Study Findings: Satellite Megaconstellations will Threaten Space-based Astronomy

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Image (Credit): The Hubble Space Telescope. (NASA)

Nature abstract of the study findings:

Rapidly growing satellite constellations have raised strong concerns among the scientific community. Reflections from satellites can be visible to the unaided eye and extremely bright for professional telescopes. These trails already affect astronomical images across the complete electromagnetic spectrum, with a noticeable cost for operations and mitigation efforts. Contrary to popular perception, satellite trails affect not only ground-based observatories but also space observatories such as the Hubble Space Telescope. However, the current number of satellites is only a fraction (less than 3%) of those to be launched in the next decade. Here we show a forecast of the satellite trail contamination levels for a series of international low-Earth-orbit telescopes on the basis of the proposed telecommunication industry constellations. Our results show that if these constellations are completed, one-third of the images of the Hubble Space Telescope will be contaminated, while the SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer), ARRAKIHS (Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys) and Xuntian space telescopes will have more than 96% of their exposures affected, with 5.6,  69 and 92 trails per exposure, respectively, with an average surface brightness of μ = 19 ± 2 mag arcsec−2. Our results demonstrate that light contamination is a growing threat for space telescope operations. We propose a series of actions to minimize the impact of satellite constellations, allowing researchers to predict, model and correct unwanted satellite light pollution from science observations.

Citation: Borlaff, A.S., Marcum, P.M. & Howell, S.B. Satellite megaconstellations will threaten space-based astronomy. Nature 648, 51–57 (2025).

https://doi.org/10.1038/s41586-025-09759-5

Study-related stories:

Scientific American – “Satellites Swarming Low-Earth Orbit Threaten Space Telescopes”

News Scientist – “Planned Satellite Launches Could Ruin Hubble Space Telescope Images”

Orbital Today – “Satellite Boom Set To Disrupt Space Telescopes As Researchers Warn Of ‘Growing Threat’”

Space Quote: British Satellite to Study Impact of Stars on Exoplanets

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Credit: Blue Skies Space

“Mauve will open a new window on stellar activity that has previously been largely hidden from view…By observing stars in ultraviolet light, wavelengths that can’t be studied from Earth, we’ll gain a much deeper understanding of how stars behave and how their flares may impact the environment of orbiting exoplanets. Traditional ground-based telescopes just can’t capture this information, so a satellite like Mauve is crucial for furthering our knowledge.”

–Statement by Professor Giovanna Tinetti, Chief Scientist and Co-founder of Blue Skies Space, regarding today’s launch of the Mauve cubesat satellite. This satellite contains a 13 cm telescope that will be used to observe hundreds of stars in the ultraviolet and visible wavelengths over a three-year period. Data from this mission will be sold via subscriptions, and used to study the stars and how their activity influences the habitability of distant exoplanets. You can find more information on the mission here.

Space Quote: It’s Raining Satellites

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Credit: Image by Mohamed Hassan from Pixabay.

“Jonathan McDowell, an astronomer at the Harvard–Smithsonian Center for Astrophysics in the US, recorded an average of between one to two Starlink satellites deorbiting each day in 2025. That figure is expected to rise to around five per day as SpaceX continues to grow its space internet constellation.”

-Statement in the UK’s Independent newspaper regarding SpaceX’s Starlink satellites burning up in the Earth’s atmosphere. Given that the satellites are only expected to last 5 years and there are already 8,500 in orbit, this should come as no surprise. Fortunately, the satellites are designed to burn up after their useful life space. Of course, that does not necessarily mean that burning debris and the related pollutants are welcome. It will only get worse once Amazon and China start pumping even more satellites into orbit.

The X37-B Mini-Shuttle Returns to Orbit

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Image (Credit): The X37-B space plane. (US Space Force)

While the space shuttles are all safely stored in space museums around the country, the U.S. Space Force’s X37B space plane (or uncrewed mini-shuttle) is still in business.

The spacecraft returned to Earth orbit late last week, launched from the Kennedy Space Center. The X-37B can stay in orbit for multiple years, powered by both batteries and solar cells. The latest launch is the eighth such mission.

While the missions are generally classified, they are thought to be basic experiments to enhance the U.S. Space Forces capabilities. For example, the latest mission is testing a quantum navigation sensor that can detect a spacecraft’s location without GPS. Of course, other have said the spacecraft are spying on the Chinese space station and Russian satellites. It is certainly possible that the little shuttle has been busy with all of this.

The two X-37Bs, called autonomous, reusable orbital test vehicles, were built by Boeing and started flying in 2010, one year before the end of the crewed space shuttles servicing the International Space Station (ISS).

It is odd that Boeing has done so well with this shuttle yet so poorly getting a manned capsule safely to and from the ISS, but maybe it has more to do with the skills of Rockwell International, which build the manned shuttles and was later acquired by Boeing.

Space Stories: White House Destroys Satellite, US Nuclear Reactor Proposed for the Moon, and the End of the Lunar Trailblazer Mission

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Here are some recent space-related stories of interest.

—Oregon Public Radio: “Why a NASA Satellite that Scientists and Farmers Rely On May Be Destroyed on Purpose“

The Trump administration has asked NASA employees to draw up plans to end at least two major satellite missions, according to current and former NASA staffers. If the plans are carried out, one of the missions would be permanently terminated, because the satellite would burn up in the atmosphere. The data the two missions collect is widely used, including by scientists, oil and gas companies and farmers who need detailed information about carbon dioxide and crop health. They are the only two federal satellite missions that were designed and built specifically to monitor planet-warming greenhouse gases.

—CNN: “NASA Wants US to be the First Nation to Put Nuclear Reactor on the Moon“

Acting NASA Administrator Sean Duffy has directed the agency to fast-track plans to put a nuclear reactor on the moon. Expediting work to place a reactor on the lunar surface to help power moon exploration efforts would keep the United States ahead of China and Russia, both of which have “announced on at least three occasions” a joint effort to develop such a project by the mid-2030s, according to a directive dated July 31 and obtained by CNN.

—NASA: “NASA’s Lunar Trailblazer Moon Mission Ends“

NASA’s Lunar Trailblazer ended its mission to the Moon on July 31. Despite extensive efforts, mission operators were unable to establish two-way communications after losing contact with the spacecraft the day following its Feb. 26 launch. The mission aimed to produce high-resolution maps of water on the Moon’s surface and determine what form the water is in, how much is there, and how it changes over time. The maps would have supported future robotic and human exploration of the Moon as well as commercial interests while also contributing to the understanding of water cycles on airless bodies throughout the solar system.