TU Delft’s nano-satellite Delfi-C3 is scheduled to be launched on June 30, 2007, from a site in India onboard the Polar Satellite Launch Vehicle (PSLV).
One of the most multinational teams ever assembled at TU Delft is currently working on the Delfi-C3 project, which should place TU Delft on the cutting edge of the current space race aimed at miniaturizing space vehicles.
Nano-satellites are the current hype in space technology. The ultra-hip ‘nano’ tag refers to a satellite weighing only a few kilograms and of very modest dimensions, as opposed to the hundreds or thousands of kilograms of conventional satellites. This lightness allows nano-satellites to be launched ‘piggy-back’, hitchhiking on larger satellites or in large batches, and making the launch relatively inexpensive and the system less vulnerable to the loss of a single satellite.
The Delfi-C3 project is being conducted in close collaboration between the TU’s Faculty of Aerospace Engineering, and Electrical Engineering, Mathematics and Computer Science Faculty, and is being coordinated by Rob Hamann and Chris Verhoeven of the respective faculties.
Delfi-C3 utilizes the space-proven CubeSat concept, which provides commercial off-the-shelf components for the structure that will accommodate the payload in space: ‘just’ design the payload to the prescribed dimensions, bolt it into the cube you bought, and voila, you’re ready to launch.
The reality is of course not so simple. The Delfi-C3 team is putting not one but three different payloads into orbit, using a 10x10x30 cm ‘shell’, provided by Pumpkin, Inc. The payloads and subsystems are being designed simultaneously, in what is called ‘concurrent design’, a challenge that Abe Bonnema, Delfi-C3 project manager at the Faculty of Aerospace Engineering, compares to “digging the Channel Tunnel from France and the UK and meeting exactly in the middle.”
According to Bonnema, the greatest challenge is getting the computer systems and power systems to work reliably together. He says he knows of other similar projects for which very good subsystems were designed, only for the sub-teams to find out later during their first system integration meeting that no single plug fit with other components. Perhaps it’s for such unexpected situations that Bonnema keeps a heavy wrench on his desk.
The payloads the Delfi-C3 satellite will carry include two analog, fully autonomous, wireless sun sensors (located at opposite sides of the satellite) designed by TNO. The experiment will concentrate on demonstrating the feasibility of the wireless link and the operation of the sun sensor under a variable power supply. Also onboard will be four sets of a new type of Thin Film Solar Cells developed by Dutch Space, and an advanced communication package designed at the Electrical Engineering Faculty.
The data will be transmitted via a distributed ground station network that relies on the resources of radio amateurs worldwide and will available to everyone. The team auctioned off the opportunity for a radio amateur to fly his call-sign on Delfi-C3, with Mr. Ken Eaton chosen to fly his call-sign, GW1FKY. .
Two French students from Toulouse University, Mathieu Causse and Camille Hue, are in Delft on three-month internships to work on the project. Their job is to develop the altitude algorithms necessary to calibrate the measurements. Hue: “What we want to do is define the position of the satellite relative to the sun, using current measurements on the solar panels’ cells. This will give us the opportunity to calculate the angle of incidence of each panel to the sun and determine the response and functionality of the Thin Solar Cell payload.”
Although such projects are less common at their home university in France, Causse says working as part of a team is “not a problem”. The French interns are however slightly frustrated by their deficiency in English, compared to the rest of the team. “At our home university, we get two to three hours of English per week, which is much too little. Here, everyone speaks English fluently,” Camille says. English is of course the official language of the Delfi-C3 project team, whose members come from ten different countries.
‘Vomit-Comet’
To date, a number of CubeSat’s have been launched elsewhere, and Bonnema says that some have performed very well. The largest trouble source has proven to be the new lithium-ion batteries, a problem that the Delfi-C3 satellite handles quite elegantly: the satellite has no batteries at all. The solar panels and sun-sensor (which has its own small solar cell) are, after all, only expected to work in sunlight.
