months each way (and a free-return option), though I wonder how many would be satisfied with a one-month Mars system stay. Folks seem to have become enamored of conjunction-class long stays (300-400 days) leading to missions of more than 2 yrs in micro- or hypogravity.
Granted, we have time for one-year and two-year weightless stays before the 2030s Mars expeditions folks talk about. I wonder, though, about how we're going to figure out what happens to people in Mars gravity. You told me once that you expected that weightless problems would continue in Mars gravity at a somewhat reduced rate. Do you feel differently about that now?
And, what if we find after a decade or so that people suffer harm after a year in microgravity? Isn't that a decade lost? It could be longer - and thus more time lost - if we find evidence of longer-term microgravity effects after people return to Earth. 

I really think that the obvious next step is staring us in the face, and that's the variable-gravity space station I keep harping about. If designed properly, it could serve as a prototype artificial-gravity spacecraft and even be moved to various points in the Earth-moon system (EML1 and EML2, for example, to support piloted lunar landing missions and lunar telerobotics, for example). I think we should aim to have it built in a decade so when 2024 rolls around it is ready to take over.
dsfp

David S. F. Portree
author

Email:
dsfportree at hotmail.com
dportree at usgs.gov 
 
Profile:
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http://spaceflighthistory.blogspot.com/





Date: Tue, 21 Apr 2015 03:59:43 +0000
From: jeoberg at comcast.net
To: john.b.charles at nasa.gov
Subject: Re: [FPSPACE] Phobos First !!
CC: dstdba at aim.com; fpspace at lists.friends-partners.org

Good plan, John, and you know I've been following the proposals for a lo-o-o-o-ong time.

As things stand now, how soon could you initiate a repeat 12-month mission to focus on what you learn this time?

How much longer in LEO would any downstream follow-on missions have to be to be worth the effort?

J




From: "John B. Charles (JSC-SA211)" <john.b.charles at nasa.gov>
To: "dstdba" <dstdba at aim.com>
Cc: fpspace at lists.friends-partners.org
Sent: Sunday, April 19, 2015 3:23:48 PM
Subject: Re: [FPSPACE] Phobos First !!

Speaking as one of the people who planned the current one year (almost) mission, I can say that it is primarily intended to test whether we are as smart as we think we are based on what we learned from 15 years of 6-month (plus or minus) ISS expeditions. Previous Russian experience shows that there are no "brick walls" out to 14 months. I don't think we will see them even on 30-month Mars missions. But crewmember effectiveness and efficiency will need to be protected by treatments and "countermeasures" now in development and testing on ISS. So, we are evaluating them with this longer mission, hoping to find any "oops" and "uh oh" sooner rather than later. 
 
 John CharlesHouston, Texas
 On Apr 19, 2015, at 11:44, dstdba <dstdba at aim.com> wrote:
 
I thought one purpose of year-long stays on ISS was to ascertain that a voyage to thevicinity of Mars and back would not require artificial gravity? A landing on the surfaceof Mars would be a different story, of course, due to the likely need for heavy work. Science alone does not warrant an expensive manned visit to an asteroid. For the sakeof preparing us for the deflection of one too close for comfort, we need to know itsproperties. Asteroids come in many sizes, shapes, and flavours. Therefore the onlymeaningful voyage is to one that actually needs deflection! Were a NEA detection program set up with the objective to map the orbits of all Near Earth Asteroids with diameters greater than 50m, the expected number of such objectssuggests that at least one of those found will be on a collision course with Earth. There is a high probability that the effort of paying an early visit to such a object would be cost-justified! --Jens Kieffer-OlsenSlagelse, Denmark Fra: David Portree [mailto:dsfportree at hotmail.com] 
 Sendt: 15. april 2015 01:37
 Til: Chris Jones; fpspace at lists.friends-partners.org
 Emne: Re: [FPSPACE] Phobos First !! I think these advisors are missing something important - that the asteroid mission was selected in part because it would not split the community. We have serious moon and Mars advocates, and they are at loggerheads, but not so much serious asteroid advocates (speaking of piloted missions, here). Of course, there are plenty of good reasons not to send humans to asteroids and ARM has evolved into something ludicrous, but advice from a high-level group that just assumes that Mars is widely accepted as the next goal for human spaceflight cannot help but be polarizing.
  
 We actually do need interim steps before we land humans on Mars, but going all the way to Mars and inserting into orbit kind of misses the point. We need to work out how much artificial gravity is enough, for one thing, which is why I advocate for a variable-gravity space station as a next step after ISS. It's a good transitional step because the variable-gravity station could serve as a prototype for a piloted artificial-gravity interplanetary spacecraft. Astronauts on board would study themselves during progressively longer stays under lunar gravity, Mars gravity, and perhaps some level between Mars and Earth gravity. 
  
 Small bodies are turning out to be difficult places to work. Given the record so far, there's good reason to suppose that ARM would not be able to retrieve a boulder from an asteroid. Similarly, it seems likely that surprises will await us on Phobos and Deimos. Osiris-REX and Hayabusa 2 might have some things to teach us that could lead us to rethink how we would conduct robotic Phobos and Deimos missions. Personally, I'd like to see an asteroid mission that bumps around on the surface of kilometer-scale body and purposely stirs things up by drilling, setting off explosives, shooting projectiles into the surface, planting an anchor and trying to pull away, etc.
  
 Always dreaming!
  
 dsfp
  
 
 
 David S. F. Portree
 author
 
 Email:
 dsfportree at hotmail.com
 dportree at usgs.gov 
 
 Profile:
 http://astrogeology.usgs.gov/people/david-portree 
  
 Blogs:
 http://dsfpll.blogspot.com/
 http://spaceflighthistory.blogspot.com/
 
 
 
 
  > Date: Mon, 13 Apr 2015 15:19:25 -0400
 > From: clj at panix.com
 > To: fpspace at lists.friends-partners.org
 > Subject: Re: [FPSPACE] Phobos First !!
 > 
 > On 4/13/2015 7:46 AM, dstdba wrote:
 > > In all probability Phobos is a captured asteroid, so no great deal
 > > really.
 > >
 > > And certainly common sense dictates that the sequence of places in
 > > the solar system for humans to visit is Moon, Martian moons, Mars.
 > 
 > I've certainly heard the theory about Phobos and Deimos being captured
 > asteroids, although it's somewhat hard to explain how they ended up in
 > low-eccentricity near-equatorial orbits as a result. I also agree
 > either or both Martian moons are a good precursor mission for humans to
 > undertake prior to a Martian landing, but I don't reject out of hand
 > visits to NEOs, though I'd rather see more robotic missions beforehand
 > (including close flybys or orbits, landings, and potentially more sample
 > returns).
 
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