Wednesday, July 31, 2019

LightSail 2's Mission Has Achieved Its Main Objective!

An image that was taken of LightSail 2's solar sail during its successful deployment process on July 23, 2019.
The Planetary Society

LightSail 2 Spacecraft Successfully Demonstrates Flight by Light (Press Release)

Pasadena, CA — Years of computer simulations. Countless ground tests. They've all led up to now. The Planetary Society's crowdfunded LightSail 2 spacecraft is successfully raising its orbit solely on the power of sunlight.

Since unfurling the spacecraft's silver solar sail last week, mission managers have been optimizing the way the spacecraft orients itself during solar sailing. After a few tweaks, LightSail 2 began raising its orbit around the Earth. In the past 4 days, the spacecraft has raised its orbital high point, or apogee, by about 2 kilometers. The perigee, or low point of its orbit, has dropped by a similar amount, which is consistent with pre-flight expectations for the effects of atmospheric drag on the spacecraft. The mission team has confirmed the apogee increase can only be attributed to solar sailing, meaning LightSail 2 has successfully completed its primary goal of demonstrating flight by light for CubeSats.

"We're thrilled to announce mission success for LightSail 2," said LightSail program manager and Planetary Society chief scientist Bruce Betts. "Our criteria was to demonstrate controlled solar sailing in a CubeSat by changing the spacecraft’s orbit using only the light pressure of the Sun, something that’s never been done before. I'm enormously proud of this team. It's been a long road and we did it."

The milestone makes LightSail 2 the first spacecraft to use solar sailing for propulsion in Earth orbit, the first small spacecraft to demonstrate solar sailing, and just the second-ever solar sail spacecraft to successfully fly, following Japan's IKAROS, which launched in 2010. LightSail 2 is also the first crowdfunded spacecraft to successfully demonstrate a new form of propulsion.

"For The Planetary Society, this moment has been decades in the making," said Planetary Society CEO Bill Nye. "Carl Sagan talked about solar sailing when I was in his class in 1977. But the idea goes back at least to 1607, when Johannes Kepler noticed that comet tails must be created by energy from the Sun. The LightSail 2 mission is a game-changer for spaceflight and advancing space exploration."

On Monday, LightSail 2 sent home a new full-resolution image captured by its camera during solar sail deployment. The perspective is opposite to last week’s full-resolution image and shows the sail more fully deployed. LightSail 2's aluminized Mylar sail shines against the blackness of space, with the Sun peeking through near a sail boom.

The mission team will continue raising LightSail 2's orbit for roughly a month, until the perigee decreases to the point where atmospheric drag overcomes the thrust from solar sailing. During the orbit-raising period, the team will continue optimizing the performance of the solar sail.

"We've been working since sail deployment to refine the way the spacecraft tracks the Sun," said LightSail 2 project manager Dave Spencer. "The team has done a great job getting us to the point where we can declare mission success. Moving ahead, we're going to continue working to tune the sail control performance and see how much we can raise apogee over time."

One such refinement involves LightSail 2's single momentum wheel, which rotates the spacecraft broadside and then edge-on to the Sun each orbit to turn the thrust from solar sailing on and off. Momentum wheels can “saturate,” hitting predefined speed limits, after which they are no longer effective at rotating the spacecraft. Most spacecraft use chemical thrusters to desaturate momentum wheels; LightSail 2 relies on electromagnetic torque rods, which orient the spacecraft by pushing against Earth's magnetic field.

LightSail 2’s momentum wheel currently reaches its saturation limit a couple of times per day, and desaturating the wheel temporarily takes the spacecraft out of its proper orientation for solar sailing. The mission team already applied a software update that increased the time between saturation events, and is also working to automate the desaturation process. Both refinements should result in improved solar sailing performance.

After LightSail 2's month-long orbit raising phase, the spacecraft will begin to deorbit, eventually reentering the atmosphere in roughly a year. The aluminized Mylar sail, about the size of a boxing ring, may currently be visible for some observers at dusk and dawn. The Planetary Society's mission control dashboard shows upcoming passes based on user location, and includes a link to a page that highlights passes when the sail is more likely to be visible.

Roughly 50,000 Planetary Society members and private citizens from more than 100 countries, as well as foundations and corporate partners, donated to the LightSail 2 mission, which cost $7 million from 2009 through March 2019.

"LightSail 2 proves the power of public support," said Planetary Society COO Jennifer Vaughn. "This moment could mark a paradigm shift that opens up space exploration to more players. It amazes me that 50,000 people came together to fly a solar sail. Imagine if that number became 500,000 or 5 million. It’s a thrilling concept."

The Planetary Society shares LightSail program data with other organizations so that solar sail technology can be applied to future space exploration missions. The Society presented initial LightSail 2 results this week at the 5th International Symposium on Solar Sailing in Aachen, Germany. Results are also being shared with NASA's NEA Scout mission, which is launching a solar sail-powered CubeSat to visit a near-Earth asteroid as early as next year.

