The lunar module above the Moon during the Apollo 11 mission (NASA)
Back in 2008, Richard Branson outlined his vision for Virgin Galactic’s future. Once tourists are taken into Earth orbit, it seems possible that space hotels could be developed for longer stop-overs in space. He then went on to mention that short “sight-seeing” tours to the Moon could be started from these ultimate hotels. If we are to make travel to the Moon routine enough to send tourists there, the trip would need to be as short as possible.
So how long is the commute from the Earth to the Moon anyway? Human beings and machines have made that trip on several occasions. And while some took a very long time, others were astonishingly fast. Let’s review the various missions and methods, and see which offers the most efficient and least time-consuming means of transit.
The Earth straddling the limb of the Moon, as seen from above Compton crater on the lunar farside, taken by the Lunar Reconnaissance Orbiter spacecraft. Credit: NASA/GSFC/Arizona State University.
Nearly 47 years ago, the crew of Apollo 8 took an image of planet Earth from the Moon that has been called “the most influential environmental photograph ever taken.” Called Earthrise, the picture represented the first time human eyes saw their homeworld come into view around another planetary body.
An artist's image of Hayabusa leaving Earth. Hayabusa was a Japanese sample return mission to the asteroid 25143 Itokawa. The mission was a partial success. A sample mission to Earth's sister planet is the holy-grail for the exploration of Venus. Image credit: JAXA
A space-faring friend pays our fair planet a visit this week on the morning of December 3rd, as the Japanese Space Agency’s Hayabusa 2 spacecraft passes the Earth.
The Flyby
Rick Baldridge on the SeeSat-L message board notes that Hayabusa-2 will pass 9,520 kilometers from the Earth’s center or 3,142 kilometers/1,885 miles from the Earth’s surface at 10:08 UT/5:08 AM EST on Thursday, December 3rd, passing from north-to-south above latitude 18.7 north, longitude 189.8 east just southwest of the Hawaiian Islands.
Unfortunately, the sighting opportunities for Hayabusa-2 aren’t stellar: even at its closest, the 1.5 meter-sized spacecraft is about nine times more distant than the International Space Station and satellites in low Earth orbit. To compound the challenge, Hayabusa-2 passes into the Earth’s shadow from 9:58 UT to 10:19 UT.
The path of Hayabusa-2 past the Earth. Image credit: JAXA
Still, skilled observers with large telescopes and sophisticated tracking rigs based along the Pacific Rim of North America might just catch sight of Hayabusa-2 as it speeds by. The JPL Horizons ephemeris generator is a great resource to create a customized positional chart in right ascension and declination for spacecraft for your given location, including Hayabusa-2.
The Earth-Moon pair snapped by Hayabusa-2 on November 26th from about three million kilometers distant. Image credit: JAXA
Hayabusa-2 won’t crack 20 degrees elevation for observers along the U.S. West Coast, putting it down in the atmospheric murk of additional air mass low to the horizon. This also tends to knock the brightness of objects down a magnitude or so… estimates place Hayabusa-2 at around magnitude +13 shortly before entering the Earth’s shadow. That’s pretty faint, but still, there are some dedicated observers with amazing rigs out there, and it’s quite possible someone could nab it. Hawaii-based observers should have the best shot at it, though again, it’ll be in the Earth’s shadow at its very closest…
Amateur radio satellite trackers are also on the hunt for the carrier-wave signal of the inbound Hayabusa-2 mission. You can also virtually fly along with the spacecraft until December 5th: (H/T @ImAstroNix):
A simulation of tomorrow’s flyby. Image Credit: JAXA
Probably the best eye-candy images will come from the spacecraft itself: already, Hayabusa-2 has already snapped some great images of the Earth-Moon pair using its ONC-T optical navigation camera during its inbound leg.
A close-up of Hayabusa-2’s view of the Earth and Moon. Image credit: JAXA
Other notable missions used Earth flybys en route to their final destinations, including Cassini in 1999, and Juno in 2013. Cassini’s return caused a bit of a stir as it has a plutonium-powered RTG aboard, though Earth and its inhabitants were never in danger. A nuclear RTG actually reentered during the return of Apollo 13, with no release of radioactive material. Meant for the ALSEP science package on the surface of the Moon, it was deposited on the reentry of the Lunar Module over the Marinas Trench in the South Pacific. And no, Hayabusa-2 carries no radioactive material, and in any event, it’s missing the Earth by about a quarter of its girth.
