Supersonic Parachute

I am always amazed at parachute tests,.  A capsule (see link below) is speeding along at 12 times the speed of sound and then the parachute is deployed creating incredible stresses on the system, in the end designs it all holds together. For some unknown reason this test got me to wondering how much stretch the attaching parachute cord occurs and what the tensile strength is, for that matter what it is made of.   Oh I’m sure the data is out there, I just need to find it.

About the test:
ESA — This parachute deployed at supersonic velocity from a test capsule hurtling down towards snow-covered northern Sweden from 679 km up, proving a crucial technology for future spacecraft landing systems.

Planetary landers or reentering spacecraft need to lose their speed rapidly to achieve safe landings, which is where parachutes come in. They have played a crucial role in the success of ESA missions such as ESA’s Atmospheric Entry Demonstrator, the Huygens lander on Saturn’s moon Titan and the Intermediate Experimental Vehicle spaceplane.

This 1.25-m diameter ‘Supersonic Parachute Experiment Ride on Maxus’, or Supermax, flew piggyback on ESA’s Maxus-9 sounding rocket on 7 April, detaching from the launcher after its solid-propellant motor burnt out.

After reaching its maximum 679 km altitude, the capsule began falling back under the pull of gravity. It fell at 12 times the speed of sound, undergoing intense aerodynamic heating, before air drag decelerated it to Mach 2 at an altitude of 19 km.

At this point the capsule’s parachute was deployed to stabilise it for a soft landing, and allowing its onboard instrumentation and camera footage to be recovered intact.

The experiment was undertaken by UK companies Vorticity Ltd and Fluid Gravity Engineering Ltd under ESA contract.

The data gathered by this test are being added to existing wind tunnel test campaigns of supersonic parachutes to validate newly developed software called the Parachute Engineering Tool (also developed by Vorticity), allowing mission designers to accurately assess the use of parachutes.

LISA Mission Ends

The Laser Interferometer Space Antenna or LISA mission ended yesterday.

The LISA Pathfinder mission set out to test the technology needed to detect gravity waves.  The gravity waves were predicted to exist by Einstein a hundred years ago (actually in 1916).  Could they be found?

Thanks to the LISA mission we know, yes they can!  Here’s a new video from ESA that gives a good overview.

Enceladus Jets

 

We are just two months from the end of the Cassini mission!

NASA – Enceladus’ intriguing south-polar jets are viewed from afar, backlit by sunlight while the moon itself glows softly in reflected Saturn-shine.

Observations of the jets taken from various viewing geometries provide different insights into these remarkable features. Cassini has gathered a wealth of information in the hopes of unraveling the mysteries of the subsurface ocean that lurks beneath the moon’s icy crust.

This view looks toward the Saturn-facing hemisphere of Enceladus (313 miles or 504 kilometers across). North is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 13, 2017.

The view was acquired at a distance of approximately 502,000 miles (808,000 kilometers) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 176 degrees. Image scale is 3 miles (5 kilometers) per pixel.

Image Credit: NASA/JPL-Caltech/Space Science Institute

Curiosity’s Traction Control

Readers who’ve been around for a while know we’ve been keeping an eye on Curiosity’s wheels; they have taken a beating traveling around on Mars.

NASA of course has been working the problem right from the beginning and they now have come up with an algorithm to help with the problem.

JPL/NASA (Andrew Good) – There are no mechanics on Mars, so the next best thing for NASA’s Curiosity rover is careful driving.

A new algorithm is helping the rover do just that. The software, referred to as traction control, adjusts the speed of Curiosity’s wheels depending on the rocks it’s climbing. After 18 months of testing at NASA’s Jet Propulsion Laboratory in Pasadena, California, the software was uploaded to the rover on Mars in March. Mars Science Laboratory’s mission management approved it for use on June 8, after extensive testing at JPL and multiple tests on Mars.

