A planned launch of twin satellites for a study on the sun’s energy lead by a University of Iowa professor is now scheduled for Wednesday.

The Tuesday was called off due to “FAA airspace concerns.” SpaceX announced the change of plans on social media.

A 57-minute launch window will open at 1:13 p.m. Central time. The mission will take off from Space Launch Complex 4 East at Vandenberg Space Force Base in California. You can watch the launch live on the .

The satellites will fly in tandem over Earth’s poles, collecting data on solar storms and space weather. Scientists say the mission could help protect satellites, astronauts, and power grids from solar disruptions.

Update July 22, 6 p.m. EDT: Added comment from the FAA.

NASA’s next trip to space will be a rideshare mission with nine other satellites sharing a SpaceX Falcon 9 rocket. However, it has to wait at least another day after a last minute scrub of the mission.

About 45 seconds before the planned liftoff, the SpaceX launch director called, “Hold, hold, hold” and declared that the mission was aborted due to “air space concerns.”

Following the scrub, SpaceX took to social media to reiterate that it wasn’t able to proceed into launch “due to [Federal Aviation Administration] airspace concerns that created a no-go condition for launch.” SpaceX said it would try again on Wednesday.

In a statement to Spaceflight Now, the FAA said a power issue was to blame for the scrub.

“A regional power outage in the Santa Barbara area disrupted telecommunications at the Los Angeles Air Route Traffic Control Center, which manages air traffic over the Pacific Ocean,” an FAA spokesperson said in a statement. “As a result, the FAA postponed the SpaceX Falcon 9 TRACERS launch on Tuesday, July 22. The FAA took this action to ensure the safety of the traveling public.”

When they launch, NASA’s twin Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites or TRACERS will study the interplay between the solar wind and Earth’s magnetosphere.

Liftoff of the mission from Space Launch Complex 4 East at Vandenberg Space Force Base is now scheduled for Wednesday, July 23, at 11:13 a.m. PDT (2:13 p.m. EDT, 1813 UTC), which is the opening of a 57-minute launch window.

Spaceflight Now will have live coverage beginning about 30 minutes prior to liftoff.



SpaceX will use the Falcon 9 first stage booster with the tail number B1081 to launch this mission. Flying for a 16th time, it previously flew NASA’s Crew-7, CRS-29 and NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) spacecraft.

Just under eight minutes after liftoff, B1081 will target a touchdown back at Landing Zone 4. If successful, this will be just the 27th landing at LZ-4 and the 478th booster landing to date for SpaceX.

Those in the vicinity of Vandenberg SFB may experience a sonic boom as the booster makes its way back through the atmosphere for a landing.

Understanding Earth’s magnetic field

The twin TRACERS at the heart of Tuesday’s mission are set to deploy on a one-year mission following a month-long commissioning period.The identical, octagonal duo, dubbed T1 and T2, are each 37 inches (0.95 m) tall and 52 inches (1.32 m) across, weighing less than 440 pounds (200 kg) apiece.

They will fly in a Sun-synchronous, low Earth orbit at an altitude of 367 miles (590 km) above the Earth’s surface. Their polar orbit will see the twins fly repeatedly through regions known as cusps, described by NASA as “funnel-shaped regions where Earth’s magnetic field opens over the North and South Poles.”

“There, Earth’s magnetic field dips down toward the ground, funneling and concentrating particles into one part of our atmosphere,” NASA wrote about the mission. “By studying this region, TRACERS will allow scientists to observe how quickly reconnection changes and evolves by comparing data collected by each satellite.”

Reconnection on Earth, also referred to as magnetic reconnection, is when the solar wind from the Sun reaches Earth’s magnetosphere shoot directly into the atmosphere.

“That’s the primary driver for beautiful things… like the Northern Lights, but it also drives some of these negative things that we want to understand and mitigate, like unplanned electrical currents in our electrical grids that can potentially cause accelerated aging in electrical pipelines, disruption of GPS, things like that,” said David Miles, the TRACERS Principal Investigator at the University of Iowa, during a prelaunch briefing.



