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 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.
To break the numbers down, according to ESOC, about 5250 launches have taken place since the beginning of the space age, which officially kicked off on October 4th, 1957, with the launch of the the Soviet Sputnik 1 satellite. Of the many missions that have been launched since then, some 23,000 are still in orbit, while only 1200 are still operational.
Sources of space debris include explosions of rocket bodies. Credit: ESA
However, this accounts of only 6% of all the actual objects in orbit. Another 38% can be attributed to decommissioned satellites, spent upper stages and mission-related objects (launch adaptors, lens covers, etc.). All told, an estimated 94% of objects in orbit qualify as being "space debris" - a term used to describe objects which no longer serve any useful purpose.
About 64% of these objects are fragments from the many breakups, explosions and collisions of satellites or rocket bodies that have taken place over the past decades. In addition, there is evidence of a much larger population of debris that cannot be tracked operationally. That's where the ESA's latest numbers once again come into play.
According to various statistical models, there is an estimated 166 million objects in orbit that range in size from 1 mm to 1 cm in diameter. There is also another 750,000 objects that range from being 1cm to 10 cm in diameter, and about 29,000 objects that exceed 10 cm in diameter. The ESA and other space agencies around the world are responsible for tracking about 42,000 of the larger ones.
All told, the total mass of all the objects orbiting the Earth is estimated at 7500 metric tons (~8267 US tons). And between all this debris, a little over 290 break-ups, explosions and collisions events have taken place, resulting in the fragmentation of objects and the creation of many smaller pieces of debris. Each and every one of these is considered a serious threat due to the relative orbital velocities they have.
The chip in the ISS' Cupola window, photographed by astronaut Tim Peake. Credit: ESA/NASA/Tim Peake
Essentially, orbital debris can reach speeds of up to 56,000 km/h due to the Earth's rotation. At this speed, even a centimeter-sized piece of debris can seriously damage or disable an operational spacecraft. Meanwhile, a collision with an object that is larger than 10 cm will lead to catastrophic break-ups, releasing more hazardous debris clouds that can cause further catastrophic collisions - a phenomena known as "Kessler Syndrome".
Left unchecked, it is acknowledged that the problem will become exponentially worse. Little wonder then why the ESA and other space agencies are talking about implementing "space debris mitigation measures". Such measures, which include reducing mass in high-density regions and designing craft with safe re-entry technologies, could curtail the growth rate of space debris populations.
This conference will be taking place from April 18th to 21st, 2017, at the European Space Operations Center in Darmstadt, Germany. As the largest gathering of its kind, this four-day conference will see internationally renowned scientists, engineers, operators, lawyers and policy makers from around the world coming together to discuss different aspects of space debris research.
ESA graphic titled "Why Space Debris Mitigation is needed". Click to enlarge and animate. Credit: ESA
This will include measurement techniques, environment modelling theories, risk analysis techniques, protection designs, mitigation and remediation concepts, and policy & legal issues. In addition to providing a forum for presenting and discussing the latest results, this conference also is chance for experts to define future directions for research.
The space lanes need to be cleared if we hope to commercialize and exploit Low Earth Orbit (LEO) in the coming years. And the good folks who conduct research aboard the ISS and China's Tianglong-1 space station would surely appreciate it.
Republicans released a modified health care bill on Monday, in an attempt to shore up support among both conservatives and moderates for their legislation to replace the Affordable Care Act. Under the modified version, states would be allowed to require able-bodied Medicaid recipients without dependents to work beginning in October. Those changes were made to draw support from conservative members disappointed that the original bill didn't go far enough to undo the Affordable Care Act, popularly known as Obamacare. The House will vote on the bill on Thursday.
The SpaceX Dragon CRS-10 spacecraft is pictured seconds before splashing down in the Pacific Ocean on Mar. 19, 2017 after departing the International Space Station (ISS). Credit: SpaceX
KENNEDY SPACE CENTER, FL - SpaceX's tenth contracted resupply mission to the International Space Station came to a safe conclusion with a splashdown in the Pacific Ocean Sunday and successfully returned a treasure trove of more than two tons of precious science experiments and research samples from the space station.
Researchers on Earth are eagerly awaiting the science data and samples in order to carry out high powered laboratory analysis that will eventually yield the fruits of the hard won labor - years in the making.
The Dragon CRS-10 cargo freighter departed the International Space Station (ISS) Sunday morning after Expedition 50 astronauts Thomas Pesquet of ESA (European Space Agency) and Shane Kimbrough of NASA released the spacecraft from the grip of the station's 57.7-foot-long(17.6-meter) Canadian-built Canadarm2 robotic arm as planned at 5:11 a.m. EDT, March 19.
