火星好奇号漫游者带来的六年的照片提供了这颗红色行星壮丽的景观

六个地球年之前,好奇号在火星上做了她叹为观止的降落,开始她寻找这颗红色行星能够曾经有过微生物生命的证据的任务。一些观察者,有13500个,观看这个无人控制的漫游者令人紧张的下降,这需要这个小型的、形如制桶工人的车辆去表演出只在计算机模拟里测试过的精细的动作。她需要从13000英里/小时的速度放慢下来,在Gale Crater内降落,依旧未受伤害。

好奇号的适应力是她探险的特点,浪费了预期两年的太空飞行任务,在今天继续向我们发送关于我们天空中神秘邻居引人注目的信息。这个漫游者的17个相机——从8个黑白的、躲避障碍物的Hazcams到快乐自拍、高清晰度的MAHLI相机都包括——对导航、调查和记录来讲起到了重要作用。

除了一个机器人是否能够拍摄美丽的、令人满意的照片的问题以外,由一个NASA的科学家的小队指导的好奇号拍摄了既对NASA的工作至关重要,也对临时的天文学家来讲非常有趣的照片。就像一个专业的照片制造者,这个漫游者的防溅照相机在NASA有一个录制后续工作的团队,负责将这颗星球的景色混合在一起(虽然好奇号的Mastcams摄远镜头能将150个照片迅速合成一个全部的景象)。

好奇号目前为止的发现已经取得了重大突破。她通过向我们展现火星上的水几十亿年之前是什么样的。着陆的一个月后,她记录了在这颗行星三个地点,那里暴露的基岩里的沙砾有可能曾经在嘈杂的小溪里输送过——一个基于岩石的圆滑性所得出的结论。她的照片也揭示了曾经是河床的Gale Crater有可能在水逐渐远离的地方进入干旱期。刚刚在上个过去的7月,感谢她的侦查,NASA宣布古老的湖泊曾经含有复杂的有机物分子。这个漫游者也已经证明了空气中甲烷的存在,由于这些分子的寿命只有几百年,因此这意味着那里一定有持续存在的发源地,最有可能深藏在这个星球地表下。

“这个发现是极其令人激动的,因为它显示了火星是一个当今活跃的行星,”Caltech planetary科学家和火星专家Bethany Ehlmann在一篇6月份自然地理的论文的关于好奇号关于分子的发现的内容中说到。“这个地方不是寒冷、死气沉沉的,好奇号有可能正在行星适居的区域边缘上空盘旋着。”

目前为止,好奇号为了做出这些发现只穿过了12英里,从布拉德伯里登陆点到夏普山的山脚走了5英里,这个山脚位于盖尔撞击坑的中央。在2014年9月,她开始侦查夏普山的高度,而今天,她在上升中继续采样夏普山多石头的岩层。NASA的调查者希望好奇号将从这些样本里揭晓这颗行星的气候是如何变化的。尽管一个活跃并且持续六星期的全星球沙尘暴已经完全改变了火星的容貌,这个利用核能的漫游者坚持了下来(她太阳能的姐妹机遇号已经进入睡眠状态),对她现在正处于的地方维拉鲁宾岭中采集样本、记录数据,寻找柔软的岩石来挖掘。

对于想监视这个小型探测器的那群人,NASA持续提供好奇号更新的路线和活动,也有她照片库里的添加物。对于更加专心一致的着迷者,除了机器人的老师们正在尝试将好奇号带进教室里以外,来自NASA的喷气推进实验室刚刚释放一个叫做Open Source Rover的更小的、任何人能够建造的、受好奇号影响的探测器(尽管这将花费大约2500美元)。

直到一个到达火星成功的载人太空飞行任务被允许,NASA的科学家们将继续依靠诸如好奇号的漫游者来发送回数据和照片。好奇号正在帮助对未来的那些旅程做计划,测量一个人类探险家在一个双程的探险中预期会接触到多少辐射(她的发现表明一个860天的旅途将辐射人类的比欧洲空间局已经对它的宇航员贯彻的一生的极限还要多一点)。现在,我们拥有好奇号的图片;过去6年中的一些关键性的照片列在了下面。

