Nasa has awarded a contract for the Total and Spectral Solar Irradiance Sensor-2 (TSIS-2) to the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder.

The new sensor will provide continuity to data delivered by TSIS-1, which was launched in December 2017.

Worth $18m, this cost-no-fee sole-source contract has a period of performance ending with on-orbit acceptance by the government, which definitises a letter contract that was issued in August last year.

As part of the Earth Systematic Missions (ESM) programme, development and operation of the TSIS-2 are managed by NASA’s Goddard Space Flight Center (GSFC). The sensor is expected to launch in 2023.

The scope of the contract encompasses the provision of two instruments, the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM).

All associated support to integrate and test the instruments with the spacecraft will be provided by the laboratory.

The extended support includes all post-launch activities that lead to commissioning.

LASP will also be responsible for the establishment of the TSIS-2 Science Operations Center (TSOC).

The instruments used are identical to the others used during the operation of TSIS-1.

A 40-year uninterrupted measurement record of the Total Solar Irradiance (TSI) will be provided by the TIM. TSI is the Earth’s predominant energy source.

The SIM will continue to measure the Solar Spectral Irradiance (SSI) and identify the surfaces and regions in Earth’s atmosphere that are affected by solar variability.

The sensor will continue to collect high-quality data for the long-term climate record and measure the Sun’s energy input to Earth.

These measurements will help the scientific community to understand solar influences on the Earth’s climate.