Encyclopedia Astronautica
Exos



exos.jpg
Exos
American sounding rocket. Three stage vehicle consisting of 1 x M-6 + 1 x Nike + 1 x Recruit

The Exos sounding rocket was developed by the University of Michigan under a contract from the Air Force Cambridge Research Center. The three fins of the Nike booster had to be replaced by four new clipped-delta fins. First flight test of an all-up Exos rocket occurred in June 1958. Exos was zero-launched from a rail launcher.

Failures: 1. Success Rate: 90.00%. First Fail Date: 1960-02-19. Last Fail Date: 1960-02-19. Launch data is: complete.

Historical Essay © Andreas Parsch

University of Michigan RM-86-PWN-4 Exos

The Exos sounding rocket was developed by the University of Michigan with the assistance of NACA under a contract from the Air Force Cambridge Research Center (AFCRC). It was a three-stage rocket combining an M6 Honest John (see M31-MGR-1A) first stage, an M5 Nike Ajax (see SAM-A-7-MIM-3) second stage and a Thiokol XM19 Recruit as third stage. The three fins of the Nike booster had to be replaced by four new clipped-delta fins. The Exos is very similar, but not identical to the Aerolab Co. Argo C-1, which used the same combination of rockets, but a slightly different aerodynamic design. The first flight test of an all-up Exos rocket occurred in June 1958.

After zero-launch from a specially built rail launcher, the first stage burned for about 4.4 seconds, after which it was separated from the vehicle by aerodynamic drag. After 25 seconds of coasting, the second stage fired for about 3 seconds, followed by separation and almost immediate firing of the third stage for further 1.6 seconds. The third stage and payload nose cone then continued to coast to an apogee of about 480 km (300 miles) (for a 23 kg (50 lb) payload).

In April 1959, the USAF allocated the formal research missile designation XRM-86 to the Exos at the request of the AFCRC, and in June 1963 this designation was changed to PWN-4A. At least eight research flights of XRM-86-PWN-4A vehicles were launched from Eglin AFB between February 1960 and November 1965, mostly with ionosphere research experiments as payload.

Specifications

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

Data for PWN-4A:

Length 12.94 m (42 ft 5.5 in)
Diameter 1st stage: 58.2 cm (22.9 in); 2nd stage: 41.9 cm (16.5 in); 3rd stage: 22.9 cm (9.0 in)
Finspan 1st stage: 2.59 m (8 ft 6 in)
Weight 2660 kg (5870 lb)
Speed 11300 km-h (7040 mph)
Ceiling 480 km (300 miles)
Propulsion 1st stage: Hercules M6 solid-fueled rocket; 404 kN (91000 lb) for 4.4 s
2nd stage: Allegheny Ballistics Lab. X216A2 solid-fueled rocket; 246 kN (55000 lb) for 3 s
3rd stage: Thiokol TE-289 (XM19) Recruit; 167 kN (37600 lb) for 1.6 s
Main Sources

[1] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[2] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
[3] Department of Defense Missile Nomenclature Records
[4] "Sounding Rocket Study of Eighteen Vehicles, Summary Report", NASA, 1961


AKA: PWN-4.
Status: Retired 1965.
Gross mass: 2,600 kg (5,700 lb).
Height: 12.90 m (42.30 ft).
Diameter: 0.58 m (1.90 ft).
Thrust: 365.00 kN (82,055 lbf).
Apogee: 600 km (370 mi).
First Launch: 1958.06.26.
Last Launch: 1965.11.02.
Number: 10 .

More... - Chronology...


Associated Countries
See also
Associated Manufacturers and Agencies
  • Michigan American agency overseeing development of rockets. Univeristy of Michigan, USA. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • Parsch, Andreas, DesignationSystems.Net, Web Address when accessed: here.

Associated Launch Sites
  • Wallops Island Small NASA launch site for sounding rocket launches and occasional Scout launches to orbit. Air launches are conducted from the Drop Zone Wallops Island, 37.00 N 72.0 W. With the last orbital launch in 1985 and the decline in sounding rocket launches, Wallops fell into near-disuse as a launch center. Its fortunes revised with the establishment of Mid-Atlantic Regional Spaceport in 2005 and orbital launches resumed in 2010. More...
  • Eglin This US Air Force proving ground and missile test range, based in Valparaiso, Florida and extending over a vast expanse of the Gulf of Mexico, was founded in 1935, In early 1946 the First Experimental Guided Missiles Group was activated at Eglin. The highly-instrumented Eglin Gulf Test Range supported flight tests of Bomarc, Matador, Quail, and Hound Dog cruise missiles. Both the military and NASA used Eglin to support launch of sounding rockets in support of their programs. Eglin was known to have been used for 441 launches from 1959 to 1980, reaching up to 686 kilometers altitude. The actual number of missile tests was many times greater. More...

Associated Stages
  • HJ Nike Nike-3 Solid propellant rocket stage. Loaded/empty mass 599/256 kg. Thrust 195.60 kN. Vacuum specific impulse 195 seconds. The average sea level thrust of the Nike rocket motor was 190.3 kN. The interstage adapter was bolted to the front of the Nike and consisted of a conical shaped adapter which slip-fit into the second stage nozzle, thus providing for drag separation at Nike burnout. Each Nike fin was 0.45 square meters in area. Normally, the fins were canted to provide a two revolutions per second spin rate at Nike burnout. More...
  • HJ Nike-1 Solid propellant rocket stage. Loaded/empty mass 1,900/954 kg. Thrust 365.00 kN. Rocket motor originally developed for the Army Honest John tactical missile. In sounding rocket applications the interstage adapter was bolted to the front of the Taurus and consisted of a conical shaped adapter which slip-fit into the second stage nozzle, thus providing for drag separation at Taurus burnout. Each Taurus fin was 0.46 square meters in area. Normally, the fins were canted to provide a two revolutions per second spin rate at Taurus burnout. The weight of the booster system is 3005 pounds. More...

Exos Chronology


1958 June 26 - . Launch Site: Wallops Island. Launch Vehicle: Exos.
  • Model 1 test - . Nation: USA. Agency: NASA; AFCRL. Apogee: 370 km (220 mi).

1958 September 25 - . Launch Site: Wallops Island. Launch Vehicle: Exos.
  • Model 2 test - . Nation: USA. Agency: NASA; AFCRL. Apogee: 460 km (280 mi).

1960 February 19 - . 17:18 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AA13.320C. FAILURE: Failure.
  • Chemical release mission - . Nation: USA. Agency: USAF. Apogee: 37 km (22 mi).

1961 August 11 - . 14:30 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AA13.194.
  • Ion density Test / ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 114 km (70 mi).

1962 August 3 - . 17:46 GMT - . Launch Site: Eglin. Launch Vehicle: Exos.
  • Bipolar Probe Ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 365 km (226 mi).

1962 October 25 - . 06:00 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AA13.195.
  • Ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 669 km (415 mi).

1963 July 25 - . 22:38 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AC13.831.
  • Refractive Index Ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 623 km (387 mi).

1965 May 25 - . 23:20 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AD13.815.
  • EM Absorption Ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 488 km (303 mi).

1965 May 26 - . 23:20 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AD13.812.
  • EM Absorption Ionosphere mission - . Nation: USA. Agency: USAF. Apogee: 488 km (303 mi).

1965 November 2 - . 20:00 GMT - . Launch Site: Eglin. Launch Vehicle: Exos. LV Configuration: Exos CRL AE13.559.
  • IQSY 30-kg Sphere Aeronomy mission - . Nation: USA. Agency: USAF. Apogee: 686 km (426 mi).

Home - Browse - Contact
© / Conditions for Use