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?
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.
edit: There's also the now cancelled http://en.wikipedia.org/wiki/Crew_Return_Vehicle, which is probably what you were thinking of.
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.)
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.
But reading http://er.jsc.nasa.gov/seh/docking_with_ISS.pdf, at least the Space shuttle could dock with MIR all on its own.
Also, reading http://en.m.wikipedia.org/wiki/Docking_and_berthing_of_space..., there are almost more standards for docking mechanisms than different types of spacecraft.
http://en.wikipedia.org/wiki/Assembly_of_the_International_S...
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.
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.
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).
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.
[0] http://en.wikipedia.org/wiki/Docking_and_berthing_of_spacecr... [1] http://en.wikipedia.org/wiki/Progress_M-34#Collision
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.
Last time it happened was Nov 2013, and apparently previously in 2009:
http://www.space.com/23542-space-crew-olympic-torch-landing-...
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.
They've got a Soyuz for that.
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.
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?
Your third paragraph is not correct at all. Dragon has life support and reentry acceleration of 3.5g.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2011001...
http://www.nasa.gov/pdf/361838main_11%20-%20SpaceX%20Augusti...
Quoting from the first pdf:
Environmental Control System
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.
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.
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.
For detachment, nearly every large connection in space has explosive bolts for cutting things loose. The docking ports have emergency modes.
Please correct me if I'm wrong.
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.
In an extreme emergency, a crew could put on emergency breathing equipment, and use makeshift seating, then ride the capsule home.
One of the major reasons the Dragon v1 can't launch with human crew inside is that it has no launch abort system.
For example: http://www.space.com/15031-space-junk-station-astronaut-thre...