Delfi-C3 is currently scheduled for launch on 30 June 2007, and will rise 630 kilometers in a path over the poles. However, the Delfi-C3 team has purchased 2 CubeSat structures – a flight model and flight spare . just in case. And this is wise precaution, considering the recent crash of a Dnepr launch vehicle that was supposed to carry a fleet of 14 CubeSat’s into orbit.
Even if the first launch goes well, the flight spare Delfi-C3 might be launched anyway, but modified to fit improved versions of some of the subsystems and payloads that feature the new technology that won’t be available in time for the first launch.
Many of the subsystems currently being produced or developed still have a long way to go to completion, as they all must be space-verified and tested. So, for example, the antenna deployment system, pre-tested in Delft aboard the Aerospace Engineering Faculty’s Cessna Citation airplane, will undergo extensive testing onboard the notorious ‘Vomit-Comet’, the nickname for the European Space Agency’s Airbus A300 that is used to perform zero gravity experiments.
Ana Frutos Pastor, from Spain, has been working on the Delfi-C3’s communication payload for several months, and describes the deployment sequence: “The antenna is special, because it’s made of tape spring, the same type that’s used for household measuring tapes. The antenna is stowed in a rolled-up state inside a box. There’s a lid, which keeps the antenna in place, and a piece of Dyneema wire attached to the lid, which also wraps around an
electrical resistor. To deploy the antenna, the resistor is heated, the Dyneema melts, loosening the lid, and the antenna functions as a spring and deploys.”
Another of the many international participants in the project, Marco Gratziosi, from Italy, recently arrived in Delft to begin his graduation thesis based on this project. Gratziosi is responsible for the development and assembly, integration and verification (AIV) of Delfi-C3’s mechanical, structural and thermal subsystems.
Although the Delft-C3 project is well underway and has set its course for completion by the June 30, 2007 launch date, numerous other internship and graduate places are still available within the Delfi-C3 team.
For more information about joining the Delfi-C3 team, contact Abe Bonnema, Aerospace Engineering Faculty project manager: a.r.bonnema@tudelft.nl
Delfi-C3: still on the drawing board. (Illustrations: Courtesy of TU Delft)
Nano-satellites are the current hype in space technology. The ultra-hip ‘nano’ tag refers to a satellite weighing only a few kilograms and of very modest dimensions, as opposed to the hundreds or thousands of kilograms of conventional satellites. This lightness allows nano-satellites to be launched ‘piggy-back’, hitchhiking on larger satellites or in large batches, and making the launch relatively inexpensive and the system less vulnerable to the loss of a single satellite.
The Delfi-C3 project is being conducted in close collaboration between the TU’s Faculty of Aerospace Engineering, and Electrical Engineering, Mathematics and Computer Science Faculty, and is being coordinated by Rob Hamann and Chris Verhoeven of the respective faculties.
Delfi-C3 utilizes the space-proven CubeSat concept, which provides commercial off-the-shelf components for the structure that will accommodate the payload in space: ‘just’ design the payload to the prescribed dimensions, bolt it into the cube you bought, and voila, you’re ready to launch.
The reality is of course not so simple. The Delfi-C3 team is putting not one but three different payloads into orbit, using a 10x10x30 cm ‘shell’, provided by Pumpkin, Inc. The payloads and subsystems are being designed simultaneously, in what is called ‘concurrent design’, a challenge that Abe Bonnema, Delfi-C3 project manager at the Faculty of Aerospace Engineering, compares to “digging the Channel Tunnel from France and the UK and meeting exactly in the middle.”
According to Bonnema, the greatest challenge is getting the computer systems and power systems to work reliably together. He says he knows of other similar projects for which very good subsystems were designed, only for the sub-teams to find out later during their first system integration meeting that no single plug fit with other components. Perhaps it’s for such unexpected situations that Bonnema keeps a heavy wrench on his desk.
