Archive for the ‘Space News’ Category
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November 24th, 2017
Artist’s impression of the interstellar asteroid `Oumuamua
Credit: ESO/M. Kornmesser
The UK-based Initiative for Interstellar Studies (i4is) has taken a look at how best to get up close and personal with interstellar asteroid A/2017 U1.
This interstellar interloper is tagged as being more than 1,310 feet (400 meters) in diameter and is currently travelling at 44 kilometers per second with respect to the Sun. That’s much faster than any human-made object to date.
Hidden secrets
“What can be more exciting than chasing this object with a spacecraft and making observations from a close distance? What secrets are hidden on this visitor from our galaxy? The velocity of the object makes it challenging to reach but this challenge might lead to new, innovative mission concepts,” explains the i4is study group.
Credit: Initiative for Interstellar Studies (i4is)
Their findings have been published by way of Project Lyra: Sending a Spacecraft to 1I/’Oumuamua (former A/2017 U1), the Interstellar Asteroid
Lyra is the star constellation from which the interstellar asteroid came from.
High-speed interception
The opportunity to directly study material from other star systems is the quest. But can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity.
Project Lyra participants took a look at different mission durations and their velocity requirements, as well as intercept trajectories.
Several technology options are outlined in their work, ranging from a close solar Oberth Maneuver using chemical propulsion, and the more advanced options of solar and laser sails.
Viable options
“To maximize science return decelerating the spacecraft at ’Oumuamua is highly desirable, due to the minimal science return from a hyper-velocity encounter,” the study paper notes. “It is concluded that although reaching the object is challenging, there seem to be viable options based on current and near-term technology.”
The discovery of the first interstellar object entering our solar system is an exciting event and could be the chance of a lifetime or several lifetimes.
Credit: Breakthrough Initiatives
Important result
The i4is study group concludes that a mission to the object will stretch the boundary of what is technologically possible today. “A mission using conventional chemical propulsion system would be feasible using a Jupiter flyby to gravity assist into a close encounter with the Sun. Given the right materials, solar sail technology or laser sails could be used,” they report.
An important result of the i4is analysis is that the value of a laser beaming infrastructure from the Breakthrough Initiatives’ Project Starshot “would be the flexibility to react quickly to future unexpected events, such as sending a swarm of probes to the next object like 1I/‘Oumuamua.” Indeed, if such an infrastructure would be in place today, “intercept missions could have reached 1I/‘Oumuamua within a year.”
Credit: Initiative for Interstellar Studies (i4is)
Long-term ambition
The long-term ambition of the Initiative for Interstellar Studies (i4is) is to enable both robotic and human exploration and colonization of the nearby stars. “However, we have to start with a plan, that builds from incremental steps year on year and takes us in the right direction and with growth as a key,” their website explains.
To that end, future work within Project Lyra will focus on analyzing the different mission concepts and technology options in more detail and to down select two to three promising concepts for further development.
Resources
To read the Project Lyra study paper, go to:
https://arxiv.org/ftp/arxiv/papers/1711/1711.03155.pdf
More information on the Initiative for Interstellar Studies (i4is) can be found at:
Lastly, take a look at this animation of `Oumuamua passing through the Solar System, issued by the European Southern Observatory (ESO), published on November 20, 2017. This animation shows the path of the interstellar asteroid 1I/2017 (‘Oumuamua) through the Solar System. Observations with ESO’s Very Large Telescope and others have shown that this unique object is dark, reddish in color and highly elongated.
Go the video at:
https://www.youtube.com/watch?time_continue=25&v=Yzha7ji3lsM
Posted in 
Credit: RR Auction
Apollo 11 Buzz Aldrin’s solid gold Lunar Module replica has sold for nearly $150,000 at a recent Boston-based auction.
Cartier Solid Gold Lunar Module Replica sold for $149,861 according to Boston-based RR Auction.
Produced by the legendary jewelry company Cartier, three of the solid gold models of the Lunar Module Eagle was commissioned by a French newspaper and presented to the Apollo 11 astronauts during their post-flight visit to Paris in October 1969.
The astronauts’ visit to Paris came as part of their ‘Giant Step’ international goodwill tour, which brought them to 24 countries in 45 days. In the celebratory mania that ensued, one hundred million people turned out to see the crew who had performed humanity’s greatest triumph…a journey to the Moon and back.
