In 1996, NASA started a New Millenium Program (NMP), designed to identify, develop, and flight-validate key instrument and spacecraft technologies that can enable new or more cost-effective approaches to conducting science missions in the 21st century. The first of these New Millenium Program Earth-orbiting missions is Earth Observing-1 (EO-1), an advanced land-imaging mission that will demonstrate new instruments and spacecraft systems. EO-1 will validate technologies contributing to the significant reduction in cost of follow-on Landsat missions.

The EO-1 mission logo. Photo: NASA-GSFC

Instruments
The three primary instruments on the EO-1 observatory are the Advanced Land Imager, the Hyperion and the Linear Imaging Spectrometer Array (LEISA) Atmospheric Corrector (AC).

The Advanced Land Imager (ALI) employs novel wide-angle optics and a highly integrated multispectral and panchromatic spectrometer. MIT Lincoln Laboratory, Lexington, Mass. developed the ALI under project management by NASA's Goddard Space Flight Center with NMP instrument team members: Raytheon/Santa Barbara Remote Sensing (SBRS) for the focal plane system and Sensor Systems Group, Inc. (SSG) Wilmington, Mass. for the optical system.

The Hyperion instrument provides a new class of Earth observation data for improved Earth surface characterization. The Hyperion capabilities provide resolution of surface properties into hundreds of spectral bands versus the ten multispectral bands flown on traditional Landsat imaging missions. Through this large number of spectral bands, complex land eco-systems shall be imaged and accurately classified. TRW, Redondo Beach, Calif, developed the Hyperion instrument under project management by Goddard.

Earth imagery is degraded by atmospheric absorption and scattering. The Linear Imaging Spectrometer Array (LEISA) Atmospheric Corrector (AC) will provide the first space-based test of an Atmospheric Corrector (AC) for increasing the accuracy of surface reflectance estimates. The AC provides the capabilities by a compact and simple bolt-on design for future Earth Science, land-imaging missions. Goddard's Applied Engineering and Technology Directorate (AETD) developed the AC.

Drawing notes the various instruments and technologies of EO-1. Photo: NASA-GSFC

Technologies
New Millennium Program's Earth Observing-1 (EO-1) mission will provide for the on-orbit demonstration of a high data rate, low mass X-Band Phased Array Antenna (XPAA) for down-linking imaged data from the EO-1solid state recorder. The XPAA offers significant benefits over current mechanically pointed parabolic antennas, including the elimination of deployable structures, moving parts, and the torque disturbances that moving antennas impart to the spacecraft.

Future generations of Earth Science missions will generate terrabytes of data daily which must be returned to Earth. The XPAA provides a low cost, low mass, highly reliable means of transmitting hundreds of megabits per second to low cost ground terminals. The XPAA also has the inherent advantage of providing a body-fixed design which can allow simultaneous capture and transmission of data, avoiding perturbations to instrument measurements. The antenna was developed for GSFC by Boeing Phantom Works located in Seattle, Wash.

Enhanced formation flying (EFF) technology for onboard constellation and formation control will enable a large number of spacecraft to be managed with a minimum of ground support. The result will be a group of spacecraft with the ability to detect errors and cooperatively agree on the appropriate maneuver to maintain their desired positions and orientations. The EFF technology is applicable to any mission class, be it low-Earth or Deep Space, that desires to fly multiple satellites autonomously while gaining the added benefit of enabling science and reducing mission operations costs.

The EFF technology features flight software that is capable of autonomously planning, executing, and calibrating routine spacecraft maneuvers to maintain satellites in their respective constellations and formations.

Enhanced Formation Flying (EFF) technology enables many small, inexpensive spacecraft to fly in formation and gather concurrent science data in a "virtual platform". This "virtual platform" concept lowers total mission risk, increases science data collection and adds considerable flexibility to future Earth and space science missions.

The New Millennium Program's Earth Observing-1 mission (EO-1) will provide for the first on-orbit demonstration of a low mass, low cost, dependable electromagnetic Pulse Plasma Thruster (PPT) propulsion unit for precision attitude control.

Illustration of EO-1. Photo: NASA-GSFC

The PPT will be used to maintain fine pitch attitude control pointing requirements for EO-1 while meeting stringent electromagnetic and contamination constraints for the mission. A series of fine pitch pointing maneuvers will be conducted with the PPT after the baseline EO-1 mission has completed its primary land scene comparison with LANDSAT-7.

The PPT is applicable to Earth and space science missions requiring precision pointing and control. For example, the Origins Program will require precision alignment and coordination of multiple spacecraft. The PPT is a perfect candidate for these types of missions, and avoids liquid propellant sloshing which could effect instrument measurement.

Use of the PPT is particularly valuable in small spacecraft by offering a low mass and lower cost alternative to attitude control systems requiring reaction wheels and momentum unloading components. Also, the PPT may be an excellent low cost and low mass alternative for conventional delta-V propulsion systems. All of these benefits will help reduce the cost and weight of new Earth and space science missions, and will enable greater science instrumentation to be performed on any given mission.

The Light Weight Flexible Solar Array (LFSA) is a light weight photovoltaic solar array system. Full flight validation of the Light Weight Flexible Solar Array (LFSA) will enable the production of simpler and lower weight solar arrays. This will enable increased science measurement instrumentation to be integrated on a mission (increased payload mass fraction) enabling greater scientific return for each mission.

Earth imagery is degraded by atmospheric absorption and scattering. The New Millennium Program's Earth Observing-1 Mission (EO-1) will provide the first space-based test of an Atmospheric Corrector (AC) for increasing the accuracy of surface reflectance estimates.

Use of Carbon-Carbon Radiators (CCR) may simplify thermal radiator design in some applications (e.g., No need for actively cooled radiators) and support increased science payload mass fraction for future missions.

The Wideband Advanced Recorder Processor (WARP) is a high rate solid state recorder on EO-1. It will be used to capture high rate range data from the Advanced Land Imager (ALI), Atmospheric Corrector (AC), and the Hyperion instruments. The input data rate to the WARP is four to five times greater than any NASA mission flying today.

The WARP incorporates a number of high density electronic board advanced packaging techniques and will provide the highest rate solid state recorder NASA has ever flown. Its basic architecture and underlying technologies will be required for future earth imaging missions which need to collect, store and process high rate land imaging data.

EO-1's high-rate imaging (almost 1 gigabit per second when all three instruments are on), required engineers to design and build a specific subsystem to handle the data rate and still maintain flight constraints of compact size and low power usage. Although not officially part of the NMP/EO-1 validation list, the Wideband Advanced Recorded Processor (WARP) is a solid-state recorder with capability to record data from all three instruments simultaneously and store up to 48 Gbits (2-3 scenes) of data before it is transmitted to the ground. WARP's compact design, advanced solid-state memory devices (3 dimensional RAM stacks) and packaging techniques enables EO-1 to collect and downlink all recorded data.