Realistic, near-term, rotating Space Station

[LMT]

SpaceX has to build a base on Mars before creating a settlement. At least build a fuel depot. The crews sent to Mars to setup these facilities will show whether or not there are any short term medical issues for humans living in 0.38 g.

How do you timebox "short term" there, for Mars stay and also for flight duration?

There is no requirement for AG to get a vehicle FAA certified and NASA won't care about AG. Look at their recent Mars mission plans. None of them have AG.

I did look at NASA's plans, or at least Mars DRA 5.0.  DRA5 talked quite a bit about AG need, and I noted this recently.  DRA5 does not say, "NASA won't care about AG."  To the contrary.  But has NASA's view changed dramatically since 2009?

FAA certification follows NASA's human rating for the spacecraft per its specific mission requirements, as far as I know, though I could be wrong.  (Thinking of FAA safety approvals, launch licenses, etc.)  Hence an apparent need for long-duration AG testing prior to crewed Mars launch. 

Can you say more about FAA certification for crewed Mars launch absent NASA's human-rating approval?

[RonM]

SpaceX has to build a base on Mars before creating a settlement. At least build a fuel depot. The crews sent to Mars to setup these facilities will show whether or not there are any short term medical issues for humans living in 0.38 g.

How do you timebox "short term" there, for Mars stay and also for flight duration?

There is no requirement for AG to get a vehicle FAA certified and NASA won't care about AG. Look at their recent Mars mission plans. None of them have AG.

I did look at NASA's plans, or at least Mars DRA 5.0.  DRA5 talked quite a bit about AG need, and I noted this recently.  DRA5 does not say, "NASA won't care about AG."  To the contrary.  But has NASA's view changed dramatically since 2009?

FAA certification follows NASA's human rating for the spacecraft per its specific mission requirements, as far as I know, though I could be wrong.  (Thinking of FAA safety approvals, launch licenses, etc.)  Hence an apparent need for long-duration AG testing prior to crewed Mars launch. 

Can you say more about FAA certification for crewed Mars launch absent NASA's human-rating approval?

Short term would be an entire tour of duty for a crew. Several months to Mars, over two years on the surface, and several months back to Earth. Plenty of time to determine the health risks of staying in a low gravity environment.

With mice, a couple of years on Mars would result in several generations. Valuable primarily research on long term effects. If birth defects in mice turn up, it's time to reconsider settlement.

What's changed since DRA 5.0? Several years of data from ISS. BTW, spending less than a page out of eighty pages isn't quite a bit.

FAA is concerned with safety during takeoff and landing, not the entire mission.

As long as NASA astronauts are not on the mission, SpaceX won't need NASA certification.

WE won't need a spin gravity research space station unless there are problems found on the Mars missions or somebody decides they want to start building orbital colonies.

[LMT]

Integrating Richie-class AG into a First SpaceX Mars Mission

Just to pull a few thoughts together, I roughed out one way in which a Richie-class ITS space station might be integrated into a first crewed SpaceX Mars mission, launching notionally in 2024.  Brief notes, just for discussion.

Mission context:

Casey Handmer has estimated ITS capability for a single-window Mars mission lasting ~ 425 d. 

Being stranded on Mars by inopportune launch windows is basically the worst. So I created a map of all the Earth-Mars (with free return) and Mars-Earth launch windows over the next decade or so. It shows the dV needed on any given launch day and for any given flight duration.

Here's an example [red line] of how a sufficiently advanced @SpaceX BFR could manage a flight to Mars every launch window, with a 28 day turnaround on Mars. Just catching the closing edge of the return window will require solar electric propulsion. Easier than doubling BFR production rate.

Gray lines allow projection of flight duration back to the central timeline, demarcated in both Earth and Mars years. dV is calculated assuming a low orbit trans-planetary injection to exploit the Oberth effect, and on this graph shows what is needed beyond escape (C3=0).

Application:



1.  Late 2024: launch of ITS pair to LEO.  ITS-1 is crewed (<10), with no water shielding.  ITS-2 is a lighter, uncrewed lifeboat with min provisions and min hw for emergency use.

