Minimize SWFO-L1

SWFO-L1 (Space Weather Follow-On Lagrange 1) Satellite Mission

Development Status     Launch    Sensor Complement    References

Space Weather Follow-On (SWFO) is a NOAA environmental satellite program under development by OPPA (Office of Projects , Planning and Analysis) at NOAA. Its mission is to provide space weather observations to enable space weather forecasting by NOAA. SWFO will make direct, in-situ, measurements of the solar wind thermal plasma and magnetic field “up-stream” of the Earth. In addition, SWFO will observe the Sun’s corona to detect expulsions of plasma and magnetic field, called Coronal Mass Ejections (CMEs), which may be directed towards the Earth. The data produced by SWFO will help NOAA provide watches and warnings for space weather events that can disrupt the electrical power grid and communications systems as well as navigation and timing systems like the Global Positioning System (GPS). 1)


Figure 1: A dramatic coronal mass ejection event (CME) on August 31, 2012, captured by NASA's STEREO mission and the joint ESA/NASA SOHO mission. The size of the Earth is shown relative to the size of the CME filament (image credit: NASA Goddard Media Studios)

The SWFO program is comprised of two projects: CCOR (Compact Coronagraph) on the GOES-U spacecraft and the Space Weather Follow-On L1 mission (SWFO-L1). 2)

The SWFO-L1 (Space Weather Follow-On L1) mission will orbit the Sun at approximately 1.5 million kilometers from Earth on the Earth-Sun line, a point known as L1. The SWFO-L1 mission will use a suite of instruments to make in-situ measurements of the solar wind thermal plasma and magnetic field as well as a CCOR instrument to detect CMEs. The L1 orbit allows for continuous unobstructed observation of the corona without interference from the Earth.


Figure 2: Diagram showing the relative position of the Sun and the Earth and the five Lagrange points, with contour lines of the effective potential. (image credit: NASA)


Figure 3: A coronal mass ejection event on Feb 27, 2000, captured by the LASCO instruments C2 and C3 on ESA's SOHO mission (image credit: ESA SOHO & NASA)

NOAA is preparing to update its aging space weather fleet with instruments to gather imagery of coronal mass ejection and monitor solar winds. Congress provided NOAA funding in the 2020 budget for Space Weather Follow On (SWFO), a satellite destined for Earth-Sun Lagrange Point 1. The Commerce Department also gave NOAA the green light in 2019 to begin procuring elements of SWFO, which is designed to carry on work performed by NOAA’s DSCOVR (Deep Space Climate Observatory) launched in 2015 and the joint European Space Agency-NASA SOHO (Solar and Heliophysics Observatory) launched in 1995. 3)

The SWFO-L1 will carry the Compact Coronagraph of NRL (Naval Research Laboratory) and a suite of instruments to measure solar wind.

NOAA is the U.S. government agency charged with monitoring space weather and issuing alerts, watches and warning. NOAA issues alerts, for example, concerning geomagnetic storms and solar radiation storms.

To gather additional space weather observations, NOAA is preparing to send a second Compact Coronagraph into orbit in 2025 on GOES-U (Geostationary Operational Environmental Satellite-U).

“That’s a pathfinder for future capabilities,” Elsayed Talaat, NOAA's OPPA (Office of Projects, Planning and Analysis) director, said January 13 at the American Meteorological Society conference here. In the future, NOAA may elect to mount coronagraphs on all its geostationary satellites to obtain reliable, round-the-clock data, he added.

NOAA plans to send commands to the SWFO-L1 mission in S-band and to downlink science data in X-band. Although the agency’s primary communications facilities are in Virginia on Wallops Island, NOAA is looking for domestic and international partners to provide additional downlink capability, Talaat said.

Development status

• July 29, 2021: Ball Aerospace successfully completed the preliminary design review (PDR) for the National Oceanic and Atmospheric Administration's (NOAA's) Space Weather Follow On-Lagrange 1 (SWFO-L1) spacecraft. With PDR complete, the spacecraft now moves into the critical design phase. 4)

- Ball was awarded the contract to design and build the SWFO-L1 spacecraft on June 25, 2020 by NASA's Goddard Space Flight Center on behalf of NOAA. SWFO-L1 is an operational mission that will collect solar wind data and coronal imagery to meet NOAA's operational requirements to monitor and forecast solar storm activity. SWFO-L1 will be launched to an L1 orbit, which will allow for upstream solar wind measurements and continuous unobstructed observation of the sun's corona without interference from the Earth.

