With all of the parts and components for our spacecraft ordered and on their way, we are currently going through rapid iterations of our design with a series of full scale builds. These engineering models help identify issues and challenges early, as well as test out how we can best assemble and integrate all of the different parts of the final build.
This progression from prototype to engineering model to flight model will be the main topic for us in the coming 12 months, as we bring everything together into one cohesive whole. The first flight models are starting to trickle in, allowing us to increase the fidelity of our qualification tests in the coming months.
Our testing facilities ensure that we can run almost all of our components testing in house, with the integrated full spacecraft test as the only one that we may outsource.
Apophis - God of Chaos
When we talk about near-Earth asteroids, we're talking about everything that co-orbits the Earth in a tight band around where we are, but with a distance to us that typically ranges in the millions to tens of millions of kilometers. Those distances vary massively over time due to the orbital dynamics of the bodies involved, like with asteroid Apophis which is set for a very close approach in 2029.
Named after the God of Chaos, Apophis is a 450 by 170m asteroid that will pass the Earth in a close fly-by that looks to be close enough to see with the naked eye. The ring of satellites that operate in geostationary orbit are orbiting Earth at a distance of 35,786 km, Apophis is expected to pass by underneath that orbit at a distance of 32,000 km. To be clear, Apophis will not hit Earth and will be flying by on its own orbit around the sun until it comes back for a closer fly-by in the mid 2030s.
Although that physical proximity sounds tempting, mission design shows that actually getting to Apophis during its close approach (not just snapping a speeding ticket but a rendezvous that would allow for interaction) will take a massive amount of energy due to the velocities involved. Looking at that specific timeframe, there are several dozen asteroids that are much farther away physically that are a lot easier to reach from an energy perspective. And Apophis is an S-type asteroid, which will be dry as a bone compared to the C-type asteroids that we target.
2025 TF
Similar to Apophis, the less dramatically named asteroid 2025 TF recently did a very close fly-by. Its closest approach was over Antartica, with an estimated altitude of about 430 km before it headed out on its way. With a diameter of just a couple of meters, it was only discovered several hours after it had already past on its way back into deep space.
Although it is unclear if this is the case with 2025 TF, Earth is known to have several of these small meter-sized asteroids not just co-orbiting but actually orbiting Earth as a mini-moon at any given point. These tiny objects are captured by our gravity well and can spend months or even years orbiting us, before either burning up in the atmosphere or heading back out again.
Detection remains an issue with how small and dark these objects are, but this mechanism where our gravity well functions like a giant vacuum that captures these objects naturally is fascinating and something we may very well look at for future missions.
Asteroids are awesome!
High Frontier Mission Update
Our primary mission objective for mission 1 is:
To rendezvous with an uncharacterized near-Earth Asteroid and showcase capturing regolith at kilogram scale, minimizing mission duration and cost.
We're launching in ~15 months on Transporter 19.
Budgets
We track our mass, financial, power and delta-v budgets in great detail as design drivers for our mission. We have caps in place for all of these that function as guardrails, but are always trying to optimize where we can. The cap for mass is 650kg, because that is the mass that we can launch under the launch agreement that we have in place for mission 1. We increased our margin across a number of the components in our mass budget, which increased until just under our cap. The increased mass also has an immediate effect on our maximum delta-v, which dropped because of the heavier spacecraft.
This mass-delta-v optimization is one that we will keep running until the very last moment, in part because we don't have a defined target that tells us with certainty how much delta-v we will need. Our current amount is more than sufficient for the top targets we are looking at, adding decent buffer to our mission design.
Mission Design
Building on the point about mass and delta-v in the prior section, the overview below shows fuel margin (how many kg of Xenon do we have left once we are at the asteroid) for 2 of our favorite targets across a number of different trajectories.
The graph starts after we hit Earth escape, which is ~7 months after launch given the spiral-out that we need to perform to get from our SSO orbit to escape. We looked at different start times to get a sense of sensitivity in different trajectories, with both targets showing healthy amounts of fuel left after we reach the asteroid. Interestingly, the total travel times are mostly similar for 2021 UH2 while there is much stronger variance for 2022 DC5.
