Juno I
Encyclopedia
The Juno I was a four-stage American
booster rocket which launched America's first satellite, Explorer 1, in 1958. A member of the Redstone rocket family
, it was derived from the Jupiter-C
sounding rocket
. It is commonly confused with the Juno II
launch vehicle, which was derived from the PGM-19 Jupiter medium-range ballistic missile
.
in 1956 for his proposed Project Orbiter
, obviated the need for a guidance system in the upper stages, proving to be the simplest and most immediate method for putting a payload into orbit; but as it had no upper-stage guidance, it could not inject the payload into a precise orbit. Both the four stage Juno I and three stage Jupiter-C launch vehicles were the same height (21.2 meters), with the added fourth stage booster of the Juno I being enclosed inside the nose cone of the third stage.
and 4
. The American public was happy and relieved that America had finally managed to launch a satellite after the launch failures in the Vanguard
and Viking series. With the relative success of the Juno I program, von Braun developed the Juno II
, using a PGM-19 Jupiter first stage, rather than a Redstone.
The six launches of Juno I were:
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
booster rocket which launched America's first satellite, Explorer 1, in 1958. A member of the Redstone rocket family
Redstone (rocket family)
The Redstone family of rockets consisted of a number of American ballistic missiles, sounding rockets and expendable launch vehicles operational during the 1950s and 60s. The first member of the family was the PGM-11 Redstone missile, from which all other members were derived. The first large U.S...
, it was derived from the Jupiter-C
Jupiter-C
The Jupiter-C was an American sounding rocket used for three sub-orbital spaceflights in 1956 and 1957 to test re-entry nosecones that were later to be deployed on the more advanced PGM-19 Jupiter mobile missile....
sounding rocket
Sounding rocket
A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into...
. It is commonly confused with the Juno II
Juno II
Juno II was an American space launch vehicle used during the late 1950s and early 1960s. It was derived from the Jupiter missile, which was used as the first stage.-Development:...
launch vehicle, which was derived from the PGM-19 Jupiter medium-range ballistic missile
Medium-range ballistic missile
A medium-range ballistic missile , is a type of ballistic missile with medium range, this last classification depending on the standards of certain organizations. Within the U.S. Department of Defense, a medium range missile is defined by having a maximum range of between 1,000 and 3,000 km1...
.
Development
The Juno I consisted of a Jupiter-C rocket, with a fourth stage mounted on top of the "tub" of the third stage, which was fired after third stage burnout to boost the payload and fourth stage to an orbital velocity of 18,000 mph (8 km/s). This multi-stage system, designed by Wernher von BraunWernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...
in 1956 for his proposed Project Orbiter
Project Orbiter
Project Orbiter was a proposed United States spacecraft, an early competitor to Project Vanguard. It was jointly run by the United States Army and United States Navy. It was ultimately rejected by the Ad Hoc Committee on Special Capabilities, which selected Project Vanguard instead...
, obviated the need for a guidance system in the upper stages, proving to be the simplest and most immediate method for putting a payload into orbit; but as it had no upper-stage guidance, it could not inject the payload into a precise orbit. Both the four stage Juno I and three stage Jupiter-C launch vehicles were the same height (21.2 meters), with the added fourth stage booster of the Juno I being enclosed inside the nose cone of the third stage.
History
Although Juno I's Explorer 1 launch was a huge success for the U.S., only two of its remaining five flights were successful; launching Explorer 3Explorer 3
Explorer 3 was an artificial satellite of the Earth, nearly identical to the first United States artificial satellite Explorer 1 in its design and mission...
and 4
Explorer 4
Explorer 4 was a US satellite launched on July 26, 1958. It was instrumented by Dr. James van Allen's group. The Department of Defense's Advanced Research Projects Agency had initially planned two satellites for the purposes of studying the Van Allen radiation belts and the effects of nuclear...
. The American public was happy and relieved that America had finally managed to launch a satellite after the launch failures in the Vanguard
Project Vanguard
Project Vanguard was a program managed by the United States Naval Research Laboratory , which intended to launch the first artificial satellite into Earth orbit using a Vanguard rocket as the launch vehicle from Cape Canaveral Missile Annex, Florida....
and Viking series. With the relative success of the Juno I program, von Braun developed the Juno II
Juno II
Juno II was an American space launch vehicle used during the late 1950s and early 1960s. It was derived from the Jupiter missile, which was used as the first stage.-Development:...
, using a PGM-19 Jupiter first stage, rather than a Redstone.
The six launches of Juno I were:
- January 31, 1958: orbited Explorer 1 weighing 30.66 lb (13.91 kg) with 18.35 lb (8.32 kg) of payload, perigee 224 mi (360 km), apogee 1,575 mi (2,535 km). Explorer 1 ceased transmission of data on May 23, 1958 when its batteries died, but remained in orbit for more than 12 years. It made a fiery reentry over the Pacific Ocean on March 31, 1970.
- March 5, 1958: attempted orbit of Explorer 2Explorer 2Explorer 2 was to be a repeat of the Explorer 1 mission. However, due to a failure in the rocket during launch, the spacecraft did not reach orbit....
, weighing 31.36 lb (14.22 kg) with 18.83 lb (8.54 kg) of payload, failed because fourth stage did not ignite.
- March 26, 1958: orbited Explorer 3Explorer 3Explorer 3 was an artificial satellite of the Earth, nearly identical to the first United States artificial satellite Explorer 1 in its design and mission...
, weighing 31.0 lb (14.0 kg) with 18.53 lb (8.41 kg) of payload, perigee 119 mi (192 km), apogee 1,740 mi (2,800 km). Down June 28, 1958.
- July 26, 1958: orbited Explorer 4Explorer 4Explorer 4 was a US satellite launched on July 26, 1958. It was instrumented by Dr. James van Allen's group. The Department of Defense's Advanced Research Projects Agency had initially planned two satellites for the purposes of studying the Van Allen radiation belts and the effects of nuclear...
, weighing 37.16 lb (16.86 kg) with 25.76 lb (11.68 kg) of payload, perigee 163 mi, apogee 1,373 mi (2,210 km). Down October 23, 1959.
- August 24, 1958: attempted orbit of Explorer 5Explorer 5Explorer 5 was a United States satellite with a weight of 17.24 kg.It launched atop a Jupiter-C rocket on August 24, 1958 from Launch Complex 5, but failed when the rocket's booster collided with its second stage after separation, causing the upper stage firing angle to be off.- References :...
, 37.16 lb (16.86 kg) with 25.76 lb (11.68 kg) of payload. It failed after booster collided with second stage after separation, causing upper stage firing angle to be off.
- October 23, 1958: attempted orbit of 12 ft (3.7 m) inflatable Beacon satellite 31.5 lb (14.3 kg) with 18.3 lb (8.3 kg) of payload. It failed when second stage separated prematurely from booster.