Why did the Asgardians need McKay & Jackson's help to activate the Attero device?

Question

In "First Contact" (S5/E10) Drs. McKay & Jackson find one of Janus' secret labs on Atlantis. In the lab, there is a simple-looking box which acts as a homing beacon for a highly advanced race who quickly steals the box as well as absconds with McKay & Jackson. When they return to their icy planet, (it turns out they are cloned Asgardians that migrated to the Pegasus galaxy long ago), they force the doctors to get the "Attero device" working again now they have the missing part.

The Asgardians indicated they needed McKay's ATA gene to get it working. However, they've been living and operating on a Lantean outpost on the icy planet for nearly 10,000 years (another Janus secret lab) as well as they are flying/fighting in Lantean spaceships. They've seemed to have gotten past Lantean gene safeguard long ago. Further, Asgardian knowledge/technology is superior to humans.

Why then, would they need McKay's help getting the Attero device to work again?

Answer 1

This isn't explained on the show, but it's somewhat more sensible than it first appears; there, a couple of contributing factors:

• The Vanir are strapped for resources. At one point Daniel has a long conversation with the Vanir leader, who suggests that his people are in somewhat dire straits (emphasis mine):

  Vanir: The Wraith do not tolerate the presence of advanced technologies other than their own. Before we knew what was happening, we were under attack. We lost our intergalactic ships in the first battle, and we did not have the resources to build more.

  [...]

  Vanir: We had no choice but to abandon our settlements and retreat to a place where the Wraith could not look for us - a planet with a toxic atmosphere.

  [...]

  Vanir: It was tolerable at first. We were able to survive using simple breathing apparatus. But over the eons, the environment has grown so harsh that not even our armored exoskeletons can protect us now.

  [...]

  Vanir: My people are dying.

  ^{Stargate: Atlantis Season 5 Episode 11: "The Lost Tribe"}

  It would appear as though the Vanir, though still possessing technology far beyond what humans have accomplished, aren't quite up to the standards of the Asgardians we encountered on SG-1.

• They lacked the ATA gene. You mentioned this in the question, but it's worth pointing out that not all Ancient technology required the presence of the ATA gene; the Stargates themselves are a prime example of this, and Carson nods towards it in the very first episode of Atlantis:

  Carson: We think the gene was used as a sort of genetic key, if you will, so that only their kind could operate certain dangerous or powerful technologies.

  ^{Stargate: Atlantis Season 1 Episode 1: "Rising, Part 1"}

  And in the third episode, we learn that some technology just needs to be "primed" by someone with the gene, after which anybody can use it:

  Grodin: It seems some Ancient technology requires the user to have the gene. Other things merely require initialization. Once activated, like the control room, anyone can push the buttons to make them work.

  ^{Stargate: Atlantis Season 1 Episode 3: "Hide and Seek"}

  Since the Attero Device certainly falls into the "dangerous and powerful" category, it makes sense that the ATA gene would be required to operate it, but it doesn't necessarily follow that the entire outpost would. Even if it did, however, there's no reason to believe it wouldn't behave similarly to the Atlantis control room: the Vanir could have kidnapped any number of Pegasus galaxy humans until they found one who could "prime" the station, and then dispose of them.