Trade-space Analysis Tool for Designing Constellations (TAT-C) Government Release

06/18/2020  The Trade-space Analysis Tool for designing Constellations (TAT-C) provides a framework to explore new ways to design Earth science missions. The software allows the user to ask questions, such as:

• Which type of constellations should be chosen?
• How many spacecraft should be included in the constellation?
• Which design has the best cost/risk value?

TAT-C will address the strong and growing interest in implementing future NASA Earth Science missions as Distributed Spacecraft Missions (DSMs), particularly with SmallSats. The goal is to provide the Earth Science community with a powerful tool to quickly design novel DSMs or augment existing missions to optimize their science return. The software facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori science goals.

TAT-C’s modular architecture includes a knowledge base, a cost and risk module, an orbit and coverage module and a carefully designed trade-space search iterator and user interface. TAT-C enables users to quickly assess, visualize and validate a very large number or potential architectures in response to input and output science requirements.

How do I access the software?

The first version of the TAT-C software is now available for government release and can be obtained on the NASA Software Catalog website. Instructions follow:

1. Visit: and search for “Trade-space Analysis Tool for designing Constellations” or “TAT-C”.
2. Click the “Download Now” button. This will take you to the online software usage agreement (SUA) that will need to be filled out. Even government purpose software is distributed using the SUA process.

Why design a constellation?

Technology advances are creating opportunities to make new measurements and to continue others within an optimized architecture. SmallSats equipped with science-quality instruments and machine learning techniques can handle large volumes of data.

One of the factors driving autonomous systems management development is the realization that dynamic observations are based on transient events. These can also be observed with sensor webs that produce data integrated from multiple vantage points, models and in-situ instruments to influence which observations to make and when to make them.

The recently defined “New Observing Strategies (NOS)” concept enables users to generalize the idea of Sensor Webs while taking advantage of recent technology advances such as instrument and spacecraft miniaturization, onboard processing capabilities and advanced AI techniques onboard and on the ground. Each node of these new Intelligent Sensor Webs could be an individual sensor, a web of sensors or a constellation mission. In the future, NOS will help provide new observations and a unified picture of Earth’s physical processes and natural phenomena. In this context, the optimal design of constellations responding to specific science goals has become very important.

Future versions of TAT-C will include new mission configurations, such as bi-static radars and occultation missions, and will support additional trades on instruments, spacecraft sizes, launch and onboard processing hardware and computations choices. It will also extend cost and risk analyses to consider requirements for ground operations and mission re-planning.

TAT-C is funded under the Advanced Information Systems Technology program, which is part of NASA’s Earth Science Technology Office.

For more information, please contact Jacqueline Le Moigne at