TRACERS follows in the footsteps of the TRICE (Twin Rockets to Investigate Cusp Electrodynamics)-2 mission, which featured a pair of sounding rockets launched back in December 2018. TRACERS has the benefit of a pair of satellites that will orbit close to on another and pass by the same point on Earth between 10 to 120 seconds later.

“That gives us two, closely spaced measurements to allow us to pick apart is something accelerating or slowing down? Is something moving around or is something turning on and off?” Miles said. “Each spacecraft is going to get a measurement of basically the local state of the plasma, like the electric field, the magnetic field and the local ions and electrons that compose the plasma.”

The TRACERS mission is part of NASA’s Small Explorers (SMEX) program, similar to PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission that launched in March. TRACERS has a mission cost of $170 million.

The spacecraft were built by Millennium Space Systems, which is now a Boeing company. The mission is led by the University of Iowa and managed by NASA’s Heliophysics Explorers Program Office.

Each satellite carries six instruments as outlined by NASA:

ACE: The Analyzer for Cusp Electrons measures the electron portion of local plasma and how they move with respect to the background magnetic field.

The Analyzer for Cusp Electrons measures the electron portion of local plasma and how they move with respect to the background magnetic field. ACI: The Analyzer for Cusp Ions measures the ion portion of local plasma and how they move with respect to the background magnetic field.

The Analyzer for Cusp Ions measures the ion portion of local plasma and how they move with respect to the background magnetic field. MAG: The 3-axis fluxgate magnetometer measures the background magnetic field of plasma. It can also be used to infer the presence of electrical currents and low frequency plasma waves.

The 3-axis fluxgate magnetometer measures the background magnetic field of plasma. It can also be used to infer the presence of electrical currents and low frequency plasma waves. MSC: The 3-axis Magnetic Search Coil measures high frequency magnetic waves.

The 3-axis Magnetic Search Coil measures high frequency magnetic waves. MAGIC: The MAGnetometers for Innovation and Capability team is building fluxgate magnetometers from scratch and investigating new designs. As a technology demonstration on TRACERS, MAGIC must do no harm to the other instruments while testing its designs for future space missions.

The MAGnetometers for Innovation and Capability team is building fluxgate magnetometers from scratch and investigating new designs. As a technology demonstration on TRACERS, MAGIC must do no harm to the other instruments while testing its designs for future space missions. MEB: The common Main Electronics Box hosts the electronics for electronic field instruments, MSC, and MAG.

Along for the ride

The two TRACERS spacecraft are joined by nine others spread across three, NASA-funded missions, one ESA mission and one from an Australian company promising air traffic control from space. The NASA-involved payloads are the Athena EPIC (Economical Payload Integration Cost) SmallSat backed by SEOPS, the technology demonstration PExT (Polylingual Experimental Terminal) backed by York Space Systems and the REAL (Relativistic Electron Atmospheric Loss) CubeSat backed by Maverick Space Systems.

Athena EPIC is a $15 million mission born out of a challenge from NASA’s Langley Research Center director to see what could be accomplished a seven-month timeframe. Private company, NovaWurks, contributed the spacecraft that was assembled with a Hyper-Integrated Satlet or HISat.

This is described by NASA as a building block-style architecture that can be built up into larger SensorCraft structures, allowing for resource sharing with multiple payloads. Athena EPIC’s sensor was built using spare parts from NASA’s CERES (Clouds and the Earth’s Radiant Energy System) mission.

“Instead of Athena carrying its own processor, we’re using the processors on the HISats to control things like our heaters and do some of the control functions that typically would be done by a processor on our payload,” said Kory Priestley, principal investigator for Athena EPIC from NASA Langley. “So, this is merging an instrument and a satellite platform into what we are calling a SensorCraft. It’s a more integrated approach. We don’t need as many capabilities built into our key instrument because it’s being brought to us by the satellite host. We obtain greater redundancy, and it simplifies our payload.”

