The Delta N or Thor-Delta N was an American

expendable launch system An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are either destroyed during reentry or discarded in space. ELVs typically consist of several rocket sta ...

used for nine

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...

al launches between 1968 and 1972. It was a member of the

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...

family of rockets, and the last Delta to be given an alphabetical designation - subsequent rockets were designated using a four digit numerical code. The Delta N consisted of two stages. The first stage was the

Long Tank Thor Long may refer to: Measurement * Long, characteristic of something of great time, duration * Long, characteristic of something of great length * Longitude (abbreviation: long.), a geographic coordinate * Longa (music), note value in early music ...

, a stretched version of the

Thor Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding æsir, god associated with lightning, thunder, storms, sacred trees and groves in Germanic paganism and mythology, sacred groves ...

missile, previously flown on the

Delta L The Delta L, Thor-Delta L, or Thrust-Augmented Long Tank Thor-Delta was a US expendable launch system used to launch the Pioneer E and TETR satellites in 1969 (failed) and HEOS satellite in 1972. It was a member of the Delta family of rockets. Th ...

and Delta M. Three

Castor-2 The Castor family of solid-fuel rocket stages and boosters built by Thiokol (now Northrop Grumman) and used on a variety of launch vehicles. They were initially developed as the second-stage motor of the Scout rocket. The design was based on the ...

solid rocket booster A solid rocket booster (SRB) is a large solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and space shuttle, have used SRBs to give ...

s were attached to increase thrust at lift-off. A

Delta E The Delta E, or Thor-Delta E was an American expendable launch system used for twenty-three orbital launches between 1965 and 1971. It was a member of the Delta family of rockets. The first stage was a Thor missile in the DSV-2C configuration, ...

was used as the second stage. If an increased payload capacity was required, six boosters were flown instead of three, in a configuration known as the Delta N6, or "Super Six". Three launches used the N6 configuration. Delta N rockets were launched from Launch Complex 17A at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

, and SLC-2 at

Vandenberg AFB Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from th ...

. There was one failure, the launch of ITOS E on October 21, 1971. The Delta second stage developed an oxidizer leak about 40 seconds into launch so that when its burn began, the engine quickly lost thrust. In addition, the leaking LOX started pushing the stage off its proper flight path. The guidance system tried to compensate by repeatedly firing the attitude control jets, but this resulted in the rapid exhaustion of their propellant and the launch vehicle started tumbling uncontrollably. The ITOS satellite separated on schedule, but was facing in the wrong direction for orbital insertion, so it simply reentered the atmosphere and burned up. The second stage itself and several pieces of debris did manage to reach orbit and remained there for several weeks.

References

Delta (rocket family) {{rocket-stub