Asteroid? Rocket Stage? Whatever it is, WT1190F Plunges to Earth Tonight

No one’s 100% certain what WT1190F is — asteroid or rocket stage — but we are certain it will light up like a Roman candle when it re-enters Earth’s atmosphere around 6:20 Universal Time (12:20 a.m. CST) tomorrow morning Nov. 13. 


Animation by Jost Jahn of WT1190F’s final hours as it races across the sky coming down off the coast of Sri Lanka

As described in an earlier story at Universe Today, an object discovered by the Catalina Sky Survey on Oct 3rd and temporarily designated WT1190F is expected to burn up about 60 miles (100 km) off the southern coast of Sri Lanka overnight. The same team observed it twice in 2013. Based upon the evolution of its orbit, astronomers determined that the object is only about six feet (2-meters) across with a very low density,  making it a good fit for a defunct rocket booster, possibly one used to launch either one of the Apollo spacecraft or the Chinese Chang’e 3 lander to the Moon.

Below a plot of the last three orbits of WT1190F. The small red circle is the earth. The big green circle is the orbit of the moon, just to give some scale to the chart (click on it for a bigger version).
Below a plot of the last three orbits of WT1190F. The small red circle is the Earth. For scale, the large green circle is the orbit of the Moon. Notice that its final orbit takes straight into Earth. Credit: Bill Gray / Project Pluto

Additional observations of WT1190F have been made in the past few days confirming its re-entry later tonight. Checking the latest predictions on Bill Gray of Project Pluto’s page, the object will likely be visible from Europe about an hour before “touchdown”. To say it will be moving quickly across the sky is an understatement. Try about 3 arc minutes per second or 3° a minute! Very tricky to find and track something moving that fast.

Three 90-second exposures showing WT1190F zipping across the Rosette Nebula taken on Nov. 11, 2015 at the Konkoly Observatory in Hungary. Credit: Krisztián Sárneczky
Three 90-second exposures showing WT1190F zipping across the Rosette Nebula taken on Nov. 11, 2015 at the Konkoly Observatory in Hungary. Credit: Krisztián Sárneczky

58 minutes later, in the minute of time from 6:18 to 6:19 UT,  WT1190F will move one full hour of right ascension and plummet 34° in declination while brightening from magnitude +8 to +4.5. If you’d like to attempt to find and follow the object, head over to JPL’s Horizons site  for the latest ephemerides and orbital elements. At the site, make sure that WT1190F is in the Target Body line. If not, click Change and search for WT1190F in the Target Body field at the bottom of the window.

WT1190F Re-Entry Trajectory – Data courtesy of Bill Gray, Project Pluto
WT1190F re-Entry Trajectory. The object is expected to break up and fall harmlessly into the ocean. Credit: Bill Gray, Project Pluto

You’ll find updates at Bill Gray’s site. According to the most recent positions, the object will pass almost exactly in front of the Sun shortly before plunging into the ocean. Sri Lanka’s capital, Colombo, is expected to get the best views.

Because the mystery object’s arrival has been fairly well publicized, I hope to update you with a full report and photos first thing tomorrow morning. Like many of you, I wish I could see the show.

Flaming Space Junk Makes Jaws Drop in Australia

“It first looked like a plane with fire coming out of the tail.” — Aaron O.

“I have never seen anything like it. Big, bright and moving gently across sky – slower than a plane, not falling at all but moving across.” — Shannon H.

“Viewed from cockpit of aircraft at 37,000′. Was visible for two or three minutes.” — Landy T.

Flaming plane? Incandescent visitor from the asteroid belt? As the these comments from the AMS Fireball Log attest, the brilliant and s-l-o-w fireball that seared the sky over  southeastern Australia tonight was probably one of the most spectacular displays of re-entering space junk witnessed in recent years.

Ted Molczan, citizen satellite tracker and frequent contributor to the amateur satellite watchers SeeSat-L sitenotes that the timing and appearance almost certainly point to the decay or de-orbiting of the Russian Soyuz 2-1B rocket booster that launched the meteorological satellite Meteor M2 on July 8.


Meteor over New South Wales. Look closely near the end and you’ll see it disintegrate into small pieces.

The magnificent man-made meteor, weighing some 4,400 pounds (2,000 kg), was seen from Melbourne to Sydney across the states of Victoria and New South Wales around 10 p.m. Hundreds of people were stopped in their tracks.  Most noticed how slowly the fireball traveled and how long it continue to burn on the way down.

Spacecraft that reenter from either orbital decay or controlled entry usually break up at altitudes between 45-52 miles (84-72 km) traveling around 17,500 mph (28,000 km/hour) . Compression and friction from the ever-thickening air cause the craft, or in this case, the rocket booster, to slow down and heat up to flaming incandescence just like a hunk of space rock arriving from the asteroid belt. In both cases, we see a brilliant meteor, however manmade debris.

Jan 21, 2001, a Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East. The titanium motor casing, weighing about 70 kg, landed in Saudi Arabia about 240 km from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office
A Delta 2 third stage, known as a PAM-D, reentered the atmosphere over the Middle East on Jan. 21, 2001. The titanium motor casing, weighing about 154 lbs. (70 kg), landed in Saudi Arabia about 150 miles from the capital of Riyadh. Credit: NASA, Orbital Debris Program Office

Occasional meteoroids break apart in the atmosphere and scatter meteorites just as pieces of occasional satellites, especially large, heavy craft, can survive the plunge and land intact –  if a tad toasted.  Whether anything remains of Russian rocket stage or where exactly it fell is still unknown. Here are a few more photos of successful space junk arrivals.

The only person to be hit by manmade space debris was Lottie Williams in 1997.  She was unharmed. Credit: Tulsa World
The only person to be hit by manmade space debris was Lottie Williams in 1997. She was unharmed. Credit: Tulsa World

Reportedly, only one person has been struck by satellite debris. In 1997 Lottie Williams of Tulsa, Oklahoma was hit on the shoulder while walking by a small, twisted piece of metal weighing as much as a crushed soda can. It was traced back to the tank of a Delta II rocket that launched a satellite in 1996. I suppose it’s only a matter of time before someone else gets hit, but the odds aren’t great. More likely, you’ll see what alarmed and delighted so many southeastern Australians Thursday night: a grand show of disintegration.