在Hottah里的古老的溪床

在Hottah里的远古的溪床

这个地方因加拿大的Hottah湖泊而命名,好奇号拍摄了基岩的这张图片——照片很有可能由于一个陨石的裂口而暴露、倾斜——在2012年9月24日用它的Mastcam摄远镜头(或者火星的第39个太阳日)。NASA的科学家们相信在地球上有类似的事情:粘结在沉淀的砾岩里的圆形沙砾块通过水漂浮到一个沙漠暴涨的洪水中。

耶洛奈夫海湾的构造

这个用好奇号的Mastcam摄远镜头拍摄的全景中的第111个照片显示了一个叫Yellowknife Bay的在Gale Crater里的地质洼地,在重要位置里的sheepbed泥岩。这些岩石显示了远古的湖泊和小溪的淤积物,而这些事物则说明这个地区曾经支撑过微生物生命。

Rocknest沙石那里含有几十亿个像素的景色

这个rocknest沙石的位置的由13亿个像素组成的合成物,位于好奇号采集尘埃和沙子的样本,包括896个用她的相机在2012年10月和11月的几天拍摄的照片。好奇号用她的Mastcam摄远镜头拍摄了850张彩色照片,用她的Mascam更宽的摄远镜头拍摄了21张彩色照片,用她Navcams其中的一个拍摄了25张黑白照片。那些彩色照片不是白色平衡的,显示火星上过去有照明取暖的条件。

夏普山的地垛

在接近夏普山底部的地垛和表层可以在这个合成物里被看见,由拍摄于2013年9月7日的照片创造成。这个颜色是根据地球白天的照明来调整的,虽然为了表现出火星空气中的尘埃,一些浅色被留下了。

夏普山底部的岩层

这个岩层——地面上的几层岩石——在这个好奇号在2014年3月25日(第580个太阳日)从形成物拍摄的全景图中,拍摄了向夏普山底部的下沉。根据NASA, 这说明水在夏普山更为高的部分彻底形成之前曾经朝一个流域流动。这个照片是白色平衡的,为了协助地质学家研究岩层。

Namib沙丘的顺风坡

这个stereogram能够在3D中用红蓝眼镜被看见,显示了位于Bagnold沙丘、13英尺高的Namib沙丘顺风的一边,拍摄于2015年12月17日(第1196个太阳日)。由于火星的风,巴格诺德沙丘已经被注意到每地球年由于火星的风增长1码。 就像在地球上,朝着风的沙丘的表面在顺风的一边挡住了风的时候起伏,形成了一个叫做“slip face”的深陡坡。

Murray Buttes里的好奇号自拍照

在2016年9月17日(第1463个太阳日)和2016年9月20日(第1466个太阳日),好奇号在位于夏普山的低部的Murray Buttes里Quela的位置挖掘时用MAHLI相机在这个自拍集中拍摄了60张左右的照片。在这个场景中,比好奇号后方的石头高23英尺、更深的M12方山能被在远处看见。

泥沙变干可能的证据

在2016年12月20日,好奇号在Squid Cove拍摄了这些合成的招牌,显示了泥岩上的多边形有可能是30亿年前在泥里变干的裂缝。形成物支持盖尔裂口的湖泊有可能经历过干旱期的假说。这个照片用Mastcam拍摄且是白色平衡的,为了和地球白天照明的条件一样。

巴格诺德沙丘的波浪形

这个于2017年3月24日和25日(第1647个太阳日),在Ogunquit沙滩上用好奇号的Mastcam摄远镜头拍摄的一张360度全景图中拿出来的白色平衡的巴格诺德沙丘景象,显示了深色的沙丘波纹有距它几英尺远的顶峰,比地球上的沙丘里被观察到的要远的多。能被看见:在更宽的波纹上覆盖着更小的波纹。来自Murray形成物、曾经是河床的沉淀物的基岩在重要位置上是可见的,右边的沙砾也是如此。