The mission includes cooperation from National Oceanic and Atmospheric Administration (NOAA) and the U.S. Space Force. Priestley said latter provided the contract mechanism to align with NovaWurks and NOAA is interested the maturation of a program like this for future commercial missions for the National Weather Service.

The PExT mission has a $20 million life cycle cost over its planned five-year life. The initial demonstration for this mission is only slated for six to nine months. It exists within NASA’s Space Communications and Navigation (SCaN) program and is a collaboration between the agency’s Wideband Terminal Project and the Johns Hopkins University Applied Physics Laboratory (APL).

The polylingual nature of the spacecraft allows it to “receive and understand various languages used by different commercial manufacturers when operating in their near-Earth networks,” the agency said. Its wide frequency allows it to reach across the full scope of both commercial and government Ka-band allocations “including 17.7 GHz to 23.55 GHz Forward, and 27 GHz to 31 GHz Return.”

NASA is working on ways to move beyond its aging TDRSS (Tracking and Data Relay Satellite System) used to communicate with a host of spacecraft.

“We partnered with five members of industry and acadamia to achieve this mission,” said Greg Heckler, the deputy program manager for capability development at SCaN. “[APL] developed the terminal and is managing projects for SCaN. The terminal is mounted on a York Space Systems bus, and they actually procured the launch itself, and will be operating the spacecraft for the first year of the demonstration.

“And during the demo, PExT will communicate across our TDRSS and two commercial networks: SES’ O3b mPOWER network, which is being actually established as we speak, and Viasat Boeing Global Xpress network as well.”

Finally connected to NASA, the mission will carry the $5 million REAL CubeSat, which carries the Energetic Particle Sensor (ECP) payload, a miniaturized particle detection instrument from APL. It’s designed to “characterize the forces that cause electrons in Earth’s radiation belts to fall into the atmosphere, space weather events that affect the upper atmosphere — potentially even the climate — and can damage the increasing number of satellites in low Earth orbit.”

The REAL spacecraft was built and tested at Montana State University, which features a design that upgrades what MSU used during on its IT-SPINS (Ionospheric-Thermospheric Scanning Photometer for Ion-Neutral Studies) CubeSat that deployed in June 2021 from Northrop Grumman’s Cygnus spacecraft at the conclusion of the NG-15 mission to the International Space Station.

Connectivity and air traffic control

The other two missions onboard the Falcon 9 rocket are LIDE (Direct Access Live Demonstration) and Skykraft 4. The former is one half of a two-mission project from the European Space Agency’s Connectivity and Secure Communications office.

LIDE is a 12U CubeSat developed by Tyvak International, now a part of Terran Orbital (in turn, a Lockheed Martin company) that uses a bidirectional K/Ka-band radio frequency transponder “to enable direct access tests with ground terminals— a gateway and an end-user terminal—compliant with 3GPP’s NTN standard.”

The satellite will work with the REMI (Direct Access 5G Satcom Reference Mission) mission, which “focuses on a feasibility study for providing 5G broadband access to rural and suburban areas via a SmallSats.”

“The platform’s active attitude determination and control system ensures optimized satellite orientation for enhanced signal reception,” ESA wrote in a prelaunch statement. “In essence, the present solution aims to demonstrate techniques and technologies enabling superior performance, broader coverage, and enhanced reliability, offering unmatched value to users and stakeholders alike. The project is significant for advancing European telecommunication capabilities, with implications for future 3GPP protocols and 6G technology.”

Australian company Skykraft will oversee the deployment of five of its spacecraft during this mission. These will be the final payloads deployed from the Falcon 9 upper stage, happening about an hour and 45 minutes after liftoff.

This constellation is designed to establish a system of space-based Air Traffic Management (ATM) services.

UPDATE (2:15 p.m.) – According to the FAA, the delay was due to a regional power outage in the Santa Barbara area that the agency reports “disrupted telecommunications at the Los Angeles Air Route Traffic Control Center, which manages air traffic over the Pacific Ocean. As a result, the FAA postponed the SpaceX Falcon 9 TRACERS launch on Tuesday, July 22. The FAA took this action to ensure the safety of the traveling public.”

