JUICE Prepares for a first of its kind double-flyby next year.
A Jupiter-bound mission adjusted its course last week…for a rendezvous with Earth. The European Space Agency’s (ESA) Jupiter Icy moons Explorer (JUICE) fired its thrusters for 43 minutes on Friday, November 17th. This sets the mission up for a first of its kind double-flyby next year on August 23rd, as it passes the Moon and then the Earth to pick up momentum.
As it swings by Earth NASA’s first ever asteroid sample return mission, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer), will pass only 11,000 miles (17,000 kilometers) above Earth just before 12:52 p.m. EDT on Friday.
And NASA is asking the public to try and ‘Catch It If You Can’ – by waving hello and/or taking snapshots during and after the probes high speed flyby.
OSIRIS-REx will be approaching Earth at a velocity of about 19,000 mph on Friday as it begins flying over Australia during the Earth Gravity Assist (EGA) maneuver.
Since blastoff from the Florida Space Coast on Sept. 8, 2016 the probe has already racked up almost 600 million miles on its round trip journey from Earth and back to set up Friday’s critical gravity assist maneuver to Bennu and back.
As OSIRIS-REx continues along its flight path the spacecraft will reach its closest point to Earth over Antarctica, just south of Cape Horn, Chile. It will gain a velocity boost of about 8400 mph.
The spacecraft will also conduct a post flyby science campaign by collecting images and science observations of Earth and the Moon four hours after closest approach to calibrate its five science instruments.
The allure of Bennu is that it is a carbon rich asteroid – thus OSIRIS-REx could potentially bring back samples infused with the organic chemicals like amino acids that are the building blocks of life as we know it.
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation,” OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in a prelaunch interview with the spacecraft in the cleanroom at NASA’s Kennedy Space Center.
The do or die gravity assist plunge is absolutely essential to set OSIRIS-REx on course to match the asteroid’s path and speed when it reaches the vicinity of asteroid Bennu a year from now in October 2018.
“The Earth Gravity Assist is a clever way to move the spacecraft onto Bennu’s orbital plane using Earth’s own gravity instead of expending fuel,” says Lauretta, of the University of Arizona, Tucson.
Bennu’s orbit around the Sun is tilted at a six-degree inclination with respect to Earth’s orbital plane.
The asteroid is 1,614-foot (500 m) in diameter and crosses Earth’s orbit around the sun every six years.
Numerous NASA spacecraft – including NASA’s just completed Cassini mission to Saturn – utilize gravity assists around a variety of celestial bodies to gain speed and change course to save vast amounts of propellant and time in order to accomplish science missions and visit additional target objects that would otherwise be impossible.
The flyby will be a nail-biting time for NASA and the science team because right afterwards the refrigerator sized probe will be out of contact with engineers – unable to receive telemetry for about an hour.
“For about an hour, NASA will be out of contact with the spacecraft as it passes over Antarctica,” said Mike Moreau, the flight dynamics system lead at Goddard, in a statement.
“OSIRIS-REx uses the Deep Space Network to communicate with Earth, and the spacecraft will be too low relative to the southern horizon to be in view with either the Deep Space tracking station at Canberra, Australia, or Goldstone, California.”
NASA says the team will regain communication with OSIRIS-REx roughly 50 minutes after closest approach over Antarctica at about 1:40 p.m. EDT.
The post flyby science campaign is set to begin at 4:52 p.m. EDT, Friday, Sept. 22.
The OSIRIS-Rex spacecraft originally departed Earth atop a United Launch Alliance Atlas V rocket under crystal clear skies on September 8, 2016 at 7:05 p.m. EDT from Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida.
Everything with the launch went exactly according to plan for the daring mission boldly seeking to gather rocks and soil from carbon rich Bennu.
OSIRIS-Rex is equipped with an ingenious robotic arm named TAGSAM designed to collect at least a 60-gram (2.1-ounce) sample and bring it back to Earth in 2023 for study by scientists using the world’s most advanced research instruments.
“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu,” OSIRIS-Rex Principal Investigator Dante Lauretta told me in the prelaunch interview in the KSC cleanroom with the spacecraft as the probe was undergoing final launch preparations.
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation.”
“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”
NASA and the mission team is also inviting the public to get engaged by participating in the Wave to OSIRIS-REx social media campaign.
“Individuals and groups from anywhere in the world are encouraged to take photos of themselves waving to OSIRIS-REx, share them using the hashtag #HelloOSIRISREx and tag the mission account in their posts on Twitter (@OSIRISREx) or Instagram (@OSIRIS_REx).
Participants may begin taking and sharing photos at any time—or wait until the OSIRIS-REx spacecraft makes its closest approach to Earth at 12:52p.m. EDT on Friday, Sept. 22.”
The probe’s flight path during the flyby will pass through the ring of numerous satellites orbiting in geosynchronous orbit, but none are expected to be within close range.
