There’s a famous line from Shakespeare’s Hamlet that says “There are more things in heaven and Earth, Horatio, than are dreamt of in your philosophy,” and the same now holds true for brave new worlds for humans to explore.
This result was published earlier this week courtesy of the NASA/JPL Near-Earth Program Office. The study found that the number of possible asteroid targets for human exploration has now doubled from the 666 known in the first study, completed in late 2010.
This information comes from NHATS, which stands for the Near Earth Object Human Spaceflight Accessible Targets Study. Yes, it’s an acronym containing acronyms. NHATS is an automated system based out of Greenbelt, Maryland which monitors and periodically updates its list of potential target candidates for accessibility. The NHATS system data is readily accessible to the public online, and as of February 11th 2015, 1346 NHATS compliant asteroids are known.
This is the Holy Grail for the future of manned spaceflight, and will represent a good stepping stone (bad pun intended) for future crewed missions to Mars. Several hundred NHATS asteroids require less time and energy to reach than the Red Planet, and a few dozen even require less energy to reach than it does to enter lunar orbit.
Relative delta-V and return velocity is crucial. Apollo astronauts were subject to a blistering 11 kilometre per second reentry velocity on their return from the Moon, and future asteroid missions would be subject to the same style of trajectory on return to Earth from a solar orbit.
The test of the Orion heat shield on reentry during last year’s EFT-1 flight was a step in this direction, and the next test will be an uncrewed launch atop an SLS rocket in September 2018. If all goes according to schedule — and NASA can successfully weather the ever-shifting political winds of multiple future changes of administration — expect to see astronauts exploring an NHATS asteroid placed in lunar orbit sometime around late 2023.
I know. “When I was a kid back in the 70’s…” we expected to be vacationing on Callisto by 2015, as well.
Brent Barbee at NASA’s Goddard Space Flight Center designed the automated NHATS system. It pulls data from a source that many comet and asteroid hunters are familiar with: JPL’s Small Bodies Database. The NHATS system then makes trajectory calculations and patches in conical solutions for possible spacecraft trajectories and actually gives potential launch window dates for future missions. Seriously, its fun to play with… you can even tailor and filter these by target dates versus maximum velocity constraints and the length of stays.
The first discovered NHATS-compliant NEO was 2.3 kilometre 1943 Anteros way back in 1973, and famous alumni on the NHATS list also include 10 metre asteroid 2011 MD, which passed 12,000 kilometres from the Earth on June 27th, 2011. 2011 MD is on NASA’s short list of asteroids ideal for human exploration. Another famous asteroid on the NHATS list is 99942 Apophis which — triskaidekaphobics take note — will safely miss the Earth by 31,300 kilometres on Friday the 13th, April 2029. More are added every day, and the growing curve of discoveries also closely mirrors the rise of automated all-sky surveys such as LINEAR, PanSTARRS and the Catalina Sky Survey, though dedicated amateurs do get in on the act occasionally as well.
To date, over 12,000 NEA asteroids are now known, and you can expect future surveys such as the Large Synoptic Survey Telescope set to see first light in 2021 to add to their ranks. The Sentinel space telescope set to launch in 2017 will also boost the known number of NEOs as it covers our sunward blind spot from an orbit interior to the Earth’s. Remember Chelyabinsk? That could actually be a great rallying cry for Sentinel’s cause, as the asteroid came at the Earth from a sunward direction and avoided the sky sweeping robotic eyes of astronomers.
Sometimes, NEOs turn out to be returning space junk from the early Space Age (a low relative velocity and low orbital inclination is often a dead giveaway). Earth has also been known to capture an NEO as an occasional temporary second Moon, as occurred in 2006 in the case of asteroid 2006 RH120.
But beyond just creating a database, the NHATS system also presents key opportunities for astronomers to perform follow-up observations of NEO asteroids, which is vital for precisely characterizing their orbits. Two future missions are also planned to return samples from NHATS asteroids: Hayabusa 2, which launched on December 3rd 2014 headed for asteroid 1999 JU3 in July 2018, and the OSIRIS-REx mission, set to launch in late 2016 headed for asteroid 101955 Bennu in 2018.
NHATS is providing a crucial target list for that day when first human footfall on an asteroid occurs… or should we say docking?
MOAR rockets! As a followup to our recent post about the Rockets of the World (to scale), here’s another graphic posted on imgur, created by Alex Brown. While the earlier graphic only included rockets that had flown, this one has rockets that are also in development, such as the SLS, Falcon Heavy and the Long March 9. It’s also a great look back at the history of rocket development, including the V-2 ballistic, England’s Black Arrow and Korolyov’v wide-body Sputnik. All are shown to scale, as compared with an average human being.
As noted, this graphic is as of the present, February 2015.
Here’s a collection of a few of the newest sunrises, auroras, landscapes, nightlights, and more snapshots from the multinational crew of six astronauts and cosmonauts living and working aboard the ISS orbiting some 250 miles (400 kilometers) overhead.
And don’t forget that at sunset tonight (Feb. 8), a SpaceXFalcon 9 rocket is due to blastoff at 6:10 p.m., EST, if all goes well carrying the DSCOVR space weather satellite about a million miles (1.5 million kilometers) away to the L1 Lagrange point.