The successor to the Hayabusa (‘Peregrine Falcon’ in Japanese) mission which carried out a historic asteroid sample return from 25143 Itokawa in 2010, Hayabusa-2 launched atop an H-IIA rocket from Tanegashima, Japan exactly a year ago tomorrow on a six year mission to asteroid 162173 Ryugu. This week’s Earth flyby will boost the spacecraft an additional 1.6 kilometers per second to an outbound velocity towards its target of 31.9 kilometers per second post-flyby.
Launch of an H-IIA rocket with Hayabusa-2. Image credit: JAXA
Like its predecessor, Hayabusa-2 is a sample return mission. Unlike the original Hayabusa, however, Hayabusa-2 is more ambitious, also carrying the MASCOT (Mobile Asteroid Surface Scout) lander and an explosive seven kilogram impactor. Hayabusa-2 will deploy a secondary camera in orbit to watch the detonation and will briefly touch down at the impact site to collect material.
If all goes as planned, Hayabusa-2 will return to Earth in late 2020.
NASA has its own future asteroid sample return mission planned, named OSIRIS-REx. This mission will launch in September of next year to rendezvous with asteroid 101955 Bennu in September 2019 and return to Earth in September 2023.
An artist’s conception on Hayabusa 2 at asteroid 162173 Ryugu. Image credit: JAXA
We’re entering the golden age of asteroid exploration, for sure. And this all comes about as the U.S. authorized asteroid mining just last week (or at least, as stated, ‘asteroid utilization’) under the controversial U.S. Commercial Space Launch Competitiveness Act. But the original Hayabusa mission brought back mere micro-meter-sized dust grains, highlighting just how difficult asteroid mining is using present technology…
Perhaps, for now, its more cost effective to simply wait for the asteroids to come to us as meteorites and just scoop ’em up. We’ll be keeping an eye out over the next few days for images of Hayabusa-2 as it speeds by, and more postcards of the Earth-Moon system from the spacecraft as it heads towards its 2018 rendezvous with destiny.
According to a new study, EDLS hardware that has been jettisoned on Mars could create problems for future missions to the same landing sites. Credit: NASA
On future missions, a silver, metallic-based thermal control coating will be bonded to the Orion crew module’s back shell tiles. Credit: NASA
In the wake of NASA’s supremely successful inaugural test flight of the Oriondeep space capsule on the EFT-1 mission in Dec. 2014, NASA is beefing up the critical thermal protection system (TPS) that will protect astronauts from the searing heats experienced during reentry as the human rated vehicle plunges through the Earth’s atmosphere after returning from ambitious expeditions to the Moon and beyond.
Based in part on lessons learned from EFT-1, engineers are refining Orion’s heat shield to enhance the design, ease manufacturing procedures and significantly strengthen is heat resistant capabilities for the far more challenging space environments and missions that lie ahead later this decade and planned further out in the future as part of NASA’s agency-wide ‘Journey to Mars’ initiative to send humans to the Red Planet in the 2030s.
A pretty crescent moon will be the first thing you'll see appear in the sky tonight. Look southwest shortly after sunset to spot it. Source: Stellarium
Clear night ahead? Let’s see what’s up. We’ll start close to home with the Moon, zoom out to lonely Fomalhaut 25 light years away and then return to our own Solar System to track down the 7th planet. Even before the sky is dark, you can’t miss the 4-day-old crescent Moon reclining in the southwestern sky. Watch for it to wax to a half-moon by Thursday as it circles Earth at an average speed of 2,200 mph (3,600 km/hr). That fact that it orbits Earth means that the angle the Moon makes with the sun and our planet constantly varies, the reason for its ever-changing phase.
You’ll see two and possibly three lunar “seas” tonight (Nov. 15). Only a portion of Mare Tranquilliitatis (Seas of Tranquility) is exposed. The large crater Janssen, 118 miles wide and 1.8 miles deep, is visible in binoculars. Credit: Virtual Moon Atlas / Legrande and Chevalley
With the naked eye you’ll be able to make two prominent dark patches within the crescent — Mare Crisium (Sea of Crises) and Mare Fecunditatis (Sea of Fecundity). Each is a vast, lava-flooded plain peppered with thousands of craters , most of which require a telescope to see. Not so Janssen. This large, 118-mile-wide (190-km) ring will be easy to pick out in a pair of seven to 10 power binoculars. Janssen is named for 19th century French astronomer Pierre Janssen, who was the first to see the bright yellow line of helium in the sun’s spectrum while observing August 1868 total solar eclipse.
