# Interstellar Boundary Explorer

> NASA satellite

**Wikidata**: [Q835898](https://www.wikidata.org/wiki/Q835898)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Interstellar_Boundary_Explorer)  
**Source**: https://4ort.xyz/entity/interstellar-boundary-explorer

## Summary
Interstellar Boundary Explorer (IBEX) is a NASA research satellite in the Small Explorer program operated and manufactured by the Southwest Research Institute. It was launched on 2008-10-19 on a Pegasus (F40) air-launched rocket and entered service in January 2009.

## Key Facts
- Interstellar Boundary Explorer (IBEX) is a NASA research satellite and an artificial satellite of the Earth.  
- Launch date: 2008-10-19 at 17:47:23 (COSPAR ID 2008-051A; NSSDCA ID 2008-051A).  
- Operator and primary manufacturer: Southwest Research Institute; Orbital Sciences Corporation served as a subcontractor for the spacecraft bus.  
- Launch vehicle and start point: Pegasus (F40) air-launched rocket, deployed from the Stargazer mother ship at Bucholz Army Airfield (Kwajalein Atoll).  
- Mass: launch weight 107 kg (documented launch weight) and dry mass 80 kg.  
- Spacecraft bus: Star Bus (MicroStar-2); space tug / booster: Star 27.  
- Dimensions: height 58 cm; diameter 95 cm.  
- Orbit (epoch 2022-01-19): high Earth orbit with semi-major axis 195,580 km, apoapsis 288,819 km, periapsis 89,584 km, orbital inclination 44.9273°, orbital eccentricity 0.5093472, and orbital period 860,795.75 s.  
- Principal investigator: David McComas.  
- Capital cost (space mission, 2008): USD 169,000,000.  
- Service entry: 2009-01 (entered operational service).

## FAQs
### Q: What is the Interstellar Boundary Explorer (IBEX)?
A: IBEX is a NASA research satellite in the Small Explorer program operated by the Southwest Research Institute. It was launched on 2008-10-19 and entered service in January 2009.

### Q: Who built and operates IBEX?
A: The Southwest Research Institute is listed as the operator and general contractor/manufacturer, with Orbital Sciences Corporation as a subcontractor for the spacecraft bus.

### Q: When and how was IBEX launched?
A: IBEX was launched on 2008-10-19 by a Pegasus air-launched rocket (F40) carried aloft by the Stargazer aircraft and released near Bucholz Army Airfield (Kwajalein Atoll).

### Q: What are IBEX’s basic physical and orbit characteristics?
A: IBEX has a launch mass of about 107 kg (dry mass ~80 kg), measures roughly 58 cm in height and 95 cm in diameter, and operates in a high, eccentric Earth orbit (apoapsis ~288,819 km, periapsis ~89,584 km; inclination ~44.93°).

### Q: Where can I find official information about IBEX?
A: Official IBEX information is available at https://ibex.princeton.edu/ and NASA’s IBEX page at https://www.nasa.gov/ibex.

## Why It Matters
IBEX is a compact, dedicated research satellite within NASA’s Small Explorer program. As a funded and operated mission by the Southwest Research Institute with a named principal investigator, it represents a focused, mid-cost investment in space science (capital cost ~USD 169 million in 2008). The mission is configured on a small Star Bus (MicroStar-2) platform and launched by an air-launched Pegasus rocket, demonstrating a cost-conscious approach to placing a scientific payload into a high, eccentric Earth orbit. IBEX’s orbital parameters (large semi-major axis and high eccentricity) place it in a high Earth orbit well beyond typical low-Earth missions, enabling mission profiles and measurements distinct from near-Earth satellites. The mission’s listing in official catalogs (COSPAR 2008-051A, NSSDCA 2008-051A, satellite catalog number 33401) and its operation by an experienced non-profit contractor underline its role as an enduring asset in NASA’s portfolio of science missions. Researchers, mission planners, and educators reference IBEX for its engineering choices (small bus, air-launched Pegasus) and its operational model within the Small Explorer series.

## Notable For
- Small, low-mass research satellite design with a documented launch mass of 107 kg and dry mass of 80 kg.  
- Air-launched Pegasus (F40) deployment from the Stargazer aircraft at Bucholz Army Airfield (Kwajalein Atoll).  
- Use of a MicroStar-2 based Star Bus spacecraft bus and Star 27 propulsion/boost element.  
- High-eccentricity high Earth orbit (apoapsis ~288,819 km, periapsis ~89,584 km) with a long orbital period (~860,796 s).  
- Operated and primarily manufactured by the Southwest Research Institute with a defined principal investigator (David McComas).

## Body
### Overview
- Name: Interstellar Boundary Explorer (aliases: IBEX, Explorer 91, SMEX 10, 太阳系边界探测器, Эксплорер-91).  
- Instance: research satellite; artificial satellite of the Earth.  
- Program: part of NASA’s Small Explorer program and the Explorers Program sequence (follows Aeronomy of Ice in the Mesosphere; followed by Wide-field Infrared Survey Explorer and Nuclear Spectroscopic Telescope Array in program listings).

### Launch and Deployment
- Launch date and time: 2008-10-19, 17:47:23 (documented qualifier).  
- Launch vehicle: Pegasus (F40).  
- Launch mode: air-launched from the Stargazer aircraft.  
- Launch site / start point: Bucholz Army Airfield (Kwajalein Atoll).  
- Significant event: rocket launch at Kwajalein Atoll on 2008-10-19.

### Spacecraft and Manufacturing
- Operator and general contractor/manufacturer: Southwest Research Institute.  
- Subcontractor (spacecraft bus): Orbital Sciences Corporation.  
- Spacecraft bus: Star Bus (MicroStar-2).  
- Space tug / kick motor: Star 27.  
- Mass: launch weight 107 kg (preferred), dry weight 80 kg. An additional mass entry (462 kg) is present in the record linked to Star 27.  
- Dimensions: height 58 cm; diameter 95 cm.  
- Power: documented as powered by a spacecraft solar array (detailed qualifier values present in source records).

### Orbit and Trajectory (epoch 2022-01-19)
- Orbit type: high Earth orbit.  
- Semi-major axis: 195,580 km.  
- Apoapsis: 288,819 km.  
- Periapsis: 89,584 km.  
- Orbital inclination: 44.9273°.  
- Orbital eccentricity: 0.5093472.  
- Argument of periapsis: 45.4837°.  
- Mean anomaly: 3.9013°.  
- Orbital period: 860,795.75 seconds.

### Mission Operations and Personnel
- Principal investigator: David McComas.  
- Service entry: January 2009 (service_entry: 2009-01-00).  
- Official websites: https://ibex.princeton.edu/ (preferred) and https://www.nasa.gov/ibex.

### Identifiers and Catalogs
- COSPAR ID: 2008-051A.  
- NSSDCA ID: 2008-051A.  
- Satellite catalog number (SCN): 33401.  
- Wikipedia title: Interstellar Boundary Explorer.  
- Commons category: IBEX.  
- Country of origin: United States.

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## References

1. [Source](https://space.skyrocket.de/doc_sdat/explorer_ibex.htm)
2. Jonathan's Space Report
3. [Source](https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2008-051A)
4. Freebase Data Dumps. 2013
5. [Source](https://www.heavens-above.com/orbit.aspx?satid=33401)
6. [Source](https://www.spaceflightnow.com/pegasus/ibex/)
7. [Source](https://www.nasa.gov/mission_pages/ibex/telecon_20081017.html)