VNREDSAT 1

VNREDSAT-1 (also rendered as VNREDSat-1) is a Vietnamese Earth observation satellite operating in a sun-synchronous low Earth orbit. Catalogued by the United States Space Command under NORAD ID 39160 and carrying the international designator 2013-021B, the spacecraft was launched on 6 May 2013 and remains in orbit as of this writing. It holds a significant place in the history of Vietnamese space technology as the country's first domestically operated optical Earth-imaging satellite, representing an early and consequential step in Vietnam's development of an independent space capacity.

Mission and Purpose

The primary mission of VNREDSAT-1 centres on the observation and study of Vietnam's land surface, coastlines, and surrounding environment from orbit. Its core objectives encompass monitoring the progression and regional effects of climate change, providing data that supports the prediction and mitigation of natural disasters such as floods, landslides, and typhoons, and contributing to the more efficient management and conservation of the country's natural resources. Vietnam's geography — a long, narrow country exposed to the South China Sea, with extensive river deltas, dense forests, and a coastline vulnerable to storm surges — makes orbital observation particularly well-suited to informing national planning and emergency response.

The satellite's optical imaging capability allows ground teams to collect repeated, consistent imagery of specific regions, enabling change-detection analysis over time. This kind of time-series data is valuable for tracking deforestation rates, coastal erosion, agricultural shifts, and the aftermath of disaster events. By providing domestic access to such imagery, VNREDSAT-1 reduces Vietnam's dependence on purchasing data from foreign satellite operators and gives the Vietnam Academy of Science and Technology direct oversight of tasking priorities.

While the mission type is not formally specified in the public satellite catalog, the satellite's design and operator context make clear that land and environmental monitoring drive its operational role. No precise public record of the spacecraft's mass has been disclosed in the catalog data.

Orbit and Tracking

VNREDSAT-1 operates in a sun-synchronous orbit, a class of near-polar orbit engineered so that the satellite passes over any given point on the Earth's surface at approximately the same local solar time on each revisit. This consistency is especially important for optical Earth observation, because stable sun angles across successive passes make it far easier to compare images taken days, weeks, or months apart — shadows fall in predictable directions, and seasonal illumination differences can be isolated and studied rather than confused with surface changes.

The satellite's orbital parameters are closely matched between apogee and perigee — 683 km and 681 km respectively — indicating a very nearly circular orbit with minimal eccentricity. This near-perfect circularity ensures a consistent altitude above the ground, which in turn maintains a stable imaging geometry from one pass to the next. The orbital inclination is 97.9°, which is the retrograde angle characteristic of sun-synchronous missions: slightly past polar, allowing the orbital plane to precess at the same rate the Earth progresses around the Sun.

Each orbit takes approximately 98.2 minutes to complete. At this altitude and period, VNREDSAT-1 completes roughly 14 to 15 orbits per day, revisiting the same ground tracks on a regular cycle. The combination of altitude and inclination means the satellite provides coverage of Vietnam and the surrounding region multiple times per day across the full repeat cycle, though the exact revisit interval for any specific point depends on the satellite's swath width and pointing capability.

Observers and analysts can track VNREDSAT-1 in real time using its NORAD catalog number, 39160. The object is classified in the catalog as a payload — that is, the primary mission spacecraft, as distinct from the rocket body or any debris associated with its launch. The corresponding launch vehicle components are catalogued separately under the same launch event, 2013-021.

Design and Operator

VNREDSAT-1 was manufactured by Astrium, the European aerospace and defence company (subsequently integrated into Airbus Defence and Space). The involvement of a major European prime contractor reflects the approach taken by many emerging space nations: partnering with an established manufacturer to build the first satellite while simultaneously developing domestic expertise that can underpin future, more independent programmes.

The spacecraft is operated by the Vietnam Academy of Science and Technology (VAST), a state research institution responsible for coordinating scientific research and technological development in Vietnam. VAST's ownership and operation of the satellite places control of the data it produces within a national scientific body, allowing the imagery to serve the broader research and policy communities rather than being managed exclusively through commercial or military channels.

The satellite was launched on 6 May 2013 and reached its operational orbit around the Earth without issue. Its orbit class — sun-synchronous — was almost certainly specified from the outset of the programme, since this orbit type is the standard choice for optical observation missions that prioritise consistent, repeatable imaging conditions. The near-circular shape of the operational orbit, with apogee and perigee separated by only 2 km, indicates that the insertion was precise and that the spacecraft has maintained its profile well since deployment.

Although the public catalog does not specify the satellite's mass, Astrium-built Earth observation satellites of this generation and class typically fall within the small-to-medium satellite range, though no specific figure should be inferred from that general context alone.

Significance and Legacy

VNREDSAT-1 occupies a foundational position in Vietnamese space history. Before its launch, Vietnam had no domestically operated satellite capable of imaging the Earth's surface with its own optical sensor. The country had access to remote sensing data only through purchased imagery from international providers, limiting both the timeliness of data and Vietnam's autonomy in directing observation priorities.

By putting its own optical Earth observation satellite into orbit, Vietnam joined a group of nations in Southeast Asia and the broader developing world that have made strategic investments in space-based observation infrastructure as tools for environmental governance, disaster management, and resource planning. The satellite's focus on natural disaster preparedness is particularly resonant given Vietnam's repeated exposure to typhoons, flooding in the Mekong and Red River deltas, and landslides in its mountainous interior. Reliable, frequently updated satellite imagery can accelerate damage assessments, improve pre-disaster risk mapping, and inform longer-term land-use decisions in vulnerable zones.

VNREDSAT-1 also served as an early demonstration that Vietnamese institutions could manage a satellite programme end to end — from procurement through launch to operations — and the experience accumulated through this mission directly informed subsequent Vietnamese space ambitions. The satellite's continued presence in orbit, more than a decade after its 2013 launch, is itself a testament to the durability of its design and the stability of its sun-synchronous orbit. At altitudes in the low-to-mid hundreds of kilometres, drag from the residual atmosphere is low enough that spacecraft can remain operational for extended periods without propulsive orbit maintenance, though atmospheric drag at 681–683 km is not entirely negligible over long timescales.

The mission status and current operational condition of VNREDSAT-1 are not formally documented in the public satellite catalog, meaning it is not possible to state with certainty from catalog data alone whether the satellite remains in active imaging service or has transitioned to a non-operational but still-orbiting status. What is confirmed is that the object has not decayed or reentered the atmosphere and continues to be tracked.

How to Spot It

VNREDSAT-1 orbits at an altitude of approximately 681–683 km in a near-circular, nearly polar orbit with an inclination of 97.9°. These parameters mean the satellite passes over a wide range of latitudes, including most populated regions of the Earth, making it geometrically accessible to observers across a broad swath of the globe.

At this altitude, a satellite of this class will typically appear as a steadily moving point of light crossing the sky in a few minutes, brightening toward the middle of its pass and fading toward the horizon. The satellite does not carry any flashing lights, and any variation in brightness is the result of changing geometry between the observer, the satellite, and the Sun rather than any active illumination. Passes are only visible to the naked eye in the period around dawn and dusk, when the observer is in darkness but the satellite is still illuminated by sunlight — mid-night passes will be invisible as the spacecraft moves through Earth's shadow.

To find precise pass times, azimuth and elevation data, and visibility predictions for your location, use VNREDSAT-1's NORAD catalog number — 39160 — in any major satellite tracking application or website. The orbital period of 98.2 minutes means the satellite completes many orbits each day, and the near-polar sun-synchronous inclination ensures it overflies most locations on Earth at regular intervals throughout the week.