Rocket Lab Slides 5% as Space Names Give Back Gains; AST SpaceMobile Drops 6%, Planet Labs Sinks 4%

David Moadel

Fri, September 18, 2026 at 5:45 PM GMT+3 5 min read

Quick Read

Rocket Lab dropped 5% and AST SpaceMobile fell 6% Friday, with unrelated fundamentals pointing to sector-wide profit-taking rather than deal-specific news.
The space ETF (UFO) fell 2% versus just 0.2% for the S&P 500, confirming selling is concentrated in space names, not the broader market.
Rocket Lab's all-equity Iridium deal creates dilution drag that bites hardest when sector momentum cools; the FCC cleared a first regulatory hurdle this week.
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Shares of Rocket Lab (NASDAQ:RKLB) are sliding in Friday morning trading as space-sector names give back a stretch of recent gains. Rocket Lab stock is down 5% to $64.38, and the move looks like sector rotation rather than any company-specific catalyst.

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Peer action backs that read. AST SpaceMobile (NASDAQ:ASTS) is leading the group lower, with AST SpaceMobile stock down 6% to $58.68 despite having no role in the pending merger that ties the other two names together. In the same vein, Planet Labs (NYSE:PL) stock is down 4% to $16.27. Meanwhile, Iridium Communications (NASDAQ:IRDM) is drifting lower too, with Iridium Communications stock down 2% to $46.66 in the tighter band expected of a name locked into an all-stock deal.

Fund action shows the same divergence. The Procure Space ETF (NASDAQ:UFO) is down 2% in the session. By comparison, the SPDR S&P 500 ETF Trust (NYSEARCA:SPY) is down just 0.2%, so the selling is concentrated in space names rather than across the wider tape.

Peer Weakness Points Away From a Deal-Specific Story

If Rocket Lab were selling off on fresh news about the Iridium acquisition, AST SpaceMobile wouldn't be leading the group lower. The deeper drop in AST SpaceMobile, a name with no involvement in the transaction, points instead to the space complex repricing as a group after a strong run higher.

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Rocket Lab entered the day down 8% year to date (YTD), so this pullback isn't erasing a huge cushion for Rocket Lab holders. That's more consistent with high-beta space and defense names taking profits together than with a single-name story. Iridium Communications, tethered to Rocket Lab through the pending deal, is drifting alongside the group rather than pulling in its own direction.

The gap between the peers matters for how to read the day. AST SpaceMobile is running an entirely separate playbook, building out a low Earth orbit constellation for direct-to-device cellular service, and its capital cycle has nothing to do with Rocket Lab's launch and satellite business. When names with unrelated fundamentals fall in unison, sector flow is usually doing the work.

Iridium Acquisition Sits in the Background

Rocket Lab has agreed to acquire Iridium Communications, and the transaction has not yet closed. Rocket Lab stated this week that it has fully funded the acquisition through an equity raise, and 24/7 Wall St. reported on Thursday that the Federal Communications Commission (FCC) cleared a first hurdle on the transaction.

Funding the deal with stock is dilution for existing Rocket Lab holders. A market that has stopped worrying about whether the money exists is free to start weighing what issuing it costs current shareholders. That mechanical drag on Rocket Lab can coexist with strong sector enthusiasm, and it can bite harder on days when the broader space trade cools.

For Iridium Communications, the setup is simpler. Iridium Communications stock will trade in tandem with Rocket Lab until closing, and today's dip reflects the acquirer's session more than anything specific to the satellite operator's own network business. What still matters most for Iridium Communications holders is whether the deal actually completes, since the merger is what governs the exit price.

What to Watch Next

The open question for Rocket Lab is completion, not financing. Traders can watch for whether the FCC review continues toward a clean close, since regulatory checkpoints are the gating item for the combined-company thesis and the driver of any deal-spread math around Rocket Lab and Iridium Communications.

AST SpaceMobile is a different setup. Standalone bets on satellite direct-to-device connectivity carry their own beta, and today's move in AST SpaceMobile underscores how quickly these names can sell off when sector sentiment shifts. Shareholders may want to keep an eye on whether the space fund stabilizes into next week, since group-level flow tends to lead the individual names.

Investors sizing positions in Rocket Lab, AST SpaceMobile, or Iridium Communications should keep their exposure modest given how much ground these names have covered in recent months (we wrote a full playbook on speculating with a small slice of a portfolio, with the sizing and exit rules that keep it from hurting, in a free guide here). A pullback day in a still-crowded corner of the market isn't a verdict on any single company, but it's a reminder that space stocks can move together in both directions, and that momentum in the group can flip fast.

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