The outage also affected flights at airports in San Luis Obispo and Santa Barbara counties on Tuesday.

___

UPDATE (11:14 a.m.) – SpaceX’s launch of the NASA TRACERS mission was scrubbed Tuesday, due to airspace concerns.

A hold was placed on the launch just 43 seconds before the rocket was scheduled to lift off, and officials announced they were standing down from the launch attempt.

SpaceX says it will try again on Wednesday with the launch window opening at 11:13 a.m.

___

SpaceX plans to launch a Falcon 9 rocket from Vandenberg Space Force Base on Tuesday, and area residents may hear a sonic boom.

The 57-minute launch window opens at 11:13 a.m.

WATCH:

Watch Falcon 9 launch the @NASA TRACERS mission to orbit from California https://t.co/fGxqX4AlAQ — SpaceX (@SpaceX) July 22, 2025

About eight minutes after liftoff, SpaceX will aim to land the rocket’s first stage booster back on land at Vandenberg Space Force Base. This is likely to produce one or more sonic booms that people in Santa Barbara, San Luis Obispo and Ventura counties may be able to hear.

The rocket will be delivering a NASA payload called TRACERS (Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites) into low-Earth orbit. The twin satellites will study how solar wind impacts the Earth’s magnetic field. According to NASA, this information will help scientists better understand and prepare for impacts to Earth, such as auroras and disruptions to telecommunications.

TRACERS through Earth’s Polar Cusps

Visualization of the orbit of the twin TRACERS satellites (pink) exploring electricity and magnetism in Earth’s polar regions. The light-blue ‘flows’ represent the particle currents traveling from the edge of the magnetosphere, through the region of the ionosphere, and back out to the magnetosphere. (Video courtesy NASA)

Several other satellites will also be along for the ride, including SEOPS’ Epic Athena, Skykraft’s Skykraft 4, Maverick Space Systems’ REAL, Tyvak’s LIDE, and York Space Systems’ Bard.

If Tuesday’s launch is scrubbed, SpaceX says it has a backup launch opportunity at the same time on Wednesday.

Update March 12, 1:52 a.m. ET: NASA confirms acquisition of signal.

NASA launched its first ride share flight in support of the Science Mission Directorate with two missions flying on the same SpaceX Falcon 9 rocket Tuesday night. It came following a last-minute issue that NASA described as “a SPHEREx ground data-flow issue,” which caused the mission to scrub on Monday.

Onboard the Falcon 9 rocket were the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) observatory and four spacecraft that make up the Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission.

Liftoff from Space Launch Complex 4 East at Vandenberg Space Force Base happened Tuesday, March 11, at 8:10 p.m. PDT (11:10 p.m. EDT, 0310 UTC). NASA confirmed acquisition of signal shortly after SPHEREx separated from the Falcon 9 and was reportedly power positive.

Mission controllers were also able to gain communications with the four spacecraft that make up the PUNCH mission as well.



A joint NASA-SpaceX launch readiness review was held on Friday and the mission was then scheduled for Saturday, but then NASA announced that it was standing down from launching that day to “allow teams to continue rocket checkouts ahead of liftoff.”

Previous payloads from SMD purchased dedicated flights on rockets through NASA’s Launch Services Program (LSP), which is managed by the Kennedy Space Center in Florida. During a prelaunch news conference, Mark Clampin, the acting deputy associate administrator for SMD described the upcoming launch as being “a real change in how we do business.”

“We call this a ride share and it’s a new strategy that SMD is working, where we can maximize the efficiency of launches by flying two payloads at once, so we maximize our science return,” Clampin said. “The other thing I think is really important to understand is not only are we launching two missions at once, but these missions cover the full breadth of the science that NASA does every day. So, we’re really excited by this launch.”

Julianna Scheiman, the director of NASA Science Missions for SpaceX, noted that while this is the first SMD rideshare mission of the year, it won’t be the last. The agency’s Interstellar Mapping and Acceleration Probe (IMAP) and Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) missions will launch on a rideshare mission later this year.

