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Q&A – Dawn Aerospace Aims to Launch Satellites Multiple Times Per Day

By Doug Messier
Parabolic Arc
September 15, 2023
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Q&A – Dawn Aerospace Aims to Launch Satellites Multiple Times Per Day
Mark II Aurora subscale test vehicle during a flight test.
Image credit: Dawn Aerospace.

Dawn Aerospace is a New Zealand company developing a rocket-powered spaceplane designed to launch satellites during its twice-daily flights. The company also produces spacecraft thrusters used by satellite manufacturers around the world. Parabolic Arc sat down with CEO Stefan Powell during last month’s Small Satellite Conference in Utah to discuss the company’s progress and future plans. The interview has been edited for length and clarity.

Stefan Powell: Do you want the spaceplane side, the in-space propulsion side, or a bit of both?

Parabolic Arc: Both. You can start wherever you want.

Powell: We’ll start with the spaceplane. So, we did these three flights in three days in March this year. That was kind of our minimum viable rocket-powered aircraft to really show that it was certifiable, it was operatable, and that we could do it all within our current certification.

Parabolic Arc: Describe the vehicle.

Powell: The vehicle [Mk-II Aurora] is about four and a half meters long, about 2.4 meters wingspan, it’s about 250 kg at takeoff in its current configuration. It’s got a pump-fed peroxide-kerosene engine, about two and a half kiloNewtons of thrust. Throttleable, it can also fly in mono-prop mode, so that’s at about 1,700 Newtons of thrust.

It has these two operational modes. We take off from a conventional runway about 800 meters long in Glentanner in New Zealand – that’s kind of a central part of the South Island where there’s not too much air traffic. But, it’s still uncontrolled airspace. It’s not exclusive, we’re not excluding other airspace users from it. Our certification allows us to fly in that way.

These first few flights, it was really just to show that we could do this safely, we could get the aircraft in the air. It was not about getting high performance, high altitude, or high speed, just showing that we could do it. So, we’d fly up to about 8,000-ish feet, cut the engine, and then glide back home.

We also demonstrated that we can do a bipropellant takeoff. So, the most challenging part of the whole sequence is actually the takeoff roll, where you’re at high thrust and accelerating at pretty close to one G, and then pull up, and then fly away. So, the highest performance flight that we did was 10 seconds of biprop takeoffs. That got us up in the air and sort of accelerating up and away pretty quickly. And then we cut the engine to just sort of limit the maximum altitude and maximum speed that we got to.

Parabolic Arc: This is a scale model. How large would the actual [orbital] vehicle be?

Powell: Right now we’re saying, for about a 300 kilogram to-orbit payload, two stage to orbit, the first stage with the second stage is going to be about 25 tons. That’s what we think. Now, I wouldn’t say we’re beholden to that 300 kg mark. The market is changing every year, so when we actually come to design the Mk-III, we’ll reevaluate that. It roughly scales linearly with that payload size, but it probably wouldn’t be below 300 kg. The idea of going to that payload size is just we just want to go to the minimum payload size where we think the vehicle is viable. The idea is to keep that first commercially viable vehicle as small as possible.

Now I say commercially viable for the launch market. We actually think we can get the Mk-II to be commercially viable as well. Getting to space twice in a day and being able to access it for a really low cost – this is not millions of dollars per flight.

Parabolic Arc: You mentioned Mk-II and Mk-III. What are you flying now?

Powell: We’re flying the Mk-II. That’s why we call it the Mk-II Aurora.

Parabolic Arc: The Mk-II would be able to launch how much?

Powell: That has a small payload of about 5 kg. Just suborbitally; that’s not getting anything into orbit. The point of the Mk-II is really to be a technology demonstrator. It has the same amount of delta V as what a first stage has with a payload. So, it can fly roughly the same profile as what a Falcon 9 first stage does. So, the Mk-II will be able to fly up to 100 km altitude, reenter, turn around, come back, and land on an airfield – and then be able to refuel and fly again the same day. We think it’ll be the first vehicle to ever be able to fly to space twice in a day.

Mk-II engine hot fire. Image Credit: Dawn Aerospace.

Parabolic Arc: Is the payload with the second stage inside and it gets released? Is that how it works?

Powell: So, for the Mk-II, it’s captive payloads only. But for the Mk-III, there are a few different concepts of how you can actually do it. There are concepts of having it on the back of the aircraft, on the fuselage or under the fuselage, or like a fairing splitting open. We haven’t confirmed exactly which concept we’re going for, but we have a few.

Parabolic Arc: What’s the next step? Are you going to be flying a Mk-II additional times?

Powell: Yeah. So like I say, these first flights were just kind of like the minimum viable flights right under rocket power, after doing 48 flights on jet power. We’re now upgrading the whole airframe to be able to handle supersonic speeds and making some upgrades to the engine as well. So, with this version of the Mk-II, we’re calling the M-IIA, and that’ll be able to fly to about 70,000 ft and just through Mach one.

