On June 25th, 2019, The Planetary Society‘s cubesat spacecraft known as LightSail 2 lifted off from the NASA Kennedy Space Center in Florida aboard a Falcon Heavy rocket. This was the second solar sail launched the Society, the first (LightSail 1) having been sent into space in 2015. Like its predecessor, the purpose of this spacecraft is to demonstrate the technology that would allow for solar sails operating within Low Earth Orbit (LEO).
Since reaching orbit, the LightSail 2 has been indicated that it is in good working order, as indicated by the Mission Control Dashboard recently introduced by The Planetary Society. In addition to establishing two-way communications with mission controllers and passing a battery of checkouts, the spacecraft also took its first pictures of Earth (and some selfies for good measure).
Weather tracking is difficult work, and has historically relied on satellites that are large and cost millions of dollars to launch into space. And with the threat of climate change making things like tropical storms, tornadoes and other weather events more violent around the world today, people are increasingly reliant on early warnings and real-time monitoring.
However, NASA is looking to change that by deploying a new breed of weather satellite that takes advantage of recent advances in miniaturization. This class of satellite is known as the RainCube (Radar in CubeSat), which uses experimental technology to see storms by detecting rain and snow using very small and sophisticated instruments.
In 1990, the Voyager 1spaceprobe took a picture of Earth when it was about 6.4 billion km (4 billion mi) away. In this image, known as the “pale blue dot“, Earth and the Moon appeared as mere points of light because of the sheer distance involved. Nevertheless, it remains an iconic photo that not only showed our world from space, but also set long-distance record.
As it turns out, NASA set another long-distance record for CubeSats last week (on May. 8th, 2018) when a pair of small satellites called Mars Cube One (MarCO) reached a distance of 1 million km (621,371 mi) from Earth. On the following day, one of the CubeSats (MarCO-B, aka. “Wall-E”) used its fisheye camera to take its own “pale blue dot” photo of the Earth-Moon system.
The two CubeSats were launched on May 5th along with the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which is currently on its way to Mars to explore the planet’s interior structure. As the first CubeSats to fly to deep pace, the purpose of the MarCO mission is to demonstrate if CubeSats are capable of acting as a relay with long-distance spacecraft.
To this end, the probes will be responsible for monitoring InSight as it makes its landing on Mars in late November, 2018. The photo of Earth and the Moon was taken as part of the process used by the engineering team to confirm that the spacecraft’s high-gain antenna unfolded properly. As Andy Klesh, MarCO’s chief engineer at NASA’s Jet Propulsion Laboratory, indicated in a recent NASA press release:
“Consider it our homage to Voyager. CubeSats have never gone this far into space before, so it’s a big milestone. Both our CubeSats are healthy and functioning properly. We’re looking forward to seeing them travel even farther.”
This technology demonstration, and the long-distance record recently set by MarCO satellites, provides a good indication of just how far CubeSats have come in the past few years. Originally, CubeSats were developed to teach university students about satellites, but have since become a major commercial technology. In addition to providing vast amounts of data, they have proven to be a cost-effective alternative to larger, multi-million dollar satellites.
The MarCO CubeSats will be there when the InSight lander accomplishes the most difficult part of its mission, which is entering Mars’ extremely thin atmosphere (which makes landings extremely challenging). As the lander travels to Mars, MarCO-A and B will travel along behind it and (should they make it all the way to Mars) radio back data about InSight as it enters the atmosphere and descends to the planet’s surface.
The job of acting as a data relay will fall to NASA’s Mars Reconnaissance Orbiter (MRO), which has been in orbit of Mars since 2006. However, the MarCOs will also be monitoring InSight to see if future missions will be capable of bringing their own relay to Mars, rather than having to rely on an orbiter that is already there. They may also demonstrate a number of experimental technologies, which includes their radio and propulsion systems.
The main attraction though, are the high-gain antennas which will be providing information on InSights’ progress. At the moment, the team has received early confirmation that the antennas have successfully deployed, but they will continue to test them in the weeks ahead. If all goes according to plan, the MarCOs could demonstrate the ability of CubeSats to act not only as relays, but also their ability to gather information on other planets.
