Blockstream launched a satellite service. It did not launch a satellite.
Bitcoin blocks are being broadcast by Blockstream, by contracting with several existing several satellite systems. These satellites are primarily designed for broadcasting TV signals, and thus don't run their own full nodes; the broadcast is dependent on ground stations that uplink ...
No, communication is unidirectional, you can only receive the data which is broadcast by the system. The satellites being used are TV relays, the uplink essentially being amplified and re-broadcast without any knowledge of the content.Transaction broadcast needs to happen by terrestrial services like a cellphone network, dialup modem, or just the regular ...
Blockstream have multiple satellite circling around the earth and broadcasting the blockchain or receiving and sending transaction without interruption.
They have their own kit to use the service: