[nnhtzgf]

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.

[exDM69]

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?

[nnhtzgf]

As I have said twice now, a crisis can involve abnormal conditions where the usual means aren't available.

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.

[exDM69]

I understand what you mean by crisis.

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.

[bostonpete]

> 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.

[exDM69]

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.

[sandworm]

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.

[lambdadmitry]

AFAIK it's bolted to the station, isn't it? I'm not sure if it's possible to detach it swiftly enough to be useful in an emergency.

Please correct me if I'm wrong.

[exDM69]

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.

[lambdadmitry]

Thank you.

[jccooper]

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.