Even before 2013, when the wheels began to show signs of wear, JPL engineers had been studying how to reduce the effects of the rugged Martian surface. On level ground, all of the rover’s wheels turn at the same speed. But when a wheel goes over uneven terrain, the incline causes the wheels behind or in front of it to start slipping.

This change in traction is especially problematic when going over pointed, embedded rocks. When this happens, the wheels in front pull the trailing wheels into rocks; the wheels behind push the leading wheels into rocks.

In either case, the climbing wheel can end up experiencing higher forces, leading to cracks and punctures. The treads on each of Curiosity’s six wheels, called grousers, are designed for climbing rocks. But the spaces between them are more at risk.

“If it’s a pointed rock, it’s more likely to penetrate the skin between the wheel grousers,” said Art Rankin of JPL, the test team lead for the traction control software. “The wheel wear has been cause for concern, and although we estimate they have years of life still in them, we do want to reduce that wear whenever possible to extend the life of the wheels.”

The traction control algorithm uses real-time data to adjust each wheel’s speed, reducing pressure from the rocks. The software measures changes to the suspension system to figure out the contact points of each wheel. Then, it calculates the correct speed to avoid slippage, improving the rover’s traction.

During testing at JPL, the wheels were driven over a six-inch (15-centimeter) force torque sensor on flat terrain. Leading wheels experienced a 20 percent load reduction, while middle wheels experienced an 11 percent load reduction, Rankin said.

Traction control also addresses the problem of wheelies. Occasionally, a climbing wheel will keep rising, lifting off the actual surface of a rock until it’s free-spinning. That increases the forces on the wheels that are still in contact with terrain. When the algorithm detects a wheelie, it adjusts the speeds of the other wheels until the rising wheel is back into contact with the ground.

Rankin said that the traction control software is currently on by default, but can be turned off when needed, such as for regularly scheduled wheel imaging, when the team assesses wheel wear.

The software was developed at JPL by Jeff Biesiadecki and Olivier Toupet. JPL, a division of Caltech in Pasadena, manages the Curiosity mission for NASA.

Image: NASA

Fly Overs

There are two, first New Horizons over Pluto:

And second, a flyover of Charon:

NASA (via YouTube) – Using actual New Horizons data and digital elevation models of Pluto and its largest moon Charon, mission scientists have created flyover movies that offer spectacular new perspectives of the many unusual features that were discovered and which have reshaped our views of the Pluto system – from a vantage point even closer than the spacecraft itself.

How To Get Observing Time

Observing time on the world-class observatories is limited and highly sought after by researchers.  It is not an easy undertaking, here’s a video about it’s done from the ESO.

The Great Red Spot!

Hey look at this! Yesterday I said the Juno images would be available on 14 July, well NASA came through early!

This is my rendition of Jupiter’s Great Red Spot. You know, I do have Photoshop on another computer that is currently in storage. I should get it out and fire it up. In the mean time, I did this from the original located at JunoCam (it is the TAN SEASHORE link).

Click here for my version, of the complete image.

and

Click here for the original if you have trouble at the JunoCam site, which is doubtful.  Download it and see what you can do.

A Large Sunspot

AND a Juno update.  First take a look at this sunspot.  The spot is named AR2665 and it is huge.  Estimates are about 120,000 km / 74,560 miles from end to end and its a configuration that is not all that stable.  If this thing were to let off a flare, it could be an M-class and would be directed straight at us likely to produce vivid auroras at the least.

The image comes from the Solar Dynamics Observatory using the onboard Helioseismic and Magnetic Imager (HMI) is one of three instruments aboard the Solar Dynamics Observatory(SDO) designed to study oscillations and the magnetic field at the solar surface. HMI observes the full solar disk at 6173 Å with a resolution of 1 arc second.

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The Juno spacecraft successfully flew over the Great Red Spot of Jupiter at a distance of only 9,000 km / 5,600 miles. Images to be released on 14 July.

Image: NASA / SDO