In other words, if the MarCOs are able to make it to Mars and track InSight’s progress, NASA and other agencies may contemplate mounting full-scale missions using CubeSats – sending them to the Moon, Mars, or even beyond. Later this month, the MarCOs will attempt their first trajectory correction maneuvers, which will be the first such maneuver are performed by CubeSats.
In the meantime, be sure to check out this video of the MarCO mission, courtesy of NASA 360:
From space, Venus looks like a big, opaque ball. Thanks to its extremely dense atmosphere, which is primarily composed of carbon dioxide and nitrogen, it is impossible to view the surface using conventional methods. As a result, little was learned about its surface until the 20th century, thanks to development of radar, spectroscopic and ultraviolet survey techniques.
Interestingly enough, when viewed in the ultraviolet band, Venus looks like a striped ball, with dark and light areas mingling next to one another. For decades, scientists have theorized that this is due to the presence of some kind of material in Venus’ cloud tops that absorbs light in the ultraviolet wavelength. In the coming years, NASA plans to send a CubeSat mission to Venus in the hopes of solving this enduring mystery.
The mission, known as the CubeSat UV Experiment (CUVE), recently received funding from the Planetary Science Deep Space SmallSat Studies (PSDS3) program, which is headquartered as NASA’s Goddard Space Flight Center. Once deployed, CUVE will determine the composition, chemistry, dynamics, and radiative transfer of Venus’ atmosphere using ultraviolet-sensitive instruments and a new carbon-nanotube light-gathering mirror.
The mission is being led by Valeria Cottini, a researcher from the University of Maryland who is also CUVE’s Principle Investigator (PI). In March of this year, NASA’s PSDS3 program selected it as one of 10 other studies designed to develop mission concepts using small satellites to investigate Venus, Earth’s moon, asteroids, Mars and the outer planets.
Venus is of particular interest to scientists, given the difficulties of exploring its thick and hazardous atmosphere. Despite the of NASA and other space agencies, what is causing the absorption of ultra-violet radiation in the planet’s cloud tops remains a mystery. In the past, observations have shown that half the solar energy the planet receives is absorbed in the ultraviolet band by the upper layer of its atmosphere – the level where sulfuric-acid clouds exist.
Other wavelengths are scattered or reflected into space, which is what gives the planet its yellowish, featureless appearance. Many theories have been advanced to explain the absorption of UV light, which include the possibility that an absorber is being transported from deeper in Venus’ atmosphere by convective processes. Once it reaches the cloud tops, this material would be dispersed by local winds, creating the streaky pattern of absorption.
The bright areas are therefore thought to correspond to regions that do not contain the absorber, while the dark areas do. As Cottini indicated in a recent NASA press release, a CubeSat mission would be ideal for investigating these possibilities:
“Since the maximum absorption of solar energy by Venus occurs in the ultraviolet, determining the nature, concentration, and distribution of the unknown absorber is fundamental. This is a highly-focused mission – perfect for a CubeSat application.”
Such a mission would leverage recent improvements in miniaturization, which have allowed for the creation of smaller, box-sized satellites that can do the same jobs as larger ones. For its mission, CUVE would rely on a miniaturized ultraviolet camera and a miniature spectrometer (allowing for analysis of the atmosphere in multiple wavelengths) as well as miniaturized navigation, electronics, and flight software.
Another key component of the CUVE mission is the carbon nanotube mirror, which is part of a miniature telescope the team is hoping to include. This mirror, which was developed by Peter Chen (a contractor at NASA Goddard), is made by pouring a mixture of epoxy and carbon nanotubes into a mold. This mold is then heated to cure and harden the epoxy, and the mirror is coated with a reflective material of aluminum and silicon dioxide.
In addition to being lightweight and highly stable, this type of mirror is relatively easy to produce. Unlike conventional lenses, it does not require polishing (an expensive and time-consuming process) to remain effective. As Cottini indicated, these and other developments in CubeSat technology could facilitate low-cost missions capable of piggy-backing on existing missions throughout the Solar System.
