Author Topic: Bailout from ISS on a CRS Dragon in case of an emergency.  (Read 33896 times)

Offline manboy

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #40 on: 01/21/2012 05:59 am »
But a more realistic scenario is: 6 people onboard, space station disabled, only one of 2 Soyuz capsules are reachable or working. The Soyuz users unberth the Dragon and then undock themselves.
I think it needs to be clarified why the Soyuzes would be either unreachable or inoperable.  And if inoperable why it would not be easier to slowly rotate the crew down as was considered for STS-135 crew if they had become stranded.

I feel its necessary to clarify because as of right now it seems like it would be incredibly dangerous to try to return the crew in a cargo Dragon.
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline douglas100

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #41 on: 01/21/2012 10:13 am »

I think it needs to be clarified why the Soyuzes would be either unreachable or inoperable.  And if inoperable why it would not be easier to slowly rotate the crew down as was considered for STS-135 crew if they had become stranded.

Exactly. And a replacement Soyuz can be launched unmanned and dock automatically, if necessary.
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Offline cuddihy

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #42 on: 01/21/2012 11:03 pm »
Yes, since they dock at the same location it's unlikely...unless we're talking MMD hit on a soyuz, disabling that Soyuz only.

If it happened during a time when Russia was unable to launch (say post another Russian revolution), I could see the scenario unfolding that way.

Offline A_M_Swallow

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #43 on: 01/21/2012 11:34 pm »
I think it needs to be clarified why the Soyuzes would be either unreachable or inoperable.  And if inoperable why it would not be easier to slowly rotate the crew down as was considered for STS-135 crew if they had become stranded.

I feel its necessary to clarify because as of right now it seems like it would be incredibly dangerous to try to return the crew in a cargo Dragon.

Try a simple reason - the Soyuz crashed whilst docking.  Possible damage to both Soyuz and docking port.

edit: spelling
« Last Edit: 01/21/2012 11:35 pm by A_M_Swallow »

Offline nacnud

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #44 on: 01/21/2012 11:44 pm »
You would also have to make the other Russian ports unavailable and for a Soyuz to be unable to be grappled

Offline manboy

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #45 on: 01/21/2012 11:48 pm »
I think it needs to be clarified why the Soyuzes would be either unreachable or inoperable.  And if inoperable why it would not be easier to slowly rotate the crew down as was considered for STS-135 crew if they had become stranded.

I feel its necessary to clarify because as of right now it seems like it would be incredibly dangerous to try to return the crew in a cargo Dragon.

Try a simple reason - the Soyuz crashed whilst docking.  Possible damage to both Soyuz and docking port.

edit: spelling
At the moment there are four docking ports on ROS, if one is damaged than there are three other that can be used.
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline Jorge

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #46 on: 01/21/2012 11:59 pm »
I think it needs to be clarified why the Soyuzes would be either unreachable or inoperable.  And if inoperable why it would not be easier to slowly rotate the crew down as was considered for STS-135 crew if they had become stranded.

I feel its necessary to clarify because as of right now it seems like it would be incredibly dangerous to try to return the crew in a cargo Dragon.

Try a simple reason - the Soyuz crashed whilst docking.  Possible damage to both Soyuz and docking port.

edit: spelling
At the moment there are four docking ports on ROS, if one is damaged than there are three other that can be used.

Right. The Russians can always undock a Progress to free up a port.
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Offline Robotbeat

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #47 on: 01/22/2012 02:59 am »
Yes, since they dock at the same location it's unlikely...unless we're talking MMD hit on a soyuz, disabling that Soyuz only.

If it happened during a time when Russia was unable to launch (say post another Russian revolution), I could see the scenario unfolding that way.
Wasn't that much of a problem last time there was a revolution. Mir was continually inhabited during the fall of the Soviet Union, and the next launch to Mir after the fall of the Soviet Union (from the independent Kazakhstan) happened before the previous crew departed.

