Phoenix is our sounding rocket, which we have spent the last 12 months designing, building and testing. It will be launched on 2 or 3 November this year, reaching an altitude of around 9 km. Before the launch, the individual parts of the rocket must be carefully and structurally assembled. The final preparations are currently underway to ensure that the entire assembly process runs smoothly during the launch, with a particular focus on optimising collaboration.
Due to the presence of different systems, a rocket assembly consists of numerous stations in which all our technical teams have to work together in an integrated manner. We start with the tank as the central element of the rocket and assemble the corresponding hydraulic components. This includes the quick disconnect to the ground station, main and secondary valves, as well as sensors for measuring pressure and flow rate. Once this intermediate stage is in place, the combustion chamber is assembled together with the injector plate, paraffin fuel, igniter, nozzle, etc. This completes the lower part of Phoenix, followed by the nose cone and the fairing – which contains the recovery system and the flight computers. Last but not least, the fins and the boattail are added as aerodynamic interface elements at the height of the combustion chamber and Phoenix with a total length of more than 4.5 metres is assembled.
In our various test runs, we were able to develop a routine for the processes as well as estimate the time required: on average around 1.5 hours.
One of these montages were carried out in Bremen’s public space, at the Hanseatenhof. Despite the changing weather at that saturday noon, we and the interested viewers had a great time at this public assembly! Many passersby and children were able to ask their questions. Thereby we were able to represent our “City of Aerospace” Bremen in a special way while showing our own enthusiasm for space. We want to make learning about and the fascination for space reachable – not just for the technically savvy, but also for all the stargazers and creative space-dreamers.
All in all, we are very happy with our public assembly! Next comes the last days and weeks of preparation for the delivery from Phoenix to the Californian Mojave Desert, U.S.. The launch date is the weekend of November 2nd – November 3rd, 2024 between 3 p.m. and 8 p.m., german time.
We assemble the interstage, which is the main structural component connecting the combustion chamber and our tank.
Of course, our mascot Oktavia was also there!
Our team and Phoenix in the city after the successful assembly.
In May, the propulsion team of ASTRA achieved a very important milestone. The team successfully tested the propulsion system and fulfilled the requirements imposed by our system engineers for our future launch.
Our engineers at the Propulsion Test
I am Taro Tokita, currently the team lead of the propulsion team of ASTRA and I would like to tell you about the testing campaign of ASTRA’s new propulsion system. In simple terms, in the campaign we tested whether our engine works. As mentioned, the test was very successful and we were actually very efficient being able to hot fire twice on several days. But let’s start from the beginning!
Before we started with the actual hot fire testing though we had to pressure test our aluminium/CFRP (carbon fiber reinforced polymers) tank that the structures team of ASTRA made. Sadly, we experienced our biggest failure for the campaign here and the tank did not hold the required pressure of 90 bar (1.5 x). However, we were prepared for this situation and switched to the second tank that we brought which was made from steel and CFRP. This tank passed the test and so we could quickly continue our testing without longer hold ups.
Next, we characterized our injector plate with cold flow testing. These tests showed that our injector plate is kind of inefficient as it has a low discharge coefficient (this number describes the pressure drop that occurs when a fluid flows though the injector). As we realized later on this was actually better for us as this limited the oxidizer mass flow into the combustion chamber. Also, with these tests we leak proofed the setup and as there were no other anomalies we continued with the first hot fire test, a 2s burn!
For this first hot fire test everyone was nervous and slightly on edge. With all kinds of thoughts in our minds we assembled the test setup of the engine. After the last steps of sensor preparation were done, the team entered the control room to commence the filling operation of the tank. This was done via the ground systems in house built control unit. To our delight filling worked perfectly without any problems. Then, it was finally time to light the engine.
Countdown: 5, 4, 3, 2, 1,Ignition!
We saw the smoke from the Igniter exiting the nozzle. Then we saw how a lot of nitrous oxide exited the nozzle as well… For some reason, the fuel mixture did not catch on fire. This was confusing at first but after we took apart the motor, we realized that the problem was that one single Igniter did not produce enough heat to get the combustion reaction going. So this was an easy fix and we just used 2 Igniters. We assembled the system again and after the last steps of the setup we entered the control room hoping to see a flame this time.
Again, countdown: 5, 4, 3, 2, 1,Ignition!
