Watch HTV-5 Chase the International Space Station From Your Backyard

A JAXA H-IIB rocket departs Tanegashima Space Center in a dramatic night shot. Image credit: JAXA/NASA TV

It’s away… and the hunt is on. The Japanese Space Agency’s H-II Transfer Vehicle Kounotori automated cargo spacecraft rocketed out of the Tanegashima Space Center today, headed for the ISS.

Loaded with over 6,000 kilograms of experiments and supplies, HTV-5 is on a five day odyssey that you can follow from your backyard, starting tonight. Kounotori stands for ‘white stork,’ or the purveyor of joyful things in Japanese, and in this instance, the name is appropriate, as the HTV-5 is delivering much needed supplies to the International Space Station.

HTV-5 during encapsulation. Credit: JAXA

Launch occurred this morning at 11:50 UT/7:50 AM EDT, hitting an instantaneous window to chase after the International Space Station for grapple and berthing on Monday.

Unlike the Progress and Soyuz spacecraft, which have the capability to rendezvous and dock with the ISS, the HTV-5 and Dragon spacecraft are grappled with the Canadian Space Agency’s Canadarm 2,  and stowed or ‘berthed’ in place.

Grapple with berthing to the nadir node of the Harmony module is set for Monday, August 24th, at 11:54 UT/7:54 AM EDT.

Unlike other vehicles that periodically visit the International Space Station, the HTV does not incorporate deployable solar panels, but instead, has panels wrapped around its body. This can also lend itself to some pretty bright flares as it passes overhead.

Grapple of HTV-4 by the Canadarm 2. Image credit: NASA/JAXA
Grapple of HTV-4 by the Canadarm 2. Image credit: NASA/JAXA

The H-IIB is a two stage rocket, and ground observers should keep an eye out for the second stage booster during ISS passes as well. Debris was also jettisoned during last weeks’ spacewalk, and there’s no word as of yet if this has reentered as well, though ground-spotters have yet to report any sightings. This is a typical EVA maneuver, and cosmonauts conducted the release in such a fashion as to pose no danger to the ISS or HTV. Debris jettisoned from the ISS typically reenters the Earth’s atmosphere after about a week or so.

Prospects for Seeing HTV-5 this Weekend

Grapple of the HTV-5 will occur Monday over central Asia. Keep in mind, the HTV-5 will have to perform several burns to reach the elevation of the ISS: this means its orbit will evolve daily. Heavens-Above and NASA’s Spot the Station tracker typically publish sighting predictions for cargo vehicles such as the HTV-5 along with ISS sighting opportunities online.

And we’ll be posting daily updates and maps as @Astroguyz on Twitter. We see the best prospects for spotting the ISS and HTV5 over the next few days leading up to Monday’s berthing are for latitudes 25-45 north (dusk) and latitudes 30-50 south (dawn). That covers a wide range of observers in Europe, North America, South Africa and Australia/New Zealand.

A capture of the passage of HTV-4. Image credit and copyright: Fred Locklear
A capture of the passage of HTV-4. Image credit and copyright: Fred Locklear

We’ve caught sight of JAXA’s HTV on previous missions, and contest to it being a conspicuous object.

Pro-tip: the trick to a successful sighting is to start watching early. The HTV-5 will be fainter than the brilliant ISS, but still visible to the naked eye at about magnitude +1 to +2 or so when directly overhead. The HTV-5 will follow the same orbital trace as the station. Spot the ISS and still don’t see HTV-5? Linger for a bit and keep watching after the ISS has passed, as the HTV might follow shortly. And the darker the skies you can find to carry out your HTV-5 vigil under, the better!

Aug 19
Initial estimations for the passage of the HTV-5 about 10 minutes ahead of the ISS on Wednesday, August 19th. Image credit: Orbitron

Here’s a sampling of ISS passes for Washington D.C. for the next few days:

Wednesday, August 19th: 8:46 PM EDT (Elevation 65 degrees NE)

Thursday, August 20th: 9:29 PM EDT (Elevation 23 degrees SW)

Friday, August 21st: 8:35 PM EDT (Elevation 48 degrees SW)

Clouded out? You can still watch the grapple and berthing action online courtesy of NASA TV.

Want more? Other orbital alumni that have placed a port of call at humanity’s orbital outpost include: SpaceX’s Dragon, the U.S. Space Shuttle fleet (excepting the Columbia orbiter), Progress, ATV, HTV, Soyuz, and Orbital Science’s Cygnus spacecraft. And while the shuttle and the European Space Agency’s ATV fleet are retired, you can follow the next launch of a crewed Soyuz (TMA-18M) on September 2nd from the Baikonur Cosmodrome on a four-orbit fast-track docking.

JAXA plans to launch one HTV a year, out to HTV-9 in 2019.

Good luck, and good sat-spotting… next time we park the Jeep Liberty in the garage, we’re going to refer to it as a ‘grapple and berthing…’ it just sounds cool.

Got a picture of the International Space Station and friends? Be sure to send ‘em in to Universe Today.

