OrbitalHub

Credits: Space Concordia Team

The Canadian Satellite Design Competition (CSDC) is a Canada-wide competition for teams of university students (undergraduate and graduate) to design and build low-cost satellite. The CSDC plans to subject the satellites in competition to full space qualification testing, and to launch the winning satellite into orbit to conduct science research. The CSDC is modeled after existing university engineering competitions, such as those sponsored by the National Aeronautics and Space Administration (NASA) or the Society for Automotive Engineers (SAE).

The winning teammates are members of Space Concordia, a student-run astronautical engineering association based in the Faculty of Engineering and Computer Science at the Concordia University in Montreal. The selection process was conducted by industry experts at the David Florida Laboratory of the Canadian Space Agency in Ottawa, a highly secured facility where commercial and research satellites from the United States and Europe are routinely tested. From twelve teams that initially entered the competition, Space Concordia Team was among only three to go for final testing. Alex Potapov, Mechanical Team Lead, answered a few questions about the Space Concordia cubesat mission.

Q: What is the scientific payload for the mission you are designing?
A: Our mission is to study the south Atlantic anomaly, more on that here. We plan on doing this by detecting high energy particles present in the region. Our spacecraft is equipped with a Geiger Counter operating in its proportional mode. This will allow us to determine not only the amount of radiation but also the type of particle present.

Q: What hardware do you intend to use? Off-the-shelf boards and software or are you developing your own?
A: Most of our components are of the shelf with the exception of several printed circuit boards. One of the more impressive and less accessible pieces of hardware is the Xiphos Q6, which is a sophisticated FPGA that will be used as the central computer of our satellite. The software is developed internally, and it is based on the Linux operating system.

Q: How do you intend to communicate with your satellite from the ground? UHF, Iridium modem, etc.?
A: The spacecraft will communicate with a ground station located near Montreal by means of an antenna that is capable of transmitting and receiving at UHF and VHF armature frequency bands. At this orbit we will have a communication window of about 10-11 min per pass. The communication system was entirely developed by Tiago Leao, PhD Candidate at Concordia University.

Q: How do you generate and store power onboard the satellite? Batteries, solar panels? Do you intend to use deployable solar panels?
A: The satellite is equipped with four solar arrays made of 6 ultra high efficiency solar cells each, these cells charge 4 lithium ion batteries. The solar cells are mounted to the body panels of the spacecraft and are not deployable. The entire power system was designed and developed by Ty Boer, an electrical engineering student at Concordia University.

Q: Does the attitude determination and control system rely solely on reaction wheels? How do you intend to unload them? Magnetorquers, cold gas thrusters, or have you developed a novel technique?
A: Our approach to ACS does not require any of the above, the philosophy behind the cubesat was to keep it as simple as possible and still perform its mission, therefore a passive ACS system was selected. The system contains of permanent magnets and hysteresis rods, this will allow us to remain stable through communication window. We also have sun sensors for telemetry data.

Q: Do you plan to have any orbit control systems onboard? What is the orbital profile of the mission?
A: No, there is no active orbit control on-board. The flight software has a look up table that it uses to determine the spacecraft position, this table is updated through TLE data. We then use this position to execute certain commands such as power on the transmitter to establish communication.

Q: How do you plan to control the temperature onboard the satellite?
A: The satellite has a passive cooling system, and active heaters that keep critical components such as the batteries within operating range. Cooling is controlled by careful design of conductive elements and optical surfaces.

Q: Who are the members registered with your team? What areas of expertise do they represent?
A: The Space Concordia core team members are: Nick Sweet (Project Manager), Alex Potapov (Mechanical team lead), Tiago Leao (Communication systems lead), Ty Boer (Power system lead), Shawn Stoute (Command and data handling lead), Alex Teodor (Software system lead), Gregory Gibson (ACS and Payload lead), Ivan Ivanov (Manufacturing Lead and Mechanical Design), Mehdi Sabzalian (Procurement lead, Structural analysis, Administration), Robert Jakubowicz (Senior Software Developer), Stefanos Dermenakis (Mechanical design, Thermal analysis), Andrei Jones (Mechanical Harness Design). You can find more about the contributors to the project on our about page.

To find out more about the Space Concordia Team, you can visit the Space Concordia web page. More information about the Canadian Satellite Design Competition can be found on the CSDC web page.

