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Two Satellites Could Collide Tomorrow Night
www.popularmechanics.com ^ | Jan 28, 2020 | By Jennifer Leman

Posted on 01/28/2020 10:20:22 AM PST by Red Badger

What happens if the retired space telescope and former spy satellite crash into each other?

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Leo Labs, a venture-based company that monitors satellites in Low Earth Orbit, tweeted yesterday that it was tracking two satellites that will come within 15 to 30 meters of each other January 29, just before 6:40 p.m. EST. The two satellites are IRAS, a decommissioned NASA space telescope, and GGSE-4, a US Naval Research Lab intelligence satellite. They're set to sweep past each other in the skies above Pittsburgh at an altitude of about 559 miles above Earth's surface.

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LeoLabs, a company that monitors the trajectories of spacecraft in Low Earth Orbit, tweeted Monday afternoon that it was monitoring the close approach of two satellites that are likely to come within meters of each other on Wednesday, January 29. Were they to crash, the collision could send out a sprawling debris field, which could potentially impact other satellites in orbit.

The two satellites, NASA’s IRAS space telescope and the experimental U.S. Naval Research Lab satellite GGSE-4, will swing past each other at 6:39 p.m. EST at an altitude of about 559 miles in the skies above Pittsburgh, Pennsylvania. They’ll be hurtling along their orbit at a relative velocity of about 32,880 miles per hour and could swing within 50 feet of each other.

LeoLabs noted that, at the time of the tweet, the odds of a collision were about 1 in 100 and said the relatively large size of the two spacecraft increased the risk of a collision. “Events like this highlight the need for responsible, timely deorbiting of satellites and space sustainability moving forward,” the company tweeted.

NASA, the Netherlands Agency for Aerosace Programmes, and the U.K.'s Science and Engineering Research Council launched the Infrared Astronomical Satellite (IRAS) from Vandenberg Air Force Base in California on January 25, 1983. IRAS carried three scientific instruments: a survey array, a low resolution spectrometer and a chopped photometric channel.

For 10 months, the space telescope monitored the skies in infrared wavelengths. It discovered six new comets, charted our galaxy’s guts, and uncovered evidence of solid material—an indicator of planetary formation—around the stars Vega and Formalhaut. The 2103-pound telescope was put to pasture on November 21, 1983. image A model with the same design as U.S. Naval Research Lab satellite Poppy 5B. NRO

Meanwhile, the U.S. Naval Reconnaissance Office, the National Security Agency, and the Naval Research Lab launched the other spacecraft, GGSE-4 or POPPY 5b, from Vandenberg in 1967—one of a seven-satellite intelligence mission. Some information about the POPPY program was declassified in 2005. The 187-pound satellite has 59-foot-long gravity gradient booms that reach out into space—an obvious concern given the close distance in which the two satellites are projected to pass. It was decommissioned in 1972.

Scientists and space industry veterans founded LeoLabs in 2016 to better track and monitor the myriad satellites, spacecraft, and debris hurtling through Low Earth Orbit, according to its website. Based out of Menlo Park, California, the company has a worldwide network of phased-array radars that track objects in LEO in high definition.

As we’ve increasingly launched more and more spacecraft into Earth’s orbit, astronomers, engineers, and space industry experts have grown increasingly concerned about the Kessler Effect. Named for NASA space debris expert Don Kessler, the theory suggests a series of collisions between spacecraft in Earth’s orbit could spur a devastating series of chain reactions.

If there were enough impacts, the amount of space junk created would reach a critical mass, blanketing our planet in fog of debris and making it nearly impossible to safely launch spacecraft from Earth.

Former astronaut Ed Lu, who is LeoLabs’ vice president of strategic projects, put a call out to Pittsburgh-area amateur astronomers to train their telescopes on the sky tomorrow night. Needless to say, we’ll all be holding our breath, hoping these two satellites can slide past each other without incident.

A model with the same design as U.S. Naval Research Lab satellite Poppy 5B.

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IRAS (13777), the decommissioned space telescope launched in 1983, and GGSE-4 (2828), an experimental US payload launched in 1967.

(IRAS image credit: NASA)


TOPICS: Astronomy; History; Military/Veterans; Science
KEYWORDS: astronomy; ggse4; iras; pennsylvania; pittsburgh; science; spaceexploration; spacejunk
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To: webheart

It’s a two-dimensional problem. The collision cross section is determined by the projection of the respective satellites silhouettes onto the plane perpendicular to direction of their relative velocity at the moment of closest approach.

The third dimension, the dimension in the direction of the velocity doesn’t count because at some point the separation in that dimension *will* go to zero by definition, at exactly the moment of nearest approach. It does not influence whether or not there is a collision, only when. (You can assume that the satellites are not rotating during the duration of the collision event. If the velocity of rotation about its own body center were comparable to the orbital velocity, the centrifugal force would exceed 10,000 g’s and would already have torn the satellite apart.)


41 posted on 01/28/2020 11:02:12 AM PST by Lonesome in Massachussets (Every election, more or less, is an advance auction of stolen goods. - H. L. Mencken)
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To: Cold Heart
Hey you got chocolate on my peanut butter

You got peanut butter on my chocolate! Hey! Wait a minute....yum.