Piscis Austrinus, the Southern Fish, has but one bright star, 1st magnitude Fomalhaut. It shines all by its lonesome in the south around 7 p.m. local time at mid-month. The star is located only 25 light years from Earth. Source: Stellarium
English scientist Norman Lockyer also observed the line later in 1868 and concluded it represented a new solar element which he named “helium” after “helios”, the Greek word for sun. Helium on Earth wouldn’t be discovered for another 10 years, making this party-balloon gas the only element first discovered off-planet!
See the fish now? Greek mythology tells us that Piscis Austrinus is the “Great Fish”, the parent of the two fish in the zodiacal constellation of Pisces the Fish. Source: Stellarium
Directing your gaze south around 7 o’clock, you’ll see a single bright star low in the southern sky. This is Fomalhaut in the dim constellation of Piscis Austrinus, the Southern Fish. The Arabic name means “mouth of the fish”. If live under a dark, light-pollution-free sky, you’ll be able to make out a loop of faint stars vaguely fish-like in form. Aside from being the only first magnitude star among the seasonal fall constellations, Fomalhaut stands out in another way — the star is ringed by a planet-forming disk of dust and rock much as our own Solar System was more than 4 billion years ago.
The planet Fomalhaut b orbits Fomalhaut inside a circumstellar disk of dust and rock, taking about 1,700 years to orbit. Brilliant Fomalhaut, represented by the small, white dot, has been masked from view, so astronomers could photograph the much fainter disk. Credit: NASA / ESA / Hubble Space Telescope
Within that disk is a new planet, Fomalhaut b, with less than twice Jupiter’s mass and enshrouded either by a cloud of dusty debris or a ring system like Saturn. Fomalhaut b has the distinction of being the first extrasolar planet ever photographed in visible light. The plodding planet takes an estimated 1,700 years to make one loop around Fomalhaut, with its distance from its parent star varying from about 50 times Earth’s distance from the sun at closest to 300 times that distance at farthest.
Shoot a diagonal across the Square of Pegasus to 4th magnitude Delta Piscium. Point your binoculars here and slide east to 4th magnitude Epsilon and 2° south to the planet Uranus shines at magnitude +5.7 and can be glimpsed with the naked eye from a dark sky site. Time shown is around 7 p.m. local time. See detailed map below. Source: Stellarium
Next, we move on to one of the more remote planets in our own solar system, Uranus. The 7th planet from the sun, Uranus reached opposition — its closest to Earth and brightest appearance for the year — only a month ago. It’s well-placed for viewing in Pisces the Fish after nightfall high in the southeastern sky below the prominent sky asterism, the Great Square of Pegasus.
Wide-field binocular view of Uranus’ travels now through next April. I’ve labeled several stars near the planet with their magnitudes, which are similar in brightness to Uranus, so you’ll know to tell them apart from the planet. The others are naked eye stars in Pisces. Source: Chris Mariott’s SkyMap
A telescope will tease out its tiny, greenish disk, but almost any pair of binoculars will easily show the planet as a star-like point of light slowly marching westward against the starry backdrop in the coming weeks. Check in every few weeks to watch it move first west, in retrograde motion, and then turn back east around Christmas. For those with 8-inch and larger telescopes who love a challenge, use this Uranian Moon Finder to track the planet’s two brightest moons, Titania and Oberon, which glimmer weakly around 14th magnitude.
We’ve barely scratched the surface of the vacuum with these offerings; they’re just a few of the many highlights of mid-November nights that also include the annual Leonid meteor shower, which peaks Tuesday and Wednesday mornings (Nov. 17-18). So much to see!
A tri-planetary grouping from the morning of October 31st. Image credit and copyright: Joseph Brimacombe
So, did this past weekend’s shift back to Standard Time for most of North America throw you for a loop? Coming the day after Halloween, 2015 was the earliest we can now shift back off Daylight Saving Time. Sunday won’t fall on November 1st again until 2020. Expect evenings get darker sooner for northern hemisphere residents, while the planetary action remains in the dawn sky.
Though Mercury has exited the morning twilight stage, the planets Jupiter, Venus and Mars continue to put on a fine show, joined by the waning crescent Moon later this week. The action starts today on November 3rd, which finds +1.9 magnitude Mars passing just 0.68 degrees (40’, just over the apparent diameter of a Full Moon) from brilliant -3.9 magnitude Venus. Though the two nearest planets to the Earth appear to meet up in the dawn sky, Mars is actually 2.5 times more distant than Venus, which sits 74.4 million miles (124 million kilometres) from the Earth. Venus exhibits a 57% illuminated gibbous phase 21” across this week, versus Mars’ paltry 4.5” disc.
