The commissioning of a CubeSat by the Dutch Air Force was announced last November. According to TU Delft researchers, the Air Force is testing the waters for an independent presence in space.
News reports last month mentioned a ‘Dutch spy satellite’ Brik2 to be built over the next two years by TU Delft, NLR, and Isis. In fact, the CubeSat will be a testing platform for space technology for the Dutch Air Force. “We want to know if small satellites can be relevant for military purposes,” said Bernard Buijs, a major in the Dutch Air Force, over the telephone. “Society relies heavily on space infrastructure, and the National Defence should have a presence there.”
The commissioning of Brik2 was the outcome of a six-month feasibility study by three TU Delft researchers (Dr Alessandra Menicucci, Dr Stefano Speretta, and Trevor Watts), which started almost two years ago. The project has a €2.5 million budget, including the launch.
If all goes well, the Ministry of Defence intends to increase the number of satellites and thus strengthen its presence in space, possibly in collaboration with other countries. About 24 satellites are needed to provide continuous cover, so there is room for expansion.
The Air Force is interested in the CubeSat platform because of its short production cycle and the relatively low production cost of these small satellites (the size of two cartons of milk). The launch, however, is still a bit of a concern, since the major providers of launches are Russia, India, and China, arguably not the best countries to partner for military missions
Brik2’s payload includes: (1) a military radio frequency receiver, details not given; (2) a UHF communication system, and (3) a Langmuir probe system to measure the electron density in the ionosphere.
At 600 km altitude, one orbit takes about 90 minutes. An observer on Earth will see three subsequent passes of the satellite (low on the eastern horizon, right overhead and low on the western horizon), to be repeated half a day later. The ionosphere stretches from 50 to 1,000 kilometres of altitude, so Brik2 will be right in the middle of it.
Ionospheric activity is noticeable in the wildly fluctuating GPS signal strengths in the tropics. They vary over time, and from one location to another. Clouds of plasma, with variable density and in several layers, act like metal sheets, shielding GPS receivers from the transmitters in the sky.
CubeSat with Langmuir probes. (Illustration: QB50 project)Dr Alessandra Menicucci (Faculty of Aerospace Engineering) says the Brik2 will be equipped with hardware developed by the University of Oslo and tested in the QB50 CubeSat mission. The Langmuir probe measures the electron density by recording the space current between antennas driven by a potential difference of only a few volts.
At the same time, Brik2 will measure GPS signal strength. Researchers expect that the correlation between ionospheric activity and signal attenuation may be used to improve the physical models and the ‘space weather reports’ based on them.
Another study examines radio communication (UHF) with the satellite. At a speed of over 7 km/s, the Doppler effect significantly changes the radio frequency. Communication equipment has to compensate for that effect. The unit will also contain a store & forward module which temporarily stores information and relays it once communication with a ground station has been established. All this is new terrain for the Air Force research group, explained Buijs.
The launch is expected by the middle of 2019,
- 14-12-2017: Article has been revised and extended
Do you have a question or comment about this article?
j.w.wassink@tudelft.nl
Comments are closed.