The Falcon 9 will blastoff from Cape Canaveral, Florida, pictured below:
Tens of millions of you are included in the lead sunrise photo of the U.S. East Coast – taken by ESA astronaut Samantha Cristoforetti perched aboard the orbiting lab complex.
And here’s a “speechless sunrise” taken today by NASA astronaut Terry Virts. We agree!
The current six person crew includes astronauts and cosmonauts from three nations; America, Russia and Italy including four men and two women serving aboard the massive orbiting lab complex.
They comprise Expedition 42 Commander Barry “Butch” Wilmore and Terry Virts from NASA, Samantha Cristoforetti from the European Space Agency (ESA) and cosmonauts Aleksandr Samokutyayev, Yelena Serova, and Anton Shkaplerov from Russia.
L+72/73: Logbook. Wow, this has been a busy week! But we can still catch up a little bit… ESA astronaut Samantha Cristoforetti
….https://plus.google.com/app/basic/stream/z12iczzoqovhfdo2z23odnbwmz3cir0ox04?cbp=1hmsp4t51xmr3&sview=27&cid=5&soc-app=115&soc-platform=1&spath=%2Fapp%2Fbasic%2F%2BSamanthaCristoforetti%2Fposts …
Soyuz- everyone’s ride to space and back!
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
Sometimes, it seems to be a cosmic misfortune that we only get to view the universe from a singular vantage point.
Take the example of our single natural satellite. As the Moon waxes and wanes through its cycle of phases, we see the familiar face of the lunar nearside. This holds true from the day we’re born until the day we die. The Romans and Paleolithic man saw that same face, and until less than a century ago, it was anyone’s guess as to just what was on the other side.
Enter the Space Age and the possibility to finally get a peek at the universe from different perspective via our robotic ambassadors. This week, the folks over at NASA’s Scientific Visualization Studio released a unique video simulation that utilized data from NASA’s Lunar Reconnaissance Orbiter to give us a view unseen from Earth. This perspective shows just what the phases of the Moon would look like from the vantage point of the lunar farside:
You can see the Moon going through the synodic 29.5 day period a familiar phases, albeit with an unfamiliar face. Note that the Sun zips by, as the lunar farside wanes towards New. And in the background, the Earth can be seen, presenting an identical phase and tracing out a lazy figure eight as it appears and disappears behind the lunar limb.
What’s with the lunar-planetary game of peek-a-boo? Well, the point of view for the video assumes that your looking at down at the lunar farside from a stationary point above the Moon. Note that the disk of the Moon stays fixed in place. The Moon actually ‘rocks’ or nods back and forth and side-to-side in motions referred to as libration and nutation, and you’re seeing these expressed via the motion of the Earth in the video. This assures that we actually get a peek over the lunar limb and see a foreshadowed extra bit of the lunar farside, with grand 59% of the lunar surface visible from the Earth. Such is the wacky motion of our Moon, which gave early astronomers an excellent crash course in celestial mechanics 101.
Now, to dispel some commonly overheard lunar myths:
Myth #1: The moon doesn’t rotate. Yes, it’s tidally locked from our perspective, meaning that it keeps one face turned Earthward. But it does turn on its axis in lockstep as it does so once every 27.3 days, known as a sidereal month.
Myth #2: The Farside vs. the Darkside. (Cue Pink Floyd) We do in fact see the dark or nighttime side of the Moon just as much as the daytime side. Despite popular culture, the farside is only synonymous with the darkside of the Moon during Full phase.
Humanity got its first glimpse of the lunar farside in 1959, when the Soviet Union’s Luna 3 spacecraft looked back as it flew past the Moon and beamed us the first blurry image. The Russians got there first, which is why the lunar farside now possesses names for features such as the “Mare Moscoviense”.
Think we’ve explored the Moon? Thus far, no mission – crewed or otherwise – has landed on the lunar farside. The Apollo missions were restricted to nearside landing sites at low latitudes with direct line of sight communication with the Earth. The same goes for the lunar poles: the Moon is still a place begging for further exploration.
Why go to the lunar farside? Well, it would be a great place to do some radio astronomy, as you have the bulk of the Moon behind you to shield your sensitive searches from the now radio noisy Earth. Sure, the dilemmas of living on the lunar farside might forever outweigh the benefits, and abrasive lunar dust will definitely be a challenge to lunar living… perhaps an orbiting radio astronomy observatory in a Lissajous orbit at the L2 point would be a better bet?
And exploration of the Moon continues. Earlier this week, the LRO team released a finding suggesting that surface hydrogen may be more abundant on the poleward facing slopes of craters that litter the lunar south pole region. Locating caches of lunar ice in permanently shadowed craters will be key to a ‘living off of the land’ approach for future lunar colonists… and then there’s the idea to harvest helium-3 for nuclear fusion (remember the movie Moon?) that’s still science fiction… for now.
Perhaps the Moonbase Alpha of Space: 1999 never came to pass… but there’s always 2029!
The purpose of the pair of abort tests is to demonstrate a crew escape capability to save the astronauts’ lives in case of a rocket failure, starting from the launch pad and going all the way to orbit.
Both SpaceX and Boeing plan to launch the first manned test flights to the ISS with their respective transports in 2017.
