NASA SLS/Orion/Payloads

[DAL59]

8 hours ago, Green Baron said:

People coming from LEO after 6 months are in a bad shape, they have to be carried away, bones and muscles atrophied, arteries stiffened, eyesight lowered and with the immune system damaged.

That is true, but that is due to zero gravity which is the same in lunar orbit as in LEO.  

8 hours ago, Green Baron said:

So there is still a long way to go research wise before somebody gets a ticket to Mars, if its not a one- or even one-half-way ticket.

But its the same risk as being in LEO for 6 months.  We know they can survive 6 months in zero g, so they can survive a trip to Mars.  

[Nightside]

@_Augustus_, I've got a FAQ for your OP. 

I forgot what DST stands for is it the same things as DSG?

For anyone, are any of these landers people are talking about even remotely on NASA's todo list,  have they actually asked for proposals?

[_Augustus_]

1 minute ago, Nightside said:

@_Augustus_, I've got a FAQ for your OP. 

I forgot what DST stands for is it the same things as DSG?

Let me put the answer in the OP.

[DAL59]

1 minute ago, Nightside said:

I forgot what DST stands

Deep Space Transport

[Nightside]

12 minutes ago, DAL59 said:

Deep Space Transport

Yeah I probably could have guessed it if I thought about it a bit. I thought it stood for Deep Space TLA.

[Green Baron]

23 minutes ago, DAL59 said:

That is true, but that is due to zero gravity which is the same in lunar orbit as in LEO.  

Several other risks are added in lunar orbit, like radiation/high energy particles, harder supply chain, more sophisticated procedures ...

Quote

But its the same risk as being in LEO for 6 months.  We know they can survive 6 months in zero g, so they can survive a trip to Mars.  

Nope, the risk is much higher. And the journey doesn't take 6 months, it takes 2-3 years. Just read the link i posted ! A new risk compared to lunar orbit for example is the nutrition, people won't stay healthy from dry food only for three years. And that's one point from a list of several pages.

The lunar orbit station, if they do it, is a good demonstrator and test contraption for these things with a chance of getting people home in a matter of days should the need arise.

Edited December 3, 2017 by Green Baron

[DAL59]

33 minutes ago, Green Baron said:

And the journey doesn't take 6 months, it takes 2-3 years.

Most of it on Mars surface.  Also, the ITS reduces transit times.  

33 minutes ago, Green Baron said:

like radiation/high energy particles,

Again, cosmonauts have been exposed to equal radiation.  

34 minutes ago, Green Baron said:

people won't stay healthy from dry food only for three years.

You could test nutrition on Earth for far less cost.  The ITS would also enable higher masses of food.  

35 minutes ago, Green Baron said:

harder supply chain,

then just do ISS resupplies less often.  

[Green Baron]

13 minutes ago, DAL59 said:

Most of it on Mars surface.  Also, the ITS reduces transit times.  

Only a few days. No ITS because no ITS because no ITS.

Quote

Again, cosmonauts have been exposed to equal radiation.  

No.

You didn't even take a look at what i linked, is that true :-) ? So here's more food for the brain. I am glad that people at Nasa are aware.

https://srag.jsc.nasa.gov/Publications/TM104782/techmemo.htm

https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays

and

https://www.nature.com/articles/srep29901#t1

The authors if the last one admit that the sample is too small. But these are the only ones.

Quote

You could test nutrition on Earth for far less cost.  The ITS would also enable higher masses of food.  

We do. It costs 100s of billions in the developed countries because people get sick.

Quote

then just do ISS resupplies less often.  

Now THAT one is shooting soldiers ;-)

Edited December 3, 2017 by Green Baron

[DAL59]

Just now, Green Baron said:

Now THAT one is shooting soldiers ;-)

No, because they can get back to Earth in a matter of hours, and they'd know they would run out of food or spares in advance.

1 minute ago, Green Baron said:

Only a few days.

