"I knew it was going to happen. I wasn't too worried about making it to the next round. It's just one more step," he told The Salt Lake Tribune on Monday. "I don't want to sound egotistical or anything, but I wasn't worried about the medical too much."
Sullivan's wife and children, who range in age from just under a year old to 13 years old, aren't exactly thrilled about the prospect of their dad rocketing off on a one-way trip.
READ MORE: Wife, daughter hope Utah dad doesn't leave them for Mars
"I don't like it, not at all," Kaitlyn, 12, said earlier this year. "When he leaves, I'd have a way to talk to him, but I can't ever see him in person again.
"It makes me sad because I'm going to miss him."
Her older sister Jocelyn, 13, takes a less-sentimental approach. Some aspects of the mission excite her.
"If he wants to go to Mars," she said, "he should go to Mars."
Sullivan's wife, Becky, has said previously she is still supporting her husband.
Ken Sullivan said it is "life as normal." He continues to work long-distance, piloting medical rescue helicopters in New Mexico and works seven days on and seven days off.
He is looking forward to interviews that are slated to take place later this year to continue whittling down the final group to the 24 who will actually make the trip to our solar-system neighbor.
"We're incredibly excited to start the next phase of Round 2, where we begin to better understand our candidates who aspire to take such a daring trip," Mars One Chief Medical Officer Norbert Kraft said in a statement. "They will have to show their knowledge, intelligence, adaptability and personality."
Mars One is a nonprofit based in the Netherlands dedicated to colonizing Mars, which depends on donations and aims to televise the mission to help fund it.
The group hopes to launch in 2025, though that may be pushed back as the ambitious project may meet unexpected road bumps ranging from the technology needed to sustain life on an inhospitable planet to finding people mentally stable enough to handle the thought of never returning to Earth, while getting along for the rest of their lives in a tiny living space.
More than 200,000 people originally applied for a chance to go. The current applicant pool consists of 418 men and 287 women, with the following geographic breakdown: 313 from the Americas, 187 from Europe, 136 from Asia, 41 from Africa and 28 from Oceania.
The plan for the mission is to send several groups of four people up every two years, when the Earth and Mars are at their closest points in their orbits, meaning a six- to seven-month journey. Each mission would bring up more supplies and equipment.
While Sullivan is champing at the bit to explore a new world, he still is conflicted about when he'd like to go.
"I may ask, 'Can I be on one of those last crews so I can hang out on Earth?' The only downside to that is that the very first crew is going to have the most challenges, and what's appealing to me is the challenges," he said. "But if I wait and go on a later mission, and that means I can have some of the challenges and still see my kids grow up a little more, that would be fine with me."
Five remaining Utah potential participants
Kenneth Ray Sullivan, 38,
Cody Don Reeder, 21,
Casey Hunter, 33, Murray
Katelyn Elizabeth Kane, 23, Provo
Will Joshua Robbins, 28,
Salt Lake City