NASA Satellite Laser Ranging Moblas 4 Monument Peak, CA LRO and HPWREN Scott Wetzel NASA Satellite Laser Ranging Program Near Earth Networks Programs Honeywell Technology Solutions Incorporated 2009 HPWREN Users Meeting Palomar Observatory November 5, 2009

NASA Satellite Laser Ranging, Monument Peak, CA

SLR generates unambiguous centimeter accuracy orbits! What is the Satellite Laser Ranging (SLR) Technique SLR is…The precise measurement of the range between a SLR ground station and a retroreflector- equipped satellite using ultrashort laser pulses. Simple range measurement Space segment is passive Night / Day Operation Near real-time global data availability Satellite altitudes from 400 km to 20,000 km and to the Moon Now to Lunar Orbiter (LRO) Satellite Orbit Accuracy ~ 1-2 cm (LAGEOS) LAGEOS Satellite ICESat Retroreflector SLR generates unambiguous centimeter accuracy orbits!

What and Why is the LRO? Return to the Moon: The United States has begun a program to extend human presence in the solar system, beginning with a return to the Moon. Returning to the Moon enables the pursuit of scientific activities that address our fundamental questions about the history of Earth, the solar system, and the universe and about our place in them. Returning to the Moon will allow us to test technologies, systems, flight operations, and exploration techniques to reduce the risk and enable future missions to Mars and beyond. The first step in this endeavor is the Lunar Reconnaissance Orbiter LRO), An unmanned mission to create a comprehensive atlas of the Moon’s features and resources to aid in the design of a lunar outpost. LRO follows in the footsteps of Ranger, Lunar Orbiter, and Surveyor. These predecessors to the Apollo missions searched for the best possible landing sites. The goals of LRO go beyond the requirements of these previous missions because building a lunar outpost means spending extended periods on the moon. LRO focuses on the selection of safe landing sites, identification of lunar resources, and studies of how the lunar radiation environment affect humans. LRO has several instruments that will help NASA characterize the moon's surface. The powerful equipment will bring the moon into sharper focus and reveal new insights about the celestial body nearest Earth. The LRO payload, comprised of six instruments and one technology demonstration, will provide key data sets to enable a human return to the moon….LOLA is

New SLR Target – Lunar Reconnaissance Orbiter (LRO) The objective of the Lunar Reconnaissance Orbiter (LRO) Laser Ranging (LR) system is to… Enable the spacecraft to achieve precision orbit determination. The LR will make one-way range measurements via laser pulse time-of-flight from Earth to LRO, and will determine the position of the spacecraft at a sub-meter level with respect to Earth and the center of mass of the Moon. Ranging will occur whenever LRO is visible in the line of sight from participating Earth ground tracking stations. (Including Moblas 4) The LR consists of two primary components. The flight system, mounted on the LRO high gain antenna, and a fiber optic cable that routes the signal to the Lunar Orbiter Laser Altimeter (LOLA) instrument on LRO. The LOLA instrument receiver electronics record the time of the laser signal based on an ultrastable crystal oscillator, and provide the information to the onboard LRO data system for storage and/or transmittal to the ground through the spacecraft radio frequency link. The ground system will receive near real time feedback from LRO as to the success of the one way ranging. This requires fast, reliable communications between Moblas 4 and the LRO.

The Problem with Working in a Remote Location The challenge with working in a remote location is that of connectivity with the outside world… Comm tower Moblas 4

How to Achieve Success with Moblas 4 and LRO Reliable Communications from HPWREN is needed to provide feedback on Moblas 4 LRO ranging attempts

For More Information on SLR and LRO For more information on Satellite Laser Ranging (SLR): http://Ilrs.gsfc.nasa.gov For more information on the Lunar Reconnaissance Orbiter (LRO): http://www.nasa.gov/mission_pages/LRO/main/index.html For more information on the Lunar Orbiter Laser Altimeter (LOLA): http://lunar.gsfc.nasa.gov/lola/ For more information on LOLA Laser Ranging (LOLA LR) http://lrolr.gsfc.nasa.gov/lrolr_home.html From a 50 km mapping orbit, LROC reveals more details of the Apollo 12 landing site.

Ranging to LRO at the Goddard Space Flight Center