在沙尘暴之前和之后的德卢斯钻井

这个位置标志着工程师花费了比一年还多的时间去努力修一个损坏的发动机并造成一个叫做Feed Extended Drilling的新型挖掘技术后,好奇号的第一个能够挖掘的地点。2寸深的洞是好奇号Mastcam摄远镜头在2018年5月21日和6月17日拍摄的,这时处于火星全球的沙尘暴时期。沙尘暴的照片的鲜红色在某种程度上是由于拍摄这个照片所需要的时间更长的暴露,但是这主要因为绿色和蓝色的光遮挡了充满尘埃的云朵。

 

Six Years of Photos from Mars Rover Curiosity Offer Breathtaking Views of the Red Planet

Jacqui Palumbo

Aug 6, 2018 12:54 pm

Six Earth years ago, Curiosity made her spectacular landing on Mars, starting her mission to find evidence that the red planet could have once hosted microbial life. Some 13,500 viewers tuned in to watch the unmanned rover’s nail-biting descent, which required the Mini Cooper-sized vehicle to perform maneuvers that had only been tested in computer simulations. She needed to slow down from 13,000 miles per hour and touch down, unharmed, inside the Gale Crater.

Curiosity’s resilience has been a hallmark of her expedition, blowing past the expected two-year mission length to continue to send us fascinating information today about our mysterious celestial neighbor. The rover’s 17 cameras—which range from eight black-and-white, obstacle-avoiding Hazcams to her selfie-happy, high-resolution MAHLI camera—are instrumental to navigating, investigating, and documenting her surroundings on Mars.

Questions aside about whether or not a robot can take aesthetically pleasing photographs, Curiosity, directed by a team of NASA scientists, does capture imagery that is both critical to NASA’s work and intriguing for casual stargazers. And, like a professional image-maker, the rover-slash-photographer has a post-production team at NASA that composites her captures to show wider views of the planet (though Curiosity’s Mastcams can automatically stitch 150 images into a panoramic view).

Curiosity’s findings so far have resulted in breakthroughs in showing us what water on Mars would have looked like billions of years ago. A month after landing, she documented three sites on the planet where gravel in exposed bedrock was likely once transported through tumultuous streams—a conclusion that was made based on the roundness of the stones. Her photos have also revealed that the Gale Crater, once a lakebed, likely went through dry periods where the water receded. And just this past June, thanks to her investigation, NASA announced that the ancient lake once contained complex organic molecules. The rover has also confirmed the presence of methane in the air, which, because of the molecule’s lifespan of only a few hundred years, means there must be an ongoing source, most likely deep under the planet’s surface.

“It’s incredibly exciting, because it shows that Mars is an active planet today,” said Caltech planetary scientist and Mars expert Bethany Ehlmann, in a National Geographic article from June, about Curiosity’s molecular findings. “It’s not cold and dead—it’s perhaps hovering right on the edge of habitability.”

So far, Curiosity has only traversed a little over 12 miles to make these discoveries, journeying five miles from the Bradbury Landing point to the base of Mount Sharp, which is located centrally in the Gale Crater. In September 2014, she began inspecting the lower level of Mount Sharp, and today, she continues to sample its rocky layers as she makes a slow ascent. NASA investigators hope that Curiosity will reveal through these samples how the planet’s climate has changed. And despite an active six-week global dust storm that has entirely altered Mars’s appearance, the nuclear-powered rover has persevered (her solar-powered sibling, Opportunity, has been put to sleep), sampling and documenting the Vera Rubin Ridge, where she is currently located, looking for soft rocks to drill.

For those who want to keep tabs on the little rover that could, NASA continues to provide regular updates on Curiosity’s path and activities, as well as new additions to her image gallery. For the more dedicated fandom, as well as robotics teachers looking to bring Curiosity to the classroom, engineers from NASA’s Jet Propulsion Laboratory (JPL) have just released the Open Source Rover, a smaller Curiosity-inspired rover that anyone can build (though it will cost about $2,500 to do so).

Until a successful manned mission to Mars is undertaken, NASA scientists will continue to rely on rovers like Curiosity to send back data and images. Curiosity is helping to plan for those future trips, measuring how much radiation a human explorer could expect to be exposed to during a round-trip expedition (her findings show that an 860-day trip will radiate a human slightly more than the lifetime limit that the European Space Agency has implemented for its astronauts). For now, we have Curiosity’s photographs; some pivotal images from the past six years are listed below.

