Milky Way’s brightest gamma-ray binary system may be powered by a magnetar star

Gamma-ray binaries are a system of massive, high-energy stars and compact stars. They appear bright bluish-white stars when observing with visible light. When observing X-rays and gamma-rays, their properties differ drastically from those of other binaries. Once the gamma-ray binaries were established as a new astrophysical class, it was quickly recognized that an extremely efficient acceleration mechanism should operate in them. Some gamma-ray binaries are known to emit strong gamma-rays with energies of several megaelectron volts (MeV). Such gamma rays are quite challenging to observe as they were detected from only around 30 celestial bodies in the whole sky. But, what’s mysterious is that such binaries emit strong radiation even in this energy band. This means a beneficial particle acceleration process must be going on within them. The past few studies made it clear that a gamma-ray binary is generally made of a massive primary star that weighs 20-30 times the Sun’s mass and a companion star that must be compact. But, it remains unclear whether the close star is a black hole or a neutron star. Scientists at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) have studied previously collected data to infer the nature of a magnetar orbiting within LS 5039, the brightest gamma-ray binary system in the Galaxy. Scientists focused on LS 5039 because of its position as the brightest gamma-ray binary in the X-rays and gamma-ray range.

Earlier, it was thought that the LS 5039 must have a neutron star because of its stable X-ray and TeV gamma-ray radiation. However, until now, attempts to detect such pulses had been conducted with radio waves and soft X-rays—and because radio waves and soft X-rays are affected by the primary star’s stellar winds, detection of such periodical pulses had not been successful.

Now, for the first time, scientists focused on the hard X-ray band (>10 keV) and observation data from LS 5039 gathered by the hard X-ray detector (HXD). The data was collected from the space-based telescopes Suzaku (between September 9 and 15, 2007) and NuSTAR (between September 1 and 5, 2016).

Both observations provided evidence on the presence of a neutron star within the core of LS 5039:the periodic signal from Suzaku with a period of about 9 seconds. The probability that this signal arises from statistical fluctuations is only 0.1 percent. NuSTAR also showed a very similar pulse signal. Combining these results also inferred that the spin period is increasing by 0.001 s every year.

Based on the derived spin period and the rate of its increase, the group precluded the rotation powered and accretion- powered scenarios. They found that the neutron star’s magnetic energy is the sole energy source that can power LS 5039.

The required magnetic field reaches 1011 T, three orders of magnitude higher than those of typical neutron stars. This value is found among so-called magnetars, a subclass of neutron stars with such a powerful magnetic field.

The pulse period of 9 seconds is typical of magnetars. This strong magnetic field prevents the primary star’s stellar wind from being captured by a neutron star, explaining why LS 5039 does not exhibit properties similar to X-ray pulsars.

Strangely, the 30 magnetars that have been found so far have all been seen as isolated stars, so their existence in gamma-ray binaries was not viewed as a standard idea. Other than this new theory, the group recommends a source that powers the non-thermal emission inside LS 5039—they suggest that the emission is caused by a collaboration between the magnetar’s magnetic fields and dense stellar winds. Indeed, their figurings recommend that gamma-rays with energies of several megaelectronvolts, which has been unclear, can be unequivocally emitted if they are produced in a region of a powerful magnetic field, close to a magnetar.

These results potentially settle the mystery of the compact object’s nature within LS 5039 and the underlying mechanism powering the binary system. However, further observations and refining of their research are needed to shed new light on their findings.

Gilmour Space and Northrop Grumman sign MoU to Grow Sovereign Capabilities in Australia

Australian rocket company, Gilmour Space Technologies, has signed a Memorandum of Understanding (MOU) with global aerospace giant Northrop Grumman Corporation to work on developing sovereign space capabilities in Australia. "Northrop Grumman aims to lead industry support in developing Australian sovereign space capabilities to help meet the needs of defence and realise the Australian Space Agency vision," said Chris Deeble, chief executive, Northrop Grumman Australia. "Our approach is consistent with the Australian government's recently announced Modern Manufacturing Strategy, to make space hardware in Australia while securing sovereign capabilities in priority areas that includes defence and space." As an initial task under the MOU, Northrop Grumman will join Gilmour Space as an industry partner on a previously announced Cooperative Research Centre Project (CRC-P) to develop composite rocket tanks for low-cost space transport. The CRC-P, which includes Griffith University and Etamax Engineering, will manufacture composite tanks up to two metres in diameter and trial them in rocket flights, in an effort to reduce weight and increase reliability. Gilmour Space CEO Adam Gilmour said the company is excited to work with Northrop Grumman on this opportunity. "It is great to gain the support of Northrop Grumman who, through this investment, have further demonstrated their commitment to grow Australian space capability."

The next five years will be a critical time for Australia to develop a world-class sovereign space industry.

