Bloostar, designed by the private Spanish company Zero 2 Infinity to launch small satellites in Low Earth Orbit (LEO), reinvents access to outer space, thanks to stratospheric balloons. Bloostar is a launch vehicle currently in development, intended to compete in the small satellite launch market. It is based on the rockoon concept: the first stage of the ascent is conducted by the use of a high-altitude balloon up to thirty kilometres, where the rocket platform is ignited and detached from the balloon to insert the payload into Low Earth Orbit. With the miniaturization of space technologies, the number of satellites to be launched in the coming years will grow strongly. Bloostar might thus become an option.
Zero 2 Infinity, which has been operating since 2009 high altitude balloons and flying technical, scientific and commercial loads more than thirty kilometres above the ground, is a private Spanish company founded in 2009 and headquartered in Barcelona, Spain. It is presently developing high-altitude balloons to provide access to near space (or mesosphere, the layer of the Earth’s atmosphere that is directly above the stratosphere and directly below the thermosphere) and Low Earth Orbit (LEO) using a balloon-borne pod and a balloon-borne launcher.
Development of Bloostar began in 2013. The first flight test was successfully conducted in March 2017, in which a less-than-half-scale prototype of the upper two stages was carried to twenty-five kilometres altitude by balloon, separated, made a short burn using a small solid motor, and then was recovered intact by parachute.
“Bloostar places your satellite in the orbit you want. We ensure you are ready to launch by testing your satellite in Near Space” says the Spanish company’s website. The design is intended to be capable of delivering a 140-kilogram payload to a 200-kilometre Low Earth Orbit (LEO), or a 75-kilogram payload to a 600-kilometre Sun-synchronous orbit (also called a heliosynchronous orbit, a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet’s surface at the same local mean solar time; technically, it is an orbit arranged so that it precesses through one complete revolution each year, so it always maintains the same relationship with the Sun).
The launch vehicle is composed of a set of liquid fuel engines clustered as concentric toroids attached to the central payload. Each toroid works as a stage during the rocket climb once it has been ignited from around thirty kilometres above ground level. The stages are progressively separated of the vehicle, similarly to conventional satellite launch using a rocket with parallel staging.
The design includes a total of thirteen engines split across three stages, all using methalox (liquid methane and liquid oxygen) fuel. All available engines will fire simultaneously but only the fuel tank in the outermost stage will be depleted at a time, increasing performance. As the engines will only ever fire at very high altitude, all thirteen will be optimized to produce maximum thrust in vacuum or near-vacuum conditions, similar to the upper-stage engines of conventional rockets.
The use of several toroid-shaped stages results in an increased stand-off distance to the sonic line during atmospheric entry, reducing the possibility of damaging the stages because of the high temperatures reached. Another promoted advantage is the capability to launch satellites with no need of folding them, as a flat-shaped vehicle is capable of fitting panel-deployed satellites right from the launch site.
The balloon components will be landed and potentially reused; the Bloostar rocket launch vehicle “has been designed to be reusable, technically, but not as part of the business plan. The engines burn methane and oxygen for many reasons, but one is that it creates less soot and leaves the engines reusable. Also, the shape of a torus has been selected to reduce the aero-heating on re-entry. The optimal shape in vacuum is similar to the optimal shape for re-entry (blunt). The optimal shape for ascent is very different (slender). Bloostar has been designed from its ignition taking into account the way back down. It’s easier to do if the way up is taken care of by the balloon”.
Recovery will be attempted, however, and consideration has been given for an eventual system by which the first stage will descent top-down, using a portion of its dorsal fairing as an ablative heat shield, and slow to be caught in a sea-based net.
Zero 2 Infinity wants, like other outer space private companies, to democratize access to near space or outer space for small satellites. It has recently (2017) successfully tested a prototype of its Bloostar launcher. For this test flight, Bloostar was brought over twenty-five kilometres above sea level by a balloon off the coast of Spain. As it took off, it turned on its engine and moved away, reaching a speed of about sixty-two metres per second, according to the video that the company has broadcasted. The purpose of this flight was not to put a payload into Low Earth Orbit (LEO) but to check the maturity of certain technological choices (telemetry systems in a space environment, stabilization, parachute…).