But, this version of the aircraft was really built like a brick shithouse. There’s a lot of extra carbon in there to just handle extra load cases, the unknowns that we had at the early stage of the project, and provisions for jet engines on there as well.

So, the Mk-IIB is the vehicle that we’re designing now, it’s aerodynamically identical. From the outside it’ll look identical to the Mk-IIA, but on the inside, it’s a much more optimized structure. Fuel tanks are now wing box tanks in the wings. Much more space for more peroxide. So we get much, much longer burn times, and a much lighter airframe. So, the Mk-IIB will be the first vehicle to be able to fly above 100 km. Also, it has a full RCS system as well to be able to handle reentry.

Parabolic Arc: What’s the schedule for that?

Powell: Yeah, so Mk-IIA will be doing maximum performance flights [around] Q1 of 2024. We’ll have Mk-IIB flying shortly thereafter, and we hope to be getting to spaceflights twice in a day sort of by the end of 2024.

Parabolic Arc: And the next step after that?

Powell: Once we’ve gotten to that and we’ve sort of completed this world burst of getting to space twice in a day, we think we’ll have the conviction to actually go design the Mk-III properly and then go raise money around that. That’s already starting to happen. We’ve already learned a lot about rapid reusability and what that means for operations and how that flows down into design. Also, how to certify these is a major, major part. We’ve talked a lot about the technology of the aircraft itself. But this is not a rocket with wings. This is very much an aircraft with the performance of a rocket. So, it needs to fly from an airport. It needs to be certifiable as an aircraft.

There’s a huge amount of learning that we do at the subscale that applies directly to that larger scale. And so we’ve already done a lot of that learning on how to actually design a rocket-powered aircraft to be certifiable. So, yeah, we’re kind of slowly starting that Mk-III design now, and we hope sort of by the end of ‘24, we’re starting to lock that in as we conclude the Mk-II program.

Parabolic Arc: Khaki [Rodeway] told me the other day that some of this comes from the [XCOR’s] Lynx [suborbital spaceplane]. I didn’t know if that was a brag on her part or if that’s true.

[Editor’s note: Rodeway is former XCOR who now works for Dawn Aerospace.]

Powell: Well, in 2013, a bunch of us actually toured through XCOR’s workshop at the time and spoke to Doug Jones and the crew there, and they showed us their pump-fed engines and very cool stuff. Very, very inspirational. I would say at least a little bit of that philosophy has come across to us.

Parabolic Arc: Any specific technologies, or just more of a design philosophy?

Powell: Certainly, they were very much into copper saddle jacket engines. I would say that was probably something that we picked up on just saying, “Look, we don’t want to deal with metal fatigue problems in high-cycle engines,” and this was one way around that. So, we also use copper saddle jackets and consequently we’ve never had problems with cracking or anything in our regen channels. Our engines seem to be pretty solid. We’re pretty happy with them.

Parabolic Arc: How reusable would this be? How many flights? What are you aiming for between major overhauls?

Powell: Well, we believe the reusability kind of follows from reliability, right? If you don’t have more than a 99 percent reliable vehicle, then it’s also not going to be better than 99 percent reusable because statistically, you would have crashed it by then anyway. Reliability is certainly the main thing there, so the whole architecture is really just built to be highly reliable. There are only very small parts of the flight envelope where if you had an engine out you would actually lose the aircraft, because you can always turn around and glide and get the vehicle back.

So, aircraft are typically about 10,000 times more reliable than even the best rocket. I’m not saying we’ll be able to achieve typical aircraft reliability because we still have some slightly more challenging aspects to it, but if we could get it 100 or 1,000 times more reliable than a rocket, then that kind of suggests we can probably get into the realm of thousands of cycles, as a ballpark. So that’s kind of how we think. We think at least 1,000 reuses is kind of realistic.

Parabolic Arc: Do you foresee operating a fleet of these around the world?

Powell: Exactly. I mean, that’s the whole model, right? You get away from having to reproduce your hardware for every flight or even every 10th flight, and you really just go to operating a fleet at high frequency.

Parabolic Arc: How much have you raised so far?

Powell: We’ve raised about $20 million US so far on the spaceplane program alone. We’ve spent about $7 million US. So, it’s pretty modest.

Parabolic Arc: Are you looking to do another raise soon?

Powell: No, I mean this is where the in-space propulsion side of the business becomes interesting because that side of the business is already profitable. So that’s certainly fueling our R&D efforts to some extent. Now that’s a reasonably recent phenomenon that it is actually profitable but over the last four years we’ve typically been about 50 percent VC, 50 percent other revenue sources so grants and sales and whatnot.

1N thruster undergoes acceptance testing. Image credit: Dawn Aerospace.

Parabolic Arc: Can you describe that more?