During the Sept. 16, 2014, news briefing at the Kennedy Space Center, NASA Administrator Charles Bolden announced that contracts worth a total of $6.8 Billion were awarded to SpaceX to build the manned Dragon V2 and to Boeing to build the manned CST-100.
The first abort test involving the pad abort test is currently slated to take place soon from the company’s launch pad on Cape Canaveral Air Force Station in Florida, according to Gwynne Shotwell, president of SpaceX.
“First up is a pad abort in about a month,” said Shotwell during a media briefing last week at NASA’s Johnson Space Center in Houston, Texas.
SpaceX engineers have been building the pad abort test vehicle for the unmanned test for more than a year at their headquarters in Hawthorne, California.
Dragon V2 builds on and significantly upgrades the technology for the initial cargo version of the Dragon which has successfully flown five operational resupply missions to the ISS.
“It took us quite a while to get there, but there’s a lot of great technology and innovations in that pad abort vehicle,” noted Shotwell.
The pad abort demonstration will test the ability of a set of eight SuperDraco engines built into the side walls of the crew Dragon to pull the vehicle away from the launch pad in a simulated emergency.
The SuperDraco engines are located in four jet packs around the base. Each engine can produce up to 120,000 pounds of axial thrust to carry astronauts to safety, according to a SpaceX description.
Here is a SpaceX video of SuperDraco’s being hot fire tested in Texas:
Video caption: Full functionality of Crew Dragon’s SuperDraco jetpacks demonstrated with hotfire test in McGregor, TX. Credit: SpaceX
For the purpose of this test, the crew Dragon will sit on top of a facsimile of the unpressurized trunk portion of the Dragon. It will not be loaded on top of a Falcon 9 rocket for the pad abort test.
The second abort test involves a high altitude abort test launching atop a SpaceX Falcon 9 rocket from Vandenberg Air Force Base in California.
“An in-flight abort test [follows] later this year,” said Shotwell.
“The Integrated launch abort system is critically important to us. We think it gives incredible safety features for a full abort all the way through ascent.”
“It does also allow us the ultimate goal of fully propulsive landing.”
Both tests were originally scheduled for 2014 as part of the firm’s prior CCiCAP development phase contract with NASA, SpaceX CEO Elon Musk told me in late 2013.
“Assuming all goes well, we expect to conduct [up to] two Dragon abort tests next year in 2014,” Musk explained.
Last year, NASA granted SpaceX an extension into 2015 for both tests under SpaceX’s CCiCAP milestones.
The SpaceX Dragon V2 will launch atop a human rated Falcon 9 v1.1 rocket from Space Launch Complex 40 at Cape Canaveral.
“We understand the incredible responsibility we’ve been given to carry crew. We should fly over 50 Falcon 9’s before crewed flight,” said Shotwell.
To accomplish the first manned test flight to the ISS by 2017, the US Congress must agree to fully fund the commercial crew program.
“To do this we need for Congress to approve full funding for the Commercial Crew Program,” Bolden said at last week’s JSC media briefing.
Severe budget cuts by Congress forced NASA into a two year delay in the first commercial crew flights to the ISS from 2015 to 2017 – and also forced NASA to pay hundreds of millions of more dollars to the Russians for crews seats aboard their Soyuz instead of employing American aerospace workers.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
It only makes sense. Sunlight heats a comet and causes ice to vaporize. This leads to changes in the appearance of surface features. For instance, the Sun’s heat can gnaw away at the ice on sunward-facing cliffs, hollowing them out and eventually causing them to collapse in icy rubble. Solar heating can also warm the ice that’s beneath the surface.
When it becomes a vapor, pressure can build up, cracking the ice above and releasing sprays of gas and dust as jets. New images compared to old suggest the comet’s surface is changing as it approaches the Sun.
Recent photos taken by the Rosetta spacecraft reveal possible changes on the surface of 67P/Churyumov-Gerasimenko that are fascinating to see and contemplate. In a recent entry of the Rosetta blog, the writer makes mention of horseshoe-shaped features in the smooth neck region of the comet called “Hapi”. An earlier image from Jan. 8 may show subtle changes in the region compared to a more recent image from Jan. 22. We’ll get to those in a minute, but there may be examples of more vivid changes.
I did some digging around and found what appears to be variations in terrain between photos of the same Hapi region on Dec. 9 and Jan.8. Just as the other writer took care to mention, viewing angle and lighting are not identical in the images. That has to be taken into account when deciding whether a change in a feature is real or due to change in lighting or perspective.
But take a look at those cracks in the December image that appear to be missing in January’s. The change, if real, is dramatic. If they did disappear, how? Are they buried in dust released by jets that later drifted back down to the surface?
Now back to those horseshoe features. Again, the viewing angles are somewhat different, but I can’t see any notable changes in the scene. Perhaps you can. While comets are expected to change, it’s exciting when it seems to be happening right before your eyes.
Today, Feb. 1, concludes the most somber week in NASA history as we remember the fallen astronauts who gave their lives exploring space so that others could reach to the stars – venturing further than ever before!
In the span of a week and many years apart three crews of American astronauts made the ultimate sacrifice and have perished since 1967. Heroes all ! – They believed that the exploration of space was worth risking their lives for the benefit of all mankind.
