Artist's impression of a solar sail. Image credit: NASA
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Last week we talked about rockets. How they work and their limitations. This week we’re going to look at the future of propulsion systems. From the ion engines that are already working to explore the Solar System to the prototype solar sails to futuristic technologies like magnetic sails, and bussard ramjets. This is how we’ll travel to other stars.
The space-time bubble. Unfortunately, quantum physics may have the final word (Michael Alcubierre)
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Standard in almost every Star Trek episode are warp drives and cloaking devices. But in reality these science fiction gadgets defy the laws of physics. Or do they? Different scientists have been working on developing these two devices and they say they are getting closer to actually creating working prototypes. While warp drive won’t be available anytime soon, scientists are gaining a better understanding of how faster-than-light speed could possibly be achieved. And as for cloaking devices, don’t look now, but researchers recently cloaked three-dimensional objects using specially engineered materials that redirects light around objects.
Previously, scientists at the University of California, Berkley were only able to cloak very thin, two dimensional objects. But now, using meta-materials, which are mixtures of metal and circuit board materials such as ceramic, Teflon or fiber composite, scientists have deflected light waves around an object, like water flowing around a smooth rock in a stream. Objects are visible because they scatter the light that strikes them, reflecting some of it back to the eye. But the meta-materials would ward off light, radar or other waves. In effect, it would be a type of optical camouflage.
The research group, led by Xiang Zhang say they are a step closer to being able to render people and objects invisible. Their findings will be released later this week in the journals Nature and Science. The path that light rays would take through a theoretical cloaking device. Credit: John Pendry
Another scientist and one of the leaders in cloaking research is John Pendry, a theoretical physicist at Imperial College, London. It was he who first worked out how a cloak could be built in theory, and then he helped build the first working cloak. Pendry recently submitted an abstract that discusses what he says is a new type of cloak, one that gives all cloaked objects the appearance of a flat conducting sheet. Pendry says this type of cloak has the advantage in that nothing remarkable is required to create the cloak. Pendry said the device could be “made isotropic. It makes broadband cloaking in the optical frequencies one step closer.” This type of cloak seemingly creates a mirage to render an object invisible to the eye. Pendry’s own website says information on his new cloak will be available soon.
While cloaking devices would have military applications, a group of scientists researching warp drives say they just want to have the ability to travel to Earth-like exoplanets, like Gliese 581c to better understand the origin and development of life. “The only way we could realistically visit these worlds in time-frames on the order of a human lifespan would be to develop what has been popularly termed a `warp drive,'” said researchers Gerald Cleaver and Richard Obousy from Baylor University in Texas.
Their work expands on research done by theoretical physicist Michael Alcubierre from the University of Mexico, who in 1994 demonstrated space could be made to move around a spacecraft by `stretching’ space so that space itself would expand behind a hypothetical spacecraft, while contracting in front of the craft, creating the effect of motion. So, the ship itself doesn’t move, but space moves around it.
Their new research tries to take advantage of advances in understanding dark energy and why our universe is ever-expanding in every direction. Comprehending that might give us a leg up in being able to generate an asymmetric bubble around a spacecraft. “If we can understand why spacetime is already expanding, we may be able to use this knowledge to artificially generate an expansion (and contraction) of spacetime,” said Cleaver and Obousy in their abstract.
They propose manipulating the 11th dimension, a special theoretical part of an offshoot of string theory called the “m-theory” to create a bubble of dark energy by shrinking the 11th dimension in front of the ship and expanding it behind.
Obviously, this is highly theoretical, but if it leads researchers to a better understanding of dark energy, so much the better.
There’s one hitch, however. Cleaver and Obousy calculated that the energy needed to distort the space around a spacecraft-sized object is about 10^45 Joules or the total energy of an object the size of Jupiter if all its mass were converted into energy.
This creates a chicken and the egg type of conundrum. Which comes first: understanding dark energy or having the ability to create huge amounts of energy?
But Cleaver and Obousy are upbeat about it all. “This is a hypothetical propulsion device that could theoretically circumvent the traditional limitations of special relativity which restricts spacecraft to sub-light velocities. Any breakthrough in this field would revolutionize space exploration and open the doorway to interstellar travel.”