The lunar planetary lineup on the morning of November 6th… Image credit: Starry Night Education Software
Watch the scene shift, as the Moon joins the dance this weekend. The mornings of Friday, November 6th and Saturday, November 7th are key, as the Moon passes just two degrees from the Jupiter and Mars pair and just over one degree from Venus worldwide. Similar close pairings of the Moon and Venus adorn many national flags, possibly inspired by a close grouping of Venus and the Moon witnessed by skywatchers of yore.
… and the view the next morning on November 7th. Image credit: Starry Night Education software
Saturday November 7th is also a fine time to try your hand at seeing Venus in the daytime, using the nearby crescent Moon as a guide. The Moon will be only four days from New, and the pair will be 46 degrees west of the Sun, an optimal situation as Venus just passed greatest western elongation 46.4 degrees west of the Sun on October 26th.
Mars meets Venus on November 3rd-4th… the center circle = 1 degree FoV. Image credit: Stellarium
Though Venus may seem like a difficult daytime object, it’s actually intrinsically brighter than the Moon per square arc second. Difficulty finding it stems from seeing it against a low contrast blue daytime sky, its small size, and lack of context and depth. The larger but dimmer Moon actually serves as a good anchor to complete this feat of visual athletics.
Venus from the morning of November 3rd. Image credit and copyright: Shahrin Ahmad
Looking for more? Comet C/2013 US10 Catalina will join the planetary lineup next lunation ‘round, hopefully shining at magnitude +5 as it glides past Venus and the Moon on December 7th. Karl Battams at the U.S. Naval Research Labs has confirmed that Comet US10 Catalina—which reaches perihelion this month on November 15th –should also briefly graze the field of view for SOHO’s LASCO C3 camera on November 7th.
There’s also a few notable lunar occultations this week. The Moon also occults the +5 magnitude star Chi Leonis for viewers around the Gulf of Mexico on November 4th, including a dramatic grazing event for Northern Florida. The Moon also occults the +3.5 magnitude star Omicron Leonis on Nov 4th for Alaska as well.
The occultation footprint for Chi Leonis. The solid lines indicate where the event will occur during darkness and twilight hours, while the dashed lines denote where the event transpires during the daytime. Image credit: Occult 4.2 software
See a bright star near the Venus this week? It’s none other than +3.6 magnitude Beta Virginis (Zavijava). The star passes 15’ from Venus on the morning of November 6th. Stick around ‘til 2069, and you can actually witness Venus occult Beta Virginis. Between Beta Virginis and Mars, Venus has the appearance this week of having the large pseudo-moon it never possessed. From Venus, our Moon would appear near magnitude +0.4 with a disk 6.4” this week, and range 12’ from the Earth.
The closeup view on the morning of November 7th along with a 5 degree Telrad FoV. image credit: Stellarium
Now for the wow factor. All of these disparate objects merely lie along our Earthbound line of sight this week. Traveling at the speed of light (186,282 miles or 299,792 kilometers a second), the Moon lies just over a second away. Venus, Mars and Jupiter are next, at 6, 18, and 49 light minutes out, respectively… and Beta Virginis? It lies 36 light years distant.
This pass of the Moon also sets us up for an occultation of Mars and a dramatic daytime occultation of Venus for North America during the next lunation…
More to come!
-Got pictures of the planetary grouping this week with the Moon? Be sure to send ’em in to Universe Today and our Flickr forum.
WT1190F observed on 9 October 2015 with the University of Hawaii 2.2 meter telescope on Mauna Kea, Hawaii. [Credits: B. Bolin, R. Jedicke, M. Micheli]
Get ready for a man-made fireball. A object discovered by the Catalina Sky Survey on Oct 3rd temporarily designated WT1190F is predicted to impact the Earth about 60 miles (100 km) off the southern coast of Sri Lanka around 6:20 Universal Time (12:20 a.m CST) on November 13.
The object orbits Earth with a period of about three weeks. Because it was also observed twice in 2013 by the same survey team, astronomers have the data they need to model its orbit and trajectory, and as far anyone can tell, it’s likely man-made.
The first two stages of the Saturn V rockets used to send the seven Apollo missions to the Moon fell back to Earth, but the third stage (S-IVB), pictured here, propelled the spacecraft into a lunar trajectory. Could this be WT1190F? Credit: NASA
Solar radiation pressure, the physical “push” exerted by photons of sunlight, is proportional to a space object’s area-to-mass ratio. Small, lightweight objects get pushed around more easily than heavier, denser ones. Taking that factor into account in examining WT1190F’s motion over two years, the survey team has indirectly measured WT1190F’s density at about 10% that of water. This is too low to be a typical asteroid made of rock, but a good fit with a hollow shell, possibly the upper stage of a rocket.
