Denmark’s DIY Space Program

Phillip Keane | Comments | January 25, 2017

It seems that every billionaire is getting bitten by the spacebug these days. Folks such as Sir Richard Branson, Elon Musk and Jeff Bezos are all keen to get a slice of that delicious cosmic pie…Honestly, it’s probably a lot easier to develop a spacecraft if you have a few billion dollars in the bank. But what if you want all the Buck Rogers, but lack the actual bucks to make it happen?

Budget space company Copenhagen Suborbitals belongs to this latter category of space explorers and is making the most of CAD tools in order to reduce development costs, all with the lofty aim of launching a person into a suborbital trajectory onboard a DIY spaceship.

It’s the modern-day equivalent of the Mercury Redstone project, which you may recall as the project that put the first American (Alan Sheppard) into space. But naturally, Copenhagen Suborbitals lacks the budget of NASA.

Founded in Copenhagen in May 2008, Copenhagen Suborbitals claims to be the “world’s only amateur space program.” The focus of that expression is of course on the word “amateur”…because the 50+ staff at Copenhagen Suborbitals are all working as volunteers, many of whom have actual full-time day jobs as well.

Roadmap

Looking on the Copenhagen Suborbitals website, you can see that it has a fairly extensive roadmap, detailing milestones that must be passed before it finally straps somebody into a rocket.

HEAT-1X
The first successful launch by Copenhagen Suborbitals was in 2011 and featured the HEAT-1X rocket, carrying the Tycho Brahe mini-spacecraft and a human-sized crash test dummy within. The rocket itself was a hybrid epoxy/nitrous oxide fuel mix and was launched from a mobile platform at sea, marking the first time an amateur organization had performed such a sealaunch. Although the HEAT-1X mission was not entirely successful in terms of reaching its goals (the engine needed to be shut down early in the flight trajectory), there were enough useful lessons to be learned for future developments, particularly in terms of the operational and safety sides of things.

image001(Image courtesy of Copenhagen Suborbitals.)

Nexø I

The most recent tech demonstration from Copenhagen Suborbitals featured the Nexø I rocket, which was launched in July 2016. The Nexø I is a small-scale demonstrator that is intended to prove components and systems for the full-scale Spica rocket, which is the final version that Copenhagen Suborbitals intends to use in order to put an astronaut into space.

Nexø I is the first liquid bipropellant rocket launched by Copenhagen Suborbitals and uses a custom-built engine, dubbed the BMP5.

image003Jet vane and servo mount, designed in SOLIDWORKS. (Image courtesy of Copenhagen Suborbitals.)

Cutting costs with CAD

While designing a rocket may seem like a somewhat daunting task, Copenhagen Suborbitals does have access to something that the folks on the Mercury Redstone project did not: CAD software and simulation packages.

As readers of EngineersRule.com will know, access to CAD can reduce the time taken to bring designs to life, and simulation can help to identify problematic areas and implement changes before a design is even finalized—and, indeed, before a single piece of metal is cut.

Copenhagen Suborbitals has done just that and has been taking advantage of the capabilities offered by SOLIDWORKS from the original drawing and conception phase right through to CFD simulations.

The eDrawing image below shows the Launch Escape System (LES). The LES fits on top of the rocket and, in the event of an explosion, fires itself skywards, carrying the spacecraft capsule and occupants away from the explosion and to safety. Think of it like an ejector seat.

image005Launch escape system shown in SOLIDWORKS eDrawings. (Image courtesy of Copenhagen Suborbitals.)

Using SOLIDWORKS, Copenhagen Suborbitals has designed the capsule model, exported the drawings for laser cutting and performed Finite Element Method (FEM)analysis of structures to ensure that the capsule structure is capable of meeting the requirements for the launch environment.

Within SOLIDWORKS Simulation, it is relatively simple to model the g-loads experienced by a spacecraft or rocket during launch. It is a simple case of finding the maximum accelerations the rocket will experience and then adding those forces as a load within Simulation. Von Mises plots, displacement plots and the usual FEM plots can then be plotted, showing the stresses and strains that will affect the vehicle.

Any weaknesses shown within the plots can then be reinforced and designed out.

In the early days of spaceflight, such simulations would have been impossible, and engineers would have had to perform hideously complicated calculations by hand and then see if the calculations were accurate by building and testing the hardware.

FEM helps to reduce the design and build time significantly by providing visual cues as to where the weaknesses will occur in the structure.

In addition to the solid mechanical aspects of simulation, Copenhagen Suborbitals used SOLIDWORKS flow simulation to help pinpoint the center of pressure for its rockets. This is usually not a difficult thing to determine for basic geometries; however, the unique shape of the spacecraft capsule adds a layer of complexity to the design work. The Flow Simulation package in SOLIDWORKS enabled Copenhagen Suborbitals to determine the point where the torques acting on the spacecraft were equal to zero. That point is known as the center of pressure (CP).

image007Flow Simulation plot showing the torque values on a rocket of known CP. (Image courtesy of Copenhagen Suborbitals.)

Conclusions                                                                                                                                             

So there you have it. Thanks to CAD (and crowdfunding), you don’t need the budget of NASA in order to design, build and test rockets. But don’t take my word for it…there are many videos of Copenhagen Suborbitals’ test flights (and explosions) on the Web.

For example, the video below shows the Sapphire mission, which was a rocket launched by Copenhagen Suborbitals in order to demonstrate the guidance systems that are to be used in future projects.

The video below shows the HEAT-2X static test bursting into flames.

On a personal level, the most impressive thing to me as an engineer is not how these guys have managed to design, build and test a rocket of this scale on such a small budget, but how they have managed to pull together these resources for a sea-based launch system. Add to that feat the fact that Copenhagen Suborbitals has managed to get the cooperation of air traffic control and various maritime services, and you can see that the whole project is a pretty awesome feat, from an operational and project management perspective.

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