NASA’s Juno probe Gets Gravity Speed Boost during Earth Flyby But Enters ‘Safe Mode’

The first color reconstruction of the Moon by Adam Hurcewicz

Developing story – NASA’s Juno-bound Jupiter orbiter successfully blazed past Earth this afternoon (Oct. 9) and gained its huge and critical gravity assisted speed boost that’s absolutely essential to reach the Jovian system in 2016.

However, Juno’s project manager Rick Nybakken told me moments ago that the Juno spacecraft unexpectedly entered ‘safe mode’ during the fly by maneuver and the mission teams are assessing the situation.

But the very good news is “Juno is power positive at this time. And we have full command ability,” said Nybakken in an exclusive phone interview with me.

“After Juno passed the period of Earth flyby closest approach at 12:21 PM PST [3:21 PM EDT] and we established communications 25 minutes later, we were in safe mode,” Nybakken told me. Nybakken is the Juno mission project manager at NASA’s Jet Propulsion Lab in Pasadena, CA.

Furthermore, the Earth flyby did place the $1.1 Billion Juno spacecraft exactly on course for Jupiter as intended.

“We are on our way to Jupiter as planned!”

“None of this affected our trajectory or the gravity assist maneuver – which is what the Earth flyby is.”

Juno’s closest approach was over South Africa at about 500 kilometers (350 miles).

“Juno hit the target corridor within 2 km of the aim point,” Nybakken elaborated to Universe Today.

Juno needs the 16,330 mph velocity boost from the Earth swingby because the Atlas V launcher was not powerful enough to hurtle the 8000 pound (3267 kg) craft fast enough on a direct path to Jupiter.

And the team is in full radio contact with the probe. Safe mode is a designated protective state.

“Prior to the eclipse, which was a few minutes earlier than closest approach, the spacecraft was ‘nominal’. When we came out of the eclipse Juno was in safe mode,” Nybakken stated.

“We are going through safe mode diagnostics steps right now.”

“We have established full uplink and downlink. And we have full command ability of the spacecraft.”

First JunoCam image of the day! Taken at 11:07 UTC when Juno was 206,000 Kilometers from the Moon.
First JunoCam image of the day! Taken at 11:07 UTC when Juno was 206,000 Kilometers from the Moon.

Speed boosting slingshots have been used on numerous planetary missions in the past

The spacecraft’s power situation and health is as good as can be expected.

“Juno is power positive at this time and sun pointed and stable. So we are very pleased about that,” Nybakken explained.

I asked if Juno had ever entered ‘safe mode’ before?

“We have never been in safe mode before. We are in a safe, stable state.”

“We are investigating this,” said Nybakken.

Credit: NASA/JPL
Credit: NASA/JPL

Today’s (Oct. 9) Earth flyby is the only time the spacecraft experiences an eclipse period during Juno’s entire five year and 1.7 Billion mile (2.8 Billion km) trek to Jupiter, the largest planet in our solar system.

When it finally arrives at Jupiter on July 4, 2016, Juno will become the first polar orbiting spacecraft at the gas giant.

NASA’s Juno spacecraft blasted off atop an Atlas V rocket two years ago from Cape Canaveral Air Force Station, FL, on Aug. 5, 2011 on a journey to discover the genesis of Jupiter hidden deep inside the planet’s interior.

Juno soars skyward to Jupiter on Aug. 5, 2013 from launch pad 41 at Cape Canaveral Air Force Station at 12:25 p.m. EDT. View from the VAB roof. Credit: Ken Kremer/kenkremer.com
Juno soars skyward to Jupiter on Aug. 5, 2011 from launch pad 41 at Cape Canaveral Air Force Station at 12:25 p.m. EDT. View from the VAB roof. Credit: Ken Kremer/kenkremer.com
The science team had also hoped to use the on board JunoCam imager to make a cool and unprecedented movie of Earth as it approached from the sunlit side – showing the passage as though you were a visitor from outer space.

I had an inkling that something might be amiss this afternoon when no images of Earth appeared on the Juno mission website.

So I asked the status.

“We don’t know yet if any images of Earth were collected. We hope to know soon.”

Juno flew past the Moon before the gravity assist slingshot with Earth. And it did manage to successfully capture several lunar images. See the images herein.

Read more about Juno in my flyby preview story – here.

Note: Due to the continuing chaos resulting from the US government partial shutdown caused by gridlocked politico’s in Washington DC, NASA public affairs remains shut down and is issuing no official announcements on virtually anything related to NASA! This pertains to Juno’s flyby, LADEE’s lunar arrival on Oct. 6, MAVEN’s upcoming launch in November, Cygnus at the ISS, and more!

Stay tuned here for continuing Juno, LADEE, MAVEN and more up-to-date NASA news.

Ken Kremer

NASA’s Juno Jupiter-bound space probe will fly by Earth for essential speed boost on Oct 9, 2013. Credit: NASA/JPL
NASA’s Juno Jupiter-bound space probe will fly by Earth for essential speed boost on Oct 9, 2013. Credit: NASA/JPL

The Big Dipper Like You’ve Never Seen It Before!

Junocam image of the stars that make up the "Big Dipper" asterism

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All right, it may look just like any other picture you’ve ever seen of the Big Dipper. Maybe even a little less impressive, in fact. But, unlike any other picture, this one was taken from 290 million km away by NASA’s Juno spacecraft en route to Jupiter, part of a test of its Junocam instrument!  Now that’s something new concerning a very old lineup of stars!

“I can recall as a kid making an imaginary line from the two stars that make up the right side of the Big Dipper’s bowl and extending it upward to find the North Star,” said Scott Bolton, principal investigator of NASA’s Juno mission. “Now, the Big Dipper is helping me make sure the camera aboard Juno is ready to do its job.”

Diagram of the Juno spacecraft (NASA/JPL)

The image is a section of a larger series of scans acquired by Junocam between 20:23 and 20:56 UTC (3:13 to 3:16 PM EST) on March 14, 2012. Still nowhere near Jupiter, the purpose of the imaging exercise was to make sure that Junocam doesn’t create any electromagnetic interference that could disrupt Juno’s other science instruments.

In addition, it allowed the Junocam team at Malin Space Science Systems in San Diego, CA to test the instrument’s Time-Delay Integration (TDI) mode, which allows image stabilization while the spacecraft is in motion.

Because Juno is rotating at about 1 RPM, TDI is crucial to obtaining focused images. The images that make up the full-size series of scans were taken with an exposure time of 0.5 seconds, and yet the stars (brightened above by the imaging team) are still reasonably sharp… which is exactly what the Junocam team was hoping for.

“An amateur astrophotographer wouldn’t be very impressed by these images, but they show that Junocam is correctly aligned and working just as we expected”, said Mike Caplinger, Junocam systems engineer.

As well as the Big Dipper, Junocam also captured other stars and asterisms, such as Vega, Canopus, Regulus and the “False Cross”. (Portions of the imaging swaths were also washed out by sunlight but this was anticipated by the team.)

These images will be used to further calibrate Junocam for operation in the low-light environment around Jupiter, once Juno arrives in July 2016.

Read more about the Junocam test on the MSSS news page here.

As of May 10, Juno was approximately 251 million miles (404 million kilometers) from Earth. Juno has now traveled 380 million miles (612 million kilometers) since its launch on August 5, 2011 and is currently traveling at a velocity of 38,300 miles (61,600 kilometers) per hour relative to the Sun.

Watch a video of the Juno launch here, taken by yours truly from the press site at Kennedy Space Center!