“CUVE is a targeted mission, with a dedicated science payload and a compact bus to maximize flight opportunities such as a ride-share with another mission to Venus or to a different target,” she said. “CUVE would complement past, current, and future Venus missions and provide great science return at lower cost.”
The team anticipates that in the coming years, the probe will be sent to Venus as part of a larger mission’s secondary payload. Once it reaches Venus, it will be launched and assume a polar orbit around the planet. They estimate that it would take CUVE one-and-a-half years to reach its destination, and the probe would gather data for a period of about six months.
If successful, this mission could pave the way for other low-cost, lightweight satellites that are deployed to other Solar bodies as part of a larger exploration mission. Cottini and her colleagues will also be presenting their proposal for the CUVE satellite and mission at the 2017 European Planetary Science Congress, which is being held from September 17th – 22nd in Riga, Latvia.
One of the defining characteristics of the modern era of space exploration is the open nature of it. In the past, space was a frontier that was accessible only to two federal space agencies – NASA and the Soviet space program. But thanks to the emergence of new technologies and cost-cutting measures, the private sector is now capable of providing their own launch services.
In addition, academic institutions and small countries are now capable of building their own satellites for the purposes of conducting atmospheric research, making observations of Earth, and testing new space technologies. It’s what is known as the CubeSat, a miniaturized satellite that is allowing for cost-effective space research.
Structure and Design:
Also known as nanosatellites, CubeSats are built to standard dimensions of 10 x 10 x 11 cm (1 U) and are shaped like cubes (hence the name). They are scalable, coming in versions that measure 1U, 2Us, 3Us, or 6Us on a side, and typically weigh less than 1.33 kg (3 lbs) per U. CubSats of 3Us or more are the largest, being composed of three units stacked lengthwise with a cylinder encasing them all.
In recent years larger CubeSat platforms have been proposed, which include a 12U model (20 x 20 x 30 cm or 24 x 24 x 36 cm), that would extend the capabilities of CubeSats beyond academic research and testing new technologies, incorporating more complex science and national defense goals.
The main reason for miniaturizing satellites is to reduce the cost of deployment, and because they can be deployed in the excess capacity of a launch vehicle. This reduces the risks associated with missions where additional cargo has to be piggybacked to the launcher, and also allows for cargo changes on short notice.
They can also be made using commercial off-the-shelf (COTS) electronics components, which makes them comparably easy to create. Since CubeSats missions are often made to very Low Earth Orbits (LEO), and experience atmospheric reentry after just days or weeks, radiation can largely be ignored and standard consumer-grade electronics may be used.
CubeSats are built from four specific types of aluminum alloy to ensure that they have the same coefficient of thermal expansion as the launch vehicle. The satellites are also coated with a protective oxide layer along any surface that comes into contact with the launch vehicle to prevent them from being cold welded into place by extreme stress.
CubeSats often carry multiple on-board computers for the sake of carrying out research, as well providing for attitude control, thrusters, and communications. Typically, other on-board computers are included to ensure that the main computer is not overburdened by multiple data streams, but all other on-board computers must be capable of interfacing with it.
Typically, a primary computer is responsible for delegating tasks to other computers – such as attitude control, calculations for orbital maneuvers, and scheduling tasks. Still, the primary computer may be used for payload-related tasks, like image processing, data analysis, and data compression.
Miniaturized components provide attitude control, usually consisting of reaction wheels, magnetorquers, thrusters, star trackers, Sun and Earth sensors, angular rate sensors, and GPS receivers and antennas. Many of these systems are often used in combination in order to compensate for shortcomings, and to provide levels of redundancy.
Sun and star sensors are used to provide directional pointing, while sensing the Earth and its horizon is essential for conducting Earth and atmospheric studies. Sun sensors are also useful in ensuring that the CubsSat is able to maximize its access to solar energy, which is the primary means of powering a CubeSat – where solar panels are incorporated into the satellites outer casing.
Meanwhile, propulsion can come in a number of forms, all of which involve miniaturized thrusters providing small amounts of specific impulse. Satellites are also subject to radiative heating from the Sun, Earth, and reflected sunlight, not to mention the heat generated by their components.