On Jan. 28, NASA paid tribute to the crews of Apollo 1 and space shuttles Challenger and Columbia, as well as other NASA colleagues, during the agency’s annual Day of Remembrance. Over the past week, additional remembrance ceremonies were held in many venues across the country.
“NASA’s Day of Remembrance honors members of the NASA family who lost their lives while furthering the cause of exploration and discovery,” said a NASA statement.
NASA Administrator Charles Bolden and other agency senior officials held an observance and wreath-laying at Arlington National Cemetery in Virginia on Jan. 28.
“Today we remember and give thanks for the lives and contributions of those who gave all trying to push the boundaries of human achievement. On the solemn occasion, we pause in our normal routines and remember the STS-107 Columbia crew; the STS-51L Challenger crew; the Apollo 1 crew; Mike Adams, the first in-flight fatality of the space program as he piloted the X-15 No. 3 on a research flight; and those lost in test flights and aeronautics research throughout our history,” said Bolden.
“Let us join together … in paying our respects, and honoring the memories of our dear friends. They will never be forgotten. Godspeed to every one of them.”
12 years ago today on Saturday, Feb. 1, 2003, Space Shuttle Columbia suddenly and unexpectedly disintegrated over the skies of Texas during the fiery reentry into the Earth’s atmosphere at the conclusion of the STS-107 science mission. All aboard were lost: Rick Husband, William McCool, David Brown, Laurel Clark, Kalpana Chawla, Michael Anderson, and Ilan Ramon.
Jan. 28 marked the 29th anniversary of the Challenger disaster on the STS-51L mission when it suddenly broke apart 73 seconds after liftoff in 1986. The entire seven person crew were killed; including Dick Scobee, Michael Smith, Ronald McNair, Judy Resnik, Gregory Jarvis, Ellison Onizuka, and the first “Teacher in Space” Christa McAuliffe.
Jan. 27 marks the 48th anniversary of the first of the three disasters when a horrendous cockpit fire at Launch Complex 34 in 1967 killed the Apollo 1 crew of Gus Grissom, Ed White II and Roger Chaffee during a training exercise in the capsule.
Launch Complex 34 on Cape Canaveral Air Force Station in Florida was never used again for a launch and the ruins stand as a stark memorial to the crew of Apollo 1.
An observance was also held on Jan. 28 at the Space Mirror Memorial at NASA’s Kennedy Space Center Visitor Complex.
Today the fallen astronauts legacy of human spaceflight lives on at NASA with the International Space Station (ISS), the development of Commercial Crew manned capsules for low Earth orbit, and the development of the Orion deep space crew exploration vehicle and SLS rocket for NASA’s ambitious plans to send ‘Human to Mars’ in the 2030s.
There are numerous memorials to the fallen crews. Among them are the tribute plaques to all five space shuttle orbiters that were the brainchild of the Space Shuttle Launch Director Mike Leinbach.
The five orbiter plaques were mounted inside the Space Shuttle Firing Room #4, above the Shuttle countdown clock at the Launch Control Center of NASA’s Kennedy Space Center.
The plaques for Columbia and Challenger, the first two shuttles built, include the crew portraits from STS-107 and STS-51L.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
In the past four decades, NASA and other space agencies from around the world have accomplished some amazing feats. Together, they have sent manned missions to the Moon, explored Mars, mapped Venus and Mercury, conducted surveys, and captured breathtaking images of the Outer Solar System. However, looking ahead to the next generation of exploration and the more-distant frontiers that remain to be explored, it is clear that new ideas need to be put forward on how to quickly and efficiently reach those destinations.
Basically, this means finding ways to power rockets that are more fuel and cost-effective while still providing the necessary power to get crews, rovers, and orbiters to their far-flung destinations. In this respect, NASA has been taking a good look at nuclear fission as a possible means of propulsion.
In fact, according to a presentation made by Doctor Michael G. Houts of the NASA Marshall Space Flight Center back in October of 2014, nuclear power and propulsion have the potential to be “game-changing technologies for space exploration.”
As the Marshall Space Flight Center’s manager of nuclear thermal research, Dr. Houts is well-versed in the benefits it has to offer space exploration. According to the presentation he and fellow staffers made, a fission reactor can be used in a rocket design to create Nuclear Thermal Propulsion (NTP). In an NTP rocket, uranium or deuterium reactions are used to heat liquid hydrogen inside a reactor, turning it into ionized hydrogen gas (plasma), which is then channeled through a rocket nozzle to generate thrust.
A second possible method, known as Nuclear Electric Propulsion (NEP), involves the same basic reactor converting its heat and energy into electrical energy which then powers an electrical engine. In both cases, the rocket relies on nuclear fission to generate propulsion rather than chemical propellants, which has been the mainstay of NASA and all other space agencies to date.
Compared to this traditional form of propulsion, both NTP and NEP offer a number of advantages. The first and most obvious is the virtually unlimited energy density it offers compared to rocket fuel. At a steady state, a fission reactor produces an average of 2.5 neutrons per reaction. However, it would only take a single neutron to cause a subsequent fission and produce a chain reaction and provide constant power.
In fact, according to the report, an NTP rocket could generate 200 kWt of power using a single kilogram of uranium for a period of 13 years – which works out to a fuel efficiency rating of about 45 grams per 1000 MW-hr.
