Still image taken from a movie, Space debris ? a journey to Earth, to be released April 18th, 2017. Credit: ESA
Orbital debris, otherwise known as “space junk”, is a major concern. This massive cloud that orbits the Earth is the result of the many satellites, platforms and spent launchers that have been sent into space over the years. And as time went on, collisions between these objects (as well as disintegrations and erosion) has created even more in the way of debris.
Sentinel-1 satellite, the first satellite to be launched as part of the ESA/EC's Copernicus program. Credit: ESA/ATG medialab
One of the worst things that can happen during an orbital mission is an impact. Near-Earth orbit is literally filled with debris and particulate matter that moves at very high speeds. At worst, a collision with even the smallest object can have catastrophic consequences. At best, it can delay a mission as technicians on the ground try to determine the damage and correct for it.
This was the case when, on August 23rd, the European Space Agency’s Sentinel-1A satellite was hit by a particle while it orbited the Earth. And after several days of reviewing the data from on-board cameras, ground controllers have determined what the culprit was, identified the affected area, and concluded that it has not interrupted the satellite’s operations.
The Sentinel-1A mission was the first satellite to be launched as part of the ESA’s Copernicus program – which is the worlds largest single earth observation program to date. Since it was deployed in 2014, Sentinel-1A has been monitoring Earth using its C-band Synthetic Aperture Radar, which allows for crystal clear images regardless of weather or light conditions.
Picturing obtained by one of the Sentinel-1A’s onboard cameras, showing the solar array before and after the impact of a millimeter-size particle on the second panel. Credit: ESA
In addition to tracking oil spills and mapping sea ice, the satellite has also been monitoring the movement of land surfaces. Recently, it provided invaluable insight into the earthquake in Italy that claimed at least 290 lives and caused widespread damage. These images were used by emergency aid organizations to assist in evacuations, and scientists have begun to analyze them for indications of how the quake occurred.
The first indication that something was wrong came on Tuesday, August 23rd, at 17:07 GMT (10:07 PDT, 13:07 EDT), when controllers noted a small power reduction. At the time, the satellite was at an altitude of 700 km, and slight changes in it’s orientation and orbit were also noticed.
After conducting a preliminary investigation, the operations team at the ESA’s control center hypothesized that the satellite’s solar wing had suffered from an impact with a tiny object. After reviewing footage from the on-board cameras, they spotted a 40 cm hole in one of the solar panels, which was consistent with the impact of a fragment measuring less than 5 mm in size.
However, the power loss was not sufficient to interrupt operations, and the ESA was quick to allay fears that this would result in any interruptions of the Sentinel-1A‘s mission. They also indicated that the object’s small size prevented them from advanced warning.
Artist’s impression of Sentinel-1A, showing its solar panels fully deployed. Credit and copyright: ESA–P. Carril, 2014
As Holger Krag – Head of the Space Debris Office at ESA’s establishment in Darmstadt, Germany – said in an agency press release:
“Such hits, caused by particles of millimeter size, are not unexpected. These very small objects are not trackable from the ground, because only objects greater than about 5 cm can usually be tracked and, thus, avoided by maneuvering the satellites. In this case, assuming the change in attitude and the orbit of the satellite at impact, the typical speed of such a fragment, plus additional parameters, our first estimates indicate that the size of the particle was of a few millimeters.
While it is not clear if the object came from a spent rocket or dead satellite, or was merely a tiny clump of rock, Krag indicated that they are determined to find out. “Analysis continues to obtain indications on whether the origin of the object was natural or man-made,” he said. “The pictures of the affected area show a diameter of roughly 40 cm created on the solar array structure, confirming an impact from the back side, as suggested by the satellite’s attitude rate readings.”
In the meantime, the ESA expects that Sentinel-1A will be back online shortly and doing the job for which it was intended. Beyond monitoring land movements, land use, and oil spills, Sentinel-1A also provides up-to-date information in order to help relief workers around the world respond to natural disasters and humanitarian crises.
The Sentinel-1 satellites, part of the European Union’s Copernicus Program, are operated by ESA on behalf of the European Commission.
The chip in the ISS' Cupola window, photographed by astronaut Tim Peake. Credit: ESA/NASA/Tim Peake
It is known as the Cupola, an observation and work area that was installed aboard the International Space Station in 2010. In addition to giving the crew ample visibility to support the control of the Station’s robotic arms, it is also the best seat in the house when it comes to viewing Earth, celestial objects and visiting vehicles. Little wonder then why sp many breathtaking pictures have been taken from inside it over the years.
So you can imagine how frustrating it must be for the crew when a tiny artificial object (aka. space debris) collides with the Cupola’s windows and causes it to chip. And thanks to astronaut Tim Peake and a recent photo he chose to share with the world, people here on Earth are able to see just how this looks from the receiving end for the first time.