A conjunction class mission spends 500 days on the surface.  In Mars orbit, 50% of radiation is blocked because half the sky is blocked by Mars.  

9 minutes ago, Green Baron said:

No ITS because no ITS because no ITS.

They've already reassigned many employees to work on that.  IT Seems very practical.  

[Green Baron]

43 minutes ago, DAL59 said:

No, because they can get back to Earth in a matter of hours, and they'd know they would run out of food or spares in advance.

"Hey guys ! We've halved your rations ! If you want to quit, any time, take the dinghy. We'll pick you up when we have the time !"

Quote

A conjunction class mission spends 500 days on the surface.  In Mars orbit, 50% of radiation is blocked because half the sky is blocked by Mars.  

A what ?

And there is a ground crew on Mars that helps the poor guys and gals out of the can, gives them a glass of champagne (one for all because budget), there is medical supply and Bones waits just around corner ("He's dead, Jim !").

 

I am sorry and must apologize for being sarcastic, just this morning i criticized a colleague for playing his jokes on me. Sorry @kerbiloid !

 

Edit: the grafic you linked, @DAL59, is most likely a fraud, the sources i ckecked tell a different story. Example: https://www.nasa.gov/home/hqnews/2013/may/HQ_13-165_MSL_Radiation_Findings.html

tldr: Survivable. I mean, exactly that, survivable. Just not by everybody.

 

Edit: https://www.aaas.org/news/science-mars-mission-reveals-radiation-risk-future-astronauts

Edited December 3, 2017 by Green Baron

[tater]

21 minutes ago, DAL59 said:

They've already reassigned many employees to work on that.  IT Seems very practical.  

They've assigned no employees to work on ITS, ITS is not a thing any more. Perhaps you refer to BFS or BFR?

An n of 4 is not useful for epidemiology, wake me when it's 1000 or something.

[DAL59]

4 hours ago, tater said:

An n of 4 is not useful for epidemiology, wake me when it's 1000 or something.

A DSG won't expose 1000 people to radiation.  

4 hours ago, tater said:

ITS, ITS is not a thing any more. Perhaps you refer to BFS or BFR?

Its the same ship.  Yes, the new version is smaller, but the naming is a bit confusing.  

[tater]

It’s not the same at all, it’s quite different.

I’m not defending DSG, I’m merely saying 4 cosmonauts is not terribly useful.

[PB666]

8 hours ago, Green Baron said:

 

Edit: the grafic you linked, @DAL59, is most likely a fraud, the sources i ckecked tell a different story. Example: https://www.nasa.gov/home/hqnews/2013/may/HQ_13-165_MSL_Radiation_Findings.html

Edit: https://www.aaas.org/news/science-mars-mission-reveals-radiation-risk-future-astronauts

I thought that was rather obvious. Dal appears to be frothing at the mouth over this Mars stuff. The MSL CR study was published years ago, no surprises there except that during relatively low sun-spot activity there was GCR obviously higher then expected. Anyone who is thinking of a transfer ship under 50t needs to walk away from the argument now. At least once you get on Mars the CRB is half what it is in interplanetary space. The habitat lander could be buried in Martian substrate for added protection, you could knock the level of exposure down to about a fifth of IPT exposure.

I have been presenting examples of interplanetary ships that are in the 200t region, and propulsion systems that can make the transfer,  there is a reason for that. IMO we have to get the hydrogen storage and gas recycling done not just to provide fuel for mars landing and, but also to provide a GCR trap. Currently my largest ship gets 2kt into orbit. CGR is not a death nail in interplanetary manned space flight. It can be dealt with (for example placing hydrogen tanks around the crewed areas, more work could be done on design and placement of magnetic fields around ships, etc. The ISS is not a test bed for GR exposure in so much as its a test bed for exposure for microgravity, whose effects may plateau over time. To get to Mars will require more investigations outside of Earths magnetic field. Things like GR sensors implanted under the skin. More sensors added inside of space craft. Attitude based avoidance of GR (including detectors and reaction systems), etc.