Spectacular re-entry of the Jules Verne ATV-1 cargo ship over the Pacific Ocean on September 29, 2008. Still image from a TV camera operated by Jessie Carpenter and Bill Moede of NASA Ames Research Center. A similar spectacle is expected on November 13 south of Sri Lanka.
It’s also quite small, at most only about six feet or a couple of meters in diameter. Most or all of it is likely to burn up upon re-entry, creating a spectacular show for anyone near the scene. During the next week and a half, the European Space Agency’s NEO (Near-Earth Object) Coordination Centeris organizing observing campaigns to collect as much data as possible on the object, according to a posting on their website. The agency has two goals: to better understand satellite re-entries from high orbits and to use the opportunity to test our readiness for a possible future event involving a real asteroid. The latter happened once before when 2008 TC3(a real asteroid) was spotted on October 6, 2008 and predicted to strike Earth the very next day. Incredibly, it did and peppered the Sudan with meteorites that were later recovered.
Assuming WT1190F is artificial, its trans-lunar orbit (orbit that carries it beyond the Moon) hints at several possibilities. Third stages from the Saturn-V rockets that launched the Apollo missions to the Moon are still out there. It could also be a stage from one of the old Russian or more recent Chinese lunar missions. Even rockets used to give interplanetary probes a final push are game.
Near-Earth object J002E3 discovery images taken by Bill Yeung on September 3, 2002. The 16th magnitude object was tentatively identified as the Apollo 12 third stage rocket. Animation created by Bob Denny.
Case in point. What was thought initially to be a new asteroid discovered by amateur astronomer Bill Yeung on September 3, 2002 proved a much better fit with an Apollo 12 S-IVB (third) stage after University of Arizona astronomers found that spectra taken of the object strongly correlated with absorption features seen in a combination of man-made materials including white paint, black paint, and aluminum, all consistent with Saturn V rockets.
On April 14th 1970, the Apollo 13 Saturn IVB upper stage impacted the moon north of Mare Cognitum. The impact crater, which is roughly 30 meters in diameter, is clearly visible in this photo taken by the Lunar Reconnaissance Orbiter. Credit: NASA/Goddard/Arizona State University
Apollo 13’s booster was the first deliberately crashed into the Moon, where it blew out it a crisp, 98-foot-wide (30-meter) crater. Why do such a crazy thing? What better way to test the seismometers left by the Apollo 12 crew? All subsequent boosters ended their lives similarly in the name of seismography. Third stages from earlier missions — Apollos 8, 10 and 11 — entered orbit around the Sun, while Apollo 12, which is orbiting Earth, briefly masqueraded as asteroid J002E3.
The nominal impact point is located about 60 miles south of the island nation Sri Lanka. Given the object’s small size and mass, it will likely be completely incinerated during re-entry. Credit: Bill Gray at Project Pluto
Bill Gray at Project Pluto has a page up about the November 13 impact of WT1190F with more information. Satellite and asteroid watchers are hoping to track the object before and right up until it burns up in the atmosphere. Currently, it’s extremely faint and moving eastward in Orion. You can click HERE for an ephemeris giving its position at the JPL Horizons site. How exciting if we could see whatever’s coming down before its demise on Friday the 13th!
Asteroid 2015 TB145 isn’t the only cosmic visitor paying our planet a trick-or-treat visit over the coming week. With any luck, the Northern Taurid meteor shower may put on a fine once a decade show heading into early November.
About once a decade, the Northern Taurid meteor stream puts on a good showing. Along with its related shower the Southern Taurids, both are active though late October into early November.
The motion of the radiant of the Northern Taurid meteors from mid-October through mid-November. The shower typically peaks around November 12th annually. Image credit: Stellarium
Specifics for 2015
This year sees the Moon reaching Full on Tuesday October 27th, just a few days before Halloween. The Taurid fireballs, however, have a few things going for them that most other showers don’t. First is implied in the name: the Northern Taurids, though typically exhibiting a low zenithal hourly rate of around 5 to 10, are, well, fireballs, and thus the light-polluting Moon won’t pose much of a problem. Secondly, the Taurid meteor stream is approaching the Earth almost directly from behind, meaning that unlike a majority of meteor showers, the Taurids are just as strong in the early evening as the post midnight early morning hours. As a matter of fact, we saw a brilliant Taurid just last night from light-polluted West Palm Beach in Florida, just opposite to the Full Moon and a partially cloudy sky.
