A second SpaceX attempt to launch the gigantic Starship spacecraft, insights into the formation of black holes, the impact of radiation bursts on Earth’s atmosphere, U.S oversight of private space enterprises. This Week in Space

Starship: Take 2

SpaceX has received approval from the United States Federal Aviation Administration (FAA) for a second launch trial of the Starship spacecraft from their South Texas space facility. The launch attempt was scheduled for Friday, November 17, within a two-hour launch window starting at 7:00 AM local time. The FAA's announcement emphasized that SpaceX has met all the requirements related to safety, environmental conservation, and responsible economic conduct.

This approval comes after months of discussions and corrections of issues identified in April's failed launch attempt, in which the spacecraft didn't separate from its booster and was destroyed by a controlled explosion over the Gulf of Mexico to avoid further complications. SpaceX was tasked with rectifying various defects, including a delay in the activation of the detonation that risked a lower-altitude explosion, posing environmental risks. The launch pad also suffered damage in the previous launch, with debris being scattered over a considerable distance. SpaceX has diligently addressed dozens of defects and issues to ensure safer and more environmentally-friendly future launches.

The launch experiment on Friday was designed to take place in a similar framework to that planned in the previous launch attempt: after the separation of the spacecraft from the launch missile, called "Super Heavy," the missile was designed to perform a landing maneuver, this time into the sea, without a controlled landing attempt. The unmanned spacecraft was set to complete a partial orbit of Earth at an altitude of 250 kilometers, re-enter the atmosphere over Hawaii, and execute a landing maneuver, ultimately ending in a sea landing. In future missions, the spacecraft is supposed to perform a soft vertical landing, with plans for an immense landing tower equipped with special arms designed to gently secure and place the landing spacecraft on the ground.

 We hope that this time the experiment will not end in an explosion. The Starship spacecraft and the Super Heavy launch missile on the launch pad before the previous experiment, April 2023 | Photo: SpaceX

Starship is an immense spacecraft designed by SpaceX for ambitious deep-space missions. Paired with the colossal Super Heavy rocket, this dynamic duo boasts impressive specifications. The Super Heavy, standing at a towering 69 meters tall and with a nine-meter diameter, is powered by 33 robust Raptor engines. Mounted atop it is the 50-meter-tall Starship, sharing the same nine-meter diameter, and equipped with six Raptor engines that provide essential maneuverability in the vast expanse of space.

This spacecraft has a remarkable payload capacity, capable of transporting approximately 150 tons of cargo – a staggering three times more than the Saturn V rocket that famously launched the Apollo missions to the moon. Despite their relatively heavy stainless steel construction, both the spacecraft and the rocket are engineered for rapid readiness in multiple launches. Furthermore, to ensure safe reentry into Earth's atmosphere, the Starship is equipped with a heat shield composed of durable ceramic tiles.

The Starship spacecraft is not only designed for cargo but also intended for human missions. Elon Musk, the owner and president of SpaceX, harbors an ambitious dream of utilizing a substantial fleet of these spacecraft to establish a human settlement on Mars. This is also one of the reasons why the spacecraft and the missile are powered by methane (CH4) and oxygen (O2) - gases that can be produced from Mars’ atmosphere. Additionally, NASA has selected Starship as the lunar landing vehicle for the Artemis program, aimed at returning humans to the Moon. This mission is expected to take place, most likely, in 2026 and will necessitate the utilization of other Starship spacecraft as in-space refueling vehicles. 

This pivotal space experiment was broadcast live on SpaceX's YouTube channel, along with various other space enthusiasts' platforms.

The Peculiar Flashes Following the Supernova

In September 2022, astrophysicists witnessed a formidable star explosion in a galaxy situated extremely far from us, about four billion light-years away. This event, designated as AT2022tsd, was not a typical supernova, belonging instead to a much rarer category of cosmic explosions. These unique phenomena, known as "Luminous Fast Blue Optical Transients" (LFBOTs), exhibit a notably brief lifespan lasting only a few days, in stark contrast to the weeks or months typical of regular supernovae. Additionally, LFBOTs emit a substantial amount of blue light.

As researchers know very little about these types of cosmic explosions, they try to investigate them in-depth. Dr. Ping Chen, a postdoctoral fellow at the Weizmann Institute of Science, embarked on such an in-depth investigation. Chen used observation time on the European "Magellan" telescope in Chile to study the remnants of the explosion 100 days after its initial discovery. Due to technical reasons, he divided his observation time into relatively short exposures lasting only a few minutes each. When he examined the images, he was surprised to find very bright flashes of light—much stronger than expected this long after the LFBOT initially occurred.

"Until now, we didn't exactly know what causes star explosions of this type," Chen told the Davidson Institute website. "Now, thanks to this discovery, we are almost certain that such an explosion creates a black hole or a neutron star, which reabsorbs some of the material ejected in the explosion, causing the light flashes." Following the discovery, Chen and his colleagues closely monitored AT2022tsd using, among other tools, the Weizmann Institute's newly established telescope array in Neot Smadar, found in the Arava region. "Since the initial discovery was by chance, we started to look for such light flashes proactively. We identified more flashes in observations of the same LFBOT, but we do not know if they also exist in other explosions of this type. They might, but we simply haven't seen them until now," said Chen. "Now we are trying to look for such flashes around other recently identified LFBOT explosions."

