The brightness of AST SpaceMobile’s BlueWalker 3 satellite in low Earth orbit is causing concern among astronomers due to its potential impact on night sky observations. Here are some key points about this situation:

  1. Bright Satellite: BlueWalker 3, a prototype satellite launched by AST SpaceMobile in September 2022, has been observed to be exceptionally bright in the night sky. After deploying a large 64-square-meter antenna to support direct-to-device communications, the satellite’s brightness increased substantially, making it one of the brightest objects in the night sky.
  2. Magnitude Measurements: Astronomers use a magnitude scale to measure the brightness of celestial objects. BlueWalker 3’s brightness increased from magnitude 6, which is the limit of naked-eye observations in dark areas, to magnitude 0.4. This made the satellite as bright as certain prominent stars like Procyon and Achernar.
  3. Concern for Astronomy: The increase in brightness of commercial satellites like BlueWalker 3 poses challenges for astronomers. It can interfere with observations of celestial objects and impact the quality of astronomical research. Larger and brighter commercial satellites, particularly those in planned constellations, are of particular concern.
  4. Ongoing Trend: The study highlights an ongoing trend of launching larger and brighter commercial satellites. Given the plans to launch many more such satellites in the future, the potential impact on astronomy is a growing concern.
  5. Mitigation Efforts: Astronomical organizations, such as the International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS), are actively studying the impact of satellite constellations on astronomy and working on methods to mitigate these impacts.
  6. Balancing Space Activities: The situation underscores the need for a balance between space activities, including satellite deployments, and the preservation of the pristine and dark night sky that astronomers rely on for their research.

As more commercial satellites are launched into orbit, addressing their impact on ground-based astronomy remains a challenge that requires cooperation between space operators and the astronomical community to find workable solutions.

AST SpaceMobile’s response to concerns about the brightness of its satellites and their impact on astronomy involves several measures and collaboration with space and astronomy organizations:

  1. Collaboration with NASA and Astronomy Working Groups: AST SpaceMobile is collaborating with NASA and certain astronomy working groups to develop advanced industry solutions to address concerns related to the brightness of its satellites. While not directly addressing the observations in the paper, the company is actively engaging with experts in the field to find solutions.
  2. Brightness Reduction Measures: The company is working on practical methods to reduce the brightness of its satellites. This includes “roll-tilting flight maneuvers” to minimize sunlight reflection to the ground. Additionally, AST SpaceMobile plans to incorporate anti-reflective materials on its future satellites to further mitigate the issue.
  3. Comparatively Smaller Constellation: AST SpaceMobile emphasizes that its satellite constellation will be smaller in terms of the number of satellites. The company estimates that it will require only about 90 satellites to achieve substantial global coverage. In contrast, larger constellations, such as OneWeb and SpaceX, have significantly more satellites in orbit.
  4. Cooperation with Astronomical Community: Other satellite operators, like SpaceX, have also worked with astronomers to address concerns about satellite brightness. SpaceX, for instance, has taken steps to reduce the brightness of its Starlink satellites and signed coordination agreements with organizations like the National Science Foundation (NSF). The NSF is working on similar agreements with other satellite constellation operators, including Amazon and OneWeb, to ensure cooperation in mitigating the impact on astronomy.

As satellite constellations continue to expand, these efforts reflect the increasing recognition of the importance of balancing the benefits of satellite technology with the preservation of dark skies for astronomical research. Collaboration between space operators and the astronomical community is essential in finding effective solutions to this issue.

Astronomers have raised concerns not only about the optical brightness of AST SpaceMobile’s satellites but also the potential for radio astronomy interference:

  1. Radio Astronomy Interference: AST SpaceMobile’s satellites operate in frequencies allocated for terrestrial communications, which are in close proximity to the frequencies used for radio astronomy. Radio telescopes are typically situated in “radio-quiet zones” to avoid interference from terrestrial sources. However, satellite transmissions in these frequencies could potentially interfere with radio astronomy observations, even within designated radio-quiet zones.
  2. Coordination Measures: AST SpaceMobile has stated its intent to avoid broadcasting from its satellites into or near the U.S. National Radio-Quiet Zone in Virginia and West Virginia. The company also plans to avoid other radio astronomy locations as required, even if they are not officially recognized. This proactive measure is designed to minimize the potential interference with radio astronomy.
  3. Balancing Progress and Impact: Astronomers acknowledge the need for improved connectivity and internet access, especially in rural and underserved areas. However, they emphasize the importance of balancing this progress with the negative impact of bright satellites on the night sky and radio astronomy observations.

