Every night, thousands of satellites compete with the stars in the sky. As constellations of satellites multiply, the number of intruders will only increase. Companies plan to launch orbiters at a rate of tens or hundreds of thousands of them to transmit internet signals and other communication signals back to Earth. SpaceX has launched thousands of Starlink Satellites and Amazon plans to launch its Project Kuiper constellation this year.
This is a growing problem for astronomers who study the universe on the surface of the earth.
Eric Burns is an astronomer from Louisiana State University. "It's hot," he said. We're dealing with a number of satellites that is so large, they limit the sensitivity for ground-based telescopes.
Many astronomers have expressed strong criticisms about the effects of satellite constellations, both present and future, on their research. Dr. Burns, along with other scientists, are considering how to make cosmic lemonade from orbital lemons. What if all those satellites that interfere with each other could actually help the field of Astronomy by expanding access to satellite signals on the ground?
These astronomers are interested in the possibility of a new telescope, which mega-constellations may provide. Dr. Burns' and his co-workers hope to send thousands of tiny gamma ray detectors into space along with satellites in a proposal they will soon share with private companies that are building constellations. Each detector, taken alone, would be weak. When a constellation of thousands of satellites is used, this system can rival the Swift and Fermi observatories, which are both managed by NASA.
The impact would be substantial. Gamma-ray explosions are the hallmarks of the universe's biggest catastrophic events since Big Bang. Research into this phenomenon could answer some of today's most important questions, including what the neutron star cores are made of or how dark energy can reveal the shape and size of the universe.
Burns stated that these questions are among the most important in astronomy. "We will have the ability to use thousands of gamma ray detectors in a coherent, powerful telescope that can look at the entire universe. This would be more sensitive than any previous work."
This idea has been tried before. Iridium Communications and scientists partnered in 2011 to launch research instruments into orbit. Around 30 Iridium Satellites, which transmit voice and data communications to Earth, also house dosimeters for measuring radiation in low Earth orbit as part of the REACH Program. This is a collaboration by the United States Air Force with scientists.
All 60 satellites of Iridium are equipped with magnetometers that will be used by the AMPERE Program, run by Johns Hopkins Applied Physics Laboratory. This program studies the energy entering the Earth's ionosphere and magnetosphere.
Alexa Halford is an associate lab chief in NASA's Goddard Space Flight Center. She says that Iridium readings provide important radiation data. Her research reveals the relationship between Earth's atmosphere and magnetosphere, and how they work together to protect the ground against strong radiation showers from space.
Dr. Halford stated that it was important to consider the way in which mega-constellations on satellites interfere with telescopes at Earth's surface.
She said, "Ground-based Astronomy is extremely important and we must be responsible."
She sees great potential in putting more scientific instruments on satellites.
"More information can help us get a better picture," said Dr. Halford. "It would be hard for me to say no."
SpaceX already shares some data with scientists, which could be beneficial to both.
Tzu-Wei Fang is a space weather expert at the National Oceanic and Atmospheric Administration. She began working with SpaceX in February 2022 after a disastrous launch. SpaceX was forced to watch as 38 out of 49 newly deployed Starlink Satellites caught fire.
In his post-mortem, Dr. Fang documented that a minor geomagnetic disturbance had increased the density of air at altitudes near low-Earth orbits. Instead of sailing into space, the Starlink satellites hit dense, hot air, and broke apart.
She said, "We don't currently have the satellites to do low-Earth-orbit drag well."
After this incident, SpaceX decided to share for one year the data on the positions and speeds of its roughly 4,000 Starlink satellites, giving Dr. Fang's colleagues the chance to study the type orbital drag which had destroyed the satellites. This could lead to improved space weather forecasts, as satellites would have more time to react if there was a sudden increase in air density.
Technical hurdles are involved in obtaining scientifically useful information from satellite constellations. Satellites in low Earth orbit are very fast and complete an orbital cycle in about 90 minutes. Combining data from many satellites can be difficult.
There are also strict restrictions on the scientific equipment that can be launched into orbit. The detectors for low-Earth orbit communications satellites like SpaceX Starlink have a short lifespan of five years. The Hubble Space Telescope, on the other hand, cost about $16 billion today but is expected last for around 40 years.
Additions could not be made at the last moment. Satellite engineers will need to adapt their designs in order to accommodate new payloads, such as upgrades like bigger power sources and better data links.
Scientists will not be helped by gamma ray detectors, or any other sensors, if they are building huge satellite constellations. SpaceX refused to comment, while OneWeb, who recently completed a smaller constellation, did not respond. Project Kuiper is the constellation of the online retailer Amazon, which may launch its satellites this year. Dr. Burns was invited to submit a proposal.
Dr. Halford said that increasing the partnerships with constellation operators would benefit all parties without clogging up the skies. She said, "It's not the best answer but it's all we have."
Astronomers have been frustrated by the difficulty of negotiating individually with companies such as SpaceX. Dr. Burns believes it's time to have government oversight in order to minimize the harm caused by mega-constellations to science.
Dr. Burns believes that scientists and satellite manufacturers can work better together with greater participation. He said that he thought the idea of placing science instruments on mega-constellations would benefit both sides. "If they are open to it, then it is an even better solution."