Rationale:

Balloons have been used for decades to conduct scientific studies. While the basics of ballooning have not changed, balloon capabilities have increased and their dependability has improved greatly. Several reasons justify the use of balloons, among these the principal are:

1. Balloons can be launched from locations worldwide to suport scientific needs. Several launch bases are located in Europe (Italy - Trapani, France and Spain) and in the United States and in the Artic and Antartic Regions.
2. Balloons can be readied for flight in as little as six months. This short time scheduling gives the possibility for new concepts to be developed, tested, evaluated, redesigned and retested to optimize systems.
3. Balloons are significantly less expensive and highly risk tolerant for conducting science investigations respect space satellites.
4. Balloons provide a stable platform for longer flight durations and so for increasing scientific data collection.
5. Balloons offer the possibility to develop and test space mission prototypes.

Another significant meaning of Ballooning is the fact that usually leads to the opening of new fields of study and therefore gives the possibility to test untried, high risk technologies with relatively low costs infrastructures respect space missions.
Furthermore balloon program allows comparison based on real flight data rather than simulations.

Developing balloon payloads at universities addresses the workforce development issue; and for the University of Padova this has to be a main objective; in fact we do not have to forget that:

• The primary function of a university is student education and training
• University students are in resident full time, so they can participate in a balloon project without impacting their degree program
• Balloon payload development timescales are short enough so students can gain experience through ALL project phases

Our group has been involved in two main projects:

• HASI: for the Huygens Mission and developing and  testing instruments for new missions

SORA: for the MRO Mission

Several stratospheric balloon flight experiment campaign where conducted in the period 2000-2003, in collaboration with the Italian Space Agency (ASI), to simulate the Huygens probe descent on Titan. Data analysis has performed until 2005.
CISAS started to develop the activities on balloon flights experiments to verify sensors for planetary atmosphere entry probes effective performance in conditions similar to those of the real mission descent. Earth’s atmosphere reproduces satisfactorily the atmosphere structure of Titan and Mars.
A mock up of the Huygens probe carrying onboard HASI instrument and other Huygens instrumentation was launched with a stratospheric balloon and lifted up to an altitude higher than 32 kilometres. After balloon separation, the probe started to descend dragged by the parachute till the impact on ground. The measurements carried out during all the ascending and descending phases are transmitted in real time to ground by telemetry to check the system functionality and send telecommands. At the same time data are recorded and stored on board for post-flight processing. After landing the gondola and payload are recovered.

The HASI team at CISAS has been responsible the overall design and manufacturing of the experiment, its assembly, integration and testing.
The activities carried out comprise the mechanical and thermal design of the probe, the design of the power supply subsystem, the architectural design of the data acquisition systems including the development of the flight and ground software.
The sensors onboard are from HASI experiment, Huygens probe and others for housekeeping or scientific investigations for future space missions as the MARS TEMperature sensors, UV sensor of MEX-Beagle2.

• To verify sensor performance and perform a realistic functional test in dynamical and environmental conditions similar to those during the descent in Titan atmosphere.
• To perform electrical measurements less affected by terrestrial electromagnetic environment at ground having onboard dedicated sensors (i.e PWA subsystem).
• To test and verify the Huygens RADAR behaviour and altimeter performance.
• To check HASI operations at instrument level; the complete HASI instrument flew on board the 2003 experiment.
• To study the possible aerodynamic disturbances on pressure and temperature measurements induced by Huygens probe configuration.
• To obtain a real data set to exercise descent trajectory reconstruction.

Moreover the data acquired by the HASI instruments were used to study and characterise the physical properties (density, pressure and temperature vertical profiles, atmospheric conductivity profile and electrical fields and terrestrial magnetic field) of the Earth atmosphere and to investigate electrostatic charging processes of the balloon and gondola surface.

Funding
Program was conducted under a contract with the Italian Space Agency.

During 2008 summer from Svalbard (Norway) using a stratospheric balloon a model of SHARAD Radar (now onboard MRO spacecraft) will be tested in the Arctic. The experiment aims to test in a Martian analogue atmosphere the Radar in order to have a set of reference measurement to be used to eliminate possible ambiguities in Mars data analysis. Moreover the campaign will provide valuable information on ice thickness, sub-ice lakes, layers discontinuity lithological and compositional changes, layer geometries, physical properties. At the moment a 10 days circumnavigation of the Artic pole is foreseen.
The experiment will be carried onboard a gondola that will provide the Scientific team with all the necessary subsystems and information available.
The gondola main subsystems are: the mechanical structure and the thermal control subsystem; the power subsystem, the data handling and management subsystem (together with the telemetry) and the housekeeping subsystem. Data transmission and power are the most demanding; the radar produces a huge amount of data that will be stored on board while, due to the low bit rate of data transmission possible, only housekeeping informations will be sent to ground; on the other hand power consumption is high and batteries have to be recharged.

Since radar and data have to be recovered a secure floating mechanism is under study for saving the system also in case of splashing in the north sea. In the meanwhile a ground support equipment is under designing both for engineering activities and for scientific analysis.

Principal scientific objectives are to provide valuable information on ice thickness, sub-ice lakes, layers discontinuity lithological and compositional changes, layer geometries, physical properties.
Perform a test campaign to operate the radar in Martian Analogue environments  in order to provide a set of reference measurement to be used to eliminate possible ambiguities in Mars data analysis.

Funding

Program was conducted under a contract with the Italian Space Agency.

Lighter-than-atmosphere (LTA) systems provide signi?cant advantages for terrestrial and planetary exploration due to their potential for extended mission duration, long traverse, and extensive surface coverage capabilities. Robotic airships, in particular, are ideal platforms for airborne planetary exploration. Airships have modest power requirements, and combine the extended airborne capability of balloons with the maneuverability of airplanes or helicopters. Their controllability allows precise ?ight path execution for surveying purposes, long-range as well as close-up ground observations, station-keeping for long-term monitoring of high-value science sites, transportation and deployment of scienti?c instruments and in-situ laboratory fa- cilities across vast distances to key science sites, and opportunistic ?ight path re-planning in response to the detection of relevant science sensor signatures. Furthermore, robotic airships provide the ability to conduct extensive surveys over both solid terrain and liquid-covered ar- eas, and to reconnoiter sites that are inaccessible to ground vehicles. Implementation of these capabilities requires achieving a high degree of vehicle autonomy across a broad spectrum of operational scenarios. Airship Research Program is a multidisciplinary collaboration in order to cover the different issues of the architecture, i.e. dynamics and control, aerodynamics, gondola design, navigation, propulsion. CISAS has its on Airship as test-bed for flying instruments and for validate the aerodynamical and propulsion models used in the Airship Flight Simulator developed. The simulator is able to investigate the behaviour of the airship in different environments.