OrbitalHub

NASA dixit:

“Using NASA’s Hubble and Kepler space telescopes, astronomers have uncovered tantalizing evidence of what could be the first discovery of a moon orbiting a planet outside our solar system. This moon candidate, which is 8,000 light-years from Earth in the Cygnus constellation, orbits a gas-giant planet that, in turn, orbits a star called Kepler-1625. Researchers caution that the moon hypothesis is tentative and must be confirmed by follow-up Hubble observations.

Since moons outside our solar system – known as exomoons – cannot be imaged directly, their presence is inferred when they pass in front of a star, momentarily dimming its light. Such an event is called a transit, and has been used to detect many of the exoplanets cataloged to date. However, exomoons are harder to detect than exoplanets because they are smaller than their companion planet, and so their transit signal is weaker when plotted on a light curve that measures the duration of the planet crossing and the amount of momentary dimming. Exomoons also shift position with each transit because the moon is orbiting the planet.”

Astronomers Find First Evidence of Possible Moon Outside Our Solar System

Evidence for a large exomoon orbiting Kepler-1625b

Evidence for an Exomoon around Kepler-1625b

Video Credit: NASA Goddard

NASA dixit:

“Two days before Hurricane Maria devastated Puerto Rico, the NASA-Japan Global Precipitation Measurement Core Observatory satellite captured a 3-D view of the storm. At the time Maria was a Category 1 hurricane. The 3-D view reveals the processes inside the hurricane that would fuel the storm’s intensification to a category 5 within 24 hours.

For the first time in 360-degrees, this data visualization takes you inside the hurricane. The precipitation satellite has an advanced radar that measures both liquid and frozen water. The brightly colored dots show areas of rainfall, where green and yellow show low rates and red and purple show high rates. At the top of the hurricane, where temperatures are colder, blue and purple dots show light and heavy frozen precipitation. The colored areas below the dots show how much rain is falling at the surface.”

Dive Into a 360-View of Hurricane Maria

Video Credit: NASA Goddard

ESA dixit:

“When a small Solar System body such as a moon or an asteroid passes in front of a star and temporarily blocks its light, the occultation is an extraordinary chance for astronomers to study the properties of the foreground object. And, of course, the more accurate the prediction of both objects’ positions on the sky, the better the observations. This is why, when a group of astronomers were planning to observe the rare occultation of a distant star by Neptune’s moon Triton on 5 October 2017, they made a special request to the Gaia team.

The astronomers, led by Bruno Sicardy from Pierre and Marie Curie University and the Observatory of Paris, France, had used all available observations to compute the path that the moon’s shadow would sweep across our planet. Within less than three minutes, the occultation would first cross Europe and North Africa, rapidly moving towards North America. They knew that somewhere, within this couple of thousand kilometre-wide stretch, would lie a very special thin strip, only about 100-km across. Observers situated on this strip would be perfectly aligned with both Triton and the distant star, and therefore able to see the so-called central flash. This sharp brightening of the star happens half way through the occultation, and is caused by focussing of the starlight by deep layers in the moon’s atmosphere – about 10 km above surface. The central flash contains all-important information to study the profile of Triton’s atmosphere and the possible presence of haze in it.”

Chasing a Stellar Flash with Assistance from Gaia

Catching the Shadow of a Neptunian Moon

Video Credit: ESA

NASA dixit:

“Global sea level rise is accelerating incrementally over time rather than increasing at a steady rate, as previously thought, according to a new study based on 25 years of NASA and European satellite data. If the rate of ocean rise continues to change at this pace, sea level will rise 26 inches (65 centimeters) by 2100, enough to cause significant problems for coastal cities.”

Video Credit: NASA

ESA dixit:

“A safe and secure space environment is a requirement for all current and future space activities. Analyses performed by ESA and NASA indicate that the only means of sustaining the orbital environment at a safe level for space operations in future will be by carrying out both active debris removal and end-of-life de-orbiting or re-orbiting of future space assets. ESA, through its Clean Space (CS) initiative, is devoting an increasing amount of attention to the environmental impact of its activities.

To contribute to space sustainability, some agencies and governments have established or adopted policies to mitigate space debris creation. For instance, the ESA Policy on Space Debris states that satellites must remove themselves from the protected regions, less than 25 years for LEO and less than two months for GEO after operations are complete.

Nevertheless, even if spacecraft are designed to achieve an End-of-Life (EOL) compliance with these Space Debris Mitigation (SDM) requirements, a failure of the spacecraft, or other unforeseen events, may lead to the satellite becoming non-operational in the protected regions (this is even reflected in the SDM requirement, which calls for a reliability of 90%). Therefore, such a failed satellite may require active debris removal (ADR).”

Video Credit: ESA

Wikipedia dixit:

“With the 1979 beginning of the NASA Orbital Debris Program the term space debris also includes the debris from the mass of defunct, artificially created objects in space, most notably in Earth orbit, such as old satellites and spent rocket stages. It includes the fragments from their disintegration, erosion and collisions. As of December 2016, five satellite collisions have resulted in generating space waste. Space debris is also known as orbital debris, space junk, space waste, space trash, space litter or space garbage.

As of 5 July 2016, the United States Strategic Command tracked a total of 17,852 artificial objects in orbit above the Earth, including 1,419 operational satellites. However, these are just objects large enough to be tracked. As of July 2013, more than 170 million debris smaller than 1 cm (0.4 in), about 670,000 debris 1–10 cm, and around 29,000 larger debris were estimated to be in orbit. Collisions with debris have become a hazard to spacecraft; they cause damage akin to sandblasting, especially to solar panels and optics like telescopes or star trackers that cannot be covered with a ballistic Whipple shield (unless it is transparent).

Below 2,000 km (1,200 mi) Earth-altitude, debris are denser than meteoroids; most are dust from solid rocket motors, surface erosion debris like paint flakes, and frozen coolant from RORSAT nuclear-powered satellites. For comparison, the International Space Station orbits in the 300–400 kilometres (190–250 mi) range, and the 2009 satellite collision and 2007 antisat test occurred at 800 to 900 kilometres (500 to 560 mi) altitude. The ISS has Whipple shielding; however, known debris with a collision chance over 1/10,000 are avoided by maneuvering the station.

The Kessler syndrome, a runaway chain reaction of collisions exponentially increasing the amount of debris, has been hypothesized to ensue beyond a critical density. This could affect useful polar-orbiting bands, increases the cost of protection for spacecraft missions and could destroy live satellites. Whether Kessler syndrome is already underway has been debated. The measurement, mitigation, and potential removal of debris are conducted by some participants in the space industry.”

Video Credit: ESA