Powell: The in-space propulsion is all about hydrazine replacement. So, actually, even take a step back from that. Why do we do in-space propulsion? How does this tie into the spaceplane thing at all? We want to consider the space transportation problem from the start of life, which starts on the ground, to very much the end of life, which is the disposal of the spacecraft.

If you consider the in-space mobility aspect in conjunction from Earth to space and from space to whatever else they’re doing, consider these problems as one you can come up with much, much more efficient solutions. So, we’re really trying to trend towards more and more reusability on the spaceplane side. That’s reusing as much of the first stage as we can. Eventually, that’ll be second-stage reuse, but that’ll probably be the last aspect to be reused.

After the first stage is reused, I think the next thing to reuse is actually the in-space segment. So, we need to start thinking about in-space technologies, in-space propulsion technologies that are going to lend themselves well to reuse, to putting huge amounts of propellant through thrusters over long periods of time. Anything with a catalyst is pretty limited in terms of its life. Eventually, that catalyst gets poisoned, and it doesn’t work very well.

Parabolic Arc: So, You’ve been selling propulsion systems. Who have you been selling them to?

Powell: Yeah, absolutely. Tons of customers. We really started designing these thrusters in about 2016, 2017. We had that first on orbit in January 2020, I believe. Yeah, it seems like so long ago now. So again, that first B20 in space was on D-Orbit’s ION Mark II OTV [orbital transfer vehicle]. I think they’re up to number eleven [OTVs] now. So, there are ten sets of six thrusters on there, so 60 thrusters of ours on their vehicle. They’ve been our most prolific user that’s actually gotten them into space so far, but we’ve delivered a bunch more.

We’re currently producing about seven thrusters a week. We have about 200 on order. And I mean, you can look it up on the website, but it’s all kinds of users. Lynk was a good example, we’re providing a propulsion for them now. Lynk is building a communication constellation. Pixxel is another one. They’re building a hyperspectral constellation. The Indonesian space agency is one. Blue Canyon is buying them as well.

70 kNs SatDrive satellite propulsion system. Image credit: Dawn Aerospace.

Parabolic Arc: Can you tell me what they’re powered by?

Powell: Nitrous oxide and propylene.Yeah. So, like, very simple propellants, but still very high performance. You get in the realm of 280 seconds of ISP.

Parbolic Arc: They’re not toxic, are they?

Powell: Exactly, not toxic. Nitrous oxide is in every hospital in the country, and propylene is pretty much barbecue gas so it’s not exotic. We were able to accept and test all of our thrusters in-house, literally in workshops next to the CNC shops because the exhaust is not hard to handle.

Parabolic Arc: Getting back to the spaceplane, do you have even a rough schedule of when you expect to be able to launch a small satellite?

Powell: Not really. We haven’t really started the project in earnest yet. And … a schedule is so dependent on how we go with fundraising and also on how we end up commercializing the Mk-II. There’s just so much interest in that. Now, this is going to be an entirely unique capability that we can offer at a very low price point. So, we’re already seeing lots of customers are actually quite interested in using that.

Parabolic Arc: This is suborbital, right?

Powell: Correct, suborbital.

Parabolic Arc: What kind of uses?

Powell: I mean, all kinds of things like microgravity research, signal intelligence is certainly another one. All kinds of tech demonstrations, flying custom G profiles. So, testing Mars hardware, we can fly quite long G profiles at like 0.3 g or whatever you want. So many applications. This is so much more capable than a standard suborbital offering.

But this is really an entirely unexplored market because no one’s been able to offer a service at such a low price, and also such high temporal resolution. We can fly multiple times a day. Say you wanted to do an atmospheric measurement at altitude at sunset every day because you want to observe a phenomenon that happens at exactly that time. You can literally do that every day. That’s not a challenge for us. That’s fine.

Parabolic Arc: You wouldn’t be able to do that with Blue [Origin] or Virgin [Galactic].

Powell: Exactly. You can’t practically do that with sounding rockets. Not at a reasonable cost. You couldn’t do that with Blue [Origin]. It’d be a challenge even to do that with balloons just because of how uncontrolled it is and the limited altitude that they can reach. So, things like space weather is also a topic. Lots of domains that are pretty poorly explored because there simply just isn’t a service like this. So it’s somewhat challenging for us to actually gauge how well that’s going to go.

Parabolic Arc: Is there anything I haven’t asked about?

Powell: We’re getting pretty close to being a profitable company now. It’s certainly hard to raise money at the moment, but we’re not too concerned about that.

We’re really just putting a lot of effort into scaling up our propulsion system production. We’ll produce about 20ish systems in the next six months that we’ll deliver to customers and that’ll continue to scale up from there.

We’re about 130 people at the moment. There are about 45 or so working on the spaceplane. The remainder working on in-space propulsion, manufacturing and marketing, and whatnot.

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