Helios outright owns the technology which enables the drilling of the asteroid, colony on mars, etc. This was from season 3. Dev invented the fusion engine that literally the entire mars colony uses, and helios is the sole provider of it. The base, the ships, the drilling crew, they are all helios owned. They own the energy, they own the base, they own the equipment, and they own the crew. Just because Helios would see an immediate return on investment, doesn't mean they also aren't footing the largest portion of the bill. In fact, the very reason they asked for $2 trillion in the first place, is because only they will be the ones supplying the equipment and man power at their own cost. Helios is a P3 entity. The reasons the US balks is because they only have a 2-term window for any president to take advantage of the asteroid, and Russia has no need since they already are cut in on the supply side of Iridium on mars.
This is made more clear by the role Dev has on the base. Officially, he's only below Danni as Captain, but Dev is officially simply a Helios employee. He's not actually any government official or anything. The only thing that gives him power up there is that he owns everything on mars.