As such, CubeSat’s also come with insulation layers and heaters to ensure that their components do not exceed their temperature ranges, and that excess heat can be dissipated. Temperature sensors are often included to monitor for dangerous temperature increases or drops.
For communications, CubeSat’s can rely on antennae that work in the VHF, UHF, or L-, S-, C- and X-bands. These are mostly limited to 2W of power due to the CubeSat’s small size and limited capacity. They can be helical, dipole, or monodirection monopole antennas, though more sophisticated models are being developed.
CubeSats rely on many different methods of propulsion, which has in turn led to advancements in many technologies. The most common methods includes cold gas, chemical, electrical propulsion, and solar sails. A cold gas thruster relies on inert gas (like nitrogen) which is stored in a tank and released through a nozzle to generate thrust.
As propulsion methods go, it is the simplest and most useful system a CubeSat can use. It is also one of the safest too, since most cold gases are neither volatile nor corrosive. However, they have limited performance and cannot achieve high impulse maneuvers. Hence why they are generally used in attitude control systems, and not as main thrusters.
Chemical propulsion systems rely on chemical reactions to produce high-pressure, high-temperature gas which is then directed through a nozzle to create thrust. They can be liquid, solid, or a hybrid, and usually come down to the combination of chemicals combined with a catalysts or an oxidizer. These thrusters are simple (and can therefore be miniaturized easily), have low power requirements, and are very reliable.
Electric propulsion relies on electrical energy to accelerate charged particles to high speeds – aka. Hall-effect thrusters, ion thrusters, pulsed plasma thrusters, etc. This method is beneficial since it combines high specific-impulse with high-efficiency, and the components can be easily miniaturized. A disadvantage is that they require additional power, which means either larger solar cells, larger batteries, and more complex power systems.
Solar sails are also used as a method for propulsion, which is beneficial because it requires no propellant. Solar sails can also be scaled to the CubSat’s own dimensions, and the satellite’s small mass results in the greater acceleration for a given solar sail’s area.
However, solar sails still need to be quite large compared to the satellite, which makes mechanical complexity an added source of potential failure. At this time, few CubeSats have employed a solar sail, but it remains an area of potential development since it is the only method that needs no propellant or involves hazardous materials.
Because the thrusters are miniaturized, they create several technical challenges and limitations. For instance, thrust vectoring (i.e. gimbals) is impossible with smaller thrusters. As such, vectoring must instead be achieved by using multiple nozzles to thrust asymmetrically or using actuated components to change the center of mass relative to the CubeSat’s geometry.
Beginning in 1999, California Polytechnic State University and Stanford University developed the CubeSat specifications to help universities worldwide to perform space science and exploration. The term “CubeSat” was coined to denote nano-satellites that adhere to the standards described in the CubeSat design specifications.
These were laid out by aerospace engineering professor Jordi Puig-Suari and Bob Twiggs, from the Department of Aeronautics & Astronautics at Stanford University. It has since grown to become an international partnership of over 40 institutes that are developing nano-satellites containing scientific payloads.
Initially, despite their small size, academic institutions were limited in that they were forced to wait, sometimes years, for a launch opportunity. This was remedied to an extent by the development of the Poly-PicoSatellite Orbital Deployer (otherwise known as the P-POD), by California Polytechnic. P-PODs are mounted to a launch vehicle and carry CubeSats into orbit and deploy them once the proper signal is received from the launch vehicle.
The purpose of this, according to JordiPuig-Suari, was “to reduce the satellite development time to the time frame of a college student’s career and leverage launch opportunities with a large number of satellites.” In short, P-PODs ensure that many CubeSats can be launched at any given time.
Several companies have built CubeSats, including large-satellite-maker Boeing. However, the majority of development comes from academia, with a mixed record of successfully orbited CubeSats and failed missions. Since their inception, CubeSats have been used for countless applications.
For example, they have been used to deploy Automatic Identification Systems (AIS) to monitor marine vessels, deploy Earth remote sensors, to test the long term viability of space tethers, as well as conducting biological and radiological experiments.