2.  Burn from LEO.

3.  Because ITS-2 is lighter, it has remaining propellant after (2.).  It shares propellant with ITS-1.

4.  Second burn, to Mars.

5.  Richie-class .38 g in flight, possibly with periods of (unpleasant) 1 g training, to partially address low-g issues.

6.  Mars EDL, 1-month stay, launch to LMO.

7.  ITS-2 shares propellant with ITS-1.

8.  Second burn, to Earth.

9.  .38 g in flight

10.  Late 2025: Earth EDL.

Propulsion note:

Handmer sees need for solar electric propulsion (SEP) at the "closing edge of the return window".  Additional propellant from ITS-2 would plausibly drop SEP requirement.  This does require $ for a second ITS craft, but that craft offers lifeboat and AG, in addition to SEP-substitute propellant.  Also, arguably SEP for a large spacecraft entails considerable challenges and $, so you'd avoid SEP if you could, at least on early Mars flights.

Schedule:

If the 2-ITS rotating space station began .38 g AG tests in 2022, testing for this first Mars mission would complete in 2023.  Assuming good result, at that time NASA could give human-rating approval for ITS, for just this 425-day mission.  The test system could be refurbished and repurposed for the 2024 mission, to reduce net cost.

Testing of other, multi-year mission profiles would continue apace.  All AG tests would complete prior to return of the first mission crew at the end of 2025.  Again assuming good result, at that time NASA could give its human-rating approval for ITS multi-year missions; and such a mission could launch in late 2026.  Here again, test system components could be refurbished and repurposed for mission use.

[punder]

Yes. Exactly the kind of experiments that should have been done long ago. Obvious to me, not so obvious to NASA. If only they had listened to punder, that anonymous schmuck on the Interwebs.   

Ah well, necessity is the mother of invention.  Maybe need will cross an organizational threshold, not too far down the road.

The ship has sailed. Experiments in 1/6 g biology will be conducted first on the Moon. 1/3 g experiments will be conducted on the Moon or Mars itself. Too late; the responsible agency didn't get its s!?t together in time.

"The ship has sailed"?  Can you expand on that?  The options, timeframes and rationales aren't entirely clear to me.

Meaning an opportunity was lost for want of timely action. In an earlier post I opined that, were NASA to catch a sudden windfall of funding and a complete plan for a variable-AG spacecraft, it would take them far longer to design, develop, integrate, and launch the thing than it will take Musk or Bezos to land crew on the Moon (or possibly even Mars) where low gravity effects will be explored in situ.

Predictions are hard, especially about the future! But I am very confident humans will be back on the Moon by 2028. That means, if NASA started right now, they'd have a decade to field a VG facility before it was overtaken by events.

Orion was begun in 2010. Although a boilplate flew in 2014, an operational version won't fly until 2021, probably. Decade. Not counting the several years of Constellation CEV development that fed directly into Orion. This is a beefed-up Apollo capsule, not a big rotating crew-rated gizmo with which NASA has no experience.

SLS was officially started in 2011. Was supposed to save a crapload of time and money by using Shuttle tanks, engines, and SRMs. Won't fly until 2021, probably. NASA couldn't take 30-year-old tech and turn it into a working launcher in less than a decade.

Thus, if Santa skidded onto the JSC lawn tomorrow and handed over $10B with the stipulation that it would go up in smoke if not used for a VG spacecraft, NASA would take at least a decade to launch one. Long after (my spidey-sense says) SpaceX and/or BO employees are frolicking amongst the craters.

[Coastal Ron]

Short term would be an entire tour of duty for a crew. Several months to Mars, over two years on the surface, and several months back to Earth. Plenty of time to determine the health risks of staying in a low gravity environment.

Not only is it 2 years in 1/3 gravity, but it's also 2 years in an environment where humans will be able to move around a lot more than if they are on an artificial gravity spaceship or space station. We already know that exercise is important to warding off the effects of 0G, so being on a planet with lots of physical work to do will be a good test of how exercise can ward off the negative effects (if any) of 1/3 G.

With mice, a couple of years on Mars would result in several generations. Valuable primarily research on long term effects. If birth defects in mice turn up, it's time to reconsider settlement.

Only if we intended to colonize Mars with mice... 