A 2014 Taurid. Image credit and copyright: Brian who is called Brian
In stark contrast to the swift-moving Orionids from earlier this month, expect the Taurid fireballs to trace a brilliant and leisurely slow path across the night sky, moving at a stately 28 kilometre per second (we say stately, as the October Orionids smash into our atmosphere at over twice that speed!)
Ever since the 2005 event, the Northern Taurids seemed to have earned the name as “The Halloween Fireballs” in the meme factory that is the internet. It’s certainly fitting that Halloween should have its very own pseudo-apocalyptic shower. The last good return for the Northern Taurids was 2005-2008, and 2015 may see an upswing in activity as well.
Obviously, something interesting has to be occurring on Comet 2P Encke—the source of the two Taurid meteor streams—to shed the pea-sized versus dust-sized material seen in the Southern and Northern Taurids. With the shortest orbital period 3.3 years of all periodic comets known, the Taurid meteor stream—like Encke itself—follows a shallow path nearly parallel to the ecliptic plane.
Discovered in 1822 by astronomer Johann Encke, Comet 2P Encke has been observed through many perihelion passages over the last few centuries, and passes close to Earth once 33 years, as it last did in 2013.
What constitutes a ‘meteor swarm?’ As with many terms in meteoritics, no hard-and-fast definition of a true ‘meteor swarm’ exists. A meteor storm is generally quoted as having a zenithal hourly rate greater than 1000. Expect activity to be broad over the next few weeks, and the Taurid fireballs always have the capacity to produce the kind of brilliant events captured by security cams and dashboard video cameras that go viral across ye ole Internet.
Watching for fireballs is a thrilling pursuit. These may often leave persistent glowing meteor trails in their wake. We caught the 1998 Leonids from the dark sky deserts of Kuwait, and can attest to the persistence of glowing fireball trails from this intense storm, sometimes for minutes. Again, the 2015 Taurids aren’t expected to reach that level of intensity, though the ratio of fireballs to faint meteors will be enhanced.
The path of the stream isn’t fully understood, and that is where volunteer observations can come in handy. The International Meteor Organization is always looking for reports from skilled observers, as is the American Meteor Society (AMS).
The light curve of the suspected Taurid that hit the Moon on Nov 7th. Image Credit: NASA
There’s even been evidence for a recorded meteorite strike related to the northern Taurid fireballs back in 2015 on the dark limb of the Moon as well, a rare event indeed.
After a slow summer, Fall meteor shower activity is definitely heating up. And though 2015 is an off year for the November Leonids, we’re now almost midway between the 1998-99 outbursts, and the possibility of another grand meteor storm in the early 2030s. And another obscure wildcard shower known as the Alpha Monocerotids may put on a surprise showing in November 2015 as well…
More to come on that. Keep watching the skies, and don’t forget to tweet those Northern Taurid fireball sightings and images to #Meteorwatch!
-Got an image of a Northern Taurid fireball? Send ‘em in to Universe Today for our Flickr forum… we may just feature your pic in an after action round up!
Robotic sampling arm and capture mechanism to collect a multi-ton boulder from an asteroid are under development at NASA Goddard and other agency centers for NASA’s unmanned Asteroid Redirect Vehicle and eventual docking in lunar orbit with Orion crew vehicle by the mid 2020s. Credit: Ken Kremer/kenkremer.com
NASA GODDARD SPACE FLIGHT CENTER, MD – Rigorous testing has begun on the advanced robotic arm and boulder extraction mechanisms that are key components of the unmanned probe at the heart of NASA’s Asteroid Redirect Robotic Mission (ARRM) now under development to pluck a multi-ton boulder off a near-Earth asteroid so that astronauts visiting later in an Orion crew capsule can harvest a large quantity of samples for high powered scientific analysis back on Earth. Universe Today inspected the robotic arm hardware utilizing “leveraged robotic technology” during an up close visit and exclusive interview with the engineering development team at NASA Goddard.
“The teams are making great progress on the capture mechanism that has been delivered to the robotics team at Goddard from Langley,” NASA Associate Administrator Robert Lightfoot told Universe Today.
“NASA is developing these common technologies for a suite of missions like satellite servicing and refueling in low Earth orbit as well as autonomously capturing an asteroid about 100 million miles away,” said Ben Reed, NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager, during an exclusive interview and hardware tour with Universe Today at NASA Goddard in Greenbelt, Maryland, regarding concepts and goals for the overall Asteroid Redirect Mission (ARM) initiative.
NASA is leveraging technology originally developed for satellite servicing such as with the Robotic Refueling Mission (RRM) currently on board the International Space Station(ISS) and repurposing them for the asteroid retrieval mission.
“Those are our two near term mission objectives that we are developing these technologies for,” Reed explained.