"With the right support, we will see innovative, well capitalised, and highly capable Australian space companies like Gilmour Space emerge as future Australian space primes. We look forward to working with Northrop Grumman as we work to launch our first commercial payloads to orbit in 2022."

US-European mission launches to monitor the world's oceans

A joint U.S.-European satellite built to monitor global sea levels lifted off on a SpaceX Falcon 9 rocket from Space Launch Complex 4E at Vandenberg Air Force Base in California Saturday at 9:17 a.m. PST (12:17 p.m. EST). About the size of a small pickup truck, Sentinel-6 Michael Freilich will extend a nearly 30-year continuous dataset on sea level collected by an ongoing collaboration of U.S. and European satellites while enhancing weather forecasts and providing detailed information on large-scale ocean currents to support ship navigation near coastlines. "The Earth is changing, and this satellite will help deepen our understanding of how," said Karen St. Germain, director of NASA's Earth Science Division. "The changing Earth processes are affecting sea level globally, but the impact on local communities varies widely. International collaboration is critical to both understanding these changes and informing coastal communities around the world." After arriving in orbit, the spacecraft separated from the rocket's second stage and unfolded its twin sets of solar arrays. Ground controllers successfully acquired the satellite's signal, and initial telemetry reports showed the spacecraft in good health. Sentinel-6 Michael Freilich will now undergo a series of exhaustive checks and calibrations before it starts collecting science data in a few months' time.

Continuing the Legacy
The spacecraft is named in honor of Michael Freilich, the former director of NASA's Earth Science Division, who was a leading figure in advancing ocean observations from space. Freilich passed away Aug. 5, 2020. His close family and friends attended the launch of the satellite that now carries his name.

"Michael was a tireless force in Earth sciences. Climate change and sea level rise know no national borders, and he championed international collaboration to confront the challenge," said ESA (European Space Agency) Director of Earth Observation Programmes Josef Aschbacher. "It's fitting that a satellite in his name will continue the 'gold standard' of sea level measurements for the next half-decade. This European-U.S. cooperation is exemplary and will pave the way for more cooperation opportunities in Earth observation."

"Mike helped ensure NASA was a steadfast partner with scientists and space agencies worldwide, and his love of oceanography and Earth science helped us improve understanding of our beautiful planet," added Thomas Zurbuchen, NASA associate administrator for science at the agency's headquarters. "This satellite so graciously named for him by our European partners will carry out the critical work Mike so believed in - adding to a legacy of crucial data about our oceans and paying it forward for the benefit of future generations."

Sentinel-6 Michael Freilich will continue the sea level record that began in 1992 with the TOPEX/Poseidon satellite and continued with Jason-1 (2001), OSTM/Jason-2 (2008), and eventually Jason-3, which has been observing the oceans since 2016. Together, these satellites have provided a nearly 30-year record ofprecise measurements of sea level height while tracking the rate at which our oceans are rising in response to our warming climate. Sentinel-6 Michael Freilich will pass the baton to its twin, Sentinel-6B, in 2025, extending the current climate record at least another 10 years between the two satellites.

Global Science Impact
This latest mission marks the first international involvement in Copernicus, the European Union's Earth Observation Programme. Along with measuring sea levels for almost the entire globe, Sentinel-6 Michael Freilich's suite of scientific instruments will also make atmospheric measurements that can be used to complement climate models and help meteorologists make better weather forecasts.

"NASA is but one of several partners involved in Sentinel-6 Michael Freilich, but this satellite speaks to the very core of our mission," said NASA Administrator Jim Bridenstine. "Whether 800 miles above Earth with this remarkable spacecraft or traveling to Mars to look for signs of life, whether providing farmers with agricultural data or aiding first responders with our Disasters program, we are tirelessly committed not just to learning and exploring, but to having an impact where it's needed."

The initial orbit of Sentinel-6 Michael Freilich is about 12.5 miles (20.1 kilometers) lower than its ultimate operational orbit of 830 miles (1,336 kilometers). In less than a month, the satellite will receive commands to raise its orbit, trailing Jason-3 by about 30 seconds. Mission scientists and engineers will then spend about a year cross-calibrating data collected by the two satellites to ensure the continuity of sea level measurements from one satellite to the next. Sentinel-6 Michael Freilich will then take over as the primary sea level satellite and Jason-3 will provide a supporting role until the end of its mission.

"This mission is the very essence of partnership, precision, and incredible long-term focus," said Michael Watkins, director of NASA's Jet Propulsion Laboratory in Southern California, which manages the mission. "Sentinel-6 Michael Freilich not only provides a critical measurement,it is essential for continuing this historic multi-decadal sea level record."

Sentinel-6 Michael Freilich and Sentinel-6B compose the Sentinel-6/Jason-CS (Continuity of Service) mission developed in partnership with ESA. ESA is developing the new Sentinel family of missions to support the operational needs of the Copernicus program, managed by the European Commission. Other partners include the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and National Oceanic and Atmospheric Administration, with funding support from the European Commission and technical support from France's National Centre for Space Studies.

