Category Science

Scientists and engineers are continually working on new ways to carry expensive payloads into space. The X-34 is a small rocket designed to be launched by an aeroplanes. It is hoped that the X-34 will be able to minimize the cost of carrying satellites into orbit. The DC-XA was a new design for a single-stage-to-orbit vehicle. It made four successful flights before crashing. The Rotors is designed to work without the heavy technology needed to pump rocket fuel. Its rotor blades spin, literally throwing propellant into the combustion chamber.

RLVs as workhorse launch vehicles have yet to appear, however, for several reasons. The primary reason for the emphasis on expendable launch vehicles (ELVs) instead of RLVs has historically been the higher up-front development costs of RLV designs. In order to field fully reusable launch vehicles, reusable components and operations techniques must be developed along with the vehicle design. Although construction of RLVs has been possible, governments and commercial companies have been reluctant to provide the funding required to build RLVs that have higher initial costs, but that would reduce operating costs in the long-term. When the designs for the Space Shuttle fleet were first considered, fully-reusable concepts were introduced, and the original selected design was to have two reusable stages. Budgetary pressures, however, molded the vehicle into the partially-reusable system used today.

The materials and designs to construct TSTO RLVs have been available for 35 years, but innovations are still required to develop a SSTO vehicle that can transport payloads to orbit at low costs. Advances in propulsion and structural technology (such as new lightweight composite materials) have been made over the last few decades that are enabling the development of SSTO vehicles. SSTO vehicle technologies may be validated in the next few years with the testing of NASA’s X-33 and X-34 vehicles and with the development of commercial SSTO designs such as the Roton-C. Developments that will be demonstrated by the X-33 will include load-bearing fuel tanks and composite structures. Both the X-33 and Roton plan to use aerospike engines (the aerospike design has existed for decades it has yet to be fully flight tested).

Today there are several drivers that are pushing RLV development forward. The desire to reduce launch costs in the commercial and government markets is greater than ever. The growth in the number of proposed LEO satellite constellations for telecommunication applications has produced demand for low-cost launches, encouraging entrepreneurial aerospace companies to develop commercial RLVs to serve this market. RLV designs for space tourism applications have been seriously proposed in the last few years. The X PRIZESM competition is encouraging construction of passenger-carrying sub-orbital RLVs by over a dozen start-up companies by offering a $10 million prize to the first vehicle to demonstrate the capability to carry 3 people to a 100 km sub-orbital altitude and repeat the flight within 2 weeks.

Government programs are also a key source of RLV development. NASA’s current X-33 and X-34 RLV prototype and technology development programs grew out of a series of studies examining the next step following the Space Shuttle program. In 1985, NASA and the Department of Defense were directed by the President to devise a common plan to develop space transportation systems beyond the Space Shuttle. The resulting Space Transportation Architecture Study was focused on meeting civil and military launch needs, and endorsed examining air-breathing propulsion technologies, TSTO systems, and solid rocket boosters.

In 1905, Albert Einstein published his theory of special relativity. This stated that travel at the speed of light is impossible. He argued that the faster an object moves, the heavier it becomes, so that an object travelling at the speed of light would have infinite mass, which is impossible. Spacecraft are getting faster and faster but may never be able to reach the speeds needed to travel between stars.

If we ever want to travel to, ahem, galaxies far, far away, we’ll need to find a way of getting there within our lifetime. For example, travelling to Alpha Centauri, one of our closest galactic neighbours 4.35 light years away, would take approximately 70,000 years if we made the journey at the same speed as NASA’S Voyager 1 probe. Even Yoda would struggle with that time scale.

One way to push the boundaries of space exploration is to travel faster than light, which is a mindboggling, 670,616,629mph, or 1.07bn km/hr. By comparison, the fastest manmade spacecraft – NASA’S Juno Probe – briefly reached 165,000 mph (266,000 km/h).

But according to our understanding of the laws of physics, it’s impossible to break ‘c’, the cosmic speed limit set by Albert Einstein.

The main barrier that we – and most particles – have is mass. Any object with mass accelerates, gaining energy, but it always needs more to accelerate further. So, propelling us to the speed of light would take an infinite amount of energy. ‘There is simply no fuel source big enough to accelerate you or I to light speed,’ Peter William Millington, a research fellow at the University of Nottingham explained. But that hasn’t stopped scientists trying to find a workaround to this mammoth problem. Teams at the CERN laboratory in Switzerland tried to get neutrinos – the lightest known particles in the universe – to exceed the speed of light but failed.