An early parachute drop test for the Constellation Project (NASA)
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At the end of last month, the Orion crew module and the Ares I rocket parachute systems underwent a series of drop tests. The “drogue parachute” that will gently slow the descent of the spent first-stage motor of the Ares vehicle appeared to function as expected over the Arizona skies. However, an Orion test failed, “programmer parachute” failing to correct the orientation of the test crew module, allowing the module to drop through the sky upside-down. The programmer parachute is intended to inflate before the main three parachutes are deployed to bring the re-entering Orion astronauts to land safely. This news has come from an internal memo referring to the Orion test drop back on July 31st; the successful Ares I drogue parachute drop was carried out on July 24th. So what went wrong with the Orion test-drop?
NASA engineers are continuing a series of parachute tests on Orion and Ares. The first parachute system to be employed in any given launch will be the Ares parachute recovery system (assuming the emergency jettison motor isn’t fired before then). At approximately 126 seconds into flight and at an altitude of 189,000 feet (58,000 m), the first Ares I stage will separate, letting the spent booster drop through the atmosphere. To ensure the engine can be re-used by subsequent Constellation launches, the booster’s nose cap will be jettisoned at 15,740 feet (4800 m), releasing a small pilot parachute, dragging a larger drogue parachute out to slow down the rapidly falling first stage.
The Ares I components (NASA)
The drogue is smaller than a conventional parachute and it is intended to slow the booster from 402 mph (647 km/hr) to 210 m/hr (338 km/hr), positioning the cylinder vertically. Only when this slowdown is achieved that the main three cluster of parachutes can be deployed to complete the descent and plunge into the Atlantic Ocean for retrieval.
It would appear that the essential drogue testing of the first stage Ares I booster worked flawlessly when tested by NASA at the U.S. Army’s Yuma Proving Ground near Yuma, Arizona on July 24th. The next drogue test is scheduled for October.
However, during the July 31st Orion parachute test-run, there was a slight technical hitch that gave the Parachute Test Vehicle (PTV) a violent spin and then thud into the ground. The “programmer” parachute is intended to “right” the orientation of the re-entering crew module as it descends, an essential task before the drogue parachutes can be deployed to rapidly slow the module (in a similar way to the Ares I system). Unfortunately, during this PTV test-drop, problems arose very quickly. As soon as the programmer parachute was deployed, it failed to inflate and therefore did not cause any drag. This happened as the programmer parachute was being buffeted by the turbulence in the wake of the PTV and stabilization parachutes. The PTV was therefore allowed to fall ungracefully, upside-down.
The Orion crew module (HowStuffWorks.com)
Continuing to drop, the programmer and stabilization parachutes were jettisoned (having not done their job very well), and drogue parachutes were deployed. As the PTV was falling out of control, the drogue parachutes were put under immediate strain and wrapped around the PTV, dynamic pressure causing the drogue to be cut away.
Having suffered some major whiplash, the PTV’s main bag retention system was damaged and failed. Continuing to fall, the main parachutes were deployed, two were ripped from the vehicle, forcing the PTV to hit the ground with only one parachute open. There are no details as to what damage was caused by this failed test, but I think we can assume the PTV’s bodywork will be dented (and I wonder if human cadavers were used on this particular drop. If they were, I wouldn’t want to be the first engineer on the scene!).
