🎈🚀 What if you could send a satellite to orbit without a massive launch pad?
A Japanese startup called AstroX is doing exactly that — using giant balloons to carry rockets into the stratosphere, then firing them into space from 25 km above the Earth. The company just secured $15 million in Series A funding, and it plans to reach space by the end of 2026.
Here's how this unconventional approach could reshape the space launch industry — and why it matters for the future of affordable space access.
What Is Rockoon Technology?
The term "Rockoon" is a combination of "Rocket" and "Balloon." The concept is surprisingly straightforward: a large high-altitude balloon lifts a rocket to the stratosphere — roughly 20 to 25 kilometers above the Earth — and then the rocket ignites mid-air and blasts off toward space.
This idea actually dates back to the 1950s, when American physicist James Van Allen used rockoons for upper-atmosphere research. But nobody has ever used this method to put a satellite into orbit. AstroX aims to be the first in the world to achieve that.
So why bother lifting a rocket by balloon instead of launching from the ground? There are four key advantages:
Dramatically reduced air resistance. At 25 km altitude, air pressure is only about one-tenth of what it is at sea level. A rocket fired from up there encounters far less drag, meaning it needs less fuel and can be smaller and cheaper.
No need for expensive launch pads. Traditional rockets require massive ground infrastructure — launch pads, fuel storage facilities, flame trenches, and more. A rockoon system can launch from a ship at sea, eliminating the need for costly fixed facilities.
Weather independence. The stratosphere has stable conditions regardless of what's happening on the ground. Rain, wind, or clouds below don't affect a launch happening above them.
Flexible launch location. Since the balloon can be launched from virtually anywhere — especially from ocean-going vessels — the rocket can be aimed at any orbital inclination. This means satellites can be placed exactly where they need to go, without the costly orbital maneuvering that rideshare missions often require.
AstroX: From Fukushima to the Stars
AstroX was founded in May 2022 in Minamisoma, a city in Fukushima Prefecture. For those unfamiliar with the area, Fukushima is the same region that experienced the devastating 2011 earthquake and nuclear disaster. The choice of location is intentional — AstroX operates within the Fukushima Innovation Coast Framework, a government-backed initiative to revitalize the region through cutting-edge technology.
The company's CEO, Shotake Oda, is a serial entrepreneur who previously founded and sold multiple IT companies before pivoting to his childhood dream of working in space. His vision is summed up in the company's bold motto: "Reclaim 'Japan as No.1' in space development."
This might sound ambitious, but the technical team backing the vision is formidable. The CTO is Professor Yutaka Wada from the Chiba Institute of Technology's Space Transportation Engineering Lab, who has successfully conducted university-based rocket launches including offshore firing. The executive team also includes Takashi Maemura, who was the first-ever launch director for Japan's H-IIA rocket — one of the country's most reliable launch vehicles.
The Funding Story: From Seed to $15 Million
AstroX's fundraising journey shows rapid acceleration:
In December 2022, the company raised an initial ¥50 million (about $330,000) in a seed round. By September 2024, they completed a pre-Series A round of ¥400 million ($2.6 million). Then in November 2025, the Series A first close brought in ¥1.8 billion ($12 million), combining equity investment from firms like Alpha, Daiwa Corporate Investment, and DeepCore with debt financing from Abukuma Shinkin Bank, Mizuho Bank, and Sumitomo Mitsui Banking Corporation.
In February 2026, the company announced its Series A second close, adding investment from One Capital and Inclusion Japan, bringing the total Series A funding to ¥2.32 billion (approximately $15 million).
This rapid fundraising trajectory — from seed to a significant Series A in under four years — reflects growing investor confidence in both the rockoon concept and AstroX's execution capability.
Technical Progress: Step by Step Toward Space
AstroX has been methodically building toward its goals:
December 2022: Successfully conducted a model rocket mid-air launch from a balloon in Yamaguchi Prefecture, demonstrating basic attitude control during aerial firing.
August 2024: Launched the small hybrid rocket "Kogitsune" — developed in collaboration with Chiba Institute of Technology students — reaching an altitude of 300 meters and validating key offshore recovery techniques.
November 2024: Fired the much larger FOX-1 rocket (C1-2), a 6.3-meter-long hybrid rocket with capability to reach 10 km altitude, from the Minamisoma coastline. The rocket successfully reached 7 km, marking a major milestone.
December 2025: Completed the first launcher mechanism test, successfully deploying and separating a dummy rocket from the launch platform using a crane system.
The next major milestone is a Rockoon-mode suborbital launch — lifting a rocket by balloon to the stratosphere and firing it to reach 100 km (the Kármán line, the internationally recognized boundary of space) — targeted for 2026.