So, just how do we keep our space stations, ships and astronauts from being riddled with holes from all of the space junk in orbit around Earth?
We revel in the terror grab bag of all the magical ways to get snuffed in space. Almost as much as we celebrate the giant brass backbones of the people who travel there.
We’ve already talked about all the scary ways that astronauts can die in space. My personal recurring “Hail Mary full of grace, please don’t let me die in space” nightmare is orbital debris.
We’re talking about a vast collection of spent rockets, dead satellites, flotsam, jetsam, lagan and derelict. It’s not a short list. NASA figures there are 21,000 bits of junk bigger than 10 cm, 500,000 particles between 1 and 10 cm, and more than 100 million smaller than 1 cm. Sound familiar, humans? This is our high tech, sci fi great Pacific garbage patch.
Sure, a tiny rivet or piece of scrap foil doesn’t sound very dangerous, but consider the fact that astronauts are orbiting the Earth at a velocity of about 28,000 km/h. And the Tang packets, uneaten dehydrated ice cream, and astronaut poops are also traveling at 28,000 km/h. Then think about what happens when they collide. Yikes… or yuck.
Here’s the International Space Station’s solar array. See that tiny hole? Embiggen and clarinosticate! That’s a tiny puncture hole made in the array by a piece of orbital crap.
The whole station is pummeled by tiny pieces of space program junk drawer contents. Back when the Space Shuttle was flying, NASA had to constantly replace their windows because of the damage they were experiencing from the orbital equivalent of Dennis the Menace hurling paint chips, fingernail clippings, and frozen scabs.
That’s just little pieces of paint. What can NASA do to keep Sandra Bullock safe from the larger, more dangerous chunks that could tear the station a new entry hatch?
For starters, NASA and the US Department of Defense are constantly tracking as much of the orbital debris that they can. They know the position of every piece of debris larger than a softball. Which I think, as far as careers go, would be grossly underestimated for its coolness and complexity at a cocktail party.
Artist’s impression of debris in low Earth orbit. Credit: ESA
“What do you do for a living?”
“Me, oh, I’m part of the program which tracks orbital debris to keep astronauts safe.”
“So…you track our space garbage?”
“Uh, actually, never mind, I’m an accountant.”
Furthermore, they’re tracking everything in low Earth orbit – where the astronauts fly – down to a size of 5 cm. That’s 21,000 discrete objects.
NASA then compares the movements of all these objects and compares it to the position of the Space Station. If there’s any risk of a collision, NASA takes preventative measures and moves the Space Station to avoid the debris.
The ISS has thrusters of its own, but it can also use the assistance of spacecraft which are docked to it at the time, such as a Russian Soyuz capsule.
NASA is ready to make these maneuvers at a moment’s notice if necessary, but often they’ll have a few days notice, and give the astronauts time to prepare. Plus, who doesn’t love a close call?
For example, in some alerts, the astronauts have gotten into their Soyuz escape craft, ready to abandon the Station if there’s a catastrophic impact. And if they have even less warning, the astronauts have to just hunker down in some of the Station’s more sturdy regions and wait out the debris flyby.
The Iridium constellation – a robust satellite network (Iridium)
This isn’t speculation and overcautious nannying on NASA’s part. In 2009 an Iridium communications satellite was smashed by a dead Russian Kosmos-2251 military satellite. The collision destroyed both satellites instantly. As icing on this whirling, screaming metallic orbital-terror-cake, it added 2,000 new chunks of debris to the growing collection.
Most material was in a fairly low orbit, and much of it has already been slowed down by the Earth’s atmosphere and burned up.
This wasn’t the first time two star-crossed satellites with a love that could-not-be had a shrapnel fountain suicide pact, and I promise it won’t be the last. Each collision adds to the total amount of debris in orbit, and increases the risk of a run-away cascade of orbital collisions.
We should never underestimate the bravery and commitment of astronauts. They strap themselves to massive explosion tubes and weather the metal squalls of earth orbit in tiny steel life-rafts. So, would you be willing to risk all that debris for a chance to fly in orbit? Tell us in the comments below.
Image of a gecko foot, whose ability to stick on to surfaces inspired NASA's Jet Propulsion Laboratory to develop a possible space debris snagging system. Credit: Wikimedia Commons
We’ve written extensively about the orbital debris problem here on Universe Today. In a nutshell, just about every time we launch something from Earth there are bits and pieces that are left behind. Screws. Paint flecks. Sometimes bigger pieces from rocket stages, or at worst, dysfunctional satellites.