The unmanned Asteroid Redirect Robotic Mission (ARRM) to grab a boulder is the essential first step towards carrying out the follow on sample retrieval with the manned Orion Asteroid Redirect Mission (ARM) by the mid-2020s.
ARRM will use a pair of highly capable robotic arms to autonomously grapple a multi-ton (> 20 ton) boulder off the surface of a large near-Earth asteroid and transport it to a stable, astronaut accessible orbit around the Moon in cislunar space.
“Things are moving well. The teams have made really tremendous progress on the robotic arm and capture mechanism,” Bill Gerstenmaier, NASA Associate Administrator for Human Exploration and Operations, told Universe Today.
Then an Orion crew capsule can fly to it and the astronauts will collect a large quantity of rock samples and gather additional scientific measurements.
“We are working on a system to rendezvous, capture and service different [target] clients using the same technologies. That is what we are working on in a nut shell,” Reed said.
This engineering design unit of the robotic servicing arm is under development to autonomously extract a boulder off an asteroid for NASA’s asteroid retrieval mission and is being tested at NASA Goddard. It has seven degrees of freedom and mimics a human arm. Credit: Ken Kremer/kenkremer.com
“Right now the plan is to launch ARRM by about December 2020,” Reed told me. But a huge amount of preparatory work across the US is required to turn NASA’s plan into reality.
Key mission enabling technologies are being tested right now with a new full scale engineering model of the ‘Robotic Servicing Arm’ and a full scale mockup of the boulder snatching ARRM Capture Module at NASA Goddard, in a new facility known as “The Cauldron.”
Capture Module comprising two robotic servicing arms and three boulder grappling contact and restraint system legs for NASA’s Asteroid Redirect Robotic Mission (ARRM). Credit: NASAThe ARRM capture module is comprised of two shorter robotic arms (separated by 180 degrees) and three lengthy contact and restraint system capture legs (separated by 120 degrees) attached to a cradle with associated avionics, computers and electronics and the rest of the spacecraft and solar electric power arrays.
“The robotic arm we have here now is an engineering development unit. The 2.2 meter-long arms can be used for assembling large telescopes, repairing a failed satellite, removing orbital debris and capturing an asteroid,” said Reed.
“There are two little arms and three big capture legs.”
“So, we are leveraging one technology development program into multiple NASA objectives.”
“We are working on common technologies that can service a legacy orbiting satellite, not designed to be serviced, and use those same technologies with some tweaking that we can go out with 100 million miles and capture an asteroid and bring it back to the vicinity of the Moon.”
“Currently the [capture module] system can handle a boulder that’s up to about 3 x 4 x 5 meters in diameter.”
Artists concept of NASA’s Asteroid Redirect Robotic Mission capturing an asteroid boulder before redirecting it to a astronaut-accessible orbit around Earth’s moon. Credits: NASA
The Cauldron is a brand new Goddard facility for testing technologies and operations for multiple exploration and science missions, including satellite servicing and ARRM that just opened in June 2015 for the centers Satellite Servicing Capabilities Office.
Overall project lead for ARRM is the Jet Propulsion Laboratory (JPL) with numerous contributions from other NASA centers and industrial partners.
“This is an immersive development lab where we bring systems together and can do lifetime testing to simulate what’s in space. This is our robotic equivalent to the astronauts NBL, or neutral buoyancy lab,” Reed elaborated.
“So with this same robotic arm that can cut wires and thermal blankets and refuel an Earth sensing satellite, we can now have that same arm go out on a different mission and be able to travel out and pick up a multi-ton boulder and bring it back for astronauts to harvest samples from.”
“So that’s quite a technical feat!”
The Robotic Servicing Arm is a multi-jointed powerhouse designed to function like a “human arm” as much as possible. It builds on extensive prior research and development investment efforts conducted for NASA’s current Red Planetrovers and a flight-qualified robotic arm developed for the Defense Advanced Research Projects Agency (DARPA).
“The arm is capable of seven-degrees-of-freedom to mimic the full functionally of a human arm. It has heritage from the arm on Mars right now on Curiosity as well as ground based programs from DARPA,” Reed told me.
“It has three degrees of freedom at our shoulder, two at our elbow and two more at the wrist. So I can hold the hand still and move the elbow.”
The arm will also be equipped with a variety of interchangeable “hands” that are basically tools to carry out different tasks with the asteroid such as grappling, drilling, sample gathering, imaging and spectrometric analysis, etc.