Why Japan Needs This
Here's a fact that surprises many people: despite being a major space-faring nation, Japan currently launches nearly 99% of its small satellites on foreign rockets. Japanese satellite makers have to wait in line for rides on SpaceX Falcon 9s or other overseas vehicles, with limited control over timing, orbital placement, or mission parameters.
The global space economy is projected to exceed $1.8 trillion by 2035, and the small satellite market is one of its fastest-growing segments. Japan's own small satellite market was valued at $329 million in 2024 and is expected to double by 2033. Yet without domestic launch capability for these satellites, Japan risks becoming dependent on foreign infrastructure for a critical strategic sector — much as it did with semiconductor manufacturing.
AstroX's rockoon system directly addresses this gap. By offering a low-cost, flexible, high-frequency launch option, it could give Japanese satellite operators the independence they need. The company targets launch costs below ¥500 million ($3.3 million) per mission — competitive with the cheapest options currently available.
The Bigger Picture: AstroX Is Not Alone
AstroX operates in a competitive landscape. Several other companies around the world have explored or are exploring rockoon-style launches:
SpaceRyde (Canada) has been developing a balloon-launched rocket system for small satellite deployment. Zero 2 Infinity (Spain) has tested its Bloostar system, aiming to launch micro-satellites from balloon platforms. Leo Aerospace (USA), a Purdue University spinout, demonstrated a rockoon launch in 2019 in the Mojave Desert.
However, none of these companies have yet achieved orbital insertion using the rockoon method. AstroX's combination of hybrid rocket technology, JAXA collaboration on attitude control systems, and partnership with construction giant Obayashi Corporation (which contributed anti-rotation technology used in building the Tokyo Skytree) gives it a unique technical edge.
AstroX's Roadmap
The company has laid out an ambitious but structured timeline:
- 2026: Achieve suborbital flight (100 km altitude) using Rockoon method
- 2028: Reach satellite orbital altitude (500 km)
- 2029: Begin commercial satellite launch services and target IPO
If AstroX hits these milestones, it would become not just Japan's but the world's first company to commercially launch satellites using the rockoon method.
A New Chapter for Japanese Space Ambitions
Japan has a proud history in space — from the H-II series of rockets to the Hayabusa asteroid sample return missions. But the country has struggled to keep pace with the explosive growth of commercial space, particularly the SpaceX-driven revolution in low-cost launches.
AstroX represents something different: a startup approach to a problem that Japan's traditional aerospace establishment has been slow to address. Based in a region rebuilding from disaster, led by an entrepreneur from outside the aerospace old guard, and backed by technology that nobody in the world has fully cracked yet, the company embodies the kind of bold, unconventional thinking that Japan's space industry needs.
Whether AstroX succeeds or not, the fact that Japan is home to a serious contender in the rockoon race is a sign that the country's space ambitions are far from over.
In Japan, there's growing excitement about AstroX and what its balloon-launched rockets could mean for the country's space future. Some see it as the return of Japan's innovative spirit; others are cautiously watching whether the technology can truly deliver.
How does your country approach space launch? Are there local startups trying unconventional methods to reach orbit? We'd love to hear your perspective — share your thoughts in the comments!
References
- https://prtimes.jp/main/html/rd/p/000000025.000101722.html
- https://astrox.jp/
- https://www.jaxa.jp/press/2024/12/20241203-2_j.html
- https://thebridge.jp/2026/02/astrox-raises-series-a-2nd-close-for-rockoon-rocket
- https://newswitch.jp/p/46649
- https://kepple.co.jp/articles/tab7xlv5ll
- https://en.wikipedia.org/wiki/Rockoon
- https://airandspace.si.edu/stories/editorial/rockoons-rocket-and-balloon-experiments
Reactions in Japan
The rockoon concept has been around since the 1950s, but nobody has achieved orbital insertion with it. The fact that AstroX is positioned to potentially be the world's first is genuinely exciting. Having the original H-IIA launch director on the team is a huge asset.
I had no idea a company like this existed in Minamisoma. After years of nothing but grim news since the earthquake, just knowing there's a space startup in our hometown brings me to tears. I want to support them however I can.
2.3 billion yen sounds impressive, but isn't that a drop in the bucket for rocket development? SpaceX operates on a scale of hundreds of billions. I worry about them running out of money before they reach their goals.
Our company's satellites have to rely on SpaceX too, with wait times over six months and no choice of orbit. We desperately need a domestic option with flexible scheduling. Seriously rooting for them.
An IT entrepreneur pivoting to space — has an Elon Musk vibe. But the funding scale is orders of magnitude different. This is a test of whether Japan's VC ecosystem can support deep tech. Series B will be the real make-or-break moment.
