Diamant

by Jean-Jacques Serra
listing by Gunter Krebs

---

Origin: Pierre Précieuses (precious stones) experimental rocket series

The SEREB (Société pour l'Etude et la Réalisation d'Engins Balistiques, firm for the study and developpement of ballistic missiles) was founded in 1959 to support the DMA missile department which was in charge of the French strategic ballistic missile programs SSBS and MSBS. Work begin by a ballistic study program to acquire the technology necessary to development of such missiles. This program achieved several carriers in the Pierre Précieuses series: Agate, Topaze, Emeraude and Saphir.

The VE-110 Agate was the first of the series. It was a 1-stage solid-fuel (Isolane) non piloted carrier of 80 cm diameter. The VE-111 Topaze was similar to Agate but guided by 4 rotative nozzles. The VE-121 Emeraude was 1.40 m diameter; it was the first is the series to use liquid propellant (nitric acid and turpentine). The VE-231 Saphir had 2 stages: Emeraude + Topaze. Saphir enabled in-flight experiments of cap release, stage separation, inertial guidance and reentry.

In December 1961 it was decided to build the Diamant launcher by replacing the payload of Saphir by a third stage. In May 1962 CNES selected DMA to manage the Diamant program, SEREB being the prime contractor. The Rubis rocket was designed to test the third stage in-flight, on top of an Agate stage.

---

Diamant A

The diamant A launcher was made of a 10 m high, 1.4 m diameter Emeraude first stage weighing 14.7 tons. Its Vexin LRBA directional-nozzle motor burned during 93 seconds and delivered 269 kN thrust at sea level (304 kN in vacuum). The second stage was Topaze: 4.7 m high per 80 cm diameter and weighed 2.9 tons. It provided a mean thrust of 156 kN during 44 seconds. The P064 third stage was 2 m high and 65 cm diameter. It weighed 709 kg including 640 kg Isolane (thus its name). It burned for 45 seconds providing 27 to 53 kN thrust. With its cap Diamant was 18.95 m high and weighed 18.4 tons.

Diamant achieved orbiting at first try on 26 Nov 1965. The payload was the simple technological capsule Astérix. After this launch the 3 remaining rockets were used to orbit geodesy satellites (D1 program) between Feb 1966 and Feb 1967. All launches were carried out from the CIEES (Centre InterArmées d'Essais d'Engins Spéciaux, inter-army special machine test center) in Sahara which was closed in July 1967.

Once the Diamant A program ended Rubis was still used as sounding rocket: in July 1967 it delivered an experiment of the Paris-Meudon observatory's space radioastronomy department at 1560 km altitude. The third stage of Diamant A was then used twice as top stage of the Tibère launcher for the Electre experiments between Feb 1971 and Mar 1972.

---

Diamant B

After Diamant numerous projects appear but CNES decides to built a launcher directly derived from Diamant A. The main evolution was the lengthened first stage which used more energy-providing propellants. This first stage called Améthyste was 14.2 m high, 1.4 m diameter, and 20.1 t weight. Its Valois motor delivered 316 kN thrust at sea level (400 kN in vacuum) during 116 seconds. The second stage was identical the Diamant A's one; The top stage (P068) was also enhanced: 1.67 m high, 80 cm diameter and 50 kN thrust during 46s. With its cap (85 cm diameter instead of 65 cm for Diamant A) Diamant B was 23.5 m high and weighed 24.6 tons.

Six Diamant B were ordered: 2 for CNES and 4 for ELDO (in single stage version) which were to be used to test the PAS (Perigee-Apogee System) for Europa 2. Finaly ELDO dropped the idea and the 5 rocket built were used by CNES.

After the launch of the German Wika technological capsule Diamant B launched Peole (technology) and Tournesol ( astronomy). The last 2 launches were failures. All launches occured from the CSG (Centre Spatial Guyanais, Guyana space center) which is operational since April 1968 when the first sounding rocket Veronique was launched from there.

---

Diamant BP4

Development of Diamant BP4 started in Jan 1972. It was based on the first and third stage of its ancestor. The new second stage P4 (Rita) was from the ballistic missile MSBS guided by jet deviation (freon injection). It was 2.28 m long and 1.5 m diamter; it provided a mean 180 kN thrust during 55 seconds. With the 1.38 m cap from the Black Arrow program Diamant BP4 was 21.6 m high and weighed 27 tons.

After 1975 France stopped its sounding rocket and national launcher programs to devote entirely to the european Ariane launcher.

---

Diamant launchers evolution

Designation	First launch	1st stage	2nd stage	3rd stage	300 km	500 km	1000 km
A	1965	Emeraude	Topaze	P064		80
B	1970	Amethyste	Topaze	P068	160	115	25
BP4	1975	Amethyste	Rita	P068	200	153	45

---

Diamant launches

#	Launch id	Payload	Launch Date	Site	Type	Status/Comment
1	65096	Asterix	26 Nov 1965	H	A
2	66013	Diapason	17 Feb 1966	H	A
3	67011	Diadème 1	08 Fab 1967	H	A	Partial failure: orbit too low
4	67014	Diadème 2	15 Feb 1967	H	A
5	70017	A: Dial-Wika B: Mika	10 Mar 1970	K	B
6	70109	Péole	12 Dec 1970	K	B
7	71030	Tournesol	15 Apr 1971	K	B
8	n/a	Polaire	5 Dec 1971	K	B	Failure: 2nd stage failed
9	n/a	Castor Pollux	22 May 1972	K	B	Failure: 3rd stage failed
10	75010	Starlette	6 Feb 1975	K	BP4
11	75039	A: Pollux B: Castor	17 May 1975	K	BP4
12	75092	Aura	27 Sep 1975	K	BP4

Notes: Launch site: H for Hammaguir, Algeria; K for Kourou

---