Added to the list of lasers, magnets, robot hands and other ideas to get space junk out of orbit is a new one from NASA — gecko grippers. Yes, lizard hands. The idea is by using techniques from these animal appendages, we might be able to efficiently snag dead satellites or other debris at low cost.
Space debris is all whizzing above us and puts us at risk for devastating crashes that can create a sort of prison of debris for any spacecraft hoping to fly above the atmosphere. We’ve already had to move the shuttle and International Space Station due to threats, and the fear is as more satellites reach space, the problem will get worse.
Here’s what NASA has to say about the idea, which is led by Aaron Parness, a robotics researcher at the Jet Propulsion Laboratory:
The gripping system … was inspired by geckos, lizards that cling to walls with ease. Geckos’ feet have branching arrays of tiny hairs, the smallest of which are hundreds of times thinner than a human hair. This system of hairs can conform to a rough surface without a lot of force. Although researchers cannot make a perfect replica of the gecko foot, they have put “hair” structures on the adhesive pads of the grippers.
The grippers were put through their paces in a simulated microgravity test in August (recently highlighted on NASA’s website). On a plane that flew parabolas with brief “weightless” periods, the grippers managed to grab on to a 20-pound cube and a 250-pound researcher-plus-spacecraft-material-panels combination.
NASA-funded researchers test “gecko grippers” on a simulated-microgravity flight to see how effective they could be for snagging satellites. Here, a researcher has strapped spacecraft-like panels to his body to perform the test. Credit: NASA/YouTube (screenshot)
The key limitation was researchers actually held on to their invention themselves, but eventually they hope to use a robotic leg or arm to achieve the same purpose. Meanwhile, on the ground, the grippers have been used on dozens of spacecraft surfaces in a vacuum and in temperatures simulating what you’d find in orbit.
There’s no guarantee that the system itself will make it to space, as it’s still in the early stages of testing. But in a statement, Parness said he thinks it’s possible that “our system might one day contribute to a solution.” NASA also said these could be used for small satellites to attach to the space station, but development would need to move quickly in that case. The station is only guaranteed to be in use until 2020, with possible extension to 2024.
Simulation of how Space Fence will track orbital space debris. Image courtesy Lockheed Martin
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Several times a year, the International Space Station needs to perform Debris Avoidance Maneuvers to dodge the ever-growing amount of space junk hurtling around in Earth orbit. Additionally, our increased dependence on satellites for communications and navigation is threatened by the risk of potential collisions with space debris. The existing system for finding and tracking objects, the Air Force Space Surveillance System, or VHF Fence, has been in service since the early 1960s, and is sorely out of date. But a prototype system called Space Fence has now been tested in a series of demonstrations, and successfully tracked more and smaller pieces of debris than the current system.
“The current system has the ability to track about 20,000 objects,” Lockheed Martin spokesperson Chip Eschenfelder told Universe Today, “but there millions of objects out there, many of which are not being tracked. Space Fence will find and catalog smaller objects than what are not being tracked now.”
Space Fence will use powerful new ground-based S-band radars to enhance the way the U.S. detects, tracks, measures and catalogs orbiting objects and space debris with improved accuracy, better timeliness and increased surveillance coverage, Lockheed Martin said. In recent tests, the Space Fence prototype proved it could detect more and smaller objects than the current system.
Space debris includes non-operational satellites, and leftover rocket parts from launches. Basically, every time there is a launch, more debris is created. Collisions between the current debris create even more pieces that are smaller and harder to detect. With the debris traveling at lightning-fast orbital speeds, even pieces as small as a paint chip could be deadly to an astronaut on EVA at the space station, or could take out a telecommunications or navigation satellite.
A look at the Space Fence control center. Credit: Lockheed Martin
The developers of Space Fence say the new system will revolutionize what’s called ‘space situational awareness,’ which characterizes the space environment and how it will affect activities in space.
“Space Fence will detect, track and catalog over 200,000 orbiting objects and help transform space situational awareness from being reactive to predictive,” said Steve Bruce, vice president of the Space Fence program. “The Air Force will have more time to anticipate events potentially impacting space assets and missions.
The current system has tracking locations in the US only and has a huge ‘blind spot’ by not supplying information about debris in the southern hemisphere. But Space Fence will provide global coverage from three ground-based radar located at strategic sites around the world.
On February 29, 2012, the Air Force granted its final approval of Lockheed Martin’s preliminary design, and they expect the new system’s initial operational capability to be sometime in 2017.
“The successful detection and tracking of resident space objects are important steps in demonstrating technology maturity, cost certainty and low program risk,” said Bruce in a statement. “Our final system design incorporates a scalable, solid-state S-band radar, with a higher wavelength frequency capable of detecting much smaller objects than the Air Force’s current system.”
