Emergency Trajectories for the Crew Transfer Vehicle

Paper number

IAC-06-D2.3.01

Author

Mr. Jesus Gil-Fernandez, GMV S.A., Spain

Coauthor

Mrs. Mariella Graziano, GMV S.A., Spain

Coauthor

Mr. Bernd Bischof, EADS Astrium, Germany

Coauthor

Mr. Juergen Starke, EADS Astrium, Germany

Year

2006

Abstract

ATV-evolution was an ESA study leaded by EADS ST that investigated potential uses of modified ATV such as the transportation of a crew to the ISS. This paper focuses on the emergency trajectories of the Crew Transfer Vehicle (CTV) after the Launch Escape System (LES) has been jettisoned, i.e. the failure takes place when in exo-atmospheric flight. The CTV mainly consist of a modified ATV with the control authority and a capsule for the re-entry of the crew.

The CTV emergency trajectories must assure the safe re-entry of the crew while avoiding any risk to population, i.e. descent on land is forbidden safe in specially prepared areas. Possible and suitable strategies are the following,

o Abort to Atlantic, where the main objective is to control the splash-down point location in order to reduce the number of rescue teams,
o Abort to orbit, where a stable enough emergency orbit is reached avoiding the landing on continental Europe,
o Abort to Woomera (Australia), where a landing in the Woomera spaceport is achieved before one revolution, i.e. no injection into orbit.

Although not the main purpose of the study, the launch \& ascent trajectory of a launcher similar to Ariane5 EPS-V (2 burns) is optimized (maximum payload into desired orbit) to obtain the initial conditions at failure. Other sub-optimal launch \& ascent trajectories are computed to fulfil additional constraints of the CTV trajectories not applicable in conventional Ariane5 launches.

The emergency trajectories computation will imply the optimization of the CTV propelled trajectory, the exo-atmospheric flight after the failure of the Ariane5 EPC (Etage Principal Cryotechnique); along with the capsule re-entry and descent trajectory, in this case different lift-to-drag ratios are analysed corresponding to different capsule types (bi-conic and Viking-type). In the abort to Atlantic case, the minimum and maximum downrange trajectories are computed, together with the pure ballistic and mixed strategies giving the downrange capability of the propelled exo-atmospheric flight and the capsule descent. In the case of the peak load factor, the attitude control strategy plays an important role that is analysed.

The required CTV thrust level, capsule control strategy and launcher ascent trajectory constraints will be derived in order to assure the overlapping of the strategies, the avoidance of landing on Europe and the safety of the crew during the re-entry.

Abstract document

IAC-06-D2.3.01.pdf

Manuscript document

IAC-06-D2.3.01.pdf (🔒 authorized access only).

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