Cosmic Chaos: a call for space regulation
Satellites that can become as bright as the brightest stars in the sky. It sounds like a sparkling fairy tale, but according to Marco Langbroek, these satellites, launched in 2022, will cause big problems. "Space is now becoming a bit of a wild west where anyone with enough money can do whatever they want. It's time for a sheriff to bring order to the chaos up there."
The Nature publication ‘Optical observations find high brightness of the BlueWalker 3 satellite’ was released on Monday, Oct. 2, 2023. The study, written and signed by Langbroek and 39 other experts from all over the world, discusses the brightness behavior of the prototype satellite ‘BlueWalker 3’ and its disruption to astronomical observations and the view of the night sky.
Main photo: A photo captured in 2020 by Marco Langbroek displays the trails left by a Starlink 'train,' which comprises multiple satellites launched consecutively, as indicated by the vertical stripes.
Marco Langbroek is lecturer in Optical Space Situational Awareness at the Faculty of Aerospace Engineering at TU Delft and co-author of the Nature publication ‘Optical observations find high brightness of the BlueWalker 3 satellite’ that appeared on Oct. 2, 2023.
"Space Situational Awareness involves keeping an eye on what is happening around the Earth, as well as whether space remains safe. For this we use optical instruments supplemented by special cameras and telescopes."
Why are 40 experts and researchers focusing on this very satellite?
"The BlueWalker 3 satellite is a prototype of an envisioned future network of 243 such satellites. It is very large and therefore very bright, a lot brighter than most other satellites. Astronomers are concerned about the effect of a large network of these very bright satellites on sensitive observing equipment."
What is the function of this satellite?
"With the BlueWalker 3, the company AST Space Mobile aims to enable regular cell phones to establish direct satellite connections in regions lacking reliable cell phone coverage. Because traditional cell phone signals are engineered to reach antenna masts within short distances (not a satellite at 700 km altitude), the satellite has a very large flat phased array antenna measuring 8 by 8 meters, functioning like a mirror that reflects sunlight back to Earth. This causes the satellite to reach a very high brightness. As bright as the brightest stars in the sky."
How and to what extent does this network of satellites disrupt astronomical observations?
"Hundreds of such objects in the sky can start to become a serious problem for astronomical observing programs. Right now, for example, the Vera Rubin Observatory is being built in Chile with a very large sensitive telescope that should be mapping the southern hemisphere sky every night. It is inevitable then that these satellites will be ‘seen’, and temporarily blinding the sensitive sensors of the telescope. In addition, the radio frequencies used are close to some frequencies of significance to radio astronomers, raising concerns about potential radio interference.”
“When numerous bright objects regularly traverse our skies, the appearance of our sky undergoes transformation. This transformation is already in progress. The sky is a shared heritage for all of humanity. Corporations like these are making unilateral decisions that have a big impact on our sky, all without engaging in global consultations. It's crucial to remember that the starry sky holds great cultural significance for people on Earth. It evokes romantic evenings under the stars and is interwoven with countless mythical tales. The starry sky is a natural wonder, a celestial landscape deserving of preservation. It's lamentable that in many parts of the Western world, the starry sky has become obscured from view. However, we cannot escape the pervasive 'light pollution' generated by satellite networks of this kind. Even from the most remote and darkest corners of Earth, these satellites remain visible."
What is needed to keep the space manageable?
"There is actually no legislation that deals specifically with this kind of disruption issue. Part of that has to do with the fact that creating this kind of network of hundreds or even thousands of satellites is a relatively recent development. This has caught us astronomers, as well as lawmakers, a bit off guard. Regulating international legislation through the United Nations (UN) can be a protracted process, while developments are now underway and moving very quickly. Regulation could possibly be faster through legislation at the national level in launching countries such as the United States. In our article we call for the effect on the environment (the sky and its users) to become an explicit part of launch permit procedures. In my personal view, there should also be a substantial debate on whether networks of this kind are genuinely necessary."
How can astronomers anticipate this?
"Astronomers need to proactively consider the presence of these satellites and may need to modify their observation schedules. Sometimes, they even have to temporarily deactivate instruments when one of these objects passes through their observation field. However, this relies on our ability to accurately predict when these satellites will enter the field of view of the observing instrument, and that's precisely where the challenge arises."
"Especially within these extensive satellite constellations, satellites frequently make minor orbital adjustments to maintain proper spacing and avoid collisions with other objects. This phenomenon is notable in networks like Starlink, Elon Musk's satellite constellation comprising nearly 5,000 satellites. These satellites often pass overhead at times slightly different from the initially predicted schedules. Currently, tracking such satellites relies primarily on a limited number of large and costly instruments, including telescopes and radar systems, situated in select locations worldwide. Consequently, orbital corrections are at times only detected several hours later. As a result, an object might already have shifted to a different orbit and, consequently, pass overhead at slightly different times than indicated by the most recent orbit determination."
How is TU Delft contributing to a solution?
"At TU Delft's Faculty of Aerospace Engineering, our team is working in partnership with Leiden University to develop cost-effective tracking systems that are smaller in size, allowing for their deployment in numerous locations worldwide without a substantial financial burden. This initiative is being undertaken in collaboration with the Space Department of our own Royal Air Force. By implementing these systems, we aim to enhance the real-time monitoring of satellite networks of this nature, enabling the rapid detection of orbital adjustments and the timely update of orbit databases. This, in turn, will lead to improved delivery predictions. Additionally, TU Delft is actively engaged in the design of smaller, less luminous (and therefore less disruptive) satellites."
What was your role in the publication featured in Nature?
“In the months following the launch of BlueWalker 3 a year ago, I conducted a comprehensive series of observations on the satellite using a specialized satellite-tracking camera to document its brightness patterns. These observations consistently revealed that the satellite typically exhibits high luminosity. Additionally, I utilized the same camera to perform precise positional measurements of the satellite. This allowed me to assess the accuracy of transmission predictions for this satellite, which are based on the available orbital data, and to compare them with actual observations. Such evaluations are critical in determining the safety margins that astronomers should consider when contemplating temporary instrument deactivation as a countermeasure during the satellite's passage through their observation field."
The introduction of the automobile has profoundly transformed our infrastructure, reshaping road networks, parking facilities, and traffic management systems. What does space need?
“We are in dire need of a more comprehensive and formalized system for 'Space Traffic Management.' Satellite operators and investors involved in these satellite systems must prioritize contemplating the broader risks associated with their satellites. This includes addressing concerns related to the preservation of the starry sky and minimizing disruptions to astronomers. With the rapid and unchecked expansion of extensive satellite networks, the risk of collisions is escalating, and the current practice of satellite operators resorting to telephone consultations for orbital adjustments is becoming increasingly untenable. It is imperative that we establish space traffic regulations and mechanisms for enforcing compliance. Furthermore, as previously mentioned, we must engage in a thoughtful debate regarding the necessity of these large-scale satellite networks, often comprising hundreds or even thousands of satellites. Space is now becoming a bit of a wild west, where anyone with enough money can do what they want. It's time for a sheriff to bring order to the chaos up there."