Navstar 7

Failed American navigation satellite

Navstar 7Names| GPS I-7
GPS SVN-7

|

Mission type| Navigation
Technology
Operator| U.S. Air Force
Mission duration| 5 years (planned)
Launch failure
Spacecraft properties
Spacecraft| Navstar
Spacecraft type| GPS Block I
Manufacturer| Rockwell Space Systems[1]
Launch mass| 758 kg (1,671 lb) [1]
Dimensions| 5.3 meters of long
Power| 400 watts
Start of mission
Launch date| 19 December 1981, 01:10:00 UTC
Rocket| Atlas E / SGS-1
(Atlas-76E) [2]
Launch site| Vandenberg, SLC-3E
Contractor| Convair
General Dynamics
Entered service| Launch failure
Orbital parameters
Reference system| Geocentric orbit (planned)
Regime| Medium Earth orbit
(Semi-synchronous)
Altitude| 20,200 km
Inclination| 63.0°
Period| 720 minutes

Global Positioning System

<- OPS 5118 (Navstar 6)

OPS 9794 (Navstar 8) ->

Navstar 7, also known as GPS I-7 and GPS SVN-7, was an American navigation satellite which was lost in a launch failure in 1981. It was intended to be used in the Global Positioning System development program. It was the seventh of eleven Block I GPS satellites to be launched, and the only one to fail to achieve orbit.[1]

## Background

[edit]

Global Positioning System (GPS) was developed by the U.S. Department of Defense to provide all-weather round-the-clock navigation capabilities for military ground, sea, and air forces. Since its implementation, GPS has also become an integral asset in numerous civilian applications and industries around the globe, including recreational used (e.g., boating, aircraft, hiking), corporate vehicle fleet tracking, and surveying. GPS employs 24 spacecraft in 20,200 km circular orbits inclined at 55°. These vehicles are placed in 6 orbit planes with four operational satellites in each plane.[3]

## Spacecraft

[edit]

The first eleven spacecraft (GPS Block 1) were used to demonstrate the feasibility of the GPS system. They were 3-axis stabilized, nadir pointing using reaction wheels. Dual solar arrays supplied over 400 watts. They had S-band communications for control and telemetry and Ultra high frequency (UHF) cross-link between spacecraft. They were manufactured by Rockwell Space Systems, were 5.3 meters across with solar panels deployed, and had a design life expectancy of 5 years. Unlike the later operational satellites, GPS Block 1 spacecraft were inclined at 63°.[3]

## Launch

[edit]

Navstar 7 was launched at 01:10 UTC on 19 December 1981, atop an Atlas E launch vehicle with an SGS-1 upper stage. The Atlas used had the serial number 76E, and was originally built as an Atlas E.[2] The launch took place from Space Launch Complex 3E at Vandenberg Air Force Base.[4]

During preparations for launch, a seal on the number B2 engine of the MA-3 booster section of the Atlas was replaced. Sealant from this seeped into three coolant holes, plugging them. Four seconds after liftoff, the engine overheated and burned through its gas generator, severing an oxidiser line. Within seven and a half seconds of launch, the engine lost thrust, causing the rocket to pitch out of control.[5] It was destroyed by range safety officer,[6] with debris landing within 150 m (490 ft) of the launch pad, less than twenty seconds after liftoff.[5]

## Mission

[edit]

If the launch had been successful, it would have placed Navstar 7 into a transfer orbit, from which the satellite would have raised itself into medium Earth orbit by means of a Star-27 apogee motor.[1] The spacecraft had a design life of 5 years and a mass of 758 kg (1,671 lb).[1]

## References

[edit]

1. ^ a b c d e Krebs, Gunter. "GPS (Navstar)". Gunter's Space Page. Retrieved 12 July 2012.
2. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Report. Retrieved 12 July 2012.
3. ^ a b "Display: Navstar 6 1980-032A". NASA. 14 May 2020. Retrieved 21 November 2020. This article incorporates text from this source, which is in the public domain.
4. ^ McDowell, Jonathan. "Launch List". Launch Vehicle Database. Jonathan's Space Report. Archived from the original on 15 August 2020. Retrieved 12 July 2012.
5. ^ a b Eleazer, Wayne (31 January 2011). "Launch failures: the "Oops!" factor". The Space Review. Retrieved 12 July 2012.
6. ^ "Booster Destroyed on Liftoff". The Press-Courier. Vol. 45, no. 159\. Oxnard, California. 19 December 1981. p. 3.

