Blue Scout Junior Credit - via Peter Alway

Smaller Air Force version of Scout used for suborbital military tests.

Historical Essay © Andreas Parsch

Ford RM-91 Blue Scout Junior

The XRM-91 Blue Scout Junior (sometimes called Journeyman B) was a rocket of the U.S. Air Force's System 609A Blue Scout family (for general information on Blue Scout, see article on RM-89 Blue Scout I). The XRM-91 did not resemble the other Scout variants externally, because the usual first Scout stage (an Aerojet General Algol) was not used. Instead, the four-stage Blue Scout Junior used Scout's 2nd and 3rd stages (Castor and Antares) as the first two stages, and added an Aerojet General Alcor and a spherical NOTS Cetus in a common nose fairing. The XRM-91 also lacked the gyro-stabilization and guidance system of the RM-89 Blue Scout I and RM-90 Blue Scout II, making it a completely unguided rocket. It relied on second-stage fins and two spin motors to achieve a stable flight trajectory.

The first launch of an XRM-91 occurred on 21 September 1960, making it actually the first Blue Scout configuration to fly. The flight was planned to make radiation and magnetic field measurements at distances of up to 26700 km (16600 miles) from earth, and while the rocket did indeed achieve this altitude, the telemetry system failed so that no data was received. The second launch in November ended with a failure during second stage burn. The third flight was to measure particle densities in the Van Allen belts and reached a distance of 225000 km (140000 miles), but again a telemetry failure prevented the reception of scientific data. The fourth and final XRM-91 mission in December 1961 also carried particle detectors, and was the only completely successful flight of the initial Blue Scout Junior program. The Blue Scout Junior would have been easily powerful enough to put a small satellite in low-earth orbit but was never used to do so.

The Blue Scout Junior was regarded by the USAF as the most useful of the various Blue Scout configurations. It was used (in slightly modified form) between 1962 and 1965 by the Air Force as the SLV-1B/C launch vehicle for suborbital scientific payloads. The SLV-1C was also chosen as the rocket for the MER-6A interim ERCS (Emergency Rocket Communications System) vehicle. The NASA used a three-stage Blue Scout Junior configuration (omitting the Cetus 4th stage) as the RAM B.

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for XRM-91:

[1] Peter Alway: "Rockets of the World, 2000 Supplement", Saturn Press, 2000
[2] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
[3] Mark Wade: Encyclopedia Astronautica

Manufacturer: Vought. Launches: 31. Failures: 4. Success Rate: 87.10%. First Launch Date: 1960-09-21. Last Launch Date: 1978-12-05. Launch data is: complete. Payload: 10 kg (22 lb). to a: 26.775 km altitude, 11,290 km range trajectory. Apogee: 1,000 km (600 mi). Liftoff Thrust: 222.400 kN (49,998 lbf). Total Mass: 5,797 kg (12,780 lb). Core Diameter: 0.79 m (2.59 ft). Total Length: 14.00 m (45.00 ft).

4 stage vehicle consisting of 1 x Castor + 1 x Antares + 1 x Alcor + 1 x Cetus

Apogee: 200,000 km (120,000 mi). Liftoff Thrust: 222.000 kN (49,907 lbf). Total Mass: 5,800 kg (12,700 lb). Core Diameter: 0.79 m (2.59 ft). Total Length: 12.40 m (40.60 ft).

3 stage version consisting of 1 x Castor + 1 x Antares + 1 x Alcor

Apogee: 1,000 km (600 mi). Liftoff Thrust: 222.000 kN (49,907 lbf). Total Mass: 5,800 kg (12,700 lb). Total Length: 12.00 m (39.00 ft).

Single stage version consisting of 1 x Castor

Apogee: 300 km (180 mi). Liftoff Thrust: 235.000 kN (52,830 lbf). Total Length: 8.00 m (26.20 ft).

2 stage vehicle version of 2 x Recruit + 1 x Castor

Apogee: 240 km (140 mi). Liftoff Thrust: 586.000 kN (131,738 lbf). Total Mass: 5,200 kg (11,400 lb). Total Length: 10.00 m (32.00 ft).