ITS is a concept, from what I have seen its food for the media and directive for SpaceX to progress, the design is pretty, practicality however dictates design in space.

A couple of things I need to correct/opine in this thread.

1. Green leafies can be stored indefinitely at -50'C or below. I anticipate that one thing SpaceX will be able to do is dispatch cargo ships capable of reaching LMO. When a definitive Mars atmosphere aerobraking strategy is worked out such deliveries could be routine. The technology is progressing rapidly.
2. Everyone shows a Mars lander and ascent vehicle (also Lunar lander and ascent). The lander and ascent vehicles may be a separate enterprise. The lander habitats they separately for people to stay in. Just assume that its a two ship enterprise.
3. From my point of view, if the CRB is the biggest problem in interplanetary transfer then you will not ditch your ship landing on Mars, that transfer ship will remain in orbit waiting for the lander. One strategy is that the ascent vehicle provide at least some of the dV to get it back in to LEO. You can carry the utilitarian lander as a package on the transfer ship, but my assumption is that it will remain in Mars SOI.
4. If we are talking about suitability of radiation exposure on Mars, then I think we need to consider the fact that some sort of automated preparation needs to be done (i.e. to the habitat lander) before humans arrive. Otherwise you are going to have humans out trying to lower their habitat and carry tons of sand and rock into the habitat area.

 

 

Edited December 4, 2017 by PB666

[Green Baron]

4 hours ago, PB666 said:

 The MSL CR study was published years ago,

True. I actually asked myself why didn't i find it last time we had this discussion ... maybe a slight change in search term spelling ... :-)

 

[DAL59]

7 hours ago, PB666 said:

then I think we need to consider the fact that some sort of automated preparation needs to be done (i.e. to the habitat lander) before humans arrive

Musk is sending 2 ships in advance.  

The ITS has a pretty large payload capacity, so it should be able to carry enough protection.  It also has a storm shelter.

11 hours ago, tater said:

I’m merely saying 4 cosmonauts is not terribly useful.

The DSG will also have 4 astronauts.  

[tater]

1 hour ago, DAL59 said:

Musk is sending 2 ships in advance.  

The ITS has a pretty large payload capacity, so it should be able to carry enough protection.  It also has a storm shelter.

There is no such thing as ITS, no ITS are being sent anywhere, ever. 

BFR/BFS is another story.

1 hour ago, DAL59 said:

The DSG will also have 4 astronauts.  

Yeah, and it's only enough for anecdotal data.

[Green Baron]

But - if the DSG is done one future day - it would be the first data obtained in a controlled way. That could mean a step forward out of the current insecurity. Nasa says that even during a quiet journey in a craft shielded better than the Apollos the crew will take a too high radiation dose. "Anecdotal" data is data as well :-)

But well, assuming the first launch of the SLS takes place at the end of 2019, we won't see a DSG around the moon before the mid or late 2020s ...

Edited December 4, 2017 by Green Baron

[kerbiloid]

_

56 minutes ago, tater said:

Quote

The DSG will also have 4 astronauts.  

Yeah, and it's only enough for anecdotal data.

As lab technicians or as lab animals?

[wumpus]

Er, I get 8.5 months for Hohmann transfer to Mars.  The idea that BFR could cut this down seems impossible (nor crew taking a longer path).  https://www-istp.gsfc.nasa.gov/stargaze/Smars1.htm

That's just for zero-gee, although your "atrophied astronaut" would only have to deal with Mars' .375g gravity, so recovery (to Mars levels) would hopefully be quick.  Expect hospitalization when returning to Earth (8 months of 0g after "normalizing" to .375g won't do well at all at full Earth gravity).  Radiation is another story.  I've seen plenty of work done on "building with lunar concrete" but nothing about Mars (presumably thanks to no return samples, although some meteors appear to be martian).  I'd be curious if you could cover your Mars base with martian rock/dirt (or at least the sleeping quarters) in an effort to reduce radiation.