Although an obvious set-back for the Orion parachute system, the NASA memo highlights that it was a “test technique failure” and not a failure of the technology itself. Regardless, I am sure this issue will be ironed out soon enough as the Constellation Program continues to push ahead with development…
The Vasimir experiment (Ad Astra Rocket Corporation)
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NASA Administrator Michael Griffin has announced his intentions to send an advanced spaceship propulsion prototype to the International Space Station for advanced testing. The Variable Specific Impulse Magnetoplasma Rocket (Vasimir) is currently in an experimental phase, but Griffin hopes that a scale model will be ready for one of the remaining Shuttle-ISS missions before 2010. The Vasimir concept bridges the gap between conventional (fuel hungry, high thrust) rockets and economical (fuel efficient, low-thrust) ion engines. Vasimir achieves this by using an ingenious method of ionizing and heating a neutral gas fuel…
It sounds like an idea from the “let’s do something useful with the Space Station” department in response to recent criticism about the quality of science that is being carried out on the $100 billion orbiting outpost. Michael Griffin, attended the July 29th AirVenture show in Oshkosh and was asked about the status of NASA’s advanced space propulsion research. In response he outlined plans to begin testing the Vasimir on board the ISS within the coming years. This possibly means that Vasimir will undergo vacuum testing on the outside of the station. (NOTE: This is not a propulsion device for the Space Station itself, it will remain in Earth orbit for the rest of its years, regardless of the optimistic idea that it could become an interplanetary space vehicle.)
Vasimir on the test-bed (Ad Astra Rocket Corporation)
The Vasimir uses a gas, like hydrogen, as a fuel. When injected, the engine turns the hydrogen into a plasma (a highly ionized state of matter). Through the use of intense radio signals emitted from powerful superconducting magnets, the engine is able to produce this plasma and energize it. The hot plasma is then focused and directed by a magnetic nozzle which creates thrust. The Vasimir turns out to be a very efficient way to get optimal thrust from minimal fuel (a quantity in rocket science known as “specific impulse”) through ionizing a fuel and accelerating it with a magnetic field. Such a technology is far more efficient than conventional rockets (as it uses less fuel) and provides more thrust than ion engines.
At the moment, the Vasimir looks as if it is in a “test-bed” phase of development, resembling something too large and unwieldy to be put into space, but Griffin is hoping a scale model may me taken to the ISS, possibly by one of the remaining Shuttle flights before 2010.
The engine itself is being developed by the Ad Astra Rocket Corporation and NASA signed a co-operation agreement with the company in 2006 in the hope of working on large-scale testing of rocket products. Naturally, Vasimir testing on board the Space Station would be of tremendous value in the research of this technology (but there is no mention that the Vasimir could be used as an ISS propulsion device, shame really).
To move around in space, you need some kind of propulsion system. And for now, that means rockets. Let’s learn the underlying science of rockets, and how they work. And learn why a rocket will never let us reach the speed of light.
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In a defiant message to his employees after Saturday’s Falcon 1 loss, Elon Musk, founder and CEO of Space Exploration Technologies Corporation (SpaceX) said, “I will never give up and I mean never.” This statement, along with some positive details about what went right with the launch of the 47 tonne rocket, he outlined his plans for the future direction of the corporation. Interestingly, he also overviewed what went wrong with Flight 3 as it ascended through the atmosphere. According to Musk, the first Merlin 1C rocket stage performed perfectly, but the problem occurred during stage separation, causing the first and second stages to be held together for too long. An inquiry is under way…
Watching the live video feed from the Kwajalein Atoll in the South Pacific a few hours ago was a frustrating experience. As reported by another reader of the Universe Today, the feed was low quality and pretty choppy, especially during the T-10 second countdown. But I was very excited all the same to see the Falcon 1 Merlin 1C engine light up (for two frames), blast out a puff of exhaust… only for it to stop and abort. This was at 8pm PST. According to Max Vozoff, SpaceX mission manager, some parameter was 1% out of “normal” operating limits so the Falcon 1 rocket shut down. Quickly, engineers were on the scene evaluating what had gone wrong. In an amazingly quick turn around, Vozoff had announced the ground crews were good to go and a new countdown would commence.
Within the hour, we were back to T-10 seconds and the Merlin engine blasted to life once more, this time with a lot more conviction. Before the female voice at mission control could say “two, one,” Falcon 1 had blasted off and powered away from the launchpad. It was an awesome sight (even if the video had become more choppy than before, probably due to online demand). The delight at mission control could be heard and the atmosphere was alight with enthusiasm.