• Stage Number: 1. 1 x Stage: Castor 2. Gross Mass: 4,424 kg (9,753 lb). Empty Mass: 695 kg (1,532 lb). Thrust (vac): 258.915 kN (58,206 lbf). Isp: 262 sec. Burn time: 37 sec. Isp(sl): 232 sec. Diameter: 0.79 m (2.59 ft). Span: 0.79 m (2.59 ft). Length: 6.04 m (19.81 ft). Propellants: Solid. No Engines: 1. Engine: TX-354-3.

• Stage Number: 2. 1 x Stage: Antares 1A. Gross Mass: 1,225 kg (2,700 lb). Empty Mass: 294 kg (648 lb). Thrust (vac): 60.497 kN (13,600 lbf). Isp: 256 sec. Burn time: 39 sec. Isp(sl): 233 sec. Diameter: 0.78 m (2.55 ft). Span: 0.78 m (2.55 ft). Length: 3.38 m (11.08 ft). Propellants: Solid. No Engines: 1. Engine: X-254.

• Stage Number: 3. 1 x Stage: Alcor. Gross Mass: 520 kg (1,140 lb). Empty Mass: 50 kg (110 lb). Thrust (vac): 35.588 kN (8,001 lbf). Isp: 230 sec. Burn time: 30 sec. Diameter: 0.46 m (1.50 ft). Span: 0.46 m (1.50 ft). Length: 1.37 m (4.49 ft). Propellants: Solid. No Engines: 1. Engine: Alcor. Masses, specific impulse estimated.

• Stage Number: 4. 1 x Stage: Cetus. Gross Mass: 50 kg (110 lb). Empty Mass: 10 kg (22 lb). Thrust (vac): 4.001 kN (899 lbf). Isp: 230 sec. Burn time: 20 sec. Diameter: 0.43 m (1.41 ft). Span: 0.43 m (1.41 ft). Length: 0.51 m (1.67 ft). Propellants: Solid. No Engines: 1. Engine: NOTS 100A. Masses, specific impulse estimated.

1960 September 21 - 13:02 GMT - Launch Site: Cape Canaveral. Launch Complex: LC18. Launch Pad: LC18A. Launch Vehicle: Blue Scout Junior. Model: Blue Scout Jr. LV Configuration: Blue Scout Jr D-1.

• Blue Scout first launch, with Radiation Probe (HETS) payload. Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 26,700 km (16,500 mi). COSPAR: 19600921PS. Decay Date: 1960-09-21. USAF Blue Scout rocket fired from Cape Canaveral placed instrumented payload 16,600 miles above the earth, the first of 11 such tests, but no data were received due to radio malfunction. References: 0.

• HETS Magnetospheric mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 200 km (120 mi). References: 5, 126, 799.

• HETS Radiation Probe Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 225,000 km (139,000 mi). COSPAR: 19610817S. Decay Date: 1961-08-17. Suborbital. References: 5.

• Radiation Probe Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 44,400 km (27,500 mi). COSPAR: 19611204S. Decay Date: 1961-12-04. References: 0.

• ERCS/279L 1 Communications mission Nation: USA. Class: Technology. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• ERCS/279L 2 Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• ERCS/279L 3 Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• Ion Engine Test A Technology mission Nation: USA. Payload: 661A Flight 21-1. Class: Technology. Type: Ion engine. Spacecraft: Program 661A. Agency: USAF. Apogee: 2,000 km (1,200 mi). When the high-voltage power supplies were first turned-on, intermittent high-voltage breakdowns occurred, and the beam power supply became inoperative. Post-flight examination of the power supply indicated the high-voltage breakdowns were probably caused by pressure buildup in the primary propulsion unit due to gas vented from the spacecraft batteries. The primary propulsion unit high voltage section was not adequately vented to keep the pressure low enough. Engine thrusting was not accomplished in this test.References: 5, 1169.

• ERCS 279L Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• ERCS 279L Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• ERCS 279L Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• Space Radio Project (OAR 22-1/AFCRL-1/21) Nation: USA. Class: Technology. Agency: USAF. Apogee: 13,862 km (8,613 mi). Decay Date: 1963-07-30. References: 0.

• ERCS 279L Communications mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 1,000 km (600 mi). References: 5, 917.

• OAR 22-2/AFCRL-9 Magnetospheric mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 600 km (370 mi). References: 5, 1716.