Within the academic and scientific community, these results are shared and resources are made available by communicating directly with other developers and attending CubeSat workshops. In addition, the CubeSat program benefits private firms and governments by providing a low-cost way of flying payloads in space.
In 2010, NASA created the “CubeSat Launch Initiative“, which aims to provide launch services for educational institutions and non-profit organizations so they can get their CubeSats into space. In 2015, NASA initiated its Cube Quest Challenge as part of their Centennial Challenges Programs.
With a prize purse of $5 million, this incentive-competition aimed to foster the creation of small satellites capable of operating beyond low Earth orbit – specifically in lunar orbit or deep space. At the end of the competition, up to three teams will be selected to launch their CubeSat design aboard the SLS-EM1 mission in 2018.
NASA’s InSight lander mission (scheduled to launch in 2018), will also include two CubeSats. These will conduct a flyby of Mars and provide additional relay communications to Earth during the lander’s entry and landing.
Designated Mars Cube One (MarCO), this experimental 6U-sized CubeSat will will be the first deep-space mission to rely on CubeSat technology. It will use a high-gain, flat-paneled X-band antenna to transmit data to NASA’s Mars Reconnaissance Orbiter (MRO) – which will then relay it to Earth.
Making space systems smaller and more affordable is one of the hallmarks of the era of renewed space exploration. It’s also one of the main reasons the NewSpace industry has been growing by leaps and bounds in recent years. And with greater levels of participation, we are seeing greater returns when it comes to research, development and exploration.
The “impossible” EM Drive (also known as the RF resonant cavity thruster) is one of those concepts that just won’t seem to die. Despite being subjected to a flurry of doubts and skepticism from the beginning that claim its too good to be true and violates the laws of physics, the EM Drive seems to be clearing all the hurdles placed in its way.
For years now, one of the most lingering comments has been that the technology has not passed peer-review. This has been the common retort whenever news of successful tests have been made. But, according to new rumors, the EM Drive recently did just that, as the paper that NASA submitted detailing the successful tests of their prototype has apparently passed the peer review process.
Now before anyone gets too excited, a quick reality check is necessary. At this time, everything said by Dr. Rodal has yet to be confirmed, and the comment has since been deleted. However, in his comment, Rodal did specify the paper would be titled “Measurement of Impulsive Thrust from a Closed Radio Frequency Cavity in Vacuum”.
He also named the papers authors, which includes Harold White – the Advanced Propulsion Team Lead for the Johnson Space Center’s Advanced Propulsion Physics Laboratory (aka. Eagleworks). Paul March was also named, another member of Eagleworks and someone who is associated with past tests.
On top of all that, the IB Times story indicated that he also posted information that appeared to be taken from the paper’s abstract:
“Thrust data in mode shape TM212 at less than 8106 Torr environment, from forward, reverse and null tests suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 mN/Kw ()”.
But even if the rumor is true, there are other things that need to be taken into account. For instance, the peer-review process usually means that an independent panel of experts reviewed the work and determined that it is sufficient to merit further consideration. It does not mean the conclusions reached are correct, or that they won’t be subject to contradiction by follow-up investigations.
However, we may not have to wait long before the next test to happen. Guido Fetta is the CEO of Cannae Inc., the inventor of the Cannae Drive (which is based on Shawyer’s design). As he announced on August 17th of this year, the Cannae engine would be launched into space on board a 6U CubeSat in order to conduct tests in orbit.
As Fetta stated on their website, Cannae has formed a new company (Theseus Space Inc.) to commercialize their thruster technology, and will use this deployment to see if the Cannae drive can generate thrust in a vacuum:
“Theseus is going to be launching a demo cubesat which will use Cannae thruster technology to maintain an orbit below a 150 mile altitude. This cubesat will maintain its extreme LEO altitude for a minimum duration of 6 months. The primary mission objective is to demonstrate our thruster technology on orbit. Secondary objectives for this mission include orbital altitude and inclination changes performed by the Cannae-thruster technology.”
By remaining in orbit for six months, the company will have ample time to see if the satellite is experiencing thrust without the need for propellant. While no launch date has been selected yet, it is clear that Fetta wants to move forward with the launch as soon as possible.