View of the robotic arm above and gripper tool below that initially grabs the asteroid boulder before the capture legs wrap around as planned for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will later dock with an Orion crew vehicle. Credit: Ken Kremer/kenkremer.com
The ARRM spacecraft will carefully study, characterize and photograph the asteroid in great detail for about a month before attempting the boulder capture.
Why does the arm need all this human-like capability?
“When we arrive at an asteroid that’s 100 million miles away, we are not going to know the fine local geometry until we arrive,” Reed explained to Universe Today.
“Therefore we need a flexible enough arm that can accommodate local geometries at the multi-foot scale. And then a gripper tool that can handle those geometry facets at a much smaller scale.”
“Therefore we chose seven-degrees-of-freedom to mimic humans very much by design. We also need seven-degrees-of-freedom to conduct collision avoidance maneuvers. You can’t do that with a six-degree-of-freedom arm. It has to be seven to be a general purpose arm.”
How will the ARRM capture module work to snatch the boulder off the asteroid?
“So the idea is you come to the mother asteroid and touch down and make contact on the surface. Then you hold that position and the two arms reach out and grab the boulder.”
“Once its grabbed the boulder, then the legs straighten and pull the boulder off the surface.”
“Then the arms nestle the asteroid onto a cradle. And the legs then change from a contact system to become a restraint system. So the legs wrap around the boulder to restrain it for the 100 million mile journey back home.
“After that the little arms can let go – because the legs have wrapped around and are holding the asteroid.”
“So now the arm can also let go of the gripper system and pick up a different tool to do other things. For example they can collect a sample with another tool. And maybe assist an astronaut after the crew arrives.”
“During the 100 million mile journey back to lunar orbit they can be also be preparing the surface and cutting into it for later sample collection by the astronauts.”
Be sure to watch this video animation:
Since the actual asteroid encounter will occur very far away, the boulder grappling will have to be done fully autonomously since there will be no possibility for real time communications.
“The return time for communications is like about 30 minutes. So ‘human in the loop’ control is out of the question.
“Once we get into hover position over the landing site we hit the GO button. Then it will be very much like at Mars and the seven minutes of terror. It will take awhile to find out if it worked.”
Therefore the team at Goddard has already spent years of effort and practice sessions just to get ready for working with the early engineering version of the arm to maximize the probability of a successful capture.
“In this facility we put systems together to try and practice and rehearse and simulate as much of the mission as is realistically possible.”
“It took a lot of effort to get to this point, in the neighborhood of four years to get the simulation to behave correctly in real time with contact dynamics and the robotic systems. So the arm has to touch the boulder with force torque sensors and feed that into a computer to measure that and move the actuators to respond accordingly.”
“So the capture of the boulder is autonomous. The rest is teleoperated from the ground, but not the capture itself.”
How realistic are the rehearsals?
“We are practicing here by reaching out with the arm to grasp the client target using autonomous capture [procedures]. In space the client [target] is floating and maybe tumbling. So when we reach out with the arm to practice autonomous capture we make the client tumble and move – with the inertial properties of the target we are practicing on.”
“Now for known objects like satellites we know the mass precisely. And we can program all that inertial property data in very accurately to give us much more realistic simulations.”
“We learned from all our astronaut servicing experiences in orbit is that the more we know for the simulations, the easier and better the results are for the astronauts during an actual mission because you simulated all the properties.”
“But with this robotic mission to an asteroid there is no backup like astronauts. So we want to practice here at Goddard and simulate the space environment.”
ARRM will launch by the end of 2020 on either an SLS, Delta IV Heavy or a Falcon Heavy. NASA has not yet chosen the launch vehicle.
Several candidate asteroids have already been discovered and NASA has an extensive ongoing program to find more.
Orion crew capsule docks to NASA’s asteroid redirect vehicle grappling captured asteroid boulder orbiting the Moon. Credit: NASA
Again, this robotic technology was selected for development for ARRM because it has a lot in common with other objectives like fixing communications satellites, refueling satellites and building large telescopes in the future.
NASA is also developing other critical enabling technologies for the entire ARM project like solar electric propulsion that will be the subject of another article.
Therefore NASA is leveraging one technology development program into multiple spaceflight objectives that will greatly assist its plans to send ‘Humans to Mars’ in the 2030s with the Orion crew module launched by the monster Space Launch System (SLS) rocket.
The maiden uncrewed launch of the Orion/SLS stack is slated for November 2018.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
At NASA Goddard robotics lab Ben Reed/NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager and Ken Kremer/Universe Today discuss the robotic servicing arm and asteroid boulder capture mechanism being tested for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will dock with an Orion crew vehicle in lunar orbit by the mid 2020s for sample return collection. Credit: Ken Kremer/kenkremer.com
