Not following NASA and the ISS and well as I used to, I know there were plans to build a 'lifeboat' for the crew. Is that a thing now? If something catastrophic happens, what does the crew do?
There's usually two three-person crews on the station at any given time, so two capsules are kept docked and ready to serve as lifeboats.
Since the Soyuz is the sole means of transportation to and from the station, they simply put the capsules into a rotation. When a new crew arrives, they leave their capsule docked and the departing crew rides the oldest capsule back to Earth.
The docked capsules are rated for about six months, due to chemicals aboard that can degrade or escape. So if a replace vehicle doesnt arrive in time, then the astronauts may be forced to return. I recall a complete evacuation of the ISS almost happened after the Columbia accident because there werent enough Soyuz in the pipeline on Earth. The 20-some modules of the ISS are finicky enough that you dont want to leave the ISS empty for too long or it may catastrophically fail.
A lesser concern is that seats have mould inserts specific to the shape of each cosmonaut. I am not sure how they handle swaps. Maybe store the moulds on the ISS.
The seat liners can be installed in Soyuz on-orbit. When the Shuttle was delivering someone who would return on a Soyuz, they'd bring the liner up as cargo on the Shuttle and swap it in. I imagine they routinely do the same for crew who arrive and depart on different Sayuz (which happens fairly regularly.)
If there are six onboard two Soyuz will be docked. Always. There will never not be lifeboat for everyone, nor was there ever not one for everyone. Currently two are docked and those are the two lifeboats.
Those aren’t only lifeboats, though. They are also just the normal crew return vehicles. Here is how crew rotation currently works: Three depart in the oldest Soyuz docked to the station, leaving the station with a crew of three and only one remaining Soyuz. A couple days later a new Soyuz arrives at the station, meaning there’s now a crew of six and two Soyuz docked to the station. Then everyone stays up there for a couple months longer before the now veteran crew departs on the oldest Soyuz and everything repeats.
One advantage of doing it this way is that you are constantly renewing the lifeboats, so a Soyuz doesn’t have to survive years in space, only six or so months before it is replaced. Basically, it has to work for its main purpose (returning the crew to Earth as planned) anyway, insuring that it also works as a lifeboat. (Though I would assume that many changes were made to make the Soyuz work as a lifeboat. I would imagine that rapidly departing from the station, potentially with injured crew, is quite a different task compared to a planned departure.)
This makes me wonder, I assume they have procedures to dock a deserted ISS, right? What would happen in case of an emergency where both teams (3+3) have to return back to Earth, leaving ISS without a crew? Will they be able to "get back in"?
Continuous habitation of a space station is a bit historically unusual. Skylab had three visiting manned missions, none of which overlapped. Early Russian stations operated similarly. Mir was operated more like ISS, but left unoccupied several times. (See http://en.wikipedia.org/wiki/Soyuz_TM-30 for a commercial mission to revive and try to restore the previously-abandoned MIR.)
And the ISS (or early parts thereof) went about two years before its first long-term crew.
So, yes, you can get back into the ISS if it's empty. That capability has been designed into both halves of the space station from the beginning.
Soyuz can dock to deserted stations, or at least could in the past. They had to do it all the time with the Salyut stations, and I suspect it is how the first docking with the ISS went down as well.
Technically there is berthing and there is docking. Berthing requires that both sides cooperate, but docking doesn't necessarily require this. However while docking both sides are very nearly always under control (with the deserted side under robotic control).
Non-cooperative docking has only been done exactly once in the history of human spaceflight on the Soyuz T-13 mission to the Salyut 7 space station [0]. In addition, Wikipedia mentions a few unmanned tests.
In practice, all spacecraft docking and berthing operations are fully automated and no human intervention is required apart from emergency conditions (which have never occured). The last intentional attempt (1997) at manual docking ended up in a bad collision between the Mir space station and a Progress spacecraft [1]. The last Mir mission (Soyuz TM-30) did the last few meters under manual control. ISS crews are trained for manual docking but I don't think has ever been necessary.
In the hypothetical situation that the ISS would be left unmanned, it's extremely unlikely that they would decide to (or have time to) power down the attitude control systems (control moment gyroscopes and thrusters). So even if the station ended up unmanned, it's not likely that it would be non-cooperative (ie. out of control). If all the attitude control systems would disabled because of damage (e.g. fire), the station would probably not be salvageable.