But during the flight, 35 km off the ground and 140 seconds later, the video stream was suddenly cut. According to some viewers there was some anomalous rotation oscillations. Soon, we were back at mission control looking at the concerned faces of Max Vozoff and Emily Shanklin. Vozoff was listening to instructions from the flight controllers and eventually composed himself to say the following statement:
“We are hearing from the launch control center that there has been an anomaly on the vehicle. We don’t have any information about what that anomaly is at this time. We will, of course, be doing an assessment of the situation and providing information as soon as it becomes available.” – Max Vozoff.
The anomaly, according to Musk, was with the stage separation not occurring when it should. The Merlin 1C engine in the first stage (which was completely designed from scratch by SpaceX) performed “picture perfect,” but the second stage rocket wasn’t able to prove itself as the launch had to be aborted. At this time, I am uncertain whether Falcon 1 was remotely destroyed or whether it was allowed to plunge into the ocean (although the latter option seems unlikely). We’ll know at a later date as to the details of this anomaly.
For now, our thoughts go out to the SpaceX scientists and engineers who have exhaustively put all their efforts into this third flight of the rocket (the previous two test flights also failed to varying degrees). For now, I’ll leave you with the full text of Elon Musk’s statement to his employees:
The full text of Saturday’s statement:
Plan Going Forward
It was obviously a big disappointment not to reach orbit on this flight [Falcon 1, Flight 3]. On the plus side, the flight of our first stage, with the new Merlin 1C engine that will be used in Falcon 9, was picture perfect. Unfortunately, a problem occurred with stage separation, causing the stages to be held together. This is under investigation and I will send out a note as soon as we understand exactly what happened.
The most important message I’d like to send right now is that SpaceX will not skip a beat in execution going forward. We have flight four of Falcon 1 almost ready for flight and flight five right behind that. I have also given the go ahead to begin fabrication of flight six. Falcon 9 development will also continue unabated, taking into account the lessons learned with Falcon 1. We have made great progress this past week with the successful nine engine firing.
As a precautionary measure to guard against the possibility of flight 3 not reaching orbit, SpaceX recently accepted a significant investment. Combined with our existing cash reserves, that ensures we will have more than sufficient funding on hand to continue launching Falcon 1 and develop Falcon 9 and Dragon. There should be absolutely zero question that SpaceX will prevail in reaching orbit and demonstrating reliable space transport. For my part, I will never give up and I mean never.
Thanks for your hard work and now on to flight four.
The SpaceX Falcon 1 rocket is being prepped for launch (SpaceX)
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It was announced that the private space company, SpaceX, had set today as their launch window for their Falcon 1 rocket system to orbit the Earth. The press release reads:
Space Exploration Technologies Corp. (SpaceX) has scheduled the launch of the Falcon 1 Flight 3 mission for Saturday, August 2nd. The launch window will open at 4:00 p.m. (PDT) / 7:00 p.m. (EDT) and remain open for five hours. If launch is delayed for any reason, SpaceX has range availability to resume countdown through August 5.
Lift-off of the vehicle will occur from SpaceX’s Falcon 1 launch site at the Kwajalein Atoll, about 2500 miles southwest of Hawaii. Falcon 1 launch facilities are situated on Omelek Island, part of the Reagan Test Site (RTS) at United States Army Kwajalein Atoll (USAKA) in the Central Pacific.
Update:Approximately 140 seconds into the flight, Falcon 1 suffered an undisclosed anomaly. The vehicle had just switched to inertial guidance mode. At the last check, it was travelling at a velocity of 1050 m/s at an altitude of 35 km. It is assumed Falcon 1 is lost. Webcast has now been closed.
The Falcon 1 rocket system
The California-based space systems company was founded by Elon Musk in 2002 to provide a commercial alternative to launching payloads into space. SpaceX is currently carrying out a series of test flights of their Falcon 1 rocket, which is a two-stage, liquid oxygen and kerosene fuelled launch vehicle. Falcon 1 has already undergone two test flights, one in March 2006 and the second was in March 2007. The first launch failed only 29 seconds into the flight after the main engine failed, causing the loss of the rocket. The 2007 launch had more success and reached a velocity of 11,000 miles/hour, but unfortunately did not attain orbital velocity. It lost control at around 300 miles altitude and was lost. Today marks the third test flight, and hopes are high that lessons have been learnt and Falcon 1 will be successfully inserted into a stable low Earth orbit.