Note that in zero-g, Apollo astronauts could deal with incredibly cramped quarters.  If astronauts spent a significant amount of time (possibly just sleeping) in small, fixed locations then shielding them would be far easier.  I'd expect that ISS data is key for this type of thing.

Edited December 4, 2017 by wumpus
s/6/8

[Ultimate Steve]

1 hour ago, wumpus said:

Er, I get 8.5 months for Hohmann transfer to Mars.  The idea that BFR could cut this down seems impossible (nor crew taking a longer path). 

If you've got more fuel available to you than what you need for the lowest energy Hohmann, than you can get to Mars faster. Your aerobraking/capture burn will be more intense, but it is doable.

[tater]

1 hour ago, wumpus said:

Er, I get 8.5 months for Hohmann transfer to Mars.  The idea that BFR could cut this down seems impossible (nor crew taking a longer path).  https://www-istp.gsfc.nasa.gov/stargaze/Smars1.htm

That's just for zero-gee, although your "atrophied astronaut" would only have to deal with Mars' .375g gravity, so recovery (to Mars levels) would hopefully be quick.  Expect hospitalization when returning to Earth (8 months of 0g after "normalizing" to .375g won't do well at all at full Earth gravity).  Radiation is another story.  I've seen plenty of work done on "building with lunar concrete" but nothing about Mars (presumably thanks to no return samples, although some meteors appear to be martian).  I'd be curious if you could cover your Mars base with martian rock/dirt (or at least the sleeping quarters) in an effort to reduce radiation.

Note that in zero-g, Apollo astronauts could deal with incredibly cramped quarters.  If astronauts spent a significant amount of time (possibly just sleeping) in small, fixed locations then shielding them would be far easier.  I'd expect that ISS data is key for this type of thing.

There are plenty of transfers that can be done in substantially lower times. Some under 100 days, many at ~120 days.

Mess with the NASA trajectory browser.

[sevenperforce]

If your plan is to orbit Mars before landing, then you have to do a braking burn. The lowest-energy Hohmann transfer has both the smallest exit burn at Earth and the smallest injection burn at Mars. If you want to do a faster transit, you need to add fuel for both a larger exit burn AND a larger injection burn. And since the extra fuel for the injection burn is extra payload for the exit burn, the exit burn must be correspondingly larger. Classic tyranny of the rocket equation. And since all launches to Mars thus far have been single-lifter affairs, the exponential nature of the rocket equation means you'd need to double or triple the size of your launch vehicle to even moderately shorten the transfer time.

The BFR, of course, finds a way around this. If you're aerobraking in to Mars from Earth with a lifting body like the BFR, you get to skip the braking burn. This means any extra fuel you have can go straight to shortening the transfer window, without needing to hold any in reserve for a braking burn. And since it refuels from Earth, it's easy to add more fuel for a faster transfer. You can even do fun things like a high-elliptic transfer, where you place your transfer vehicle on an elliptic Earth orbit first, then refuel, then do the exit burn since you're already basically halfway there.

[DAL59]

4 hours ago, wumpus said:

8.5 months for Hohmann transfer to Mars.  The idea that BFR could cut this down seems impossible

Thats not how transfers work.  8.5 months is the worst possible transfer.  Without too much extra fuel, it could be reduced to 6 months, but past 4 months it grows exponentially. SpaceX has done its math. 

5 hours ago, Green Baron said:

Nasa says that even during a quiet journey in a craft shielded better than the Apollos the crew will take a too high radiation dose

Zubrin says that is completely false.    

[Canopus]

Will Zubrin volunteer for the first Mars flight in Elon‘s Magic BFR?  

Edit: Found this article about the ITS from Zubrin himself with some interesting criticism: http://www.thenewatlantis.com/publications/colonizing-mars

Edited December 4, 2017 by Canopus