Credits: Clyde Space

The second Canadian Satellite Design Competition (CSDC) team that answered our invitation to a Q&A is the team from Dalhousie University. Colin O’Flynn, graduate student at Dalhousie University and CTO of the CSDC team, answered our questions.

Q: What hardware do you intend to use? Off-the-shelf boards and software or are you developing your own?
A: We are aiming to use COTS boards and software as much as possible, especially during development. Eventually we will be forced to design and build custom hardware, since there is a very specific form-factor which many COTS boards won’t fit inside. Weight is also a huge issue for us – since many COTS boards contain lots of features we might not need (e.g.: LCD display, Ethernet connector), we can shave some weight by spinning our own board and not wasting space or weight with those features.

Ideally though we’ll just adapt the COTS board design to our satellite, meaning we can use a tested design with minimal work. Not Invented Here (NIH) syndrome is dangerous to engineering projects, so while our current research does show we can’t find the correct form factor, we’ll always be checking the market for new products that might let us avoid needless designs and builds.

Q: How do you intend to communicate with your satellite from the ground? UHF, Iridium modem, etc.?
A: Again our satellite has slightly different objectives from a normal commercial satellite, which are primarily concerned with issues such as maximizing bandwidth or minimizing lag, since that gives the best return on investments.

In our project we also want to provide something with a wide scientific and public appeal. To that end we plan on using amateur radio frequencies – this means people around the world can track our satellite. Often amateur radio operators are on the lookout for interesting projects which introduce young students to radio communications. Letting students receiver data from a real satellite overhead does a lot to promote both amateur radio and space, which just maybe will help inspire the next generation of engineers.

Whether this will be in the S-Band or just UHF hasn’t been finalized yet, although there is potential to actually have a beacon running in the more common UHF, and our more bandwidth-intensive comms (e.g.: for downloading payload data) in S-Band. The actual coding technique will use more recent codes (e.g.: turbo or LDPC). Again since this is supposed to be a more ‘innovative’ approach to space, we are working with some of the respected professors and students in our department to get recent advances in both coding and antenna design on our spacecraft.

Q: How do you generate and store power onboard the satellite? Batteries, solar panels? Do you intend to use deployable solar panels?
A: The solar panels will not be deployable, but fixed on the outside surface, with batteries storing the charge. This area will use more mature technology. The power system is so critical, and since testing the components such as panels or batteries for the required environmental conditions is beyond our capabilities, we don’t want to rely on experimental designs.

Q: Does the attitude determination and control system rely solely on reaction wheels? How do you intend to unload them? Magnetorquers, cold gas thrusters, or have you developed a novel technique?
A: The satellite is very small; many Cubesats only use magnetorquers without reaction wheels. This limits what and where you can correct obviously, so we are still exploring more interesting techniques. We have “penciled in” reaction wheels and magnetorquers, but this could drastically change.

The attitude determination is also planned to be pretty standard. Due to the small size of sensors on the market, we actually plan on outfitting our satellite with a wide range of sensors beyond what is required for attitude determination. We plan on adding a three-axis magnetometer, gyro, and accelerometer, along with GPS receiver. The idea is to provide enough data for postprocessing on Earth for testing new algorithms, experiments, etc.

Q: Do you plan to have any orbit control systems onboard? What is the orbital profile of the mission?
A: Nothing planned yet; the orbit we are given is defined as:

The design orbit for the mission has the following parameters (TBC):

• Semi-major Axis: 7078 ± 100 km (600km to 800km altitude)

• Eccentricity: < 0.01
• Inclination: sun-synchronous for the resulting altitude

Launch details won’t be confirmed for some time, so some of this is mostly chance depending what we end up riding along with.

The only possible orbit control system we are investigating would be for deorbiting the satellite at the end of its life. Space is a shared resource, and we want to make sure we aren’t needlessly polluting it with our satellite. If it naturally will deorbit in a reasonable time this won’t be necessary, but it’s something we want to be sure of.

Q: How do you plan to control the temperature onboard the satellite?
A: Currently something we are investigating. Preliminary calculations show we can do this passively to keep things within acceptable limits. Other Cubesats have done this in practice too.

We are trying to use automotive grade parts when possible, which gives us a better temperature range to work with. Understandably this isn’t possible for everything; the solar cells and battery are one obvious example.