And as David Hambling of Popular Mechanics recently wrote, Fetta is not alone in wanting to get orbital tests underway. A team of engineers in China is also hoping to test their design of the EM Drive in space, and Shawyer himself wants to complete this phase before long. One can only hope their drives all prove equal to the enterprise!
While this could be an important milestone for the EM Drive, it still has a long way to go before NASA and other space agencies consider using them. So we’re still a long away from spacecraft that can send a crewed mission to Mars in 70 days (or one to Pluto in just 18 months).
Ever since they were first produced, carbon nanotubes have managed to set off a flurry excitement in the scientific community. With applications ranging from water treatment and electronics, to biomedicine and construction, this should come as no surprise. But a team of NASA engineers from the Goddard Space Flight Center in Greenbelt, Maryland, has pioneered the use of carbon nanotubes for yet another purpose – space-based telescopes.
Using carbon nanotubes, the Goddard team – which is led by Dr. Theodor Kostiuk of NASA’s Planetary Systems Laboratory and Solar System Exploration Division – have created a revolutionary new type of telescope mirror. These mirrors will be deployed as part of a CubeSat, one which may represent a new breed of low-cost, highly effective space-based telescopes.
This latest innovation also takes advantage of another field that has seen a lot of development of late. CubeSats, like other small satellites, have been playing an increasingly important role in recent years. Unlike the larger, bulkier satellites of yesteryear, miniature satellites are a low-cost platform for conducting space missions and scientific research.
Beyond federal space agencies like NASA, they also offer private business and research institutions the opportunity to conduct communications, research and observation from space. On top of that, they are also a low-cost way to engage students in all phases of satellite construction, deployment, and space-based research.
Granted, missions that rely on miniature satellites are not likely to generate the same amount of interest or scientific research as large-scale operations like the Juno mission or the New Horizons space probe. But they can provide vital information as part of larger missions, or work in groups to gather greater amounts of data.
With the help of funding from Goddard’s Internal Research and Development program, the team created a laboratory optical bench made of regular off-the-shelf components to test the telescope’s overall design. This bench consists of a series of miniature spectrometers tuned to the ultraviolet, visible, and near-infrared wavelengths, which are connected to the focused beam of the nanotube mirrors via an optic cable.
Using this bench, the team is testing the optical mirrors, seeing how they stand up to different wavelengths of light. Peter Chen – the president of Lightweight Telescopes a Maryland-based company – is one of the contractors working with the Goddard team to create the CubeSat telescope. As he was quoted as saying by a recent NASA press release:
“No one has been able to make a mirror using a carbon-nanotube resin. This is a unique technology currently available only at Goddard. The technology is too new to fly in space, and first must go through the various levels of technological advancement. But this is what my Goddard colleagues (Kostiuk, Tilak Hewagama, and John Kolasinski) are trying to accomplish through the CubeSat program.
Unlike other mirrors, the one created by Dr. Kostiuk’s team was fabricated out of carbon nanotubes embedded in an epoxy resin. Naturally, carbon nanotubes offer a wide range of advantages, not the least of which are structural strength, unique electrical properties, and efficient conduction of heat. But the Goddard team also chose this material for their lenses because it offers a lightweight, highly stable and easily reproducible option for creating telescope mirrors.
What’s more, mirrors made of carbon-nanotubes do not require polishing, which is a time-consuming and expensive process when it comes to space-based telescopes. The team hopes that this new method will prove useful in creating a new class of low-cost, CubeSat space telescopes, as well as helping to reduce costs when it comes to larger ground-based and space-based telescopes.
Such mirrors would be especially useful in telescopes that use multiple mirror segments (like the Keck Observatory at Mauna Kea and the James Webb Space Telescope). Such mirrors would be a real cost-cutter since they can be easily produced and would eliminate the need for expensive polishing and grinding.
Other potential applications include deep-space communications, improved electronics, and structural materials for spacecraft. Currently, the production of carbon nanotubes is quite limited. But as it becomes more widespread, we can expect this miracle material to be making its way into all aspects of space exploration and research.