However, their efforts were not without drama. In 2011, the OPERA (Oscillation Project with Emulsion tracking Apparatus) team made an announcement that promised to rewrite our understanding of the universe, by saying they had ‘high confidence’ that neutrinos had travelled faster than light, giving science fiction fans immediate hope that spacecraft might be possible. Theoretically, at least. However, it turned out that the results were wrong due to a faulty cable connection in the GPS system used to time the particles. This made their journey look around 73 nanoseconds speedier than it was. So for now, at least, we won’t be able to travel beyond the speed of light based on our current understanding of the laws of physics.

The X-33 is a single-stage-to-orbit reusable launch vehicle designed by NASA. It is currently a sized-down prototype of a new rocket design called the Venturestar, which will be built if the X-33 is successful. The Venturestar will be able to travel into space and back in one piece, without jettisoning any boosters or fuel tanks, and will lower the cost of putting one pound of payload into orbit by more than 90%.

Currently under construction, X-33 is the subscale prototype of the VentureStar single-stage-to-orbit reusable launch vehicle (RLV). The project is a joint effort of NASA and the Lockheed Martin Skunk Works. VentureStar is a potential successor to the Space Shuttle, providing low-cost access to orbit for satellites and humans. The major document on this CD-ROM is our exclusive reproduction of the incredibly detailed Critical Design Review (CDR). It might sound boring, but it isn’t: it contains every imaginable fact and graphic for this exciting project! This is one of the most innovative vehicles in aerospace history, and the CDR provides the full details with thousands of beautiful color cutaway drawings, schematics, and photographs. The illustrations are simply spectacular! Topics covered include: VentureStar Concepts and Systems, Aerospike XRS-2000 Engine and Fluid Systems, Vehicle Systems, Main Propulsion System, Structural, Mechanical Systems, Avionics and ! Software, Thermal Protection System, Flight Control System, Flight Analysis, Facilities, Operations and Ground Systems, Flight Test Program, Launch Site and Launch Pad. In addition, the CD includes up-to-date news and program status reports, a gallery of images, and even a computer-animated movie clip depicting the countdown and launch. As another title in the World Spaceflight News American Space Encyclopedia CD-ROM series, it is truly an authoritative source for spaceflight enthusiasts!

First off the X-33/ Venturestar was a significant scientific achievement. The RLV concept is the basis for our ability as inhabitants of our plant to pursue space exploration efficiently and effectively in the future. NASA has critical information available from the lessons learned on this project. Each contributor to the program pushed the limits of advanced technology as far as humanly possible. This book when reviewed in detail provides documentation crediting human imagination and the shape of things to come. Design, engineering, manufacturing, business management all contributed to the awesome technological capabilities that would stem from this project had it been completed. New materials never considered in the past were placed on this vehicle to prove the technology was space worthy. In the near future we will all benefit from knowledge that can be traced back to the X-33.

Some companies are already taking bookings for leisure trips into space. In 2001, the American millionaire Dennis Tito was the first “tourist” in space, flying into orbit in a Russian Sow: rocket. Other firms have already spent millions on designing hotels and condominiums on the Moon! As the price of traveling into space lessens, more and more people will make plans to go on the ultimate holiday in orbit.

Space tourism has experienced many false dawns. Companies have come and gone that have offered everything from trips to the Moon to a new home on Mars. But after broken promise after broken promise, things might be about to change.

Seven people have paid to go to space before, with American multimillionaire Dennis Tito becoming the first space tourist in 2001, flying to the International Space Station (ISS) on a Soyuz capsule to the tune of $20 million. Six more space tourists would follow in his footsteps, but despite hopes otherwise, little else followed. No space tourist has flown since 2009.

This year, however, we are expecting several private companies in the US to start taking humans to space, most for the first time. And, if all goes to plan, this could be a vital step towards making space more accessible – where paid trips and privately funded astronauts become the norm. “2019 does feel like the year that’s going to be the culmination of two decades of development work that have gone into space tourism,” says industry analyst Caleb Williams from consulting firm SpaceWorks. “And if we’re lucky, we’ll see the birth of an entirely new industry.”

One of those companies is Virgin Galactic, who on 13 December 2018 conducted their first trip to near-space. Two pilots, Mark Stucky and Frederick Sturckow, took Virgin’s spaceplane VSS Unity to an altitude of 82.7 kilometres (51.4 miles). This year, the company plans to conduct more test flights, with the possibility of taking its first passengers – founder Richard Branson being first of all – to space.

“We hope now to get into a regular cadence of space flights which will be historically unprecedented,” says Stephen Attenborough, commercial director at Virgin Galactic. “[2019] promises to be a turning point after many years of dedication, patience and hard work.”