The Falcon 1 first stage is powered by a single Merlin 1C Regenerative engine that SpaceX developed. This is the first time the Merlin 1C will be used. The second stage is powered by a single Kestrel engine (again, developed by the company).
If successful, this third test flight will be celebrated as the first new orbital rocket to be developed and launched for over ten years; it will also be the first new US hydrocarbon engine for an orbital booster to be flown in 40 years and only the second US engine of any kind in more than a quarter of a century. What makes this historic endeavour even more impressive, is that once Falcon 1 reaches orbit (hopefully within today’s launch window), SpaceX will be the world’s first private company to develop an operational liquid fuel rocket to orbit the Earth
UPDATE (8:43pm): The webcast presenters announced an “anomaly” during Falcon 1’s ascent. We await news about this event, but it is assumed Falcon 1 is lost.
More information from today’s press release: SpaceX
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It looks like a US Air Force robotic orbiter will push back the planned launch date of NASA’s Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS). The double satellite launch, originally set for November this year, will now take place sometime early 2009. They will make way for the test flight of the orbital Boeing X-37B spaceplane, commandeering the Atlas V rocket flight originally intended for NASA. According to the Air Force, the November X-37B test flight will be a study into “risk reduction, experimentation, and operational concept development for reusable space vehicle technologies.” (There might also be some urgency due to the Shuttle decommissioning in 2010…)
The X-40 undergoing a test flight in 1998 (NASA)
The X-37B’s predecessors have undergone exhaustive testing. Based at Edwards Air Force Base, California, the US military has been testing automated spaceplanes for many years. NASA has also been heavily involved in the program. Originally tasked with developing a Space Manoeuvre Vehicle (SMV) that could either be launched by the Shuttle or by rocket, the US Air Force wanted an automated orbital vehicle that could carry out a multitude of tasks in space for up to a year. The X-40 design evolved and by 1998, the vehicle was being dropped from helicopters and allowed to land like a conventional aircraft (automatically). The X-40 military program was then passed to NASA to use as the basis of the X-37 program. After a long period of development, the X-37A was used in conjunction with Scaled Composites WhiteKnightOne (pictured below).
The X-37A carried by WhiteKnightOne in 2005 (Alan Radecki)
Now the brand new Boeing X-37B is ready to be launched to begin its first automated orbital operations, re-enter and land conventionally. The Atlas V rocket will blast off from Cape Canaveral and the X-37B will hopefully land on schedule at Edwards Air Force Base. The X-37B is 27 ft (8 m) long with a 15 ft (4.5 m) wingspan and resembles a blindfolded mini-Shuttle (it really does! See the picture at the top of the article).
Although there will be a lot of anticipation for the X-37B test flight, it is a shame for the lunar mission scientists who are currently preparing the LRO and LCROSS for their trip to the Moon. The LRO’s objective is to orbit the Moon, analysing the surface to aid future manned missions. LCROSS has something a little more spectacular planned; it will create two impact plumes during it’s kamikaze mission in aid of detecting present water in the lunar rock.
Sir Richard Branson and designer Burt Rutan walk aside the Virgin Mothership "Eve" (VMS EVE) in Mojave, CA. on the eve of its official rollout on July 28, 2008 (Virgin Galactic)
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Early this morning in the Californian Mojave Desert, Richard Branson and Burt Rutan unveiled the completed Virgin Galactic Mothership “Eve,” the first time this highly secretive project has seen the light of day. This is a significant moment for both Virgin Galactic and Scaled Composites, the company that built Eve, as it shows space tourism is only a heartbeat away. Now we await the completion of SpaceShipTwo that is expected to begin test flights with Eve by 2009.
The rollout represents another major milestone in Virgin Galactic’s quest to launch the world’s first private, environmentally benign, space access system for people, payload and science. – Virgin Galactic rollout press release (July 28th).
