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The International Archives of the Photogrammetry. Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
In addition, QinetiQ has developed a mobile ground station, 
consisting of a 2.7m receiving dish towed by a Land Rover, 
which has demonstrated the ability to downlink near-real time 
TopSat imagery directly to end users. 
1.3 New Approaches 
Missions such as Topsat and Proba are made possible by the 
pragmatic application of key technologies and new approaches 
to the programmatic and system design. A flexible response to 
the customers needs is the hallmark of the QinetiQ-Verhaert 
approach. Simplified programmatic structures, integrated teams, 
on-board automation and new technologies all have their part to 
play in reducing costs. The mission must be viewed as a 
complete system and the component segments design to 
minimise through life costs by matching risk with customer 
expectation and technical solutions. 
2. SMALL MISSION SOLUTIONS 
Small satellites can play an important role for earth observation 
applications, which is proven in the meantime by the successful 
PROBA / Topsat missions. 
To date, the application field stays limited to imagery with up 
to a few meters of ground resolution and a few spectral bands in 
the visible and near-infrared spectrum. Clearly, this is driven by 
the resources and performances available on small platforms 
but thanks to the evolving technologies on payloads and 
platform side a lot of other applications come within our reach.. 
A nice example of this capability improvement is demonstrated 
on PROBA 2; compared to PROBA 1 the payload carrying 
capability is increased from 30% to 40%. A major contribution 
in this improvement is coming from our on-board computer 
based on the Léon chip, 3,3 V and SMD component technology. 
Small missions will never be suited, and are not intended, to 
replace the full capability of large systems, but they will be a 
very interesting complement to it. Small missions may be able 
to provide solutions for 80% of the requirements at only 20 % 
of the cost and as such are very interesting as gapfiller, 
precursor or stand-alone solution. 
Over the years, several concepts and ideas wore worked out to 
show the potential of our PROBA platform for emerging 
applications. Indeed, we can talk about the Proba Spacecraft 
Family of which some key potential is highlighted hereafter. 
2.1 Small Satellites for earth observation 
Future important application fields for small missions lie in the 
area of high-resolution images (security - dual use), more 
spectral bands (vegetation - precision farming) and SAR 
imagery (overnight visibility). 
Clearly, this type of instruments requires more power, more 
volume, more data storage & downlink capability, but smart 
solutions and optimisations allow overcoming of the challenges. 
Several studies were carried out to demonstrate the feasibility 
of following missions based on a PROBA platform: 
High Resolution 
The major challenge for this type of missions is the thermal 
stability on the instrument and platform stability required to 
provide sharp images. 
Availability of high performance gyro’s in combination with a 
performant attitude control system on the satellite, allow to 
build PROBA satellites which can provide ground resolutions 
up to 1 meter (e.g. ARGUS phase A study for ESA). 
Multispectral / Hyperspectral / Lidar 
Access to QinetiQ’s specialised hollow wave-guide 
technologies offer the possibility of smaller sensors, which will 
deliver comparable optical performance on small satellites. 
New mission solutions including Lidar and microwave sounder 
systems will become possible with QinetiQ’s Gallium Nitride 
technologies. These offer the possibility of even smaller and 
more electrically efficient sub-systems. Currently, we are 
working on the phase B for an ESA multispectral mission, 
called PROBA V. 
Multi- and hyper spectral instruments work typical at lower 
resolutions but generate huge amounts of data. Here solutions 
can be worked out in several areas, starting with data capturing 
optimisation (to reduce the capture of un-usable data), data 
compression and storage and high power downlink capacity. 
Radar 
Radar missions on a small satellite are a challenge since we 
have to deal with relatively large antenna systems and large 
peak power requirements. 
Studies are ongoing to fly optimised systems with shorter 
lifetime (less redundancy) on a small platform, and 
investigation continues in to low altitude missions. 
Formation Flying 
Formation flying with small platforms is demonstrating the 
usefulness for pré-cursor missions. Before entering in a very 
ambitious science mission, critical technologies can be 
developed and demonstrated in orbit in a fast and cost-effective 
way. 
Currently, we are preparing for the phase B for the ESA 
PROBA 3 formation-flying mission. 
Microgravity platform 
Verhaert Space performed for ESA a study (Wakeshield type of 
platform for high-quality microgravity research). In this concept, 
we use a PROBA based ffee-flyer which operates in the vicinity 
of the ISS. The challenges added to the platform are related to 
docking & payload exchange and the triple redundancy required 
for safety related aspects. 
Small Satellites for Interplanetary mission 
NEO missions such as SIMONE, as well as ESMO and Don 
Quijote are predicated on the use of electronic propulsion (EP) 
to access regions of the inner solar system (beyond Earths 
gravitational influence). 
In addition to the existing LEO applications of small spacecraft, 
new missions are being developed to utilise small satellites in