Smart contracts on Ethereum are fully self contained and any information or access to off-chain data is restricted. Tellor solves this problem by creating a system where parties can request the value of an off-chain data point (e.g. ETH/USD) and miners compete to add this value to an on-chain data bank, accessible by all Ethereum smart contracts. Inputs to a data series are secured by a network of staked miners. The main Tellor smart contract creates a time series of each requested data series and aims to become the standard source of high value data for decentralized applications. This oracle, “Tellor”, utilizes similar incentive mechanisms to other cryptocurrency systems through the issuance of Tellor’s token, Tributes, that are used to request a particular data series from miners.
The key to Space Chain is to deploy all blockchain nodes on satellites so as to bring blockchain technology into space, adding a new dimension to blockchain’s core concept of distributed ledger by making use of space technology and advantages of space resources. As a space blockchain platform featuring data collecting, computing, application and storage, Space Chain uses satellites as its blockchain nodes for realizing direct on-satellite data processing and secure in-space data storage through cryptographic technologies such as quantum communications. Different from ground-network-based blockchain technology, Space chain provides a broader coverage and is based on a network of LEO satellites for achieving broad-based connectivity so that anyone and anything could become the user of blockchain technology anywhere and anytime.