The company lost 26 satellites in the explosion. But within nine days of the Oct. 28 event, Planet Labs had a partial backup plan — send two replacements last-minute on an upcoming SpaceX Falcon 9 launch.
In what Planet Labs’ Robbie Schingler calls “the future of aerospace”, almost immediately after the explosion Planet Labs began working with NanoRacks, which launches its satellites from the space station, to find a replacement flight. Half of Planet Labs’ employees began building satellites, while the other half began working through the regulations and logistics. They managed to squeeze two satellites last-minute on to the next SpaceX manifest, which is scheduled to launch in December.
“In space, each element is very difficult to get right by itself, and it takes an ecosystem to deliver a capability this quickly,” wrote Schingler, a president and co-founder of the company, in a blog post last week.
“Central to making this possible was developing our own custom design of the satellite that is free from specialty suppliers (thus decreasing lead time) and having a spacecraft design optimized for manufacturing and automated testing. Moreover, we certainly couldn’t have done it without the collaboration from NanoRacks and support from NASA, and we thank them for their support. This is a great example for how to create a resilient aerospace ecosystem.”
There’s no word on how they will replace the other satellites, nor how this will affect Planet Labs’ vision (explained in this March TED talk) to have these small sentinels frequently circling Earth to provide near-realtime information on what is happening with our planet. But the company acknowledged that space is hard and satellites do get lost from time to time.
One doesn’t take two cubesats and rub them together to make static electricity. Rather, you send them on a brief space voyage to low-earth orbit (LEO) and space them apart some distance and voilà, you have a telescope. That is the plan of NASA’s Goddard Space Flight Center engineers and also what has been imagined by several others.
Cubesats are one of the big crazes in the new space industry. But nearly all that have flown to-date are simple rudderless cubes taking photos when they are oriented correctly. The GSFC engineers are planning to give two cubes substantial control of their positions relative to each other and to the Universe surrounding them. With one holding a telescope and the other a disk to blot out the bright sun, their cubesat telescope will do what not even the Hubble Space Telescope is capable of and for far less money.
The 1U, the 3U, the 9U – these are all cubesats of different sizes. They all have in common the unit size of 1. A 1U cubesat is 10 x 10 x 10 centimeters cubed. A cube of this size will hold one liter of water (about one quart) which is one kilogram by weight. Or replace that water with hydrazine and you have very close to 1 kilogram of mono-propellent rocket fuel which can take a cubestat places.
GSFC aerospace engineers, led by Neerav Shah, don’t want to go far, they just want to look at things far away using two cubesats. Their design will use one as a telescope – some optics and a good detector –and the other cubesat will stand off about 20 meters, as they plan, and function as a coronagraph. The coronagraph cubesat will function as a sun mask, an occulting disk to block out the bright rays from the surface of the Sun so that the cubesat telescope can look with high resolution at the corona and the edge of the Sun. To these engineers, the challenge is keeping the two cubesats accurately aligned and pointing at their target.
Only dedicated Sun observing space telescopes such as SDO, STEREO and SOHO are capable of blocking out the Sun, but their coronagraphs are limited. Separating the coronagraph farther from the optics markedly improves how closely one can look at the edge of a bright object. With the corongraph mask closer to the optics, more bright light will still reach the optics and detectors and flood out what you really want to see. The technology Shah and his colleagues develop can be a pathfinder for future space telescopes that will search for distant planets around other stars – also using a coronagraph to reveal the otherwise hidden planets.
The engineers have received a $8.6-million investment from the Defense Advanced Research Project Agency (DARPA) and are working in collaboration with the Maryland-based Emergent Space Technologies.
The challenge of GSFC engineers is giving two small cubesats guidance, navigation, and control (GN&C) as good as any standard spacecraft that has flown. They plan on using off-the-shelf technology and there are many small and even large companies developing and selling cubesat parts.
This is a sorting out period for the cubesat sector, if you will, of the new space industry. Sorting through the off-the-shelf components, the GSFC engineers led by Shah will pick the best in class. The parts they need are things like tiny sun sensors and star sensors, laser beams and tiny detectors of those beams, accelerometers, tiny gyroscopes or momentum wheels and also small propulsion systems. The cubesat industry is pretty close to having all these ready as standard issue. The question then is what do you do with tiny satellites in low-Earth orbit (LEO). Telescopes for earth-observing are already making headway and scopes for astronomy are next. There are also plans to venture out to interplanetary space with tiny and capable cubesat space probes.