In addition, a nuclear-powered engine could also provide superior thrust relative to the amount of propellant used. This is what is known as specific impulse, which is measured either in terms of kilo-newtons per second per kilogram (kN·s/kg) or in the amount of seconds the rocket can continually fire. This would cut the total amount of propellent needed, thus cutting launch weight and the cost of individual missions. And a more powerful nuclear engine would mean reduced trip times, another cost-cutting measure.
Although no nuclear-thermal engines have ever flown, several design concepts have been built and tested over the past few decades, and numerous concepts have been proposed. These have ranged from the traditional solid-core design to more advanced and efficient concepts that rely on either a liquid or a gas core.
In the case of a solid-core design, the only type that has ever been built, a reactor made from materials with a very high melting point houses a collection of solid uranium rods which undergo controlled fission. The hydrogen fuel is contained in a separate tank and then passes through tubes around the reactor, gaining heat and converted into plasma before being channeled through the nozzles to achieve thrust.
Using hydrogen propellant, a solid-core design typically delivers specific impulses on the order of 850 to 1000 seconds, which is about twice that of liquid hydrogen-oxygen designs – i.e. the Space Shuttle’s main engine.
However, a significant drawback arises from the fact that nuclear reactions in a solid-core model can create much higher temperatures than conventional materials can withstand. The cracking of fuel coatings can also result from large temperature variations along the length of the rods, which taken together, sacrifices much of the engine’s potential for performance.
Many of these problems were addressed with the liquid core design, where nuclear fuel is mixed into the liquid hydrogen and the fission reaction takes place in the liquid mixture itself. This design can operate at temperatures above the melting point of the nuclear fuel, thanks to the fact that the container wall is actively cooled by the liquid hydrogen. It is also expected to deliver a specific impulse performance of 1300 to 1500 (1.3 to 1.5 kN·s/kg) seconds.
However, compared to the solid-core design, engines of this type are much more complicated and therefore more expensive and difficult to build. Part of the problem has to do with the time it takes to achieve a fission reaction, which is significantly longer than the time it takes to heat the hydrogen fuel. Therefore, engines of this kind require methods to trap the fuel inside the engine while simultaneously allowing heated plasma the ability to exit through the nozzle.
The final classification is the gas-core engine, a modification of the liquid-core design that uses rapid circulation to create a ring-shaped pocket of gaseous uranium fuel in the middle of the reactor that is surrounded by liquid hydrogen. In this case, the hydrogen fuel does not touch the reactor wall, so temperatures can be kept below the melting point of the materials used.
An engine of this kind could allow for specific impulses of 3000 to 5000 seconds (30 to 50 kN·s/kg). But in an “open-cycle” design of this kind, the losses of nuclear fuel would be difficult to control. An attempt to remedy this was drafted with the “closed cycle design” – aka. the “nuclear lightbulb” engine – where the gaseous nuclear fuel is contained in a series of super-high-temperature quartz containers.
Although this design is less efficient than the open-cycle design and has more in common with the solid-core concept, the limiting factor here is the critical temperature of quartz and not that of the fuel stack. What’s more, the closed-cycle design is expected to still deliver a respectable specific impulse of about 1500–2000 seconds (15–20 kN·s/kg).
However, as Houts indicated, one of the greatest assets nuclear fission has going for it is the long history of service it has enjoyed here on Earth. In addition to commercial reactors providing electricity all over the world, naval vessels (such as aircraft carriers and submarines) have made good use of slow-fission reactors for decades.
Also, NASA has been relying on nuclear reactors to power unmanned craft and rovers for over four decades, mainly in the form of Radioisotope Thermoelectric Generators (RTGs) and Radioisotope Heater Units (RHU). In the case of the former, heat is generated by the slow decay of plutonium-238 (Pu-238), which is then converted into electricity. In the case of the latter, the heat itself is used to keep components and ship systems warm and running.
These types of generators have been used to power and maintain everything from the Apollo rockets to the Curiosity Rover, as well as countless satellites, orbiters and robots in between. Since its inception,a total of 44 missions have been launched by NASA that have used either RTGs or RHUs, while the former-Soviet space program launched a comparatively solid 33.
Nuclear engines were also considered for a time as a replacement for the J-2, a liquid-fuel cryogenic rocket engine used on the S-II and S-IVB stages on the Saturn V and Saturn I rockets. But despite there being numerous versions of solid-core reactors produced and tested in the past, none were ever put into service for an actual space flight.
Between 1959 and 1972, the United States tested twenty different sizes and designs during Project Rover and NASA’s Nuclear Engine for Rocket Vehicle Application (NERVA) program. The most powerful engine ever tested was the Phoebus 2a, which operated for a total of 32 minutes and maintained power levels of more than 4.0 million kilowatts for 12 minutes.
But looking to the future, Houts’ and the Marshall Space Flight Center see great potential and many possible applications for this technology. Examples cited in the report include long-range satellites that could explore the Outer Solar System and Kuiper Belt, fast, efficient transportation for manned missions throughout the Solar System, and even the provisions of power for settlements on the Moon and Mars someday.
One possibility is to equip NASA’s latest flagship – the Space Launch System (SLS) – with chemically-powered lower-stage engines and a nuclear-thermal engine on its upper stage. The nuclear engine would remain “cold” until the rocket had achieved orbit, at which point the upper stage would be deployed and the reactor would be activated to generate thrust.