- "Space weather events, such as solar flares, coronal mass ejections and other high-energy emissions from the sun, can endanger astronauts in space, interfere with satellites and damage communications and power grid infrastructure, causing significant economic impact," said Dr. Makenzie Lystrup, vice president and general manager, Civil Space, Ball Aerospace. "Once on orbit, SWFO-L1 will provide the nation with critical space weather information to help protect life and property and we are excited to partner with NOAA and NASA Goddard on this important mission."

- The SWFO-L1 spacecraft is based on the Ball Configurable Platform (BCP), which is a customizable and proven spacecraft, designed for flexible, cost-effective applications, using a common spacecraft bus and standard payload interfaces to reduce cost, streamline payload accommodation and minimize delivery time. Ball has a heritage of building spacecraft for NOAA's operational weather missions, including NOAA-20 and the Suomi National Polar Orbiting Partnership (Suomi NPP).

• May 14, 2021: NOAA has awarded an antenna contract to the company KBR Inc. of Houston, Texas, to deploy, develop and operate the agency’s Space Weather Follow-On (SWFO-L1) Antenna Network. 5)

- KBR’s space weather follow-on antenna network is being built to transmit continuous mission data with the SWFO-L1 observatory and its ground segment. It is expected to perform telemetry, command and ranging services for the observatory’s operations, KBR said Thursday.

- The SWFO-L1 spacecraft, which the antenna network will be supporting, is set to be deployed in space in the future to monitor signs of solar storms. Using a suite of instruments, the spacecraft will make in-situ measurements of the solar wind thermal plasma and magnetic field and detect coronal mass ejections.

- If all options are exercised, work for the cost-plus-fixed-fee for contract will be completed in five years. Contract work will be carried out in facilities in Fulton and Suitland in Maryland, as well as in Wallops, Virginia, and Fairmont, West Virginia.

• February 19, 2021: For more than five decades, the National Oceanic and Atmospheric Administration’s (NOAA) has created a more weather-ready nation. L3Harris has been along for the 50-year ride designing, building and delivering mission-critical weather sensors and ground systems for the agency. 6)

- In February 2021, L3Harris was selected to develop and deploy the ground system command and control (C2) for NOAA’s environmental satellite program, Space Weather Follow On (SWFO). L3Harris will perform up to two years of operations support for the SWFO observatory as part of this contract. The SWFO mission will utilize the ground system for NOAA’s Geostationary Operational Environmental Satellites-R (GOES-R). L3Harris’ Advanced Baseline Imager (ABI) is the primary payload onboard GOES-R and the company designed and built the scalable ground system for the satellite.

- The SWFO spacecraft will collect space weather data, such as continuous data from coronal mass ejections and solar flares, that can damage spacecraft and disrupt electrical power grid and communications and will provide an advanced warning for such events.

- “The Space Weather Follow On (SWFO) Command and Control contract awarded to L3Harris Technologies confirms NOAA’s ongoing confidence in us to deliver a mission-relevant capability which meets their needs,” said Rob Mitrevski, Vice President and General Manager, Spectral Solutions, Space and Airborne Systems, L3Harris. “L3Harris initially designed the GOES-R ground system as an Enterprise Solution scalable to efficiently add new missions, such as SWFO, and deliver critical data to a variety of end users.”

- Scheduled to launch in 2025, the SWFO mission is planned as a ride share with the NASA IMAP (Interstellar Mapping and Acceleration Probe).

- In related news, L3Harris delivered the Cross-track Infrared Sounder (CrIS) instrument for NOAA’s Joint Polar Satellite System-2 (JPSS2) in January 2021. The advanced CrIS instrument provides detailed, three-dimensional temperature and moisture data from both the Suomi National Polar-orbiting Partnership and JPSS/NOAA satellites. JPSS-2 is the second of NOAA’s latest generation of U.S. polar-orbiting, non-geosynchronous, environmental satellites.

