PROBA-IP: An ESA Technology Demonstration Mission Targeted to Apophis
Cano, Juan L.1; Peñín, L.F.1; Cornara, S.1; Santandrea, S.2; Marcos, F.3; López, A.3; Jentsch, C.4; Bernhardsdotter, E.5; Taylor, M.6; Page, O.7
1DEIMOS Space S.L.; 2ESA / ESTEC; 3EADS CASA Espacio; 4EADS Astrium Satellites; 5SSC; 6SSTL; 7SciSys
The utilisation of small and low cost platforms developed and launched in a short timeframe for the in-flight validation of new space technologies has been successfully demonstrated within ESAτs PROBA Programme for Earth bound missions.
In such context a NEO has been envisaged as PROBA-InterPlanetary (PROBA-IP) target. Close-up reconnaissance of NEOs based on relatively inexpensive small satellites would in fact represent a valuable technology validation experience, beneficial to the success of future major scientific and exploration missions. This type of missions could also provide elements for the assessment of how well the threat posed by NEOs to the Earth in the future can be defined and counteracted, and thus pave the way to more complex systems executing specific mitigation strategies. This activity is then targeted to the preliminary design of this kind of missions using a micro/mini-satellite approach.
The main objective of the PROBA-IP mission is the in-orbit validation of autonomous onboard guidance, navigation and control technologies for interplanetary cruise and for the targeting of other celestial bodies, primarily using onboard optical systems technologies. Such technologies will foster the reduction in operation costs of Solar Systems exploration missions and enable characterisation of NEOs. PROBA-IP will also demonstrate micro/mini-spacecrafts capabilities into the interplanetary missions' domain. Current target for the mission is Apophis.
The PROBA-IP mission will implement and validate the following technologies and functionalities:
1) Onboard GNC technology elements for autonomous spacecraft navigation, guidance and control for interplanetary cruise primarily using onboard optical systems,
2) Autonomous targeting of, and rendezvous with, a NEO,
3) Autonomous achievement and maintenance of a safe closed orbit around the target object,
4) Use of (power limited) SEP throughout the entire mission and in all mission phases after Earth orbit escape,
5) Autonomous onboard resources management and FDIR, including autonomous SEP management,
6) Application of novel ground support and operations concepts, whenever necessary to support the autonomy level described above,
7) Demonstration of methodology, tools and infrastructure required for the development and implementation of an interplanetary mission including ground validation of the missions autonomous characteristics.
Additionally to the previous objectives some scientific objectives are considered as potential experiments in order to determine target's (Apophis) properties as shape, rotation state, gravity field, surface properties and accurate orbit determination by means of a Radio Tracking Experiment (RTE). If resources are available the RTE should allow a precise determination of the asteroid orbit enough to ascertain whether Apophis will actually represent a threat to Earth.
The current study represents a preliminary mission and system study promoted by ESA and performed by a Consortium lead by DEIMOS Space and supported by EADS CASA Espacio, Astrium GmbH, SSC, SSTL and Scisys. Current design foresees a three-year mission launched with VEGA in 2015. Escape from Earth is achieved by means of an upper stage. 2.5 years would be devoted to the low-thrust transfer to the asteroid and six months for in-orbit operations. RTE would expand for three months in a photogravitational stable orbit. Current estimate of spacecraft wet mass is in the 350 kg range.