LightSail 2 is one of several Planetary Society science and technology projects that aim to advance space science and exploration. Earlier this month, NASA chose PlanetVac, a Society-funded technology built by Honeybee Robotics that simplifies the process of collecting samples from other worlds, to fly to the Moon as part of the agency's Commercial Lunar Payload Services (CLPS) program.

The LightSail program began in 2009 under the direction of Planetary Society co-founder Louis Friedman, following the launch of Cosmos 1, the world's first solar sail that did not reach orbit. Friedman and Society co-founders Carl Sagan and Bruce Murray championed the idea of solar sailing more than 4 decades ago with a proposed solar sail mission to Halley's Comet.

Source: The Planetary Society

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A chart showing the change in orbital altitude for LightSail 2 after it successfully deployed its solar sail on July 23, 2019.
The Planetary Society

Wednesday, July 24, 2019

LightSail 2 Has Spread Its Wings in Orbit!

An image that was taken of LightSail 2's solar sail after it was successfully deployed on July 23, 2019.
The Planetary Society

LightSail 2 Successfully Deploys Solar Sail (Press Release)

The Planetary Society’s LightSail 2 spacecraft has successfully deployed the large, aluminized Mylar sail it will use to raise its orbit solely with sunlight.

Flight controllers at Cal Poly San Luis Obispo in California commanded the spacecraft to deploy its solar sails yesterday at about 11:47 PDT (18:47 UTC). Images captured during the deployment sequence and downloaded today show the 32-square-meter sail, which is about the size of a boxing ring, deploying as the spacecraft flew south of the continental United States.

Sail deployment marks a major milestone for the LightSail 2 mission, which aims to demonstrate solar sailing as a viable method of propulsion for CubeSats—small, standardized satellites that have lowered the cost of space exploration.

“Yesterday, we successfully set sail on beams of sunlight,” said Bill Nye, CEO of The Planetary Society. “Thanks to our team and our tens of thousands of supporters around the world, the dream started by The Planetary Society’s founders more than 4 decades ago has taken flight.”

Bruce Betts, Planetary Society chief scientist and LightSail program manager, added, “We’re ecstatic! The mission team has worked for years to get to this moment when we can start solar sailing.”

Following the start of sail deployment on 23 July, telemetry from LightSail 2 showed the spacecraft’s small motor was rotating properly, extending four, 4-meter cobalt-alloy booms from their central spindle. The booms unwind like carpenter’s tape measures and are attached to 4 triangular sail sections that together form the square solar sail.

Though the motor activity itself was a good indicator of success, confirmation that the sails deployed successfully was only possible via imagery from LightSail 2’s dual cameras. The cameras have 185-degree fields of view, and together can image the entire sail from the main LightSail bus, which is about the size of a loaf of bread.

“The successful deployment of the solar sail and the onset of sail control completes our critical post-launch phase,” said LightSail 2 project manager David Spencer. “Now we are prepared for the solar sail's mission, to track how the orbit changes and evaluate solar sailing performance.”

The deployment milestone comes 4 weeks after LightSail 2 launched from Kennedy Space Center, Florida aboard a SpaceX Falcon Heavy rocket, and 3 weeks after the Georgia Tech student-built Prox-1 spacecraft deployed LightSail 2 into orbit. The mission team spent a week checking out the spacecraft’s systems before rescheduling sail deployment to allow extra time for testing and tuning the attitude control system.

Preliminary data shows LightSail 2 is already turning its solar sail broadside to the Sun once per orbit, giving the spacecraft a gentle push no stronger than the weight of a paperclip. Solar photons have no mass, but they have momentum, and as they reflect off the solar sail, some of that momentum is transferred and creates thrust. While this thrust is slight, it is continuous and over time will raise LightSail 2’s orbit.

The orbit-raising portion of the mission will last about 1 month. LightSail 2 does not have the capability to circularize its orbit—as one side of the spacecraft’s orbit raises due to solar sailing, the other side will dip lower into Earth’s atmosphere, until atmospheric drag overcomes the slight force from solar sailing. LightSail 2 is expected to reenter the atmosphere in roughly 1 year.

Source: The Planetary Society

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A mini-DVD bearing the names of over 23,300 Kickstarter backers (including me) is visible on the LightSail 2 spacecraft...near the left side of this image.
The Planetary Society

My certificate for supporting the LightSail 2 mission through Kickstarter.

Wednesday, July 17, 2019

Only 365 Days Till America's Next Robotic Rover Heads to the Red Planet...

Engineers install the sensor turret to the Mars 2020 rover's robotic arm at NASA's Jet Propulsion Laboratory near Pasadena, California...on July 11, 2019.
NASA / JPL - Caltech

Mars 2020 Rover: T-Minus One Year and Counting (News Release)

The launch period for NASA's Mars 2020 rover opens exactly one year from today, July 17, 2020, and extends through Aug. 5, 2020. The mission will launch from Cape Canaveral Air Force Station in Florida and land at Mars' Jezero Crater on Feb. 18, 2021.