Whether one can sustain a profit for a company built on cubesats remains a big question. Right now those building cubesats to customer specs are making a profit and those making the tiny picks and shovels for cubesats are making profits. The little industry may be overbuilt which in economic parlance might be only natural. Many small startups will fail. However, for researchers at universities and research organizations like NASA, cubesats have staying power because they reduce cost by their low mass and size, and the low cost of the components to make them function. The GSFC effort will determine how quickly cubesats begin to do real work in the field of astronomy. Controlling attitude and adding propulsion is the next big thing in cubesat development.
Clearly, the sky is not the limit for balloon launcher Zero2Infinity. Based in Barcelona, Spain, the company announced this week their plans to launch payloads to orbit using a balloon launch system. The Rockoon is a portmanteau, as Lewis Carroll would have said: the blend of the words rocket and balloon.
The launch system announced by the company is called Bloostar. The Rockoon system begins with a balloon launch to stratospheric altitudes followed by the igniting of a 3 stage rocket to achieve orbit. The Rockoon concept is not new. Dr. James Van Allen with support from the US Navy developed and launched the first Rockoons in 1949. Those were just sounding rockets, Bloostar will take payloads to low-earth orbit and potentially beyond.
The advantage of rocket launch from a balloon is that it takes the Earth’s atmosphere out as a factor in design and as a impediment to reaching orbit. The first phase of the Bloostar system takes out 99% of the Earth’s atmosphere by reaching an altitude of over 20 km (>65,000 feet). Aerodynamics is not a factor so the stages are built out rather than up. The stages of the Bloostar design are a set of concentric rings which are sequentially expended as it ascends to orbit.
Zero2Infinity is developing a liquid fuel engine that they emphasize is environmentally friendly. The first stage firing of Bloostar will last 160 seconds, reach 250 km of altitude and an inertial speed of 3.7 km/s. This is about half the velocity necessary for reach a stable low earth orbit. The second stage will fire for 230 seconds and achieve an altitude of 530 km with velocity of 5.4 km/s. The 3rd and final stage motor will fire at least twice with a coast period to achieve the final orbit. Zero2Infinity states that their Bloostar system will be capable of placing a 75kg (165 lbs) payload into a 600 km (372 mi) sun-synchronous orbit. In contrast, the International Space Station orbits at 420 km (260 mi) altitude.
For the developing cubesat space industry, a 75 kg payload to orbit is huge. A single cubesat 10x10x10 cm (1U) will typically weigh about 1 kg so Bloostar would be capable of launching literally a constellation of cubesats or in the other extreme, a single micro-satellite with potentially its own propulsion system to go beyond low-earth orbit.
The Rockoon concept is not unlike what Scaled Composites undertakes with a plane and rocket. Their Whiteknight planes lift the SpaceShips to 50,000 feet for takeoff whereas the Zero2Infinity balloon will loft Bloostar to 65,000 feet or higher. The increased altitude of the balloon launch reduces the atmospheric density to half of what it is at 50,000 feet and altogether about 8% of the density at sea level.
The act of building and launching a stratospheric balloon to 30 km (100,000 feet) altitude with >100 kg instrument payloads is a considerable accomplishment. This is just not the releasing of a balloon but involves plenty of logistics and telecommunications with instrumentation and also the returning of payloads safely to Earth. This is clearly half of what is necessary to reach orbit.
Bloostar is blazing new ground in Spain. The ground tests of their liquid fuel rocket engine are the first of its kinds in the country. Zero2Infinity began launching balloons in 2009. The founder and CEO, Jose Mariano Lopez-Urdiales is an aeronautical engineer educated in Spain with R&D experience involving ESA, MIT and Boeing. He has speerheaded organizations and activities in his native Spain. In 2002 he presented to the World Space Congress in Houston, the paper “The Role of Balloons in the Future Development of Space Tourism”.