This concept for a “bimodal” rocket – one which relies on chemical propellants to achieve orbit and a nuclear-thermal engine for propulsion in space – could become the mainstay of NASA and other space agencies in the coming years. According to Houts and others at Marshall, the dramatic increase in efficiency offered by such rockets could also facilitate NASA’s plans to explore Mars by allowing for the reliable delivery of high-mass automated payloads in advance of manned missions.
These same rockets could then be retooled for speed (instead of mass) and used to transport the astronauts themselves to Mars in roughly half the time it would take for a conventional rocket to make the trip. This would not only save time and cut mission costs but also ensure that the astronauts were exposed to less harmful solar radiation during the course of their flight.
To see this vision become reality, Dr. Houts and other researchers from the Marshall Space Center’s Propulsion Research and Development Laboratory are currently conducting NTP-related tests at the Nuclear Thermal Rocket Element Environmental Simulator (or “NTREES”) in Huntsville, Alabama.
Here, they have spent the past few years analyzing the properties of various nuclear fuels in a simulated thermal environment, hoping to learn more about how they might affect engine performance and longevity when it comes to a nuclear-thermal rocket engine.
These tests are slated to run until June 2015 and are expected to lay the groundwork for large-scale ground tests and eventual full-scale testing in flight. The ultimate goal of all of this is to ensure that a manned mission to Mars takes place by the 2030s and to provide NASA flight engineers and mission planners with all the information they need to see it through.
But of course, it is also likely to have its share of applications when it comes to future Lunar missions, sending crews to study Near-Earth Objects (NEOs), and sending craft to the Jovian moons and other locations in the outer Solar System. As the report shows, NTP craft can be easily modified using modular components to perform everything from Lunar cargo landings to crewed missions to surveying Near-Earth Asteroids (NEAs).
The Universe is a big place, and space exploration is still very much in its infancy. But if we intend to keep exploring it and reaping the rewards that such endeavors have to offer, our methods will have to mature. NTP is merely one proposed possibility. But unlike Nuclear Pulse Propulsion, the Daedalus concept, anti-matter engines, or the Alcubierre Warp Drive, a rocket that runs on nuclear fission is feasible, practical, and possible within the near future.
Nuclear thermal research at the Marshall Center is part of NASA’s Advanced Exploration Systems (AES) Division, managed by the Human Exploration and Operations Mission Directorate and including participation by the U.S. Department of Energy.
There’s darkness out there in the cold corners of the solar system.
And we’re not talking about a Lovecraftian darkness, the kind that would summon Cthulhu himself. We’re talking of celestial bodies that are, well. So black, they make a Spinal Tap album cover blinding by comparison.
We recently came across the above true color comparison of Comet 67/P Churyumov-Gerasimenko adjusted for true reflectivity contrasted with other bodies in the solar system. 67/P is definitely in the “none more black” (to quote Nigel Tufnel) category as compared to, well, nearly everything.
Welcome to the wonderful world of albedo. Bob King wrote a great article last year discussing the albedo of Comet 67/P. The true albedo (or lack thereof) of 67/P as revealed by Rosetta’s NAVCAM continues to astound us. Are all comets this black close up? After all, we’re talking about those same brilliant celestial wonders that can sometimes be seen in the daytime, and are the crimson harbingers of regal change in The Game of Thrones, right?
There was also a great discussion of the dark realms of 67/P in a recent SETI Talk:
As with many things in the universe, it’s all a matter of perspective. If you live in the U.S. Northeast and are busy like we were earlier today digging yourself out from Snowmageddon 2015, then you were enjoying a planetary surface with a high albedo much more akin to Enceladus pictured above. Except, of course, you’d be shoveling methane and carbon dioxide-laced snow on the Saturnian moon… Ice, snow and cloud cover can make a world shinny white and highly reflective. Earthshine on the dark limb of the crescent Moon can even vary markedly depending on the amount of cloud and snow cover on the Earth that’s currently rotated moonward.
To confound this, apparent magnitude over an extended object is diffused over its surface area, making the coma of a comet or a nebula appear fainter than it actually is. Engineers preparing for planetary encounters must account for changes in light conditions, or their cameras may just record… nothing.
For example, out by Pluto, Charon, and friends, the Sun is only 1/1600th as bright as seen here on sunny Earth. NASA’s New Horizons spacecraft will have to adjust for the low light levels accordingly during its historic flyby this July. On the plus side, Pluto seems to have a respectable albedo of 50% to 65%, and may well turn out to look like Neptune’s large moon, Triton.
And albedo has a role in heat absorption and reflection as well, in a phenomenon known as global dimming. The ivory snows of Enceladus have an albedo of over 95%, while gloomy Comet 67/P has an albedo of about 5%, less than that of flat black paint. A common practice here in Aroostook County Maine is to take fireplace ashes and scatter them across an icy driveway. What you’re doing is simply lowering the surface albedo and increasing the absorption of solar energy to help break up the snow and ice on a sunny day.
Ever manage to see Venus in the daytime? We like to point out the Cytherean world in the daytime sky to folks whenever possible, often using the nearby Moon as a guide. Most folks are amazed at how easy this daytime feat of visual athletics actually is, owing to the fact that the cloud tops of Venus actually have a higher albedo of 90%, versus the Moon’s murky 8 to 12%.