What's changed since DRA 5.0? Several years of data from ISS. BTW, spending less than a page out of eighty pages isn't quite a bit.

Agreed. There is a difference between a mention and an initiative.

As long as NASA astronauts are not on the mission, SpaceX won't need NASA certification.

Airlines, cruise ships and trains don't require NASA certification to transport NASA employees, so I think it's possible that the U.S. Government could buy passage on a SpaceX BFS to Mars without NASA needing to be involved.

WE won't need a spin gravity research space station unless there are problems found on the Mars missions or somebody decides they want to start building orbital colonies.

One other "job" for artificial gravity space stations is to act as a place or refuge and reconditioning for humans as they are either on a distant planet (i.e. go up to the local space station for refuge and reconditioning) and in orbit around Earth for humans coming back from low-gravity destinations and need to recondition their bodies in anticipation of returning to the surface of Earth.

Of course the big question is "when" those needs have to be addressed, and "who" will pay for them?

[LMT]

SLS was officially started in 2011. Was supposed to save a crapload of time and money by using Shuttle tanks, engines, and SRMs. Won't fly until 2021, probably. NASA couldn't take 30-year-old tech and turn it into a working launcher in less than a decade.

Now go easy on 'em, punder.  Remember, they also had to turn reusable engines into disposables.  That takes time, you know.

[LMT]

What's changed since DRA 5.0? Several years of data from ISS. BTW, spending less than a page out of eighty pages isn't quite a bit.

Agreed. There is a difference between a mention and an initiative.

btw, that was an extract.

Edit/Lar: Snark removed.

[Cherokee43v6]

Ya know, one of the BEST drivers of development of an artificial gravity station in Earth orbit would be if colonist  on Mars discovered that there were extensive health BENEFITS to living in 1/3rd gravity.

In that case there would be people who would not want to 'rough it' on Mars who would be all about spending money on an Earth orbit 1/3rd G spa.

[RonM]

What's changed since DRA 5.0? Several years of data from ISS. BTW, spending less than a page out of eighty pages isn't quite a bit.

Agreed. There is a difference between a mention and an initiative.

btw, that was an extract.

Does L2 subscription get us posters who read the docs they talk about?

L2 is a great source for insider information, but DRA 5.0 docs are online.

I found DRA 5.0 Addendum 2 and it's got several pages on AG. This update was written in 2014. Its nearly 600 pages overall and about 60 MB. Google it and take a look.

Still no money for a NASA AG station, but at least a few people at NASA are still thinking about it.

[LMT]

I found DRA 5.0 Addendum 2 and it's got several pages on AG. This update was written in 2014. Its nearly 600 pages overall and about 60 MB. Google it and take a look.

I gave the link & extract 4 days ago, and reminded you today.

Edit/Lar: snark removed.

So how about that Bigelow Olympus AG station Roy_H was talking about?  Got some opinions on all that?

[Coastal Ron]

So how about that Bigelow Olympus AG station Roy_H was talking about?  Got some opinions on all that?

I know it's advantageous to consider using existing or potentially near-term space hardware for potential space projects since could be major cost savings, but when it is suggested that hardware designed for 0G be used for artificial gravity systems, to me that is fraught with many structural issues.

My suggestion would be to start with a clean-sheet design and THEN see if there are existing hardware that is appropriate to use.

For instance, without considering reusing any existing hardware, and with the freedom to design anything, what would be the smallest possible rotating space station that would allow for either just micro-gravity research, or possibly be big enough to be a permanent platform supporting human activity in space?

[RonM]

I found DRA 5.0 Addendum 2 and it's got several pages on AG. This update was written in 2014. Its nearly 600 pages overall and about 60 MB. Google it and take a look.

I gave the link & extract 4 days ago, and reminded you today.

And your googlit post got NSF 'likes'.      

So how about that Bigelow Olympus AG station Roy_H was talking about?  Got some opinions on all that?

Oops, I didn't notice the link to Addendum 2. I admit I skim though long posts. Lots of people do that.

Bigelow modules could work for AG stations. Two issues would be orientation based on the structure and what launch vehicle would be used to deploy the modules. Depending on the design, the Bigelow module central core might need to be strengthened. The big benefit of an expandable module is the ability to get a large module to orbit in a smaller diameter faring. Great if using NG or FH, but not really needed if using BFR.

