Back in 2010, we were sad to hear that JAXA’s Akatsuki orbiter experienced a malfunction during its attempt to insert itself into orbit around Venus. A planned twelve minute engine burn ended prematurely after about only three minutes, the result of salt formation causing a fault in a check valve. You might expect that that would have spelled the end to the mission, and Akatsuki would have spent eternity orbiting the Sun. Fortunately, JAXA would get a second chance to try their insertion effort again, but they’d have to wait nearly five years for both the craft and Venus to be in the right places for the attempt.
Orbit control test and maneuvers were conducted in 2011, and then again in 2015, setting the stage for an orbit insertion attempt. Tests showed that Akatsuki’s Orbital Maneuver Engine (OME), its main engine, couldn’t provide the thrust needed for the second insertion attempt. Hope fell to the craft’s attitude-adjustment engines.
65 kg of oxidizer fuel that would have been used by the no-longer-functional main engine was dumped to lighten the craft and allow it to be more maneuverable. In December, 2015, exactly five years after the first attempt to make orbit, four of the spacecraft’s secondary attitude control thrusters burned for 20 minutes and 33 seconds, slowing the spacecraft enough to be captured by Venus’s gravitational hold. The attempt was a success. Akatsuki entered Venusian orbit and began to conduct its mission objectives.
The final orbit is much further (between 4,000 km and 370,000 km versus the planned 300 km to 80,00 km) from our sister planet than originally planned. Instead of orbiting Venus once every 30 hours, Akatsuki orbits once every 9 days.
Diagram showing Akatuski’s planned and actual orbits – Credit: JAXA/Nature
So, while not exactly as planned, Akatsuki is still able to conduct great science. Akatsuki has already observed an interesting atmospheric gravity wave, peered through the clouds in infrared to reveal an equatorial jet, and sent back stunning images of our closest planetary neighbor.
False color image of cloud patterns on the night side of Venus taken by the Akatsuki’s IR2 camera. Thicker clouds are expressed as darker because thick clouds hamper infrared lights coming from the lower layer of the atmosphere. – Source: JAXA/PLANET-C Project Team
It’s September and a wonderful time to enjoy the night sky. In northern latitudes, the length of night is generally outpacing the upcoming winter chill. Spring and Fall are great times to become reacquainted with the cosmos.
Here’s a brief run-down of what to expect in the September skies (note: this information is tailored to those of us in the Northern Hemisphere).
What’s that planet?:
If it’s in the evening, it’s most likely Jupiter. If it’s in the morning, you might be seeing Venus, Mercury or Mars.
This month, Jupiter is its bold, bright self, but it’s tracking fairly close to the Sun and setting in the southwest. You’ll see it shortly after sundown, earlier and earlier the further north you are. In October, Jupiter will be outside of our view until its return in November. On September 21 and 22, Jupiter will appear very near to a thin crescent Moon. Saturn is also up during September nights, though you’ll want to consult a star chart or skymap app to find it due to it being hard to distinguish from stars. Speaking of Saturn, September 15 marks the grand finale of the Cassini spacecraft. After 20 years of astonishing service, Cassini will plunge into Saturn’s atmosphere and end one of the most successful space missions imagined.
On September mornings, keep an eye out for Venus, Mars, and Mercury. Venus is hard to miss, it’s the brightest object in the sky following the Sun and Moon. Keep an eye to the east about two hours before sunrise (closer to sunrise the later we get into the month) for our bright sister planet.
If you’re fortunate enough to live on the mid-northern latitudes, you might get to witness a fantastic conjunction of Mercury and Mars. (If you’re as far north as Alaska, you’ll need a clear view of the horizon.) On September 16, Mercury and Mars appearing extremely close to each other in the morning sky. Use this website to get a custom report for your viewing location.
If you need help finding out when a planet rises and sets for your location, this website is fairly indispensable.
2004 transit of Venus through a small telescope. Click image for source.
Next Tuesday, June 5th (June 5th in North America / June 6 eastern continents), you’ll have the opportunity to observe something that you’re extremely unlikely to ever see again. Over the course of a few hours, Venus will cross in front of the Sun from the vantage point of Earth. Venus will appear as a small black dot against the bright blazing disc of the Sun. Just like the annular eclipse from a couple of weeks ago, it is NOT SAFE to view this event directly. Here are a few ways to view it:
Disposable solar shade glasses – This is the cheapest and simplest method. These are the same glasses you would use to view a solar eclipse. They’re generally made of cardboard and have extremely dark film for lenses. When looking through them, you cannot see anything except for something as bright as the Sun. If you can see the surrounding landscape through them, they are NOT dark enough and you are at great risk of damaging your eyes.
Pinhole projection – If you’ve got clear skies and an overhead Sun, you can project the image of the Sun (and transit) using a simple pinhole projector. This can be as simple as a piece of paper with a hole poked in it, to a more elaborate and larger projector. Feel free to be creative, as long as you do it safely. Here are some sources for pinhole project ideas: Cosmos Magazine / TransitOfVenus.org / Exploratorium
Binocular/Telescope projection – You can also project a magnified view of the transit by using a pair of binoculars or a small telescope. Here, you want to point the objective lens (the big lens away from the eyepiece) at the Sun, let the light go through the binoculars/telescope and project that image onto a shaded piece of paper. Experiment with different distances until you get everything in focus. Note, that doing this method for a significant amount of time can damage the optics in your binoculars or telescope.