So it's possible but very unlikely to have a scenario where a manned mission would need to manually dock an out of control space station. But it has happened once before, so it's not impossible either.
Well, the ISS was actually built as a constant iterative process, it wasn't just sent on space as is and then assumed operative. Also I'd assume the first module that was sent to space might have contained humans already right on departure from the Earth.
But yeah, obviously they have procedures to retrieve and re-enter an empty ISS, I was mostly curious how or if there's any material around.
Zarya (the first module, launched in 1998) was pressurized and could support a crew short-term-- the crew of STS-88 (which launched Unity, the second module added to the ISS) entered the station and began unstowing gear and stuff. The ISS couldn't support its permanent crew until Zvezda (the station's service module) launched in 2000, though-- Zvezda contains the station's primary life support equipment and contained crew facilities like toilets and bunks.
My guess of a likely reason to completely evac the station is one astronaut gets hurt, two healthy astronauts land with the sick one, then in a stroke of incredibly bad luck another astronaut gets hurt. For hurt, substitute in appendicitis, broken arm, heart attack, severe burn, poisoning from some kind of leak (ammonia?). If you're looking for a hard sci fi plot line, maybe major system malfunction hurts one astronaut, then after the medivac, while making duct tape repairs, another gets hurt, then the space pirates arrive and take charge of a derelict abandoned vessel, or whatever.
I would guess that docking with a completely dead powered down archeological relic of a station would be much more exciting than docking with a powered up and running station that merely happens to not have any humans onboard.
Station without power would start to tumble. Makes docking much harder. This actually happened with Salyut 7: the station died on orbit, no electrical or anything. The pilot of the rescue Soyuz matched its spin to dock manually. Effected emergency repairs while wearing fur-lined winter clothing.
It must not have been tumbling too badly. Seems like once you have significant motion in more than one axis it'd be pretty hard to match up. At that point, you probably have to grab and despin, or something. Or dock really really fast and hope your docking mechanism holds up to the stress.
Trying to fix/salvage it? I'm sure the russians reactivated a "dead" station at least once, sending a better prepared crew to repair quite a while after it was abandoned.
No, it isn't. SpaceX's human-rated Dragons haven't flown yet (and probably aren't finished, nor are they human-rated by NASA yet). The cargo version currently docked has no seats and you definitely can't just hang onto the walls and hope it works.
Of course it is, rating has nothing to do with reality. Dragon has brought supplies safely back to earth every time so far, and the g-forces were on the same level( edit:actually less ) as soyuz. And Dragon is of course pressurized in case it isn't obvious.
As I have pointed out, in a crisis, where there are no other options, it is capable of returning humans. This would involve makeshift seats/beds and landing in the ocean.
There's two Soyuz spacecraft in case things go bad.
If you are aware of a plan to use a Dragon as a lifeboat, please bring out some sources for that.
That's a pretty far fetched possibility and surviving re-entry in an unmanned capsule is unlikely. There aren't any life support capabilities (ie. oxygen for breathing) and surviving the 5-10 G accelerations of re-entry would be rather unlikely without being strapped to a seat.
Can the Dragon spacecraft even undock from the space station and robotic arm without a human operator on the Canadarm controls?
Astronauts will enter Dragon to remove cargo.
Dragon’s cabin is habitable, with air circulation, lighting, fire detection and suppression, air temperature control,
pressure and humidity monitoring.
Transporting Crew
While it initially is transporting cargo, Dragon was designed from the beginning to transport crew and is currently
undergoing modifications to make this possible. Crew configuration will include life support systems, a crew escape
system, and onboard controls that allow the crew to take control from the flight computer when needed. This focus on
commonality between cargo and crew configurations minimizes the design effort and simplifies the human-rating
process, allowing systems critical to Dragon crew safety and ISS safety to be fully tested on unmanned flights.