42 posted on 01/28/2020 11:02:22 AM PST by Bloody Sam Roberts (Gender-based outcomes don't matter if gender doesn't.)
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To: BenLurkin
Here's John Belushi to describe what could happen.


43 posted on 01/28/2020 11:02:44 AM PST by Larry Lucido
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To: gundog

Sunlight glinting off thousands of metal parts would need no oxygen..................


44 posted on 01/28/2020 11:03:26 AM PST by Red Badger (Against stupidity the gods themselves contend in vain.......... ..)
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To: Responsibility2nd

How about using them as ASAT target practice?


45 posted on 01/28/2020 11:07:13 AM PST by JimRed ( TERM LIMITS, NOW! Build the Wall Faster! TRUTH is the new HATE SPEECH.)
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To: webheart

“Even as close as 15 meters the odds of them actually colliding are astronomically against. 15 meters is bigger than either satellite and we are talking about 3 dimensions rather than 2.”

Pointing out that this is the problem that NMD had to solve with hit-to-kill warheads. Executing that last course adjustment to make impact — that’s the trick.


46 posted on 01/28/2020 11:15:46 AM PST by Tallguy (Facts be d@mned! The narrative must be protected at all costs!))
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To: webheart

“... and we are talking about 3 dimensions rather than 2.”

We are talking about two dimensions.


47 posted on 01/28/2020 11:27:39 AM PST by Born to Conserve
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To: Red Badger
All 3000 of them could collide. It doesn't get worrisome until they might or will.


"The difference between the almost right word and the right word is really a large matter - 'tis the difference between the lightning-bug and the lightning."
-- Mark Twain

48 posted on 01/28/2020 11:33:02 AM PST by Paal Gulli
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To: Red Badger
"What happens if the retired space telescope and former spy satellite crash into each other?"

Massive NASA/NSA orgasm...

49 posted on 01/28/2020 11:36:41 AM PST by SuperLuminal (Where is Sam Adams now that we desperately need him)
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To: Red Badger

If the powers that be know a satellite has a finite life span, why do they not build and program it to burn itself up in the atmosphere?

Instead there will be even more space junk floating around.


50 posted on 01/28/2020 11:39:47 AM PST by txnativegop (The political left, Mankinds intellectual and political hemlock)
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To: Red Badger

What happens if the retired space telescope and former spy satellite crash into each other?

you get a bigger telescope on the spy satellite?


51 posted on 01/28/2020 11:41:38 AM PST by PIF (They came for me and mine ... now its your turn)
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To: Red Badger
What happens if the retired space telescope and former spy satellite crash into each other?


52 posted on 01/28/2020 11:42:01 AM PST by DannyTN
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To: Red Badger
Events like this highlight the need for responsible, timely deorbiting of satellites and space sustainability moving forward,” the company tweeted.

Yes, of course. Not to mention gobs and gobs of money.

53 posted on 01/28/2020 11:46:15 AM PST by Texas Eagle (If it wasn't for double-standards, Liberals would have no standards at all -- Texas Eagle)
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To: Red Badger

Sounds like a job for The US Space Force. Shoot those suckers down.


54 posted on 01/28/2020 11:47:30 AM PST by Texas Eagle (If it wasn't for double-standards, Liberals would have no standards at all -- Texas Eagle)
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To: DannyTN

You get a satellite that can see the numbers on your watch....................


55 posted on 01/28/2020 12:04:38 PM PST by Red Badger (Against stupidity the gods themselves contend in vain.......... ..)
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To: txnativegop

They essentially let gravity do it.

Slow, very slow, but sure....................


56 posted on 01/28/2020 12:07:40 PM PST by Red Badger (Against stupidity the gods themselves contend in vain.......... ..)
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To: George from New England
If both are speeding along at close to the same speed

Per the article, they have a relative velocity of about 32,880 miles per hour. That implies they are in very different orbits. In fact, IRAS in a near polar orbit and GGSE-4 in a highly inclined orbit, their individual velocities of about 16,000 miles per hour can in fact sum up to the cited relative velocity if one is heading northward and the other southward. So if IRAS even catches a tiny bit of a GGSE-4 boom there can be significant debris flying around.

57 posted on 01/28/2020 12:12:54 PM PST by SFConservative
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To: txnativegop

It takes a lot of propellant to lower these satellites’ orbits sufficiently to reenter the atmosphere. Poppy was launched in 1967 and IRAS in 1983. Back then there were relatively few satellites and the collision/debris risk was minimal. Today the rule is that low earth orbit satellites should reenter no more than 25 years after they stop operating.


58 posted on 01/28/2020 12:22:51 PM PST by SFConservative
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To: SFConservative

I take it the 25 year rule relies on physics to pull the satellites into the atmosphere?


59 posted on 01/28/2020 12:24:46 PM PST by txnativegop (The political left, Mankinds intellectual and political hemlock)
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To: txnativegop

It relies on the tiny bit of drag that the satellites experience from the super thin atmosphere up there. As they get lower and lower the atmosphere density increases so the process accelerates gradually toward reentry. Satellites today typically save some fuel to lower their orbit partway at end of service life and then let drag take over from there. Some newer concepts inflate a balloon or other appendage at the end of satellite life to provide a larger drag cross-section and speed up the reentry process.


60 posted on 01/28/2020 12:32:03 PM PST by SFConservative
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