Bangladesh Satellite-1: build a communications service

Bangladesh Satellite-1 is the name used by its operator, Bangladesh Satellite Company Limited, or BSCL. Launch-era material calls the same spacecraft Bangabandhu Satellite-1; the archive retains Bangabandhu 1 as its catalog title. It launched in May 2018. This was Bangladesh’s first geostationary communications satellite, a different milestone from BRAC Onnesha’s earlier university CubeSat mission.

Thales Alenia Space designed and supplied the satellite and two ground segments. Its payload has twenty-six Ku-band and fourteen C-band transponders, consistent with BSCL’s forty-transponder — open definition description. The communications role includes broadcasting and links for networks and broadband services. A transponder receives and retransmits radio signals; it does not automatically turn every location under a beam into a connected customer.

A coverage map indicates where a beam is intended to serve terminals under stated conditions. A user still needs suitable equipment, power and a working connection onward to the intended service. BSCL’s remote and coastal connectivity project describes this ground infrastructure, including support during the 2022 floods. A satellite link can help where terrestrial connections are difficult, but the local terminal and network remain part of the service.

Radio bandwidth is measured in hertz, while a data rate is measured in bits per second. They are related through the signal scheme and operating conditions, not interchangeable units. In an invented example, a 10-megahertz allocation carries two useful bits per second per hertz, giving 20 megabits per second. If a different setup achieves only one useful bit per second per hertz, the same bandwidth carries 10 megabits per second. These are teaching assumptions, not BSCL service specifications.

Keep bandwidth and throughput distinct

Imagine a school terminal can receive 20 megabits per second but the school’s local network forwards only 8. Under these assumptions, a student cannot receive a sustained 20-megabit-per-second transfer through that path. Increasing satellite capacity alone does not remove the local bottleneck. Testing at the application endpoint reveals limitations that a measurement at the satellite terminal can miss.

Operations also distinguish commanding and monitoring the spacecraft from delivering each customer’s service. A backup ground facility is valuable only if its handover procedure, equipment and connections work when needed. BSCL gives a fifteen-year mission duration for the spacecraft; that is a design description rather than a guarantee of every future service interval. The meaningful outcome is a verified communications path, with its capacity and availability measured under identified conditions.