Space memorabilia highlights
“With the upcoming Apollo 11 50th Anniversary interest in space memorabilia remains incredibly strong — as evidenced by the Apollo 11 crew signed flag included in our sale that more than doubled the previous world record price for a public auction,” said Bobby Livingston, Executive VP at RR Auction, in a press statement.
Highlights from the sale include:
Apollo 11 crew signed American flag presentation realized $120,693.
Credit: RR Auction
Apollo 11 Lunar Module flown page with Neil Armstrong notations “Go to Descent” sold for $78,346.
A letter penned by astronaut Michael Collins that notes: “The ultimate value of our lunar landing program cannot be outlined in detail at this time,” writes the future Apollo 11 pilot, “just as it was impossible to foresee all the uses to which the Wright brothers’ invention would be put. The letter sold for $18,616.
Another item was a Neil Armstrong letter in which he states, “Exploration in space, as in any other area, provides answers to old questions, but, perhaps more importantly, provides new questions. New questions are the basis for progress, and progress is the key to a better world in which to live. It sold for $11,837.
Resources
The Space Exploration Auction from RR Auction began on November 9 and concluded on November 16.
More details can be found online at:
Also, go to:
https://www.rrauction.com/past_auction_summary.cfm?auction=518
Credit: ESA/NASA
It takes a Moon village – and the International Space University is onboard by creating a new Moon Village Association.
This week, more than 150 experts, engineers, educators and students from around the world gathered in Strasbourg, France to participate in the first International Moon Village Workshop.
Emerging focus
The consensus of the participants is the Moon Village concept?
First of all, there is immense potential to focus and communicate broadly an emerging focus on lunar exploration and development and activities throughout cis-lunar space (i.e., outer space in the vicinity of Earth and the Moon), according to an International Space University (ISU) press statement.
Also, here’s a factoid about the Moon Village: It is not a single location nor a traditional space project, but is rather a broadly defined conceptual framework encompassing a diverse suite of planned and potential future human activities in space.
Concept of view from a deep space habitat
Credit: ESA
“Beginning now, and continuing into future decades the Moon Village represents a community comprising a wide range of future missions and emerging markets, including scientific research, commercial ventures, profound cultural developments and more,” notes the ISU press statement.
New networks
The Moon Village Association (MVA) partners with non-space organizations to promote international discussion and formulation of plans to foster the implementation of a Moon Village, and is creating networks — international/national/regional — to engage civil society around the world.
Moreover, the MVA has been set up to work with other space and non-space organizations (commercial, non-profit, government, and others) to organize dedicated Moon Village and related events, with the MVA making the results available.
Inside look at one idea the European Space Agency is exploring in its formulation of a “Moon Village” that incorporates 3D printing.
Credit: ESA/ Foster + Partners
For information on how to become involved in realizing the Moon Village, visit:
NASA’s InSight Mars lander is moving forward in testing, nearing “ship and shoot” status next year. The spacecraft is shown here fresh out of intense thermal vacuum test period.
Credit: Lockheed Martin
Littleton, Colorado – InSight, NASA’s next Mars mission is rapidly approaching “ship and shoot” status next year. This Interior Exploration using Seismic Investigations, Geodesy and Heat Transport — InSight for short space speak — has just completed “thermal vac” here at Lockheed Martin Space Systems Company – builder of the Mars-bound craft.
Thermal vacuum testing (TVAC) simulates the cruel environment of space to appraise how the Mars-bound craft and its instruments operate under “flight-like” conditions.
For more information on this next NASA Mars mission, go to my new Space.com story at:
NASA’s Next Mars Lander Passes Big Test Ahead of May 2018 Launch
November 22, 2017 12:39pm ET
https://www.space.com/38868-nasa-mars-lander-insight-testing.html
Curiosity Navcam Left B image taken on Sol 1879, November 18, 2017.
Credit: NASA/JPL-Caltech
Now in Sol 1883, NASA’s Curiosity Mars rover is ready to carry out duties over the upcoming holiday.
Mars rover scientists have put together “two extra-large helpings of science” to get through the Thanksgiving holiday, reports Ryan Anderson, a planetary geologist at the USGS in Flagstaff, Arizona.
