http://theconversation.com/after-a-nail-biting-landing-heres-whats-next-for-mars-insight-107749
Month: November 2018
To find Life On Mars, More Orbiters,Advanced Rovers, and Humans Will Be Required
To find life on Mars, we’ll need new orbiters, more advanced rovers, and humans
There’s a good reason NASA hasn’t said they’ve found life on Mars—it’s beyond their current capabilities.
NASA Will Attempt Its Eight Mars Landing In One Week
NASA Will Attempt Its Eighth Mars Landing in One Week
Touching down on the surface of the Red Planet is one of the most difficult engineering challenges ever attempted, and InSight is about to give it a go
InSight is barreling in for a landing on Mars. The spacecraft will make its approach and landing next week via a tried and true method, but even though NASA has pulled this stunt before, dozens of things need to go exactly right during entry, descent, and landing (EDL) for InSight to arrive safely on the surface of the Red Planet.
At 2:47 p.m. EST on November 26, the InSight lander will hit the top of the Martian atmosphere, about 125 kilometers (70 miles) above the surface, traveling at 5.5 kilometers per second (12,000 mph). The craft’s ablative silica heat shield will rise to a temperature of more than 1,500 degrees Celsius—hot enough to melt steel. About three and a half minutes after atmospheric entry, the spacecraft will still be hurtling toward the ground at supersonic speeds. A parachute will deploy to decelerate as much as possible, the heat shield will jettison, and the spacecraft will start looking for the ground with a radar. About six minutes after hitting the atmosphere, the lander will separate from its back shell—still traveling about 180 mph—and fire its retro rockets to bring it the rest of the way home, touching down roughly a minute later.
If everything goes right—while engineers monitor control screens during the “seven minutes of terror,” unable to steer the distant craft in real time—InSight will come to rest in Elysium Planitia on the Monday after Thanksgiving and prepare to begin studying the seismology and internal heat of Mars. NASA can take comfort in the fact that such landings have succeeded in the past, but when you are attempting to land a craft millions of miles away, it’s impossible to prepare for every eventuality.
Whenever a Mars landing approaches, space fans get an earful of statistics. Before Curiosity’s landing, “more than half of all Mars missions have failed.” Before Europe’s ExoMars’ launch, “more missions have failed than not: 28 flops compared to 19 successes.” After the ExoMars orbiter succeeded, but its lander did not (at least, not entirely): “Of the about a dozen robotic lander and rover missions launched to Mars, only seven have succeeded.”
The statistics are dramatic, but the story they tell is a little dated. There was a spectacular run of failures in the latter part of the 20th century—Mars 96, Mars Observer, Mars Climate Orbiter and Mars Polar Lander’s losses still sting. But while Russia has never achieved a complete success at Mars, NASA, the European Space Agency (ESA) and the Indian Space Research Organisation (ISRO) have all pretty much nailed orbital insertions at Mars since Y2K. China, India and Japan have their second Mars-bound missions in the works, and the United Arab Emirates is planning their first, not to mention the ambitions of several private entities.
Mars orbit insertions have become relatively routine in the 21st century, but Mars landings are still some of the most difficult deep-space missions ever attempted. ESA’s two successful orbiters both included tiny landers that were never heard from after touchdown, though ExoMars’ Schiaparelli lander returned data nearly all the way to the surface.
Three things make a Mars landing much more difficult than a moon landing—or an Earth landing, for that matter. First, unlike the moon, Mars is too far away for any ground-bound human to be in the loop during a landing attempt. The time it takes for a signal to travel from Mars to Earth and back is never less than nine minutes and is usually much longer, so by the time we can hear and respond to a signal that our spacecraft has hit the top of the atmosphere, the end result, one way or another, has already occurred.
The second problem is Mars’ atmosphere. There is both too much and too little. On Earth, when astronauts and sample capsules return from space, we can protect spacecraft behind heat shields and use the friction of atmospheric entry to slow the hypersonic craft to subsonic speeds. Once the flamey part is over, we can simply pop out a parachute to further reduce the velocity and drift to a gentle (or, at least, survivable) touchdown on land or water.
Mars’ atmosphere is thick enough to generate a fiery entry, requiring a heat shield, but it’s too thin for a parachute alone to slow an entering spacecraft to a safe landing speed. When Curiosity hit the top of Mars’ atmosphere in 2012, it was traveling at 5.8 kilometers per second (13,000 mph). When the heat shield had done all it could do, the spacecraft was still hurtling toward the ground at 400 meters per second (895 mph). Curiosity’s parachute could, and did, slow it down, but only to 80 meters per second (179 mph). Hitting the ground at that speed is not survivable, even for a robot.
On an airless world like the moon, heat shields are not required and parachutes do you no good. But fear not, we’ve had the technology for lunar landings since the 1960s: take some rockets and point them downward, canceling out the craft’s velocity.
The atmosphere makes things a little trickier on Mars, though. With moving air as an additional factor, unpredictable winds can add an equally unpredictable horizontal velocity to a descending spacecraft. For this reason, landing regions on Mars are required to have low regional slopes. High horizontal winds plus high slopes could put a lander much farther from, or closer to, the ground than it expects—and either situation could spell disaster.
So a Mars lander needs three technologies to reach the surface: a heat shield, a supersonically deployable parachute and retrorockets. The Viking missions to Mars in the mid-1970s prepared by test-launching parachutes on suborbital rockets to verify that they could inflate without shredding at faster-than-sound speeds. All successful Mars landings since then (all of them NASA’s) have relied on parachutes with Viking legacy. Recently, NASA has worked on a new effort to develop deceleration technologies able to land spacecraft heavier than the Viking probes—an effort that was not, initially, successful, resulting in catastrophically shredded parachutes. (More recent tests have worked better.)
