To see distant stars and planets, astronomers must first calibrate their equipment to compensate for Earth’s blurry atmosphere — and that’s a whole lot easier said than done. In fact, to pull it off, they have to actually create artificial stars, dubbed ‘guide stars’, using really, really big lasers.
Now, researchers from the European Southern Observatory’s (ESO) Paranal Observatory in Chile have created the most powerful one to date — a system they call the Four Laser Guide Star Facility (4LGSF).
The new system, which has been tested since last September, works by shooting four 29.9-centimetre (11.8-inch), 22-watt beams into the atmosphere to basically mark the sky.
Parachutes are plaguing space programs. SpaceX doesn’t like Parachutes. They are difficult to design, hard to package, and easy to damage. The larger the mass of the spacecraft, the more effort to slow down. Larger, more efficient, complex parachute systems are needed. Several failures have hit the industry over the last few years, including SpaceX Crew Dragon, ESA ExoMars, Boeing CST-100, and the NASA Orion to name a few.
How do parachutes work and why are they hard?
The idea of a parachute is simple. All falling objects fall the same when under the same conditions… that is so long as no outside force is exerted on it. So two objects dropped from the same altitude, one a feather and hammer will fall equally. Don’t believe me? NASA tested it on the Moon. During Apollo 15 moon walk, Commander David Scott performed a live demonstration for the television cameras. Commander Scott did the Apollo 15 Hammer and Feather test. He held out a geologic hammer and a Falcon feather and dropped them at the same time. Because there is not an atmosphere on the Moon, they were essentially in a vacuum. With no air resistance force, the feather fell at the same rate as the hammer. Ironically, Apollo 15 had a second demonstration of falling objects when one of the parachutes failed to function as planned.
On Earth, and any other planet with an atmosphere, air acts as a resistance force for an object moving through it. We can get more air resistance force by increasing the surface area. Depending on the shape of the object, it’s orientation, and the amount of resistance will increase, and therefore slow the object down. Unbalanced and uncorrected resistance can cause the object to start to turn, twist and tumble. A parachute system is deployed to generate air resistance from the atmosphere. (note that the thicker the atmosphere the more resistance) Parachutes designed for use on Earth will not be the same as a parachute designed for Mars.
Part 2 of the Life in Space with COVID19 we will delve into Crew demo-2 where NASA and SpaceX are planning a launch within two months. There are a lot of pre-launch milestones and activities to cover to ensure a safe flight for the Astronauts. If anything goes wrong, there are lives at stake. Now NASA and SpaceX have to contend with another potential setback, COVID19 pandemic. (Click here for part I)
The SpaceX Crew Dragon spacecraft for Demo-2 arrived at the launch site on Feb. 13, 2020. Photo credit: SpaceX
In Part I of why COVID19 pandemic is bad timing for the Space industry, we covered that issues happen because the relationship between complexity, risk, schedule and cost for space missions was not balanced.
One reason we look so often at sail technologies in these pages is that they offer us ways of leaving the propellant behind. But even as we enter the early days of solar sail experimentation in space, we look toward ways of improving them by somehow getting around their need for solar photons. Robert Zubrin’s work with Dana Andrews has helped us see how so-called magnetic sails (magsails) could be used to decelerate a craft as it moved into a destination system. Now Zubrin looks at moving beyond both this and solar wind-deflecting electric sails toward an ingenious propellantless solution. Zubrin presented the work at last April’s Breakthrough Discuss meeting, and today he fills us in on its principles and advantages. Read on for a look at a form of enhanced electric sail the author has christened the Dipole Drive.