The combination of hybrid rockets and rockoon is technically brilliant. Hybrid engines use solid propellant with liquid oxidizer, so the explosion risk is low — ideal for balloon-launched systems.
Looking at the investor lineup — Alpha, DeepCore, Mizuho, SMBC — these are firms with real deep-tech judgment. Whether 2.3 billion yen is enough is a tough question, but with this backing, follow-on funding should be achievable.
The word 'Rockoon' sounds adorable, but what they're actually doing is incredibly cool. Float up gently on a balloon, then BAM — rocket ignition! It's like something out of sci-fi. I'd definitely go to a launch viewing event.
Honestly, Space One's Kairos is struggling and Interstellar Technologies still hasn't achieved orbit either. Japanese private rockets seem to be all hype with few results. I want to be hopeful, but track records matter.
Applying Obayashi Corporation's anti-rotation tech from the Tokyo Skytree construction to rocket attitude control — that's a brilliant cross-industry collaboration. This kind of lateral technology transfer is so uniquely Japanese.
I didn't know 99% of Japan's satellites are launched overseas. The thought of repeating the semiconductor industry's mistakes in space is chilling. Not just AstroX — Japan urgently needs to develop independent launch capability as a nation.
From a national security perspective, having domestic small satellite launch capability is critical. If we depend on foreign rockets during a crisis, we can't replenish reconnaissance or communication satellites. This civilian tech has major defense implications.
They're holding a recruitment event called 'Sushi Night' lol. Love the casual vibe for a space venture. Companies with this kind of culture are probably the ones that'll transform Japan's space industry.
My simple question: what happens if the balloon drifts in the wind and the launch position shifts? They say the stratosphere is calm, but there's significant turbulence in the troposphere during ascent. Seems like plenty of technical hurdles remain.
The JAXA ISAS collaboration on attitude control devices sounds unglamorous but is hugely important. ISAS has world-class balloon experiment expertise. This partnership is a major advantage for AstroX.
I work in Taiwan's space sector. The problem of not being able to launch your own satellites domestically? We face the exact same issue. If AstroX offers flexible launch services, Taiwan would be an eager customer. Looking forward to Japan-Taiwan space collaboration.
Canada's SpaceRyde is working on the same rockoon concept, so AstroX is very much on our radar as a competitor. Having an H-IIA launch director on the team is enviable though. And $15M in funding is significant for this niche.
Speaking as a NASA engineer, orbital insertion via rockoon is technically extremely challenging. Attitude stability during balloon separation, ignition reliability at altitude... the challenges are massive. But if they pull it off, it'll be groundbreaking.
ISRO is famous for low-cost launches, but rockoon could push costs even lower. If you can launch a satellite for under $3.3 million, space becomes more accessible for developing nations too. AstroX's success could be a beacon of hope for smaller countries worldwide.
German aerospace engineer here. The hybrid rocket plus balloon combo is excellent for safety and environmental impact. Small rocket development in Europe has been sluggish, so Japan's unconventional approach is a healthy wake-up call for us.
As a Nigerian telecom satellite engineer, the location-flexible nature of rockoon launches is incredibly appealing. Africa has no spaceports, so if you can launch from the ocean, we could potentially get our satellites into orbit directly.
Interesting tech, but I'll be honest — I'm skeptical. Neither Zero 2 Infinity nor Leo Aerospace achieved orbit. There's an enormous gap between concept and execution. I hope the Japanese team can prove the difference, but I'll believe it when I see it.
South Korea only recently gained independent launch capability with Nuri, and it took over a decade. AstroX is barely 4 years old. Startup speed is impressive, but rocketry is a field where you learn through failures. I hope they don't rush too much.
Former SpaceX intern here. Honestly, rockoon feels too niche. In the age of mega-constellations, can a payload-limited balloon method really scale? But for on-demand small satellite launches, there might be a viable market niche.
I live near Brazil's ALCÂNTARA space center. Knowing the impact that launch facility construction has on local communities, the rockoon concept requiring no ground infrastructure is brilliant from an environmental perspective.
China has its own launch capability, but our private small rocket sector is booming too. Chinese companies have researched rockoon methods, but nobody's made it work. I'm genuinely curious from a technical standpoint how far AstroX can go.
I work on balloon experiments at Kiruna Space Centre in Sweden. High-altitude balloon operations are harder than people imagine — wind prediction, burst risk, communication blackouts. AstroX partnering with JAXA's balloon team is a smart move.
I'm in Australia's defense industry. Responsive satellite launch capability has significant military value. A system that can launch quickly regardless of weather or location would be attractive to Five Eyes nations.
I work at ArianeGroup, and Europe has fallen behind in the small rocket market. The Vega successor is delayed. Japan entering the small satellite market with such a creative approach is both a competitive threat and a learning opportunity for us.