planet transiting a star
July 15, 2014

New Exoplanet Mission Takes Another Step Towards Launch

John P. Millis, Ph.D. for - Your Universe Online

Space missions generally fall into three different categories: small, medium, and large. Dull naming conventions aside, the various mission types really tell the story of the scale of the projects. But make no mistake; even “small” missions can have a big impact.

Recently, the European Space Agency (ESA) has been focusing more on medium and large-scale projects, but that is all changing. The forthcoming CHaracterising ExOPlanet Satellite (CHEOPS) is the first in what the agency hopes is a series of small missions.

These new small missions are relatively low cost, easy to launch, and most critically have a short turnaround time. CHEOPS has passed the first hurdle on the way to its scheduled launch in 2017, having gone from Selection to Implementation in a scant 18 months.

Selected in October 2012 from among 26 competing proposals for the first of the ESA’s small mission programs and limited to a cost of 50 million euros, the project is being developed by a consortium of 11 European union countries, and will be led by the Swiss Space Office (SSO), a division of the Swiss State Secretariat for Education, Research and Innovation (SERI), and the University of Bern, Switzerland.

According to Nicola Rando, ESA Definition Phase Manager for CHEOPS, "The cost and schedule constraints associated with a small mission in the Science Program mean that all platform components and systems have to be ‘off-the-shelf’ and qualified for use in space. The only new development is the scientific instrument, which has to fulfill specific requirements but even that relies on available technologies."

Of course, simply because the satellite will utilize only off-the-shelf systems, the implication is not that the mission is merely a rehash of previous work, or that nothing novel will be brought to the science. In fact, even the implementation of the mission is novel. "CHEOPS demonstrates an interesting adaptation capability of ESA and its Member States in implementing missions," says Frédéric Safa, ESA Head of Future Missions Office, where CHEOPS is being implemented. "So far, its fast track schedule has been met thanks to an efficient collaboration between industry, the instrument consortium, and the ESA teams."

Much of the mission’s early success can be traced to the ease at which the individual members and industry partners are able to communicate and exchange ideas. While such large scale projects have prior been bogged down by government bureaucracy, especially with the individual demands placed on each member, a new paradigm is being enacted that could change the way small missions are organized and run in the future. "The Member States’ relative contribution to the mission is significantly larger than for medium and large missions, and a tailored industrial procurement approach had to be developed for meeting small mission programmatic targets, while preserving a science-driven approach for the mission. The good relationship between the ESA and the Swiss teams enabled fast decisions when needed and definitely played an important role," says Safa.

But the CHEOPS mission is more than simply an exercise in project implementation; it will pave the way for future studies of worlds beyond our solar system. The last decade has seen enormous advancement in the field of exoplanetary astronomy. Before, few planets were confirmed outside of our own solar system, now hundreds have been measured, with thousands of more candidates simply waiting to be confirmed. The accumulated data currently outpaces the number of astronomers and instruments available to conduct the follow-up studies.

It is this rapid accumulation of data that has also opened the door for instruments like CHEOPS to come online. It is not enough to simply know that planets exist around a star; astronomers want to know, with high precision, the characteristics of these systems. However, current observatories are not able to properly characterize shallow transits, leaving a hole in the exoplanetary data set.

"CHEOPS is a unique high-precision photometric observatory that can point nearly anywhere in the sky. It will be used to search for transits on bright stars already known to host planets," says Willy Benz from the University of Bern, Switzerland, and principle investigator on the CHEOPS mission. "By knowing where to look and at what time, CHEOPS is the most efficient instrument to detect shallow transits. It will significantly increase the sample of exoplanets for which we know both mass and radius, providing new insights and constraints on formation models. It will also provide the best targets for subsequent spectroscopic studies by the next generation of ground- and space-based instruments."


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