"This is the first time such a thing has been seen, and it can help us understand the mechanism of such explosions," explains Professor Eran Ofek from the Department of Astrophysics at the Weizmann Institute of Science, a co-author of the research paper, together with Chen and other researchers from the institute: Sagi Ben-Ami, Avishay Gal-Yam, David Polishook, and Enrico Segre, alongside a long list of scientists from around the world. "There are many types of star explosions, and there are many open questions regarding their explosion mechanisms. One of the questions is what remains after the explosion. After we ruled out the possibility that the flashes are from another source, and after we identified more such flashes, the conclusion is that there remains an active object that begins to emit energy. It's probably a black hole absorbing matter, but it could also be neutron stars, or even a binary system of two celestial bodies. To understand this, we are now looking for more such supernovae, and also looking for the phenomenon in other types of supernovae."

In just over two years, NASA is expected to launch the Israeli space telescope ULTRASAT, developed at the Weizmann Institute of Science. The telescope will scan the skies for rapid events that emit ultraviolet radiation and will allow other ground-based and space telescopes to target such events in real-time. "This is precisely the type of event that ULTRASAT is poised to help us discover," says Ofek, a member of the telescope's research team

 The brief flashes long after the explosion could teach us about what remains behind. Visualization of an LFBOT-type star explosion | Source: NASA, ESA, NSF's NOIRLab, Mark Garlick, Mahdi Zamani

The Explosion That Shakes the Atmosphere

Another study on a far-off space explosion reveals that, despite its immense distance from Earth, the radiation it emitted affected Earth's atmosphere, temporarily altering its electrical fields.

The explosion in question was a gamma-ray burst detected in October 2022, which occurred 2.4 billion light-years from us and was one of the most powerful ever recorded. A large team of researchers, led by scientists from Italy, examined how the radiation from this burst affected Earth's ionosphere. The ionosphere is one of the atmospheric layers characterized by the abundance of free electrons, a result of intense solar radiation, such as gamma and X-rays, which dislodges electrons from gas atoms found within this layer, thereby turning the atoms into ions. The ionosphere, which overlaps with several other atmospheric layers, starts at about 50 kilometers above the Earth's surface and extends to about 1,000 kilometers—an area that is effectively already within the realm of outer space.

Until now, the effects of such distant radiation bursts on the atmosphere had not been examined, and this time the researchers decided to investigate it. While the radiation's effects on the electrical conductivity of the lower ionosphere can be measured using ground antennas, the great challenge is actually measuring the impact on the higher parts of the ionosphere, which are already situated in space. To tackle this challenge, the researchers monitored changes in satellite communication at the moment the burst was detected on Earth, revealing significant alterations in the ionosphere's conductivity at an altitude of about 500 kilometers.

The researchers also found that although the burst was only measured for seven minutes, its impact on the ionosphere's conductivity lasted about ten hours. They believe that a better understanding of the impact of such a burst on the upper atmosphere will help us understand the impacts of closer radiation bursts on our atmosphere and activities within it, such as satellite communications, and also to prepare for it accordingly.

he gamma-ray burst GRB 221009A detected in October 2022 and captured by the Hubble Space Telescope. The circled burst appears less luminous than other stars, but it is much further away from us | Photo: NASA, ESA, CSA, STScI, A. Levan (Radboud University); Image Processing: Gladys Kober

Expanding Government Regulation

The U.S. federal government is advancing a proposal to increase federal regulation of novel commercial space activities, including activities that have not been subject to such oversight until now. According to the proposed legislation, developed by the National Space Council, led by Vice President of the United States Kamala Harris, this oversight will not be consolidated under a single agency but the responsibility will be split between the Commerce and Transportation departments, both of which are already involved in space-related matters to some extent.

The Department of Transportation currently oversees launches and returns of rockets, spacecraft, and satellites through the Federal Aviation Administration - hence SpaceX's need for its approval for the Starship trial. According to the new proposal, this oversight will expand to cover all private company activities in space, including the operation of commercial space stations, lunar flights, and the transfer of supplies or equipment to space, as well as flights to other celestial bodies.

The Office of Space Commerce, which currently handles commercial remote sensing regulations, will also expand its oversight and will be responsible for activities not regulated by the Department of Transportation (DOT), such as in-space servicing and maintenance of satellites, plans for assembly and manufacturing in space, and space debris removal. Additionally, the office will receive oversight of space traffic management from the Defense Department, focused on preventing collisions between satellites and spacecraft.

Although both departments expressed support for the proposed legislation, as did other institutions, including NASA, it already faced its first setback when the Science Committee of the House of Representatives postponed the discussion on the subject until after the Thanksgiving holiday, about a week from now. The main reason for the postponement is a demand from Republicans to amend certain sections of the law to align with a proposal they themselves submitted on the subject.

 According to the new law, commercial companies will need to obtain a license from the Department of Transportation to set up a private space station. The future Orbital Reef space station planned by Blue Origin| Source: Blue Origin