GEOScan Program Background

Iridium Communications Inc. is launching Iridium NEXT, a new-generation of low-Earth orbiting (LEO) polar communication satellites in 2015-2017. Iridium NEXT's 66+ global satellites have each been designed to accommodate a standard payload, which provides a unique capability to host scientific sensors with 24/7 real-time visibility over the entire Earth's surface and atmosphere. Four primary factors make this an unprecedented opportunity for geoscience discovery, while holding the potential to affect a paradigm shift in the way we conduct science from space:

• Truly global coverage provided by the constellation allows us to address open scientific questions never before possible! These grand challenges will likely not be addressed without GEOScan for the next 15-20 years.
• Massively dense space-based measurements enable revolutionary new techniques such as tomographic imaging and provide truly novel datasets for the community to investigate.
• Because Iridium is the world's farthest reaching network, the logistical and cost barrier of transmitting massive amounts of data from 66+ satellites is REMOVED!
• Because we plan to build nearly 70 uniform GEOScan SensorPODs, we can take advantage of the cost savings of scale for science from space instead of the extremely costly "one of a kind" methods of the past.

GEOScan is taking advantage of this opportunity via a grass-roots effort to propose a geoscience facility from space to the National Science Foundation that will benefit a broad cross-section of the scientific community and society in general.

The purpose of this ongoing effort is to advance the GEOScan concept to the next stage of NSF MREFC planning and implementation. First a conceptual design stage, detailed in a feasibility report, will be provided to NSF in August. Ultimately we expect to propose the GEOScan MREFC program to NSF at the conclusion of 2011.

A planning workshop was held to gather ideas, proposals and feedback from the geoscience (Solid Earth, Atmosphere, Ocean, and Geospace) community for the purposes of selecting overarching scientific goals and determining the sensors and measurements needed to accomplish these goals.

Iridium NEXT & GEOScan

Figure 1: Iridium NEXT Schematic including their entire hosted payload bay. Click to Enlarge

Thales Alenia Space (TAS) has been awarded a $2.2B contract by Iridium to build 81 satellites for this next-generation constellation. Space Exploration Technologies (SpaceX) has been contracted as primary launch provider. Iridium has also closed on loans by a consortium of banks to fund the NEXT system development. Coface, France's export credit agency (ECA), has guaranteed 95% of $1.8B credit facility. Thales is expected to select a US company to be the satellite integrator and to manage hosted payload integration.

Iridium has developed a schedule milestone that provides an enhanced support for the hosted payload integration. The initial hosted payload Interface Control Document (ICD) is available. Payloads conforming to the ICD have until Satellite CDR (1Q 2013) to make first launch with delivery happening as late as 6 months prior to each launch. Non-conforming payloads must begin commitment by Satellite PDR (1Q 2012).

NEXT SensorPOD for GEOScan

Figure 2: Iridium NEXT SensorPod Schematic. The GEOScan SensorPod will consist of 1 of these 5.6U boxes shown in the diagram. The SensorPod will have access to both ram and nadir facing directions. Click to Enlarge

The GEOScan program plan uses a single 5.6U SensorPOD slot on each of the 66 NEXT satellites as depicted in Figure 2. The following section describes the proposed plan for the GEOScan SensorPods and resulting GEOScan program.

GEOScan Program Themes

The GEOScan program can be broken down into two highly complementary themes (see Figure 3 for a high level outline of program theme goals): the System Sensor program and the Hosted PI Sensor program. In total we expect two or three System Sensors and one Hosted PI Sensor to be accommodated by each GEOScan SensorPod. The engineering extent of GEOScan involves producing 66+ GEOScan SensorPods, integrating two SS and one PI provided HS together with the GEOScan SensorPod bus and associated data and power handling electronics. Because we expect to build 66+ GEOScan SensorPods, we can, for the first time, finally utilize the advantage of large scale production to realize a dramatic cost savings.

We continue with a brief description of some possible system sensors and some candidate science themes enabled by those sensors.

Figure 3: Outline of the main themes of the GEOScan program components. Click to Enlarge

System Sensors

The overarching goal of the System Sensor Program is to enable revolutionary science by making dense and global measurements that enable new techniques for imaging the Earth environment. While one of the primary tasks of both the Steering Committee and the Working groups is the selection of the three System Sensors, we can at this time identify the necessary characteristics that the sensors must possess. The sensors must be comparatively low cost (~100k per sensor or less), they must be readily available in large quantities for delivery within 2 years, and they must reliably operate in the radiation and thermal environment of low earth orbit. This leads us primarily, but not exclusively, to COTS sensors that have been adapted for space use, two clear examples are GPS and white light or visible color imaging. Further these System Sensors must also enable dramatic new scientific capabilities and provide data that is of highest level of interest to a broad range of Geoscience disciplines.

Hosted PI Sensors

The overarching goal of the Hosted Sensor program is to provide an unprecedented opportunity to expand educational and small business involvement in science and space engineering by dramatically reducing the barriers to entry. Within each GEOScan SensorPod, we plan to have approximately 1U (10x10x10 cm) of available volume with either a ram or nadir face opening available. This presents the opportunity to offer community involvement with a "cube-sat like" program with significant differences and advantages over traditional cube-sat missions. Primarily, the overhead, risk, and cost of producing a space craft bus and acquiring ground systems for data transfer are eliminated. This will free the scientists and students to focus on the engineering of the instrument and the science of the acquired data. We expect the Hosted Sensor PI's to be funded independently with integration costs and guidance provided by JHU/APL and other team members.

GEOScan Working Groups

We held a planning workshop March 27-30 and achieved several critical goals before the GEOScan program could be pursued in earnest. The attendees included over 100 discipline scientists, cube-sat and low-cost satellite engineers, systems engineers and student participants, government officials and Industry representatives. Numerous candidate science and sensor options were presented, and working groups are forming to follow up on these necessary items prior to program proposal. The following items are in preparation and GEOScan working groups are tasked with making recommendations to the steering committee:

• Evaluate, in detail, the potential scientific value of the proposed GEOScan program for each of the Geosciences disciplines.
• Help select three baselined system sensors that will fly on all 66+ satellites.
• Define System Sensor Science goals based upon the baselined sensor's capabilities.
• Define hosted sensor program and estimate participant readiness, number of capable PIs, and candidate science based on relevant launch timeline and feasibility requirements.
• Establish GEOScan SensorPod science and engineering requirements and conduct flow down analysis for each.
• Make final recommendations to steering committee for the NSF program proposal.

Steering Committee

GEOScan has established a Scientific and Engineering Steering Committee. This committee consists of approximately 16 members, including scientific leaders from each of the relevant disciplines within Geoscience including: space, upper and middle atmosphere, lower atmosphere, oceans, and Earth science. Several members were chosen for their experience in both low-cost space and space missions in general. The appropriate representatives from NSF, Iridium and APL management serve as ex officio members.

A steering committee meeting is being held June 9-10, 2011 at JHU/APL that is open to the community, please email: Lars Dyrud for details.

Meeting Agenda