NASA’s deep space 1 probe launched in 1998, was the first craft to use ion technology in space. It flew close to the near-Earth asteroid Braille (also known as 1992 KD), guided by an automated navigation system. Afterwards, it investigated the comet Borrelly, completing its mission in late 2001. Deep Space 1 is an experimental craft that is also testing several other new technologies, including more efficient solar panels, and an autonomous operations system, which allows the craft to think and act on its own. Its success has made scientists optimistic about the use of ion technology.

Deep Space 1 is the first interplanetary spacecraft to use an ion propulsion system for the primary delta-v maneuvers. The purpose of the mission is to validate a number of technologies, including ion propulsion and a high degree of spacecraft autonomy, on a flyby of an asteroid and two comets. The ion propulsion system has operated for a total of 3500 hours at engine power levels ranging from 0.48 to 1.94 kW and has completed the encounter with the asteroid 1992KD and the first set of deterministic burns required for a 2001 encounter with comet Wilson-Harrington. The system has worked extremely well after an initial grid short was cleared after launch. Operation during this primary mission phase has demonstrated all ion propulsion system and autonomous navigation functions. All propulsion system operating parameters are very close to the expected values with the exception of the thrust at higher power levels, which is about 2 percent lower than that calculated from the electrical parameters. This paper provides an overview of the system and presents the first flight validation data on an ion propulsion system in interplanetary space

Originally designed to test a dozen new technologies including the use of an ion engine for spacecraft propulsion, Deep Space 1 far outstripped its primary mission goals by also successfully flying by the asteroid 9969 Braille and comet Borrelly. The flybys produced what are still considered some of the best images and data ever collected from an up-close encounter with an asteroid or comet.

The success of Deep Space 1 set the stage for future ion-propelled spacecraft missions, especially those making the technically difficult journey to asteroids or comets, such as NASA’s Dawn mission.

July 29, 1999: Having completed its technology testing within the first couple months after launch, Deep Space 1 makes a bonus flyby of the asteroid 9969 Braille, flying within about 17 miles (27 kilometers) of the object.

November 1999: While embarking on a new journey to comet Borrelly, the spacecraft’s star tracker used for determining its orientation in the zero gravity of space fails, nearly ending Deep Space 1’s extended mission.

June 2000: Engineers develop a new way to operate the Deep Space 1 spacecraft after the potentially mission-ending failure of its star tracker. Software is radioed to the probe using the camera on board to serve as a replacement navigational tool. The operation marks one of the most successful robotic space rescues in the history of space exploration.

September 2001: Deep Space 1 approaches comet Borrelly, using all of its advanced science instruments to collect important data on the comet’s environment and its icy, rocky nucleus. Despite the challenges faced by the spacecraft, it’s able to snap the best up-close pictures of a comet to-date.

While the particles expelled from an ion drive travel much faster than the gases from a conventional rocket, they are not massive enough to provide sufficient thrust. Rockets such as the Space Shuttle can produce millions of pounds of thrust at lift-off, whereas, to begin with, an ion drive can only produce around 20-thousandths of a pound of thrust. This is not enough force to escape Earth’s gravitational pull. Crafts with ion drives have to be carried into space by a conventional rocket, but once they have left Earth’s orbit, their velocity continues to increase, until they reach much faster speeds than rockets. Ion drives are also much more efficient, using only 80kg (1761bs) of xenon in a two-year mission.

Chemical rockets were the powerhouses of the space age. But after 90 years of development, further engine refinements aren’t expected to lead to major improvements in terms of thrust (these rockets are fundamentally limited by the energy held in chemical bonds).

Litchfield argues that research in chemical rocketry should still constitute the major effort of NASA research, especially towards generating fuel at the destination planet, rather than carrying it all on board. For example, those on Mars might split ice from the polar caps into hydrogen and oxygen to use as rocket fuel. These engines use electrical energy to create super-heated plasma and fire it through a supersonic nozzle to generate thrust.

These kinds of engines have been used in Russian satellites since the 1970s and by Lockheed Martin A2100 satellites, using hydrazine as fuel. These engines are efficient, but the thrust they generate is extremely low, meaning their only likely use will be to orient satellites in orbit.

Now we’re getting to the futuristic stuff. The ion drive engine is a thruster where molecules of an unreactive fuel, such as xenon, are given a positive or negative charge (“ionised”) and accelerated by an electric field to be shot out the back.

The thrust is incredibly low, equivalent to the pressure exerted by a sheet of paper on the palm of your hand, so an ion engine is very slow to pick up speed. But over a long-range mission, it can deliver 10 times as much thrust per kilogram of fuel as a chemical rocket.

The Dawn space probe, currently in orbit around dwarf planet Ceres (and responsible for the first striking photos of mysterious bright spots), used its ion drive to become the first spacecraft to enter and leave the orbits of multiple celestial bodies.