![The Orbital Debris Issue: Estimating the population of smaller debris that cannot be tracked but pose a risk to human and robotic spaceflight is the responsibility of the Orbital Debris Program Office (ODPO). Approximately 500,000 marble-sized debris objects are predicted to be in Earth’s orbit and over 100,000,000 objects of 1 mm or smaller are estimated. Even the smallest objects are dangerous when traveling at extreme orbital speeds. Credit: NASA.](_pictures/_slideshow/orbital-debris.jpg)
![The Orbital Debris Program Office is a leader in the development of national and international polices focused on the mitigation of debris and the risk that they pose. ODPO developed the first set of NASA orbital debris mitigation requirements in 1995 and provides support to NASA’s Office of Safety and Mission Assurance. This includes maintaining procedures and standards for limiting debris in the orbital environment. Credit: 1981 painting copyright William K. Hartmann, Senior Scientist Emeritus, Planetary Science Institute.](_pictures/_slideshow/mitigation-policy.jpg)
![Debris Measurements: ODPO conducts measurements of near-Earth orbital debris with ground-based radars and optical telescopes. Further measurements are also collected through space-based sensors and by examining spacecraft surfaces that have returned to Earth. This data is then used by ODPO software modeling tools to predict possible risks to spacecraft. Image Credit: Sqn Ldr Greg Cooke RAF.](_pictures/_slideshow/debris-measurements.jpg)
![Debris Environment Modeling: ODPO has developed reliable software tools, such as ORDEM and a LEO-to-GEO environmental debris model (LEGEND), to determine the risk to current and future spacecraft. These tools, which leverage the team's expansive debris database, also enable study of how the debris environment will react to future mitigation practices. Credit: NASA ODPO.](_pictures/_slideshow/debris-modeling.jpg)
![Reentry Risks: Risks to humans on the ground from rocket bodies and spacecraft reentering the Earth’s lower atmosphere are another concern of the ODPO. Two ODPO-developed tools, the Debris Assessment Software (DAS) and the Object Reentry Survival Analysis Tool (ORSAT), are used to compute reentry survivability and predict possible risk. Credit: NASA ODPO.](_pictures/_slideshow/reentry-risk.jpg)
ORDEM 3.2
ORDEM 3.2 is for engineering solutions requiring knowledge
and estimates of the orbital debris environment. It can
also be used as a benchmark for ground-based debris
measurements and observations.
LEGEND
LEGEND is a full-scale, three-dimensional, debris evolutionary
model that is the primary foundation to the ODPO's study of
the long-term debris environment projection and how it will
evolve over time.
DAS 3.2
The Debris Assessment Software utility will be periodically
updated by NASA to reflect the latest understanding of the
man-made debris environment in Earth orbit.
Quarterly News
The ODQN publishes some of the latest advancements in orbital debris
research, offers news and statistics, presents project reviews
and meeting reports, and details about upcoming events.
![The NASA Orbital Debris Program Office (ODPO) logo.](/_pictures/ODPO_Logo_final_v2_small.png)
The NASA Orbital Debris Program Office (ODPO) is a Delegated Program in the Office of Safety and Mission Assurance (OSMA) at NASA HQ. The ODPO has taken the international lead in conducting measurements of the orbital environment and in developing the technical consensus for adopting mitigation measures to protect the users within it. Located at the Johnson Space Center, the Office continues to develop an improved understanding of the orbital debris environment and measures that can be taken to control debris growth.