Eve is towed onto the airstrip at Mojave Air and Space Port (Virgin Galactic)
Eve is a large aircraft, with a wing span of 140 feet (42.7 meters), constructed from the world’s longest single carbon composite aviation component ever manufactured. Eve is basically a flying wing with two fuselages plus four efficient Pratt and Whitney PW308A engines attached. During operational flight sometime late 2009 or early 2010, it is hoped the mother ship will fly four times a day, carrying SpaceShipTwo up to 50,000 ft (9.5 miles) high. Once the aircraft reaches 50,000 ft, the spaceship will detach and ignite its rocket engines, blasting six fee-paying space tourists and two pilots to an altitude of around 360,000 feet (68 miles). This is considered to be the edge of space, allowing the SpaceShipTwo occupants five minutes of weightlessness before starting their journey back to Earth.
The cockpit of Eve (Virgin Galactic)
Today’s rollout onto the airstrip of Mojave Air and Space Port was witnessed by government officials, business partners and the future Virgin Galactic space tourists. Eve, named in honour of Branson’s mother, is the first WhiteKnightTwo aircraft of two that are on order with Scaled Composites. A total of five SpaceShipTwo’s are expected to complete the fleet.
Eve in the hangar (Virgin Galactic)
Today’s press release also states: “Driven by a demanding performance specification set by Virgin Galactic, WhiteKnightTwo has a unique heavy lift, high altitude capability and an open architecture driven design which provides for maximum versatility in the weight, mass and volume of its payload potential. It has the power, strength and maneuverability to provide for pre space-flight, positive G force and zero G astronaut training as well as a lift capability which is over 30% greater than that represented by a fully crewed SpaceShipTwo.”
Artist impression of Eve dropping SpaceShipTwo at an altitude of 50,000 ft (Virgin Galactic)
Fights with Virgin Galactic currently cost a hefty $200,000, but this ticket price is likely to fall in time. Over 200 tickets have already been sold. Initially, the company is offering sub-orbital space flights, but eventually Branson wants to push one stage further and begin offering tourists orbital space flight. The entrepreneur has even more optimistic ideas for his future space tourist empire including sending people into space during an aurora, space hotels and trips to the Moon. To be honest, I’d be excited to try out that rocket ride into space after the leisurely flight attached to WhiteKnightTwo…
Successful test-firing of Orion's jettison engines (Aerojet)
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It looks like the hardware is gradually slotting into place for the development of the Orion capsule in NASA’s Constellation Program. On July 17th, the ultimate “ejection seat” was tested by NASA and rocket contractor Aerojet: The Orion jettison motor. Should there be an emergency during Ares rocket/Orion capsule during launch, the Orion capsule will have the capability to eject (whether it is on the launchpad or travelling through the atmosphere), ensuring the safety of the crew. This is the first safety measure of its kind, so a successful engine test can only help to boost confidence in the technology behind Orion…
Although there are concerns for the Constellation Program funding and technology-wise, there is good news coming from the development of NASA’s new Orion crew module. The first full-scale test firing of the jettison motor was successful, boosting confidence in the new safety system the capsule will have installed. Later this year, a full-scale “Pad Abort-1” test is scheduled in the New Mexico desert, where a mock Orion will be blasted clear of a model launchpad (up to a mile in altitude) to test the effectiveness of the system. Tests are already under way to deduce whether a dry or wet touch-down will be carried out by the Orion capsule using cadavers (human corpses) as crash-test dummies.
The jettison motor was tested at the Astrojet facility in Sacramento, California, which marks the start of a series of developmental tests before the finished article is integrated into the mock Orion module to begin the New Mexico tests. During last weeks test firing, engineers were testing acoustic, vibration and shock effects on the engines. It appears everything ran smoothly, indicating the jettison system is close to system-level demonstration.
This is a critical stage in the development of Orion. Since the Columbia disaster in 2003, NASA has felt pressure to ensure the safety of their astronauts. Although strict guidelines are in place, space travel remains a risky business where tough decisions need to be made. Installing an Orion jettison system will be a huge piece of mind for mission controllers and Constellation astronauts should there be launch complications on the pad or as Ares powers through the atmosphere.
