PARIS — Vietnam’s first Earth observation satellite, VNREDSat-1a, will be launched in April aboard Europe’s new Vega small-satellite launcher under a contract announced Jan. 4 by launch services provider Arianespace.

The satellite is the first of four — two with optical sensors, two with X-band radar instruments — to be launched by 2020 as part of Vietnam’s commitment to develop its Earth observation expertise in addition to its existing domestic satellite telecommunications operator.

As part of a contract with Astrium Satellites, which is building VNREDSat-1a for the Vietnam Academy of Science and Technology (VAST), the 120-kilogram VNREDSat-1a will fly as a secondary payload on Vega’s second mission. Vega’s inaugural flight, a success, occurred in February 2012.

The upcoming launch, one of five that the 20-nation European Space Agency (ESA) has purchased as part of its Vega development program, will carry ESA’s Proba-V Earth observation satellite as the principal payload.

VNREDSat-1a is designed to operate for five years in a sun-synchronous polar orbit at about 670 kilometers in altitude. Its optical sensor is capable of detecting objects as small as 2.5 meters in diameter in black-and-white mode, and 10 meters in color, with an image swath width of 17.5 kilometers.

VNREDSat-1a is being built by Toulouse, France-based Astrium under a contract valued at 55.8 million euros ($73 million) that includes the training of some 15 Vietnamese engineers in Toulouse, the construction in Vietnam of an X-band optical-imagery reception facility and an S-band satellite control center, and the launch of the satellite.

Financed with French Official Development Assistance backing, VNREDSat-1a is part of a long-term development program that VAST says will place Vietnam “into a higher position amongst the countries possessing their own [Earth observation] systems,” according to a December presentation of the program.

The Earth observation program includes optical satellites provided by France and Belgium, and radar satellites to be built in cooperation with Japan, and will follow Vietnam’s successful development of its own satellite telecom operator, Vinasat.

Vinasat’s second satellite, Vinasat-2, built by Lockheed Martin Space Systems and launched aboard Europe’s heavy-lift Ariane 5 rocket in mid-2012, was budgeted at $280 million, including launch. Vietnamese officials have said the satellite, which is expected to operate for at least 15 years and is equipped with 30 Ku-band transponders, should recoup its investment costs within 10 years.

Next up in the Earth observation program is VNREDSat-1b, under construction by a Belgian consortium led by Spacebel. Equipped with an optical sensor, the satellite is scheduled for launch in 2017. This spacecraft will have a similar mass and imaging resolution as the Astrium-built satellite, but with a larger swath width.

Belgian foreign assistance is financing the program, whose total cost including launch is expected to be about 63 million euros, according to VAST.

The scale of Vietnam’s ambitions in Earth observation came into clearer view in late 2011 with an agreement with Japanese manufacturers and the Japanese government to build two high-resolution radar Earth observation satellites and the associated ground infrastructure.

VAST estimates that the radar satellite program, called LOTUSat, will cost some 54.4 billion Japanese yen, or about $620 million, between 2012 and 2020, a figure that includes the two satellites’ construction and launch. LOTUSat-1, to be built by NEC Corp. of Tokyo, is expected to weigh less than 500 kilograms and to carry X-band synthetic aperture radar sensors with a 1-meter resolution at nadir.

LOTUSat-1 will be assembled in Japan and launched in 2017, according to VAST. LOTUSat-2, to have a similar image-taking capability, will be assembled, integrated and tested at a new production facility being built as part of the program at the Hoa Lac technology campus near Hanoi, with a launch expected in 2020.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.