Fox is aware that the operation will be challenging, especially as she is prone to seasickness. The icy conditions of the Southern Ocean whale sanctuary - ideal for minke and fin whales but inhospitable for humans - will be a test, although the chance to see icebergs at close quarters, she says, will be priceless.
However, she will be spending most of her time cooking, in the galley of the Sam Simon, Sea Shepherd's newest vessel.
She is putting potential confrontations out of her mind. "I can't think about it until I'm in the moment or it's happening at that time, and hope that whatever happens, it's all good," she said.
The secrecy surrounding her "call-up" was necessary, as Sea Shepherd was in the process of acquiring the Sam Simon, which Fox has been living on in port with the other 23 crew members.
The 56m ship began life as the Seifu Maru, an ocean research vessel used by the Japanese whaling fleet. Sea Shepherd said Japanese government officials failed to realise who was buying it.
The controls on the bridge are all labelled in Japanese and the former name remains on the side in raised metal outline.
About 120 crew members from more than 20 countries, most of them volunteers, will join Sea Shepherd founder Paul Watson in his latest bid to halt the whaling.
In an attempted counterattack, the Japanese whalers - in the shape of the Institute of Cetacean Research and the Kyodo Senpaku company - have taken legal action.
A court order issued by the ninth circuit court of appeals in the US on December 17 enjoined Sea Shepherd, Watson and anyone "acting in concert with them" from physically attacking the Japanese vessels or coming "any closer than 500m".
Gavin Carter, the whalers' Washington-based PR representative, says the order is to "ensure safety at sea".
Watson does not see it that way. "They are saying they are trying to protect their people from us. We've never injured any of them.
"They destroyed a US$1.5 million boat and almost killed six of our people," he said, speaking from the Steve Irwin at an undisclosed location. "[Yet] they didn't have to answer for it, they didn't have to pay compensation for it, they destroyed it and got away with it."
Each side blamed the other for the collision that sank the Ady Gil in 2010 but an investigation by the Australian Maritime Safety Authority was inconclusive and unable to apportion blame.
Watson says they are going to "use some imagination" in responding to the order.
They have time, as the Japanese fleet's departure has been delayed until mid to late January by a refit of the factory ship the Nisshin Maru.
Sam Simon
* Simon is one of the creators of the TV cartoon series The Simpsons.
* He is an animal activist, privately funding a shelter in his home town of Malibu, and donated the money that enabled Sea Shepherd to buy this fourth vessel.
* It will join the Steve Irwin, the Bob Barker and the Brigitte Bardot in the Antarctic campaign.
* Simon had been planning to join Operation Zero Tolerance but a cancer diagnosis ruled that out.
- Observer
