(CNN) -- After 61 days and no tangible evidence, officials from Malaysia, China and Australia will hunker down Wednesday to plot the next steps in the hunt for MH370.
Their tasks: Review all the information gathered so far and figure out what tools will be needed in the next stage of the search -- a deeper, broader probe of the Indian Ocean.
Two things are certain: This new phase will be expensive and even more difficult.
Australia estimates it will cost $60 million, with the breakdown of who's going to pay for what yet to be determined. But perhaps the greatest challenge now will be scouring unchartered territory. A key element of the new phase will be a detailed mapping of the ocean floor.
"We know that the water is very deep," Australian Deputy Prime Minister Warren Truss said this week. "And for the next stage involving sonar and other autonomous vehicles, potentially at very great depths, we need to have an understanding of the ocean floor to be able to undertake that kind of search effectively and safely."
The next phase will focus on 60,000 square kilometers of the ocean floor, a process that could take six to eight months.
Truss said he's not sure how deep the ocean is in the expanded search area because "it's never been mapped."
Search enters new, 'more difficult' $60 million phase