This small three-stage launcher, totalling nine identical engines, has the unique feature of launching into outer space from a balloon at an altitude of about thirty kilometres. This is the least risky launching technique, because the farther away the Earth’s surface is, the lower the resistance of the air is. This balloon method makes it possible to launch satellites with great flexibility. A notice of just two weeks is enough to prepare the machine, and for a price much lower than the prices charged on the market.
Zero 2 Infinity
Zero 2 Infinity has been testing high-altitude balloons and launching small payloads to high altitudes for scientific institutions and commercial firms for testing elements above most of the Earth’s atmosphere. Their launch system has a significantly lower impact on the environment, an advantage over conventional systems.
Among its projects are Bloostar, but also Bloon. Bloon is a zero emission craft in development, which consists of a high-altitude balloon-borne capsule to perform manned flights to near space and a steerable parachute system for returning autonomously to Earth. It also refers to the balloon-borne craft prototype range of the same company: Bloon, minibloon, microbloon and nanobloon which are differentiated among them by their size.
Considering that only a helium balloon is responsible for lifting the load above most of the atmosphere, it is considered a zero emission craft. With this technology, Bloon would carry up to four passengers and two pilots to an altitude as high as thirty-six kilometres. The vehicle would take from one and a half to two hours to reach maximum altitude, and then stay there for up to two hours, with a final descent by steerable parachute after releasing the balloon, using airbags to smooth the landing.
The rockoon concept
A rockoon (from rocket and balloon) is a solid fuel sounding rocket that, rather than being immediately lit while on the ground, is first carried into the upper atmosphere by a gas-filled balloon, then separated from the balloon and ignited. This allows the rocket to achieve a higher altitude, as the rocket does not have to move under power through the lower and thicker layers of the atmosphere.
A serious disadvantage is that balloons cannot be steered and consequently neither the direction the launched rocket moves in nor the region where it will fall is easily adjustable. Therefore, a large area for the fall of the rocket is required for safety reasons.
Bloostar’s legal status
The term Object in reference to outer space was first used in 1961 in General Assembly Resolution 1721 (XVI) titled International cooperation in the peaceful uses of outer space to describe any object launched by States into outer space. Professor Bin Cheng, a world authority on International Air and Space Law, has noted that members of the COPUOS during negotiations over the space treaties treated spacecraft and space vehicles as synonymous terms. The Space Object can be considered as the “conventional launcher”, the “reusable launcher”, the “satellite”, the “orbital station”, the “probe”, the “impactor”, the “space telescope”…
The term “space object” is not precisely defined by the Onusian space treaties. Let’s note that the five outer space treaties use such phrases as “objects launched into outer space”, object placed “in orbit around the Earth”, “in orbit around or other trajectory to or around the Moon”, or “around other celestial bodies within the solar system, other than the Earth”. Some of the treaties refer also to “spacecraft”, or “landed or constructed on a celestial body”, “man-made space objects”, “space vehicle”, “supplies”, “equipment”, “installations”, “facilities” and “stations”.
Let’s remember that “A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose”, article 31 of the Vienna Convention on the Law of Treaties of 1969. In addition, “Recourse may be had to supplementary means of interpretation, including the preparatory work of the treaty and the circumstances of its conclusion, in order to confirm the meaning resulting from the application of article 31, or to determine the meaning when the interpretation according to article 31: (a) leaves the meaning ambiguous or obscure; or (b) leads to a result which is manifestly absurd or unreasonable”, article 32 of the Vienna Convention on the Law of Treaties of 1969.
The term space object effectively triggers application of much of both the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (entered into force in October 1967) and the Agreement on the Rescue of Astronauts, the Return of Astronauts and the Return of Objects Launched into Outer Space (entered into force in December 1968). Article VII of the first declares that “Each State Party to the Treaty that launches or procures the launching of an object into outer space, including the Moon and other celestial bodies, and each State Party from whose territory or facility an object is launched, is internationally liable for damage to another State Party to the Treaty or to its natural or juridical persons by such object or its component parts on the Earth, in air space or in outer space, including the Moon and other celestial bodies”.
The Outer Space Treaty doesn’t really provide a definition for “object launched into outer space” other than an indication in Article VIII that it includes the “component parts” of the “object launched into outer space”. It states that “A State Party to the Treaty on whose registry an object launched into outer space is carried shall retain jurisdiction and control over such object, and over any personnel thereof, while in outer space or on a celestial body. Ownership of objects launched into outer space, including objects landed or constructed on a celestial body, and of their component parts, is not affected by their presence in outer space or on a celestial body or by their return to the Earth. Such objects or component parts found beyond the limits of the State Party to the Treaty on whose registry they are carried shall be returned to that State Party, which shall, upon request, furnish identifying data prior to their return”.
