All posts by Tom

Through The Gap

Here is one of the images returned from Cassini, it is a raw image with no processing.

This is some welcome news!

NASA – NASA’s Cassini spacecraft is back in contact with Earth after its successful first-ever dive through the narrow gap between the planet Saturn and its rings on April 26, 2017. The spacecraft is in the process of beaming back science and engineering data collected during its passage, via NASA’s Deep Space Network Goldstone Complex in California’s Mojave Desert. The DSN acquired Cassini’s signal at 11:56 p.m. PDT on April 26, 2017 (2:56 a.m. EDT on April 27) and data began flowing at 12:01 a.m. PDT (3:01 a.m. EDT) on April 27.

“In the grandest tradition of exploration, NASA’s Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare,” said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington.

As it dove through the gap, Cassini came within about 1,900 miles (3,000 kilometers) of Saturn’s cloud tops (where the air pressure is 1 bar — comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles (300 kilometers) of the innermost visible edge of the rings.

While mission managers were confident Cassini would pass through the gap successfully, they took extra precautions with this first dive, as the region had never been explored.

“No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn’s other rings, of what we thought this gap between the rings and Saturn would be like,” said Cassini Project Manager Earl Maize of NASA’s Jet Propulsion Laboratory in Pasadena, California. “I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape.”

The gap between the rings and the top of Saturn’s atmosphere is about 1,500 miles (2,000 kilometers) wide. The best models for the region suggested that if there were ring particles in the area where Cassini crossed the ring plane, they would be tiny, on the scale of smoke particles. The spacecraft zipped through this region at speeds of about 77,000 mph (124,000 kph) relative to the planet, so small particles hitting a sensitive area could potentially have disabled the spacecraft.

As a protective measure, the spacecraft used its large, dish-shaped high-gain antenna (13 feet or 4 meters across) as a shield, orienting it in the direction of oncoming ring particles. This meant that the spacecraft was out of contact with Earth during the ring-plane crossing, which took place at 2 a.m. PDT (5 a.m. EDT) on April 26. Cassini was programmed to collect science data while close to the planet and turn toward Earth to make contact about 20 hours after the crossing.

Cassini’s next dive through the gap is scheduled for May 2.

Image and caption: NASA/JPL-Caltech/Space Science Institute

Cassini’s First Dive

Cassini is making its first dive inside the gap between Saturn and the ring system. What will happen? We don’t really know for sure but we are going to find out. I will be checking shortly after 08:00 UT / 0400 ET to see what happened and if all goes really well we might even have some images.

GOOD LUCK CASSINI!!!

Here’s the time line and kind of what is expected from NASA:
NASA’s Cassini spacecraft is set to make its first dive through the narrow gap between Saturn and its rings on April 26, 2017. Because that gap is a region no spacecraft has ever explored, Cassini will use its dish-shaped high-gain antenna (13 feet or 4 meters across) as a protective shield while passing through the ring plane. No particles larger than smoke particles are expected, but the precautionary measure is being taken on the first dive. The Cassini team will use data collected by one of the spacecraft’s science instruments (the Radio and Plasma Wave Subsystem, or RPWS) to ascertain the size and density of ring particles in the gap in advance of future dives. As a result of its antenna-forward orientation, the spacecraft will be out of contact with Earth during the dive.

Below is a list of milestones expected to occur during the event, if all goes as planned:

— 5 p.m. PDT (8 p.m. EDT) on April 25: Cassini is approaching Saturn over the planet’s northern hemisphere in advance of its first of 22 planned dives through the gap between the planet and its rings.

— 1:34 a.m. PDT (4:34 a.m. EDT) on April 26: As it passes from north to south over Saturn, Cassini begins a 14-minute turn to point its high-gain antenna into the direction of oncoming ring particles. In this orientation, the antenna acts as a protective shield for Cassini’s instruments and engineering systems.

— 2 a.m. PDT (5 a.m. EDT) on April 26: Cassini crosses the ring plane during its dive between the rings and Saturn. The spacecraft’s science instruments are collecting data, but Cassini is not in contact with Earth at this time.

No earlier than around midnight PDT on April 26 (3 a.m. EDT on April 27): Earth has its first opportunity to regain contact with Cassini as the giant, 230-foot (70-meter) Deep Space Network antenna at Goldstone, California, listens for the spacecraft’s radio signal.

— Likely no earlier than 12:30 a.m. PDT (3:30 a.m. EDT) on April 27: Images are scheduled to become available from the spacecraft.

Artistic rendering: Credits: NASA/JPL-Caltech

Balloon Launch!

Readers that have been around here for a while knows I really like research balloon launches, this one is the size of a football stadium!

Balloon launches are very challenging and making the difficult appear easy isn’t as easy as you might think. Kind of funny, because I hear a lot of people doing the opposite, make the easy appear difficult, I used to work with some of them.

NASA:
NASA successfully launched its football-stadium-sized, heavy-lift super pressure balloon (SPB) from Wanaka, New Zealand, at 10:50 a.m. Tuesday, April 25 (6:50 p.m. April 24 in U.S. Eastern Time), on a mission designed to run 100 or more days floating at 110,000 feet (33.5 km) about the globe in the southern hemisphere’s mid-latitude band.

