Heidi blasts off – Switzerland in Space, Episode 3

With its first home-made rocket, TELL, the Swiss Academic Space Initiative (ARIS) had already won an award for its air brake design. This was during the previous year's Spaceport America Cup, the largest engineering competition for rocket construction. The flight itself, however, was a complete flop.

Nevertheless, their efforts were not in vain, as the students behind the initiative used their knowledge gained from this disaster to achieve even greater results. The second HEIDI rocket was completed in March 2019.

If you want to know what HEIDI is all about and how a new rocket project is approached, check out Episode 2.

HEIDI in the Formula 1 wind tunnel and the first test flight

It's the end of March. The time has finally come. HEIDI is ready for testing, which causes a lot of stress. Paul, who has told me all about the project from his point of view, explains: «The last week of March was really tough. The first rocket tests were due and we glued the last tubes together on Monday. Unfortunately, we quickly found out that we had messed up – certain parts didn't want to connect.»

The team decided to work a night shift. They cut excess material to size before sanding and gluing everything again. At about one o'clock in the morning, they were done. A few hours later, at five o'clock, they showed up at work again.

«This had to be done, because on Wednesday afternoon a wind tunnel test was scheduled at Sauber, and the freshly glued rocket parts had to be put in the oven as quickly as possible so that they could harden by the following day.»

On Wednesday, first assembly of all rocket parts took place directly in front of Sauber's wind tunnel:

«We were very nervous because everything happened last minute, but the assembly went off without a hitch. HEIDI was put together inside Sauber's wind tunnel. Then, for three hours, the air brakes were repeatedly extended and retracted. We measured the drag generated by the deployed panels and how the rocket behaves at different angles of airflow.»

The collected data was transferred to a simulation of the upcoming flight after the wind tunnel tests. From this, new conclusions were drawn, which ultimately went directly into the control algorithm of the rocket.

Paul and his colleagues had no time to catch their breath. After the wind tunnel, there were only two days left to get ready for the first test flight. This took place in the canton of Jura, not entirely ideal from an organisational point of view. Switzerland has strict regulations. Among other things, you need a field that is twice as wide as your flight altitude.

As you can see in the video, the test went well. The parachutes opened as desired. Only the students suffered a bit, as nobody thought of bringing along some tents. The first sunny day of the year left many a face beaming with sunburn.

On to the deserts of New Mexico

After the tests, the team had about two and a half months left to optimize the rocket and prepare for the Spaceport America Cup. Among other things, transport of the parts to the USA also had to be arranged. To avoid problems with customs, the engine is bought in the USA and delivered directly to New Mexico.

And then it's finally time – the team travels to El Paso on the night of Saturday the 15 of June 2019. They got rental cars and drove to the edge of the desert near Las Cruces. A settlement consisting of fast food places and a shopping centre. Aside from the rocket launches, which take place a few kilometres further into the desert, this is where it all happens. The reception and award ceremony take place here. In addition, all teams can present their projects in a huge hall and talk shop about them. There are also panel discussions – networking is almost as important in this competition as rockets themselves.

On site, the students assembled the rocket and checked all systems on Sunday. They paid special attention to the most integral components, testing the recovery system and air brakes. The tests continued until Tuesday morning. To be on the safe side, the students also went to the desert to rehearse assembly at over 40°C during this time. Thankfully, thermal expansion of the components isn't too strong and everything fits together.

Tuesday afternoon brought along a round of questions with judges and a critical safety check of all parts. A smashing success. This cleared the way for HEIDI and gave the students until Saturday to complete their flight. A slot on Wednesday is considered.

Then everything happens at once. On Tuesday, testing and simulation continues deep into the night. After a few hours of sleep, the students leave for the desert on Wednesday at four in the morning. They bring all the equipment, the rocket, three pavilions, food and enough water for everyone to drink six to eight litres a day. So that nobody forgets to drink, the safety officer is appointed head of drinking without further ado. From then on, every 15 minutes, he reminds all his colleagues to drink at the top of his lungs.

Camp setup and assembly of the rocket follows, but still without an engine. The rocket is ready at 1:00. And the students are tired and out of energy. Everyone's nervous, nobody can think properly. And all this in extreme heat. Some even take a spontaneous nap in a camping chair.

When a strong thermal wind comes up, the team decides to postpone the launch until Thursday. Most of the team drives back to Las Cruces in the evening to get at least a few hours of sleep before the big day. Meanwhile, the project's fuselage team spends the night in camp beds to guard the rocket.

HEIDI's big day

Launch day again starts in the middle of the night. The team gets up at 2 a.m., as they want to perform the obligatory (second) security check before the flight, at 5 a.m.

After an hour and a half drive to the camp, the team subjects the rocket to another visual check. Then they install the engine and seek out the Spaceport America Cup security crew. At half past five, Team ARIS gets the green light. Now HEIDI can fly. The rocket is loaded onto a small transporter and driven to the launch pad.

Paul tells me how he experienced the last few hours before launch:

«On that day, time no longer existed. Ten minutes felt like two hours. I couldn't tell you what took how long. When you work so long for one moment, the world seems exceedingly unreal. But sometime shortly before ten o'clock it was time and we were finally on.»

Paul is up. Shortly before launch, his systems engineer decides that he wants to follow the spectacle as closely as possible. This engineer would have had the honour of pressing the start button from a few hundred metres away. An honour that now passes to Paul. An unforgettable moment:

«When I think about it, I still get goose bumps. I stood in the start tower and could hardly function due to all the tension. Everything felt surreal and I didn't even manage to turn the key for the cap of the start button. Fortunately, I was helped by the local launch tech. When the countdown for HEIDI was running and I pressed the button, I felt the mighty sound of HEIDI's engine in my stomach. I overjoyed.»

HEIDI flies as desired, and the team has three reasons to cheer. During the successful launch, at the opening of the main parachute and at touchdown. Although no one knows exactly how well HEIDI performed in the overall standings, no one can hold themselves back anymore. After months of work, all tension is released – the team is rapturous with joy.

Team ARIS gets lucky: HEIDI takes second place

Flight analysis shows that HEIDI missed its target of 3,048 meters (10,000 feet) by seven percent. The engine performed eight percent weaker than planned. Furthermore, the acceleration forces were 2 g stronger than expected.

A really good result. In the overall ranking, the flight collects slightly more than one third of the total number of points. Two days later, Team ARIS finds out how well it actually went at the awards ceremony. The Swiss students score 268 out of 350 points for their flight. The remaining points are awarded for engineering, technology documentation and the recovery system.

Even the appearance of the team is included in the evaluation. Thanks to the Cubesat system used and the early launch on Thursday, the team also scores 100 bonus points. This puts HEIDI in second place among more than 50 competitors in this category. Over all categories, Team ARIS took fourth place among 122 teams.

Way to go!

Coming soon: ARIS' first supersonic rocket

Team ARIS has reaped many laurels. But this is no time for relaxation. The next rocket is already being conceived. However, the students want to go even higher with this one. Thus, the rocket EULER is to reach three times the previous height in June 2020. Lets see if we can break the sound barrier and fly to exactly 9,144 meters (30,000 feet).

You can find more information about the supersonic rocket EULER here.

Want to read more rocket stories? Then support the topic or article with a like and click on the «Follow Author» button.