Apollo 12 command module pilot Richard Gordon remarked that astronauts Al Bean and Pete Conrad looked like they’d been “playing in a coal bin” on returning from the surface of the Moon. And in case you’re wondering, Apollo astronauts reported that moondust smelled like ‘burnt gunpowder’ once they’d unsuited.
Magnitude, global dimming and planetary albedo may even play a role in SETI as well, as we begin to image Earthlike exoplanets… will our first detection of ET be the glow of their cities on the nightside of their homeworld? Does light pollution pervade the cosmos?
And a grey cosmos awaits interstellar explorers as well. Forget Captain Kirk chasing Khan through a splashy, multi-hued nebula: most are of the light grey to faded green varieties close up. Through a telescope, most nebulae are devoid of color. It’s only when a long time exposure is completed that colors too faint to see with the naked eye emerge.
All strange thoughts to consider as we scout out the dark corners of the solar system. Will the Philae lander reawaken as perihelion for Comet 67/P approaches on August 13th, 2015? Will astronauts someday have to navigate over the dark surface of a comet?
I can’t help but think as I look at the duck-like structure of 67/P that one day, those two great lobes will probably separate in a grand outburst of activity. Heck, Comet 17P/Holmes is undergoing just such an outburst now — one of the best it has generated since 2007 — though it’s still below +10th magnitude. How I’d love to get a look at Comet 17P/Holmes up close, and see just what’s going on!
In Kubrick’s and Clark’s 2001 Space Odyssey, there was no question of “Boots or Bots”[ref]. The monolith had been left for humanity as a mileage and direction marker on Route 66 to the stars. So we went to Jupiter and Dave Bowman overcame a sentient machine, shut it down cold and went forth to discover the greatest story yet to be told.
Now Elon Musk, born three years after the great science fiction movie and one year before the last Apollo mission to the Moon has set his goals, is achieving milestones to lift humans beyond low-Earth orbit, beyond the bonds of Earth’s gravity and take us to the first stop in the final frontier – Mars – the destination of the SpaceX odyssey.
Ask him what’s next and nowhere on his bucket list does he have Disneyland or Disney World. You will find Falcon 9R, Falcon Heavy, Dragon Crew, Raptor Engine and Mars Colonization Transporter (MCT).
At the top of his working list is the continued clean launch record of the Falcon 9 and beside that must-have is the milestone of a soft landing of a Falcon 9 core. To reach this milestone, Elon Musk has an impressive array of successes and also failures – necessary, to-be-expected and effectively of equal value. His plans for tomorrow are keeping us on the edge of our seats.
CRS-5, the Cargo Resupply mission number 5, was an unadulterated success and to make it even better, Elon’s crew took another step towards the first soft landing of a Falcon core, even though it wasn’t entirely successful. Elon explained that they ran out of hydaulic fluid. Additionally, there is a slew of telemetry that his engineers are analyzing to optimize the control software. Could it have been just a shortage of fluid? Yes, it’s possible they could extrapolate the performance that was cut short and recognize the landing Musk and crew dreamed of.
The addition of the new grid fins to improve control both assured the observed level of success and also assured failure. Anytime one adds something unproven to a test vehicle, the risk of failure is raised. This was a fantastic failure that provided a treasure trove of new telemetry and the possibilities to optimize software. More hydraulic fluid is a must but improvements to SpaceX software is what will bring a repeatable string of Falcon core soft landings.
“Failure is not an option,” are the famous words spoken by Eugene Kranz as he’s depicted in the movie Apollo 13. Failure to Elon Musk and to all of us is an essential part of living. However, from Newton to Einstein to Hawking, the equations to describe and define how the Universe functions cannot show failure otherwise they are imperfect and must be replaced. Every moment of a human life is an intertwined array of success and failure. Referring only to the final frontier, in the worse cases, teams fall out of balance and ships fall out of the sky. Just one individual can make a difference between his or a team’s success. Failure, trial and error is a part of Elon’s and SpaceX’s success.
He doesn’t quote or refer to Steve Jobs but Elon Musk is his American successor. From Hyperloops, to the next generation of Tesla electric vehicles, Musk is wasting no time unloading ideas and making his dreams reality. Achieving his goals, making milestones depends also on bottom line – price and performance into profits. The Falcon rockets are under-cutting ULA EELVs (Atlas & Delta) by more than half in price per pound of payload and even more with future reuse. With Falcon Heavy he will also stake claim to the most powerful American-made rocket.
Musk’s success will depend on demand for his product. News in the last week of his investments in worldwide space-based internet service also shows his intent to promote products that will utilize his low-cost launch solutions. The next generation of space industry could falter without investors and from the likes of Musk, re-investing to build demand for launch and sustaining young companies through their start-up phases. Build it and they will come but take for granted, not recognize the fragility of the industry, is at your own peril.