After carefully maneuvering away from the orbiting outpost and six person international crew at an altitude of appox. 250 miles (400 km), Dragon eased away to a safe distance.
SpaceX's Dragon CRS-10 cargo vehicle is attached to the International Space Station on Feb 23, 2017 after early morning capture by astronauts Shane Kimbrough and Thomas Pesquet using the robotic arm and subsequent berthing at Earth facing port on the Harmony module. It will stay for a month. Credit: NASA
The vessel then fired its braking thrusters a few hours later to initiate the reentry burn that would set the craft on course for a fiery plummet through the Earth's atmosphere.
Some five and a half hours later the spaceship carried out a parachute assisted splashdown in the Pacific Ocean at 10:46 a.m. EDT, about 200 miles southwest of Long Beach, California.
The highest priority research and technology cargo will be removed from Dragon immediately and returned to NASA.
SpaceX CRS-10 Dragon supply ship launched on Feb. 19, 2017 from NASA's Kennedy Space Center in Florida successfully arrives at the International Space Station on Feb. 23, 2017 for capture and berthing at station port on the Harmony module. Credit: NASA
The rest will travel back to port and be prepared for a return trip to SpaceX's test facility in McGregor, Texas, where the remaining scientific samples, research experiments and technology gear and hardware will be unloaded for NASA.
Dragon had spent nearly a month berthed at the Earth-facing port on the station's Harmony module, since arriving on Feb 23.
Dragon begun its space voyage after it was launched from the Kennedy Space Center (KSC) on Sunday, Feb. 19 on the first Falcon 9 rocket ever to blast off from historic launch pad 39A in a blaze of glory - as I reported here.
Historic maiden blastoff of SpaceX Falcon 9 rocket from Launch Complex 39A at the Kennedy Space Center) at 9:38 a.m. EDT on Feb 19, 2017, on Dragon CRS-10 resupply mission to the International Space Station (ISS) for NASA. Credit: Ken Kremer/kenkremer.com
At liftoff, the Dragon CRS-10 space freighter was carrying more than 5500 pounds of equipment, gear, food, crew supplies, hardware and NASA's Stratospheric Aerosol Gas Experiment III (SAGE III) ozone mapping science payload to the low Earth orbiting station in support of the Expedition 50 and 51 crew members.
After a four day chase, Dragon was captured and attached to the station using the Canadian arm on Feb 23 by the same two astronauts who released it on Sunday.
The research supplies and equipment brought up by Dragon will support over 250 scientific investigations to advance knowledge about the medical, psychological and biomedical challenges astronauts face during long-duration spaceflight.
SAGE III will measure stratospheric ozone, aerosols, and other trace gases by locking onto the sun or moon and scanning a thin profile of the atmosphere. It is one of NASA's longest running earth science programs. The LIS lightning mapper will measure the amount, rate and energy of lightning as it strikes around the world from the altitude of the ISS as it orbits Earth. Its data will complement that from the recently orbited GLM lighting mapper lofted to geosynchronous aboard the NASA/NOAA GOES-R spacecraft instrument.
NASA's RAVEN experiment will test autonomous docking technologies for spacecraft.
SAGE III and RAVEN were stowed in the Dragon's unpressurized truck. Astronauts plucked them out of the trunk using the robotic arm and attached them to specified locations on the stations exterior to carry out their objectives.
For the return trip to Earth, the astronaut crew loaded Dragon with more than 5,400 pounds of NASA cargo, and science and technology demonstration samples gathered and collected by the stations crewmembers.
"A variety of technological and biological studies are returning in Dragon. The Microgravity Expanded Stem Cells investigation had crew members observe cell growth and other characteristics in microgravity," said NASA.
"This information will provide insight into how human cancers start and spread, which aids in the development of prevention and treatment plans. Results from this investigation could lead to the treatment of disease and injury in space, as well as provide a way to improve stem cell production for human therapy on Earth."
"Samples from the Tissue Regeneration-Bone Defect study, a U.S. National Laboratory investigation sponsored by the Center for the Advancement of Science in Space (CASIS) and the U.S. Army Medical Research and Materiel Command, studied what prevents vertebrates such as rodents and humans from re-growing lost bone and tissue, and how microgravity conditions affect the process. Results will provide a new understanding of the biological reasons behind a human's inability to grow a lost limb at the wound site, and could lead to new treatment options for the more than 30 percent of the patient population who do not respond to current options for chronic non-healing wounds."
Dragon departed in order to make way for the arrival of the next cargo ship.
The 'SS John Glenn' Cygnus cargo freighter built by Orbital Sciences is due to lift off no earlier than March 27 on a United Launch Alliance (ULA) Atlas V rocket from Cape Canaveral Air Force Station.
Watch for Ken's onsite launch and mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news.