astronomy

Lunar Reconnaissance Orbiter

Lunar Reconnaissance Orbiter is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lunar Reconnaissance Orbiter rather than just read about it. In short: The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon.

Key takeaways

Lunar Reconnaissance Orbiter belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lunar Reconnaissance Orbiter to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lunar Reconnaissance Orbiter from memory before moving on to harder problems.

Reference excerpt

The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic missions to the Moon. Its detailed mapping program is identifying safe landing sites, locating potential resources on the Moon, characterizing the radiation environment, and demonstrating new technologies. Launched on June 18, 2009, in conjunction with the Lunar Crater Observation and Sensing Satellite (LCROSS), as the vanguard of NASA's Lunar Precursor Robotic Program, LRO was the first United States mission to the Moon in over ten years. LRO and LCROSS were launched as part of the United States's Vision for Space Exploration program. The probe has made a 3-D map of the Moon's surface at 100-meter resolution and 98.2% coverage (excluding polar areas in deep shadow), including 0.5-meter resolution images of Apollo landing sites. The first images from LRO were published on July 2, 2009, showing a region in the lunar highlands south of Mare Nubium (Sea of Clouds). The total cost of the mission is reported as US$583 million, of which $504 million pertains to the main LRO probe and $79 million to the LCROSS satellite. LRO has enough fuel to continue operations until 2027.

Mission

Developed at NASA's Goddard Space Flight Center, LRO is a large (1,916 kg/4,224 lb) and sophisticated spacecraft. Its mission duration was planned for one year, but has since been extended numerous times after review by NASA. After completing a preliminary design review in February 2006 and a critical design review in November 2006, the LRO was shipped from Goddard to Cape Canaveral Air Force Station on February 11, 2009. Launch was planned for October 2008, but this slid to April as the spacecraft underwent testing in a thermal vacuum chamber. Launch was rescheduled for June 17, 2009, because of the delay in a priority military launch, and happened one day later, on June 18. The one-day delay was to allow the Space Shuttle Endeavour a chance to lift off for mission STS-127 following a hydrogen fuel leak that canceled an earlier planned launch. Areas of investigation include selenodetic global topography; the lunar polar regions, including possible water ice deposits and the lighting environment; characterization of deep space radiation in lunar orbit; and high-resolution mapping, at a maximum resolution of 50 cm/pixel (20 in/pixel), to assist in the selection and characterization of future landing sites. In addition, LRO has provided images and precise locations of landers and equipment from previous and current lunar missions, including the Apollo sites. In 2024, it confirmed the highly accurate landing site of the first successful Japanese SLIM soft landing.

Instruments

The orbiter carries a complement of six instruments and one technology demonstration:

Cosmic Ray Telescope for the Effects of Radiation (CRaTER) The primary goal of the Cosmic Ray Telescope for the Effects of Radiation is to measure and characterize local energy transfer by charged particles in lunar orbit and its biological impacts. Diviner The Diviner Lunar Radiometer Experiment measures lunar surface thermal emission to provide information for future surface operations and exploration. Lyman-Alpha Mapping Project (LAMP) The Lyman-Alpha Mapping Project peers into permanently shadowed craters in search of water ice, using ultraviolet light generated by stars as well as the hydrogen atoms that are thinly spread throughout the Solar System. Lunar Exploration Neutron Detector (LEND) The Lunar Exploration Neutron Detector provides measurements, creates maps, and detects possible near-surface water ice deposits. Lunar Orbiter Laser Altimeter (LOLA) The Lunar Orbiter Laser Altimeter investigation provides a precise global lunar topographic model and geodetic grid.

Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) The Lunar Reconnaissance Orbiter Camera addresses the measurement requirements of landing site certification and polar illumination. LROC comprises a pair of narrow-angle cameras (NAC) and a single wide-angle camera (WAC). The two Narrow Angle Cameras feature a Cassegrain (Ritchey-Chretien) primary optics at f/3.59, with primary mirror diameter of 19.5 cm, using push-broom imaging. At its original altitude of about 50 km, each NAC images pixels about 0.5-meter across, and the swath, which is 5064 pixels wide, is about 2.5 km across. The orbit was raised in 2011 to be elliptical, reducing the resolution in parts of the orbit to 2.0 m/px.: LROC has flown several times over the historic Apollo lunar landing sites at 50 km (31 mi) altitude. The Lunar Roving Vehicles and Lunar Module descent stages and their respective shadows are clearly visible, along with other equipment previously left on the Moon. Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) The WAC provides visible and UV images at a scale of 100 meters/pixel in seven color bands over a 60 km swath. Image format is 1024 x 1024 pixels, with a field of view of 92° (monochrome), 61° (visible light), and 59° in the UV. Mini-RF The Miniature Radio Frequency radar demonstrated new lightweight synthetic aperture radar (SAR) and communications technologies and located potential water-ice.

Names to the Moon Prior to the LRO's launch, NASA gave members of the public the opportunity to have their names placed in a microchip on the LRO. The deadline for this opportunity was July 31, 2008. About 1.6 million names were submitted.

Mission progress

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Lunar Reconnaissance Orbiter

Start with the simplest possible case. Write down what Lunar Reconnaissance Orbiter claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lunar Reconnaissance Orbiter before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lunar Reconnaissance Orbiter ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lunar Reconnaissance Orbiter

In research: Lunar Reconnaissance Orbiter appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lunar Reconnaissance Orbiter in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lunar Reconnaissance Orbiter is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2009 in Florida, June 2009 in the United States, Laser communication in space, so understanding it makes those chapters shorter.
In everyday life: Look for Lunar Reconnaissance Orbiter outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lunar Reconnaissance Orbiter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lunar Reconnaissance Orbiter means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lunar Reconnaissance Orbiter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lunar Reconnaissance Orbiter in simple terms?

Why does Lunar Reconnaissance Orbiter matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lunar Reconnaissance Orbiter?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lunar Reconnaissance Orbiter.