Carnival of Space #465
After a protracted silence, the Carnival of Space returns, with this installment officially numbered 465. It’s a bumper crop this week, with more submissions than we’ve seen in a long time so let’s cut the frills and dive straight in to the content:
- From Planetaria, Mars rovers update: Curiosity turns toward Mount Sharp, Opportunity finishes in Marathon Valley
- From The Venus Transit, To celebrate Juno arrival to Jupiter here are some interesting facts about this planet
- From the official blog of the Chandra X-ray Telescope, Tracking Down a Stealthy Black Hole
- Also from Chandra, How to hold a dead star in your hand
- From Universe Today, New System Discovered with Five Planets
- And also from Universe Today, Jupiter’s Magnetosphere Will Blow Your Mind While it Kills Your Spacecraft
- From Next Big Future, “A team of astronomers say that the next search for advanced extraterrestrial civilizations should look for stars – or even galaxies – that have vanished without a trace, as anything so unexplainable could only be due to life far more intelligent than us.Beatriz Villarroel at Uppsala University in Sweden says this crazy idea has been gnawing at her since her first year of graduate studies. Now she and two undergraduates have finally taken the plunge. They scoured multiple surveys of the night’s sky by eye in order to see if any of nearly 300,000 light sources disappeared from one survey to the next.So far the results are mixed. The team found one interesting artefact that looks like it might have vanished, but they can’t be sure. “It was a depressing case in the sense that we neither could reject it and neither could we say that it was a real candidate,” says Villarroel. Although the team checked for so-called false positives, throwing out hundreds of similar disappearing objects, this one withstood all tests – but only just.”
- Also from Next Big Future, “At about 12:15 pm PDT today (3:15 p.m. EDT), mission controllers will transmit command product “ji4040” into deep space, to transition the solar-powered Juno spacecraft into autopilot. It will take nearly 48 minutes for the signal to cover the 534-million-mile (860-million-kilometer) distance between the Deep Space Network Antenna in Goldstone, California, to the Juno spacecraft. While sequence ji4040 is only one of four command products sent up to the spacecraft that day, it holds a special place in the hearts of the Juno mission team.“Ji4040 contains the command that starts the Jupiter Orbit insertion sequence,” said Ed Hirst, mission manager of Juno from NASA’s Jet Propulsion Laboratory in Pasadena, California. “As soon as it initiates — which should be in less than a second — Juno will send us data that the command sequence has started.” NASA’s Juno spacecraft will arrive at Jupiter in July, 2016 to study our solar system’s largest planet. From a unique polar orbit, Juno will repeatedly dive between the planet and its intense belts of charged particle radiation, coming only about 3,000 miles (5,000 kilometers) from the cloud tops at closest approach. Juno’s primary goal is to improve our understanding of Jupiter’s formation and evolution. The spacecraft will investigate the planet’s origins, interior structure, deep atmosphere and magnetosphere. Juno’s study of Jupiter will help us to understand the history of our own solar system and provide new insight into how planetary systems form and develop in our galaxy and beyond”
- And again, from Next Big Future, History and Future of Laser Pushed Sails which have a clear technology roadmap and $100 million in funding. Photon propulsion is an old idea going back many years, with some poetic references several hundred years ago. A decade ago what they now propose would have been pure fantasy. It is no longer fantasy. Recent dramatic and poorly-appreciated technological advancements in directed energy have made what we propose possible, though difficult. There has been a game change in directed energy technology whose consequences are profound for many applications including photon driven propulsion. This allows for a completely modular and scalable technology with radical consequences. For photon engines (emission – no reflection) ISP = 30,000,000 while for the reflection case it is twice that or 60,000,000. In the idealized case of laser driven ablation engine we get the thrust ratio, compared to the photon reflection case, of c/ vrel ~ 15000 to 30000 consistent with our detailed ablation simulations. It is also possible to use laser heated H2 via heat exchangers to get even high ISP, due largely to the lower molecular mass, and thus higher exhaust speed for a given temperature
- And finally, bringing us home, one final piece from Next Big Future: “Spacecoach concept is to use urine and gas as propellent for electric engine propulsion for long duration space missions to reduce mass by 20 times. On an 800 day space mission, astronauts would need 24 tons for six people for consumables (water, oxygen and food). McConnell and Alex Tolley have an idea is to deploy electric engines that use reclaimed water and waste gases to do the job. Spacecoach enables us to begin building a space infrastructure that can extend past Mars to include the main asteroid belt. Using electric propulsion driven by a solar photovoltaic array, it achieves higher exhaust velocity than chemical rockets by a factor or ten, pulling much greater delta v from the same amount of propellant. Use water as propellant and you reduce the mass of the system by what McConnell estimates to be a factor of between 10 and 20.The ships are propelled mostly by electric propulsion technology, and use water, carbon dioxide and gasified waste as propellant, essentially they convert the crew waste streams and reclaimed water into propellant after first pass use by the crew. Water and water rich material is used for other purposes, such as radiation shielding and heat management, while in passive storage. Habitable areas are derived from inflatable structures, such as Bigelow Aerospace units, to allow large structures to be fit into existing launch systems and then be self-assembled in space with less manual intervention. The ships are interplanetary vessels that never enter an atmosphere. They’re also completely reusable, allowing costs to be amortized, and their habitable areas are large inflatable structures that can be assembled in space. Thus we travel within a modular spacecraft using external landers and whatever other modules are required by the mission at hand. They will also be able to fly many missions, with a useful life comparable to the ISS (20+ years) so their construction and initial launch cost can be amortized across 5 to 10 missions. Everything about the design is for reusability and multiple uses.