Space stocks are certainly frothy ahead of SpaceX's widely anticipated initial public offering.

Not all shares of companies with a space business have moved, though, giving investors a way to play the next phase of space hype. And if growing excitement doesn't qualify as an investment, investors should at least know who could be affected by the SpaceX halo effect.

Elon Musk's rocket company is on the cusp of an IPO that could raise more than $75 billion and value his company at more than $2 trillion.

The IPO buzz and SpaceX itself have shown investors what's possible in space with low-cost rocket technology. SpaceX has created Starlink, a space-based broadband business that generates billions in operating profit annually. SpaceX is also pushing deeper into artificial intelligence, with ambitions tied to space-based data centers.

The IPO process has sent space stocks to the moon. Through midday trading on Wednesday, shares of Rocket Lab and AST SpaceMobile, the two most valuable pure-play space stocks, were up roughly 80% and 70%, respectively, over the past month.

The moves have left the pair, which are not profitable yet, trading at roughly 120 times and 420 times trailing sales. Pure-play space stocks, including those two as well as Planet Labs, Firefly Aerospace, Intuitive Machines, RedWire, York Space Systems, and Voyager Technologies, trade for an average of roughly 75 times trailing sales.

None of the companies is profitable yet. That hasn't bothered investors. The group is up about 450% over the past 12 months. (Some stocks that recently sold shares in an IPO don't have 12-month histories yet.)

SpaceX is the reason for the gains. "This is kind of the first time that the industry has really been cast in a more mature light, and perhaps a genuine repricing of the space sector as something here to stay," says Andrew Chanin, CEO of ProcureAM, which sponsors the Procure Space ETF.

Some of the valuation boosts will last, but not every investor can bring themselves to pay 80 times sales.

There are other companies with significant space businesses that might not rocket higher like Rocket Lab, but could still catch a bid as space fever heats up.

Airbus, Boeing, Safran, and Lockheed Martin are four. Airbus and Safran own half of Ariane Group, which provides space access for Europe. Boeing and Lockheed own half of ULA, which, before SpaceX, provided Americans with access to space. Boeing also has a space division, although trouble with its Starliner spaceship has dampened investor enthusiasm recently.

European nations are spending more on military space projects, says Micah Walter-Range, founder of Space Investment Services. Airbus, along with Leonardo SpA and Thales, is likely to benefit from any European Space Agency collaboration with America on moon projects, he adds. What's more, Northrop Grumman and RTX have played a role in NASA's Artemis II mission.

That group of eight trades for about 22 times estimated 2026 earnings and was up about 9% over the past 12 months, through midday trading on Wednesday.

Those aren't heavenly returns. "It will take a longer time for most of these companies to see benefits from the space rally," adds Walter-Range. "Investor focus seems to be on speculation that the pure-play space companies will win major contracts....I suspect the diversified space companies will [get] a boost when they actually announce large contracts, not ahead of time."

It might take actual space results to drive hidden-space stocks higher.

There might be one other hidden space stock: Alphabet. It might own a $100 billion stake in SpaceX, a consequence of its 2015 investment in the rocket company. Exactly what's happened to the stock isn't known. Alphabet's holding wasn't reported in SpaceX's IPO registration document, which only means Alphabet doesn't own 5% of the company. Alphabet didn't immediately respond to a request for comment about its investment.

Still, $100 billion is a lot, but it's only 2% of Alphabet's market value.