Ancient Streambed at Hottah

Named after Canada’s Hottah Lake, Curiosity took this photo of bedrock—likely exposed and tilted due to a meteorite impact—using its Mastcam telephoto lens on September 14, 2012 (or Sol 39, Mars’s 39th solar day). NASA scientists believe the round gravel pieces cemented in the sedimentary conglomerate were carried by water flow akin to a desert flash flood on Earth.

Yellowknife Bay Formation

This 111-image panorama, photographed with Curiosity’s Mastcam on December 24, 2012 (Sol 137), shows Yellowknife Bay, a geological depression within Gale Crater, with Sheepbed mudstone in the foreground. The rocks reveal the ancient lake and stream deposits that signify that this area could have once supported microbial life.

Rocknest Billion-Pixel Landscape

This 1.3-billion-pixel composite of the Rocknest site, where Curiosity collected dust and sand samples, comprises 896 images shot with three of her cameras over several days in October and November 2012. Curiosity took 850 color images with her Mastcam telephoto lens, 21 color images with her Mastcam wider-angle lens, and 25 black-and-white images with one of her Navcams. The color images were not white-balanced, showing lighting conditions as they were on Mars.

Mount Sharp Buttes

The buttes and layers near the base of Mount Sharp can be seen in this composite, created with images photographed on September 7, 2013 (Sol 387). The colors were adjusted to the daytime lighting of Earth, though some tint was left to show the effect of Martian dust in the air.

Strata at Mount Sharp Base

The strata—layers of rocks of the ground—in this panorama, photographed by Curiosity from the Kimberly formation on March 25, 2014 (Sol 580), is pictured dipping toward the base of Mount Sharp. According to NASA, this indicates that water once flowed toward a basin before the greater part of Mount Sharp was fully formed. This image was white-balanced to help geologists study the strata.

Downwind Side of Namib Sand Dune

This stereogram, which can be viewed in 3D with red-blue glasses, shows the downwind side of the 13-foot-tall Namib Sand Dune, located in the Bagnold Dunes, photographed on December 17, 2015 (Sol 1,196). The Bagnold Dunes have been observed to move up to one yard per Earth year due to Mars’s wind. Like on Earth, wind-facing dune surfaces ripple while the downwind side, sheltered from the wind, forms a steep slope called a “slip face.”

Curiosity Selfie in Murray Buttes

Curiosity snapped the 60-odd images in this selfie composite with the MAHLI camera on September 17, 2016 (Sol 1,463) and September 20, 2016 (Sol 1,466) while drilling at the Quela site in Murray Buttes, located on lower Mount Sharp. In the scene, the darker M12 mesa, which is 23 feet higher than the rocks behind Curiosity, can be seen in the distance.

Possible Evidence of Mud Drying

On December 20, 2016 (Sol 1,555), Curiosity took these composited photos at Squid Cove that show polygon shapes on mudstone that may have been cracks drying in the mud over 3 billion years ago. The formations support the theory that the Gale Crater lake may have undergone drying periods. Taken with the Mastcam, the image was white-balanced to the lighting conditions of daytime Earth.

Bagnold Dune Ripples

Photographed over March 24 and 25, 2017 (Sol 1,647), at Ogunquit Beach, this white-balanced scene of the Bagnold Dunes, taken from a 360-degree panorama shot with Curiosity’s Mastcam, shows dark sand ripples with crests several feet apart, much wider than what has been observed in sand dunes on Earth. Overlaid on the wider ripples, smaller ripples, with crests around 10 times closer together, can be seen. Bedrock from the Murray formation, which was once lakebed sediment, is visible in the foreground, as well as gravel on the right.

Duluth Drilling Before and During Dust Storm

This site marks the first location where Curiosity was able to drill after engineers spent more than a year trying to fix a damaged motor, resulting in a new drilling technique called Feed Extended Drilling (FED). The 2-inch-deep hole was photographed with Curiosity’s Mastcam on May 21, 2018 (Sol 2,058), and again on June 17, 2018, during the global Martian dust storm. The bright red color of the dust-storm image is due in part to the longer exposure required to take the image, but primarily because of the green- and blue-light-blocking dust cloud.

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