Scheiman didn’t state which mission would carry IMAP and TRACERS, but a Dec. 20, 2024 press release from the Johns Hopkins Applied Physics Laboratory (APL) said that NASA and SpaceX were targeting “as soon as September 2025” to launch IMAP. A separate blog post from NASA dated the same day said IMAP would fly alongside the agency’s Carruthers Geocorona Observatory and the National Oceanic and Atmospheric’s (NOAA) Space Weather Follow On – Lagrange 1 mission.

“It’s a big rideshare year for Falcon and for NASA Science. Very exciting!” Scheiman said. “I personally came to SpaceX because I wanted to help lower the cost of access to space, which in turn helps us enable more scientific exploration. So, I’m really proud that we can be doing that together.”

The Falcon 9 first stage booster supporting Saturday’s launch of SPHEREx and PUNCH, tail number B1088, flew for a third time. It previously flew NROL-126 for the National Reconnaissance Office and the Transporter-12 ridershare mission, which carried 131 payloads as part of SpaceX’s smallsat rideshare program.

A little less than eight minutes after liftoff, B1088 touched down back at Landing Zone 4 (LZ-4) at Vandenberg. It marked the 24th recovery at LZ-4 and the 416th successful booster landing for SpaceX to date.

Overcoming obstacles

The path to launch has not been a straightforward one for this mission. During his opening remarks on Friday, Denton Gibson, the launch director for LSP, thanked his colleagues across NASA, SpaceX, the Jet Propulsion Laboratory and the U.S. Space Force before noting that they had “run into a lot of challenges along the way.”

“A lot of those challenges have caused us some launch delays, but this team has pulled together and worked diligently to get us over that and yesterday (Thursday), we mated the spacecraft to the launch vehicle,” Gibson said.

Scheiman said that there were a “series of integration issues,” one of which involved an environmental control systems within the payload fairings called an “impedance mismatch assembly. She described it as lowering “the environments the spacecraft experiences on ascent.”

“That system has a series of inserts, 120 inserts, that during integration, we realized had become ovalized. And so, we needed to pause first, understand the issue, make sure that we had a safe path to fly,” Scheiman said. “And once we were able to do that and install updated fasteners, we then proceeded through that operation to continue that installation.”

She said while that was a large portion of the delay, that wasn’t the full picture. She said there was also an issue with the pressure within the payload fairings’ pneumatic separation system.

“Every time we perform an encapsulation operation, after that we make sure that the pressure in the fairing pneumatic system is sufficient to eventually be able to separate that fairing in flight,” Scheiman said. “And when we performed that check, this time around, after the initial encapsulation, we discovered that there was a leak in the fairing pneumatic separation system. So we needed to de-encapsulate, repair the leak and re-encapsulate.”

Scheiman said on top of those, there was also a weather delay during the period of time when they were trying to transport the encapsulated payload from the payload processing facility at Astrotech to SLC-4E.

“We don’t want to do that in high winds or bad weather and that’s what we saw the first day we were trying to do that transport,”Sheiman said. “And we were also working as on a non-interference basis for this launch with the high-priority range operation that was occurring.

“And so we did, one of those days, need to stand down to support the higher priority range operation that was happening.”

While Scheiman didn’t explicitly state what that higher priority operation was, it likely was the return from orbit of the uncrewed X-37B Orbital Transfer Vehicle, which landed back at Vandenberg on Friday morning at 2:22 a.m. EST (0722 UTC). It touched down after operating in a highly-elliptical orbit for 434 days.

Separately from everything happening in California, SpaceX was also reviewing data from a failed booster recovery following the launch of the Starlink 12-20 mission on Sunday, March 2. A fuel leak during ascent resulted in a fire breaking out in the engine section about 48 seconds after touchdown on the droneship, ‘Just Read the Instructions,’ causing the destruction of the booster.

