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RELAY 2, 737

Orbit data source: Space-Track

RELAY 2, 737 is a payload satellite owned by GSFC (US) that was launched on Tue, 21 Jan 1964 UTC via a THOR DELTA B launch vehicle from the Air Force Eastern Test Range (AFETR). Payload-class satellites include a variety of spacecraft equipped with specific instruments for various scientific and technological missions. These include communications satellites like Starlink; space stations such as the ISS; scientific satellites like the Hubble; Earth observation satellites from companies like Planet Labs, Umbra, and HawkEye 360; GPS; miniature CubeSats for education and research; and military/defense satellites.

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<iframe src="https://www.satcat.com/sats-embedded/737?theme=dark&initialShowStats=false" width="600" height="400" frameborder="0" title="Kayhan Space Satcat Satellite Viewer"></iframe>

Iframe URL

https://www.satcat.com/sats-embedded/737?theme=dark&initialShowStats=false

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ISO8601 Format

Identifier

737, 1964-003A

Orbit

Active

Country

Related business

National Aeronautics and Space Administration (NASA) (US)

Manufacturer

RCA/East Windsor

Mission

Spacecraft

Bus & Motor

RELAY, Unknown motor

Mass

83 kg wet, 83 kg dry

Launch date (UTC)

1964-01-21 (62 years ago)

Launch vehicle

THOR DELTA B

Launch site

Air Force Eastern Test Range (AFETR)

Object type

Payload

Rocket body

Debris

Shape & HBR

Unknown

Radar Cross Section

Medium (>0.1 m² and <1 m²)

Expand to show TLE details & history
Last TLE update: 19 hours ago

TLE from 19 hours ago

0 RELAY 2
1 00737U 64003A   26079.35827833 -.00000010  00000-0  00000-0 0  9995
2 00737  46.4654  85.6362 2602785 281.7046  50.5619  7.39537811679525

Epoch: 2026-03-20T08:35Z

TLE epoch observation values (Epoch: 2026-03-20T08:35:55.247Z)

Latitude

0.00002°

Longitude

138.76154°

Altitude

3,478.915 km

Speed

6.714 km/s

True Right ascension

05h 42m 32s

True Declination

0° 00' 00"

Sunlit

Object was in daylight at epoch

Visualization orbit readout

Latitude

Unknown

Longitude

Unknown

Altitude

Unknown

Speed

Unknown

Apparent Right ascension

Unknown

Apparent Declination

Unknown

Sunlit

N/A

Visualization observer readout

Local Sidereal Time

08:59:04

Azimuth

Unknown

Elevation

Unknown

Doppler factor

Unknown

Orbital elements

Apogee altitude

7,647.783 km

Perigee altitude

1,854.388 km

Semi-major axis

11,129.223 km

Eccentricity

0.26028

Inclination

46.4654°

RAAN

85.6362°

Arg. of periapsis

281.7046°

True anomaly

78.36035°

Mean anomaly

50.5619°

Eccentric anomaly

63.96104°

Mean motion

1.84861 °/min

Orbital period

194.74 mins

BSTAR

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Computing Atmospheric mass density...

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Other satellites on launch #3 in the year 1964 (1964-01-21 UTC)

DELTA 1 R/B, 738

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RELAY 2 Visibility forecast

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Span	Click to sort rows by Start time (UTC) header in descending order	Start Az.	Max El. time (UTC)	Max El. Az.	Max El.	End time (UTC)	End Az.
84 mins	2026-03-21 04:12:46.117Z	243.385° WSW	2026-03-21 04:43:46.117Z	327.846° NNW	44.913°	2026-03-21 05:36:46.117Z	73.692° E
89 mins	2026-03-21 07:49:46.117Z	286.86° WNW	2026-03-21 08:36:46.117Z	24.339° NE	44.89°	2026-03-21 09:18:46.117Z	117.615° SE
72 mins	2026-03-21 11:31:46.117Z	303.026° NW	2026-03-21 12:15:46.117Z	243.051° WSW	36.773°	2026-03-21 12:43:46.117Z	176.595° S
41 mins	2026-03-21 23:34:46.117Z	146.773° SSE	2026-03-21 23:49:46.117Z	103.515° ESE	22.542°	2026-03-22 00:15:46.117Z	61.005° ENE
73 mins	2026-03-22 02:51:46.117Z	223.035° SW	2026-03-22 03:16:46.117Z	139.116° SSE	44.579°	2026-03-22 04:04:46.117Z	63.689° ENE

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Co-orbital & Co-planar RSOs

Thresholds — Semi-major Axis: ±100 km, RAAN: ±3°, Inclination: ±5°
TCA is derived from TLE conjunctions

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CAUTION: Conjunctions in this section are generated from low-fidelity TLE screenings

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Check out RELAY 2, 737 on other resources

View RELAY 2, 737 on NASA - NSSDCA Website

View RELAY 2, 737 on Heavens-Above

View RELAY 2, 737 on Keep Track

View RELAY 2, 737 on Celestrak

View RELAY 2, 737 on Gunter's Space Page

Satcat and Kayhan Space are not affiliated with NASA, Celestrak, Heavens-Above, Keep Track, or Gunter's Space Page.

RELAY 2, 737

Orbit data source: Space-Track

Expand to show TLE details & historyLast TLE update: 19 hours ago

TLE from 19 hours ago

TLE epoch observation values (Epoch: 2026-03-20T08:35:55.247Z)

Visualization orbit readout

Visualization observer readout

Orbital elements

Other satellites on launch #3 in the year 1964 (1964-01-21 UTC)

RELAY 2 Visibility forecast

Co-orbital & Co-planar RSOs

Check out RELAY 2, 737 on other resources

Documentation

Expand to show TLE details & history
Last TLE update: 19 hours ago