• February 5, 2021: NOAA has awarded the Space Weather Follow On-Lagrange 1 (SWFO-L1) Command and Control contract to L3Harris in Melbourne, Florida. The cost plus fixed-fee contract has a total value of $43,784,063, with a five-year performance period. The SWFO-L1 mission is planned to launch in 2025 as a ride share with the NASA Interstellar Mapping and Acceleration Probe. 7)

- The contractor is responsible for development, deployment, and for up to two years of operations support of a Command and Control of the SWFO-L1 observatory. This will be accomplished by adding the capability to existing Geostationary Operational Environmental Satellite - R Series Core Ground System.

- The NOAA Satellite and Information Service’s Office of Projects, Planning and Analysis will manage the contract. In addition to work at L3Harris’ facility in Melbourne, the contractor will install equipment at the NOAA Satellite Operations Facility (NSOF) in Suitland, Maryland; NOAA’s Wallops Command and Data Acquisition Station (WCDAS) in Wallops, Virginia; and at NOAA’s Consolidated Backup Facility (CBU) in Fairmont, West Virginia.

- The work will allow SWFO L1 to provide continuity of solar wind and coronal mass ejection imagery data from the Lagrange-1 point to NOAA’s National Weather Service Space Weather Prediction Center in Boulder, Colorado. These data are critical to support monitoring and timely forecasts of space weather events that have the potential to adversely impact elements vital to national security and economic prosperity, including telecommunication and navigation, satellite systems and the power grid.

- NOAA is responsible for overall implementation and funding of the SWFO program. The program is managed as an integrated NOAA-NASA program, where NASA serves as NOAA’s acquisition agent for the space segment and for launch services. NOAA is responsible for the ground segment including the acquisition, development, test and integration of the SWFO Command and Control system.


Figure 4: Artist's rendering of the SWFO-L1 spacecraft in orbit. The SWFO-L1 is designed to carry on work performed by NOAA’s Deep Space Climate Observatory (DSCOVR) launched in 2015 and the joint European Space Agency-NASA Solar and Heliophysics Observatory launched in 1995 (image credit: NOAA)

• July 1, 2020: On behalf of NOAA, NASA has awarded the Space Weather Follow On-Lagrange 1 (SWFO-L1) Solar Wind Plasma Sensor (SWiPS) contract to South West Research Institute (SwRI) in San Antonio, Texas. 8)

- This is a cost plus fixed-fee contract with a total value of $15,579,930. The performance period begins on July 1 and runs for 76 months. The work will be performed at SwRI’s facility in San Antonio, Texas.

• June 25, 2020: On behalf of NOAA, NASA has awarded a delivery order under the Rapid Spacecraft Acquisition III (Rapid III) contract to BATC (Ball Aerospace & Technologies Corp.) of Boulder, Colorado, for the Space Weather Follow On-Lagrange 1 (SWFO-L1) spacecraft. 9)

- This is a firm fixed-price delivery order in the amount of $96.9 million issued under the Rapid III Spacecraft Catalog. The period of performance runs now through March 31, 2025.

- The contractor shall design and fabricate the SWFO-L1 spacecraft bus, integrate the government-furnished instruments and perform satellite-level testing, support and training of the Flight Operations Team, as well as in-orbit satellite check-out and mission operations support.

- The Rapid III contract provides a rapid and flexible means to procure spacecraft in support of the scientific and technology development goals of NASA and other federal agencies.

• April 15, 2020: On behalf of the National Oceanic and Atmospheric Administration (NOAA), NASA has awarded the Space Weather Follow-On Lagrange 1 (SWFO-L1) Magnetometer contract to SwRI ( Southwest Research Institute) based in San Antonio, Texas. 10)

- SwRI will design, analyze, develop, fabricate, integrate, test, calibrate and evaluate the magnetometer instrument that consists of two three-axis magnetometers and associated electronics that will be used to measure the vector interplanetary magnetic field. SwRI will also support launch and on-orbit check-out of the instrument, supply and maintain the instrument Ground Support Equipment and support the Mission Operations Center through mission hand-over to NOAA.

- The work will be performed at SwRI in San Antonio, Texas, and at the University of New Hampshire in Durham.

- The SWFO-L1 satellite, which is planned to launch in 2024 as a rideshare on the NASA IMAP (Interstellar Mapping and Acceleration Probe) mission, will collect upstream solar wind data and coronal imagery to support NOAA’s mission to monitor and forecast space weather events.