Let’s recall that a space object causing damage triggers international third-party liability under the Convention on International Liability for Damage Caused by Space Objects (entered into force in September 1972). Article I (d) of which enounces that “the term space object includes component parts of a space object as well as its launch vehicle and parts thereof”. Its Article II adds that “A launching State shall be absolutely liable to pay compensation for damage caused by its space object on the surface of the Earth or to aircraft in flight”. This is very interesting because it completes the definition of a space object by adding that a “launch vehicle and parts thereof” is included in the term space object.
The term launch vehicle is not defined by the five Onusian treaties but only mentioned twice: Article I (d) of the Convention on International Liability for Damage Caused by Space Objects and Article I (b) of the Convention on Registration of Objects Launched into Outer Space. A “launch vehicle” or “carrier rocket”, sometimes defined as “a rocket-powered vehicle used to send artificial satellites or spacecraft into space”, is a rocket used to carry a payload from Earth’s surface through outer space, either to another surface point (sub-orbital transportation), or into outer space (Earth orbit or beyond). A launch system includes the launch vehicle, launch pad, vehicle assembly and fuelling systems, range safety, and other related infrastructure. We could therefore consider Bloostar a launch vehicle, and therefore, a space object.
As a conclusion, whether Bloostar is a space object or not, Article VII of the 1967 Outer State Treaty enounces that “Each State Party to the Treaty that launches or procures the launching of an object into outer space, including the Moon and other celestial bodies, and each State Party from whose territory or facility an object is launched, is internationally liable for damage to another State Party to the Treaty or to its natural or juridical persons by such object or its component parts on the Earth, in air space or in outer space, including the Moon and other celestial bodies”. Spain, from where Bloostar might operate, will be internationally liable for damage to another State Party to the Treaty or to its natural or juridical persons by such object or its component parts on the Earth, in air space or in outer space, including the Moon and other celestial bodies.
The future of orbital launch systems
Satellites launched from Earth require dedicated launch vehicles to propel them into the proper orbit. The cost for this launch scenario could be reduced considerably if there was another way to get the satellites into their optimal orbit. In the near future, we could see the development of new ways of launching objects in outer space. First of all, launches from aircraft could develop. Let’s mention Stratolaunch, which is not the first of its kind, since Stargazer, a Lockheed L-1011 TriStar built in 1974, was modified in 1994 to be used by Orbital ATK Inc. as a mother ship launch pad for Pegasus rockets; as of January 2017, forty-three rockets (containing ninety-four satellites) had been launched from it, using the Pegasus-H and Pegasus-XL configurations.
Also, LauncherOne, a two stage orbital launch vehicle is under development by Virgin Orbit since 2007. It is an air launch to orbit rocket (the method of launching rockets at altitude from a conventional horizontal-take-off aircraft, to carry satellites to Low Earth Orbit), designed to launch “smallsat” payloads of three hundred kilograms into Sun-synchronous orbit (a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet’s surface at the same local mean solar time), following air launch from a carrier aircraft at high altitude.
Also, thanks to 3D printing, satellites might soon be built in outer space and launched directly from a satellite or from a space station. The Japan Aerospace Exploration Agency (JAXA) found a way to cut the costs of this activity by designing a small satellite launcher, installed recently on the International Space Station (ISS). The International Space Station was designed to be used as both a microgravity laboratory, as well as a launch pad for Low Earth Orbit services. The Japan Aerospace Exploration Agency’s (JAXA) Kibō module, or Japanese Experiment Module (JEM), a Japanese science module for the International Space Station (ISS), includes a small satellite-deployment system called the J-SSOD.
Deploying CubeSats from the ISS has a number of benefits. Launching the vehicles aboard the logistics carrier of the ISS visiting vehicle reduces the vibration and loads they have to encounter during launch. In addition, they can be packed in protective materials so that the probability of CubeSat damage during launch is reduced significantly. In addition, the Low Earth Orbit allows a natural decay of the satellites, thus reducing the build-up of orbital debris.
Let’s hope that those way to launch will reduce the cost of sending objects in outer space and thus, democratize access to outer space!