"The data from this satellite, which is so critical for climate monitoring and weather forecasting, will be of unprecedented accuracy," said EUMETSAT Director-General Alain Ratier. "These data, which can only be obtained by measurements from space, will bring a wide range of benefits to people around the globe, from safer ocean travel to more precise prediction of hurricane paths, from greater understanding of sea level rise to more accurate seasonal weather forecasts, and so much more."

MDA receives commercial contracts for on-orbit servicing technologies

The OSAM-1 mission, formerly known as Restore-L, will demonstrate robotic servicing technologies in orbit, including satellite refueling, assembly and in-space manufacturing. The SPIDER payload's lightweight 16-foot (5-metre) robotic arm will assemble multiple antenna reflector elements to form a single, functional 9-foot (3-metre) communications Ka-band antenna. MDA has announced that it has signed multiple contracts with Maxar Technologies to provide advanced space robotics technologies for the Space Infrastructure Dexterous Robot (SPIDER), a technology demonstration on NASA's On-orbit Servicing, Assembly, and Manufacturing 1 (OSAM-1) mission. MDA will deliver an enabling technology suite of advanced robot control software and interfaces to help achieve assembly and servicing tasks never done to date. These include:

+ A dexterous end effector;
+ Robotic arm control software;
+ Motor control software;
+ Robotic console command and control software and computers;
+ Grapple fixtures and targets for on-orbit assembly interfaces, and
+ Compact cameras and controllers for situational awareness and robotic arm operation.

MDA will also deliver the Motor Control Electronics and Arm Control Electronics on the SPIDER robotic arm. These essential components drive and control each of the motors and joints of the arm as well as providing the data routing and interfacing between joints and cameras.

The work on these three contracts will be performed at MDA facilities in Brampton and Ste-Anne-de-Bellevue. These products will be delivered in mid-to-late 2021 and incorporated into Maxar's robotic system. They will not only support the goal of making on-orbit assembly commercially viable, but could also support other on-orbit services like debris removal, anomaly resolution, life extension, and salvage of stranded spacecraft.

There is a clear need to service the world's space infrastructure, both commercial and government, and MDA is well positioned to address this burgeoning market.

MDA has unparalleled and proven space servicing capabilities developed through various government programs over the last 40 years, including the Canadian government's Canadarm program for the US Space Shuttle and International Space Station programs as well as other on-orbit servicing demonstrations such as the successful DARPA Orbital Express mission and NASA's Robotic Refueling Missions on the space station.

NASA's Curiosity Takes Selfie With 'Mary Anning' on the Red Planet

NASA's Curiosity Mars rover has a new selfie. This latest is from a location named "Mary Anning," after a 19th-century English paleontologist whose discovery of marine-reptile fossils were ignored for generations because of her gender and class. The rover has been at the site since this past July, taking and analyzing drill samples. Made up of 59 pictures stitched together by imaging specialists, the selfie was taken on Oct. 25, 2020 – the 2,922nd Martian day, or sol, of Curiosity's mission. Scientists on the Curiosity team thought it fitting to name the sampling site after Anning because of the area's potential to reveal details about the ancient environment. Curiosity used the rock drill on the end of its robotic arm to take samples from three drill holes called "Mary Anning," "Mary Anning 3," and "Groken," this last one named after cliffs in Scotland's Shetland Islands. The robotic scientist has conducted a set of advanced experiments with those samples to extend the search for organic (or carbon-based) molecules in the ancient rocks. Since touching down in Gale Crater in 2012, Curiosity has been ascending Mount Sharp to search for conditions that might once have supported life. This past year, the rover has explored a region of Mount Sharp called Glen Torridon, which likely held lakes and streams billions of years ago. Scientists suspect this is why a high concentration of clay minerals and organic molecules was discovered there.

This close-up shot shows the three drill holes created by NASA's Curiosity Mars rover at the "Mary Anning" location.

 Credit: NASA/JPL-Caltech/MSSS.

It will take months for the team to interpret the chemistry and minerals in the samples from the Mary Anning site. In the meantime, the scientists and engineers who have been commanding the rover from their homes as a safety precaution during the coronavirus pandemic have directed Curiosity to continue its climb of Mount Sharp. The rover's next target of exploration is a layer of sulfate-laden rock that lies higher up the mountain. The team hopes to reach it in early 2021.

NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, leads the Curiosity mission. Curiosity took the selfie using a camera called the Mars Hand Lens Imager (MAHLI), located on the end of its robotic arm. (Videos explaining how Curiosity's selfies are taken can be found here.) MAHLI was built by Malin Space Science Systems in San Diego.

For more information about Curiosity, visit:

https://mars.nasa.gov/msl/

https://nasa.gov/msl