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SERT 2

SERT II, launched in 1970, was an important technology mission for electric propulsion. It operated ion thrusters in space for extended periods and helped demonstrate that low-thrust propulsion could work reliably far longer than a chemical rocket burn.

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Object identity

NORAD ID
04327
COSPAR ID
1970-009A
Operator
Not listed
Country
Not listed
Launch date
Not listed

Immediate discovery

Why this satellite matters

Electric propulsion is a mathematics lesson in patience: tiny thrust applied for a very long time can create a large cumulative change in velocity, or delta-v, while using propellant efficiently.

Understanding the mission

Science and engineering ideas

Electric propulsion is a mathematics lesson in patience: tiny thrust applied for a very long time can create a large cumulative change in velocity, or delta-v, while using propellant efficiently.

Mission

Mission and purpose

The current public orbital catalog identifies this object, but verified mission-specific information may be limited. TransitSatellite will expand this page when authoritative information is available.

  • Electric propulsion is a mathematics lesson in patience: tiny thrust applied for a very long time can create a large cumulative change in velocity, or delta-v, while using propellant efficiently.

Design

Engineering

Electric propulsion is a mathematics lesson in patience: tiny thrust applied for a very long time can create a large cumulative change in velocity, or delta-v, while using propellant efficiently.

Real orbital values

The mathematics

The current two-line element set reports approximately 13.5875 revolutions per day. Dividing 1,440 minutes by that value gives an estimated orbital period of 106 minutes.

Period

106 min

Representative speed

26,389 km/h

Representative altitude

1,047 km

Inclination

99.29°

These are representative calculations derived from current orbital elements, not fixed physical specifications. Altitude and speed change around an elliptical orbit, and predictions change as new orbital elements are published.

Launch record

Launch and deployment

SERT II launched on 3 February 1970 aboard a Thorad-Agena from Vandenberg.

TransitSatellite does not estimate historical launch weather. Temperature, clouds, wind, holds, and scrub reasons will appear only when supported by traceable historical sources.

Orbit

LEO orbit explained

Low Earth orbit is the region closest to Earth used by most crewed spacecraft, many science missions, Earth-observation satellites, and large constellations. Objects move quickly and commonly complete an orbit in roughly 90 to 130 minutes.

LEO can provide detailed Earth views, lower communications delay, and easier access than higher orbits, but it covers less area per spacecraft and is more affected by atmospheric drag.

Live TransitSatellite experience

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Learning

Questions to explore

  • What can an orbit tell us before the mission is fully identified?
  • Why are stable catalog identifiers important?

Evidence

Sources and data notes

Current identity and orbital elements come from CelesTrak’s public GP data. Calculated orbit values are derived from the current TLE and may change after catalog updates. Mission-history claims are added separately and require authoritative sources.

Catalog updated

Sep 17, 2026, 8:52 AM UTC

Story review

1970-01-01T00:00:00.000Z