X Report 22 Nov 2025
Major challenges emerged with SpaceX's next-generation Starship booster testing, while Starlink deployments continued with successful launches.
SL-4 R/B (11639)
COSPAR: 1979-102B | Alt Name: Soyuz-U 47-442 Blok-I
DECAYED
Image
Additional Sources
Launch Details
Launch Date
December 12, 1979
Launch Site
PLMSC
Launch Pad
LC43/3
Launch Vehicle
Soyuz-U
Orbital Elements
NORAD ID
11639
International Designator
1979-102B
Decay Date
12/19/1979
Basic Satellite Info
Name
SL-4 R/B
Alternative Name
Soyuz-U 47-442 Blok-I
Type
Rocket Body
Status
Space Junk
Owner
RVSN
Country
USSR
Constellation
N/A
Related Satellites
Major Events
N/A
Summary
A rocket body, also commonly referred to as an upper stage or spent rocket stage, is the structural shell left behind after a rocket has delivered its payload to orbit. These large and often heavy pieces of space hardware can remain in orbit for years, posing significant collision hazards as part of the growing space debris problem. If left uncontrolled, rocket bodies have the potential to reenter Earth's atmosphere unpredictably, which can lead to falling debris in populated areas. Additionally, they risk colliding with operational satellites or the International Space Station, creating more debris and putting human life at risk.
Physical Characteristics
Length
6.7
Diameter
2.7
Span
6.7
Dry Mass
2350
Launch Mass
2350
Shape
Cyl
Radar Cross Section
Unknown
Visual Magnitude
Unknown
Color
Unknown
Material Composition
Unknown
Technical Details
Payload
11S510
Purpose
Unknown
Mission
Unknown
Manufacturer
PROG
Life Expectancy
Unknown
Bus
Blok-I
Configuration
Unknown
Motor
Unknown
Equipment
Unknown
Power System
Unknown
ADCS
Unknown
Transmitter Frequency
Unknown
Satellite Articles
View All Posts »Learn more about satellites and other related topics.
X Report 13 Feb 2025
SpaceX and NASA swap Crew Dragon for Crew-10 mission; exciting 'space jellyfish' phenomena from recent launch.
X Report 21 Apr 2025
SpaceX launches its 32nd cargo mission to the ISS, and NRO marks a milestone with over 200 satellites deployed.
X Report 30 Jun 2025
SpaceX is exploring alternative options for static fire tests amid infrastructure setbacks, emphasizing their adaptability in operations.
X Report 2 Jun 2025
SpaceX delays the launch of 23 Starlink satellites due to geomagnetic storm concerns, adjusting the schedule for an upcoming Falcon 9 mission.
The Day We Lost Apollo 1
Fifty-eight years ago, a tragic fire during a routine test transformed spacecraft design and created the foundation of modern spaceflight safety culture
X Report 14 Jul 2025
SpaceX successfully launched the Dror 1 satellite for Israel Aerospace Industries, marking another step forward in their launch capabilities.
Space Brief 2 Nov 2025
Today's briefing covers India's military communications satellite launch, SpaceX's Starlink mission milestone, Latvia's agreement to the Artemis Accords, and more significant updates in space technology and satellite launches.