The first plan covers sols 1882 through 1886 and will mostly involve sitting in one place and not moving. While in this mode, Curiosity will be cooking a sample of “Ogunquit Beach” in the Sample Analysis at Mars (SAM) Instrument Suite via the Evolved Gas Analysis (EGA) oven.
Before that happens, the rover will use its Mars Descent Imager (MARDI) to look at the ground under the rover to see if anything has moved while the Mars machinery has been sitting at this location.
Curiosity Front Hazcam Left B image acquired on Sol 1882, November 21, 2017.
Credit: NASA/JPL-Caltech
Looking for frost
Anderson notes that at pre-dawn on sol 1883 the robot’s Chemistry and Camera (ChemCam) is to analyze the rock target “Lebombo” and the soil “Oaktree” to look for evidence of frost.
Then, on sol 1885, remote sensing tasks includes use of Mastcam to collect multispectral observations of the target “Hexriver” and ChemCam will analyze the targets “Klipfonteinheuwel” and “Klippan.”
Curiosity Rear Hazcam Right B image taken on Sol 1882, November 21, 2017.
Credit: NASA/JPL-Caltech
Mt. Sharp observations
Anderson says he has advocated for ChemCam to use the Remote Micro-Imager (RMI) to take a closer look at an interesting geologic contact on Mt. Sharp.
Curiosity’s Mastcam is slated to document all of the ChemCam observations, as well as the ChemCam auto-targeted observation from sol 1878. Mastcam will repeat its clast (a rock fragment or grain resulting from the breakdown of larger rocks) survey observation from a few days ago to check for any changes, and then utilize the Alpha Particle X-Ray Spectrometer (APXS) to analyze Klippan and Klipfonteinheuwel overnight.
Before dawn on Sol 1886, Anderson adds that ChemCam will once again analyze Lebombo and Oaktree to look for frost and Navcam and Mastcam will take advantage of the early start to make atmospheric observations.
Second plan
“The second plan for the long weekend covers Sols 1886 through 1888. Mastcam will take pictures of the two frost campaign targets, as well as another atmospheric observation,” Anderson explains.
Then ChemCam and Mastcam will take another look at the Autonomous Exploration for Gathering Increased Science (AEGIS) target from sol 1878.
“This target was given the name ‘Reivilo’ by two of our French colleagues who were on operations today…both named Olivier, who really like the name for some reason,” Anderson says. After that, the Mars Hand Lens Imager (MAHLI) will take a closer look at Klipfonteinheuwel and Klippan and APXS will do an overnight calibration measurement.”
Dust Removal Tool at work. Curiosity Mastcam Right image acquired on Sol 1881, November 20, 2017.
Credit: NASA/JPL-Caltech/MSSS
On Sol 1887 Curiosity will finally move on from the locale where the Mars machinery has been camped for a while, collecting some post-drive images to help with targeting next week.
Lastly, on tap is an untargeted science block.
Distant mesa
Curiosity’s ChemCam will use AEGIS software to automatically pick another target via artificial intelligence. There will be another attempt to observe Mt. Sharp with the RMI, Anderson points out, “this time to check for changes on a distant mesa that I have been monitoring.”
Curiosity ChemCam Remote Micro-Imager photo taken on Sol 1879, November 18, 2017.
Credit: NASA/JPL-Caltech/LANL
The long weekend will wrap up with Navcam observations to check for clouds and dust devils, and Mastcam observations to measure the dust in the atmosphere.
“We on the Curiosity team are thankful every day that we get to be a part of the exploration of Mars,” Anderson concludes, “and next week we’ll pick up where we left off as we continue our campaign to explore Vera Rubin Ridge!”
Credit: ESA
I’ve had a keen interest in orbital debris for decades – writing for various publications on this topic from SpaceNews newspaper, SPACE.com to Foreign Policy magazine, as well as the Bulletin of Atomic Scientists.
Call it a reporter’s instinct, but I believe there’s a line of research that needs exploring: The overall impact of human-made orbital debris, solid and liquid propellant discharges, and other space age substances that reenter the Earth’s atmosphere.
As for total mass of uncontrolled objects and human-made junk that reenters each year – it’s upwards of 80 metric tons. But that’s the trackable big stuff – never mind a deluge of other types of clutter – be it particles from spent solid rocket boosters to still-radioactive coolant that has been leaked from old nuclear-powered Soviet satellites.
