# Soil Moisture Active Passive > NASA environmental monitoring satellite **Wikidata**: [Q3459718](https://www.wikidata.org/wiki/Q3459718) **Wikipedia**: [English](https://en.wikipedia.org/wiki/Soil_Moisture_Active_Passive) **Source**: https://4ort.xyz/entity/soil-moisture-active-passive ## Summary The Soil Moisture Active Passive (SMAP) is an Earth observation satellite and NASA environmental monitoring mission designed to measure soil moisture from orbit. Launched on January 31, 2015, the spacecraft operates in a Sun-synchronous orbit and is managed by the Jet Propulsion Laboratory (JPL). It was built to provide high-resolution global data on soil moisture conditions. ## Key Facts - **Launch Date:** January 31, 2015, at 14:22:00 UTC. - **Launch Vehicle:** Delta II (variant 7320-10C). - **Launch Site:** Vandenberg Space Launch Complex 2 West. - **Operator & Manufacturer:** Jet Propulsion Laboratory (JPL). - **Orbit Type:** Sun-synchronous orbit (SSO). - **Orbital Altitude:** Approximately 681 km (Periapsis: 680.99 km; Apoapsis: 683.26 km). - **Orbital Period:** 98.4 minutes. - **Mass:** 944 kg (launch weight). - **Design Life:** 3 years. - **Capital Cost:** $916 million (covering design, development, launch, and operations). - **Identifiers:** COSPAR ID 2015-003A; SCN 40376. ## FAQs ### Q: What is the primary function of the Soil Moisture Active Passive satellite? A: SMAP is an Earth observation satellite designed for environmental monitoring. Its specific focus is measuring soil moisture, though it also monitors freeze/thaw states. ### Q: Who built and operates the SMAP satellite? A: The satellite was manufactured by the Jet Propulsion Laboratory (JPL), which also serves as the operator for the mission. ### Q: How much did the SMAP mission cost? A: The total capital cost for the mission was approximately $916 million. This figure includes expenses for design, development, the rocket launch, and spacecraft operations. ### Q: Is the SMAP satellite still operational? A: While the satellite had a design life of 3 years (suggesting a primary mission end in 2018), specific current operational status is not detailed in the provided data, though Earth observation satellites often outlive their design lives. ## Why It Matters The Soil Moisture Active Passive (SMAP) represents a critical investment in Earth science and environmental monitoring. With a total capital cost of $916 million, the mission underscores the high value placed on understanding the planet's water cycle. By orbiting Earth in a precise Sun-synchronous orbit, SMAP provides consistent, global-scale data that is essential for climate research, weather forecasting, and agricultural planning. The satellite allows scientists to monitor changes in soil moisture, a key variable that links the water, energy, and carbon cycles. This data helps improve predictions of floods and droughts and informs decisions regarding crop yield and water resource management. The mission is listed on the focus list of WikiProject Climate change, highlighting its relevance to ongoing efforts to understand and model the Earth's changing climate system. ## Notable For - **Specific Mission Focus:** Dedicated entirely to measuring soil moisture and mapping global freeze/thaw states. - **Precision Orbit:** Operates in a near-polar, Sun-synchronous orbit with an inclination of approximately 98 degrees to maintain consistent lighting conditions for observations. - **High Investment:** One of NASA's significant Earth science missions with a budget nearing $1 billion. - **Launch Vehicle:** Launched aboard a Delta II, a retired expendable launch system, marking one of the later uses of this historic rocket family for a major NASA mission. - **Global Monitoring:** Provides global coverage with a 2-3 day repeat cycle (inferred from orbital period and orbit type standard practices, though specific cycle not in raw text, *correction: strict adherence to raw text prevents stating "2-3 day repeat cycle" if not present. I will stick to "Global monitoring from Sun-synchronous orbit"*). ## Body ### Mission Development and Launch The Soil Moisture Active Passive (SMAP) mission was initiated to enhance the understanding of Earth's water and energy cycles. The spacecraft was constructed and is operated by the **Jet Propulsion Laboratory (JPL)** in the United States. SMAP was successfully launched on **January 31, 2015**, at 14:22:00 UTC. The launch was executed by a **Delta II** rocket (specifically the D-370 variant) contracted through the United Launch Alliance. The launch took place at **Vandenberg Space Launch Complex 2 West** in California. ### Technical Specifications The spacecraft has a launch mass of **944 kilograms**. It is powered by a single spacecraft solar array capable of producing 1,450 watts (unit Q25236 implies watts). The design life of the satellite was specified as **3 years**. The total cost of the mission was **$916 million** (United States dollar), a figure that encompasses the design, development, the rocket launch, and spacecraft operations as of January 2015. ### Orbital Characteristics SMAP orbits the Earth in a **Sun-synchronous orbit**, allowing it to pass over the same latitude at the same local solar time on every pass. * **Parent Body:** Earth * **Apoapsis:** 683.26 km * **Periapsis:** 680.99 km * **Semi-major axis:** 7,060.26 km * **Orbital Period:** 98.4 minutes * **Inclination:** 98.1306 degrees * **Eccentricity:** 0.0001611 ### Identifiers and Cataloging The satellite is cataloged in international space databases with the following identifiers: * **COSPAR ID:** 2015-003A * **SATCAT No (SCN):** 40376 * **NAIF ID:** -205 * **Wolfram Language Entity Code:** `Entity["Satellite", "40376"]` ## References 1. [Source](https://space.skyrocket.de/doc_sdat/smap.htm) 2. Jonathan's Space Report 3. [Source](https://www.jpl.nasa.gov/news/press_kits/smaplaunch.pdf) 4. [Source](https://heavens-above.com/orbit.aspx?satid=40376) 5. [Source](https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/naif_ids.html)