For near-term stations, a couple of Bigelow modules and perhaps a connecting section to increase the radius would be good.

I like the idea of two BFS attached at the nose. Since it looks like SpaceX will be hoisting BFS by the nose with cranes, it shouldn't be difficult to modify them. Also keeps the crew decks in the proper orientation. Docking at the aft and spinning adds complications with "dancing on the ceiling" as I believe you pointed out. Maybe rearranging the furniture will give the crew something to do.

[lamontagne]

I'll just throw this in for the sake of argument.  September 2014, time flies!
Never got to finish it, but I guess there might be some interesting bits.

The modules were somewhat smaller than the full 3100 Bigelow ones, to fit into a Falcon heavy fairing and mass.
Pehaps we should design for a full 150 tonnes BFR load.  That might be interesting?

[lamontagne]

I think there is a real problem with the 2017 model of the BFR solar cells in the nose to nose rotation idea.
To be specific, how do you keep the solar panels from tearing off?

[LMT]

I think there is a real problem with the 2017 model of the BFR solar cells in the nose to nose rotation idea.
To be specific, how do you keep the solar panels from tearing off?

Well, even in the 4-ITS simplified Richie-class config, max AG on solar panels is only .7 g.  That's not especially challenging, is it?  The panel system must withstand higher g-forces in EDL.

Also you need a proper self-storing hub there.  Space cribs should be pack&go portable.   

[LMT]

Short term would be an entire tour of duty for a crew. Several months to Mars, over two years on the surface, and several months back to Earth. Plenty of time to determine the health risks of staying in a low gravity environment...

WE won't need a spin gravity research space station unless there are problems found on the Mars missions or somebody decides they want to start building orbital colonies.

Biomedical Ph.D. mikelepage, do you have a comment or anecdote to share wrt RonM's suggestion, maybe amplifying your recent hypothetical?

[mikelepage]

Short term would be an entire tour of duty for a crew. Several months to Mars, over two years on the surface, and several months back to Earth. Plenty of time to determine the health risks of staying in a low gravity environment...

WE won't need a spin gravity research space station unless there are problems found on the Mars missions or somebody decides they want to start building orbital colonies.

Biomedical Ph.D. mikelepage, do you have a comment or anecdote to share wrt RonM's suggestion, maybe amplifying your recent hypothetical?

You don't need to list my qualifications every time mate but thanks for the vote of confidence.  Reading through the thread since I last commented I've been trying to think how best to communicate what I think are a series of not-necessarily-true assumptions. 

On the one hand, you've got a series of beautifully-done renders by Roy_H and lamontagne which at current prices, or even a single-order-of-magnitude reduced launch prices, would obviously cost much more than the ISS to actually build.  Potentially costing more than a Mars program. All the engineers look at that and see a zero-sum game between Mars mission/Moon mission or AG station, and they choose the planetary missions since that will give us partial G data anyway.

On the other hand, you've got people planning multi-year missions to Mars, which assume that the current paradigm of 2-4 hours exercise per astronaut, per day, for one year missions, can be extrapolated out to 2+ year missions.  Because we have no real data for partial G, that is taken to mean we can't have expert opinions about what is likely to happen over extended periods in partial G, so we might as well try it and see what happens.

The problem with this is that that there is likely to be a dose response curve of symptoms in response to zero G and partial G - as there is to most other biological stressors.

Scott Kelly, by his own estimation, took nearly 3 months to return to normal abilities after a year in zero G.  Contrast this with most astronauts who spend 6 months in space, who fully recover in much less time than six weeks (half of three months).  I think it is a perfectly reasonable prediction that the recovery from 18 months of zero G would be much worse again than the recovery from 12 months.

In which case, it may be that partial G is better for us than zero G, but that is not the same as saying there is a "safe level" of partial G.  More likely it's just that the derivative of the increase in symptoms is lower with partial G, but it's still an "exponential" (actually sigmoid) increase in symptoms.

Which brings us back to the original idea that it is probably an unacceptable risk to send people on 2+ year Mars missions without having done some partial G research first (although I wouldn't exclude missions that go and return during the same synodic).  We just have to get more clever with designing a research platform that doesn't cost an arm and a leg. 