It may well be safer for the crew to be provisioned with unmanned vehicles until a safer option for departing ISS was found. An accelerated commercial crew vehicle or Orion would probably make more sense than an unmodified Dragon Cargo if for some reason Soyuz was just impossible to use. Make them exercise twice as often and give them bisphosphonates to treat osteoporosis (which has already been tested pretty successfully on ISS) while a safer option for Station-egress is found.
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Offline rubtest

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #48 on: 01/23/2012 08:22 am »
What I understood from the answers to this topic is that the usage of Dragon as emergency downhill lift is quite risky, especially the control after leaving the ISS space.
from reading the CBM specs I understood that without power the berthing mechanism
is blocked and can not be reopened manually, because the locking pins.   
I would suggest anyway to  SPACEX and NASA if I may to monitor the environment in the return Dragon capsule with some simulated human load ( heat 60 w per person ? , CO2 exhaust ).something more elaborate then cheese cake.  maybe they have thought about it too.

cheers

 

Offline apace

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #49 on: 01/23/2012 10:23 am »
What I understood from the answers to this topic is that the usage of Dragon as emergency downhill lift is quite risky, especially the control after leaving the ISS space.
from reading the CBM specs I understood that without power the berthing mechanism
is blocked and can not be reopened manually, because the locking pins.   
I would suggest anyway to  SPACEX and NASA if I may to monitor the environment in the return Dragon capsule with some simulated human load ( heat 60 w per person ? , CO2 exhaust ).something more elaborate then cheese cake.  maybe they have thought about it too.

cheers

 

Why? For the cargo missions, the space is needed for the cargo and for the future human craft, there will be a life support system and procedures to rate it for human use. There's simply no nood for a dragon as a life boat now.

Offline rubtest

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #50 on: 01/23/2012 11:06 am »

---------- quote ----------------------------------------------------------
Why? For the cargo missions, the space is needed for the cargo and for the future human craft, there will be a life support system and procedures to rate it for human use. There's simply no nood for a dragon as a life boat now.
---------------------------------------------------------------------------------------
Because it is ( almost) there...
the first Cargo Vessel that  will return safely to earth with a pressurized room
probably also with room temperature inside. Monitoring sensors for temperatue pressure, Vibration  and humidity are probably already build in ( for the cargo of course ) .
such a vessel can really be used first as a return possibility of live experiments from ISS.

heater are also surly on board ( for the pressurized cargo) and can be turned on on
the way back to simulate human presence . CO2 can be produced from some pieces of dry ice ..
« Last Edit: 01/23/2012 11:08 am by rubtest »

Offline douglas100

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #51 on: 01/23/2012 11:17 am »
What's the point of going on with this discussion? The Dragon as currently designed can't be used as a lifeboat. Period.
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Offline rdale

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #52 on: 01/23/2012 12:14 pm »
But if you put a cheesecake in it - maybe it will be?

:)

Offline Jim

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #53 on: 01/23/2012 01:39 pm »

Because it is ( almost) there...
the first Cargo Vessel that  will return safely to earth with a pressurized room
probably also with room temperature inside. Monitoring sensors for temperatue pressure, Vibration  and humidity are probably already build in ( for the cargo of course ) .
such a vessel can really be used first as a return possibility of live experiments from ISS.

heater are also surly on board ( for the pressurized cargo) and can be turned on on
the way back to simulate human presence . CO2 can be produced from some pieces of dry ice ..


Not a good enough reason.  They are already designing a manned version, no need to waste money testing something they don't need to.

And no, there are no heaters, no need for them.
and dry ice is not useable since it would have to be installed days be fore launch.

This is meaningless
« Last Edit: 01/23/2012 01:40 pm by Jim »

Offline cuddihy

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #54 on: 01/23/2012 01:55 pm »
What's the point of going on with this discussion? The Dragon as currently designed can't be used as a lifeboat. Period.

Obviously you haven't read this thread very carefully. A better answer is 'shouldn't be used as a lifeboat...' A lifeboat is not your second option--it is a last option when the Stuff hits the fan.

I'm not sure why you're saying 'can't'. After all, so much depends on the actual details of the use. A 24 hr in-space lifeboat before de-orbit? Ok, I'll buy 'can't' in that case. Just as your standard 2 man emergency lifeboat 'cant' work for survival in arctic waters.