The Federal Aviation Administration grounded the Falcon 9 rocket until March 4 as a result of the mishap. Even though NASA missions aren’t governed by the FAA, Scheiman said they still wanted to review the data and responses from that issue “to make sure that there’s no concern or risk to ascent, especially for these important science missions.”

Gibson said NASA did its own evaluation as well.

“As part of NASA Launch Services Program, one of our major roles is that we have a mission assurance role. So a lot of these evaluations, we do independent of SpaceX to give it a fresh set of eyes, a different set of eyes, to ensure that we are not incurring any risk to our mission,” Gibson said.

“And so, we’ve gone through that process and we’ve gotten comfortable, which is why we are able to complete, successfully complete our launch readiness review earlier today.”

Observing the Sun and sky

The two NASA missions onboard the Falcon 9 rocket seek to further human understanding of both the origins of the universe and of solar winds.

SPHEREx is an infrared telescope that will map the full night sky four times over the course of its planned two-year mission. Each pass will feature 102 color bands and help identify targets for other observatories, like the James Webb Space Telescope and the Wide Field Infrared Survey Telescope.

The observatory cost $488 million is managed by JPL with its principal investigator based at Caltech, which also developed SPHEREx in partnership with JPL. The spacecraft was built by Ball Aerospace (acquired by BAE Systems) and the Korea Astronomy and Space Science Institute (KASI) acts as both an instrument and science partner for the mission.

SPHEREx aims to separate from the Falcon 9 rocket about 42 minutes after liftoff and presents teams on the ground three opportunities to establish signal with the observatory.

“The first opportunity will be over Antartica. We could acquire the signal between one and three minutes after spacecraft separation,” said James Fanson, the SPHEREx project manager at JPL. “The second opportunity is 47 minutes after separation over the island of Svalbard in the Arctic. This is also our first opportunity to send a command to the spacecraft.

“The third opportunity to acquire signal is over Fairbanks, Alaska, at approximately 63 minutes after separation.”

Four days after launch, teams will open the lens cap on the telescope and then continue with outgassing of moisture and other contaminants over the following two weeks.

Besides the ejectable aperture cover, SPHEREx doesn’t feature any other moving parts or propulsion systems. Its all-aluminum telescope has a 20 cm (7.9 in) diameter and 11°x3.5° field of view

The process of calibrating the instruments, doing practice surveys and just letting the imaging sensors get cold enough will go on for roughly 37 days following launch.

Fanson said the observatory will operate in a dawn/dusk Sun-synchronous polar orbit, allowing the spacecraft to remain in sunlight. That ensures that it stays at a consistent temperature throughout its two-year mission.

He said the goal of this mission is to create a map in three dimensions of more than 400 million galaxies “across cosmic time.”

“We want to better understand what happened in the moments right after the Big Bang at the origin of the universe, when the universe is believed to have experienced a sudden, dramatic, rapid expansion called ‘cosmic inflation,” Fanson said.

Fanson said SPHEREx can also help answer the question of how much water is in the universe.

“SPHEREx will probe interstellar clouds of ices, four ices made of water and other molecules,” he said. “This mission will provide a rich archive of data that will enable many scientific studies by the astronomy community for decades to come.”

In addition to SPHEREx, four other spacecraft representing the PUNCH mission will be deployed from the Falcon 9 in pairs at roughly 52 and 53 minutes post-liftoff. It’s part of NASA’s Small Explorers (SMEX) program and cost $150 million, according to Clampin.

One of the four is a narrow field imager (NFI) coronagraph and the other three are wild field imager (WFI) heliospheric imagers. They will operate for two years following a 90-day commissioning period.

The NFI spacecraft acts as a coronagraph and has an area that blocks out the Sun to measure the corona. The three WFI spacecraft then measure the solar wind around the corona.

“We can then stitch those together and then we connect them with those images, that basically become one instrument,” said David Cheney, the PUNCH program executive. “We can then understand the three dimensional aspect of the solar wind and how it progresses as it moves towards the Earth.”

He said having that understanding can help forecasters better predict space weather and its potential impact on not only space assets, like astronauts and satellites, but also the terrestrial power grid.