Best Space ETFs

The long-term case for space is that launch costs have fallen dramatically, satellites now underpin communications, imaging, navigation, and connectivity, and new markets such as broadband constellations, Earth observation, and eventually deeper exploration keep expanding. It is a genuine multi-decade theme. But as a public-market sector it is young and thin: relatively few companies are pure space plays, many space businesses are still private or only recently public, and a lot of “space” revenue sits inside giant defense-and-aerospace contractors that also build jets and missiles.

That is why there are only a few dedicated space ETFs, and why they overlap so much with each other and with defense funds. The small pool of investable names means these funds carry concentrated positions, tend to be small in assets, and can be less liquid than mainstream ETFs. Space names can also be volatile and speculative, with several newer pure-plays still unprofitable. The theme can be real and the ride still be bumpy; none of this is a prediction about where space stocks go next.

There are essentially three funds built specifically around space. ARKX (ARK Space Exploration & Innovation) is actively managed, so a manager selects holdings not just in obvious space companies but across enabling technologies like AI, robotics, 3D printing, and advanced materials. That gives it a wider, more interpretive net and means what counts as “space” depends on the manager's view. It charges around 0.75%.

UFO (Procure Space) is an index fund that screens for companies deriving meaningful revenue from space, so it stays closer to the pure theme, with satellite operators, launch and hardware firms, and imaging companies weighted toward those with direct space exposure. It also charges around 0.75%. ROKT (SPDR S&P Kensho Final Frontiers) tracks an index that blends space exploration with deep-sea exploration, holds a broader mix that includes large aerospace-and-defense names, and is the cheapest of the three at roughly 0.45%. All three are small, and their holdings overlap.

A key thing to understand before buying any space ETF is what is actually inside it. Because the pool of pure-play space companies is small, these funds lean heavily on large aerospace-and-defense contractors (companies like Boeing, Lockheed Martin, and L3Harris) that earn only part of their revenue from space, plus satellite, communications, and imaging firms. So the space tilt is real but partial: you are often buying diversified defense and aerospace exposure with a space emphasis rather than a basket of dedicated space startups.

UFO screens hardest for direct space revenue, so it stays closest to a pure-space read, while ARKX and ROKT hold more diversified names. The practical effect is that these funds can move with the defense sector as much as with space-specific news, and the overlap between them (and with broad defense funds) is high. That is not a flaw, but it does change what you are actually exposed to, and it is worth checking each fund's current holdings before deciding. This is descriptive, not a recommendation.

The space funds split on approach. ARKX is actively managed: its team decides what belongs in the space theme and adjusts holdings over time, which can capture ideas an index misses but also introduces manager risk and can drift toward names that are only loosely space-related. UFO and ROKT are index funds that follow published rules, so their holdings are transparent and mechanical, changing only when the index rebalances.

Neither approach is better in the abstract. An active fund like ARKX gives you a manager's conviction and flexibility in a fast-moving, hard-to-define sector; an index fund like UFO or ROKT gives you a rules-based basket at a known methodology. In a niche where the theme is genuinely tricky to bound, both are reasonable, and the choice comes down to whether you want a manager's judgment or a transparent rulebook. Walnut is not an investment adviser, and this is descriptive, not a recommendation.

Costs are approximate expense ratios as of mid-2026; verify the current figure on each issuer's site. The first three are the dedicated space funds: ARKX is active, UFO is the index fund closest to pure space, and ROKT is the cheaper space-plus-deep-sea blend. XAR and ITA are not space funds at all but broad aerospace-and-defense funds included as adjacent, cheaper, more liquid options that hold space exposure inside a wider basket. For the broader picture, you can also explore the space economy theme or the individual companies in our best space stocks guide.

Because so much space revenue lives inside defense contractors, a broad aerospace-and-defense fund is a natural adjacent way to get partial space exposure. XAR (SPDR S&P Aerospace & Defense) uses a more equal-weighted approach that gives smaller names, including some space companies, more room, while ITA (iShares U.S. Aerospace & Defense) is market-cap weighted and dominated by the largest primes. Both are cheaper than the dedicated space funds, at roughly 0.35% and 0.40%, and far larger and more liquid.

The trade-off is purity. XAR and ITA are defense funds first: space is a slice alongside jets, missiles, and defense electronics, so they dilute the space theme in exchange for lower cost, more diversification, and easier trading. A dedicated fund like UFO or ARKX expresses space more directly but is small, concentrated, and more volatile. Which fits depends on how sharp a space tilt you want and how much single-theme risk you are willing to carry. Neither is better in the abstract; they are different levels of concentration.

The hard part of space is not picking the fund; among the dedicated funds, ARKX, UFO, and ROKT express similar themes with different methods, so cost, approach, and how pure you want the space read are the tie-breakers, and XAR or ITA are the choice if you want cheaper, broader defense exposure with space inside. The harder question is whether a narrow, volatile theme belongs in your portfolio at all, how large a slice makes sense, and how much it overlaps with defense or industrials you may already own. That depends on your holdings and goals, which is where an AI assistant that can reason over your real portfolio helps.

That is where Walnut fits. It connects your existing brokerage so you can ask, in plain language through Claude, ChatGPT, or a built-in assistant, how a space ETF would fit what you already hold, how much a position like ARKX or UFO overlaps with defense names elsewhere in your portfolio, and how these funds are doing against the market. Walnut keeps your accounts read-only, so a space position is only ever added when you place that order. As something that informs rather than advises, it sizes the question of a space sleeve against your real holdings instead of recommending one, because Walnut is not an investment adviser.

Space ETFs come from a small, overlapping universe. For a dedicated space tilt, ARKX (active, around 0.75%), UFO (index, closest to pure space, around 0.75%), and ROKT (cheaper space-plus-deep-sea blend, around 0.45%) are the three real options, and all of them lean partly on large aerospace-and-defense primes rather than pure-play space companies. For cheaper, more liquid exposure that includes space inside a wider basket, XAR and ITA are broad aerospace-and-defense funds worth knowing.

Whichever route, the honest framing is the same: space is a narrow, young, volatile theme with few holdings, so even a strong long-term story does not protect against sharp swings, which is why space is usually sized as a small, thematic slice. From a connected account you can dig into the space economy theme or the underlying companies in our best space stocks guide. Holdings, fees, and availability change; treat the specifics here as a starting point and confirm on each provider's site before deciding.