BFS - the Human Factors - Updates and Discussion

[DreamyPickle]

People can survive several months in zero-G just fine, this was proven on Mir and ISS several hundred times. At most the crew will be a little out-of-shape when they land but being the first on the surface of a new planet should provide a sufficient adrenaline shot. And they can rest a while until the crane is checked out.

It would be great to have medical data from living for long durations in low gravity but the risk of something going wrong seems very low. SpaceX doesn't have a good reason to invest resources in this.

[corneliussulla]

It seem likely to me that the first 2 crewed ships will probably have crews of 10-12 in size. Probably 1 specialist of each type on each crew. For instance 1 doctor on each crew etc. They need to have plans to cover loss of crew during flight/EDL and during the mission.

 So with that size crew I would think the life support systems used on the ISS would be a good starting point. No need to build the first few ships with life support systems for 120 people. Those crew sizes are probably in the 2030 and beyond time period and as the ships are coming directly back to earth they can be retro fitted.

[console65]

It seem likely to me that the first 2 crewed ships will probably have crews of 10-12 in size. Probably 1 specialist of each type on each crew. For instance 1 doctor on each crew etc. They need to have plans to cover loss of crew during flight/EDL and during the mission.

I would think it would be double that number.  There should be skill redundancy for such a long duration mission far from any sort of help.  Yes, technically there would be two doctors, and pairs of other such specialists, on the mission but it would be one specialist on each ship and if, God forbid, something were to happen to one of the ships...

[speedevil]

Apart from the load paths, the current design doesn't provide for constant rotation. The solar panels couldn't track the sun, for example.

The solar panels could easily track the sun if you orient them parallel to the ships wings, and have the rotation around an axis in parallel with a line pointing 'up' from the wings towards the sun.

With a small counterweight, it both could track the sun, and the load paths do not change.
Assuming for the moment there is a nose-hook which can take 100 tons or so for lifting, placing a counterweight so it can rotate will allow you to have ~1m/s^2 acceleration, or ~0.1g. 0.1G.
As rotational acceleration = velocity squared divided by radius. A=V^2/r -> 1=V^2/r -> r=V^2 -

So, at 100m/s, radius is 10km, with a ten minute period - probably a bit excessive. 20m/s gives 400m radius, 120 second.
With a 4.4km tether, that'd be around a ten ton counterweight.

It would be moderately expensive unless you have some use for the weight on Mars.

(I am not of course saying that this is what they should do, and it does add a complication)

[biosehnsucht]

It seem likely to me that the first 2 crewed ships will probably have crews of 10-12 in size. Probably 1 specialist of each type on each crew. For instance 1 doctor on each crew etc. They need to have plans to cover loss of crew during flight/EDL and during the mission.

I would think it would be double that number.  There should be skill redundancy for such a long duration mission far from any sort of help.  Yes, technically there would be two doctors, and pairs of other such specialists, on the mission but it would be one specialist on each ship and if, God forbid, something were to happen to one of the ships...

I imagine you'd just have a bunch of people who are multi-specialists. At least two people who are "full medical doctors" on each ship, capable of dealing with ANYTHING that could happen that could be dealt with (i.e., no need for brain surgeons or transplant surgeons, but there's still a wide array of things you might need to deal with), and most of the rest would have basic medical training like you'd see for ordinary military personnel (bandages, splints, etc).

Similarly, you'd have overlapping "mission specialists" such as two  or more people trained in all the intricacies of the ISRU equipment, others in the power systems, ECLSS, etc, such that everyone knows at least two things really well and knows enough about the rest to follow orders from those that do (or use a manual). There may not be time to wait for instructions from Houston, after all. Just make sure that at least two people know enough about each thing that either might need to be fixed (and could be - if it can't possibly be fixed outside of Earth, no need to worry about it) or put together / set up on Mars.

This isn't just about redundancy of knowledge for survival either, you might really need two or more people of a given specialty to fix or set up certain things.

[CuddlyRocket]

15 years of ISS operations have given us a huge knowledge base about what to do and what NOT to do.

Isn't the ISS ECLSS system known for having somewhat frequent breakdowns? Such issues would be harder to deal with on the BFS because it has to operate at a significant light-lag from ground-based experts and emergencies are potentially catastrophic.

The primary goal should be reliability, even at the expense of efficiency. After it lands the plan is to collect very large amounts of water anyway so very long term closed-loop operations are less interesting than for a space-station.

I think a lot of the problems and expense of the ISS ECLSS are due to various restrictions on resources that it has had to be designed to cope with - namely: volume, mass, power and amount of human intervention. With BFR as designed, all of those (except possibly the power) will be a lot less restrictive. Most notably the amount of human intervention available. The ISS is designed to run as autonomously as possible as the crew has lots of other things to do. With many BFR missions, the problem will be finding something for them to do!

[Johnnyhinbos]

Astronaut Chris Hadfield’s balanced reaction to Elon’s 2017 BFR presentation, which also touches on human factors issues...

[Johnnyhinbos]

There's an interesting bit of conversation that's germane to the human factors component over on the "Re: IAC 2017 -- BFR v0.2 - DISCUSSION THREAD 3 (Post Speech)" thread. I'm hoping to get the conversation moved over to this thread in order to keep the conversation going...

https://forum.nasaspaceflight.com/index.php?topic=43920.msg1734192#msg1734192