The discussion was part of the Alphasat Hosted Payload workshop, which took place in Lisbon (PO) last week. Close to 80 participants, including members of Europe’s satcom industry, ESA national delegations, space agencies and institutions attended the workshop, which focused on the four hosted payloads that will be launched on board Alphasat. Alphasat, developed in partnership with European operator Inmarsat, is the first satellite to be launched using the new European high-power Alphabus telecommunications platform developed by Astrium and Thales Alenia space under an ESA-CNES cooperation programme.
Workshop attendees took part in sessions that discussed the mission objectives, development programme, technical achievements and exploitation of the hosted payloads on board Alphasat, developed with the support of ESA and national programmes. These include:
Laser communication and Ka-band downlink
The advanced laser communication terminal provides geostationary-orbit to low-Earth-orbit optical communication at 2 Gbps. A Ka-band transmitter sends the data to a ground station.
Q/V-band communication and propagation
A Q/V-band communication repeater explores the use of these frequencies for future applications. In parallel, experiments with the propagation beacon measure the effects of Earth’s atmosphere on radio waves in the Q/V Band.
Star Tracker
A star tracker with active pixel detector is included to gain early flight heritage on this new product. It is capable of very accurate and autonomous attitude acquisition. The sensor is highly resilient to the radiation experienced in geostationary orbits
Environmental testing and radiation sensor
The environment effects facility tests electronic components and solid-state materials in the radiation environment of a geostationary orbit. An energy selective particle spectrometer measures these radiation levels in parallel.
New technologies developed for satellite communications may work during exhaustive testing and in simulations, but it is only when they are working in orbit that these new technologies can be considered a true success. However, launching and operating a dedicated satellite to launch a new service or complement an existing one, is expensive.
Thanks to the hosted or “piggyback” payload concept, new technological advances can be demonstrated in orbit and additional satellite payloads can be operated in a win-win-win situation for operators, industry and public institutions like ESA. Hosted payloads benefit from available capacity on commercial satellites to accommodate additional transponders, instruments, or other applications that have to be operated in space. Partners share the satellite platform. This arrangement takes less time and money to implement, allowing advances in satcom technologies and services and new businesses to grow.
Through its telecommunications programme (ARTES), ESA has supported a number of hosted payloads over the years. These include the launch of the Skyplex processor on the Hot Bird 4 satellite, followed by AmerHis on Amazonas 1.
Recently, ESA issued a special Call for Interest offering the possibility of combining a hosted payload in conjunction with the larger, more complex payloads of the European Data Relay System (EDRS). This Call for Interest has garnered enough responses to prompt the release of an Invitation to Tender in the near future.
For more information see the links in the column to the right.
