A defunct NASA satellite, Van Allen Probe A, weighing about 600 kg (1,323 pounds), is re-entering Earth’s atmosphere after nearly 14 years in orbit.
Although such re-entries may raise safety concerns, experts have clarified that the risk to human life is extremely low, as most of the spacecraft will burn up during atmospheric entry.
About Van Allen Probe A
Van Allen Probe A was launched by NASA in August 2012, along with its twin spacecraft (Van Allen Probe B), as part of a mission to study the Van Allen radiation belts surrounding Earth.
- The mission was initially planned for two years, but it continued to function successfully for nearly seven years, collecting valuable scientific data before being shut down in 2019 due to fuel exhaustion.
- The probes were named after James Van Allen, the scientist who discovered Earth’s radiation belts.
Van Allen Radiation Belts
The Van Allen belts are doughnut-shaped regions of high-energy charged particles trapped by Earth’s magnetic field.
These belts play a crucial role in:
- Protecting Earth from solar radiation and cosmic rays
- Shielding satellites, astronauts, and communication systems from harmful space particles
- Helping scientists study space weather, which affects GPS, satellites, and power systems
Radiation Belt Studies Help in:
- Designing radiation-resistant satellites
- Protecting astronauts
- Improving space mission planning
Mission Significance
The Van Allen Probes significantly improved understanding of:
- Earth’s radiation environment
- Impact of solar storms and solar wind
- Behaviour of charged particles in space
The data collected has contributed to making space missions safer and more reliable.
Reason for Early Re-entry
After the mission ended in 2019, the satellite remained in orbit. Over time, its orbit began to decay due to atmospheric drag.
Originally, NASA had estimated re-entry around 2034, but this timeline changed due to increased solar activity.
- During the recent solar maximum (2024), the Sun’s activity increased
- This caused Earth’s upper atmosphere to expand
- Increased atmospheric density led to greater drag, pulling the satellite down faster
As a result, the spacecraft is re-entering earlier than expected.
Risk Assessment
- Most of the spacecraft will burn up due to extreme heat and friction during re-entry
- A few small components made of heat-resistant materials may survive
However, the risk to humans is extremely low:
| Parameter | Details |
| Probability of injury | ~1 in 4,200 |
| Earth’s surface coverage | ~70–71% water |
| Likely landing area | Oceans or remote regions |
Thus, the chances of debris causing harm are considered negligible.
Status of Twin Satellite
- Van Allen Probe B is still in orbit
- Expected to re-enter Earth’s atmosphere before 2030
Re-entry as a Common Space Event
Re-entry of defunct satellites is a routine phenomenon in space operations.
Most old spacecraft:
- Gradually lose altitude
- Burn up in the atmosphere
- Leave minimal or no debris
This event is part of the natural lifecycle of satellites.
About NASA
| Feature | Details |
| Full Form | National Aeronautics and Space Administration |
| Established | 1958 |
| Country | United States |
| Role | Space exploration, scientific research |
Space Weather
- Refers to: Conditions in space influenced by the Sun
- Includes:
- Solar flares
- Solar wind
- Geomagnetic storms
- Impacts:
- Satellites
- GPS systems
- Communication networks
Solar Cycle
- Duration: ~11 years
- Phases:
- Solar minimum (low activity)
- Solar maximum (high activity)
- During solar maximum:
- Increased radiation
- Stronger atmospheric expansion
Atmospheric Drag
- Resistance faced by objects in low Earth orbit due to thin atmospheric particles
- Causes:
- Gradual loss of altitude
- Eventual re-entry