Firefly stock tumbled to close down 16.9% on Friday at $50.17. That's still $5 and change more than the initial public offering (IPO) price, but a lot of Thursday's IPO gains got vaporized as sentiment turned against the stock -- or perhaps it's more accurate to say, against space stocks in general.

Firefly Aerospace's ( FLY) stock is sputtering, just one day after its trading debut, when enthusiasm for the new listing sent shares soaring. The space company's stock was down 13% to about $52 Friday afternoon, wiping out more than half its gains in its first day of trading yesterday.

Firefly also boosted the size of the IPO. It will raise nearly $870 million from the stock sale. It is selling 19.3 million shares, up from an original proposal of 16.2 million shares. The stock will trade on the Nasdaq under the ticker symbol FLY.