Q: Who are the members registered with your team? What areas of expertise do they represent?
A: It’s a huge range of skills we have, including over a quarter that aren’t engineers or scientists. Our team is pushing outreach in the community, so for example running programs to introduce kids to space exploration, and the idea that it’s something they could become involved in themselves. Other sections of the team such as marketing, management, and finances are critical to our success, but have nothing to do with the core technical designs.

The technical team has about ten core members. The number of people working on the project though will be higher: we are defining senior year projects, which students will be able to get credit hours for. Time is always a problem in student run projects, so we are trying to make sure people get credit for all this work. Or as I like to point out: once they agree to help, they have to help, because otherwise they will fail the senior year project! It’s one way of retaining “volunteers”.

Credits: UMSATS Team

The Canadian Satellite Design Competition (CSDC) is a Canada-wide competition for teams of university students (undergraduate and graduate) to design and build low-cost satellite. The CSDC plans to subject the satellites in competition to full space qualification testing, and to launch the winning satellite into orbit to conduct science research. The CSDC is modeled after existing university engineering competitions, such as those sponsored by the National Aeronautics and Space Administration (NASA) or the Society for Automotive Engineers (SAE).

CSDC has other declared objectives as well:

• to promote education, excellence, research, development, and future capability in space activities in Canada.

• to foster innovation in satellite technologies and inexpensive access to space.

• to seek new applications of technologies and space missions for the betterment of Earth.

One of the teams in competition is the University of Manitoba Team, UMSATS. Dario Schor, UMSATS Project Lead, answered a few questions about the T-Sat (triple pico-satellite) designed by the University of Manitoba Team.

Q: What is the scientific payload for the mission you are designing?
A: The University of Manitoba mission carries two scientific payloads: a Tardigrade Experiment and a Solar Spectroscopy Experiment.

The Tardigrade Experiment aims to test the survivability of Tardigrades (a class of extremophile organisms also known as water bears) in space. This will be accomplished by sending a colony of tardigrades in a cryptobiosis state, exposing them to the harsh space environment, reviving them in orbit, and monitoring their behavior by taking bursts of images at predetermined times throughout the first 30-40 days of the mission. The novelty of the experiment is in the on-board revival of the organisms that has not been done in any satellite, let alone a nanosatellite that is only 10x10x30cm.

The Solar Spectroscopy Experiment measures the intensity of light emitted from the Sun over the ultraviolet to near-infrared regime (350nm to 1100 nm) to add and compare the results to theoretical models and data collected by other missions. This type of experiment has been performed on a number of missions with larger spacecrafts, thus demonstrating comparable results on a smaller and cheaper platform can open the door for many other small research groups to conduct similar experiments to collect and analyze their own data.

Q: What hardware do you intend to use? Off-the-shelf boards and software or are you developing your own?
A: The spacecraft uses off-the-shelf components in custom designs for all subsystem boards. The extra efforts and risks from custom designs, manufacturing, and testing are offset by the experience gained by the students on the team. Some examples of the components used include:

• The Command & Data Handling (CDH) subsystem uses the TI MSP430 microprocessor interfaces to a watchdog timer, real-time clock, and memory modules for their operations.

• The Communications (COM) subsystem uses stripped down version of a commercial-off-the-shelf handheld from Yaesu that operates on amateur frequencies. Digital packets are created and encoded using a custom Terminal Node Controller based on the TI MSP430 microprocessor.

• The Power (PWR) subsystem uses fixed solar panels, an off-the-shelf battery, and a custom protection and distribution system to provide power to the spacecraft.

• The Structure (STR) is being built in-house out of Aluminum 6061. The custom design was required to support the two payload’s requirements for heat, volume, and position within the spacecraft.

• The Thermal (THM) subsystem relies primarily on insulation for its components and uses an off-the-shelf heater to maintain the Tardigrade experiment from freezing.

• The Attitude Determination and Control (ADC) subsystem uses off-the-shelf sensors, such as the Honeywell HMC2003 magnetometer, with customized designs for magnetic torque rods to control the orientation of the spacecraft.

Q: How do you intend to communicate with your satellite from the ground? UHF, Iridium modem, etc.?
A: The spacecraft is designed to communicate with amateur radio stations conforming to the GENSO standard (genso.org). That means using the 2m band (144-148MHz) for uplink commands, and the 70cm (435-438MHz) for downlink telemetry and science, similar to many AMSAT satellites such as AO-51, HO-68, and FO-29. The spacecraft configurations with the two antennas is shown in Fig. 3. All packets are encoded using the AX.25 protocol that is compatible with most amateur ground stations, such as the University of Manitoba Satellite Ground Station.

