An illustration of the GOES 16 (formerly GOES-R) satellite, launched in November 2016. Credit: Lockheed Martin

WASHINGTON — The latest in a series of geostationary weather satellites is ready for launch as NASA takes the next step in plans for a next generation of such spacecraft.

The Geostationary Operational Environmental Satellite (GOES) T satellite is scheduled to launch at 4:38 p.m. Eastern March 1 on a United Launch Alliance Atlas 5 from Cape Canaveral Space Force Station in Florida. At a Feb. 26 briefing, mission officials said the spacecraft and rocket were ready for launch, with the main concern the weather: forecasts projected a 60% chance of acceptable conditions March 1, rising to 70% if the launch is delayed a day.

GOES-T, which will be renamed GOES-18 if successfully launched, will replace GOES-17 at the GOES-West orbital slot at 137 degrees west by early 2023. While GOES-17 was launched only four years ago, problems with its main instrument, the Advanced Baseline Imager (ABI), prompted NOAA to replace it with GOES-T. GOES-17 will be placed into on-orbit storage to be activated in the event problems with another satellite.

GOES-T is the third of four satellites in the GOES-R series. “The GOES-T satellite is very similar to its older siblings but has design changes incorporating lessons learned from GOES-R and -S on orbit,” said Pam Sullivan, director of the GOES-R program at NOAA, at the prelaunch briefing.

Design changes to the radiator on ABI, which caused the problems seen on GOES-17, is the biggest change, she said. GOES-T also has a new magnetometer for space weather observations.

The fourth and final satellite in the GOES-R series, GOES-U, is scheduled to launch in 2024 on a SpaceX Falcon Heavy. It will be similar to the first three but will also include a compact coronagraph instrument built by the Naval Research Lab for space weather monitoring, Sullivan said.

NASA and NOAA have started planning on the next generation of geostationary orbit weather satellites, called Geostationary Extended Operations or GeoXO. Those satellites, scheduled to start launching in the early 2030s, will continue the measurements made by the GOES-R series but also include new instruments such as a hyperspectral infrared sounder and atmospheric composition sensor. As with earlier GOES satellites, NASA will handle procurement and development work on the GeoXO satellites for NOAA.

“The breadth of these observations are needed to meet the integrated and the growing climate observation measurements that are really needed to understand the planet,” said Steve Volz, NOAA assistant administrator for satellite and information services, at the briefing.

While the first GeoXO satellite isn’t scheduled for launch until 2032, NASA has already started the procurement process for those spacecraft. The agency issued a request for proposals Feb. 24 for definition studies of the GeoXO spacecraft. NASA plans to award up to two Phase A study contracts in July, valued at up to $5 million over 10 months.

According to the statement of work for that procurement, GEOXo will include six satellites that will operate at the GOES-East and GOES-West locations as well as a new GOES-Central orbital slot at 105 degrees west. The satellites at GOES-Central will carry new hyperspectral infrared sounder and atmospheric composition instruments, as well as an unspecified “partner payload.” The six satellites are projected to launch between 2032 and 2042.

The studies will have to demonstrate whether the spacecraft can be launched on the Falcon Heavy as well as ULA’s Vulcan Centaur and Blue Origin’s New Glenn vehicles. The studies will also examine trade-offs between launching the satellites into geostationary transfer orbits, from which the spacecraft would use onboard propulsion to go to GEO, versus direct injection into GEO by the launch vehicle. The latter approach allows the spacecraft to immediately arrive in GEO but requires higher performance by the launch vehicle.

The GeoXO studies will also examine the potential for “limited, on-orbit robotic servicing” of the spacecraft, such as refueling. That would require the addition of equipment such as grappling fixtures and visual fiducials to assist a servicing spacecraft docking with the GeoXO satellite. The statement of work, though, says that individual spacecraft components “do not need to be specifically designed to be serviceable.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...