If an astronaut gets unconscious or ill I suppose the colleague will help her to the airlock. But are there any other measures that could be taken already outdoors? Do they have duct tape to seal a leak in the suit? Can any kind of first aid be provided?
1$\begingroup$ A suit for an EVA is made of many layers for thermal isolation and protection against micro meteroites. Thus the air tight layer holding the pressure can't be the top layer. How would you place duct tape to seal a leak in that special layer? Removing all upper layers with your swiss army knive? Special emergency gloves to be worn over a leaky glove may be possible. But there should be an additional flange at the suit to mount this glove and seal it. $\endgroup$– UweNov 4, 2017 at 10:03
$\begingroup$ A prototype of a rescue ball was build but never flown. A much larger version of such an enclosure to fit a suited astronaut may be possible but heavy and bulky. $\endgroup$– UweNov 4, 2017 at 11:10
None, really. If you examine the EVA Cuff Checklist (the one that is actually taken outside, shown here on Suni Williams' suit - note customized cover) you will see that all emergencies end in either TERMINATE EVA or ABORT EVA (ABORT EVA being faster) if working the procedure doesn't fix the problem. In other words, get back inside where you can actually do something about the problem.
Here's the Cuff Checklist table of contents.
Here's a sample of one of the procedures.
If you get the Suit Pressure Emergency alarm:
Check the hardware gauge to confirm the reading (a redundant sensor to the one that sets off the alarm). If it shows low, check that your valves are closed and the O2 Actuator is in the proper position. Then abort the EVA. (The check mark means check something and fix it if it's wrong. If you find a valve open and closing it works, you're done.) If the hardware gauge shows the pressure is OK, ignore the alarm. But keep checking that gauge!
You can read the whole thing here.
$\begingroup$ Would it be possible for a fellow EVA-astronaut to administer an injection of adrenaline and other stuff that might get a knocked out astronaut conscious for a while again by biologically provoked super stress? Not anything at all but to check the pressure and bring the guy home into the airlock? Imagine that a kilometer from the habitat on Mars. $\endgroup$ Nov 6, 2017 at 18:58
1$\begingroup$ I imagine it could be made possible in some future program. But in today's ISS program, adrenaline is not taken outside, and I am not sure the suit is self-sealing if a needle is jabbed through it. Your question asks what options do they have which to me means, today. A lot could be done, hypothetically, but it's not in effect today. $\endgroup$ Nov 6, 2017 at 19:16
To answer the medical aspects of this question, all Apollo spacesuits had a hypodermic injection port in the right thigh. It was protected by a flap on the outer ITMG layer (p. 14):
Access flaps constructed of a thermal-resistant cross section of materials are held closed by a system of snap fasteners and fire-resistant Velcro tape. These access flaps cover the entrance closure and the UCTA connector and biomedical injection area.
and had a self-sealing patch through the pressure garment assembly (p. 8):
A biomedical injection patch is built into the right thigh portion of the TLSA to permit a crewman to self-administer a hypodermic injection without jeopardizing the gas retention quality of the PGA.
According to Apollo by the Numbers, lidocaine, atropine, demerol, and marezine were available as injectables. Fortunately, they were never used.