Q: How do you generate and store power onboard the satellite? Batteries, solar panels? Do you intend to use deployable solar panels?
A: The spacecraft is designed to operate with a minimum of 4 Watts. Power is generated using fixed solar panels on all faces of the spacecraft and storing it in an on-board battery to power the spacecraft during eclipses. The fixed panels provide sufficient power for the mission without the added risks from deployable panels.

Q: Does the attitude determination and control system rely solely on reaction wheels? How do you intend to unload them? Magnetorquers, cold gas thrusters, or have you developed a novel technique?
A: The Attitude Determination and Control (ADC) subsystem uses a magnetometer and Sun sensors to determine the orientation of the spacecraft. Custom built magnetic torquers are used to control the orientation. The torquers are implemented in multilayered flat coils enabling easy integration of the torque rods with the rest of the system.

Q: Do you plan to have any orbit control systems onboard? What is the orbital profile of the mission?
A: There is no orbit control system onboard. This would be very difficult to achieve in a small 10x10x30 cm spacecraft with a maximum mass of 4kg as thrusters and fuel would require a large portion of the mass and volume leaving little room for scientific payloads.

The current goal is for a sun-synchronous orbit with an inclination of 98 degrees, eccentricity ~0, and altitude of approx. 600-800km. A sample profile for a 24 hr period for the mission is shown in Fig. 4. The field of view from the University of Manitoba Satellite Ground Station (operational since 2008) shows the contact points over the 24 hr period.

Q: How do you plan to control the temperature onboard the satellite?
A: The thermal control is mostly passive except for a heater attached to the Tardigrade payload to ensure the water and nutrients for the water bears do not freeze. Analysis of the temperature profiles revealed that the remaining components can stay within their allowed operating temperatures using small layers of insulation.

Q: Who are the members registered with your team? What areas of expertise do they represent?
A: The University of Manitoba team has over 100 registered students from Engineering, Science, Business, Architecture, Art, and Graduate Studies that contributed to the project since October 2010 with the largest group coming from the Department of Electrical and Computer Engineering. This includes students from first year all the way through Ph.D. programs, thus providing a strong core for this mission as well as laying the foundation for future missions at the University of Manitoba. At the moment, there is a core group of 35 students that are working on various aspects of the project.

The students are supported by a team of over 50 advisors from academia, industry (specifically aerospace from Magellan Bristol Aerospace), government, military, amateur radio community, and others. The advisors attend regular review meetings for the full project and some of the subsystems to provide feedback on the design.

To find out more about the UMSATS, you can visit the UMSTAS web page, or contact Dario Schor. More information about the Canadian Satellite Design Competition can be found on the CSDC web page.

Credits: NASA

The 140 companies and organizations listed in the Canadian Space Directory generated $3.44 billion CDN in revenue and employed over 8000 Canadians in 2010, according to the 2010 State of the Canadian Space Sector Report. These firms support the technologies required for weather forecasting, remote sensing, GPS systems, satellite and cable television, remote phone communication systems and even our Canadian astronautcorps.

They also provide equipment and technical support to scientists performing experiments and developing new technologies related to astronomy, Earth sciences, medicine and many other fields at over a dozen university faculties located throughout the country plus facilitate communications and space situational awareness for our Canadian military in the far North for Arctic sovereignty and on missions throughout the world. Taken together, these companies, the educational facilities developing new innovations, our military, plus the government and industry organizations and the facilities they utilize represent our critical Canadian space infrastructure.

But this infrastructure is in a state of crisis. What must we do to protect, support and grow this disparate group of private and public organizations, capabilities and supporting infrastructure? Join us to find out at this full day discussion of Canada’s future in space.