This difference in travel times stems from the combination of Earth's orbit around the sun driving a starting position with the relative position of the asteroid at that time and at the moment of intersection/rendezvous. This assymmetry drives a lot of the nuances in how we pick targets and is one of the main drivers behind our push for a resilient, flexible target leaderboard instead of a single target.
Spacecraft
Our spacecraft needs to combine ultra-high performance (13 km/s of delta-v will make it one of the most powerful spacecraft to ever fly, especially with solar electric propulsion) with low mass and cost. And we also need it to come together rapidly, where many components will typically have lead times measured in years. This dynamic has been a key driver in our decisions for in house development, where we don't just look for alternatives for classic options that are 'aerospace' priced and scheduled but also fill in gaps in capability that simply don't exist in the market.
First off in that latter list are our solar arrays:
We are using a deployable carbon fiber boom combined with a foldable array blanket in a tensioned structure to optimize this blend between packing density, mass, deployed area and power. We are flying a ~10kW solar array, across 2 wings that each deploy a solar array blanket measuring 3.5 by 6 meters.
This will be the most mass-efficient solar array that has ever flown, with a power density for the entire array including deployment structure exceeding 150W/kg.
Our high gain antenna recently finished its test campaign:
Our distance to Earth when we are at our target asteroid will be somewhere in the 50-75 million kilometers. 'Near'-Earth asteroids...
To be able to communicate with Earth at that distance, we needed a high gain antenna that would provide enough RF power (measured as antenna gain) to still close our link budgets with a decent data rate. We are also limited to smaller ground station antennas on Earth, so the performance of this antenna is crucial to ensure we get our high resolution imagery and video back.
This antenna design is a fixed dish with a diameter of ~1m, made out of titanium for strength and stiffness because it needs to survive launch while sitting perched on the very end of our spacecraft. Very low mass as always, with a fixed form factor driven by the amount of volume we have available in our launch slot.
And our gimbal design is now flight-ready:
Our primary propulsion system is a series of 3 Hall effect thrusters, 2 of which are mounted on gimbals to ensure we have sufficient accuracy and momentum control in flight. The gimbal we designed provides a very high range of motion (30 degrees in either direction) combined with low mass and very high accuracy.
Mining in zero-g is also a capability that does not really have many market options, so our excavation development has been integral to our plans from the start:
Scoop, the system we are flying, combines buckets with a powerful bite to be able to crush through the material we find. After many iterations and improvements, the current version of the system is fully built out in metal and is mounted on a deployable boom that ensures sufficient stand-off distance from the asteroid surface.
Mission 2 scope and plans
As we get closer to our first launch, we're starting to work on subsequent missions as well to build out capacity for mass return. We have several agreements in place with customers to purchase fuel, starting with water deliveries for our first series of mass return missions.
We are building a larger spacecraft (~2x our current mass), with higher power (also ~2x), regolith processing capacity and return capability. We are leveraging all of our existing work, which translates into a lot of overlap between our first and second mission, with the biggest differences in primary structure, propulsion and our processing payload.
Our primary mission objective for mission 2 is:
To extract 1,000 liters of water from a near-Earth asteroid and return to GEO for customer delivery.
We're launching in ~27 months on a dedicated launch.
Regolith Age
Regolith itself as a material can be used structurally or as shielding mass, but currently has no direct applications beyond that. Our focus from a product development perspective is on consumables first, starting with water.
High energy pulsed laser blasting regolith, imparting force
We are also working on a number of more medium term goals, mostly around the idea of propulsion using regolith. The idea for that is quite simple, our second mission will require us to process 1,000 liters of water for customer delivery. Given the average water presence in C-type asteroids (5-10 mass%), that means we will be excavating much larger amounts of regolith and processing that material to extract the water.
The remainder, tailings in a classic mining sense, is discarded. But that mass is a multiple of our spacecraft and return material, providing an opportunity that can have a massive impact on our system efficiency.
Regolith tailings as deep space propulsion.
Our Q3 2025 Goals:
Our Q4 2025 Goals:
Thanks for joining us on this adventure!
The Karman+ Team