• Ion Engine Test B Technology mission Nation: USA. Payload: 661A Flight 21-2. Class: Technology. Type: Ion engine. Spacecraft: Program 661A. Agency: USAF. Apogee: 2,000 km (1,200 mi). The launch was designed to provide about 30 minutes of flight above an altitude of 370 km. At seven minutes into the flight the engine was operated with ion beam extraction. Full beam current of 94 mA was achieved about 10 minutes later. During the course of engine operation, an electric field strength meter was used to infer payload floating potential relative to space. Spacecraft potential was about 1000 V negative during most of the engine operation with the filament neutralizer. The absolute value of payload potential was about ten times higher than anticipated, and it was suspected that there was inadequate neutralization of the ion beam. The contact ion engine operated for 19 minutes until spacecraft reentry into the atmosphere. In addition to withstanding the environmental rigors of space flight, the ion propulsion system demonstrated electromagnetic compatibility with other spacecraft subsystems and the ability to regulate and control a desired thrust level.References: 5, 917.

• Ion Engine Test C Technology mission Nation: USA. Payload: 661A Flight 21-3. Class: Technology. Type: Ion engine. Spacecraft: Program 661A. Agency: USAF. Apogee: 500 km (310 mi). In this test, an additional wire neutralizer was incorporated and was immersed in the ion beam to provide a higher probability of adequate neutralization. The contact ion engine only achieved about 20% of full-thrust before reentry into the atmosphere. The short test time was due to a very short burn of the Scout vehicle's third stage. The high voltage was applied to the engine 7 minutes into the flight when the altitude was 490 km. Engine operation ended after 4 minutes when the altitude was only 80 km.References: 5, 1169.

• OAR 22-3/AFCRL-309 Magnetospheric mission Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 200 km (120 mi). References: 5, 126, 1592.

• Magnetosphere Probe (OAR 22-4/AFCRL-35) Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 12,067 km (7,498 mi). Decay Date: 1965-03-30. References: 0.

• Radiation Effects (OAR 22-9/AFWL-14) Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 25,422 km (15,796 mi). Decay Date: 1965-04-09. References: 0.

• Magnetosphere Probe (OAR 22-8/AFCRL-335) Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 13,586 km (8,441 mi). Decay Date: 1965-05-12. References: 0.

• Radiation Effects (OAR 22-5/AFWL-304) Nation: USA. Class: Earth. Type: Magnetosphere. Agency: USAF. Apogee: 17,533 km (10,894 mi). Decay Date: 1965-06-09. References: 0.

• Marquardt Scramjet Technology mission Nation: USA. Class: Technology. Type: Scramjet. Agency: USAF AFSC. Apogee: 54 km (33 mi). References: 5, 916.

• SPED II re-entry vehicle test flight Nation: USA. Agency: NASA. Apogee: 85 km (52 mi). References: 1756.

• NRL NB22.208 Ultraviolet Astronomy mission Nation: USA. Class: Astronomy. Agency: USN. Apogee: 1,480 km (910 mi). References: 5, 1722.

• Ionosphere mission Nation: USA. Apogee: 406 km (252 mi). References: 1592.

• Re-entry Vehicle Test mission Nation: USA. Agency: USAF. Apogee: 200 km (120 mi). References: 1836.

• EXCEDE Active Plasma mission Nation: USA. Agency: USAF. Apogee: 100 km (60 mi). References: 1592.

• Technology mission Nation: USA. Agency: USAF. Apogee: 200 km (120 mi). References: 1836.

• Technology mission Nation: USA. Agency: USAF. Apogee: 200 km (120 mi). References: 1836.

• Technology mission Nation: USA. Agency: USAF. Apogee: 200 km (120 mi). References: 1836.

• DOT 1 Interceptor mission Nation: USA. Agency: USAF. Apogee: 235 km (146 mi). References: 1836.

• McDowell, Jonathan, Jonathan's Space Home Page, Harvard University, 1997-present. Jonathan McDowell's complete on-line listing of all objects orbited and over 20,000 rocket launches Accessed at: http://www.planet4589.org/jsr.html.

• Koelle, Heinz Hermann,, Handbook of Astronautical Engineering, McGraw-Hill,New York, 1961. The only such comprehensive handbook ever produced, and at the dawn of the space age.

• Gatland, Kenneth, Spacecraft and Boosters, Iliffe Books. London, 1964. Survey of world launch vehicles.

• Parsch, Andreas, DesignationSystems.Net, . Outstanding, unique reference for aircraft, missiles, propulsion, and avionics systems. Accessed at: http://www.designation-systems.net/.