- NOAA is responsible for the Space Weather Follow-On program. NASA is the program's flight system procurement agent, and NASA Goddard Space Flight Center in Greenbelt, Maryland, is the lead for acquisition.

Launch: A launch of SWFO-L1 is planned for 2025. SWFO-1 is a rideshare mission with the NASA IMAP (Interstellar Mapping and Acceleration Probe), to collect upstream solar wind data and coronal imagery to support NOAA’s mission to monitor and forecast space weather events.

Orbit: The orbit of SWFO-L1 is around the the L1 (Lagrangian Point-1) about 1.5 million km from Earth in the direction of the sun.

Sensor complement (CCOR, MAG, STIS, SWIPS)

The objective of this mission is to provide critical data in near-real time that supports space weather forecasting efforts.

CCOR (Compact Coronagraph)

The CCOR instrument is being developed for space weather forecasting at OPPA (Office of Projects planning and Analysis) of NRL (Naval Research Laboratory) in Washington D.C. CCOR will image the solar corona and be used to observe Coronal Mass Ejections (CMEs). With CCOR data the size, mass, speed, and direction of CMEs can be derived. With this information forecasters can provide watches for impending geomagnetic storms over one day in advance.

MAG (Magnetometer)

The MAG instrument is provided by SwRI (Southwest Research Institute) and the University of New Hampshire in cooperation with the Austrian Academy of Sciences. The instrument consists of a "dual mag" implementation of two identical racetrack magnetometers on a 6-meter boom (a dual mag system is commonly used to reduce the dipole signature of spacecraft magnetic fields). The "racetrack" design incorporates an optimal geometry for fluxgate magnetometers, one that maximizes the alignment of the permalloy material (and windings) along the measurement axis.

STIS (Supra Thermal Ion Sensor)

On behalf of NOAA, NASA awarded the STIS contract to the University of California, Berkeley (UCB).

SWIPS (Solar Wind Plasma Sensor)

SWiPS will measure the properties of solar wind ions originating from the Sun, including the very fast ions associated with coronal mass ejections that interact with the Earth's magnetic environment. 11)

"The satellite will collect solar wind data and coronal imagery to support NOAA's mission to monitor and forecast space weather events," said Dr. Robert Ebert, a principal scientist in SwRI's Space Science and Engineering Division and SWiPS principal investigator.

"The SWiPS sensor design is based on the IES (Ion and Electron Sensor) flown on ESA's comet mission, Rosetta," said Prachet Mokashi, a program manager in SwRI's Space Science and Engineering Division and the project manager for SWiPS. "The compact design, low resource requirements and ideal data production make this a well-suited instrument for the SWFO-L1 mission."

1) ”Space Weather Follow-On,” NOAA/OPPA, URL:

2) ”Space Weather Follow-On L1 mission,” NOAA/OPPA, URL:

3) Debra Werner, ”NOAA set to update space weather fleet,” SpaceNews, 13 January 2020, URL:

4) ”Ball Aerospace Completes Preliminary Design Review of NOAA's Space Weather Satellite,” PR Newswire, 29 July 2021, URL:

5) ”NOAA Taps KBR to Build Space Weather Antenna Network,” Potomac Officers Club, 14 May 2021, URL:

6) ”L3Harris Selected to Develop the Ground System Command and Control for NOAA’s Space Weather Follow On Observatory,” L3Harris, 19 February 2021, URL:

7) ”NOAA awards SWFO Ground System Command and Control contract,” NOAA News, 5 February 2021, URL:

8) ”NASA Awards NOAA’s Space Weather Follow On-Lagrange 1 (SWFO-L1) Solar Wind Plasma Sensor (SWiPS),” NASA Contract Release C20-014, 1 July 2020, URL:

9) Steve Cole, ”NASA Awards NOAA’s Space Weather Follow On-Lagrange 1 Spacecraft,” NASA Contract Release, C20-013, 25 June 2020, URL:

10) ”NASA Awards NOAA's Space Weather Follow-On Lagrange 1 Magnetometer,” NASA Contract Release CO20-008, 15 April 2020, URL:

11) ”SwRI awarded contract to develop solar wind plasma sensor,” SwRI, 22 July 2020, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

Development Status     Launch    Sensor Complement    References    Back to top