Watch for Ken’s continuing onsite NASA mission and launch reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Juno Portrait of Earth
This false color composite shows more than half of Earth’s disk over the coast of Argentina and the South Atlantic Ocean as the Juno probe slingshotted by on Oct. 9, 2013 for a gravity assisted acceleration to Jupiter. The mosaic was assembled from raw images taken by the Junocam imager. Credit: NASA/JPL/SwRI/MSSS/Ken Kremer/Marco Di Lorenzo
See below a gallery of Earth from Juno[/caption]
During a crucial speed boosting slingshot maneuver around Earth on Oct. 9, NASA’s Jupiter-bound Juno probe snapped a dazzling gallery of portraits of our Home Planet over the South American coastline and the Atlantic Ocean. See our mosaics of land, sea and swirling clouds above and below, including several shown in false color.
But an unexpected glitch during the do or die swing-by sent the spacecraft into ‘safe mode’ and delayed the transmission of most of the raw imagery and other science observations while mission controllers worked hastily to analyze the problem and successfully restore Juno to full operation on Oct. 12 – but only temporarily!
Because less than 48 hours later, Juno tripped back into safe mode for a second time. Five days later engineers finally recouped Juno and it’s been smooth sailing ever since, the top scientist told Universe Today.
“Juno is now fully operational and on its way to Jupiter,” Juno principal investigator Scott Bolton told me today. Bolton is from the Southwest Research Institute (SwRI), San Antonio, Texas.
“We are completely out of safe mode!”
With the $1.1 Billion Juno probe completely healthy once again and the nail-biting drama past at last, engineers found the time to send the stored photos and research data back to ground station receivers.
“The science team is busy analyzing data from the Earth flyby,” Bolton informed me.
The amateur image processing team of Ken Kremer and Marco Di Lorenzo has stitched together several portraits from raw images captured as Juno sped over Argentina, South America and the South Atlantic Ocean and within 347 miles (560 kilometers) of the surface. We’ve collected the gallery here for all to enjoy.
Several portraits showing the swirling clouds and land masses of the Earth’s globe have already been kindly featured this week by Alan Boyle at NBC News and at the Daily Mail online.
Raw images from the Junocam camera are collected in strips – like a push broom. So they have to be carefully reconstructed and realigned to match up. But it can’t be perfect because the spacecraft is constantly rotating and its speeding past Earth at over 78,000 mph.
So the perspective of Earth’s surface features seen by Junocam is changing during the imaging.
And that’s what is fascinating – to see the sequential view of Earth’s beautiful surface changing as the spacecraft flew over the coast of South America and the South Atlantic towards Africa – from the dayside to the nightside.
It’s rare to get such views since only a few spacecraft have swung by Earth in this manner – for example Galileo and MESSENGER – on their way to distant destinations.
Coincidentally this week, the Cygnus cargo carrier departed the ISS over South America.
Fortunately, the Juno team knew right from the start that the flyby of Earth did accomplish its primary goal of precisely targeting Juno towards Jupiter – to within 2 kilometers of the aim point, despite going into safe mode.
“We are on our way to Jupiter as planned,” Juno Project manager Rick Nybakken, told me in a phone interview soon after the flyby of Earth. Nybakken is from NASA’s Jet Propulsion Lab in Pasadena, CA.
“None of this affected our trajectory or the gravity assist maneuver – which is what the Earth flyby is,” he said.
It also accelerated the ships velocity by 16,330 mph (26,280 km/h) – thereby enabling Juno to be captured into polar orbit about Jupiter on July 4, 2016.
The safe mode did not impact the spacecraft’s trajectory one smidgeon!
It was likely initiated by an incorrect setting for a fault protection trigger for the spacecraft’s battery when Juno was briefly in an eclipse during the flyby.
Nybakken also said that the probe was “power positive and we have full command ability,” while it was in safe mode.
Safe mode is a designated fault protective state that is preprogrammed into spacecraft software in case something goes amiss. It also aims the craft sunwards thereby enabling the solar arrays to keep the vehicle powered.
The Earth flyby maneuver was necessary because the initial Atlas V rocket launch on Aug. 5, 2011 from Cape Canaveral Air Force Station, FL was not powerful enough to place Juno on a direct trajectory flight to Jupiter.
As of today, Juno is more than was 6.7 million miles (10.8 million kilometers) from Earth and 739 million miles (7.95 astronomical units) from Jupiter. It has traveled 1.01 billion miles (1.63 billion kilometers, or 10.9 AU) since launch.
With Juno now on course for our solar system’s largest planet, there won’t be no any new planetary images taken until it arrives at the Jovian system in 2016. Juno will then capture the first ever images of Jupiter’s north and south poles.
We have never seen Jupiter’s poles imaged from the prior space missions, and it’s not possible from Earth.
During a year long mission at Jupiter, Juno will use its nine science instruments to probe deep inside the planet to reveal its origin and evolution.
“Jupiter is the Rosetta Stone of our solar system,” says Bolton. “It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary — to interpret what Jupiter has to say.”