All:  Gary Hudson over at the Space Studies Institute (SSI) has been beating the drum for the need of artificial-gee for human spaceflight for years now and I totally agree with Gary that before we establish long term colonies on the Earth's Moon and Mars, we had first find out if humans can breed in and live long-term under 1/6 and 1/3 gee gravity fields.  A good summary of Hudson's approach to finding the answer to these questions is at the below December 2015 YouTube video URL.  In this video Gary lays out a moderately low cost approach to finding the answers to these biological compatibility questions.

https://www.youtube.com/watch?time_continue=10&v=xO1Pvtv_A4k

Best, Paul M.

Relinking this video because the top way to reduce the cost of building an AG research station is to minimise the number of launches, and this is one way of doing that.

Pedantry side note: Can we please stop talking about Mars gravity as "1/3" G?   It's 38.9% of 1G, and it's only become 1/6 and 1/3 G because Lunar gravity is almost exactly 1/6th of G.

[RonM]

Short term would be an entire tour of duty for a crew. Several months to Mars, over two years on the surface, and several months back to Earth. Plenty of time to determine the health risks of staying in a low gravity environment...

WE won't need a spin gravity research space station unless there are problems found on the Mars missions or somebody decides they want to start building orbital colonies.

Biomedical Ph.D. mikelepage, do you have a comment or anecdote to share wrt RonM's suggestion, maybe amplifying your recent hypothetical?

You don't need to list my qualifications every time mate but thanks for the vote of confidence.  Reading through the thread since I last commented I've been trying to think how best to communicate what I think are a series of not-necessarily-true assumptions. 

LMT was trying to use your credentials to support his position. 

On the one hand, you've got a series of beautifully-done renders by Roy_H and lamontagne which at current prices, or even a single-order-of-magnitude reduced launch prices, would obviously cost much more than the ISS to actually build.  Potentially costing more than a Mars program. All the engineers look at that and see a zero-sum game between Mars mission/Moon mission or AG station, and they choose the planetary missions since that will give us partial G data anyway.

On the other hand, you've got people planning multi-year missions to Mars, which assume that the current paradigm of 2-4 hours exercise per astronaut, per day, for one year missions, can be extrapolated out to 2+ year missions.  Because we have no real data for partial G, that is taken to mean we can't have expert opinions about what is likely to happen over extended periods in partial G, so we might as well try it and see what happens.

The problem with this is that that there is likely to be a dose response curve of symptoms in response to zero G and partial G - as there is to most other biological stressors.

Scott Kelly, by his own estimation, took nearly 3 months to return to normal abilities after a year in zero G.  Contrast this with most astronauts who spend 6 months in space, who fully recover in much less time than six weeks (half of three months).  I think it is a perfectly reasonable prediction that the recovery from 18 months of zero G would be much worse again than the recovery from 12 months.

In which case, it may be that partial G is better for us than zero G, but that is not the same as saying there is a "safe level" of partial G.  More likely it's just that the derivative of the increase in symptoms is lower with partial G, but it's still an "exponential" (actually sigmoid) increase in symptoms.

Which brings us back to the original idea that it is probably an unacceptable risk to send people on 2+ year Mars missions without having done some partial G research first (although I wouldn't exclude missions that go and return during the same synodic).  We just have to get more clever with designing a research platform that doesn't cost an arm and a leg. 

All:  Gary Hudson over at the Space Studies Institute (SSI) has been beating the drum for the need of artificial-gee for human spaceflight for years now and I totally agree with Gary that before we establish long term colonies on the Earth's Moon and Mars, we had first find out if humans can breed in and live long-term under 1/6 and 1/3 gee gravity fields.  A good summary of Hudson's approach to finding the answer to these questions is at the below December 2015 YouTube video URL.  In this video Gary lays out a moderately low cost approach to finding the answers to these biological compatibility questions.

https://www.youtube.com/watch?time_continue=10&v=xO1Pvtv_A4k

Best, Paul M.

Relinking this video because the top way to reduce the cost of building an AG research station is to minimise the number of launches, and this is one way of doing that.

