PROBA SPACECRAFT FAMILY 
SMALL MISSION SOLUTIONS FOR EMERGING APPLICATIONS 
Jo Bermyn 
Verhaert Space, Hogenakkerhoekstraat 9, B-9150 Kruibeke, Belgium - Jo.bermyn@verhaertspace.com 
WG 1/6 - Small Satellites 
KEY WORDS: Small satellites, Earth observation 
ABSTRACT: 
Small Satellites are now being developed by many organisations. These are now a mature technology and have demonstrated their 
potential as a product with complementary performances to more conventional mission solutions. Recent successes with the PROBA 
1 (more than 6 years operating in orbit) and the UK’s Topsat spacecraft show the potential to use these platforms in a flexible and 
low-cost way for Earth Observation missions. ESA’s Earth Observation Directorate uses PROBA 1 on a daily basis in support of 
research related to vegetation, disaster monitoring, land use, volcano observations, etc. With continued advances in technology, new 
areas in Earth observation are being explored and applications like high resolution-, hyper spectral- and small SAR radar missions 
become feasible with a PROBA scale platform and its derivatives. As small satellite missions become more ambitious, so the space 
industry is adapting to the challenge of creating organisations which can deliver the advantages of small satellite technology while 
retaining compatibility with international data standards and operating practices. The merging of Verhaert Space and QinetiQ’s 
Space Division is a first step in the creation of a solid mid-tier player dedicated to small mission solutions, combining 
complementary skills in mission design, system integration and key areas of technology development to offer end-to-end solutions to 
customers worldwide. This paper will outline high-performance solutions for future Earth observation missions, highlighting the role 
that cutting-edge technologies have to delivering unique capability to meet customer needs. 
1. SMALL MISSIONS HERITAGE 
1.1 Proba 1 / Proba 2 
Mid nineties, ESA initiated the idea for building a small 
satellite for technology demonstration purposes, called PROBA 
(Project for On-Board Autonomy). With the financial support 
from the Belgian Science Policy Office to ESA’s General 
Support Technology Programme (GSTP), Verhaert Space 
finally could win the phase C/D contract that started in 
February 1998. 
PROBA 1 is the first Belgian small satellite and is developed by 
Verhaert Space as prime contractor. The satellite, only 
weighing 94 kg with dimensions 80 x 60 x 60 cm, was realised 
in about 3 years. The strong features of the PROBA platform lie 
in the field of autonomous operation (low operational cost), its 
simplicity in operation, its performant attitude control system 
and its strong Léon based computing capability. PROBA’s 3- 
axis attitude control system provides fine-pointing capabilities, 
resulting in precise snapshot images (e.g. HRC instrument - 4m 
pan images) and has agility to execute demanding mapping and 
push-broom scanning scenarios (e.g. CHRIS instrument -18m 
multispectral images). 
Although designed for a lifetime of only 2 years, PROBA 1 is 
now functioning in-orbit for more then 6 years and providing 
earth observation images through ESA to the science 
community on a daily basis. 
In the meantime, its successor PROBA 2 carrying sun 
observation instruments is under final integration at Verhaert 
Space and is planned for launch early 2009. 
The PROBA platforms are operated through a small ground 
station (2,4 m dish) located at the ESA Redu site in the Belgian 
Ardennes. 
Figure 1. PROBA 1 on PSLV launcher (ISRO./Antrix) 
Figure 2. .PROBA/HRC Image of pyramids of Gizeh (ESA)