Getting Ready for “ISS All-Nighters” in June

The International Space Station as seen from the crew of STS-119. (Credit: NASA).

Never seen the International Space Station before? Now is a good time to try, as we enter into a very special time of year.

Starting at 12:30 Universal Time/8:30 AM EDT on Monday, June 3rd, the ISS will enter a phase of permanent illumination throughout the length of its orbit. The station will remain in sunlight and will not experience an orbital sunset until five days later, when it briefly dips into the Earth’s shadow on June 8th at 11:50 UT/ 7:50 AM EDT.

This sets us up for a wealth of visible passes worldwide. This unique phenomenon occurs as a product of the station’s highly inclined orbit. Tilted at 51.6° with respect to the Earth’s equator, its orbit can be oriented roughly perpendicular to the Sun within a few weeks of either solstice.

But whereas the December solstice favors multiple summer sightings for the southern hemisphere, the season near the  June solstice (which occurs this year on June 21st) favors northern latitudes. In fact, observers in the UK, southern Canada and the northern United States will be able to see multiple ISS passes in one night over the next week. Note that the ISS is nearly in full illumination now, and will remain so well into mid-June.

So, why was the ISS put into such a highly inclined orbit?

This orientation enables international partners to have access to the station from launch complexes worldwide. Whereas the shuttle launched on construction flights from Cape Canaveral at 28.5° north latitude, the Progress and crewed Soyuz missions depart from the Baikonur Cosmodrome in Kazakhstan located at 46° north. This resulted in some dramatic launches from the US Florida Space Coast, as the shuttle chased the ISS up the US Eastern Seaboard and was often visible minutes later crossing over the UK.

Though born of practicality, this happy circumstance also means that the ISS is visible to a wide swath of humanity located from 60° north latitude to 60° south. Only locales such as Antarctica, Greenland, and Iceland miss out.

I’m often asked how I know a moving star is a satellite and not an airplane. Aircraft flash, generating their own light, while satellites shine by reflected sunlight. This means that there’s a window of about an hour after sunset or before local sunrise that objects in low Earth orbit are still illuminated high overhead. In the early morning hours, if often seems as if someone has just “flipped on a switch” and satellites suddenly become visible across the sky.

And yes, satellites can flash as well, but in most instances, this is due to tumbling or the observer catching a glint of sunlight off of a reflective panel or surface just right. The Iridium constellation of satellites is known for this effect, but the ISS and Hubble Space Telescope can also flare in this fashion as well.

At 108.5 x 72.8 metres in size, the ISS is the largest man made object ever constructed in Earth orbit. Its unmistakable to spot as it passes overhead, shining at a maximum illumination brighter than the planet Venus at magnitude -5.2 when 100% illuminated.

Note the time the ISS is passing over your location and the direction its coming from and just start watching, no equipment required. It’s really as simple as that. Many prediction platforms exist for ISS passes. I’ve used Heavens-Above for over a decade now to spot ISS passes worldwide. Probably the simplest tracker out there is provided by Spaceweather. Just enter in your postal code and it kicks out an easy to decipher prediction. NASA also has a “Sighting Opportunities” webpage where you can choose your country and city to find out when the ISS will be passing over your location.

More advanced satellite trackers many want to check out CALSky which can also provide a list of transits of the ISS in front of the Sun or Moon from your location. I’ve managed to catch one each from my backyard utilizing it. I also like to use a free satellite tracking program known as Orbitron, which can be run on a laptop in the field away from an Internet connection.

Screenshot of the ISS orbital pass during full illumination next week. (Credit: Orbitron).
Screenshot of the ISS orbital pass during full illumination next week. (Credit: Orbitron).

Photographing a pass of the ISS is easy. Just do a wide field exposure with a DSLR camera on a tripod for 10-30 seconds and you’ll get a picture of the ISS streaking across the starry background. Be sure to use manual mode and either set the focus to infinity or focus on something bright such as Venus just prior to the pass. I generally take a series of test exposures prior to get the combination of ISO/f-stop settings correct for the current sky conditions.

A 20 second exposure of the ISS during a July 4th fireworks show in 2011. (Photo by Author).
A 20 second exposure of the ISS during a July 4th fireworks show in 2011. (Photo by Author).

I can just make out structure on the ISS with binoculars as it passes overhead. This appearance can vary greatly depending on its orientation. Sometimes, it looks like a close binary star. Other times it can appear box-shaped. Occasionally, it looks like a tiny luminous Star Wars TIE-fighter!

The ISS as imaged by Mike Weasner. Credit: The Cassiopeia Observatory).
The ISS as imaged by Mike Weasner. Credit: The Cassiopeia Observatory).

The station managers typically orient the huge solar arrays to provide a small amount of artificial shadow during phases of full illumination. The ISS extends ~45” across at closest approach, similar in apparent diameter to Saturn including its ring system.

You can even image the ISS through a telescope, with a little skill and luck. Many sophisticated mounts will track the ISS as it crosses the sky, or you can use our own low-tech method;

Be sure to check out an ISS pass coming to a sky near you!