And the second pdf:
Crew Capability
•Both Dragon & Falcon 9 were designed from
inception to readily accommodate crew
•Immediate focus is on cargo for COTS
& CRS commitments, BUT…
•In every design decision, the ability to attain
human rating rapidly & at low additional cost is
paramount
Note: Many human-rating requirements are
mandated on the cargo vehicle because it must be
safe for ISS crew
Space Exploration Technologies Corp
June 16, 2009
This is why SpaceX was founded
21
Dragon Already Designed to
Accommodate ISS Crew
•For COTS Capabilities A-C, astronauts will enter (and temporarily
inhabit) the Dragon spacecraft for loading and unloading of cargo to
and from the International Space Station
•Therefore, Dragon already meets the manned requirements to allow
this activity, as called out in SSP 50808
•Air sampling and circulation
•ISS crew sample Dragon’s air supply through the Air Revitalization
System (ARS) port before entering the spacecraft, breathing in the
air as provided by the Dragon Environmental Control System.
• Air circulation is provided to ensure safe breathability throughout the
spacecraft
•Temperature and humidity requirements
•Touch temperature limits: between 39 F and 113 F
•Human Factors
•Protection from shock
•Restrictions on sharp corners, sharp edges, exposed screw threads, burrs, and pinch points.
• All fonts, colors, and labels are consistent with SSP 50005.
Dragon is capable of docking and undocking, but for reasons, it is rather berthed via the Canadaarm.
But the question is: is there a planned procedure / contingency plan involving the Dragon as a lifeboat? If not, then it's not going to be used. They have rehearsed procedures for these situations. Including the worst of crises.
The 5 year old link you provided mentions the possibility of modifying the Dragon capsule to provide life boat capabilities. That's not what is up there today. The other one talks about "air circulation" systems, but that's not the same as life support.
> But the question is: is there a planned procedure / contingency plan involving the Dragon as a lifeboat?
Wouldn't it be safe to assume there is such a backup plan? You've got a vehicle that should be able to return humans to earth. If an emergency arose with other vehicle(s) damaged, why wouldn't the Dragon be in the mix? I would assume that in a worst case scenario, all sorts of unusual measures could be taken.
Well no and and yes. The Dragon that is currently attached to the space station is unable to return humans to Earth. As far as I know, it is unable to undock from the space station without human assistance, it doesn't have any kind of seats in it and it's really not capable of transporting humans to or from the orbit. So practically it would mean that someone is left behind, sacrificing their own life to give someone else a marginal chance of survival. This will not happen unless it is known ahead of time that the Soyuz capsules are fatally damaged.
In contrast, the option of using the Lunar Module as a life boat in the Apollo 13 flight was planned and rehearsed ahead of time. Not all the details were worked out because it was thought that the crew would be dead before this would turn into reality (and the whole Apollo program was a bit rushed).
But yes, they must have thought long and hard about the option of using the Dragon. The whole Dragon program is built upon the idea of possibly using it as a life boat in the future but that is not the role of the Dragon up there at the moment. But the lessons learned have been translated into the next-gen human rated Dragon program.
But we don't really have to think about that. The last I heard, the CAPCOM and the crew were discussing about feeding the fruit flies onboard the ISS so the scientific objectives do not suffer more than they have to.
These are references to Dragon the program, the design, not to individual dragon capsules. Given the rate of development in space programs, no two Soyuz are identical, I imagine the answer as to whether a particular dragon would/could carry people back to earth changes with every mission.
For detachment, nearly every large connection in space has explosive bolts for cutting things loose. The docking ports have emergency modes.
Correct. The links in GP describe the option of adding a "quick detach" mechanism, but that was a hypothetical development direction of the Dragon program, not something that currently flies.
Dragon is "berthed" to the ISS, unlike Soyuz which is "docked".
Berthing is what they do to ISS modules. It's basically bolted on--which requires a fair bit of work from the crew on the station side, both mechanically and in getting the spacecraft in place (which they do by robotic arm capture). They do this for the cargo stuff because the berthing mechanism is wider, lighter, and cheaper.
Docking is what you do for a manned spacecraft. They have fancy mechanisms to attach and detach quickly and mostly-automatically. It's complex and the opening is enough to get people through, but it's fast and easy. A docked spacecraft can leave on its own; a berthed one would require crew still on to help.
While cargo Dragon could take a person down to Earth, and they'd probably survive (probably nestled among bags of trash), it's not going to do so in a hurry, and since you have a seat on a Soyuz already, and it's designed for it, you might as well use that. Especially if you're in a hurry. I think the only time cargo Dragon would be involved would be something catastrophic happening to one of the Soyuz--but not to anything else.