In summary, the coexistence of satellite constellations and astronomical research presents challenges, particularly in addressing issues related to optical brightness and radio frequency interference. Collaboration between satellite operators, astronomy organizations, and regulatory bodies is crucial to finding solutions that ensure both progress in satellite technology and the preservation of dark skies for astronomical research.

Comtech Telecommunications’ contract with the U.S. Army to develop the Enterprise Digital Intermediate Frequency Multi-Carrier (EDIM) modem is a significant step in advancing the capabilities of satellite communications in the military. Here are some key points to consider:

  1. Enhancing Satellite Communication: The development of the EDIM modem is aimed at enhancing the Army’s satellite communication capabilities. Modems like the EDIM are essential components of satellite communication systems, responsible for transmitting and receiving signals to and from satellites.
  2. Multi-Network Connectivity: The EDIM modem’s ability to support multiple satellite providers is crucial for the military. It enables the Army to access services that operate in different orbits and frequencies. This flexibility is important for ensuring robust and resilient communication, especially in dynamic military environments.
  3. Digitized and Hybrid Networks: The EDIM modems are designed to enable “digitized, hybrid satellite network architectures.” This indicates a shift toward more advanced and flexible network configurations that combine digital and satellite technologies. Such architectures can improve the efficiency and reliability of military communications.
  4. Replacement for Existing Modems: The EDIM modem will replace existing Enhanced Bandwidth Efficient Modems (EBEM) supplied by Viasat. This transition suggests that the Army is moving toward more advanced and capable equipment to meet its evolving communication needs.
  5. Resilient Communication Infrastructure: The EDIM modem’s support for users to roam across different carriers is a significant advantage for creating a resilient communications infrastructure. In military operations, maintaining connectivity under various conditions and in different geographic areas is crucial.
  6. Military and Defense Innovation: This contract exemplifies how the defense sector is continually adopting innovative technologies to meet its evolving requirements. Advanced satellite communication capabilities are essential for modern military operations, especially in remote or challenging environments.

The development of the EDIM modem by Comtech reflects the U.S. Army’s commitment to improving its satellite communication infrastructure, enabling better connectivity, and staying at the forefront of technological advancements in the defense sector.

The implementation of the Enterprise Digital Intermediate Frequency Multi-Carrier (EDIM) modems across various military communication systems is a significant step in enhancing communication capabilities for the U.S. Army and other military services. Here are some key points regarding this development:

  1. Integration with Terrestrial Communications: The EDIM modems are designed to integrate with terrestrial communication systems. This integration allows for seamless connectivity between satellite and ground-based communication networks, offering increased flexibility and redundancy in communication.
  2. Support Across Military Services: These modems manufactured by Comtech are intended to support satellite communication systems across the entire U.S. military, not just the Army. This unified approach ensures compatibility and interoperability among different branches of the military.
  3. Flexibility in Ground Architecture: There is a growing demand from both government and commercial customers for flexible ground architecture that can adapt to various satellite orbits, constellations, and waveforms. The EDIM modems are expected to address these evolving requirements.
  4. Transition from EBEM Modems: The EDIM modems will replace the existing Enhanced Bandwidth Efficient Modems (EBEM) currently deployed. Tens of thousands of EBEM modems are in use and are expected to be replaced gradually. This transition to more advanced equipment will provide enhanced communication capabilities.
  5. Fixed and Tactical Systems: The implementation of EDIM modems will extend to both fixed and tactical systems. Fixed sites, such as U.S. Army regional hub nodes and Defense Information Systems Agency facilities, will see the replacement of existing modems. Similarly, tactical systems used in forward-deployed satcom infrastructure will also be upgraded.
  6. Future Flexibility: The timeline and scale of the upgrade to EDIM modems will depend on individual organizations within the military services. They will decide when and how to implement the new modems based on their specific needs and existing infrastructure.

Overall, the adoption of EDIM modems by Comtech is part of an ongoing effort to modernize and enhance military communication infrastructure, ensuring that the U.S. military can maintain secure, reliable, and flexible communication capabilities across different scenarios and environments.


The development of a new, large, and reusable launch vehicle marks a significant step in Japan’s ambitious space exploration endeavors. This project, undertaken collaboratively by JAXA and MHI, is a response to the evolving landscape of space exploration. As space missions become more complex and frequent, there is a growing demand for versatile and cost-effective launch systems that can adapt to a wide range of payloads and mission profiles.