Based on what we’ve seen so far, Junocam is sure to provide spectacular views of the gas giants poles and cloud tops.
Psst! Live in South Africa and read Universe Today? Then you might just get a peak at the Juno spacecraft as it receives a boost from our fair planet on the evening of October 9th, 2013.
Launched from Cape Canaveral Air Force Station on August 5th, 2011 atop an Atlas 5 rocket in a 551 configuration, Jupiter-bound Juno is approaching the Earth from interior to its orbit over the next month. Its closest approach to the Earth during its October 9th flyby will occur at 19:21 Universal Time (UT) which is 3:21 PM Eastern Daylight Saving Time. The spacecraft will pass 559 kilometres over the South Atlantic to a point 200 kilometres off of the southeastern coast of South Africa at latitude -34.2° south & longitude 34° east.
For context, this is just about 25% higher than the International Space Station orbits at an average of 415 kilometres above the Earth. The ISS is 108.5 metres across on its longest dimension, and we wouldn’t be surprised if Juno were a naked eye object for well placed observers watching from a dark sky site around Cape Town, South Africa. Especially if one of its three enormous 8.9 metre long solar panels were to catch the Sun and flare Iridium-style!
Two minutes before closest approach, Juno will experience the only eclipse of its mission, passing into the umbra of Earth’s shadow for about 20 minutes. Chris Peat at Heavens-Above also told Universe Today that observers in India are also well-placed to catch sight of Juno with binoculars after it exits the Earth’s shadow.
Juno passed its half-way mark to Jupiter last month on August 12th when the “odometer clicked over” to 9.464 astronomical units. Juno will enter orbit around Jupiter on July 4th, 2016. Juno will be the second spacecraft after Galileo to permanently orbit the largest planet in our solar system.
Catching a flyby of Juno will be a unique event. Unfortunately, the bulk of the world will miss out, although you can always vicariously fly along with Juno with Eyes on the Solar System. Juno is currently moving about 7 km/s relative to the Earth, and will move slightly faster than the ISS in its apparent motion across the sky from west to east before hitting Earth’s shadow. This slingshot will give Juno a 70% boost in velocity to just under 12km/s relative to Earth, just slower than Pioneer 10’s current motion relative to the Sun of 12.1km/s.
At that speed, Juno will be back out past the Moon in about 10 hours after flyby. There’s a chance that dedicated imagers based along North American longitudes could still spy Juno later that evening.
Juno approaches the Earth from the direction of the constellation Libra and will recede from us in the direction of the constellation Perseus on the night of October 9th.
There’s also a precedent for spotting such flybys previous. On August 18th, 1999, NASA’s Cassini spacecraft made a flyby of the Earth at 1,171 kilometres distant, witnessed by observers based in the eastern Pacific region. Back then, a fuss had been raised about the dangers that a plutonium-powered spacecraft might posed to the Earth, should a mis-calculation occur. No such worries surround Juno, as it will be the first solar-powered spacecraft to visit the outer solar system.
And NASA wants to hear about your efforts to find and track Juno during its historic 2013 flyby of the Earth. JPL Horizons lists an ephemeris for the Juno spacecraft, which is invaluable for dedicated sky hunters. You can tailor the output for your precise location, then aim a telescope at low power at the predicted right ascension and declination at the proper time, and watch. Precise timing is crucial; I use WWV shortwave radio broadcasting out of Fort Collins, Colorado for ultra-precise time when in the field.
As of this writing, there are no plans to broadcast the passage of Juno live, though I wouldn’t be surprised if someone like Slooh decides to undertake the effort. Also, keep an eye on Heavens-Above, as they may post sighting opportunities as well. We’ll pass ‘em along if they surface!
Late Breaking: And surface they have… a page dedicated to Juno’s flyby of Earth is now up on Heavens-Above.
Juno is slated to perform a one year science mission studying the gravity and magnetic field of Jupiter as well as the polar magnetosphere of the giant planet. During this time, Juno will make 33 orbits of Jupiter to complete its primary science mission. Juno will study the environs of Jupiter from a highly inclined polar orbit, which will unfortunately preclude study of its large moons. Intense radiation is a primary hazard for spacecraft orbiting Jupiter, especially one equipped with solar panels. Juno’s core is shielded by one centimetre thick titanium walls, and it must thread Jupiter’s radiation belts while passing no closer than 4,300 kilometres above the poles on each pass. One run-in with the Io Plasma Torus would do the spacecraft in. Like Galileo, Juno will be purposely deorbited into Jupiter after its primary mission is completed in October 2017.
If you live in the right location, be sure to check out Juno as it visits the Earth, one last time. We’ll keep you posted on any live broadcasts or any further info on sighting opportunities as October 9th draws near!
– Got pics of Juno on its flyby of the Earth? Send ’em in to Universe Today!
– You can also follow the mission on Twitter as @NASAJuno.