Can private-sector space business be profitable, or is it just an exciting way for billionaires to live out their fantasies?

Billionaires are fighting to launch wildly expensive business plans in a sector marked by failure on the frontier of technology.

We speak of the satellite internet business, a graveyard for ambitious ventures. Lately, a number of tech luminaries are prepping projects with more twists and backstabbing than a Habsburg family drama. The last time we checked in, itinerant satellite entrepreneur Greg Wyler had left Google to form a new satellite company, perhaps in cahoots with SpaceX’s Elon Musk. In the last week, news broke that Wyler’s start-up OneWeb has secured an investment from Richard Branson’s Virgin Galactic and Paul Jacobs’ Qualcomm to launch an internet satellite constellation, while SpaceX announced its own satellite internet plan—and a $1 billion investment round led by Google and Fidelity that valued the company $10 billion.

Official spokespeople for the companies are keeping quite mum on the details. That’s in part because of issues surrounding the radio spectrum companies license to transmit messages to and from orbit. Update, (1/23): While the International Telecommunications Union had described Wyler’s firm and Google as joint rights-holders to a block of satellite radio spectrum, Wyler tells Quartz that his company fully owns the spectrum and has no relationship with Google. As to possible arrangements to share that spectrum with the Google/SpaceX enterprise, Wyler says “my crystal ball is broken. Nothing is off the table, the mission is to connect people.”

We followed up with Google and SpaceX for further explanation of the underpinnings of these grand ventures. The responses, along with statements by Branson and Musk culled from other sources, were so vague that we’ve compiled and scrutinized them here in the hopes of understanding just how reasonable (or unreasonable) their ambitions are. Starting with the most plausible, and descending from there:

“Greg and I have a fundamental disagreement about the architecture. We want a satellite that is an order of magnitude more sophisticated than what Greg wants. I think there should be two competing systems.”—Elon Musk

Musk disagreeing with someone about sophisticated technology? Extremely plausible, especially when we’re talking about competition between a $5 to $10 billion, multi-thousand satellite constellation from SpaceX and a $2 billion, 648 satellite effort from OneWeb. That would more than double the existing number of artificial satellites orbiting earth.

“Space-based applications, like imaging satellites, can help people more easily access important information, so we’re excited to support SpaceX’s growth as it develops new launch technologies.”— A Google spokesperson.

Plausible…but why are we talking about satellite imaging when we asked you about your plans for satellite internet?

“This funding will be used to support continued innovation in the areas of space transport, reusability, and satellite manufacturing.”—A SpaceX spokesperson

Boom! A plausible middle ground in satellite manufacturing. It’s going to take a new, non-bespoke approach to building satellites to generate the quantity of satellites needed for these projects, something SpaceX has already experienced with rockets. OneWeb has promised a similar plan, but Wyler doesn’t have experience doing his own manufacturing.

“I don’t think Elon can do a competing thing. Greg has the rights, and there isn’t space for another network—like there physically is not enough space. If Elon wants to get into this area, the logical thing for him would be to tie up with us, and if I were a betting man, I would say the chances of us working together rather than separately would be much higher.”—Richard Branson

It seems plausible (as we’ll see later) that Musk’s SpaceX will compete for launch or manufacturing business from OneWeb.

“Mr. Musk appears to be trying to get around his lack of spectrum rights by relying, in part, on optical lasers.” —The Information

This technology seems about as implausible as Musk’s Hyperloop—as in largely theoretical—it’s still being developed by NASA. Musk has suggested that the optical lasers will be used to communicate among the satellites, not between them and earth. The Information (paywall) later reports that Google and SpaceX could use some of Wyler’s spectrum.

“We have the biggest order ever for putting satellites into space. By the time our second constellation is developed, the company will have launched more satellites than there currently are in the sky.”—Branson

Logistically implausible. Branson’s Virgin Galactic suffered a tragic loss while testing its SpaceShipOne in 2014, but even if that project wasn’t facing setbacks, it isn’t designed to reach orbital height. Branson’s proposed satellite-launching rocket will need to finish development and testing before 2019, when Wyler’s spectrum license runs out. If OneWeb does get a satellite constellation launched, it won’t be Virgin Galactic taking the lead.

“It will be important for Mars to have a global communications network as well.” — Musk

Implausibly…plausible?