Explorer 5
 Explorer 5 before launch | |
| Names | Explorer V |
|---|---|
| Mission type | Earth science |
| Operator | JPL / Army Ballistic Missile Agency |
| COSPAR ID | EXPLR5 |
| Mission duration | Failed to orbit |
| Spacecraft properties | |
| Spacecraft | Explorer V |
| Spacecraft type | Science Explorer |
| Bus | Explorer 1 |
| Manufacturer | Jet Propulsion Laboratory |
| Launch mass | 17.43 kg (38.4 lb) |
| Dimensions | Cylinder: 94.6 cm (37.2 in) long, 16.5 cm (6.5 in) in diameter, total length with attached rocket motor: 2.05 m (6 ft 9 in) |
| Start of mission | |
| Launch date | 24 August 1958, 06:17:22 GMT |
| Rocket | Juno I (RS-47) |
| Launch site | Cape Canaveral, LC-5 |
| Contractor | Army Ballistic Missile Agency |
| End of mission | |
| Destroyed | Failed to orbit |
| Orbital parameters | |
| Reference system | Geocentric orbit (planned) |
| Regime | Medium Earth orbit |
| Instruments | |
| Charged Particle Detector | |
Explorer program | |
Explorer 5 was a United States satellite with a mass of 17.43 kg (38.4 lb). It was the last of the original series of Explorer satellites built, designed, and operated by the Jet Propulsion Laboratory.[1]
Background
Explorer 5 was similar in all respects to Explorer 4 and was designed with the same basic science objectives, to make the first detailed measurements of charged particles (protons and electrons) trapped in the terrestrial radiation belts and to observe the effects of the Project Argus A-bomb detonations.[2]
Spacecraft and subsystems
Explorer 5 was a 2.05 m (6 ft 9 in) long, 16.5 cm (6.5 in) diameter cylinder and nosecone that comprised the fourth stage of the Jupiter-C launch vehicle. The on-orbit mass (after fuel burnout) was 17.43 kg (38.4 lb). The spacecraft body was made of stainless AISI-410 steel, 0.058 cm (0.023 in) thick. The surface was sandblasted, no aluminum oxide striping was used as on earlier Explorer satellites.[2]
The base of the cylinder held the Sergeant solid-fuel rocket motor. The Mallory mercury batteries for the low power transmitter were in the upper part of the nose cone. Below these was the low power (10 mW, 108.00 MHz) transmitter for the carrier and sub-carrier signals, which used the stainless steel nose cone as an antenna.[2]
Below the nose cone was the detector deck, holding the instrumentation for the radiation experiments, the command receiver, for interrogations, high power playback transmitter (25-30 mW, 108.03 MHz) for interrogation response, cosmic ray experiment electronics, and Mallory mercury batteries for the high power transmitter. The lower spacecraft body was used as the antenna for the high power transmitter. A heat radiation shield was mounted between the payload and the rocket motor. Temperature gauges were mounted at various locations in the spacecraft.[2]
The radiation experiment comprised four detectors, two Geiger counters and two scintillation counters. One of the Geiger-Mueller counters was unshielded and one was shielded with 1.6 g/cm2 lead to screen out lower energy particles and radiation. One scintillator was a Cesium (CsI) crystal with a 0.8 mg/cm2 nickel foil window, the other was a plastic scintillator with a 0.14 g/cm2 aluminum window. All radiation experiments were within the spacecraft wall, which provided a protection of 1.2 g/cm2 iron.[2]
Juno I launch vehicle
The launch vehicle was a Juno I, a variant of the three-stage Jupiter-C with an added fourth propulsive stage, which in this case was the Explorer 4. The first stage was an upgraded Redstone liquid-fueled rocket. The second stage comprised a cluster of eleven Sergeant solid-fuel rocket motors and the third stage held three Sergeants. The booster was equipped to spin the fourth stage in increments, leading to a final rate of 750 rpm about its long axis.[2]
Instrument
Charged Particle Detector
The purpose of this experiment was to extend the first measurements of the trapped radiation belt discovered with
Mission
Explorer 5 launched on 24 August 1958 at 06:17:22 GMT from the Cape Canaveral Missile Test Center of the Atlantic Missile Range. The spacecraft was not oriented correctly when the second stage fired about 3 minutes after liftoff, preventing it from achieving orbit.[2]
Launch
It launched atop a Juno I launch vehicle on 24 August 1958 from
See also
- Explorer program
- Operation Argus
References
- ^ "Explorer 5". Jet Propulsion Laboratory. 2021. Retrieved 12 November 2021.
This article incorporates text from this source, which is in the public domain.
- ^ a b c d e f g h "Display: Explorer 5 EXPLR5". NASA. 28 October 2021. Retrieved 1 November 2021. This article incorporates text from this source, which is in the public domain.
- ^ "Experiment: Charged Particle Detector". NASA. 28 October 2021. Retrieved 1 November 2021. This article incorporates text from this source, which is in the public domain.
- ^ "Past Missions - Explorer 1-5". Jet Propulsion Laboratory. Retrieved 1 November 2021. This article incorporates text from this source, which is in the public domain.
.png){kind=spacer}