"Back when we started this project in 2013, we came up with a timeline to chart mission progress," said John McNamee, Mars 2020 project manager at NASA's Jet Propulsion Laboratory near Pasadena, California. "That every single major spacecraft component on a project with this level of innovation is synching right now with that timeline is a testament to the innovation and perseverance of a great team."

In this image, taken on July 11, 2019, engineers at JPL install a sensor-filled turret on the end of the rover's 7-foot-long (2.1-meter-long) robotic arm. The rover's turret includes HD cameras, the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC) science instrument, the Planetary Instrument for X-ray Lithochemistry (PIXL), and a percussive drill and coring mechanism.

On Mars, the arm and turret will work together, allowing the rover to work as a human geologist would: by reaching out to interesting geologic features, scraping, analyzing and even collecting them for further study via Mars 2020's Sample Caching System, which includes 17 motors and will collect samples of Martian rock and soil that will be returned to Earth by a future mission.

JPL is building and will manage operations of the Mars 2020 rover for the NASA Science Mission Directorate at the agency's headquarters in Washington. NASA will use Mars 2020 and other missions, including to the Moon, to prepare for human exploration of the Red Planet. The agency intends to establish a sustained human presence on and around the Moon by 2028 through NASA's Artemis lunar exploration plans.

If you want to send your name to Mars with NASA's 2020 mission, you can do so until Sept. 30, 2019. Add your name to the list and obtain a souvenir boarding pass to Mars here:

https://go.nasa.gov/Mars2020Pass

Source: Jet Propulsion Laboratory

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An artist's concept of NASA's Mars 2020 rover studying the surface of the Red Planet.
NASA / JPL - Caltech

Thursday, July 11, 2019

Hayabusa2 Has Collected More Samples from the Surface of Asteroid Ryugu!

A snapshot of Hayabusa2's sampler horn making contact with the surface of asteroid Ryugu...as seen from the spacecraft's small monitor camera on July 11, 2019.
JAXA

Success of the Second Touchdown of Asteroid Explorer Hayabusa 2 (Press Release)

The Japan Aerospace Exploration Agency (JAXA) performed a series of operations for the second touchdown of Asteroid Explorer Hayabusa2 on the Ryugu asteroid and the collection of its soil samples.

From the data sent from Hayabusa2, it has been confirmed that the touchdown sequence, including the discharge of a projectile for sampling, was completed successfully. Hayabusa2 is functioning normally, and thus the second touchdown ended with success.

Source: Japan Aerospace Exploration Agency

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Saturday, July 06, 2019

The Brow Has Officially Joined the Lake Show! (PS: Screw You, Kawhi...)

Anthony Davis officially became a Los Angeles Laker on July 6, 2019.

Lakers Acquire Anthony Davis (Press Release)

The Los Angeles Lakers have acquired forward Anthony Davis from the New Orleans Pelicans in exchange for Lonzo Ball, Josh Hart, Brandon Ingram, the draft rights to De'Andre Hunter, two first round picks, a first-round pick swap right and cash. As part of the trade, the Lakers also sent Isaac Bonga, Jemerrio Jones, Moritz Wagner and a future second round draft pick to the Wizards, who in return, sent cash consideration to the Pelicans.

"Anthony Davis is arguably the most dominant all-around young player in today's NBA," said Lakers general manager Rob Pelinka. "Anthony represents everything we stand for, with his unwavering commitment to excellence as both a person and athlete. This is a historic moment for the Lakers franchise, and we couldn't be more proud to have him."

A three-time All-NBA First Team honoree (2015, ‘17, ‘18), six-time NBA All-Star and one-time Olympic Gold Medalist for Team USA (2012), Davis has averaged 23.7 points (.517 FG%), 10.5 rebounds, 2.4 blocks, 2.1 assists and 1.4 steals over his seven-year career in the NBA.

Last season, Davis played and started in 56 games for New Orleans, averaging 25.9 points (.517 FG%), 12.0 rebounds, 3.9 assists, 2.4 blocks and 1.6 steals in 33.0 minutes. A three-time league-leader in blocks, Davis was named to the NBA’s All-Defensive First Team in 2018, while earning Second Team honors in 2015 and 2017. Additionally, he has been voted Western Conference Player of the Month twice, coming in back-to-back months in February and March of 2018, and has earned the league’s Player of the Week award on five occasions. In 2017, he was named Most Valuable Player of the NBA All-Star Game after scoring a record 52 points in the game.

Originally from Chicago, IL, Davis was selected first overall in the 2012 NBA Draft and went on to earn First Team All-Rookie honors after totaling 20 double-doubles with averages of 13.5 points, 8.2 rebounds, 1.8 blocks, 1.2 steals and 1.0 assist per game.

In his lone season at Kentucky, Davis was voted as the consensus National Player of the Year and a First Team All-American after leading the Wildcats to the 2012 NCAA Championship. The NABC and SEC Defensive Player of the Year was also SEC Player of the Year, tallying 14.2 points (.623 FG%), 10.4 rebounds, 4.7 blocks, 1.4 steals and 1.3 assists in 40 games.

Source: Lakers.com

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The 2019-'20 team roster for the Los Angeles Lakers.