It’s a garbage dump of heavenly proportions.
Credit: The Aerospace Corporation/CORDS
Guilt factor
I have been guilty, as have other reporters, of using the toss away line that this incoming material “burns up” – but in my view this is far from accurate. The chemistry from high heating of spacecraft materials – including beryllium, lithium, aluminum, nickel, etc. – is worthy of review, specifically the impact of this inflow of materials into Earth’s atmosphere, top to bottom.
In the recent past, Earth has been on the receiving end of large satellites, such as NASA’s decommissioned Upper Atmosphere Research Satellite (UARS), the Roentgen Satellite, ROSAT, a Germany/US/UK collaboration, as well as the failed Mars probe, Russia’s Phobos-Grunt – a vehicle also loaded with toxic fuels.
Fast forward to the present, keep an eye on China’s Tiangong-1 space lab closing in on its uncontrolled reentry early next year.
Credit: The Aerospace Corporation
Slight-of-hand physics
In my opinion, we have conditioned ourselves to use the words “dissipate” and “burn up” as if some celestial slight-of-hand physics is at work that causes incoming junk to simply “vanish” and “disappear.”
I continue to look into this issue – and have some new upcoming surprises to report.
One early story was my published article in SpaceNews newspaper many years in the past – in fact, now over two decades ago.
Back in June of 1995, I wrote about a series of U.S. Air Force-sponsored studies having found that space hardware re-entering the atmosphere contributes to ozone depletion. The reentry process produces materials that combine with other elements in the Earth’s upper stratosphere that can produce a chemical reaction that leads to ozone reduction.
The studies also found that conventional rocket propellants released during launches produce byproducts that also are harmful to stratospheric ozone.
Lack of analysis
A series of separate space debris and ozone impact reports completed in 1994 were prepared for the Environmental Management Division of the U.S. Air Force’s Space and Missile Systems Center in Los Angeles by TRW’s Space & Electronics Group in Redondo Beach, Calif., and The Aerospace Corporation in El Segundo, Calif.
“The impetus for these studies is to get our arms around what environmental impacts are there, potentially, in using space. This is a new frontier and a lot of this analysis hasn’t been done before,” said John Edwards, project officer of the studies and chief of the Air Force’s Environmental Management Division I noted in my SpaceNews piece.
View of the planet Earth from space during a sunrise.
Credit: SWRI
According to the TRW study entitled “Effects of the Impact of Deorbiting Space Debris on Stratospheric Ozone,” objects re-entering the atmosphere can affect ozone in several ways, but not on a significant level globally.
That said, as an object plows through the Earth’s stratosphere, a shock wave is created that produces nitric oxide, a known cause of ozone depletion. Spacecraft and rocket motors are composed of metal alloys and composite materials that melt away during re-entry. TRW researchers found that these materials, as they undergo intense heating, also form chemicals that react directly or indirectly to consume ozone.
Quadrennial assessment
Again, that was back then…but what about today?
For one, get ready for a new look at the issue of rocket emissions in an approaching United Nations 2018 Quadrennial Global Ozone Assessment that delves into substances that are responsible for ozone depletion.
Overall, given the multi-country upswing in rocket launches, the growth of spacecraft in Earth orbit, and the associated leftovers to get them there – could the Earth’s fragile atmosphere be under attack?
Clutter in the cosmos.
Credit: Used with permission: Melrae Pictures/Space Junk 3D
Just a passing thought – perhaps one not to pass by lightly.
I welcome other opinions on the role that the reentry process of human-made materials might have on the atmosphere, particularly at very high altitudes. Again, I feel that this topic area is worthy of investigation.
Curiosity Mastcam Left image acquired on Sol 1880, November 20, 2017.
Credit: NASA/JPL-Caltech/MSSS
Now in Sol 1882, NASA’s Curiosity Mars rover has wheeled to a new spot on the Red Planet.
A three-sol plan has been scripted, “all about picking interesting targets to explore at our Thanksgiving stopover point,” reports Claire Newman, Environmental Science Theme Lead/Keeper of the Plan for Ashima Research.
Newman explains that the plan also includes setting the robot up for winter “frost detection” experiments, and getting Curiosity’s Sample Analysis at Mars (SAM) Instrument Suite ready “to do some power-hungry analysis while we stay put.”