Again, we saw the Igniters going off and then the engine fired and this was one of the most glorious moments of the campaign. We had no anomalies and no leaks, although the thrust generated was just slightly short of the target. By all accounts this was a near perfect result!
Our mascot Octavia after the test firing
The burn ended after 4s which is 2s more than what was planned. As we later found out, our main flow valve that controls the oxidizer flow into the chamber, cannot handle the liquid oxidizer flow and will only close as soon as the nitrous oxide changes to the gas phase. But now that we had proven that the engine works, we could continue testing and we directly went for a full duration test of 8s. We were able to replace the broken parts and the solid fuel grain and performed the next test on the same day. This test also showed no anomalies and therefore we could continue the campaign without any changes to the system. During the 3rd burn the nozzle partially eroded/melted so we replaced the nozzle with the second nozzle we brought. With the 3rd burn we also accumulated 2 similar thrust curves that we needed for one of the our launch requirements. Technically, we achieved our main goal.
With all subsequent tests we tried out different things. First, we included a Vortex plate that would mix the propellants in the chamber to increase efficiency. This worked very well for us and we also generated 2 similar thrust curves with this setup. This means that we could also fly with this setup at EUROC. Next, we also used a fuel grain that includes aluminium power. However, the powder was deposited in the outer most 2mm of the grain due to a centrifuge effect during the grain spinning process. Thus, this did not have a significant effect on the burn behaviour.
In the end we were able to perform 7 tests in 4 days, reached a peak thrust of over 7kN and fulfilled the requirements of our system. The next steps now are to evaluate all the data and to prepare for the launch at the end of this year.
I hope you enjoyed reading this blog entry and it gave you some insight about what is happening at ASTRA. Thank you for staying until the end, and don’t forget to expand your horizons!
For more information, pictures and videos: definitely check out our YouTube channel where a video about this testing campaign is published.
There is a saying in Bremen: „Drei Mal ist Bremer Recht“ (translated: Three times is Bremen law). In line with this, we had the opportunity, and seemingly the Bremen social responsibility, to exhibit at the Space Tech Expo for the third time this year. In recent years, we have been able to make an incredible number of contacts, gain experience and exchange ideas with experts. This time of the year we get to meet many of our collaborators, partners, sponsors and fellow rocketeers. The knowledge exchange we have is an unparalleled experience thereby making it one of the most exciting events of the year for ASTRA e.V to look forward to. A huge shoutout to Gordon McHattie for his constant support for our presence at the Expo each year!
So, we set up our booth again this year and took part in Europe’s biggest aerospace trade fair. With more than 7,500 visitors, we were able to spend three days in a row talking, gathering ideas and sharing our enthusiasm for space. This year was very special for us: We were able to exhibit the rocket we built for the first time! Explaining our design, the function and the construction of individual parts was much easier as our assembled rocket was displayed in the booth itself. At the same time, we were able to get direct feedback from colleagues, managers, engineers, scientists and many more. This is, of course, super valuable and constructive for us. As we are currently working on a design for our new rocket, Karma 2.0, having this feedback gives us the opportunity to receive and implement suggestions, ideas and criticism directly.
In addition to lots of ideas and incredibly great conversations, the Space Tech Expo means one thing: lots of fun! Of course, we also enjoy walking around and looking at innovative exhibitors, testing out fun offers or listening to exciting talks. After all, that’s what brings us all together at Space Tech Expo: endless interest and enthusiasm for space!
Anyone who reads our website, talks to us, or receives a flyer from us knows directly: We want to reach outer space. We want to build a rocket that flies to 103.6 km, thus crossing the border to space. To achieve this, we are developing and building all the systems for a rocket which can achieve this lofty goal.
But of course, safety is our top priority. That’s why it was clear to us from the very beginning that we would not simply launch our first rocket straight to 100 km. So what do we do? We decided to build a smaller rocket to test all of our systems and the design overall. This scaled down rocket would „only“ reach an altitude of about 3 km, but will give us the opportunity to test technology and gain the experience we need to reach our final target. Accordingly, we are focused on building this smaller rocket KARMA.