The initiative, backed by Japan’s revised space policy, reflects a forward-looking vision. This vision encompasses not only achieving cost savings and improving launch efficiency but also contributing to environmental sustainability. Reusable launch vehicles hold the promise of reducing space debris and lowering the environmental impact of space exploration.

As space exploration enters an exciting phase with missions to the Moon, Mars, and beyond, Japan is positioning itself as a key player in this global endeavor. The new rocket, which builds on the advancements of the H3, aims to increase satellite capacity, making it more versatile for various mission requirements. Moreover, by incorporating reusability, Japan seeks to drive down the costs associated with space missions, making space more accessible and affordable for scientific research, commercial ventures, and international collaboration.

While the new rocket’s design and development are still in their early stages, it represents Japan’s commitment to pushing the boundaries of space exploration. The collaboration between JAXA and MHI, both renowned for their contributions to space technology, underscores Japan’s intention to remain at the forefront of space exploration and contribute to a more sustainable and efficient future for space transportation. As this project progresses, it holds the potential to open new possibilities for international cooperation in space exploration and research.

The consideration of fuel options, such as liquid methane and liquid hydrogen, for the new rocket underscores the evolving landscape of space exploration technologies. Liquid methane, in particular, has gained prominence as an environmentally friendly and cost-effective propellant choice for rocket engines. The interest in methane propulsion aligns with global trends observed in the United States and China, where both government agencies and commercial firms have been working on methane-liquid oxygen launchers.

JAXA has a goal of reducing the cost per kilogram to low Earth orbit (LEO) by about half compared to the H3 rocket reflects a broader industry objective of driving down launch costs. Achieving this cost reduction will not only make space access more affordable but will also facilitate an increase in launch frequency, accommodating a more diverse array of space missions.

While specific details about the new rocket’s design and capabilities remain in development, its intended purpose is clear: to transport cargo vehicles to lunar orbit and landers to the moon’s surface. This lunar capability is particularly significant, aligning with the global push for lunar exploration, including NASA’s Artemis program and other international lunar missions.

The new rocket, anticipated to be ready for the 2030s, presents an exciting opportunity for Japan to play a pivotal role in lunar exploration and potentially support human spaceflight endeavors in the future. By leaving space for private space companies to contribute to Japan’s space transportation capabilities, the plan promotes innovation, fostering a competitive environment and driving advancements in space technology.

As the global space sector continues to expand, these developments align Japan with the international community’s shared aspirations for scientific research, exploration, and commercial ventures in space. Collaboration and partnerships are at the heart of this vision, with both public and private entities contributing to the future of space transportation and exploration.

MediaTek, a Taiwanese chipmaker and Inmarsat, a British satellite operator have announced an extended partnership aimed at jointly developing technologies that will enable more mass-market devices to connect directly to Inmarsat’s satellite network. This expanded collaboration will not only focus on joint technology innovation but also encompass the commercial deployment of satellite-enabled devices, potentially spanning smartphones, Internet of Things (IoT) devices, and even vehicles.

The services to be offered through this partnership could include two-way text messaging, emergency communications, and device tracking and monitoring for regions where terrestrial network coverage is limited or unavailable. However, there is currently no specific deadline for when these satellite-enabled devices will be commercially deployed as a result of this partnership.

In the case of smartphones, for instance, the approach will involve working closely with Mobile Network Operators (MNOs) and Original Equipment Manufacturers (OEMs) to integrate satellite connectivity into their offerings. This ensures that the integration aligns with the strategies and preferences of MNOs and OEMs, allowing them to provide enhanced services to their customers.

This collaboration builds upon a three-year partnership that had already yielded significant results. In February, the partnership led to the release of Android smartphones by ruggedized handset manufacturer Bullitt, which provided satellite-enabled text messaging services via service provider Skylo. With this expansion, Inmarsat and MediaTek aim to further innovate and expand the reach of satellite connectivity across various consumer and industrial applications.

The partnership between Inmarsat and MediaTek comes on the heels of other satellite operators venturing into the realm of enabling mass-market devices to connect directly to their networks. Iridium, for instance, announced Qualcomm as its partner to facilitate the connection of Android smartphones and other devices to its satellite constellation.

Furthermore, Apple introduced a satellite-enabled SOS service for the iPhone 14, using Globalstar’s network. It’s important to note that while Iridium and Globalstar operate in low Earth orbit (LEO), Inmarsat’s satellites are situated in geostationary orbit (GEO). This key distinction means that Inmarsat can provide two-way communications without the need for complex aiming of the device. However, it’s worth mentioning that Iridium and Globalstar enjoy an advantage in terms of latency since LEO satellites are much closer to Earth than GEO satellites.