The Canadian Space Commerce Association 2012 Conference is featuring:

• Joan Harvey – Head of Research &Analysis, Policy and External Relations, Canadian Space Agency (CSA)
• Maryse Harvey and/or Jim Quick – VPand CEO, respectively, Aerospace IndustriesAssociation of Canada
• Dr. Christian Feichtinger – Executive Director, International Astronautical Federation
• Alex Saltmann – Executive Director, Commercial Space Flight Federation
• Robert Godwin – Director, Canadian Air and Space Museum, and Owner, Apogee Books
• Dr. Arsen Hajian – Arjae Spectral Enterprises
• Ron Holdway – President, Canadian Aeronautics and Space Institute, and VP of Government Relations, Com Dev International
• ScottLarson – President, Urthe Cast
• Dr. Gordon Osinski – NSERC/MDA/CSA Industrial Research Chair in Planetary Geology, University of Western Ontario
• Larry Reeves – Director, Canadian Satellite and Design Challenge (CSDC)
• Nobina Robinson – CEO, Polytechnics Canada, and member of the Review of Federal Support to Research and Development (the Jenkins Panel)
• Kevin Shortt – President, Canadian Space Society
• Cliff Sosnow – Chair of the International Trade and Investment Group, Blake, Cassels & Graydon LLP
• Michael Woods –Partner, Heenan Blaikie Law Firm

Date & Time: Wednesday, March 28th, 2012, 8:30 AM – 5:30 PM, with a Networking & Social Eventat 7:00 PM

Location: National Arts Centre, Fountain Room, 53 Elgin Street, Ottawa, Ontario, K1P 5W1, Canada

CSCA is looking for three speakers on the topic of their start-up commercial space venture modeled on the format of the O’Reilly’s Ignite Talks under the motto “Enlighten Us, But Make It Quick!”. Anyone who is interested should submit an abstract with contact information and a 5-minute presentation for consideration, to Marc Boucher.

CSCA is looking for two volunteers for the CSCA 2012 Conference. If you are interested in this opportunity, please email Farnaz Ghadaki.

To find out more about this event, please visit the Canadian Space CommerceAssociation website. For registration, please visit: http://2012canadianspacecommerceassociation.eventbrite.com/

Credits: MDA

MDA (MacDonald, Dettwiler and Associates Ltd.) is a Canadian company that was incorporated in 1969 by two British Columbia entrepreneurs, John MacDonald and Werner Dettwiler. The company offers a broad spectrum of services. Currently, MDA is developing a Space Infrastructure Servicing (SIS) spacecraft that would operate as a refueling depot for communication satellites in geosynchronous orbit.

Geostationary communication satellites have to perform regular orbital stationkeeping maneuvers, which need delta-v of approximately 50 m/s/year (this translates into fuel consumption). As a result, the lifespan of a satellite is proportional to the amount of fuel it carries onboard, even if most satellites are capable of operating beyond this lifespan. MDA’s SIS system would extend the operational lifespan of these satellites and save satellite operators a lot of money (refueling a satellite would save the operators the cost of building and launching a new satellite).

A typical SIS mission profile not only includes satellite refueling, but also cleaning orbital slots by pushing dead satellites into graveyard orbits. This would also be a money saver because orbital slots are quite expensive.

However, there are challenges. The satellites currently operating are not designed to be serviced/refueled while on orbit (the Hubble Space Telescope is a notable exception). And this will make the refueling maneuver quite complicated… the servicing satellite has to remove a part of the thermal protection blanket of the target spacecraft before connecting to an internal fuel line.

In a March 15, 2011, press release, MDA announced that Intelsat S.A. entered into an agreement with MDA for the servicing of Intelsat’s operational satellites. On-orbit servicing is to be performed by a space-based service vehicle provided by MDA. From the press release:

“The SIS vehicle is expected to be the first of its kind, utilizing a sophisticated robotics and docking system. This system will be based on work that MDA has previously performed for NASA, the Canadian Space Agency and various Department of Defense agencies. The SIS vehicle’s robotic arm will not only be used in refueling, but could also be used to perform critical maintenance and repair tasks, such as releasing jammed deployable arrays and stabilizing or towing smaller space objects or debris. Intelsat, the world’s largest operator of commercial satellites in the geosynchronous arc, is expected to provide flight operations support for the SIS vehicle for the life of the mission.”

The services to be provided by MDA to Intelsat are estimated at more than US$280 million. In the June 17, 2011, press release, MDA also announced that it is extending by three months the requirements definition phase of its SIS initiative.

Needless to say, on-orbit servicing will be a very lucrative endeavor. It also has a strategic importance. Very expensive LEO observation satellites used by the military would benefit from such on-orbit services. Also, NASA is under a tremendous budget pressure. And this can be an answer to the question why NASA would move forward with its own on-orbit servicing initiative.