Over the last few months we have been working very hard to get closer and closer to this goal. We have completed many components, conducted countless tests of individual systems, and have also learned lots in the process. Then we applied to EuRoC 2023. EuRoC is a Europe-wide competition for student groups that build rockets. There you can launch different types of rockets to different target heights (3km and 9km). The rocket that most accurately reaches the designated target altitude wins the competition in its category
After a long application period and a lot of preparation, a part of our team traveled to Portugal on October 7th – together with our 3m long rocket in our luggage. On site, many more tests were carried out and our rocket was fully assembled. Our engineers tried to implement as much feedback as possible in the short time and to improve and eliminate shortcomings in the rocket. Unfortunately, the time during the competition was not enough to change as much of the design as would have been necessary for a launch. Our launch was cancelled and our ASTRAnauts traveled back to Bremen.
Of course, the trip to Portugal wasn’t for nothing. In the short time before and during EuRoC, we were able to make an incredible amount of progress in the development of our rocket. Through many tests we got a lot of opportunities to optimize details of our rocket. We will now collect the feedback we have received and take the time to incorporate it into our next design with one goal: to launch our rocket KARMA successfully in 2024!
If you want to watch a short video about us at EuRoC, click here:
The organizers counted around 65 participants at the first matchmaking event for aerospace, which took place last Thursday at the Digital Hub Industry (DHI) in Bremen. With this, the organizers – the Starthaus Bremen and the DHI in cooperation with ASTRA e.V. – have already achieved two of their three goals. At the first meeting of this kind, not only were local companies, associations and groups related to space travel able to present themselves. There was also a lively exchange and professional discussions.
Bremen is one of the top locations for aerospace in Europe. With more than 140 companies and 20 institutes in and around Bremen, the region is an important innovative location for space technologies. It is therefore no surprise that Bremen is also one of the few locations in Germany where young people can study space technology with a variety of specializations. This broad offering is a particular advantage of the location, but also brings with it some challenges.
So far, there are hardly any places where young scientists* from the engineering-technological field can have a professional and interdisciplinary exchange. Yet the young professionals are also looking for precisely such connections with each other and interdisciplinarily with other fields such as law, economics, logistics or biology. Because they want to combine innovation and sustainability. Having a space to develop prototype rockets, launchers, mini-satellites or other technologies themselves would be another big plus for Bremen as a location for the international community. It is precisely this kind of networked work, coupled with dedicated minds, that is urgently needed by the growing space industry.
In order to establish this link, we at ASTRA e.V. organized a matchmaking event in cooperation with the Starthaus Bremen & Bremerhaven and the Digital Hub Industry (DHI). First, the Starthaus and we introduced ourselves. This was followed by three different young start-ups from Bremen: Women in Aerospace, Astrait and Iorbit showed the whole breadth of what aerospace encompasses in their presentations. Well-known faces from industry and business also contributed. For example, guests included Holger Oelze (Managing Director of ZARM Technik AG) and Janusz Heitmann (DLR). Prof. Dr. Antonia Garcia from Bremens University of Applied Sciences emphasized the importance of such a bridge between young talent and companies or research. It was not just a matter of following lectures, but of getting to know each other in an open setting, exchanging ideas and developing ideas together.
After the stage program, there was time for discussion and lively exchange. In the process, we were able to make important contacts and find supporters. All in all, the event was a complete success with more than 60 active participants. Our conclusion is very unanimous: „This is exactly what we need. We’ll definitely repeat it.“
The biggest exhibition for the space industry of Europe “SpaceTechExpo” took place in Bremen again in November 2022 and ASTRA e.V. got to be one of the exhibitors! Every year this expo attracts exhibitors from the big players to small startups of the space industry who would like to present their ideas to an interested audience. This year was a special for members of space related student groups, because there was a group of booths at the SpaceTechExpo just for us!
Preparation for this event went smoother, because we already participated in 2021 and learned a lot from this. It was especially exciting displaying all of our new hardware protypes we were able to build in the last year. For the first time we had most of the final rocket parts to show to the public and this not only helped us getting more attention from curious persons, but also we got feedback and suggestions from some professionals or colleagues from other student groups. Directly next to our booth there was the Dutch student group DARE and the Swiss student group ARIS as well presenting their projects. Talking with everybody at the SpaceTechExpo in person with the hardware directly next to us turned out to be very valuable! This lead to new testing opportunities e.g. for the drop test we got support from KST regarding this and from DARE with their wind tunnel.
In the end these three days were tightly packed for us at ASTRA e.V. with booth duty, B2B meetings and talking to other people at their booth. But it was absolutely worth the efforts!
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