The payloads the Delfi-C3 satellite will carry include two analog, fully autonomous, wireless sun sensors (located at opposite sides of the satellite) designed by TNO. The experiment will concentrate on demonstrating the feasibility of the wireless link and the operation of the sun sensor under a variable power supply. Also onboard will be four sets of a new type of Thin Film Solar Cells developed by Dutch Space, and an advanced communication package designed at the Electrical Engineering Faculty.
The data will be transmitted via a distributed ground station network that relies on the resources of radio amateurs worldwide and will available to everyone. The team auctioned off the opportunity for a radio amateur to fly his call-sign on Delfi-C3, with Mr. Ken Eaton chosen to fly his call-sign, GW1FKY. .
Two French students from Toulouse University, Mathieu Causse and Camille Hue, are in Delft on three-month internships to work on the project. Their job is to develop the altitude algorithms necessary to calibrate the measurements. Hue: “What we want to do is define the position of the satellite relative to the sun, using current measurements on the solar panels’ cells. This will give us the opportunity to calculate the angle of incidence of each panel to the sun and determine the response and functionality of the Thin Solar Cell payload.”
Although such projects are less common at their home university in France, Causse says working as part of a team is “not a problem”. The French interns are however slightly frustrated by their deficiency in English, compared to the rest of the team. “At our home university, we get two to three hours of English per week, which is much too little. Here, everyone speaks English fluently,” Camille says. English is of course the official language of the Delfi-C3 project team, whose members come from ten different countries.
‘Vomit-Comet’
To date, a number of CubeSat’s have been launched elsewhere, and Bonnema says that some have performed very well. The largest trouble source has proven to be the new lithium-ion batteries, a problem that the Delfi-C3 satellite handles quite elegantly: the satellite has no batteries at all. The solar panels and sun-sensor (which has its own small solar cell) are, after all, only expected to work in sunlight.
Delfi-C3 is currently scheduled for launch on 30 June 2007, and will rise 630 kilometers in a path over the poles. However, the Delfi-C3 team has purchased 2 CubeSat structures – a flight model and flight spare . just in case. And this is wise precaution, considering the recent crash of a Dnepr launch vehicle that was supposed to carry a fleet of 14 CubeSat’s into orbit.
Even if the first launch goes well, the flight spare Delfi-C3 might be launched anyway, but modified to fit improved versions of some of the subsystems and payloads that feature the new technology that won’t be available in time for the first launch.
Many of the subsystems currently being produced or developed still have a long way to go to completion, as they all must be space-verified and tested. So, for example, the antenna deployment system, pre-tested in Delft aboard the Aerospace Engineering Faculty’s Cessna Citation airplane, will undergo extensive testing onboard the notorious ‘Vomit-Comet’, the nickname for the European Space Agency’s Airbus A300 that is used to perform zero gravity experiments.
Ana Frutos Pastor, from Spain, has been working on the Delfi-C3’s communication payload for several months, and describes the deployment sequence: “The antenna is special, because it’s made of tape spring, the same type that’s used for household measuring tapes. The antenna is stowed in a rolled-up state inside a box. There’s a lid, which keeps the antenna in place, and a piece of Dyneema wire attached to the lid, which also wraps around an
electrical resistor. To deploy the antenna, the resistor is heated, the Dyneema melts, loosening the lid, and the antenna functions as a spring and deploys.”
Another of the many international participants in the project, Marco Gratziosi, from Italy, recently arrived in Delft to begin his graduation thesis based on this project. Gratziosi is responsible for the development and assembly, integration and verification (AIV) of Delfi-C3’s mechanical, structural and thermal subsystems.
Although the Delft-C3 project is well underway and has set its course for completion by the June 30, 2007 launch date, numerous other internship and graduate places are still available within the Delfi-C3 team.
For more information about joining the Delfi-C3 team, contact Abe Bonnema, Aerospace Engineering Faculty project manager: a.r.bonnema@tudelft.nl
Delfi-C3: still on the drawing board. (Illustrations: Courtesy of TU Delft)
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