Curosity Front Hazcam Left B image taken on Sol 1881, November 20, 2017.
Credit: NASA/JPL-Caltech
Winter solstice
The Mars rover is just a few sols from southern winter solstice in Gale Crater on Mars, “which means it’s pretty much the coldest time of year and the best time for Curiosity to try to see water frost on the surface.”
If frost formation is observed, “this provides a lot of information for atmospheric scientists like me, who can use it to test models of when and how much frost should form on different types of surfaces, and to better understand how atmospheric water interacts with the surface and subsurface,” Newman points out. “The problem is that, even in winter, the temperatures in Gale only just dip below the frost point and then only right before dawn.”
Curiosity Mars Hand Lens Imager (MAHLI) photo acquired on Sol 1881, November 20, 2017.
Credit: NASA/JPL-Caltech/MSSS
Stay alert
Newman adds that in previous years of looking for frost, “we seem to have been unlucky…the last time we looked for winter frost, the experiment ran on what turned out to be the warmest night of the week. But this just means we have to stay alert to have a good chance of seeing it.”
Cool down
Science teams have chosen two targets to inspect: a small, smooth-topped sand patch, “Oaktree,” which sits in a kind of rock circle. Also targeted, a small rock with an east-facing slope called “Lebombo.”
“The sand should have a lower thermal inertia than rock, which means that it cools down more overnight and may be more likely to form frost,” Newman notes. “But porous sand can also tend to adsorb water instead of the water freezing on its top. So we also chose a rock target with an east-facing slope so it’s in shadow for as much of the afternoon as possible, which means it should be able to cool down a little more than other rocks overnight.”
Curiosity Rear Hazcam Right B image taken on Sol 1881, November 20, 2017.
Credit: NASA/JPL-Caltech
Hard to detect
Because Mars researchers only expect the frost layer at the rover’s location to be a few microns thick, and to vanish rapidly when temperatures start going up at dawn, it’s very hard to detect with cameras.
“So we’ll be using the ChemCam instrument and its Laser-Induced Breakdown Spectrometer (LIBS) to vaporize the top few microns of the surface at night and look for extra hydrogen in the signal, then compare this to daytime measurements of a similar location on the same target,” Newman says.
Curiosity Mastcam Right image taken on Sol 1879, November 18, 2017.
Credit: NASA/JPL-Caltech/MSSS
Just before dawn
On the plan, the robot was set to take daytime hydrogen measurements first, then in the next plan nighttime measurements are to be taken, just before dawn on Sols 1883 and 1886.
Newman says scientists are keeping their fingers crossed for seeing a big increase in the hydrogen signal on at least one of the targets.
“As well as the frost preparations,” Newman continues, “our new location stood out from a distance as having lots of color variety in Mastcam images, and we were able to access both brighter and darker blocks with the arm.”
Contrast of targets
On the Curiosity script is brushing bright target “Hexriver” to remove the top dust layer with the Dust Removal Tool (DRT) before ChemCam and the Alpha Particle X-Ray Spectrometer (APXS) are done, but the dark target “Zululand” was too small so no brushing will happen first.
Meanwhile, Curiosity’s Mastcam will be providing imaging of these targets, as well as documenting more of the light-gray/blue rocks that drew scientists to target “Natal” and the contrast between the bright and dark toned units on target “Kansa.”
Just before Sol 1880, the rover was to make Radiation Assessment Detector (RAD), Dynamic Albedo of Neutrons (DAN) and Rover Environmental Monitoring Station (REMS) measurements “to get a better idea of the aerosols – dust and water ice – around during the frost experiments,” Newman reports. And finally, the robot’s SAM instrument suite will be preconditioning overnight over Thanksgiving, preparing it to analyze samples from all the way back from the rover’s inspection of the Bagnold Dunes, she concludes.
Credit: Rosie Muñoz on Instagram
NASA’s Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer asteroid sample return mission – mercifully shortened to OSIRIS-Rex, is the first U.S. mission to collect a sample of an asteroid and return it to Earth for study.
Next year, in August 2018, OSIRIS-REx’s approach to asteroid Bennu will begin. It will use an array of small rocket thrusters to match the velocity of Bennu and rendezvous with the space rock.
