The banner image, captured by NASA’s Juno spacecraft, might look like the one I used in my last Space Sunday update, but there is one important difference. The images used last time around had been captured by Juno on June as it approached the Jovian system on June 29th, five days before the craft had to complete a critical engine burn whilst almost scraping the planet’s cloud tops, to place itself in an extended orbit around Jupiter. The image above was captured on July 10th, as Juno headed away from Jupiter, having successfully completed the manoeuvre.
At the time the picture was captured, 17:30 UTC on July 10th, 2016, Juno was already 4.3 million kilometres (2.7 million miles) distant from the planet, and heading away from it at a relative velocity of 18,420 km / hour (11,446 mph) and decelerating under the influence of the Jupiter’s gravity.
Juno’s imaging system – JunoCam – had, along with other major systems aboard the craft, been shut down prior to the July 4th engine burn, both to conserve power – Juno had to turn its solar panels away from the Sun during the burn manoeuvre, limiting the available electrical power – and to protect them through the initial passage through Jupiter’s tremendous radiation fields. It wasn’t until July 6th that the instruments were all powered back up, and after testing them, the July 10th exercise was the first opportunity to have a look back at the Jovian system.
Juno will keep travelling outwards from Jupiter until the end of July, slowing to a relative velocity of just 1,939 km/h (1212 mph), before it starts to “fall” back towards the planet, making a second close flyby on August 27th. At this time, the craft will pass just 4,142 km (2,575 mi) above the Jovian cloud tops at a speed of 208,11 km/h (129,315 mph). More importantly, all of vehicle’s science instruments will remain powered-up, and JunoCam in particular should gain some stunning images of Jupiter during this second close pass.
To celebrate Juno’s arrival around Jupiter, NASA released a time-lapse video of the Jovian system as seen by the approaching spacecraft. It begins on June 12th with Juno 16 million km (10 million mi), and ends on June 29th, when JunoCam was shut down and Juno was 4.8 million km (3 million mi) distant.
Made possible by Juno’s high angle of approach into the Jovian system, it is the first close-up view of celestial harmonic motion we’ve ever had. Also, the 17-day duration of the movie means we see Callisto (flickering very faintly) make a full orbit around Jupiter, and get to see Ganymede, Europa and Io (counting inwards towards the planet) each experience eclipse as they pass through Jupiter’s shadow. Note that the flickering exhibited by the moons is an artefact of JunoCam, which is optimised to image bright features on Jupiter, rather than capturing the (relatively) dim pinpoints of the distant moons as they circle the planet.
Curiosity Resumes Operations as 2020 “Sister” Takes Shape
In my last update I reported that NASA Mars Science Laboratory, Curiosity, had entered a “safe” mode on July 2nd. On July 9th, the mission team successfully recovered the rover from this safe mode – a precautionary state the rover will set for itself should it detected an event which could damage its on-board systems – and then subsequently returned Curiosity to a fully operational status on July 11th.
The cause of the problem lay in a glitch in one of the modes by which images are transferred from the memory in some of the rover’s camera systems to its main computers. This generated a data mismatch warning, prompting the rover to active its “safe” mode and call Earth for assistance. Use of this particular data transfer mode between the identified camera systems and the computers is now being avoided in order to prevent a repeat of the problem.
Meanwhile, NASA’s next rover mission – designated Mars 2020 at present, as it will launch in the summer of that year to arrive on Mars in February 2021 – is taking shape. The basic vehicle will be based on the Curiosity class of rover, but will carry a different science suite and have somewhat different capabilities.
In particular, the new rover will carry an entirely new subsystem to collect and prepare Martian rocks and soil samples which can be stored in sample tubes. About 30 of these sample tubes will be deposited at select locations, so that they might be collected by a possible future automated mission and returned to Earth for direct analysis for evidence of past life on Mars and possible health hazards for future human missions.
Two science instruments mounted on the rover’s robotic arm will be used to search for signs of past life and determine where to collect samples by analysing the chemical, mineral, physical and organic characteristics of Martian rocks, while a suite of advanced camera systems will be housed on the vehicle’s mast. As with Curiosity, Mars 2020 will carry a comprehensive meteorological suite for monitoring the Martian environment and weather, together with a ground penetrating radar system for determining what is going on under the rover’s wheels.
Continue reading “Space Sunday: celestial harmonics, breathing air and singing for Pluto”