On the other hand, as an alternative to death on a failing station? Odds of survival on Dragon infinitely better than in a Progress, although significantly worse than in a Soyuz.

So? Obviously this is for a 'not enough Soyuz available' scenario, and a 'station incapable of extended sheltering' as well.

That said, there's nothing inherently dangerous about Dragon's design for return. Weak points are as follows:
1.Inability to self-deberth. Ok, clearly requires someone to stay behind and perform de-berth.
2. Lack of ventilation and atmospheric life support.
A. Ok, that restricts lifeboat use based on # astronauts aboard and time to landing (I'm not sure what the minimum time from hatch shut to landing would be. My guess is 5-6 hrs. Anyone know?) 
Or
B. requires addition of temporary atmospheric support such as rebreathers, again restricted by # people and time to landing. Some methods would additionally require Dragon to relieve excessive pressure.
3. Thermal support. Ok, this one needs some data to determine. Can Dragon w/ trunk handle people thermal loads? We don't know yet, but obviously without ventilation this is a question mark even if the capsule itself can handle the loading, can the people handle the heat. Again this will be time dependant.
4. Handling/avionics. Come on. Surely this  can be figured out after a CRS flight or two.
5. Physical loading on the astronauts. Clearly the biggest hurdle. Without built-in couches I think it is an open question if astronauts would survive de-orbit acceleration, parachute deployment, and splashdown. One mitigation method discussed above is emergency use stowable couches that would be kept on ISS unless needed for lifeboat use. Like 2B above, it would probably require minor design mods to Dragon.

So what we have is 5 major issues with using Dragon as a lifeboat, some of which restrict number of people or are time-to-deorbit dependant, and two of which, #2B and #5, require additional design work on Dragon or additional lifeboat supplies to be provided.

All that says 'yes, Dragon can be used as a life boat in an emergency, but it requires some additional work first'.



Offline Jim

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #55 on: 01/23/2012 02:20 pm »

So what we have is 5 major issues with using Dragon as a lifeboat, some of which restrict number of people or are time-to-deorbit dependant, and two of which, #2B and #5, require additional design work on Dragon or additional lifeboat supplies to be provided.

All that says 'yes, Dragon can be used as a life boat in an emergency, but it requires some additional work first'.

No, it doesn't.  You keep over looking the major issue, lack of physical room for the evacuees.   The vehicle is full of hardware, like large cubbyholes to hold logistics items.
« Last Edit: 01/23/2012 02:29 pm by Jim »

Offline kevin-rf

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #56 on: 01/23/2012 02:33 pm »
Don't worry Jim, the cargo dragon will get an astronaut down, no matter how many trips it takes... cue the bandsaw ;)
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Offline rubtest

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #57 on: 01/23/2012 03:24 pm »
Don't worry Jim, the cargo dragon will get an astronaut down, no matter how many trips it takes... cue the bandsaw ;)

exactly , why didn't we think about it before. ! no place ?  make place !
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Offline douglas100

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #58 on: 01/23/2012 04:12 pm »

All that says 'yes, Dragon can be used as a life boat in an emergency, but it requires some additional work first'.

Which doesn't contradict what I said in my post. To use the current dragon to try to escape from the station would be an act of extreme desperation. It wouldn't be like getting into a lifeboat, it would be like jumping out of the upper floor of a burning building.

As for the work needed to turn Dragon into a lifeboat, Jim already answered that. It would be more than "some additional work."
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Offline dcporter

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Re: Bailout from ISS on a CRS Dragon in case of an emergency.
« Reply #59 on: 01/23/2012 04:53 pm »
TO SUMMARIZE

Using a cargo dragon to get people home in an unexpected emergency would take as-much-or-more work and with more as-much-or-more danger than Apollo 13 (including apparently doing insane Michael Bay style blow-torch on-orbit mods to get the racks out and make room for the people) (and would require them to be wrapped in bubble wrap and hold their breath), and in almost every such conceivable emergency there would be legions of better options.

If you're looking for the answer to be "yes that's possible" then you can concoct an action movie scenario. The real world answer is as close to "no way c'mon man" as you can get.

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