So what is next in the SpaceX Odyssey? Elon’s sights remain firmly on the Falcon 9R (Reuse) and the Falcon Heavy. Nothing revolutionary on first appearance, the Falcon Heavy will look like a Delta IV Heavy on steroids. Price and performance will determine its success – there is no comparison. It is unclear what will become of the Delta IV Heavy once the Falcon Heavy is ready for service. There may be configurations of the Delta IV with an upper stage that SpaceX cannot match for a time but either way, the US government is likely to effectively provide welfare for the Delta and even Atlas vehicles until ULA (Lockheed Martin and Boeing’s developed corporation) can develop a competitive solution. The only advantage remaining for ULA is that Falcon Heavy hasn’t launched yet. Falcon Heavy, based on Falcon 9, does carry a likelihood of success based on Falcon 9’s 13 of 13 successful launches over the last 5 years. Delta IV Heavy has had 7 of 8 successful launches over a span of 11 years.
The convergence of space science and technology and science fiction in the form of Musk’s visions for SpaceX is linked to the NASA legacy beginning with NASA in 1958, accelerated by JFK in 1962 and landing upon the Moon in 1969. The legacy spans backward in time to Konstantin Tsiolkovsky, Robert Goddard, Werner Von Braun and countless engineers and forward through the Space Shuttle and Space Station era.
The legacy of Shuttle is that NASA remained Earth-bound for 30-plus years during a time that Elon Musk grew up in South Africa and Canada and finally brought his visions to the United States. With a more daring path by NASA, the story to tell today would have been Moon bases or Mars missions completed in the 1990s and commercial space development that might have outpaced or pale in comparison to today’s. Whether Musk would be present in commercial space under this alternate reality is very uncertain. But Shuttle retirement, under-funding its successor, the Ares I & V and Orion, cancelling the whole Constellation program, then creating Commercial Crew program, led to SpaceX winning a contract and accelerated development of Falcon 9 and the Dragon capsule.
SpaceX is not meant to just make widgets and profit. Mars is the objective and whether by SpaceX or otherwise, it is the first stop in humankind’s journey into the final frontier. Mars is why Musk developed SpaceX. To that end, the first focal point for SpaceX has been the development of the Merlin engine.
Now, SpaceX’s plans for Mars are focusing on a new engine – Raptor and not a Merlin 2 – which will operate on liquified methane and liquid oxygen. The advantage of methane is its cleaner combustion leaving less exhaust deposits within the reusable engines. Furthermore, the Raptor will spearhead development of an engine that will land on Mar and be refueled with Methane produced from Martian natural resources.
The Raptor remains a few years off and the design is changing. A test stand has been developed for testing Raptor engine components at NASA’s Stennis Space Center. In a January Reddit chat session[ref] with enthusiasts, Elon replied that rather than being a Saturn F-1 class engine, that is, thrust of about 1.5 million lbf (foot-lbs force), his engineers are dialing down the size to optimize performance and reliability. Musk stated that plans call for Raptor engines to produce 500,000 lbf (2.2 million newtons) of thrust. While smaller, this represents a future engine that is 3 times as powerful as the present Merlin engine (700k newtons/157 klbf). It is 1/3rd the power of an F-1. Musk and company will continue to cluster engines to make big rockets.
To achieve their ultimate goal – Mars colonization, SpaceX will require a big rocket. Elon Musk has repeatedly stated that a delivery of 100 colonists per trip is the present vision. The vision calls for the Mars Colonization Transporter (MCT). This spaceship has no publicly shared SpaceX concept illustrations as yet but more information is planned soon. A few enthusiasts on the web have shared their visions of MCT. What we can imagine is that MCT will become a interplanetary ferry.
The large vehicle is likely to be constructed in low-Earth orbit and remain in space, ferrying colonists between Earth orbit and Mars orbit. Raptor methane/LOX engines will drive it to Mars and back. Possibly, aerobraking will be employed at both ends to reduce costs. Raptor engines will be used to lift a score of passengers at a time and fill the living quarters of the waiting MCT vehicle. Once orbiting Mars, how does one deliver 100 colonists to the surface? With atmospheric pressure at its surface equivalent to Earth’s at 100,000 feet, Mars does not provide an Earth-like aerodynamics to land a large vehicle.
In 1952, Werner Von Braun in his book “Mars Projekt” envisioned an armada of ships, each depending on launch vehicles much larger than the Saturn V he designed a decade later. Like the invading Martians of War of the Worlds, the armada would rather converge on Mars and deploy dozens of winged landing vehicles that would use selected flat Martian plain to skid with passengers to a safe landing. For now, Elon and SpaceX illustrate the landing of Dragon capsules on Mars but it will clearly require a much larger lander. Perhaps, it will use future Raptors to land softly or possibly employ winged landers such as Von Braun’s after robotic Earth-movers on Mars have constructed ten or twenty mile long runways.
We wait and see what is next for Elon Musk’s SpaceX vision, his SpaceX Odyssey. For Elon Musk and his crew, there are no “wives” – Penelope and families awaiting their arrival on Mars. Their mission is more than a five year journey such as Star Trek. The trip to Mars will take the common 7 months of a Hohmann transfer orbit but the mission is really measured in decades. In the short-term, Falcon 9 is poised to launch again in early February and will again attempt a soft landing on a barge at sea. And later, hopefully, in 2015, the Falcon Heavy will make its maiden flight from Cape Canaveral’s rebuilt launch pad 39A where the Saturn V lifted Apollo 11 to the Moon and the first, last and many Space Shuttles were launched.
Happy Birthday to my sister Sylvia who brought home posters, literature and interest from North American-Rockwell in Downey during the Apollo era and sparked my interest.