Webcast – If the clouds have you down or the transit occurs during your night time where you live, you can still watch the event unfold from what will certainly be a number of online webcasts. My friends at Cosmoquest will be hosting a Google+ Hangout with various feeds of the transit, and Slooh will make an event out of it as well.
So now that you know how to look, you need to know when and where.
[Map showing where the 2012 Venus transit will be visible from. Source: NASA / Click for larger view.]
Being an amateur astronomer in Alaska (especially along the coast) is the true definition of optimism. There are a lot of clouds year-round, never-ending sunlight during the Summer, and frigidly cold winters that make skygazing a test of tolerance and wills. That said, on those few nights where the clouds have retreated, it’s dark, and above zero… those nights are a-maz-ing. Coincidentally, Alaska is a prime viewing location for the 2012 transit of Venus — in fact, the entire event will be viewable from up here. Ironically, I’ll be out of the state during the transit and will only be able to catch it during a North Dakotan sunset (which sounds pretty, anyhow).
For the most accurate information for your location, there are a handful of resources. There are free iPhone and Android apps for your smartphone. Additionally, if you can find your location on a map this webpage is a fantastic guide. An example of how it varies from place to place:
My home in Kenai, Alaska (June 5th):
Venus crosses into the limb of the Sun at 2:06pm local time. Approximately 20 minutes later, Venus is fully within the disc of the Sun. It will slowly make its way across the face of the Sun over the next 6 hours, reaching the opposite limb at around 8:30pm local time. At 8:48, the show is over with the Sun still high in the sky.
Where I’ll be in North Dakota (June 5th):
The transit will begin at 5:04pm local time. By 8:27pm local time, Venus will be at the center-point of its transit. Around an hour later, the Sun will set, taking the transiting Venus with it.
The bottom line is, due to the duration of the event you should be able to get at least a glimpse of it from anywhere in North America, to a varying degree as shown above. And you’ll definitely want to make every opportunity to see it, because it will quite likely be the last time you have the chance — unless, of course, you plan on being alive for another 105 years (and still have the eyesight to see it!). That’s right, this will not occur again until 2117 — so this is your chance.
Have you seen the wondrous show that’s been taking place in the night sky recently? Maybe you noticed what appeared to be some especially bright stars, glittering near a crescent Moon. Perhaps you haven’t been looking up at the night sky lately (shame on you) or conditions have been too cloudy to give it a look (I live in a coastal city in Alaska, I feel your pain). Whether you’re looking or not, there’s a fantastic conjunction taking place, starring (pardon the pun!) the Moon, Jupiter, and Venus.
I took the following photo shortly after sunset on February 28, 2012, from within Joshua Tree National Park. Unfortunately, I didn’t have a lens to give me a wider field of view, but the top of a Yucca Plant provides a nice touch.
[Click image for larger and unlabeled version / Credit: Ryan Marquis/46BLYZ]
This cosmic spectacle will continue over the next few days, so get out and enjoy it while you can.
Also in the night sky this month:
While the Moon will have moved away from the planets, Venus and Jupiter will be within three degrees of each other on March 12. That’s approximately the same “width” as three fingertips held at arm’s length… The planets will appear quite close to one another!
Mars also refuses to be left out of this month’s planetary attention. Look for the red planet in the Eastern sky, just a few hours after the sun sets.
The Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (ISAS/JAXA) performed Venus orbit insertion maneuver (VOI-1) for the Venus Climate Orbiter “AKATSUKI” at 8:49 a.m. on December 7 (Japan Standard Time,) but, unfortunately, we have found that the orbiter was not injected into the planned orbit as a result of orbit estimation.
If control is able to be completely regained, there will be an opportunity to re-try entering Venusian orbit in five years — Akatsuki doesn’t have the fuel to hit the brakes and go back for another go at it.
This will mark the second JAXA planetary explorer that failed to complete its mission. Planet-B — dubbed “Nozomi” — failed to enter Mars orbit in 2003. That mission was abandoned, but the spacecraft is currently still active.
While the challenges of space travel have proven frustrating for JAXA, the agency cannot be said to not have its successes. Planet-A (“Suisei”) came within 151,000km of Halley’s Comet in 1986, as part of an international armada of probes sent to the renowned iceball during its last approach to our neck of the solar system.
Planet-A | Suisei
In addition to that, they have another very nifty, and successful, vehicle out there named IKAROS (“Interplanetary Kite-craft Accelerated by Radiation Of the Sun”). IKAROS is an experiment designed to demonstrate solar-sail technology as a means of traveling interplanetary space. IKAROS is an exciting little machine and I intend to devote an entire post to it in the near future.
Space exploration has come a long way in a very short amount of time, but we continually have these pesky failures to continually remind us that it is also very challenging. As frustrating as these complications may be, we can still appreciate the lessons learned and apply them to the success of future endeavors.
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