IMPACT-SAFE TANK PRESSURE LEVEL – EXPRO PLUS
6, July 2018

ESA Open Invitation to Tender AO9358
Open Date: 04/07/2018
Closing Date: 29/08/2018 13:00:00

Status: ISSUED
Reference Nr.: 18.133.02
Prog. Ref.: Technology Developme
Budget Ref.: E/0901-01 – Technology Developme
Special Prov.: BE+DK+FR+DE+IT+NL+ES+SE+CH+GB+IE+AT+NO+FI+PT+GR+LU+CZ+RO+PL+EE+HU
Tender Type: C
Price Range: 200-500 KEURO
Products: Satellites & Probes / Structures / Struct. Eng. SW / SW for Structure design, analysis, simulation, etc. / Satellites & Probes / Structures / Structures – BB / Propellant tanks
Techology Domains: Structures / Meteoroid and Debris Shield Design and Analysis / Tools and Methodologies for Design and Verification of Meteoroid & Debris Shields / Space Debris / Debris Mitigation, Debris Environment Remediation and Protection / Protection against Debris and Meteoroids
Establishment: ESTEC
Directorate: Directorate of Tech, Eng. & Quality
Department: Mechanical Engineering Department
Division: Structure and Mechanisms Division
Contract Officer: van Hilten, Linda
Industrial Policy Measure: C2 – Activities in open competition, significant partecipat…
Last Update Date: 04/07/2018
Update Reason: Tender issue

The new ESA/ADMIN/IPOL(2014)2 makes applicable the ISO 24113 which states that during the disposal phase, a spacecraft or launch vehicle orbital stage shall permanently deplete or make safe all remaining on-board sources of stored energy in a controlled sequence.All projects have to show compliance to this requirement and this shall be preferably achieved by venting (as far as allowed by thetechnologies available nowadays) and if this is not feasible performing depressurization at least down to a level such that no bursts can occur due over-pressure or over-temperature or HVI (ESSB-HB-U-002, issue 1, 19 February 2015).The physical phenomena happening inside a Tank impacted by a particle at hyper velocity needs to be understood. The debris environment is normally calculated via MASTER 2009, where, for a certain orbit, it is possible to predict the rate and velocitydistribution of debris particle with a diameter included in a user-defined range. Depending on the stress state of the tank, on the location of the tank hit by an HVI debris (or the secondary debris cloud that may result from impact on other parts of the spacecraft that nominally protect the tank), on the content (and kind) of propellant and on the dimension of the impacting particle and its velocity, a methodology shall be developed todetermine the probability of explosions. This effect is particularlyimportant in LEO (e.g. at 800 km an exposed object with the size of a propulsion tank has about 10-3 probability over 25 years of being hit by a 1 cm diameter particle at an average speed of 14km/s). In GEO the number of debris and the energy of the impacts is significantly lower. A target probability shall be proposed in order to define the level of safe pressure inside the tanks. In order to do this, reference case studies shall be defined and justified.Previous ESA investigations have shown that an explosion is possible even when small quantities of propellant are still left inside the tank. Furthermore aging and thermal cycling effects must be taken into account. The phenomena shall be predicted via the use of hyper velocity impact simulations, capturing interaction the transient structural and fluid response to the impact and the fluid-structure interaction and shielding effects. The analyses methodologies shall be validated by worse case condition tests.The topic is a rather complex one, and recommendations for further testing or further development of analytical tools are expected. It is expected that the outcome of this activity will be useful also for the assessment of probability of accidental breakup during the nominal life of LEO spacecraft.Procurement Policy: C(2) = A relevant participation (in terms of quality and quantity) of non-primes (incl. SMEs) is required. For additional information please go to EMITS news “Industrial Policy measures for non-primes, SMEs and RD entities in ESA programmes”.

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