In March 2021, the window for departure from the asteroid will open, and OSIRIS-REx will begin its return journey to Earth, arriving two and a half years later in September 2023.
The sample return capsule will separate from the spacecraft and enter the Earth’s atmosphere. The capsule containing the asteroid specimens will be collected at the Utah Test and Training Range.
Artist concept of OSIRIS-REx at Bennu. Credit: NASA/Goddard
Pocket spacecraft
Time is on your side – but for the moment take your own pocket spacecraft for an adventure right here on Earth.
Snap a photo of your spacecraft TAG-ing something interesting where you live, work, study or travel. Then share it by using the hashtag #MyOSIRISREx and tagging the mission account on Twitter (@OSIRISREx) or Instagram (@OSIRIS_REx).
Note, when sharing images on social media as part of the #MyOSIRISREx campaign, please be aware that they may be re-shared to a larger audience by the mission accounts and/or other users.
Share a photo
Going somewhere? #MyOSIRISREx has been spotted in 23 countries and 29 U.S. states.
Help fill in the map by printing your own pocket spacecraft and sharing a photo of it TAGing something interesting where you are.
Go to:
http://asteroidmission.org//wp-content/uploads/2017/05/MyOSIRISRExPocketSpacecraft.pdf
Lena Okajima, ALE leader and chief star shooter.
Credit: ALE
Shooting stars on demand…that’s the business plan of ALE Corporation, Inc. of Tokyo, Japan.
ALE (Astro Live Experiences) is a space entertainment startup that wants to create shooting stars by using microsatellites. Its mission is to contribute to scientific research through entertainment. It was founded in September 2011 by Lena Okajima, a serial entrepreneur with a Ph.D. in Astronomy from the University of Tokyo.
ALE’s plan is that in early 2019, the first-ever eye-catching artificial meteors will create a light show in the sky above Hiroshima and the surrounding Setouchi region.
Sky canvas
Natural shooting stars occur when dust particles of several millimeters in size enter the Earth’s atmosphere and burn due to plasma emission.
Microsatellite used to pepper Earth’s atmosphere with artificial meteors.
Credit: ALE
ALE’s artificial shooting star business can turn the nighttime heavens into a “Sky Canvas.”
“We aim to artificially reproduce shooting stars by releasing grains of special material from orbiting artificial satellites into outer space and entering into the atmosphere. The appearance of grain burning in the atmosphere is like a shooting star from the ground, and its radiance can be enjoyed at the same time,” notes the ALE website.
ALE reproduces this artificially by inventing shooting star particles and using specially designed microsatellites.
Credit: ALE
Mass driver
Each of ALE’s mini-spacecraft would be loaded with the shooting star particles. An artificial meteor is ejected by a mass driver installed on a microsatellite. The mass driver injects a “pill” at high velocity that then deorbits into the atmosphere.
Once ejected via the tiny satellite, those particles will travel roughly one-third of the way around the Earth. They then burn upon entering the atmosphere, becoming shooting stars visible from an area some 125 miles (200 kilometers) in diameter on the ground.
For more information, go to:
Check out this video on the enterprising ALE at:
Credit: ESO/M. Kornmesser
This artist’s impression shows the first detected interstellar asteroid:`Oumuamua.
The unique object was discovered on October 19, 2017 by the Pan-STARRS 1 telescope in Hawai`i. Subsequent observations were done by telescopes around the world, including the Canada-France-Hawaii Telescope (CFHT), the United Kingdom Infrared Telescope (UKIRT) and the Keck Telescope on Maunakea, the Gemini South telescope, and the European Southern Observatory (ESO) Very Large Telescope (VLT) in Chile.
Findings show that the object was on a path which must have been travelling through interstellar space for millions of years before its chance encounter with our star system. `Oumuamua seems to be a dark red highly-elongated metallic or rocky object — about 1,300 feet (400 meters) long — and is unlike anything normally found in the Solar System.
`Oumuamua is rapidly fading as it heads out of the solar system and recedes from both the Sun and the Earth, leaving in its wake memories of the science fiction novel, Rendezvous with Rama, by British writer Arthur C. Clarke first published in 1973. Set in the 2130s, the story involves a 31 mile (50-kilometer) cylindrical alien starship that enters Earth’s solar system.