Keeping all of this in mind, what do we know about what went wrong for recently failed Mars landers? For two of them—Mars Polar Lander and Beagle 2—we can only speculate. The spacecraft had no ability to transmit real-time telemetry data as they descended. The Mars Polar Lander failure taught NASA an important lesson: If we are to learn anything from our failures, we have to collect as much data as we can up to the point of failure. Ever since the Mars Polar Lander crashed into the surface at the end of 1999, every Mars lander except ESA’s Beagle 2 has transmitted data to an orbiter that recorded raw radio signals for future analysis in the event of failure.
These days, there are many orbiters at Mars, so we can do even better than that. There’s always one orbiter listening to and recording every last bit of radio signal from a lander, just in case of disaster. And there’s usually a secondary orbiter that doesn’t just listen to the signal, but decodes it and relays the information to Earth as fast as the slow travel of light will allow. This “bent-pipe” data transmission has given us the adrenaline-laced, real-time picture of Mars landing attempts.
When InSight lands, it will fall to the Mars Reconnaissance Orbiter to record telemetry for future dissection if the attempt fails. To get real-time data of the landing, however, InSight has brought along two little spacefaring companions: the MarCO CubeSats, each only about three feet long. The Mars Cube One spacecraft are the first-ever interplanetary CubeSats. If the craft succeed, the world will get its real-time reports on InSight’s landing, and the little space robots will pave the way for future, tinier, cheaper trips to Mars.
But for now, all eyes are on InSight. NASA has successfully landed on Mars seven times, and before the month is out, the space agency is going to try to make it eight.
Preferred Landing Site For ExoMars 2020 Rover Mission Revealed
Preferred landing site for ExoMars 2020 rover mission revealed
When the ExoMars 2020 mission touches down on the Red Planet, it will most likely be at Oxia Planum. The ExoMars Landing Site Selection Working Group has announced that this flat area near the Martian equator was recommended for the ESA-Roscosmos rover and surface science platform because it provides the best chances for finding signs of life, balanced against the need for a safe landing zone.
Oxia Planum is the lead contender of two primary landing sites under consideration by the Working Group. The other area is Mawrth Vallis, and both are located only a few hundred kilometers apart in the same region located north of the equator and have an elevation of about 3,000 m (1.8 mi) below the Martian equivalent of “sea level.”
According to ESA, the site dates back to the time when liquid water could exist on the surface of the Mars – about four billion years ago. It boasts one of the richest known clay deposits on the planet and there are numerous channels running from the southern highlands to the northern lowlands, exposing older and interesting geological deposits.
This is particularly important because the primary goals of the unmanned ExoMars mission is to make the first search for direct signs of life on Mars since the NASA Viking lander missions of the 1970s. This means that during its recent two-day meeting at the National Space Centre in Leicester, England, the Working Group had to find the sweet spot between scientific, engineering, and technical requirements, and is the latest in five years of detailed examination of up to eight candidates.
The Group had to find a site with a low enough elevation to provide enough atmosphere for the parachutes during descent, a choice of landing zones free of obstacles for landing and deployment, and a number of scientifically interesting areas within driving distance without too much in the way of steep slopes or loose debris.
ESA says Oxia Planum meets these requirements with its clay deposits, wet ancient history, and recently exposed deposits that includes ones that have been sealed by later volcanic activity, protecting them from only the most recent erosion and space radiation.
“With ExoMars we are on a quest to find biosignatures,” says ESA’s ExoMars 2020 project scientist Jorge Vago. “While both sites offer valuable scientific opportunities to explore ancient water-rich environments that could have been colonized by microorganisms, Oxia Planum received the majority of votes. An impressive amount of work has gone into characterizing the proposed sites, demonstrating that they meet the scientific requirements for the goals of the ExoMars mission. Mawrth Vallis is a scientifically unique site, but Oxia Planum offers an additional safety margin for entry, descent and landing, and for traversing the terrain to reach the scientifically interesting sites that have been identified from orbit.”
ExoMars 2020 is slated to launch between July 25 and 13 August 2020 atop a Proton-M rocket from Baikonur, Kazakhstan for a landing on Mars on March 19, 2021. In the meantime, the latest landing site selection will undergo internal review by ESA and Roscosmos and an official confirmation in mid-2019.
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Once Upon An Ocean
Once Upon an Ocean
Mars probably won’t be habitable anytime soon, but scientists still remain hopeful about the planet’s life-carrying potential.
Recently, a study in Nature Geoscience suggested that pockets of salty water with enough dissolved oxygen to support life may rest under Mars’ surface, Smithsonian Magazine reported.
Researchers used computer models to determine the possible existence of these brine puddles and their ability to support microorganisms.
In the best-case scenario, the models suggested the puddles could have enough oxygen to support complex organisms like sponges. Even in the worst-case scenario, bacteria could thrive.
“There are so many abiotic ways of creating small but sufficient amounts of oxygen which then, at the colder temperatures, can be absorbed effectively and could actually maybe trigger evolution in a different way than we got on the Earth,” lead author Vlada Stamenković told Space.com
Judging by landscape features and manganese oxide that must have formed on the surface in wet, oxygen-rich conditions, scientists hypothesize that oceans covered Earth’s neighbor billions of years ago.
The team cannot yet prove the existence of the briny puddles, or if they hold any life, but the researchers plan to further test their results.
For now, it’s just a theory.