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NAVSTAR Global Positioning System satellites

List of GPS satellites

Block I|

* 1
* 2
* 3
* 4
* 5
* 6
* 7†
* 8
* 9
* 10
* 11

Block II|

* 1
* 2
* 3
* 4
* 5
* 6
* 7
* 8
* 9

Block IIA|

* 1
* 2
* 3
* 4
* 5
* 6
* 7
* 8
* 9
* 10
* 11
* 12
* 13
* 14
* 15
* 16
* 17
* 18
* 19

Block IIR|

* 1†
* 2
* 3
* 4
* 5
* 6
* 7
* 8
* 9
* 10
* 11
* 12
* 13
* 14
* 15
* 16
* 17
* 18
* 19
* 20
* 21

Block IIRM|

* 1
* 2
* 3
* 4
* 5
* 6
* 7
* 8

Block IIF|

* 1
* 2
* 3
* 4
* 5
* 6
* 7
* 8
* 9
* 10
* 11
* 12

Block III|

* 01
* 02
* 03
* 04
* 05
* 06
* 07
* 08
* 09
* 10

Block IIIF|

* 11
* 12
* 13
* 14
* 15
* 16
* 17
* 18
* 19
* 20

Italics indicate future missions. Signs † indicate launch failures.

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← 1980

Orbital launches in 1981

1982 →

* Kosmos 1237
* Molniya-3 No.25
* Kosmos 1238
* Kosmos 1239
* Kosmos 1240
* Kosmos 1241
* Musson No.11
* Progress 12
* Kosmos 1242
* Molniya 1-49
* Kosmos 1243
* Interkosmos 21
* Kiku 3
* Kosmos 1244
* Kosmos 1245
* Kosmos 1246
* Kosmos 1247
* Hinotori
* Comstar D4
* OPS 1166
* Kosmos 1248
* Kosmos 1249
* Kosmos 1250
* Kosmos 1251
* Kosmos 1252
* Kosmos 1253
* Kosmos 1254
* Kosmos 1255
* Kosmos 1256
* Kosmos 1257
* Soyuz T-4
* Kosmos 1258
* OPS 7350
* Kosmos 1259
* Gran' No.18L
* Kosmos 1260
* Soyuz 39
* Molniya-3 No.24
* Yantar-2K No.979
* Kosmos 1261
* Kosmos 1262
* Kosmos 1263
* STS-1
* Kosmos 1264
* Kosmos 1265
* Kosmos 1266
* OPS 7225
* Kosmos 1267
* Kosmos 1268
* Kosmos 1269
* Soyuz 40
* Meteor-2 No.8
* Nova-1
* Kosmos 1270
* Kosmos 1271
* Kosmos 1272
* Kosmos 1273
* GOES 5
* Intelsat V F-1
* Rohini RS-D1
* Kosmos 1274
* Kosmos 1275
* Molniya-3 No.30
* Kosmos 1276
* Kosmos 1277
* Meteosat 2
* APPLE
* CAT-3
* Kosmos 1278
* NOAA-7
* Molniya 1-50
* Ekran No.21L
* Kosmos 1279
* Kosmos 1280
* Kosmos 1281
* Meteor-Priroda 2-4
* Iskra 1
* Kosmos 1282
* Kosmos 1283
* Kosmos 1284
* Gran' No.19L
* DE-1
* DE-2
* Kosmos 1285
* Kosmos 1286
* FLTSATCOM 5
* Kosmos 1287
* Kosmos 1288
* Kosmos 1289
* Kosmos 1290
* Kosmos 1291
* Kosmos 1292
* Kosmos 1293
* Kosmos 1294
* Bulgaria 1300
* Himawari 2
* Kosmos 1295
* Kosmos 1296
* Kosmos 1297
* Kosmos 1298
* Kosmos 1299
* Kosmos 1300
* Kosmos 1301
* Kosmos 1302
* OPS 3984
* Kosmos 1303
* Kosmos 1304
* Kosmos 1305
* Kosmos 1306
* Kosmos 1307
* Kosmos 1308
* Kosmos 1309
* Shijian 2
* Shijian 2-01
* Shijian 2-02
* Oreol 3
* Kosmos 1310
* SBS 2
* Kosmos 1311
* Kosmos 1312
* Kosmos 1313
* SME
* UoSAT-1
* Kosmos 1314
* Gran' No.20L
* Kosmos 1315
* Kosmos 1316
* Molniya-3 No.31
* Venera 13
* OPS 4029
* Kosmos 1317
* Kosmos 1318
* Venera 14
* STS-2
* Kosmos 1319
* Molniya 1-51
* Satcom 3R
* Bhaskara 2
* Kosmos 1320
* Kosmos 1321
* Kosmos 1322
* Kosmos 1323
* Kosmos 1324
* Kosmos 1325
* Kosmos 1326
* Kosmos 1327
* Kosmos 1328
* Kosmos 1329
* Intelsat V F-3
* RS-3
* RS-4
* RS-5
* RS-6
* RS-7
* RS-8
* Navstar 7
* Kosmos 1330
* MARECS-1
* CAT-4
* Molniya-1 No.55

Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).
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