(U) The purpose of this particular light detection and ranging (LIDAR) sensor, either alone or as a part of a combination of instruments aboard NPOESS and NEMSS satellites, is to measure atmospheric winds' speed and direction from the ground to 25 km.
(U) LIDAR could be used to measure winds, temperature, and moisture profiles. There are currently several LIDAR wind sensing concepts under development. Since wind is the number one unaccommodated NPOESS capability, an operational Wind LIDAR is essential and must be fully demonstrated before the NPOESS technology freeze date.
(U) LIDAR transmits light to a target and measures its return. Coherent LIDAR measures aerosol returns and direct detection measures molecular returns. Key identified technology needs include: for coherent detection a 2 micron long-pulse, narrow-band, high beam quality, diode-pumped solid state laser (Sparcle); for direct detection a narrow-band, diode-pumped Nd:YAG laser (Zephyr); and WFOV narrow-band optical filters. The first space demonstration of the technology was the LITE Shuttle experiment 9-20 Sep 94. The device did not scan and had old laser technology with generous shuttle power. Additional Space Shuttle demo is scheduled for 2000 (MTPE EO-2), and a free flyer STP experiment is proposed for 2001 (EELV).
(U) A Wind LIDAR is the most promising of the wind measurement concepts under consideration and would be used to measure atmospheric winds from the ground up to 25 km. The LIDAR sensor measures velocity by determining the Doppler shift of laser radiation from atmospheric aerosols carried by the wind. Flying a Wind LIDAR on NPOESS is one option; however, it may not satisfy the refresh rate deficiency. There are several surveillance systems that could also use LIDAR and provide additional capability.
(U) NPOESS has validated requirements for global tropospheric winds, however LIDAR is not currently part of the baseline program. The TPIPT is working with NASA and others to establish funding for technology demos or instrument development. Criteria for a positive NPOESS decision in 2001 (to support C1 for 2007-8 launch) include: available space and power to accommodate the payload after all other requirements are met; successful demonstration of technology on a free flyer; successful demonstration of data value to civilian and military users; detailed cost and schedule info for the instrument; and additional NPOESS funding.
(U) TPIPT recognizes that NPOESS may not provide a platform for space based LIDAR, and surveyed the community for other solutions, including: Lockheed Martin; Orbital Sciences; Hayes Fisk's Weather Sat AFRL; NASA Marshall's SPARCLE coherent doppler LIDAR; NASA Goddard's Zephyr direct detection Lidar. TPIPT added FY00 POM proposal for SPARKLE, and the environmental monitoring development plan will document technologies needed for these solutions and update its technology roadmap.
(U) LIDAR's primary limitations are: it cannot detect below non-cirrus cloud tops; and atmospheric aerosol concentrations are too low above 25 km to receive useful measurements.
(U) To be supplied.
|Improved Space Env. Models||Improved Space Environment Models|
|Terrestrial Weather Sensor Upgds||Terrestrial Weather Sensor Upgrades|
|Space-Based Sensors||Space Based Sensors|
|ENVIRONMENTAL MONITORING||SPACE FORCE ENHANCEMENT: ENVIRONMENTAL MONITORING|
(U) National Security Space Road Map Team, NSSA, Open Phone: (703) 808-6040, DSN 898-6040.
(U) 21 November 1997
(U) Road Map Production Date: 23 June 2001