Pedantry side note: Can we please stop talking about Mars gravity as "1/3" G?   It's 38.9% of 1G, and it's only become 1/6 and 1/3 G because Lunar gravity is almost exactly 1/6th of G.

I agree with all your points. Yes, we need research and an orbital spin gravity station is the way to go.

However, Congress isn't interested in giving NASA money to build one and Elon Musk doesn't think it's necessary. The reality of the situation is that SpaceX is going to send a crew to Mars within a decade, assuming they can get their spacecraft to work. We'll get data at Mars gravity levels, just hopefully not at the expense of explorers' lives.

Sure it's dangerous, but so was Apollo, Arctic and Antarctic exploration, climbing Mount Everest, etc. Seriously, people die climbing Everest just trying to prove that they can do it. It's foolhardy, but people still do it.

Best way to get an AG research station built is to convince Elon Musk that SpaceX needs to do the research before going to Mars.

[mikelepage]

<snip> Congress isn't interested in giving NASA money to build one and Elon Musk doesn't think it's necessary. The reality of the situation is that SpaceX is going to send a crew to Mars within a decade, assuming they can get their spacecraft to work. We'll get data at Mars gravity levels, just hopefully not at the expense of explorers' lives.

Sure it's dangerous, but so was Apollo, Arctic and Antarctic exploration, climbing Mount Everest, etc. Seriously, people die climbing Everest just trying to prove that they can do it. It's foolhardy, but people still do it.

Best way to get an AG research station built is to convince Elon Musk that SpaceX needs to do the research before going to Mars.

No particular objection to your summary of the state of affairs, but it does kinda sound like this:
"Maybe it's foolhardy, but we're going to do it anyway..."

I mean, surely there's a better way... 

At Exodus, we're creating a small (washing-machine sized), deployable, "space-origami" structure that can fold up within a long narrow rocket payload bay, and fold out to a segmented, rigid toroid array.  Single launch, no in-space assembly.  I think we've also got some pretty neat mechanisms to control spin orientation and spin rate.

Most importantly, we're looking at all the applications (terrestrial and space-based) where we can start making money from these designs before we even try to scale the concept up to space station size to address the biomedical questions. 

[LMT]

Richie-5

Simplified Richie-class ITS Configuration

The initial "Richie-class" options could support concurrent AG tests - for multiple concurrent mission profiles - in low g, Mars g and Earth g.  Each mission crew would switch between AG environments at each simulated mission AG transition: e.g. transition from in-transit low g to Mars surface g, or from Mars surface g to Mars surface centrifuge Earth g.  All system hardware could be returned to Earth for repair or modification between each experimental run, and then repurposed for deep-space missions at the end of AG testing.

To get greater value out of 5 ITS craft, you could tweak that Richie-class config to get 5 different, concurrent AG environments.  This would enable concurrent AG testing of missions to all bodies between Earth and Mars.

The 5 AG environments:

1.  Earth g
2.  Mars g
3.  Lunar g
4.  Deimos g
5.  low g

5 ITS craft for 5 AG environments:  "Richie-5", one might say.

Mod:



Lunar g:

The left-side cargo ITS is now replaced with a crewed ITS. 

In this craft 2.5 rpm places the lowermost crew quarters at .16 g.

The system's crewed facility volume is now increased by 33%, and water shielding is increased by 25%.

Deimos g:

In the free-flying ITS craft, move shielding water and cargo right, to the top of the craft, to balance a partial propellant load.  This shifts CoM to the ceiling of the lowermost crew quarters.

Rotate at .2 rpm.  The lowermost 2 floors of crew quarters remain in low g.  The ceiling of the common area immediately above crew quarters is placed at 3E-4 g, or Deimos g.

(.27 rpm for Phobos g, if that's useful)

Applications:

Deimos g is not obviously interesting, medically, but there are other uses.  For example that common area could be sealed, giving a toroidal workspace.  Within that workspace you might configure a vacuum chamber with dust and ice:  a Deimos Environmental Test Facility (DETF).  DETF could test hw for, say, digging through Deimos' dry surface regolith and accessing supposed ice-rich material below, for ISRU. 

DETF could be a first experimental step down the notional Omaha Trail.