NASA will demonstrate in-orbit satellite refueling at the International Space Station. MDA-built Dextre, equipped with special tools, will cut through a satellite exterior shell and pump fuel into a mock satellite.

The first thing that comes to mind is that a NASA competition may put the MDA SIS system at risk. Does anyone remember the Avro Canada CF-105 Arrow?

Credits: Ronald C. Wittmann

There are numerous examples of successful implementation of mitigation measures, but also some not so successful, and even failures. There are two cases that I will mention, one from each camp.

Cosmos 954 was a Soviet Radar Ocean Reconnaissance Satellite (RORSAT) powered by an onboard nuclear reactor. At the time, the Russian designers were not able to find an alternative for the power system due to the power requirements of the payload carried by the spacecraft, which was a powerful radar. A post-mission mitigation method that involved parking the nuclear reactor on a higher orbit (with an estimated lifetime of hundreds of years) was adopted.

It seems that not enough effort was put into designing a reliable solution for the post-mission disposal method of the nuclear reactor. Besides the inherent low reliability associated with hardware in developmental phases, the quality assurance practices at that time were most likely affected by the conditions of the Cold War. In both camps, the concerns regarding the environment were ignored in favor of the military and political goals.

In 1978, COSMOS 954 failed to separate its nuclear reactor core and boost it into the post-mission parking orbit as planned. The reactor remained onboard the satellite and eventually re-entered into the Earth atmosphere and crashed near the Great Slave Lake in Canada’s Northwest Territories. The radioactive fuel was spread over a 124,000 km2 area. The recovery teams retrieved 12 large pieces of the reactor, which comprised only 1% of the reactor fuel. All of these pieces displayed lethal levels of radioactivity.

To highlight how dangerous and how serious the use of nuclear power sources for space mission is, consider these figures: at present, there are 32 defunct nuclear reactors in orbit around the Earth. There are also 13 reactor fuel cores and at least 8 radio-thermal generators (RTGs). The total mass of RTG nuclear fuel in orbit is in the order of 150 kg. The total mass of Uranium-235 reactor fuel in orbit is in the order of 1,000 kg.

RADARSAT-1 is an Earth observation satellite developed in Canada. Equipped with a powerful synthetic aperture radar (SAR) instrument, RADARSAT-1 monitors environmental changes and the planet’s natural resources. Well beyond the planned five-year lifetime, the satellite continues to provide images of the Earth for both scientific and commercial applications.

Following the guidelines of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) document entitled Guidelines for Space Debris Mitigation, and implementing mitigation measures required for the space hardware manufacturers in Canada, the Canadian Space Agency has prepared post-mission disposal plans for its remote sensing satellite RADARSAT-1. As a prerequisite to the end of mission procedures, the energy stored in the propellant tanks, the wheels, and the batteries of the satellite will be removed, as suggested in the COPUOS guidelines. Also, the remaining fuel will be used to lower the orbit in addition to orienting the satellite so that drag is maximized. These measures will aim to reduce the orbit life span of the satellite to the lowest possible.

Simulations performed using NASA’s long-term debris environment evolutionary model (LEO-to-GEO Environment Debris model or LEGEND) or ESA’s debris environment long-term analysis tool (DELTA) have shown that even if new launches are not conducted, the existing population of orbital debris will continue to increase. This increase in number is caused by collisions between the objects already orbiting the Earth at the present time. Following the Iridium/Cosmos collision in 2009, the U.S. Air Force has issued hundreds of notifications to Russia and China regarding potential crashes between their satellites and other objects in orbit.

Even if we are contemplating grim future developments like the one mentioned above, international initiatives do not seem to gain enough momentum. NASA (National Aeronautics and Space Administration) and DARPA (Defense Advanced Research Projects Agency) were the sponsors of the first International Conference on Orbital Debris Removal, which was held in Chantilly, Virginia, December 8-10, 2009. The conclusions of the conference included the observation that:

“No evident consensus or conclusions were reached at the conference. Removing existing, non-cooperative objects from Earth orbit is an extremely difficult and likely expensive task. Although some of the techniques for removal discussed at the Conference have the potential of being developed into technically feasible systems, each concept seems to currently suffer from either a lack of development and testing or economic viability.”