Last Look at Titan

Click the image for a larger view.

From NASA:

NASA’s Cassini spacecraft has had its last close brush with Saturn’s hazy moon Titan and is now beginning its final set of 22 orbits around the ringed planet.

The spacecraft made its 127th and final close approach to Titan on April 21 at 11:08 p.m. PDT (2:08 a.m. EDT on April 22), passing at an altitude of about 608 miles (979 kilometers) above the moon’s surface.

Cassini transmitted its images and other data to Earth following the encounter. Scientists with Cassini’s radar investigation will be looking this week at their final set of new radar images of the hydrocarbon seas and lakes that spread across Titan’s north polar region. The planned imaging coverage includes a region previously seen by Cassini’s imaging cameras, but not by radar. The radar team also plans to use the new data to probe the depths and compositions of some of Titan’s small lakes for the first (and last) time, and look for further evidence of the evolving feature researchers have dubbed the “magic island.”

“Cassini’s up-close exploration of Titan is now behind us, but the rich volume of data the spacecraft has collected will fuel scientific study for decades to come,” said Linda Spilker, the mission’s project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

 

Cassini Looking Home

Cassini looks back towards home. This is what we look like from Saturn, although I brightened the Moon up a little. The top image is the original released version and the second is one where I cropped and enlarged the section with the Earth and Moon for visibility.

Very nice indeed!

The release from NASA:

This view from NASA’s Cassini spacecraft shows planet Earth as a point of light between the icy rings of Saturn.

The spacecraft captured the view on April 12, 2017 at 10:41 p.m. PDT (1:41 a.m. EDT). Cassini was 870 million miles (1.4 billion kilometers) away from Earth when the image was taken. Although far too small to be visible in the image, the part of Earth facing toward Cassini at the time was the southern Atlantic Ocean.

Earth’s moon is also visible to the left of our planet in a cropped, zoomed-in version of the image (Figure 1).

The rings visible here are the A ring (at top) with the Keeler and Encke gaps visible, and the F ring (at bottom). During this observation Cassini was looking toward the backlit rings, making a mosaic of multiple images, with the sun blocked by the disk of Saturn.

Seen from Saturn, Earth and the other inner solar system planets are all close to the sun, and are easily captured in such images, although these opportunities have been somewhat rare during the mission. The F ring appears especially bright in this viewing geometry.

Image: NASA / Cassini Imaging Team

Soyuz 1

The first crewed Soyuz launch occurred 50 years ago today. The cosmonaut was Colonel Vladimir Komarov.

The mission ended in tragedy when the parachutes did not deploy correctly and Vladimir Komarov was killed, becoming the first person to perish on a space mission.

Last Titan Flyby

By this time the Cassini spacecraft has made its final close flyby of the Saturn moon Titan. This will allow one last look at the hydrocarbon lakes and surface of the moon, via radar of course, Titan is shrouded in a thick haze.

The encounter will alter the orbit of Cassini and start the final phase of the epic mission – The Grand Finale.

Here’s a video of how it will all came together in a video entitled “Crazy Engineering Astrodynamics”

Lights Out for JWST

It is lights out for the James Webb Space Telescope but in a good way.

I feel better about this than I did about the “shake-test“!

From NASA:
After completion of its vibration and acoustic testing in March, the James Webb Space Telescope – JWST – is shown here undergoing a detailed ‘lights out’ inspection in one of NASA’s cleanrooms at the Goddard Space Flight Center.

This is a special type of visual inspection to check for any forms of contamination. Both bright white LEDs and UV lights are used in order to better search for possible contamination, with the lights inside the cleanroom switched off to improve the contrast.

The low lighting means the image had to be taken with a longer than normal exposure time. This makes the technicians appear somewhat ghostly as they moved about the cleanroom during the exposure.

The image shows the segmented and gold-coated primary mirror of the telescope, which has a diameter of about 6.5 m when unfolded. It consists of 18 hexagonal segments, which will work together as one gigantic state-of-the-art mirror.

In order to fit inside the Ariane 5 rocket that will boost it into space, some segments will be folded, which will then open in orbit.

By the end of April, the telescope and the instruments will be shipped from NASA Goddard Space Flight Center in Maryland to Johnson’s Space Center in Texas where, over the course of the summer, it will go through final cryogenic-temperature testing.

JWST is joint project of NASA, ESA and the Canadian Space Agency, and is scheduled for launch in October 2018 from Europe’s Spaceport in Kourou, French Guiana.4\

Credit: NASA and C. Gunn

Launch Day — Replays

Here is the live link to the launch NASA astronaut Jack Fischer and  Fyodor Yurchikhin, of the Russian space agency Roscosmos to the International Space Station.

The launch time is 07:13 UTC /  03:13 EDT from the Baikonur Cosmodrome in Kazakhstan (13:13 local time).  Too early?  No worries I will put a video replay up.  HOWEVER if you can make it back here by 13:23 UTC / 09:23 EDT you will be able to see the Soyuz TM 04 dock to the ISS – YES, just six hours later.

Here’s the launch replay:

And the docking replay: